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HomeMy WebLinkAboutSEPA EPIC-354-86 - THB COLORADO CORPORATION - SILVER VIEW RIDGE SUBDIVISIONSILVER VIEW THB COLORADO CORPORATION 54T" AVE. S0. (I -5 & SLADE WAY) EPIC 354 -86 -, Earth Consultants Inc. Grulrrhnic' it tin} iI • t .. Grulugitilti l4 Eli itunnu ntr.l tic irnibts June 26, 1989 E- 3473 -3A Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 Subject: Site Drainage Geotechnical Recommendations Lot #3, Silver View Tukwila, Washington Dear Ms. Bradshaw: At the request of Ms. Chris Bryant, of Bryant Construction, Inc. Earth Consultants, Inc. (ECI) visited the subject site. The purpose of our visit was to observe the seepage at various locations along the slope immediately west of the existing house, and to make recommendations to control the seepage. SITE CONDITIONS The seepage appears to be the result of natural springs in the hillside. Also, the existing stormwater detention box located just southwest of the southwest corner of the existing residence appears to be leaking adding additional water to the slope. RECOMMENDATIONS Our recommendations to control the seepage along the slope and avoid accumu_ (ating hydrostatic pressures along the foundation walls are as follows: 1. The existing stormwater detention box just off the southwest corner of the house should be checked for leaks and repaired. 2. A berm or drainage swale should be constructed at the top of the slope to divert surface runoff away from slope behind the house. The slope and berm or swale should be seeded with a vegetative cover. 3. The upper two feet of soil along the west wall of the house should be compacted to approximately 90% of the maximum dry density (ASTM) D- 1557 -70), yielding a relatively impermeable surface. This area should then be sloped away from the house at minimum of 3 percent for a distance of approximately ten feet. 1805. 136th Place N.E., Suite 101, Bellevue, Washington 98005 222 E. 26th Street, Suite 101, Tacoma, Washington 98411-9998 Bellevue (206) 643.3780 Seattle (206) 464 -1584 FAX (206) 746-0860 Tacoma (206) 272 -6608 City of Tukwila Planning Department June 26, 1989 E- 3473 -3A Page 2 4. A drainage ditch, constructed of half- rounds of corrugated metal pipe (CMP) or like, should he constructed along the length of the toe of the existing slope. This drainage ditch should be tightlined and provided with positive drainage to a suitable permanent discharge facility, such as a nearby storm drain. If you have any questions or desire additional information, please call us. Very truly yours, EARTH CONSULTANTS, INC. Glen Mann, P.E. Vice President JPS /GM /kml Earth Consultants, Inc. Robert S. Levinson Glen Mann Ralph Isaacs Don Spencer Bill Rodgers Charles Vita William Chang President Vice - President Chief Engineer Environmental Director Environmental Manager Engineering Manager Engineering Manager Earth Consultants Inc. Geotcchnir .ri Iinginr•rrs. Grrdugisiti A I n innunr•nial -, it niisis January 12, 1989 Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 Subject: Plan Review Geotechnical Recommendations Lot 20, Silver View Tukwila, Washington Dear Ms. Bradshaw: E- 3473 -20A We have been retained by JBJ Associates to provide an opinion letter to your office as required in the SEPA conditions relative to construction for the above - referenced project. We have conducted a general site visit of the property, and have also reviewed the amended report and supplemental report prepared by GeoEngineers, Inc., .dated, respectively, March 30, 1987 and June 1, 1987. These reports summarize geotechnical considerations for development in Silver View and include recommendations for foundation preparation, site drainage, and other issues that are typically addressed as part of a geotechnical analysis. We have also reviewed the plot plan and house plan prepared by Crane Design, November 29, 1988, and submitted by the owner of Lot 20 in Silver View, understand will be submitted to the City for a Building Permit. Based upon this conclude that the geotechnical recommendations and limitations outlined in the reports will be applicable to this project, and if followed appropriately, should address the construction requirements for the project. Inc., dated which we review, we referenced adequately We recommend that footing drains be installed around all perimeter footings and tightlined to the storm sewer, that foundations be placed on competent native soils or on compacted structural fill, and that all cuts be made in accordance with the referenced report recommendations. In order to verify that the site conditions are as anticipated in the referenced • geotechnical reports, we recommend that Earth Consultants, Inc..(ECI) be retained to examine the site and footing excavations prior to placement of foundations. 1805 - 136th Place N.E., Suite 101, Bellevue, Washington 98005 222 E. 26th Street, Suite 101, Tacoma, Washington 98411.9998 Bellevue (206) 643.3780 Seattle (206) 464-1584 FAX (206) 746 -0860 Tacoma (206) 272 -6608 Ms. Moria Carr Bradshaw January 12, 1989 E- 3473 -20A Page 2 If the plot plan or house plan should change from the current submitted drawings, ECI should be requested to reevaluate the suitability of the site for the proposed structure, and to respond to this effect in writing. Our review recommendations and conclusions are professional opinions derived in a manner consistent with that level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. Respectfully submitted, EARTH CONSULTANTS, INC. Glen Mann, P. E. Vice- President JPS /GM /kml Earth Consultants, Inc. Earth Consultants Inc. Geotechnical Engineers, Geologists & Environmental Scientists August 30, 1988 E- 3473 -3A Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 Subject: Plan Review Geotechnical Recommendations Lot 3, Silver View Tukwila, Washington Dear Ms. Bradshaw: We have been retained by Bryant Construction to provide an opinion letter to your office as required in the SEPA conditions relative to construction for the above - referenced project. We have conducted a general site visit of the property, and have also reviewed the amended report and supplemental report prepared by GeoEngineers, Inc., dated, respectively, March 30, 1987 and June 1, 1987. These reports summarize geotechnical considerations for development in Silver View and include recommendations for foundation preparation, site drainage, and other issues that are typically addressed as part of a geotechnical analysis. We have also reviewed the plot plan and house plan prepared by Keith Bryant dated-August 22, 1988 and submitted by the owner of Lot 3 in Silver View, which we understand will be submitted to the City for a Building Permit. Based upon this review, we conclude that the geotechnical recommendations and limitations outlined in the referenced reports will be applicable to this project, and if followed appropriately, should adequately address the construction requirements for the project. We recommend that footing drains be installed around all perimeter footings, placed on a two to four inch bed of two -inch washed rock, backfilled with a minimum of twelve (12) inches of two -inch washed rock, and tightlined to the storm sewer. The foundations should be placed on competent native soils or on compacted structural fill, and that all cuts be made in accordance with the referenced report recommendations. 1805 - 136th Place N.E.. Suite 101. Bellevue. Washington 98005 222 E. 26th Street. Suite 103. P.O. Box 111744. Tacoma. Washington 98411 -9998 Bellevue (206) 643-3780 Seattle (206) 464 -1584 Tacoma (2061 272-6608 Ms. Moria Carr Bradshaw August 30, 1988 E- 3473 -3A Page 2 In order to verify that the site conditions are as anticipated in the referenced geotechnical reports, we recommend that Earth Consultants, Inc. (ECI) be retained to examine the site and footing excavations prior to placement of foundations. If the plot plan or house plan should change from the current submitted drawings, ECI should be requested to reevaluate the suitability of the site for the proposed structure, and to respond to this effect in writing. Our review recommendations and conclusions are professional opinions der!.ved in a manner consistent with that level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. Respectfully submitted, EARTH CONSULTANTS, INC. Glen Mann, P. E. Vice - President JPS /GM /kml Earth Consultants, Inc. Earth Consultants Inc. Geotechnical Engineers, Geologists. & Environmental Scientists August 5, 1988 Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 • Subject: Plan Review Geotechnical Recommendations Lot 8, Silver View Tukwila, Washington Dear Ms. Bradshaw: We have been retained by Novastar Enterprises, Inc., to provide an opinion letter to your office as required in the SEPA conditions relative to construction for the above - referenced project. We have conducted a general site visit of the property, . and have also reviewed the amended report and supplemental report prepared by GeoEngineers, Inc., dated, respectively, March 30, 1987 and June 1, 1987. These reports summarize geotechnical considerations for development in Silver View and include recommendations for founda- tion preparation, site drainage, and other issues that are typically addressed as part of a geotechnical analysis. We have also reviewed the plot plan and house plan prepared by Crane Design, Inc., dated January, 1988 and submitted by the owner of Lot 8 in Silver View, which we understand will be submitted to the City for a Building Permit. Based upon this review, we conclude that the geotechnical recommendations and limitations outlined in the referenced reports will be applicable to this project, and if followed appropriately, should adequately address the construction requirements for the project. We recommend that footing drains be installed around all perimeter footings and tightlined to the storm sewer, that foundations be placed on competent native soils or on compacted structural fill, and that all cuts be made in accordance with the referenced report recommendations. In order to verify that the site conditions are as anticipated in the referenced geotechnical reports, we recommend that Earth Consultants, Inc. (ECI) be retained to examine the site and footing excavations prior to placement of foundations. 1805 - 136th Place N.E., Suite 101, Bellevue, Washington 98005 Bellevue (206) 643 -3780 Seattle (206) 464 -1584 222 E. 26th Street, Suite 103, P.O. Box 111744, Tacoma, Washington 98411 -9998 - Tacoma (206) 272 -6608 Ms. Moria Carr Bradshaw August 5, 1988 E- 3473 -8 Page 2 If the plot plan or house plan should change from the current submitted drawings, ECI should be requested to reevaluate the suitability of the site for the proposed structure, and to respond to this effect in writing. Our review recommendations and conclusions are professional opinions derived in a manner consistent with that level of care rand skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. Respectfully submitted, EARTH CONSULTANTS, INC. Glen Mann, P. E. Vice - President DG /GM /kml Earth Consultants, Inc. Earth Consultants Inc. Geotechnical Engineers, Geologists & Environmental Scientists July 12, 1988 Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 Subject: Plan Review Geotechnical Recommendations Lot 6, Silver View Tukwila, Washington Dear Ms. Bradshaw: We have been retained by the owner of Lot 6 to provide an opinion letter to your office as required in the SEPA conditions relative to construction for the above - referenced project. We have conducted .a general site visit of the property, and have also reviewed the amended report and supplemental report prepared by GeoEngineers, Inc., dated, respectively, March 30, 1987 and June 1, 1987. These reports summarize geotechnical considerations for development in Silver View and include recommendations for foundation preparation, site drainage, and other issues that are typically addressed as part of a geotechnical analysis. We have also reviewed the plot plan and house plan prepared by Patrick R. Gleason dated May, 1988, and submitted by the owner of Lot 6 in Silver View, which we understand will be submitted to the City for a Building Permit. Based upon this review, we conclude that the geotechnical recommendations and limitations outlined in the referenced reports will be applicable to this project, and if followed appropriately, should adequately address the construction requirements for the project. We recommend that footing drains be installed around all perimeter footings and tightlined to the storm sewer, that foundations be placed on competent native soils or on compacted structural fill, and that all cuts be made in accordance with the referenced report recommendations: In order to verify that the site conditions are as anticipated in the referenced geotechnical reports, we recommend that Earth Consultants, Inc. (ECI) be retained to examine the site and footing excavations prior to placement of foundations. 1805 - 136th Place N.E., Suite 101, Bellevue, Washington 98005 Bellevue (206) 643 -3780 Seattle (206) 464 -1584 222 E. 26th Street, Suite 103, P.O. Box 111744, Tacoma, Washington 98411 -9998 Tacoma (206) 272 -6608 Ms. Moria Carr Bradshaw July 12, 1988 E- 3473 -6A Page 2 If the plot plan or house plan should change from the current submitted drawings, ECI should be requested to reevaluate the suitability of the site for the proposed structure, and to respond to this effect in writing. Our review recommendations and conclusions are professional opinions derived in a manner consistent with that level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. We trust this information is sufficient to fulfill the SEPA require - ments.'Should you have any questions regarding the content of this letter, please call. Respectfully submitted, EARTH CONSULTANTS, INC. Glen Mann, P. E. Vice - President DG /GM /kml L . L Earth Consultants, Inc. Earth Consultants Inc. Geotechnical Engineers, Geologists U Environmental Scientists June 28, 1988 Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 G JUL 5 1988 Subject: Plan Review Geotechnical Recommendations Lot 16, Silver View Tukwila, Washington Dear Ms. Bradshaw: E- 3473 -16A We have, been retained by JBJ Associates, to provide an .opinion letter to your office as required in the SEPA conditions relative to construction for the above - referenced project. We have conducted a general site visit of the property, and have. -also reviewed the amended report and supplemental- report prepared by GeoEngineers, Inc., 'dated, respectively, March 30, 1987.and'June 1, 1987; These reports summarize geotechnical considerations for development in Silver View and include recommendations for foundation preparation, site drainage, and other issues that are typically addressed as part of a geotechnical analysis. We have also reviewed the plot plan and house plan prepared by James Gallup dated June, 1988 and submitted by the owner of Lot 16 in Silver View, which we understand will be submitted to the City for a Building Permit. Based upon this review; we conclude that the geotechnical recommendations and limitations outlined in the referenced reports will be applicable to this project, and if followed appropriately, should adequately address the construction requirements for the project. We recommend that footing drains be installed around all perimeter footings and tightlined to the storm sewer, that foundations be placed on competent native soils or on compacted structural fill, and that all cuts be made in accordance with the referenced report recommendations. In order to verify. that the -site conditions areas anticipatedin the referenced - geotechnical. reports.,' we recommend :;"that Earth Consultants, Inc. (ECI) be retained to examine the,site' and footing excavations prior .to placement of foundations. 1805 - 136th Place N.E., Suite 101, Bellevue, Washington 98005 Bellevue (206) 643 -3780 Seattle (206) 464 -1584 222 E. 26th Street, Suite 103, P.O. Box 111744, Tacoma, Washington 98411 -9998 Tacoma (206) 272 -6608 Ms. Moria Carr Bradshaw June 28, 1988 E- 3473 -16A Page 2 If the plot plan or house plan should change from the current submitted drawings, ECI should be requested to reevaluate the suitability of the site for the proposed structure, and to respond to this effect in writing. Our review recommendations and conclusions are professional opinions derived in a manner consistent with that level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. Respectfully submitted, EARTH CONSULTANTS, INC. Glen Mann, P. E. Vice - President DG /GM /kml 4anL60 Earth Consultants, Inc. Earth Consultants Inc. Geotechnical Engineers, Geologists U Environmental Scientists June 7, 1988 Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 Subject: Plan Review Geotechnical Recommendations Lot 10, Silver View Tukwila, Washington Dear Ms. Bradshaw: E- 3473 -10 We have been retained by Barghausen.Engineers, Inc., to provide an opinion letter to your office as required in the SEPA.conditions relative to construction for -the above - referenced project. We have conducted a general site visit of the property, and have also reviewed the amended report. and—supplemental.-report prepared by GeoEngineers, Inc.., dated, respectively, March:30,-1987 and June 1, 1987. These reports summarize geotechnical considerations for development in Silver-View and include recommendations for founda- tion preparation, site drainage, and other issues that are typically addressed.as..part of a geotechnical analysis.. . We have also reviewed the plot plan and house plan prepared by Crane Design, Inc., dated July 31, 1987 and submitted by the owner of Lot 10. in Silver -View, which we understand will be submitted to the City for a.Building.Permit. Based upon this review, we conclude that the geotechnical , recommendations and limitations outlined in the referenced reports will be applicable to this project, and if followed appropriately, should adequately address the construction requirements for the project. We recommend that footing drains be installed around all perimeter footings and tightlined to the storm sewer, that foundations be placed on competent - native soils or on compacted structural fill, and that all cuts . be made in accordance with the referenced report recommendations. In order, to verify that the site- :conditions are as anticipated in the referenced geotechnical reports, . we recommend that Earth Consultants, Inc. (ECI) be retained to examine the site and footing excavations prior to placement of foundations. 1805 - 136th Place N.E., Suite 101, Bellevue, Washington 98005 222 E. 26th Street, Suite 103, P.O. Box 111744, Tacoma, Washington 98411 -9998 Bellevue (206) 643 -3780 Seattle (206) 464 -1584 Tacoma (206) 272 -6608 Ms. Moria Carr Bradshaw June 7, 1988 E- 3473 -10 Page 2 If the plot plan or house plan should change from the current submitted drawings, ECI should be requested to reevaluate the suitability of the site for the proposed structure, and to respond to this effect in writing. Our review recommendations and conclusions are professional opinions derived in a manner consistent with that level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. Respectfully submitted, EARTH CONSULTANTS, INC. fsi\tu.,..______-- Glen Mann, P. E. Vice - President DG /GM /kml Earth Consultants, Inc. Earth Consultants Inc. Geotechnical Engineers, Geologists & Environmental Scientists April 15, 1988 E- 3473 -17A Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 Subject: Plan Review Geotechnical Recommendations Lot 17, Silver View Tukwila, Washington Dear Ms. Bradshaw: We have been retained by the owner of Lot 17 to provide an opinion letter to your office as required in the SEPA conditions relative to construction for the above - referenced project. We have conducted a general site visit of the property, and have also reviewed the amended report and supplemental report prepared by GeoEngineers, Inc., dated, respectively, March 30, 1987 and June 1, 1987. These reports summarize geotechnical considerations for development in Silver View and include recommendations for foundation preparation, site drainage, and other issues that are typically addressed as part of a geotechnical analysis. We have also reviewed the plot plan and house plan prepared by Ed O'Brien, dated March 18, 1988, and submitted by the owner of Lot 17 in Silver View, which we understand will be submitted to the City for a Building Permit. Based upon this review, we conclude that the geotechnical recommendations and limitations outlined in the referenced reports will be applicable to this project, and if followed appropriately, should adequately address the construction requirements for the project. We recommend that footing drains be installed around all perimeter footings and.tightlined to the storm sewer, that foundations be placed on competent native soils or on compacted structural fill, and that all cuts be made in accordance with the referenced report recommendations. In order to verify that the site conditions are as anticipated in the referenced geotechnical reports, we recommend that Earth Consultants, Inc. (ECI) be retained to examine the site and footing excavations prior to placement of foundations. 1805. 136th Place N.E., Suite 101, Bellevue, Washington 98005 222 E. 26th Street, Suite 103, P.O. Box 111744, Tacoma, Washington 98411 -9998 Bellevue (206) 643-3780 Seattle (206) 464.1584 Tacoma (206) 272 6608 Ms. Moria Carr Bradshaw April 15, 1988 E- 3473 -17A Page 2 If the plot plan or house plan should change from the current submitted drawings, ECI should be requested to reevaluate the suitability of the site for the proposed structure, and to respond to this effect in writing. Our review recommendations and conclusions are professional opinions derived in a manner consistent with that level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. Respectfully submitted, EARTH CONSULTANTS, INC. Glen Mann, P. E. Vice - President DG /GM /kml Earth Consultants, Inc. Earth Consultants Inc. Geotechnical Engineers, Geologists & Environmental Scientists April 15, 1988 E- 3473 -14 Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 Subject: Plan Review Geotechnical Recommendations Lot 14, Silver View Tukwila, Washington Dear Ms. Bradshaw: We have been retained by Barghausen Engineers, Inc., to provide an opinion letter to your office as required in the SEPA conditions relative to construction for the above - referenced project. We have conducted a general site visit of the property, and have also reviewed the amended report and supplemental report prepared by GeoEngineers, Inc., dated, respectively, March 30, 1987 and June 1, 1987. These reports summarize geotechnical considerations for development in Silver View and include recommendations for founda- tion preparation, site drainage, and other issues that are typically addressed as part of a geotechnical analysis. We have also reviewed the plot plan and house plan prepared by Flynn Associates, Inc., dated April, 1988 and submitted by the owner of Lot 14 in Silver View, which we understand will be submitted to the City for a Building Permit. Based upon this review, we conclude that the geotechnical recommendations and limitations outlined in the referenced reports will be applicable to this project, and if followed appropriately, should adequately address the construction requirements for the project. We recommend that footing drains be installed around all perimeter footings and tightlined to the storm sewer, that foundations be placed on competent native soils or on compacted structural fill, and that all cuts be made in accordance with the referenced report recommendations. In order to verify that the site conditions are as anticipated in the referenced geotechnical reports, we recommend that Earth Consultants, Inc. (ECI) be retained to examine the site and footing excavations prior to placement of foundations. 1805 - 136th Place N.E., Suite 101, Bellevue, Washington 98005 Bellevue (206) 643 -3780 Seattle (206) 464 -1584 222 E. 26th Street, Suite 103, P.O. Box 111744, Tacoma, Washington 98411 -9998 Tacoma (206) 272 -6608 Ms. Moria Carr Bradshaw April 15, 1988 E- 3473 -14 Page 2 If the plot plan or house plan should change from the current submitted drawings, ECI should be requested to reevaluate the suitability of the site for the proposed structure, and to respond to this effect in writing. Our review recommendations and conclusions are professional opinions derived in a manner consistent with that level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. Respectfully submitted, EARTH CONSULTANTS, INC. Glen Mann, P. E. Vice - President DG /GM /kml Cc Wnc��yl �rQ Earth Consultants, Inc. APR U 1988 i Tiff Earth Consultants Inc. Geotechnical Engineers, Geologists ty Environmental Scientists March 30, 1988 E- 3473 -21 Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 Subject: Plan Review Geotechnical Recommendations Lot 21, Silver View Tukwila, Washington Dear Ms. Bradshaw: We have been retained by the owner of Lot 21 to provide an opinion letter to your office as required in the SEPA conditions relative to construction for the above - referenced project. We have conducted a general site visit of the property, and have also reviewed the amended report and supplemental report prepared by GeoEngineers, Inc., dated, respectively, March 30, 1987 and June 1, 1987. These reports summarize geotechnical considerations for development in Silver View and include recommendations for foundation preparation, site drainage, and other issues that are typically addressed as part of a geotechnical analysis. We have also reviewed the plot plan and house. plan No. 120687 prepared by Crane Design, dated January 15, 1988, and submitted by the owner of Lot 21 in Silver View. which we understand will be sub- mitted to the City for a Building Permit. Based upon this review, we conclude that the geotechnical recommendations and limitations outlined in the referenced reports will be applicable to this project, and if followed appropriately, should adequately address the construction requirements for the project. We recommend that footing drains be installed around all perimeter footings and tightlined to the storm sewer, that foundations be placed on competent native soils or on compacted structural fill, and that all cuts be made in accordance with the referenced report recommendations. 1805 - 136th Place N.E., Suite 101, Bellevue, Washington 98005 Bellevue (206) 643 -3780 Seattle (206) 464 -1584 222 E. 26th Street, Suite 103, P.O. Box 111744, Tacoma, Washington 98411-9998 Tacoma (206) 272 -6608 Ms. Moria Carr Bradshaw March 30, 1988 E- 3473 -21 Page 2 We estimate that approximately five feet of structural fill will be required to develop the site as planned. The existing loose fill located on the west side of the site can be used for structural fill provided it can be compacted to 95 percent of its maximum dry density, as determined by ASTM D- 1557 -78 (Modified Proctor). Otherwise, the fill may be used in non -load bearing areas. Structural fill placed under slabs and footings should be placed in thin lifts not exceeding ten inches in loose thickness and should be compacted to at least 95 percent maximum density. Structural fill under slopes, pavements and walks should be placed in similar thin lifts and compacted to at least 95 percent maximum density. In order to verify that the site conditions are as anticipated in the referenced geotechnical reports, we recommend that Earth Consultants, Inc. (ECI) be retained to examine the site and footing excavations prior to placement of foundations. If the plot plan or house plan should change from the current submitted drawings, ECI should be requested to reevaluate the suitability of the site for the proposed structure. Our review recommendations and conclusions are professional opinions derived in a manner consistent with that level of care and skill ordinarily exercised by other members of . the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. Respectfully submitted, EARTH CONSULTANTS, INC. Glen Mann, P. E. Vice - President DG /GM /kml Earth Consultants, Inc. Earth Consultants Inc. Geotechnical Engineers, Geologists & Environmental Scientists February 17, 1988 Ms. Moria Carr Bradshaw Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 Subject: Plan Review Geotechnical Recommendations Lot 19, Silver View Tukwila, Washington Dear Ms. Bradshaw: E- 3473 -19 We have been retained by the THB Colorado Corporation to provide an opinion letter to your office as required in the SEPA conditions for the above - referenced project relative to construction on Lot 19 in Silver View. We have conducted a general site visit of the property, and have also reviewed the amended report and supplemental report prepared by GeoEngineers, Inc. dated, respectively, March 30, 1987 and June. 1, 1987. These reports summarize geotechnical considerations for development in Silver View and include recommen- dations for foundation preparation, site drainage, and other issues that are typically addressed as part of a geotechnical analysis. We have also reviewed the plot plan and house plan No. 100487 prepared by Crane Design dated January 18, 1988, and submitted by the owner of Lot 19 in Silver View, which we understand will be sub- mitted to the City for a Building Permit. Based upon this review, we conclude that the geotechnical recommendations and limitations outlined in the referenced reports will be applicable to this project, and if followed appropriately, should adequately address the construction requirements for the project. We recommend that footing drains be installed around all perimeter footings and tightlined to the storm sewer, that foundations be placed on competent native soils or on compacted structural fill, and that all cuts be made in accordance with the referenced report recommenda- tions. In order to verify that the site conditions are as anticipated in the referenced geotechnical reports, we recommend that Earth Consultants, Inc. (ECI) be retained to examine the site and footing excavations prior to placement of foundations. 1805 - 136th Place N.E., Suite 101, Bellevue, Washington 98005 222 E. 26th Street, Suite 103, P.O. Box 111744, Tacoma, Washington 98411-9998 Bellevue (206) 643 -3780 Seattle (206) 464 -1584 Tacoma (206) 272 -6608 Ms. Moria Carr Bradshaw February 17, 1988 E- 3473 -19 Page 2 If the plot plan or house plan should change from the current submitted drawings, ECI should be requested to reevaluate the suitability of the site for the proposed structure. Our review recommendations and conclusion are professional opinions derived in a manner consistent with that level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. Respectfully submitted, EARTH CONSULTANTS, INC., Glen Mann, P. E. Vice - President DG /GM /kml Earth Consultants, Inc. 0 Geotechnical Engineers, Geologists t! Environmental Scientists Earth Consultants Inc. RECEI'VE'D January 22, 1988 CITY 0� TIJK RA JAN 2 2 1988 Ms. Moria Carr Bradshaw BUILDING DEPT. Associate Planner City of Tukwila Planning Department Tukwila, Washington 98188 Subject: Plan Review Geotechnical Recommendations Lot 4, Silver View Tukwila, Washington Dear Ms. Bradshaw: E- 3473 -4 We have been retained by the THB Colorado Corporation to provide an opinion letter to your office as required in the SEPA conditions for the above - referenced project relative to construction on Lot 4 in Silver View. We have conducted a general site visit of the property, and have also reviewed the amended report and supplemental report prepared by GeoEngineers, Inc. dated, respectively, March 30, 1987 and June 1, 1987. These reports summarize geotechnical considerations for development in Silver View and include recommen- dations for foundation preparation, site drainage, and other issues that are typically addressed as part of a geotechnical analysis. We have also reviewed the plot plan and house plans prepared by Crane Design dated December 16, 1987 and submitted by the owner of Lot 4 in Silver View, which we understand will be submitted to the City for a Building Permit. Based upon this review, we conclude that the geotechnical recommendations and limitations outlined in the referenced reports will be applicable to this project, and if followed appropriately, should adequately address the construction requirements for the project. We recommend that footing drains be installed around all perimeter footings and tightlined to the storm sewer, that foundations be placed on medium dense sand found about five and one -half feet below the surface, or on structural fill, and that all cuts be made in accordance with the referenced report recommendations. In order to verify that the site conditions are as anticipated in the referenced geotechnical reports, we recommend that Earth Consultants, Inc. (ECI) be retained to examine the site and footing excavations prior to placement of foundations. 1805 - 136th Place N.E., Suite 101, Bellevue, Washington 98005 222 E. 26th Street, Suite 103, P.O. Box 111744, Tacoma, Washington 98411 -9998 Bellevue (206) 643 -3780 Seattle (206) 464 -1584 Tacoma (206) 272 -6608 Ms. Moria Carr Bradshaw January 22, 1988 E- 3473 -4 Page 2 Our review recommendations and conclusion are professional opinions derived in a manner consistent with that level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. No warranty is expressed or implied. Respectfully submitted, EARTH CONSULTANTS, INC. Glen Mann, P. E. Vice- President DG /GM /kml beini-d-619144ailmi Earth Consultants, Inc. City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 (206) 433 -1800 Gary L. VanDusen, Mayor TO: FROM: DATE: SUBJECT: MEMORANDUM SILVERVIEW SUBDIVISION HOMEBUILDERS Planning Department September 22, 1987 BUILDING PERMITS As a result of the environmental review for the subdivision, the following conditions have been imposed on any development within the plat. The environ- mental file, 354 -86, is available for your review at any time and is con- sidered mandatory if you plan on building within the plat. A geotechnical engineer's letter is required for every building permit and shall indicate: 1. Whether proposed construction will require any special foundation require- ments or procedures. 2. Whether any specific on -site testing is required based on configuration of house and orientation within the lot. 3. Whether recommendations within reports on file for Silverview are adequate to address building foundation requirements for individual lots; if not the letter shall so state and another soils report or field investigation is required. Any permit issued between November 1 and May 31 will require supervision and a sign off by a licensed geotechnical engineer for all foundation work. Excerpts from the geotechnical report which relate to foundations, floor slabs and drainage are attached. MCB /co 20/SIL9 -22 THB Colorado Corporation March 30, 1987 Page 7 FOUNDATION SUPPORT We recommend that spread footings be founded in the medium dense sand or dense to hard glacially consolidated soils or on compacted structural fill placed as recommended above. We recommend a minimum width of 16 inches for continuous wall footings. Isolated spread footings should be at least 18 inches square. The minimum depth of embedment for all footings should be 18 inches. For foundations designed and constructed as recommended, an allowable bearing pressure of 2000 pounds per square foot may be used. This value applies to the total of dead and long -term live loads exclusive of the weight of the footing and any overlying backfill. This value may be increased by one -third when considering wind or seismic loads. We estimate that footing settlements will be less than 1/2 inch. We anticipate that the exposed bearing surfaces in excavations will become softened or disturbed if not carefully protected from exposure to moisture and construction activities. Therefore, we recommend that these excavations be made during periods of dry weather. If the bearing soils become softened, the disturbed soils should be excavated and replaced with structural fill compacted to at least 95 percent of the maximum dry density as determined by ASTM D -1557. FLOOR SLAB SUPPORT The sand and 'silt soils will provide satisfactory support for on -grade slabs if they are not disturbed by construction activities. Disturbed areas should be repaired in the same manner as recommended for footing excava- tions. Slabs may also be supported on structural fill placed and compacted to 95 percent of maximum dry density. We recommend that a base course layer of imported clean granular fill or clean crushed rock at Least 4 inches thick be placed to form a capillary break beneath the slab. A positive hydraulic connection should be provided on the downhill side of the resi- dences between the base course layer and the footing drain system recom- mended in a subsequent section. A vapor barrier should also be installed to minimize the potential for migration of moisture through on -grade slabs. GeoEngineers Incorporated THB Colorado- Corporation March 30, 1987 Page 8 DRAINAGE We recommend that surface runoff be directed to a storm drainage system. Concentrated runoff should be prevented from flowing down slopes below residences or driveways. This should be accomplished by providing a system of curbs, gutters and catch basins. Roof, pavement and foundation drains should be connected to a tightline disposal system. Roof and founda- tion drains should not be combined around structures. The footing drain system should consist of perforated drains installed at the outside base of the perimeter footings. These drains should consist of slotted PVC pipe surrounded by 6 inches of pea gravel wrapped in filter fabric and connected by a tightline system sloped to drain to an appropriate disposal point. A permanent subsurface drainage system may also be appropriate around -the periphery of cut areas. The extent and location of these drains can best be established during construction with the assistance of GeoEngineers' representative. These drains should be constructed in the same manner as the footing drains. PAVEMENTS Pavement subgrade areas should be prepared as described under SITE PREPARATION. The pavement subgrade soil should be compacted such that the upper 1 foot of soil attains at least 95 percent of the maximum dry density. Access roads and paved areas should be underlain by at least 6 inches of clean sand and gravel or crushed rock fill. For the expected light vehicular traffic, we recommend an asphalt concrete paving thickness of 2 inches. SLOPE STABILITY Landslides have occurred in the slope north of Slade Way where unfavor- able conditions such as steep slopes and seepage occur. Those movements have not affected this site. We did not identify any significant signs of instability on the project site. The limited area of shallow, surficial creep noted on the eastern part of the site is not considered significant as it can be controlled by site grading and drainage improvements. GeoEngineers Incorporated C F- 21 1987 P, WING GeoEngineers Incorporated (206) 746 -5200 Fax. (206) 746 -5068 2405 - 140th Ave. N.E. Bellevue, WA 98005 September. 17, 1987 THB Colorado Corporation c/o Barghausen Consulting Engineers, Inc. 6625 South 190th, Suite 102 Kent, Washington 98032 Attention: Mr. Dana Mower Gentlemen: Consulting Geotechnical Engineers and Geologists Summary Density Testing of Roadway Fill Silverview Plat Tukwila, Washington File No. 1103 -03 -1 This letter summarizes our evaluation of fill placed for 53rd Place South within the planned Silverview development in Tukwila, Washington. The fill portion of the roadway extends south from the intersection with Slade Way a distance of approximately 450 feet to a cul -de -sac in the center of the plat. The remaining roadway areas are in cut. Our services are a continuation of our involvement in the project, which included reports dated January 28, March 30 and June 1, 1987. An initial site visit was made on September 4, 1987 by one of our field engineers. Areas of cut within the roadway appear to be stable and firm. The fill, which had previously been placed to subgrade elevation, consists primarily of silty sand and sandy silt with variable amounts of gravel. We understand that the fill thickness ranges up to 7 feet. Our representative made density tests ranging from zero to four feet below the fill surface with the assistance of a backhoe provided by Thomas Construction Company. The majority of the test results indicate the fill is compacted to less than 95 percent of the maximum dry density determined in accordance with ASTM THB Colorado Corporation September 17, 1987 Page 2 D -1557. Based on the test results and our field engineer's observations, we have recommended that the upper 2 feet of fill in all but the northeast side of the cul -de -sac and adjacent to Lot 16 be removed and recompacted. Alternatively, the base course and first layer (1 -1/2 inches) of asphalt concrete can be placed at this time. The condition of the pavement should then be evaluated in the spring of 1988 for damage due to construc- tion and other traffic through the winter. Any distressed areas could then be excavated, the subgrade repaired under our monitoring, and the pavement section replaced prior to laying the final portion of the wearing course. The subgrade fill placed at that time would be tested to determine that compaction criteria are achieved. The resulting roadway section would then be considered satisfactory. We trust that this information meets your present needs. If you have any questions concerning this letter, please contact us. AefOk K. z L� F W ASti��% ` y P NCO < `: z p QisrERE� ���►�� ��eNAI EticA HRP:JKT:cs Attachments Three copies submitted cc: City of Tukwila 6200 Southcenter Blvd. Tukwila, WA 98188 l'/Attu: Ms. Moira Bradshaw Yours very truly, ineers, Ii Tuttle rincipal GeoEngineers Incorporated GeoEngineers Inc. 2405 - 140th Ave. N.E. Bellevue, WA 98005 (206) 746 -5200 FIELD REPORT File No. 110 3 -03- 1 Project: SILVFRV IE vJ DGVVLap. Date: 9/q/87 Owner: T 4-M g C. Cd_cke ADo c of .P._ Report No. t Prepared by: 4p73 Location: Tul<wlit , Arrival Time: Page: I of Purpose of Visit: E v Au-4 A -rte `4 L L Weather: CLEAR va AaNt Depart. Time: Permit No. 3- v 1 S 11. i-- t i 4&. s r-re... . - 0,1-7 /4 T f t4E /26.4e.EST 3F nw,,,Nis J (11_ isE.,.J Or TN-ev.1A C_ibIJ5Teikc.-"T ■ 'J,,,, ItJ 0R.Dr(L T - t'C Nu a L.4k.Aat. 00\0%:rT tit rt. E -- C34 t.1 ,Se i-r Tc57" 1N F 1i,... P1..,.., c.c0 1N R aek-tr? wsr, y A 4. CA 1, e r+-x. s 1 Tl'!x . Aceora r Jer)or 1-4 Pf9 r McCLc}sltGy O -r14-0e.1 et es t?()Aat441 F Lam!, , OF ARC*TCJL.. 7-14,AwI 1Z rI /A a S 11>J 0t44 Y 'r4J co Loc. tf T( 0—L1 / tit. E (stre Y w n i IQ O S 1 T E -r Jt a...n S. aT'emSlr e t r v,.J of ?. a DE t../ 'A y A-rJ D 55 R D• P L. $. A w Cr A T 14C. 4. AST 1/ ,.. i Mks. Sl, \ A L 1.. C.0 L - D E — f A L L�( .1 C7 P ST c*- 5 "b P a . ,+4 • C5 y 1-4 TA, I li l 5 141 . d 1)04'C S r4-1 A F \ L L S ■ •J E. r• `i W A -i Ala cr t,•• e- t t. Of- (Y. t.•> O ,,,v7 0-5ke-Or FOR. ,4 A 12 MA.J CL OAJ wr1T -5- 4 Ge7 - F 1L L C..1 -- I/Z is - 4,42,o0. T 4 -7' DrE-P - AceoQt;)Inl‘.? iv PAT. f ILI_ i tNI N-A1.1CI SPECI e•Ar to ,, A PPE! N a25, -r-c.) Es& 8 ac, ...]4 -r4 PA. aoc:. 13 r7.ow..,) . tc.T l cr,.)C 1A,.14 /44,1Ij SA-- -11J./ S,4.r • 17.)&'N51-1 y T'Srs i'4 Tr4c % `i(2. or A r A i e,,'r, /'t I'1 t✓ /«. A /J j / L. if /1 •5.4 ‘.) _ ? 44,i, ,1 - .. /i :3 6, C. SrioL Dr1-‘1•17. i p A /•-r(, ;r,.,)e.. "r a,3 +h 107.2. i L Id'"1,`7 Pc F L,JIr:{ M 0 us ry Ji R A• T 1 z. 3 TD ici . 2 v% .1 . -N-M-1- S C f tf.E (-‘, V1/44 C D, u w~ 37' 147:-P. i a 4-i- A a i7 / M [ , a ..,. ;;) C„is tz_ - T 1 L.1. P 1 /i C l.". iJ 1,-,1 OE ' /?: lam c d.( b - .V ti - 5 A t::_ t.r A ,a c` C 41I't) :.,l 'j T 3 PA, 7. /d• 1 Q,.s.. -{ 4 0"I' F,: f;" . 1-1 A aI() - -- - (,kC/JS c ft l L S f)o. --vE, f v1 A. t F R 1,1 L- 12 /3_ rJL, i .J 67 F ; i 00-4- s ;1.1 f' ',it:: - IA-1 C / c, ,iA IS '41'."_.) / , y \.,lCF`r /.ib:pLi l( LL 7. ) Tu ri NA k,}4.-. ac aJLT/ FI,JE 5 Ar1 Ani(1 5 ,i.,J(i/ S e L T_ DFt-15177 TO -S7 S A ! H E r2 o#+A, -.1 A ,-../ Sv B c- a eNAV C 4 ',X - 10 fr, \X tsf c. IC.L YtnA 6.-2,rQ (.Sl V A(1r $4 ,31.ii ac su <r p..JF f A-10 9 A a..1 G1Cv F k? A -A. I I3 .' To 12'7.7 Pc F _ TrSTS ss -r --1 V -2- / ,4_,.., D — Z F Q o a.t 5 u8 C, D. S-4-i . Jr e, O e-J 5 tT (f 5 oi- t O iI- To I b a PC_ F w 17 4 M. ens T.r -i✓Z0 ,4 7 ASOUT ZO2,- , . f'tLL AperAp41 (m inn.) bk &Ise I/ MGD 51--)FE, wP2 TA -W-rsj e(L0...4 TI. 57 A//CA5 A8 0*E. -1—t-4 2f.E- 6uIK SA,NPLC i 0, FILL This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering. We rely on the contractor to comply with the plans ands ifications throughout the duration of the project Irrespective of the presence of our representative. Our work does not include supervision or direction of the actual of the contractor, his el ployees or agents. Our firm will not be responsible for Job or site safety on this project. Attachments: Distribution: Signed`,' GE1 70. PROJECT T+1 CO± 024A O C35)42-1', S' V E32 EZ uJ FILE NO. 1iC53 --65'1 SHEET ) OF 0 T 3 4 1 SUMMARY OF IN -PLACL AUSTURE AND DENSITY TESTS TEST NUMBER 4 5 7 TEST DATE TEST t•IETHOD FEET TYPE FIELD GENERAL ELEV. SOIL $ LOCATION (FEET) IQ TO TYPE COM- MOIST. OMC RA PACTOR E 51,1j E Cu.L- DE -.4G (I Sc.c�c"? VI 1 -8 C). 5 -r 5 \f L,.3 . 121.43 NF 5,DF E cup -ve - sA C_- DRY DENSITY (PCF) 4 COMPACTION FIELD MAX. _FIELD SPEC. 113..3 • -124.0 89.9 1'15 IJ S i'E_ F CIL- DP-s .4L. O 2 f -K,s v/ F sr--)F• - 5-4 C.� 1< /rots n se-c � E r��L- DC - - 2 5: Imo; 5 la-r.-7 7loo 4S gs v 1 G .13 1 ' l ., 5, I;` 5 v 2o.6 Rb' S of J,.-nrg . onl 53 J . PL. . - 57)'s 2'0JiTR. OJ53 D• Oa_• Gi 104_3 BS 19 .2 108,4- 4ti_6 40 qS . )b?.Z, /24.; 15,3 1O7 -2 L2.3 1D7.7 94.1 90 9S q5 PERCENT COMPACTION BASED ON: 05jANDARD PROCTOR(AASHTO T 99 -57, ASTM D 698) MODIFIED PROCTOR(AASHTO T 180 -57, ASTM D 1557) DENSITY TESTMIiTMOD N - NUCLEAR (ASTM D 2922) SC - SAND CONE (ASTM D 1556) RB - RUBBER BALLOON (ASTM D 3167) SOIL TYPE S - SAND G - GRAVEL Si - SILT C - CLAY s 8 si c - sandy - gravelly - silty - clayey TYPE OF COMPACTOR R - RUBBER -TIRED ROLLER V - VIBRATORY COMPACTOR S - SHEEPSFOOT ROLLER GO - GRID ROLLER L - LOADED SCRAPER JJ - JUMPING JACK BV - BACKHOE VIBRATORY PLATE VP - VIBRATORY PLATE HT - HAND TAMPER ABBREVIATIONS OMC - OPTIMUM MOISTURE CONTENT RT - RETEST OF AN AREA Si - SLIGHTLY GeoEngineers Inc. 2405 - 140th Ave. N.E. Bellevue, WA 98005 (206) 746 -5200 FIELD REPORT File No. 103 -03- 1 Project: SIt_vEnsv vev6 t. o T.1r Date: 91 to 1B-7 Owner: '114B Cot-ow-Apo C.017.-PoTLA -nor.) Report No. 2- Prepared by: Jd-I►J B SEL -Les- t 5 Location: `fuKwtt.t.A Arrival Time: rt :00 Page: 1 of '_-- Purpose of Visit: D N,ITy TEST/r. Weather: CLSAr� WArtr Depart. Time: II :30 Permit No. A S1-r j VIbrr wAS w..4.06- TI4is wv,a -i∎ itVrr AT -l—E Hats.vf°ssr ot`' 'DANA Mow . wrn.4 •AR (- f- (0.1,S43J £w1 G1N =omfLS To gr12-17.1z -.,r. a,D airs niAI-- 13a•ur5r - -C=+ l . A I..nn1G 53 Pta G8 Sri irt-t . -rs -re EvA t -L �- go e.rx.v➢ty APprzz c1 V rrrvLy G. llac.4 -t~S ea= 31li{ IKICM. wn,►.mVS CfLL/S4 -tArD k. HAS R% .: -s n1 PL AL.---AN Ai\ JD t -ys .PAr -rE,D P12.■02 -r, rift d/Lt2t /AL.`Tb - Srro . A SACKI-kinG. WAS PrtbVtDF.D RY`-Tr,.-n Co.. nz.Aa- re-sft ---r Fa( co.' -r -/-=c-r" ? 2- FaTLw, TIOk cr- y -TESTS 1-4ot-t- -s L.Jt t w1- t, ,-►t To 5 3 Ilse Pic c otrr. -r Fr.Tr¢ti.r../ [..E-, - Kano t.,.ny P. w OLZTA c-Grra r Tri 71+ey n_ 12 -It.. CA-4.---S re m-% PACZar.1 yvt•trt 'Rln 1- y,/A S Dirt. t,..,w/ FA.Trr7-r117■ .r C.E -TO t-cr-r z l.IA.S Te:Sir.�3D Ptn/i4t sv61 De c4,P!A.AA'TCaw1. UPPER- 2 T=r 1- Or Tp 367 - it./C. -tOS egyNA -T y 6 F-r1 -tt w1 t LI pt - 1 ts \ -rr4 -ra 1? P -t 7.Z '/ Ar..w 77 l pT 3 raa-T- f3 =1 Lt.l -1c+" pxn,.Ir Stir .C...E V.--iLF61 -r rwo C- , Cc-- , pi4 fiTi a r.1 LS Fov6..cl--I5 R $ 3 4 _ At! _- Pito c.acb v¢�5 Ft72. 1 N - P t-oa r.a ae'�.1S raj TenCS t_k/E17..>1 C � e3D AND 110Vi2t.E 1 Nrin - 5-t,=y Qli - Ca teT AS t LJ_ As I' jP v u G- IP .NGF-+- cifi-Laa-T:.-11(5N /0 e"ArZ I..Ar4 -f C...sav6- - -. 5 3 t- • . __ - 4— 1. - - - 1 - • -.. ' _ . - la•_ a m L. ._-. IL.. _• trr , )t.1.2 'iivcrr 0t 120.1 1St-+ S1.4?„!--TZ c a- (RYvk P/CT7 r rip---n-t- pY1.CrTb —rein 1 r A D-T.gttATt Tr, Lo-r- 1 f EtSTr2.ta ti r 12n,.1(..-EM 3. ��t+ 1 4 5 `/ Ar,10 `j% °/m rY1rw.....lz- AFLt t. t A-1 --n-t t 4-tYryt • •r_ or u - • 1 D 0 INS .1. r -1F-1-.-- C . tea. lr nr.rjs 5. 1r.1cZ7r�YY\ _a. ....72•E6.+11. a -• a -• S _. -I-05'T w.ts S Rmrt rtwvr /AT r- - sr -rte t-c r- - C • - . f • - ■ 1-a_Ar - a_ - r . - .... ?12o. __n . A AC.I.aS► =-D AT' IA -IN Cl-t 22 qKrrrz.dr.)r;w rte . F,r.1 t -t S ecwf21Af (e✓�. Pn GT3rL 6 Wc 1'- at a r� This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering. We rely on the contractor to comply with the plans and specifications throughout the duration of the project Irrespective of the presence of our representative. Our work does not Include supervision or direction of the actual work of the contractor, his employees or agents. Our firm will not be responsible for job or site safety on this project. Attachments: Distribution: Sinned. GeoEngineers Inc. 2405 - 140th Ave. N.E. Bellevue, WA 98005 (206) 206 746 5200 FIELD REPORT File No. 1103-0-5-, Project: 51 �vs Tt.,yI �w Davao �prvvri rr Date: 9 X10 �$� Owner: Tr( 13 co(,OR/ADo co 11- Parl.ATron) Report No. Z Prepared by: .JohN s . S6 L.1_ortS Location: 11.) K'-" Page: z of Z Purpose of Visit: ArvNS••-ni T ,5-riNJG- Weather: C1-6AIL, WA1i.r- Permit No. Z t•.1Ip2j' 1 O r4A -INn -r 1 r. ., L_ -re -SA c. AREA APP6p2S -lb 11 AV$ T{.•- GE ./ ED A r).= .NvArrki r»vv,RAGT1a f.1 Er- Fete -Tr tn1 Pt LA-- MArr. 12.Aa .. PL.r u r� 1S'S f_14.5*-ii A"24./G -E , }{6„f�vlxrL, T i - neua rai2.A t... ,'Y -Tri OnrritdN C. tr 5 3 t`—°- Pt-AcF S'nv-r. -t ts' w zSc. A ND "j'`eS1 n/ C,,- 1tvDt(....rE 1-0 SCst CQyv5PA(7, -, rhArtZRiAt- TtiP-ovrrfi0trr ! 1).c. nt A_ /ES-r-Af> - 11-twr "r )^ r ?_w,,1 id .c LA In& r-rS r - n-i..z C-eoSO 'r--ti W►a- (z-n_..01 L. PrLL n-1_ --to i vu.J __. Str. - iid■E. L,oOS4. MAT. 17_4 ita L. G6n1C 1 S --Cs ex: A 1?-12,i i,.I .Si I ^...ts-j ViI.1.— SAt tp Lirn- occA.S.oNOi. ar-11..es VEIL- a..,a 14-5"--T5 . -Titer. rwt:t- ■ t 4,0.0 ciVrv0 ut,J1?.rel? ' -, p ele.HA. sr 13.6._snc+ Caas Te rvt, a-C 17-0:1 1... 1A -2.42.r..., 53 1= PL.AC 6 ,5nrcift .. .•a.• _. o.•_ .O a . .../� • - 1 • Ca"• •• • L PL.,01 C I s■l a e S op V n1 tU+1QWr - •ji•t, 444N E :5 vha•f .17-aJa H a5 a ,.1 otrclZ .-S•rr.... fl 1,..A.- w 1. 1-L - C.vt.- -P—SA c faa -A .A3:23-ncNrr -r (ro-rS 17 pnJD IS df.nJ� R — c,,tv�. Ft •-t- 13 a--r,,,), 1J &V.acr 4-S 2547 n,./t Z'fo fu-k- Ini,A HAuc 3==t`1 -LA Th •F2n -v,- °�3 , f £ r rte-, S---t- - .. . -- to - 1 ■/f • r . . • LA.. . -Ass _ .. • . -1 • - - . • t c- —�� CI_•,.• : . —.— ■ a ib Ell C F,Is�t- �rrn -t v N G- • L/► - • Z I:, 6,0 R.aM 6 VEsiP ANA ' - r,n,.,.Poc ,:us - rapt- I^t is 13 OS-Ja.rs 1 E L- -12r�D ZP_.� l5 A lirr iLTCiA l_ �• :r i. Oh - X112_ gtJ`dM. ypt.5--Tr2...0=--Ss _ This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering. We rely on the contractor to comply with the plans and specifications throughout the duration of the project irrespective of the presence of our representative. Our work does not include supervision or direction of the actual work of the contractor, his employees or agents. Our firm will not be responsible for job or site safely on this project. Attachments: Distribution: Signed -,ez" PROJECT Sw6vI &' FILE NO. ►►03 -o3 —, SHEET i OF; s.ieeuI6u3oeO SUMMARY OF IN -PLACE MOISTURE AND DENSITY TESTS TEST NUMBER TEST TEST DATE METHOD GENERAL LOCATION FEET TYPE FIELD ELEV. TO SOIL COM- MOIST. (FEET) GRADE TYPE PACTOR $ OMC DRY DENSITY % COMPACTION (PCF) FIELD MAX. FIELD SPEC. 91/ 0 1\\ 10°N ., Lor22 D2 € Ad— P g'w of cwt.. ran, } s.s V 141.3 } Iz.7 Z 142 96.2 474.3 77 95 93.9 t 76 �. g$ 9. 7-z �.. 3 5 o1i( E ftruo4Ct 20 w Car /4 Cm- RANG". 12 Z 5'".+0s c,42.3.45 IWy 13.'7 103.2 1 - 83 90 119.8 I zC..o 5 95 1'23.90 9S, y 15 96 -4 __I2y.3 _ 7$ qs Z 0 r > n rn 0 c rn z v 0 rn Z -c —4 —4 PERCENT COMPACTION BASED ON: ❑ STANDARD PROCTOR (AASHTO T 99 -57, ASTM D 698) 94MODIFIED PROCTOR (AASHTO T 180 -57, ASTM D 1557) TYPE OF COMPACTOR ABBREVIATIONS DENSITY TEST METHOD N - NUCLEAR (ASTM 0 2922) SC - SAND CONE (ASTM D 1556) RB - RUBBER BALLOON (ASTM D 3167) SOIL TYPE S - SAND G - GRAVEL Si - SILT C - CLAY s - sandy g - gravelly si - silty c - clayey R - RUBBER -TIRED ROLLER ✓ - VIBRATORY COMPACTOR S - SHEEPSFOOT ROLLER GD - GRID ROLLER L - LOADED SCRAPER JJ - JUMPING JACK BV - BACKHOE VIBRATORY PLATE VP '- VIBRATORY PLATE HT - HAND TAMPER OMC - OPTIMUM MOISTURE CONTENT RT - RETEST OF AN AREA S1 - SLIGHTLY . E1 15 1987 CITY 01-- Pi Ahti\HNG LEPT. GeoEngineers Incorporated (206) 746 -5200 Fax. (206) 746 -5068 2405 - 140th Ave. N.E. Bellevue, WA 98005 September 14, 1987 THB Colorado Corporation c/o Barghausen Consulting Engineers, Inc. 6625 South 190th, Suite 102 Kent, Washington 98032 Attention: Mr. Dana Mower Gentlemen: Consulting Geotechnical Engineers and Geologists Summary Density Testing of Roadway Fill Silverview Plat Tukwila, Washington File No. 1103 -03 -1 This letter summarizes our evaluation of fill placed for 53rd Place South within the planned Silverview development in Tukwila, Washington. The fill portion of the roadway extends south from the intersection with Slade Way a distance of approximately 450 feet to a cul -de -sac in the center of the plat. Our services are a continuation of our involvement in the project, which included reports dated January 28, March 30 and June 1, 1987. An initial site visit was made on September 4, 1987 by one of our field engineers. The fill, which had previously been placed to subgrade elevation, consists primarily of silty sand and sandy silt with variable amounts of gravel. We understand that the fill thickness ranges up to 7 feet. Our representative made density tests at various depths below the fill surface with the assistance of a backhoe provided by Thomas Construction Company. The test results indicate that, in general, the fill was compacted below 95 percent of the maximum dry density determined in accordance with ASTM D -1557. Based on the test results and our field engineer's observations, we recommended that the upper 2 feet of fill be removed and recompacted, as discussed with you on September 9, 1987. You indicated that leaving the fill in place without recompaction, with the THB Colorado Corporation September 14, 1987 Page 2 resulting potential for pavement distress caused by fill settlement, was acceptable since the final lift of paving will not be placed until spring of 1988. Any distress which develops during the winter season can be repaired prior to final paving. Additional density tests were made at your request on September 10, 1987. These tests generally confirmed our earlier findings. Test results and daily field reports prepared by our field engineers are attached. We trust that this information meets your present needs. If you have any questions concerning this letter, please contact us. t (fie' � �`' TUTT� _` Yours very truly, `4 >G of �Ac� + `` i Geo veers, Inc. ,. r■ ■ A!.... 12 %. orF 9f Gis E ,�` ti f, P — ncipaluttle HRP:JKT:cs Attachments Three copies submitted cc: City of Tukwila 6200 Southcenter Blvd. Tukwila, WA 98188 Attn: Ms. Moira Bradshaw GeoEngineers Incorporated . • GeoEngineers Inca 2405 - 140th Ave. N.E. Bellevue, .WA 98005 ' (206) 746 -5200. FIELD REPORT File No. 1103. -4. - Project: St L VERY te. v.) Pc VE Lop. Date: 91'1 /87. Owner: • T t+ B c a-a2 a-DO c ©2 -P,_ Report No. 1 Prepared by: 4'013 Location: . Tta,tw)1_it- Arrival Time: Page: 1 of 1 Purpose of Visit: .ga^t .iq..-rE. ' 'ILL: Weather: GLF„aR• ..wila0A Depart. Time: Permit No. i J'S tt _D TNT-. StTt_ 't- tlCAi -`j 1 4 i TNE. X6:.(01.IFSt )F (-)E.t.)NtS t1._L[tSB.n1 .Tia -o,.....,Rs G�as-C'd�‘tc,r)W., 1 N O it- DC!2. -L-K1 'r- -&x. AAc.LcAR P'OLST...t aE. — DedserY •TC s'T3 1n./ iF 14- ` FL A.CVIN t.P1 R aAD wA44 AdZ..C.A' S «- r+ie sorer. . Pre "A0/Nleir 7'11 PAT VA C L.CAtetJy Og TW6y. A, S. , 12G Ab i4' €0t1-5 0 F efi'R.C.kTC.A... "r“."....1 12_ " A 4.e_ kJ V(.11....f % o L.oc.0 To o45 : TNL cw-e6',( w A `(. - -n.tro . S i T it. c Ito t'J\ S n!TC4 $C e T t tvrJ GF. T 4 A DE ....rA'l A-J D -55 RD . P t.. S. 4$ 0 A T T G A. S" ". t/ ,IL. GFr r Nit. rt.n A L L .Cu t` — D E — SAL ►..0 C:Otte 7 C. V A rsT OF- 3 "J a O • gyp{,,, • a y 4.) T .2h 11, 18 • 1`i . Poo-‘ S .(4.-( o c.` t_ s 1 a E. fJ r t s y .,,c o, sy A w. V_ c e-. f'Z.. dc- re tJ+> C. wr7l 6 V.,e- re r F-o R. 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Tc A n.tvs. 6F SILT,/ Ft JE' 5A.4.0 A4 ^I l0 5Ac..rD7 5ELT- DFtJSCry -t LS A 7 1-HE 2o34A‘-.IAA( SvBC.a.q[6 &A Jr f To M K 6f c r c. +-1.4 er.42 to L. v A rz ,, L r a C 504 t-r s P.a A -00 RArJ(..cts F'Qa..i. 113 -'3 To 12 -1•-7 PC .F _ Tr :ST-S A7 _-1 V--2- .4N O - Z r V 2 o r.A S u /3 C, D. 5* o...i>;..d) D.a 5 (T t {` 5 og t O 4- To t 6 gj Pe-4 w 1744- hots cs TWL AT ABou.T &O% . c(LL A- PPCAPfCi Mr D. Di- I-ISC /MED. ,STIFF TNaf£- BULK 5AMpLC 5 0j SILL wCac T4-W£w3 F z.c.& ME 57 AaaC45 A6ettE. This report presents opinions formed as a result of our observation of activities relating to geotechnical engineering. We rely on the contractor to comply with the plans and throughout the duration of the protect Irrespective of the presence of our representative. Our work does not Include supervision or direction of the actual work of the contractor, his agents. Our firm will not be responsible for lob of site safety on this protect. Attachments: Distribution: Signed ficatlons sor GE1 70 , P R OJ E C T T4 L t-OQ A O e' *?, (SI \.V 0 FILE NO. iK -'ff-\ SHEET ) OF sJgaulbu3oeo SUMMARY OF IN- PLACE_.f J%TURE AND DENSITY TESTS TEST TEST TEST NUMBER DATE METHOD 4 5 7 N WilhadohAiNfr TYPE GENERAL ELEV. FEET SOIL COM- LOCATION (FEET)& RADE TYPE FACTOR E 5 6) E E Cu. L- D E -S,4 -C r) +$ C c; f Ni n1F 5eDa- E ca c, -oe - sA C- - . O. 5 i'1.7--M$ V A) F4 S of, E Gut—Dr-SAL 0 FP1$. \/ F SQor_ F. Cu! -de- -2- F; 5 . E ,$t/)r- E rrrL -DC -.s - —1 S('c` t�s aF_74)11-' • ON Si ¢p ,L s Rar S of 1NT . - I S,`4 '5 FIELD , MOIST. OMC % 1-8 113.:3 -11/2 (0:0 A44, 15'.. 6,.3 121.6 -,.-Qks. Co-4._ .. `.,1. 1..7 ` 7100 I DRY DENSITY (PCF) 4 COMPACTION FIELD, MAX. FIELD SPEC. 4o. qs 9s 90 9S I53' 51 '5 e 1 J7 P O&15'3 FL- a c51 4 Left . 2- )24.1 4- 9F; 2: R6.2 ... 1n7.2 /D7.7 90 9S 45 AIL 3an1S I Ow 3Ddld -NI A PERCENT COMPACTION BASED ON: Q ST DARD MODIFIED DENSITY TEST ,METHOD N - NUCLEAR (ASTM D 2922) SC - SAND CONE (ASTM D 1556) RB - RUBBER BALLOON (ASTM D 3167) SOIL TYPE . S - SAND G - GRAVEL Si - SILT C - CLAY s sandy g - gravelly si - silty c - clayey PROCTOR(AASHTO T 99-57, ASTM D 698) PROCTOR(AASMTO T 180 -57, ASTM TYPE OF COMPACTOR R - RUBBER -TIRED ROLLER V - VIBRATORY COMPACTOR S - SHEEPSFOOT ROLLER GD - GRID ROLLER L - LOADED SCRAPER JJ - JUMPING JACK BV - BACKHOE VIBRATORY PLATE VP - VIBRATORY PLATE HT - HAND TAMPER 0 1557) ABBREVIATIONS OMC - OPTIMUM MOISTURE CONTENT RT - RETEST OF AN AREA Si - SLIGHTLY GeoEngineers Inc. 2405.- 140th Ave. N.E. Bellevue, WA 98005 (206) 746 -5200 FIELD REPORT File No. 1103 -03- 1 Project: ...511yErkut4I..7'Dev6t -o?r Date: 91 so 187 Owner: in-t8 CoLoRADO CoR.POR., na,.) Report No. 2- Prepared by: Sow0.5 II, SEt.t..6tz5 Location: 'fukwti -t.,A Arrival Time: 1:00 Page: 1 of :- Purpose of Visit: 1 .f'JS I Ty TE-ST1 ••JG- Weather: Cuasiarz., twwtt.rvt Depart. Time: 11:30 Permit No. A Stt.a 1rlSrr ‘../AS tin.6.0.6. T141 trvtng-nim.)Cr Ai- -n-tE • RG[a)ves-r o-• t•nowGr— wt -m4 SArCt Hl.ustrN Sma4,.t,cmimaS -ro. 'F e., ADQATTA.ua-.'Dr S1"gt - 71=is--rS -rt. EvA u /A'r - Ro eatxw.sti 't- i 1 _ At.. 3b t - 53 Pus cc:). Sit ii-r -t . APPRzaunnalst r y G twtc 4. alt= `t t,,,1.0 trini,m s CrtLS4 {Arr) d-lag ksas •:J -!. • _ . • •... - • ..t.. �• • r Ir. A. • t r _ t• 1_. - A EAC1C14r3 t•,A-S P1 L VII FD Ry -71F-tt C.._,.,•rA.,...rtaft •-iz Eacr..4. rr -L-�t- .cif - ' -. _ .• - *•1r. .11 • .. • - . •• . 5 3 x---4,7- Pi.,oc S otrrr -t Er.Tr2 .)r - 'Koant.,,ny Ft car Amesr,.0+.f- T- —is+� • cricrea 1,7--mit-1-4.-S .• •a c J. To 3ln - 4,$C.4-t.S f-r? ctsizp-7 s t=tr.) * -4 Sti6a-aAaE St.-Frt.r++ccfcsf+l. a p--rI-t6 w►trt{ ate 1•,‘ -t-r-t a VPPaR- 2-V-,-.2.--r aP C, ry PAC- Tta[.A 126A-r-.7-1A4- 1,,ie C F) xn,an -ta 72 % 77 % 3 re —r— R =tom - '+ S.A c.E 1-4, A•.w f p-r cezvtpAC>rta.J Lvatbs Pcivk -c1- a R,.. 43 K - Aft PPftococtrtAR S ?62 "Pcriz %art4. 1roC- trI- Pt..ACS 3- I,as raj -TreiSrS wB la r,r.► wiSD Ar.if Dtpirkt-6...- (- acs-z•Ki) AS- t .1_. PS INIPtrrT.uG - A -7R 4+ c.oj 'T.�T' r- trm- rn -rft r.tt.Ei �ptz- j7)1_wKCr•v7 C-Av& - 5 3 a--. PL.p cc- Sour► -c L.0 L.. -DE. - So C.- - Zwo DJ& Cr fl - f=S-TS' '-- - Perz•patz..ne'3D f99- rent: U t A-r n•.,.a Thr -rd= 'PIM IC1-4- St.R.rrzp rrrwt pA cflr Q rrT4[�f.Tr r- , Elf • C • .- • - e c!n Q A•.II� I A e( - --- ..-': • t 5 Uda■AA rYtrn..�Gtz 15.11- 2■■.CD AT--tF4 <L-r-= nr.,n I.., RIri. 4-ttorn c 7W - - • =- . .. r -r 1 t . (? i ' _.. ...Aril In --r*tc -r C P -17-g P Dahl. So -ri-t - 'tkE crud! D ot9Sc -i/sr IF1— r-11 AT 1�5 -W fh't�5 f � ' ► R- �(l,W1 # r? r 0ze gaC - A Ac►PJSL- yrP�T" Mow. PI N tS►-t St sC 41 / 44Txsd1 3 -m Larr- 22- t- i11-241►..,j . ezkrrk Pea t .-,N1 '-$ r-rt ✓nA ->a $ 78 % . This report presents opinions formed as • result of OW observation of activities relating to geotechnical engineering. We rely on the contractor to comply with the plans and specifications throughout the duration of the project Irrespective of the presence of our representative. Our work does not include supervision or direction of the actual work of the contractor, his employeee or agents. Our firm will not be responsible for job or site safety on this project. Attachments: Distribution: Signed. GeoEngineers Inc. 2405 - 140th Ave. N.E. Bellevue, WA 98005 (206) 746 -5200 FIELD REPORT File No. 1103 -o3 -► Project: 511- vcrtvt> D,svtra.opr.%c„rT Date: 9 j1 o 187 Owner: IN IS Cot,aRAt CoR- ParisaTioN Report No. Z Prepared by: ...7o Ht.) 8- ScLA -4 is Location: ZUKw14.-1-A Page: 2- Of ? Purpose .of Visit: DWJSr-tNy T65TlNC,- Weather: CuzAii, WAILw1 Permit No. •1 l..,ForrMCn ytraJA--TP1e- r-T-be r-Lt L. -DF. -SAo AR FA APPF"p2S To 1 M Avg T > : P : C F . t J E o Ano n X . > A - r . CmvLpAGT1c r 4 Gl=.9,PTS PfN %;L4 — MAY ^"r' "^ - Al.nn16i 11'5 EAS-[¢n '117- 41rr.- ., i ,ervesrz,--TltFr. r-it_A-- rYlgrr 124AL. ,1-r 'n 4, . W n T 1tAn! L - F b 5 3.11 P i - A r J O - S e t rri-4 tS t.csC■ AND —r - N t'r pa r7ro -I? rmorall-IAL. T i2Avfsr- 0v-r- 1r-01C -r I.OQS ow/ Caret Dp144+ Basl.IeC-r=1"? 714A-r -r -n-ta L-4••,-rS rip "r1-1,0 LetoSB I tt NN1.4w- (7=•R.41 _ _D?-rErz.w.i1.I.S. Pr24 nrL. -to Lira:. vi j.J G---11-)02, crr..V__. - -11-1,1W l.00Se• C r ■_. .0 . ■it - - _ .. - - •• =r_. - .. e- i. . tirt,s vss- A 'RestrI S -r3 t..� tin 7. r-avr.m u a CKA . ..ID j'%NISFirt el&S" " CQAZ.K t." L i ✓!+S 4' rn, j7�i.gork7.44% , 5 ille /74-AC-.6. g•^ -11-t •R✓n-% fl 1-ti uSN E S ri.r- ris",sr r.. Sov-rFF E O a -r 4si. -r1-t or- t 3 A R tFrim A PT [.t-'D Ir., 1.'i2 -ot or= ti hr kct.i ./r - rtiP. L i --n-i&-.- G/i- -1:*-5AG AR A AztrOC.,-/\Tf r Y,jye■- Ljja - -$ AS Bea 'P1-•. o,rGZ. /71,1 iS-r f . - w i -t-el LQ -(• S 17 J1 w1 D I S i tA•/. R -c..a .0 G1 Fi.- R Ez- a.✓ar,,r -O t.1 Q1..Ea AI% 0 n4S 25a ‘1,,47 2. ye fu L,t, ervly H,nl rG r,.) 'fl -d£�Im frt+rr - 33 R52 / 'i-sz C4C erS t-pr., L*: So.rr -r as f-F� T_ \/se ...- 'PEr.t .,r.a�.PC:.D - t.o-T' "jr-{p fi -j1t r.ir g. r, v.-t .. - it., p r- ,.Tii24 t , F,, MANIVIE3rZ M Aril = -I L_ $ F R.ary,6V1:gD AND 'j pt_pr_aD f fir CiTysn pp r � 1•-1 Cr (4p ^' i rack. ,ate j�L�n Pi 1 rrC-t 1.----5 -Zr, 1 0 1 t,rc -t.,S -• ,rt.. OLsJr . l7 ijQS %"-C.i1;:lsOQ -lb V[Ilrr gat) Lw.rr -f 1/4 vin, G-- 4ND VivA STA1.4S - -ir-ha .0 _ 1S A f „srrA L- T612.. r?A1Je%h'1 T piS -1tL SS - This report presents opinions formed as a result o1 our observation of activities relating to geotechmcal engineering. We rely on the contractor to comply with the plans and specifications throughout the duration of the project Irrespective of the presence of our representative. Our work does not include supervision or direction of the actual work of the contractor, his employees or agents. Our Ilrm will not be responsible for job or site safety on this project. Attachments: Distribution: Signed• PROJECT 51 vJGRAA V el.=Pm et-'r FILE NO. I) 3 -o3 -/ SHEET / OF SUMMARY OF IN -PLACE MOISTURE AND DENSITY TESTS TEST NUMBER TEST DATE TEST METHOD GENERAL LOCATION ELEV. (FEET) FEET SOIL TYPE FIELD TO TYPE COM- MOIST. GRADE PACTOR % DRY DENSITY % COMPACTION % '- (PCF) OMC FIELD MAX. FIELD SPEC. Y S 9IIo 101N nF Lor22 PRA*. ANC. WOFG., 13, i S'S rj 7 1.c1-I f&TLIWJC.G Z0 w cdr /(o 4N{iZANCr 5".JO:cvaa45N foist -I. z. 3 96.z 93.q 69.8 (o3,1- 119.8 13,'7 171(.3 _ 77 95 76 11 e3 y Yo I zC,.o 95 55 123.9 96 -9 12Y, 3 9s.y 9s 7$ Ts OW 30V1d-N SN3O aNV 3?1f11 S PERCENT COMPACTION BASED ON: ❑STANDARD PROCTOR (AASHTO T 99 -57, ASTM D 698) ('MODIFIED PROCTOR (AASHTO T 180 -57, ASTM 0 1557) DENSITY TEST METHOD N - NUCLEAR (ASTM D 2922) SC - SAND CONE (ASTM D 1556) RB - RUBBER BALLOON (ASTM D 3167) SOIL TYPE S - SAND G - GRAVEL Si - SILT C - CLAY s - sandy g - gravelly si - silty c - clayey TYPE OF COMPACTOR R V S GD L JJ BV VP HT - RUBBER -TIRED ROLLER - VIBRATORY COMPACTOR - SHEEPSFOOT ROLLER - GRID ROLLER - LOADED SCRAPER - JUMPING JACK - BACKHOE VIBRATORY PLATE VIBRATORY PLATE - HAND TAMPER ABBREVIATIONS OMC - OPTIMUM MOISTURE CONTENT RT - RETEST OF AN AREA Si - SLIGHTLY Earth Consultants Inc. Geotechnical Engineers, Geologists t! Environmental Scientists August 31, 1987 City of Tukwila Planning Department 6200 Southcenter Boulevard Tukwila, Washington 98188 Attention: Moira Carr Bradshaw Subject: EPIC 354 -86 Silverview Subdivision Dear Moira: E -3473 l�lil {1 \ij15 ._ • Lt.21987 1 CITY Or TUICvviLA PLANNii''3G As you are undoubtedly aware, THB Colorado Corporation has elected to utilize the services of Earth Consultants, Inc. (ECI) to provide geotechnical consultation services to the referenced project.. Our involvement on the project follows completion of several geotechnical engineering studies and reports by Geo Engineers which provided recommendations concerning site preparation, foundation design, drainage and other site development considerations. At the present time, and in preparation for our involvement on the project, Earth Consultants, Inc. engineering staff has completed a preliminary review of the Geo Engineers reports. In addition, representatives of our firm visited the project site for a brief overview with Mr. Thomas Barghausen in late July, 1987. For our future involvement on the project, ECI will conduct various inspections,and reports in a manner which is consistent with the recommendations and conclusions of the various soils engineering reports prepared prior to this writing by Geo Engineers, Inc. We trust that this letter will serve as an adequate indication with respect to our future work on the project. if you have any questions or we may be of service, please do not hesitate to contact us. CC: Barghausen Engineers Respectfully submitted, K4RTH CONSULTANTS, INC. Don W. Spence Hyd 4geologist �// G,� GRobe t S.�Levinson, P.E. President , M.Sc. 1805 - 136th Place N.E., Suite 101, Bellevue, Washington 98005 Bellevue (206) 643 -3780 Seattle (206) 464 -1584 222 E. 26th Street, Suite 103, P.O. Box 111744, Tacoma, Washington 98411-9998 Tacoma (206)272 -6608 City of Tukwila PLANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila, Washington 98188 (206) 433 -1849 August 13, 1987 Thomas Barghausen 6625 South 190th #102 Kent, WA 98032 RE:. EPIC 354 -86 SILVERVIEW SUBDIVISION Dear Tom: This letter is in reference letter that the engineer of record Engineers to Earth Consultants, Inc. The City would like to have a letter from Earth Consultants that they have reviewed the environmental soils investigations and reports produced by GEO Engineers and that their inspections and follow -up reports will be conducted and produced in accordance with the reports' conclusions and recommendations. In addition, the enclosed letter and conditions from the Public Works Department must be followed by the new soils engineer. Please note the last paragraph of the letter. The letter of acknowledgement from Earth Consultants should be in our office as soon as possible as we assume they have already assumed their responsibilities. The final plat cannot be signed until we have this letter. Sincerely, Moira Carr Bradshaw Enc. cc: Phil Fraser, Public Works Dept. -,Duane Griffin, Building Official BARGHAUSEN CONSULTING ENGINEERS, INC. "Land Planning, Survey, and Design Specialists" July 30, 1987 Ms. Moira Bradshaw Associate Planner Planning Department City of Tukwila 6200 Southcenter Boulevard Tukwila, WA 98188 Re: Change in the Project Soils Consultant for Silver View Our Job No. 2262 Dear Moira: 11 r.Ur -4. 1987 j CITY Ui= TJKv_iLA PLANNING DEPT. Now that we are proceeding with the construction of the above - referenced project, we have reached a contractual agreement with Earth Consultants, Inc., to provide the necessary soil testing services during the construction phase of the project and to provide the follow up recommendation letters and soil test, as necessary, relative to final building permit applications on each lot. We were not able to successfully negotiate a contract With GeoEngineers Inc. for the remaining work on the project, and we want to notify your office that the engineer of record for this project in the future will be Earth Consultants, Inc., which is a fully qualified geotechnical.firm with extensive experience in this type of -Work. We will still be utilizing the soils information already prepared for this project by GeoEngineers Inc., and the SEPA conditions will still be met through our design and permit process. We expect to have a number of . builders making individual site applica- tion to the City of Tukwila in the near future, and Earth Consultants, Inc., will be coordinating the individual recommendation letters and soil test as needed. Would you please proceed to review this information and let me know if you have any questions or comments. You should also notify your Building Department of this change in the registered engineer for the project. Thank you. Respectfully, Thomas A. Barghausen, P.E. President TAB /sm C263.71 cc: Mr. Dana B. Mower, Barghausen Consulting Engineers, Inc. Mr. Donald Spencer, Earth Consultants, Inc. 6625 South 190th, #102 • Kent, Washington 98032 • (206) 872 -5522 BARGHAUSEN CONSULTING ENGINEERS, INC. "Land Planning, Survey, and Design Specialists" Ms. Moira C. Bradshaw Associate Planner City of Tukwila Planning Department 6200 Southcenter Boulevard Tukwila, WA 98188 Re: June 8, 1987 CITY oF JUN 1997 ilitikiwitaki, Dept Supplemental Soils Report and Investigation for Silver View Lots 1 Through 3 and 20 through 22 (Mitchell Property) Our Job No. 2262 Dear Moira: Please be advised that we have just received the updated report and recom- mendation from GeoEngineers Inc., dated June 1, 1987, for the above - referenced project. As you may recall, the initial study did not include test pits on the Mitchell property, and it was suggested that we provide this updated information to you before final approval. At this time, I am enclosing two copies of the draft supplemental report for your review. This report concludes that soil conditions on this site are identical to soil conditions on the balance of the property and that there are no unusual conditions that would warrant any other considerations other than those already outlined in the original amended report for this project. Therefore, the conditions of the SEPA review and the plat approval should be identical for this portion of the development as for the original site. You will also note that ground water seepage was generally not prevalent on this parcel, and only one of the test pits included evidence of ground water infiltration to any degree. Would you please proceed to review this report and notify this office if you have any questions or comments. Thank you. TAB /sm C249.11 enc: cc: Respectfully, 1 A. Thoma Barghausen, P.E. President (2) Soils Report Mr. Dana B. Mower, Barghausen Consulting Engineers, Inc. 6625.South 190th, #102 • Kent, Washington 98032 • (206) 872 -5522 RECEIVED CITY OF TUICWIIA JUN 9 1987 IMMO REPORT :SUPPLEMENTAL GEOTECHNICAL ENGINEERING SERVICES SILVERVIEW PLAT TUKWILA, WASHINGTON FOR THB COLORADO CORPORATION GeoEngineers Incorporated (206) 746-5200 Fax. (206) 746 -5068 2405 - 140th Ave. N.E. Bellevue, WA 98005 GeoEngineers Incorporated June 1, 1987 THB Colorado Corporation c/o Barghausen Consulting Engineers, Inc. 6625 South 190th, Suite 102 Kent, Washington 98032 Attention: Mr. Tom Barghausen Gentlemen: Report Supplementary Geotechnical Engineering Services Silverview Plat. Tukwila, Washington File No. 1103 -02 -1 Consulting Geotechnicat Engineers and Geologists INTRODUCTION AND SCOPE This report presents the results of our supplementary geotechnical engineering services for a portion of the proposed Silverview development in Tukwila, Washington. The proposed area to be platted has been extended to include the parcel of land lying between the north edge of the original property explored and Slade Way shown in the Site Plan, Figure 1. Authori- zation for our services was provided verbally by Mr. Tom Barghausen of Barghausen Consulting Engineers, Inc. on May 18, 1987. These services are a continuation of our involvement in the project, which included our report dated January 28 and our amended report dated March 30, 1987. The additional property will be divided into six lots for a total of 22 lots in the development. The access road to the development, 53rd Place South, will extend southward from Slade Way. Access from 54th Avenue South has been eliminated. The purposes of our services are to explore subsurface conditions within the parcel under option, compare the results with the information developed during our earlier studies and evaluate whether our previous recommendations are appropriate. THB Colorado Corporation June 1, 1987 Page 2 SITE CONDITIONS SURFACE CONDITIONS The ground surface slopes downward from southwest to northeast at an average inclination of 20 percent. Ground surface elevations vary from Elevation 270 at the southwest corner of the parcel to Elevation 200 near the northeast corner. The site is covered with dense brush and thick stands of deciduous trees. A few small drainage swales extending west to east were observed in the south - central portion of the site. These carried a small amount of water at the time of our field visit. Existing residences are located west and east of the parcel. FIELD EXPLORATIONS Subsurface.conditions within the parcel were explored by excavating six test pits at the locations shown in Figure 1. These test pits are numbered 16 through 21 to continue the sequence begun in our earlier studies. Test pit locations were determined by pacing and taping from existing features. Elevations at the test pits were determined by interpolation from a topo- graphic map prepared by Barghausen Consulting Engineers, Inc. Locations and elevations should be considered accurate only to the degree implied by the methods used. Test pits were excavated using a rubber -tired backhoe provided by Barghausen Engineers. These test pits were continuously logged in the field by an engineering geologist from our firm who identified the various soil strata encountered, obtained representative samples from the test pits, observed ground water seepage conditions, and maintained a detailed log of each test pit. The soils were visually classified in general accordance with the system described in Figure 2. Logs of the test pits are presented in Figures 3 and 4. SUBSURFACE CONDITIONS' In general, subsurface conditions are similar to those identified in the eastern portion of the original property studied. A forest duff layer having an average thickness of 6 inches mantles the site. The forest duff is generally underlain by a loose and soft silty sand unit which contains . GeoEngineers Incorporated THB Colorado Corporation June 1, 1987 Page 3 roots and organic matter; the unit ranges in thickness from 1 to 3 feet. Loose to medium dense silty sand interlayered with sandy silt underlies this unit. Very stiff to hard glacially consolidated silt was encountered at depths ranging from 1 to 8 feet in the test pits. Ground water seepage was observed in Test Pit 21 at a depth of 4 feet. This seepage represents water perched on top of the glacially consolidated soils. We expect that such seepage will be prevalent within the site during the, late winter and early spring months. CONCLUSIONS AND RECOMMENDATIONS Based on the results of the additional explorations previous test pits, we conclude that the site may accordance with the recommendations provided in our March 30, 1987. A large landslide Slade Way. Information have extended onto the regrading during reconstruction of Slade Way obliterated evidence of any movements in that area. Our examination of the property during these explorations did not reveal evidence of recent instability. There is a potential for shallow surficial creep at the site. This can be controlled by appropriate site grading and drainage improvements. our and comparison with be developed in report dated. amended occurred in 1960 -61 on property to the north across in our files indicates that those past movements may extreme northwest corner of this parcel. However, 0 0 o - GeoEngineers Incorporated THB Colorado Corporation June 1, 1987 Page 4 We trust that this information meets your present. needs. If you have any questions concerning this report or if we can provide additional information, please contact us. +o�' 9�1 Gd 01ASHr�y \\�� o Yours very truly, GeoEngineers, Inc. ,e4/..1 aa.4.- Herbert R. Pschunder P „ect Engineer c' K. Tuttle rincipal HRP:JKT:wd Attachments Three copies submitted Copyright © 1987 GeoEngineers, Inc., All Rights Reserved GeoEngineers Incorporated Slade Way Property Line 50 100 SCALE: 1" = 50' 2 19 REFERENCE: DRAWING ENTITLED "PRELIMINARY PLAT OF SILVE.RVIEW ", BY BARGHAUSEN CONSULTING ENGINEERS, INC., DATED 5- 11 -87. KEY: 1* TEST PIT NUMBER AND LOCATION FOR SUPPLEMENTAL STUDY TEST PIT NUMBER AND LOCATION FOR PREVIOUS STUDY GeoEngineers moo Incorporated SITE PLAN AMMO FIGURE 1 GEI 85 -85 SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP SYMBOL COARSE GRAINED SOILS MORE THAN 601E RETAINED ON NO. 200 SIEVE GRAVEL MORE THAN 60% Of COARSE FRACTION RETAINED . ON NO. 4 SIEVE CLEAN GRAVEL OW GROUP NAME WELL - GRADED GRAVEL. FINE TO COARSE GRAVEL . GP POORLY - GRADED GRAVEL GRAVEL WITH FINES . GM • SILTY GRAVEL GC CLAYEY GRAVEL SAND MORE THAN 60% Of COARSE FRACTION PASSES NO. 4 SIEVE CLEAN SAND SW WELL - GRADED BANG, FINE TO COARSE BANG 8P POORLY - GRADED SAND SAND WITH FINES 3M SILTY BAND • 8C .CLAYEY BAND FINE GRAINED SOILS MORE THAN 60% PASSES NO. 200 SIEVE SILT AND CLAY LIQUID LIMIT LESS THAN 60 INORGANIC ORGANIC ML SILT . CL OL CLAY ORGANIC SILT, ORGANIC "CLAY SILT AND CLAY LIQUID LIMIT 60 OR MORE INORGANIC ORGANIC MH SILT OF HIGH PLASTICITY, ELASTIC SILT CH OH CLAY OF HIGH PLASTICITY. FAT CLAY ORGANIC CLAY, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: 1. Field classification 1s based on visual examination of soil In general accordance with ASTM D2488 -83. 2. Soil classification using laboratory tests Is based on ASTM D2487 -83. 3. Descriptions of soil density or consistency are based on Interpretation of blowcount data, visual appearance of soils, and /or test data. SOIL MOISTURE MODIFIERS: Dry - Absence of moliture, dusty, dry to the touch Moist - Damp, but no visible water Wet - Visible Ire• water or saturated, usually soli Is obtained from below water table `01 GeoEngineers � Incorporated SOIL CLASSIFICATION SYSTEM FIGURE 2 GEI 68 -85 1103 -02 -1 DEPTH BELOW GROUP SOIL GROUND SURFACE CLASSIFICATION (FEET) SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT 16 APPROXIMATE ELEVATION: 248 FEET 0 - 0.5 FOREST DUFF 0.5 - 2.5 SM DARK BROWN SILTY FINE SAND WITH ORGANIC MATTER AND OCCASIONAL GRAVEL, ROOTS AND WOOD (LOOSE, MOIST) 2.5 - 5.0 SM /ML INTERLAYERED MOTTLED BROWN AND CRAY FINE TO MEDIUM SAND AND LIGHT BROWN SILT (MEDIUM DENSE AND STIFF, MOIST) 5.0 - 9.5 ML GRAYISH BROWN SILT (HARD, MOIST) TEST PIT COMPLETED AT 9.5 FEET ON 5/19/87 NO GROUND WATER SEEPAGE OBSERVED DISTURBED SAMPLES OBTAINED AT ,4.0 AND 7.0 FEET TEST PIT 17 APPROXIMATE ELEVATION: 259 FEET 0 - 0.5 FOREST DUFF 0.5 - 2.0 SM DARK BROWN SILTY FINE SAND WITH ORGANIC MATTER AND OCCASIONAL GRAVEL, ROOTS AND WOOD (LOOSE, MOIST) 2.0 - 5.5 SP -SM BROWN FINE TO MEDIUM SAND WITH SILT AND OCCASIONAL GRAVEL (LOOSE TO MEDIUM DENSE, MOIST) 5.5 - 8.0 SP -SM BROWN FINE SAND WITH SILT (MEDIUM DENSE, MOIST TO WET) 8.0 - 10.0 SM /ML INTERLAYERED BLUE -CRAY SILTY FINE SAND AND SANDY SILT (MEDIUM DENSE AND STIFF, MOIST TO WET) TEST PIT COMPLETED AT 10.0 FEET ON 5/19/87 NO GROUND WATER SEEPAGE. OBSERVED DISTURBED SAMPLE OBTAINED AT 7.0 FEET TEST PIT 18 APPROXIMATE ELEVATION: 238 FEET - 1.0 ML DARK BROWN SANDY SILT WITH ORGANIC MATTER•AND OCCASIONAL GRAVEL AND ROOTS (SOFT, MOIST) ML MOTTLED GRAYISH BROWN SILT WITH SAND (VERY STIFF, MOIST) GRADES TO HARD AT 4.0 FEET TEST PIT COMPLETED AT 10.0 FEET ON 5/19/87 NO GROUND WATER SEEPAGE OBSERVED DISTURBED SAMPLE OBTAINED AT 6.0 FEET 1.0 - 10.0 THE DEPTHS ON THE TEST PIT LOGS, ALTHOUGH SHOWN TO 0.1 FEET, ARE RASED ON AN AVERAGE OF MEASUREMENTS ACROSS THE TEST PIT AND SHOULD BE CONSIDERED ACCURATE TO 0.5 FEET. A GeoEngineers \`0 Incorporated 1 LOG OF TEST PIT FIGURE 3 GEI 68 -85 DEPTH BELOW GROUP SOIL GROUND SURFACE CLASSIFICATION (FEET) SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT 19 APPROXIMATE ELEVATION: 214 FEET 0 - 2.0 ML DARK BROWN SANDY SILT WITH ORGANIC MATTER, OCCASIONAL GRAVEL AND ROOTS (SOFT TO MEDIIJM STIFF, MOIST) 2.0 - 4.0 SP -SM BROWN FINE SAND WITH SILT AND OCCASIONAL GRAVEL (MEDIUM DENSE, MOIST) 4.0 - 10:0 ML GRAYISH BROWN SILT (STIFF TO VERY STIFF, MOIST) GRADES TO HARD AT 6.0 FEET TEST PIT COMPLETED AT 10.0 FEET ON 5/19/87 NO GROUND WATER SEEPAGE OBSERVED DISTURBED SAMPLES OBTAINED AT 1.0 AND 7.0 FEET TEST PIT 20 APPROXIMATE ELEVATION: 210 FEET 0 - 1.0 ML • DARK BROWN SANDY SILT WITH ORGANIC MATTER, OCCASIONAL GRAVEL AND ROOTS (SOFT, MOIST) 1.0 - 3.0 SM /ML INTERLAYERED BROWN SANDY SILT AND SILTY FINE SAND (SOFT TO MEDIUM STIFF AND LOOSE, MOIST) 3.0 - 5.0 SM BROWN SILTY FINE SAND WITH SILT LENSES (MEDIUM . DENSE, MOIST) • 5.0 - 10.0 ML BROWNISH CRAY SILT (STIFF TO VERY STIFF, MOIST) GRADES TO HARD AT 6.0.FEET TEST PIT COMPLETED AT 10.0 FEET ON 5/19/87 NO GROUND WATER SEEPAGE OBSERVED DISTURBED SAMPLES OBTAINED AT 2.0 AND 8.0 FEET TEST PIT 21 APPROXIMATE ELEVATION: 225 FEET 0 - 0.5 FOREST DUFF 0.5 - 1.5 ML DARK BROWN SANDY SILT WITH ORGANIC MATTER AND OCCASIONAL GRAVEL (SOFT, MOIST) 1.5 - 4.0' SP -SM BROWN FINE TO MEDIUM SAND WITH SILT AND OCCASIONAL GRAVEL (LOOSE TO MEDIUM DENSE, MOIST TO.WET) 4.0 - 10.5 ML MOTTLED BROWN AND CRAY SILT AND SANDY SILT WITH OCCASIONAL LAYERS OF SILTY FINE SAND (MEDIUM STIFF TO STIFF, MOIST) GRADES TO VERY STIFF AT 7.0 FEET TEST pIT COMPLETED AT 10.5 FEET ON 5/19/87 MODERATE GROUND WATER SEEPAGE OBSERVED AT 4.0 FEET SLIGHT CAVING FROM 4.0 TO 7.0 FEET DISTURBED SAMPLES OBTAINED AT 1.0 AND 6.0 FEET - slob � GeoEngineers �o Incorporated LOG OF TEST PIT FIGURE 4 A F ID A V I T O F D I S T RI, U T I O N I, _Jc70mrg- jC4Sa--J hereby declare that: [[ Notice of Public Hearing 0 Notice of Public Meeting O Board of Adjustment Agenda Packet [[ Board of Appeals Agenda Packet O Planning Commission Agenda Packet [[ Short Subdivision Agenda Packet [[ Determination of Nonsignificance Mitigated Determination of Non - significance O Determination of Significance and Scoping Notice O Notice of Action O Official Notice [[ Notice of Application for J Other Shoreline Management Permit 0 Shoreline Management Permit J Other was mailed to each of the following addresses on Joel Haggard 2426.Financial Center Seattle,-WA 98161 Tom Barghausen Dana Mower 6625 S. 190th #102. Kent, WA 98032 Karen Beatty Washington State Dept of Ecology Environmental Review Section Mail Stop PV -11 c/o Abbott Raphael Olympia, WA 98504 y /s , 1917. Renton Record Chronicle - Published 5 -17 -87 Name of Project File NumberF"J 3 s7 —e6 • CHECKLIST: ENVIRONMENTAL REVIEW MAILINGS ( ) U.S. Army Corps of Engineers ( ) Federal Highway Administration FEDERAL AGENCIES ( )U.S. Environmental Protection Agency ( )U.S. Department of H.U.D. (Region X) WASHINGTON STATE AGENCIES ( ) Office of Archaeology ( ) Transportation Department ( ) Department of Fisheries ( ) Office of the Governor ( ) Planning & Community Affairs Agency ( 1-pg. of Social and Health Services . of Ecology, Shorelands Division ept. of Ecology, SEPA Division * )Department of Game )Office of Attorney General * Send checklist with all determinations KING COUNTY AGENCIES ) Dept. of Planning & Community Devel ) Fire District 18 ) Boundary Review Board ) Health Department ( ) South Central School District ( ) Tukwila Library ( ) Renton Library ( ) Kent Library ( ) Pacific Northwest Bell Telephone ( ) Seattle City Light ( ) Washington Natural Gas ( ) Water District 75 ( ) Seattle Water Department ( ) Group W Cable ( ) Kent Planning Department ( ) Tukwila Board of Adjustment ( ) Tukwila Mayor Tukwila City Departments: ( ) - Public Works ( ) - Parks and Recreation ( ) - Police ( ) - Fire ( ) - Finance ( ) - Planning /Building • ( )Fire District 1 ( )Fire District 24 ( )Building & Land Development Division - SEPA Information Center SCHOOLS /LIBRARIES ( )Highline School District ( )King County Public Library ( )Seattle Municipal Reference Library UTILITIES ( )Puget Sound Power & Light ( )Val -Vue Sewer District ( )Water District 20 ( )Water District 25 ( )Water District 125 ( )Union Pacific Railroad CITY AGENCIES ( )Renton Planning Department ( )Tukwila Planning Commission Tukwila City Council Members: ( )- Edgar Bauch ( )- Marilyn Stoknes ( )- Joe Duffie ( )- Mabel Harris ( )- Charlie Simpson ( )- Jim McKenna ( )- Wendy Morgan OTHER LOCAL AGENCIES ) Puget Sound Council of Government(PSCOG) ( )METRO Environmental Planning Division ) Puget Sound Air Pollution Control Agency Office /Industrial 10,000 gsf or more )Tukwila /Sea -Tac Chamber of Commerce Residential 50 units or more Retail 100,000 gsf or more MEDIA ) Daily Journal of Commerce ( )Highline Times Renton Record Chronicle Tyr A ( )Seattle Times .t1 If to 6e eGarLtvi & 5-11- g City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 (208) 433 -1 Boo Gary L. VanDusen, Mayor LETTER OF T R A N S M I T T A L TO KAREN BEATTY DATE 5 -15 -87 Washington State Dept. of Ecology REGARDING Silverview Subdivision Environmental Review Section Mail Stop PV -11 c/o Abbott Raphael Mitigated Dec. of Nonsignificance EPIC - 354 -86 WE ARE SENDING YOU THE FOLLOWING Attached [ Under separate cover COPIES DESCRIPTION Mitigated Der_ of Nnnsignificance THESE ARE TRANSMITTED EIFor approval For review and comment Fnvirnnmental Checklist El For your use and information Soils Report As requested EOther Cnnditinns Ma COMMENTS Should you have any questions nr desire any further information, please call me_ (206) 433 -1849. SIGNED Joanne Johnsofi (LOT /50) Planning Department • • EPIC: 354 -86 Silverview Plat MITIGATING MEASUR, Storm Drainage MP ( ..1 1987 1L A PLANNING DEPT. 1. The applicant shall limit discharge to "ti Wasfiington State Department of Transportation drainage system in accordance with WASHDOT and City of Tukwila requirements. Written approval from WASHDOT shall be required prior to issuance of any utility permits. 2. Recommendations of the soils report regarding storm drainage from individual building sites shall be followed. 3. A representative of GeoEngineers shall determine necessity of permanent subsurface drainage around cut areas during monitoring phase, and shall include conclusions in final inspection report to the City. Soils 4. Additional test pits and recommendations shall be conducted by the soils engineer in proposed 53rd Place South adjacent to Lots 1, 2, 3, 20, 21 and 22. 5. 7'11 111' "A geotechnical engineer's report may be required for individual building permits issued in the plat. At the time of submittal for a building permit on each lot, a letter of opinion shall be submitted from a soils engineer indicating whether or not the proposed construction will require any special foundation construction requirements or procedures, or if any specific on- site testing is required based on the configuration of the house and the orientation within the lots. If the soils engineer determines that the recommendations included within the reports on file in the City of Tukwila for the Silverview project are adequate to address specific building foun- dation requirements for the individual lot, then the letter shall so state and another soils report or field investigation will not be required. If unusual conditions or concerns are identified by the soils engineer, then a supplemental report addressing that specific lot may be required prior to the issuance of a building permit. This condition shall become a note on the plat." above modification to the wording of Condition No. 5 is more .sely relate to the specific recommendations included within t .mended report prepared by .-•Engineers for this project, on page under the paragraph titled "General ". n that paragraph, the en •' eer states that conventional construction procedures '11 be approp '. e for the project in most cases, but some consultation may b- - :sired and, in unusual cases, a specific design may require an addi .nal 1 -stigation. We do not want to require the builder to retai . soils engineer eac time a permit is requested since it is simply u ecessary to do so based on the - tent of the geotechnical work that as already been completed, the recommen• ions of the soils repo s already available, and the specific conclusions su •rized in the , "4 � ` 6. All site work shall be limited to June through October construction and Ni) shall follow the recommendations of the soils report: a) temporary ditches �`�� shall be installed to remove ponded water, and b) french drains will be installed to collect near - surface seepage in necessary areas as determined by soils engineer reviewing field conditions during construction. oils reports. 7. Preparation and construction of buildings, driveways and roads shall follow recommendations of soils report: a) vegetation forest duff, existing fill and disturbed silty soils shall be removed from above areas (approximately 12 -18 inches depending on wetness of soils); b) all areas shall be ade- �/� quately proof rolled; c) structural fill, composition, compaction, and / placement shall comply with recommendations of soils reports; d) on -site PS soils shall only be used for structural fill when moisture content can be vet icor controlled to obtain 95 percent compaction; and e) roadway section shall be constructed per Tukwila Public Works standards. Slopes 8. Rockeries shall not exceed four feet in height. Structurally designed retaining walls shall be used in till soils where retention will exceed four feet. 9. Rockery installation shall be supervised and signed off by soils engineer. • 4/ ,,P 10. A representative of GeoEngineers shall monitor site preparation and earth- Ph work operation in accordance with their recommendations, and provide City ill' Cods with a report stating that work was done in accordance with the March 30, 1987 soils report. Access 11. The applicant shall construct the curbs /gutters /sidewalk and associated storm drains and utility relocations for Slade Way adjacent to the plat. 12. The applicant shall agree to participate in intersection improvements at Klickitat at 51st Avenue South at time of Valley View Estates construction for percentage of project daily vehicle trips. 13. The applicant shall not protest the formation and shall commit to the construction of future L.I.D. for street improvements, including roadway, utility undergrounding, street lighting, and additional storm drainage improvements, as proportionately benefitting their development for street improvement project defined in. the 1987 T.I.P. as Slade Way. 14. The applicant shall execute a developer's agreement for the construction of curb, gutter and sidewalk along 54th Avenue frontage. 15. A tree removal /detention plan shall be submitted and approved by the Plan- ning Department prior to issuance of any permit. (25 /MB.SILVER) ;'11 1.. Depart „ti•at , •i { ? f ' t 4; ?i H1 t._s i° , :(id -i 1 3,.. ;,`'.` (,,,t'$. .° ut w r- m i age t:1 .,t <:t ?::a r -1.quired '1 • t;he: ?rVr" »i :«'.'.€q ty tix -1 �t �.. ..1 .... g• a : / 9:. t {.''rn i n accordance w:.1 ::. f'i 11,. Written. approval +roc:: !. r:'aL r1cf °. of ;;y.s..;,?,,, :1 4R e .:tl r - ...a °{:}m inc.. r.e'pC:r 'di riq • ¶ t {.:4"`331 dr ali .i '::^ E•att a _ 1 rep p a k's 1t at. i tt? s peers psi is Cif #?ritine 44t:?L.C. #a":cl (' y of permanent . 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'. Lt:i:' ",.:'l n; t'..hI.3t 61;:.°;''k 30 1.997 woi- t ::a 1 t, ,., ,i;.'a1� :a.7� ?`spp,>�,:.,:t�.. :•s.itii�. i_":!rl�'..�:.r+"�t._tt;:�: ry °; �•: ; ''t._ 1. ;:7 t .i {. :a a ::,3r" i,i car" • 4 . f'r &i c%n d :r:rrlt r, the p,1t::t . _ Th... ra;: 1i rr na s. �r!.?r c.:�.•ir{ttt.�r^:t.s 4'l Kl.s.r 1 :i� a air;.i t.yiC_., E.s': F e5. i.:t.' . .r i.ti..t: on i Cdr' pt €' `- :t_;r" :lw'?xc # tte .:.ci r::i :fie _..l I r1 o c t c r. t c r Sladt,1 Way C:.(.7.1 ( t. "c: 7 x at-:d 1tw 3 . part :;.t_1.patre in intersection venue South at t.].me of Valley tag ,tage,bf project daily vehicle sh 1 1 riot irc�tc x7t •th wi->` . :.. rt s_:v '.ctior, cat 1. _:i.��rg ,r'r�f ;ci�a�►w9 i_ct :z.lt3rdr' ! . k. t:i r .rl €i r _ \ t €i :v' 1Jprnen; 1'Cat i tS e. 'forma t i tiara end sti;a l . fr.;r st.r° eet ,improve— .t aundirg, ' :::tr...e_E :'t .- 1.,i'...jht- &-'rTr£ :r-res -ii as proportiona '�.. improve ant e ;, .:.. t The i::. if; �.. i;�rijai v ':ii, t ,t.ppr C:2vi" d rti 1 t.� Lit t •e1 c.} er" ' s .etyr lwh C.`.m . nt t4 a 1 • ..:t 1. S..Fr' t 54th T G' :' ..: C.:s 1/ fi:.Enti on 1 a anni r i D p<: tre.11 be, '::emuiomi t.t, ,.a o'-issuance • of • T7,,S n�por �- skulc! 4ec�e f f r y 6t,; id; �,� 0,1 y3/Q.t. w r gt/a`e� ' - cLl i vt spJe c. E I v 'w ii l ( k re6u j neJ n , ,Wr Gl( 0.,cmGre4e r iac,ey t,24.1t- on R!l of v k g C ryhl slabs cAb-1/ gave 6 h. in7aeci-el & -vef i ?Atzd o Pe 0j s %5 el cue e }^ of N cord 2?,s uxe e. wi. 71-4 1L501/5 pt. e5 ^ egu ow- trce.rt f o 1-\1:5 50i Is ret9oY';' Should be ytec_c d on T /oa- loon as .e,r- -mm- vr.eve o.e u i ne rn i s 4` 0-14y fuhtne st-K.01/ 4-16' s�tou l d cuss i ecL crn e lad •09 Q 5 5 00 '2 0,3 '4+ appYDU€c ,'i roc is I) . a Tho4 /C c.ikDd LL►, p 1cii on k d( 4y;6,., r TuCl,Q_- Qne 5-p:teeea. rag umee,,. ►fs ri- cQisckarri soc-I Work ©i 45- ivity52 `y, ilddre.5ses Storm Drainage • • EPIC:354-86 Silverview Plat Mitigating measures 1.The applicant shall limit discharge to the Washington State Department of Transportation drainage system in accordance with WASHDOT and City of Tukwila requirements. Written approval from WASHDOT shall be required prior o issuance of any utility permits. 2. Recommendations of the soils report regardingRtorm drainage from individual building sites shall be 3. A representative of Geoengineers shall determine necessity of permanent subsurface drainage around cut areas during monitoring phase and shall include conclusions in final inspection report to the City. SOILS ��- 4. Additional test pits and recommendations shall be conducted °^ ��~ �� ' by the soils engineer for 53rd Place S. adjacent to lots �� � ~^ 1,2,3,20,21, and 22. 5. A. geotechnical engineers report will be required for each building permit issued in .the plat. The anaLysisyshaLl consist of an individual exploration a+��analysis °p/~76����^�����ion shall ) , be listed as a restriction on the face of the plat. 6. All site work including individual building foundations shall be limited to June through October construction and shall follow the recommendations of the soils re por t : a. ) t emporary ditches es shall be installed to remove pondedwater, b.) french drains will be installed to collect near-surface seepage in neccessary areasscietermined by soils engineer reviewing field conditions duringstruction. 7. tion and construction of buildings, driveways and roadssnall follow recommendations of soils report: a.) vegetgtibn -forest duff, existing fill and disturbed silty soils shall be removed +qgm above areas, (approximately 12 - 18 inches depending on wetness of soil b.) all areas shall be adequately proofrolled, c.) �structural fill , composition, compaction, and placement shall comply with recommendations of soils report, d.) on-site soils shall not be used for structural fill, e.) roadway section shall be cunstucted per Tukwila Public Works standards. SLOPES �� \� ,''w~�^° / de+''0r'~~" R. Rockeries shall noL exceed four feet in height. krReLaiing �alls shall be Lsed in till where retention will cd four feet. ° • • 9. Rockery installation shall be supervised and signed off by soils engineer. 10. A representative of Geoengineers shall monitor site preparation and earthwork operation in accordance with their recommendations and provide City with a report stating that work was done in accordance with the March 30, 1987 soils report. ACCESS 11. The applicant shall construct the curbs/gutters/sidewalk and associated storm drains and utility relocations for Slade Way adjacent to the plat. 12. The applicant shall agree to participate in intersection improvements at Klickitat and 51st Avenue South at time of Valley View Estates construction for percentage of project daily vehicle trips . 13. The applicant shall not protest the formation and shall commit to the construction of future L.I.D. for street improve- ments, including roadway, utility undergrounding, street light- ing, and additional storm drainage improvements, as proportionately benefitting their development for street improvement project defined in the 1987 T.I.P. as Slade Way. 14. The applicant shall execute a developer's agreement for the construction of curb, gutter and sidewalk along 54th Avenue frontage. 15. A tree removal/detention plan shall be submitted and approved by the Planning Department prior to issuance of any • permit. EPIC: 354 -86 Silverview Plat MITIGATING MEASURES Storm Drainage 1. The applicant shall limit discharge to the Washington State Department of Transportation drainage system in accordance with WASHDOT and City of Tukwila requirements. Written approval from WASHDOT shall be required prior to issuance of any utility permits. 2. Recommendations of the soils report regarding storm drainage from individual building sites shall be followed. 3. A representative of GeoEngineers shall determine necessity of permanent subsurface drainage around cut areas during monitoring phase, and shall include conclusions in final inspection report to the City. Soils 4. Additional test pits and recommendations shall be conducted by the soils engineer in proposed 53rd Place South adjacent to Lots 1, 2, 3, 20, 21 and 22. and >w 4oa1c�sug g word e subs 't "A geotechnical engineer's report may be required for individual building permits issued in the plat. At the time of submittal for a building permit on each lot, a letter of opinion shall be submitted from a soils engineer indicating whether or not the proposed construction will require any special foundation construction requirements or procedures, or if any specific on- site testing is required based on the configuration of the house and the orientation within the lots. If the soils engineer determines that the recommendations included within the reports on file in the City of Tukwila for the Silverview project are adequate to address specific building foun- dation requirements for the individual lot, then the letter shall so state and another soils report or field investigation will not be required. If unusual conditions or concerns are identified by the soils engineer, then a supplemental report addressing that specific lot may be required prior to • • the issuance of a building permit. This condition shall become a note on the plat." ¢` neers for n t at p oc�r -es i 1 be ap ropri -� o is`u'ltation may. Y- wired and, require an addition. investigat dr to retain a soils ngi•neer each mp y u�ss 4 to do so based on has already al re ad i 1.a,b,1 t design m the bui it i wok �./"r sol some rd ng of Condiiti_on' No. 5 is more closel- dations 'rncl ude Within th - 'amended e.rrt is prof -ct, on pae four rider the par.gr ragraph /he engi 4er s .a e tha L ' a for" the project in u%'Qsual ca e— do—'not a permit i hex= tent�of con n most es, ajsp want orequire req -steel nc' eo-echnic.1 al ses, cific complefted, t e re.commen•. ions of t,h -h specific conclusions summarized in repos. /e azydra,."6/ f,i/& /ie. a `i 6. All site work shall •e limited to June t ugh October construction'a d shall follow the recommendations of the soils report: a) temporary ditches shall be installed to remove ponded water, and b) french drains will be installed to collect near - surface seepage in necessary areas as determined by soils engineer reviewing field conditions during construction. 7. Preparation and construction of buildings, driveways and roads shall follow recommendations of soils report: a) vegetation forest duff, existing fill and disturbed silty soils shall be removed from above areas (approximately 12 -18 inches depending on wetness of soils); b) all areas shall be ade- quately proof rolled; c) structural fill, composition, compaction, and placement shall comply with recommendations of soils reports; d) on -site soils shall only be use' f+� structural fill when moisture content can be controlled to obtain compaction; and e) roadway section shall be constructed per Tukwila Public Works standards. Slopes 8. Rockeries shall not exceed four feet in height. Structurally designed retaining walls shall be used in till soils where retention will exceed four feet. 9. Rockery installation shall be supervised and signed off by soils engineer. E" b PAP D �� 10. A re rresent-at -i -ve � —o f oEng-i - n ers shall monitor ---git e p r epa r ti on 1 e work operation in accordance with the_recommendations, and provide C ty with a report stating that work was done in accordance with the March 30, 1987 soils report. Access 11. The applicant shall construct the curbs /gutters /sidewalk and associated storm drains and utility relocations for Slade Way adjacent to the plat. 12. The applicant shall agree to participate in intersection improvements at Klickitat at 51st Avenue South at time of Valley View Estates construction for percentage of project daily vehicle trips. 13. The applicant shall not protest the formation and shall commit to the construction of future L.I.D. for street improvements, including roadway, utility undergrounding, street lighting, and additional storm drainage improvements, as proportionately benefitting their development for street improvement project defined in the 1987 T.I.P. as Slade Way. 14. The applicant shall execute a developer's agreement for the construction of curb, gutter and sidewalk along 54th Avenue frontage. 15. A tree removal /detention plan shall be submitted and approved by the Plan- ning Department prior to issuance of any permit. (25 /MB.SILVER) EPIC: 354 -86 Silverview Plat MITIGATING MEASURES Storm Drainage 1. The applicant shall limit discharge to the Washington State Department of Transportation drainage system in accordance with WASHDOT and City of Tukwila requirements. Written approval from WASHDOT shall be required prior to issuance of any utility permits. 2. Recommendations of the soils report regarding storm drainage from individual building sites shall be followed. 3. A representative of GeoEngineers shall determine necessity of permanent subsurface drainage around cut areas during monitoring phase, and shall include conclusions in final inspection report to the City. Soils 4. Additional test pits and recommendations shall be conducted by the soils engineer in proposed 53rd Place South adjacent to Lots 1, 2, 3, 20, 21 and 22. 5. "A geotechnical engineer's report may be required for individual building permits issued in the plat. At the time of submittal for a building permit on each lot, a letter of opinion shall be submitted from a soils engineer indicating whether or not the proposed construction will require any special foundation construction requirements or procedures, or if any specific on- site testing is required based on the configuration of the house and the orientation within the lots. If the soils engineer determines that the recommendations included within the reports on file in the City of Tukwila for the Silverview project are adequate to address specific building foun- dation requirements for the individual lot, then the letter shall so state and another soils report or field investigation will not be required. If unusual conditions or concerns are identified by the soils engineer, then a supplemental report addressing that specific lot may be required prior to the issuance of a building permit. This condition shall become a note on the plat." 6. All roads, utilities and related plat improvements shall be limited to June through October construction unless otherwise approved by the Plan- ning Department, and shall follow the recommendations of the soils report: a) ditches shall be installed to remove ponded water, and b) French drains will be installed to collect near - surface seepage in necessary areas as determined by soils engineer reviewing field conditions during construction. - 7. Preparation and construction of buildings, driveways and roads shall follow recommendations of soils report: a) vegetation forest duff, existing fill and disturbed silty soils shall be removed from above areas (approximately 12 -18 inches depending on wetness of soils); b) all areas shall be ade- quately proof rolled; c) structural fill, composition, compaction, and placement _shall_ _comply_-_wi th recommendations of soils _ reports;_ d) I -si tfe soils_ shall _only be used _for _structural f_il1 -when moi sture--content=can be C- controlled - -to -- obtain suitable compac- t- i- on;_and e) roadway section shall be constructed per Tukwila Public Works standards. • Slopes 8. Rockeries shall not exceed four feet in height. Structurally designed retaining walls shall be used in till soils where retention will exceed four feet. 9. Rockery installation shall be supervised and signed off by soils engineer. 10. A qualified soils engineer shall monitor site preparation and earthwork operation in accordance with the recommendations of the soils report, and provide City with a report stating that work was done in accordance with the March 30, 1987 soils report. Access 11: The applicant shall construct the curbs /gutters /sidewalk and associated storm drains and utility relocations for Slade Way adjacent to the plat. 12. The applicant shall agree to participate in intersection improvements at Klickitat at 51st Avenue South at time of Valley View Estates construction for percentage of project daily vehicle trips. 13. The applicant shall not protest the formation and shall commit to the construction of future L.I.D.•for street improvements, including roadway, utility undergrounding, street lighting, and additional storm drainage improvements, as proportionately benefitting their development for street improvement project defined in the 1987 T.I.P. as Slade Way. 14. The applicant shall execute a developer's agreement for the construction of curb, gutter and sidewalk along 54th Avenue frontage. 15. A tree removal /detention plan shall be submitted and approved by the Plan- ning Department prior to issuance of any permit. (25 /MB.SILVER) --- TR ATL:1\— ty)14-41 k.),) L430e1-8\— ipt gr 477_ 7, c."\ N NOY\ 'NA PcS 0117( Lit,,,sL50 _ cotsl-pf Nyy\Lrn L.r1G Psi\ -Pr-) U11 CA) grk.. :TR a _sk_.\ 8\_ Skt_NLL____12t_ S't-stkD 1,tN. T4-1?-1:41((vainLryaS, V AL La SL-...90 alt.MT ,7sA LT I" ccrs-i_ tay.,AAtLAisi, "k".lawkivt:ppsep.,,,XS ItA4\. rDU t1/4A4 STO.S OF__71i1V •-•tr"1 IS covy\P 1-kpkv,ArrukLy4-,t 1Aa 'twc8 _11w sc.to'-u\A k..A3Kci4v*".)%., w=-1 e-PkNat tAck_mit. Igkz TIO4ut_( 9)14,%ac VIRLA1-1 J' PUXJL Te-iwts kLioN. TS 73Z SPAV--CO eZo-o PcP6-17-. TL\ ISTh Stokit UT LI-AM 3144)fr-11,43 ?1--Pf0V-NT7-- _szcS'?__ TI P41 TD serbA, _cs\ 572z. 1=tps-ce WAC 197 -11 -970 MITIGATED DETERMINATION OF NONSIGNIFICANCE Description of Proposal 22 -lot subdivision known as SILVERVIEW Proponent THB Colorado Corporation Location of Proposal, including street address, if any southwest of Slade way and 54th Avenue Intersection; part of Lot 19 Lot 20,,and.. art of_Lot 22,.Block „2 McMi'cken Heights Division No. 1- (unrecorded) and Lot 2 Tukwila Short Plat 81- 20 -SS, NW 1/4 36 -23 -4. Lead Agency: City of Tukwila File No. EPIC- 354 - 86 The lead agency for this proposal has determined that it does not have a probable significant adverse impact on the environment. An environmental impact statement (EIS) is not required under RCW 43.21C.030(2)(c). This decision was made after review of a completed environmental checklist and other information on file with the lead agency. This information is available to the public on request. Q There is no comment period for this DNS xExc This DNS is issued under 197 -11- 340(2). Comments must be submitted by M 28 19R7 . The lead agency will not act on this proposal for 15 days from the date below. Responsible Official Rick Beeler Position /Title Planning Director Address 6200 Southcenter Boulevard, Tukwj0ligd Date 7 h q c3 Signature 'l �� % Phone 433 -1845 You may appeal this determination to the City Clerk at City Hall, 6200 Southcenter Boulevard, Tukwila, WA 98188 no later than 10 days from the above date by written appeal stating the basis of the appeal for specific factual objections. You may be required to bear some of the expenses for an appeal. Copies of the procedures for SEPA appeals are available with the City Clerk and Planning Department. FM.DNS • GeoEngineers Incorporated (206) 746 -5200 Fax. (206) 746 -5068 2405 - 140th Ave N E Bellevue, WA 98005 May 4, 1987 THB Colorado Corporation c/o Barghausen Consulting Engineers, Inc. 6625 South 190th, Suite 102 Kent, Washington 98032 Attention: Mr. Dana B. Mower Mr. Tom Barghausen Gentlemen: Consulting Geotechnical Engineers and Geologists Letter of Clarification Silver View Estates Plat Tukwila, Washington File No. 1103 -02 -1 rip re,i-mr7FT) MAY 9 19871 C: i i . u: t U PLANT \1;4iG DEPT. This letter addresses questions raised by the City of Tukwila regarding our amended report of geotechnical engineering services for the Silver View Estates Plat dated March 30, 1987. We have discussed these items and our responses with Mr. Tom Barghausen of Barghausen Consulting Engineers, Inc. on May 4, 1987. Our responses are as follows: 1. The issue of requiring separate studies for individual residences can best be resolved by evaluating the specific design require- ments of each structure. We do not expect that additional field explorations will be necessary for each residence within the plat. However, as a minimum, geotechnical engineering consultation considering the specific design requirements of individual residences in releation to site conditions is appropriate. In some instances, additional explorations may be warranted. • • THB Colorado Corporation May 4, 1987 Page 2 2. Residential construction can be done at all seasons of the year. During wet weather, contractors will have to exercise care to protect bearing soils from disturbance. This may involve tempor- ary ditching to collect and divert runoff and placing crushed rock to protect the bearing soils in footing excavations. It will also be necessary to substitute imported clean granular fill for native soils to permit fills to be properly compacted. 3. On -site soils can be used as structural fill provided earthwork is done during periods of prolonged dry weather when the soils can be moisture conditioned to obtain 95 percent compaction. We trust that this letter meets your present needs. Please contact us if you have any questions concerning the information presented herein. HRP:JKT:cs Five copies submitted Yours very truly, GeoE. :_ neers, Inc. Ja Pr uttle ncipal GeoEngineers Incorporated • BARGHAUSEN CONSULTING ENGINEERS, INC. "Land Planning, Survey, and Design Specialists" May 4, 1987 Ms. Moira Carr Bradshaw Associate Planner Planning Department City of Tukwila 6200 Southcenter Boulevard Tukwila, WA 98188 Ni_� t -- MAY 5 1987 Ci"l t-is PLA1dMNG DEPT. Re: Comment on Mitigating Measures for Silver View Project Our Job No. 2262 Dear Moira: I have received your letter, dated April, 29, 1987, together..with a copy of the proposed mitigating measures for the Silver View plat under your File No. 354 -86. We are currently putting together the final preliminary plat exhibits which will include the ten items that you have requested in your April 29 letter. A complete_ grading plan of the project, together with a street cross section and profile, will be forwarded to your office, hopefully, by Monday or Tuesday, May 4 or May 5. If we are delayed for any reason, I will have it delivered to your office while you are out of town so that you can have it for review immediately upon your return on May 11. One of the exhibits that will be provided will include a revised preliminary plat layout which will incorporate modifications of the proposed utility services for the project to take into consideration the comments and concerns of Mr. Phil Fraser of the City of Tukwila Department of Public Works. In particular, both sanitary sewer and storm drainage improvements will be identified, along with proposed driveway access locations for each of the lots. We understand that vertical curb and gutter will be used as opposed to rolled curb, and this will necessitate the selection of driveway locations in advance. At this time, I would like to comment specifically on the mitigating measures that have been proposed for the project. I will address each of the mitigating measures as follows for your review. Basically, all of the mitigating measures are acceptable, subject to clarification and /or modification of several of the conditions as noted. 6625 South 190th, #102 • Kent, Washington 98032 • (206) 872 -5522 Ms. Moira Carr Bradshaw Associate Planner Planning Department City of Tukwila -2- May 4, 1987 SUMMARY OF COMMENTS ON MITIGATING MEASURES STORM DRAINAGE 1. This condition is acceptable. We have already contacted WSDOT, and we have confirmed that we will be able to discharge into their system. At this time, we will be providing storm retention for the project consistent with city requirements. A general concept for the storm drainage control will be illustrated on the preliminary plat. 2. Individual drainage connections for the lots shall be provided as part of the storm drainage system design as suggested in the soils report. Therefore, this condition is acceptable. 3. We will have a soils engineer on site during critical phases of the construction activity to monitor subsurface drainage around any cut areas, and we will have an inspection report submitted to the city in order to satisfy this condition. SOILS 4. We will excavate additional test pits on Lots 1 through 3 and 20 through 22 and provide a supplemental report to your office prior to final approval. This condition will therefore be acceptable. We do not expect that the subsurface soil conditions will be any different on these lots than on the balance of the property. 5. This condition is not acceptable in its present form, and we would suggest that the following wording be substituted. "A geotechnical engineer's report may be required for individual building permits issued in the plat. At the time of submittal for a building permit on each lot, a letter of opinion shall be submitted from a soils engineer indicating whether or not the proposed construction will require any special foundation construction requirements or procedures, or if any specific on -site testing is required based on the configuration of the house and the orientation within the lots. If the soils engineer determines that the recommendations included within the reports on file in the City of Tukwila for the Silver View project are adequate to address specific building foundation requirements for the individual lot, then the letter shall so state and another soils report or field investiga- tion will not be required. If unusual conditions or concerns are identified by the soils engineer, then a supplemental report addressing that specific lot may be required prior to the issuance of a building permite" 'I , c 6 a-1A1,11 cernz Ms. Moira Carr Bradshaw Associate Planner Planning Department City of Tukwila -3- May 4, 1987 The above modification to the wording of Condition No. 5 is more closely related to the specific recommendations included within the amended report prepared by GeoEngineers for this project on page four under the paragraph titled "General." In that paragraph, the engineer states that conventional construction procedures will be appropriate for the project in most cases, but some consultation may be required, and in unusual cases, a specific design may require an additional investigation. We do not want to require the builder to retain a soils engineer each time a permit is requested since it is simply unnecessary to do so based on the extent of the geotechnical work that has already been completed, the recommendations of the soils reports already available, and the specific conclusions summarized in the soils reports. 6. This condition relates to the completion of site work and foundation construction activity on the project relative to adverse weather conditions. We do not have any objection to this condition, provided we can strike the words in the first sentence noted "including individual building foundations." We already anticipate that construction of the project should be accomplished between the months of June and October. Although as a practical matter, the plat construction activity could be undertaken anytime during the year, it would likely be much more costly and time consuming, and the potential for erosion problems occurring during roadway construction in the middle of the winter would be much greater. The whole concept behind our proceeding with the project in the manner that we have to prepare for the initiation of construction in June is to allow us to complete the development improvements and to stabilize all exposed areas in the summertime to minimize the costs and the erosion possibilities. The recommendation to limit foundation construction on the lots between the months of June and October is unnecessary and cannot be accepted. In such a case, the plat will be developed one year and the developer would have to wait until the following year to proceed with any house construction. This is a burden that cannot be incorporated into the project approval as it would be a severe hardship and it is unwarranted based upon the information presented. In reviewing the soils report, it does not state anywhere in the report that the construction of individual house foundations should be limited to the months of June through October. I would draw your attention specifically to the last paragraph on page four of the amended soils report which discusses "site preparation and earthwork" associated with the plat development process. This paragraph talks about the timing limitations and does not include any references to foundation construction. • • Ms. Moira Carr Bradshaw Associate Planner Planning Department City of Tukwila -4- May 4, 1987 On page seven of the report under the section titled "Foundation Support," reference is made to the possibility of moisture problems occurring for the excavation of foundations during wet weather conditions. However, in the last sentence, it clearly states that if the native soils become softened due to excessive moisture, then the founda- tions would need to be developed using a structural fill mat over the existing soils compacted to 95 percent. This is a typical recommendation and would apply to foundation construction anywhere in the Puget Sound region during the winter months. We actually hope to have a number of houses under construction before October of this year, but it is not required that such construction be limited from October through June. The soils engineer has not made this a requirement and has specified what must be accomplished if the individual excavations for lots become softened during construction of each house. It should also be noted that since a consultation letter will be required from the geotechnical engineer on each lot prior to the issuance of a building permit as noted in Condition No. 5, the geotechnical engineer will have an opportunity to take into consideration the time of year when the permit is being applied for and can incorporate special recommenda- tions if necessary. This should provide the protection required by the Building Department to assure that all house foundations will be completed within acceptable standards. 7. This condition is acceptable as it is worded with the exception of Subsection "D." Please refer to the amended geotechnical report prepared by GeoEngineers for this project on page six at the top of the page in the second paragraph. The report specifically states "we recommend that on -site soils not be used as structural fill unless the moisture content can be controlled to obtain 95 percent compaction." This section specifically refers to the use of on -site soils for construction activities and relates the acceptability directly to establish - technical criteria. When the on -site subsurface soils are exposed during construction during the dry summer months, the soils will be suitable for use in fill areas on the project if the moisture content is acceptable. We have been involved in other projects with similar soil conditions, and these types of soils character- istically become "rock hard" during periods of prolonged dry weather and are excellent for base preparation and structural fill if compacted properly. Conversely, if they are saturated above acceptable limits, it is more difficult to use them for structural fill purposes. Since construction activities on the site relative to the plat development are being conducted during the driest months of the year, we obviously want to be able to use these soils for fill purposes provided we can achieve the required moisture content and compaction effort. Ms. Moira Carr Bradshaw Associate Planner Planning Department City of Tukwila -5- May 4, 1987 Since this has specifically been addressed in the soils report, we would ask that this condition be modified to eliminate Subsection "D." SLOPES 8. This condition concerning rockeries is acceptable. 9. This condition concerning rockeries is acceptable. 10. This condition regarding geotechnical supervision is acceptable. ACCESS 11. This condition is acceptable, and provisions will be included in the final plans for these improvements. 12. This condition is acceptable, although we would like to have some information as to the probable extent to which this participation will be required. 13. This condition is acceptable regarding a No Protest Agreement concerning future LID improvements. 14. This condition is acceptable, and the agreement will be executed prior to final plat approval. 15. This condition is also acceptable, and we will want to work out final details of the tree removal plan with your office prior to finalization of the preliminary plat process. We have already located the significant trees on the property and will be submitting a map delineating the trees to be retained sometime during the month of May. I am also attaching with this letter, a supplemental "clarification" letter from GeoEngineers in support of the modified conditions. Quite frankly, after I had an opportunity to review both reports in detail, I found that both reports basically were consistent with how such reports are generally prepared in the industry. It must be remembered that geotechnical engineers typically make recommendations regarding ideal construction practices and conditions, and then include mitigating measures or provisions to be incorporated when such conditions cannot be met. These reports are prepared in the same way. Essentially, the reports confirm that the soils on the site are acceptable for the construction activities contemplated for the project, but that during periods of wet weather, special precautionary measures and construction practices may be required. • • Ms. Moira Carr Bradshaw Associate Planner Planning Department City of Tukwila May 4, 1987 I hope that the modified conditions as we have suggested, combined with the attached letter of clarification, will ,enable you to accept these minor modifications to the SEPA conditions such that we can move forward :with a .final Determination of Nonsignificance. If you have any questions or comments with regard to this information, please let me know. Thank you. TAB /sm C240.74 enc: cc: Thomas A. B hausen, President Letter of Clarification from GeoEngineers Mr. Dana B. Mower, Barghausen Consulting Engineers, Inc. • City of Tukwila PLANNING DEPARTMENT 6200 Southcenter Boulevard Tukwila, Washington 98188 (206) 433 -1849 April 29, 1987 Mr. Thomas A. Barghausen, P.E. Barghausen Consulting Engineers, Inc. 6625 South 190th, #102 Kent, Washington 98032 Dear Tom: Enclosed are the mitigating measures that the City feels are necessary regarding development of Silver View Plat. Several concerns regarding design of the plat: 1. Sewage disposal is with Val Vue Sewer, not City of Tukwila. Accommo- dation for sewer easements west of Lots 9, 8, 7 and 6 is recommended and should be in conformance with Val Vue requirements. Lots 1, 2 and 3 do not appear to have access to a sewer line. Before the City makes a decision on private easements for utilities, right -of -way depths should be verified and documented. 2. Fire hydrants may be no more than 300 linear feet apart. 3. The zoning districts are required to be shown on your plan for the plat as well as surrounding properties. 4. The location and size of the drainage pipe, if existing. 5. Proposed grading plan at 5 -foot intervals. 6. Manner of surface run -off control. 7. Mean lot widths of each lot. 8. PMT of the plat. 9. In checking with the Fire Department, as long as driveway is no longer than 150 feet, a turnaround would not be required. 10. Cross section and profile of streets is requested. • • Mr. Thomas A. Barghausen, P.E. April 29, 1987 Page 2 Please get back to me by May 5th. I will out of town between the 6th and the 11th, and would like to have an environmental recommendation to the responsible official before I leave. If you'd like to meet to discuss any items, please call me at 433 -1848. Si ncerely, &ma.- Moira Carr Bradshaw Associate Planner MCB /sjn City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 (206) 433 -1800 Gary L. VanDusen, Mayor MEMORANDUM TO: Da'q- fe-" / /C FROM: DATE: c.E3 /7/ X9b SUBJECT: ■_/ L u /ie ��' -/b&) /-/////)/ .-7/& z ,‘, • • BARGHAUSEN CONSULTING ENGINEERS, INC. "Land Planning, Survey, and Design Specialists" Ms. Moira Bradshaw City of Tukwila Planning Department 6200 Southcenter Boulevard Tukwila, WA 98188 Re: April 27, 1987 r")-1111THO APR 2'3 1987 Cfl'.Y, OF TUKWILA PLANNING DEPT. Approval of Agreement for Sidewalk Construction for 54th Avenue South Associated with the Silver View Subdivision Our Job No. 2262 Dear Moira: In our last meeting with officials from your department concerning the above - referenced project, it was determined that street improvements to 54th Avenue would not be required based upon the revised plat configuration. As you know, no access is being proposed to 54th Avenue South adjacent to the property and, therefore, we would not be contributing any traffic to this roadway of significance. As a result, improvements are not considered to be necessary. In accordance with the Subdivision Ordinance of the City of Tukwila, the installation of sidewalks are required unless a Sidewalk Agreement is executed. I have reviewed the standard Sidewalk Agreement that was provided to this office, and I want to inform your office that we will agree to sign the Sidewalk Agreement in lieu of constructing the sidewalk. Would you please review this information and incorporate this agreement into the conditions of the preliminary plat analysis for this project. If you have any questions or comments in this regard, please contact me. Thank you. TAB /sm C236.71 cc: Respectfully, Thomas A. Ba g'hausen, P. President Mr. Dana B. Mower, Barghausen Consulting Engineers, Inc. 6625 South 190th, #102 • Kent, Washington 98032 • (206) 872 -5522 7/t -2.w‘ /A'2°°r/071.,eL L-0 • • / MEMORANDUM TO: ROSS EARNST FROM: PHIL FRASER DATE: APRIL 21, 1987 SUBJECT: SILVERSPRINGS PLAT APPROVAL RESPECTIVE OF REQUIRED PUBLIC IMPROVEMENTS For the subject plat approval, recommended is the following: A. The development commit to the construction of curbs/gut- ters/sidewalks and associated storm drains and utility relocations for Slade Way, public right-of-way adjacent to the plat. B. The development commit to the construction of future L.I.D. for street improvements, including roadways, utility e undergroundingi street lighting, additional storm drainage . (::' improvements, as proportionately benefitting their develop- ment for street improvement project defined in the 1987 T.I.P. as Slade Way, in the future, by agreement not to protest the formation of this L.I.D. C. The development commit to the construction of a future L.I.D. for street improvements, including curbs, gutters, {f roadways, storm drainage, utility undergrounding aspropor- tionately benefits their property for the street improve- ment, in the future, by .agreemen not to protest the formation of this L.I.D. `~ ' . g-5. D. Commitment, by agreement to participate in intersection improvements at Klikatat and 51st Ave. South at time of Valleyview Estates..for percentage o daily vehicle le trips � 9tt c°ve hi l e trips gener by Valleyview .- Estates. -- --(-7- \_-' xcx Rick Beeler Moire( Bradshaw Jack Pace AMENDED REPORT GEOTECHNICAL ENGINEERING SERVICES SILVER VIEW ESTATES PLAT TUKWILA, WASHINGTON FOR THB COLORADO CORPORATION b'7 GeoEngineers Incorporated \gip GeoEngineers Incorporated 1206) 746 -5200 2405 - 140th Ave. N.E. Bellevue, WA 98005 March 30, 1987 THB Colorado Corporation c/o Barghausen Consulting Engineers, Inc. 6625 South 190th, Suite 102 Kent, Washington 98032 Attention: Mr. Dana B. Mower Gentlemen: Consulting Geotechnical Engineers and Geologists Amended Report Geotechnical Engineering Services Silver View Estates Plat Tukwila, Washington File No. 1103 -01 INTRODUCTION This report presents the results of our geotechnical engineering services for the Silver View Estates plat in Tukwila, Washington. The project site is located west of 54th Avenue, as shown in the Site Plan, Figure 1.. The scope of our services is described in our proposal dated January 13, 1987. Authorization for our services was provided verbally by Mr. Dana Mower of Barghausen Consulting Engineers, Inc. on January 14, 1987. This amended report supersedes our report dated January 28, 1987. Portions of the report have been revised to more narrowly define the specific recommendations for construction of this project, based on discussions with the City of Tukwila and a subsequent letter by Ms. Moira Bradshaw, Associate Planner, City of Tukwila. ,Responses to certain portions of that letter are presented in the Appendix to this report. The configuration and location of the proposed plat is shown, on the drawing entitled "Preliminary Plat of Silver View Estates ", which you provided us. The property is surrounded on three sides by existing resi- dences and is presently undeveloped. Proposed grades for the access roadways to the plat indicate cuts of up to 7 -1/2 feet. Site grading for THB Colorado Corporation March 30, 1987 Page 2 Individual lots will be dependent on specific house designs. A total of 18 lots are included in the plat. Fifty- fourth Avenue will be widened to the west during development. SCOPE The purpose of our services is to develop general geotechnical design criteria for site development. Separate studies may be appropriate for individual residences, depending upon the specific design requirements of each structure. Specifically, the scope of our services includes: 1. Exploring subsurface soil and ground water conditions by exca- vating a series of test pits with a backhoe provided by Barghausen Engineers. 2. Performing a limited laboratory test program to identify the general suitability for use of on -site soils in earthwork required in plat development. 3. Providing recommendations for earthwork criteria including stripping requirements, temporary and permanent cut and fill slopes, and compaction criteria. 4. Providing general recommendations with respect to the design of foundations for individual family residences. 5. Presenting our findings in a written report. SITE CONDITIONS SURFACE CONDITIONS The ground surface in the extreme western portion of the site is nearly level. The remainder of the site slopes moderately downward toward 54th Avenue. Cut slopes averaging approximately 5 feet in height exist along the west side of 54th Avenue. We observed no indications of deep- seated sliding within the plat. Several leaning deciduous trees in the eastern portion of the site are indicative of shallow soil creep in the forest duff and weathered soil strata to a depth of about 3 feet. GeoEngineers Incorporated THB Colorado Corporation March 30, 1987 Page 3 The site is covered with dense brush and thick stands of deciduous trees. There are a few small groups of evergreen trees. Four small areas of shallow (0.5 to 1.0 feet) standing water were observed in the extreme western portion of the site. These are indicated in Figure 1. FIELD EXPLORATIONS Subsurface conditions within the plat were explored by excavating 15 test pits at the locations shown in Figure 1. Test pit locations were determined by pacing from existing features or sighting to nearby houses. Elevations at the test pits were determined by interpolation from a topo- graphic map prepared by Barghausen Consulting Engineers, Inc. Locations and elevations should be considered accurate only to the degree implied by the methods used. Test pits were excavated using a rubber — tired backhoe. Dozer assistance was required to access several test pit locations due to soft forest duff and surficial soils. These test pits were continuously logged in the field by an engineering geologist from our firm who identified the various soil strata encountered, obtained representative samples from the test pits, observed ground water seepage conditions, and maintained a detailed log of each test pit. The soils were visually classified in general accordance with the system described in Figure 2. Logs of the test pits are presented in Figures 3 through 6. Samples from the test pits were examined in our laboratory to confirm field classifications. Moisture contents were measured on samples from the test pits to evaluate the general workability of the soils in their existing state. Results of these tests are presented in Figure 7. SUBSURFACE CONDITIONS The site is mantled with a layer of forest duff having a thickness ranging from 1/2 to 2 feet. In Test Pits 8 and 13, 3 to 4 feet of silty sand fill was encountered below the ground surface. The fill is loose and wet and includes pieces of wood and rubble.tThese areas of fill appear to be localized and are estimated to be less than 500 cubic yards in volume; GeoEngineers Incorporated wet weather. We recommend' that site grading activities be scheduled_ for the. normally drier summer and early fall seasons (June through -0ctober). The initial phase of site preparation should include. installation of temporary ditches to remove ponded water. French drains may also be needed to collect ' GeoEngineers Incorporated THB Colorado Corporation March 30, 1987 Page 5 i near - surface seepage if some areas. These should be installed on an as- needed basis during /construction. Decisions on where and to what extent such drainage may be needed should be based on field conditions. Building, driveway and access road areas should be cleared of vegeta- tion and stripped of forest duff or disturbed silty soils. We expect that the depth of stripping will generally be about 12 to 18 inches in all but the wettest periods of the year. A greater depth of stripping should be expected during wet periods since it is probable that disturbance of the subgrade soils will be experienced. The stripped material may be reused in planting areas. We recommend that the existing fill in the vicinity of Test Pits 8 and 13 be removed prior to placing any new fill. We recommend that the native soils exposed by stripping within building, driveway and access road areas be proofrolled with a loaded truck or compacted with heavy equipment. The proofrolling should prepare the surface and aid in detecting any soft areas which may require further excavation before fill placement. During wet weather, proofrolling and compaction of native soils will not be feasible and identification of any zones of soft soils which may'have io he removed or repaired should be done by probing. Therefore site work �s'hould generally not be attempted from the late fall through spring eas We recommend that structural fill required on roadways or in building areas consist of clean pit run sand and gravel compacted to at least 95 per- cent of the maximum dry density determined by the ASTM D -1557 test method. The fill should not contain material in excess of 6 inches in size or deleterious materials such as debris, wood or organic matter. Fill material should contain .less than 5 percent fines (material passing No. 200 sieve) by weight relative to the fraction finer than the 3/4 -inch sieve for use during placement in wet weather. Soils with a higher percentage of fines (generally not exceeding 10 to 12 percent) may be allowed for placement during periods of dry weather, providing that the moisture content can be controlled to achieve the required compaction. Structural fill should be GeoEngineers Incorporated THB Colorado Corporation March 30, 1987 Page 6 placed in loose lifts not exceeding 10 inches in thickness. Each lift should be conditioned to the proper moisture content and compacted to the specified density using vibratory equipment. The on -site soils contain a high percentage of fines and are signifi- cantly above the optimum moisture content for compaction. We recommend that on -site soils not be used as structural fill unless the moisture content be controlled to obtain 95 percent compaction' \ - -/ a - SLOPES We recommend that the sides of any temporary excavations other than shallow drainage ditches be sloped no steeper than 1 -1/2:1 (horizontal to vertical). Permanent cut slopes and slopes in structural fill should be made at 2:1 maximum and should _ be = planted or hydroseeded within 72 hours to minimize erosion. Rockeries may be used in place of cut slopes where the cuts are made principally into the till soils. We recommend that rockeries be limited t 4 feet in height. Where greater height is required, stepped rockeries can be installed, providing that the toe of each stage of rockery lies behind (upslope) of a line drawn at 45 degrees above the horizontal through the toe of the lower stage of rockery. If rockeries are installed, graded back - filling and use of sfilter fabric may be necessary to prevent .loss of soil due to seepage. T% 5 5iloudg suiagYVl5oci 94 54-44-,22 o 5;/ 744 45. ilt09/ -F tk.Q y 0G ; f. MONITORING SQ-7144e, A representative from GeoEngineers, Inc. shoul, monitor ite pre- blot s C paration and earthwork operations on a sufficiently frequent basis to observe the progress of the work, perform representative in- place density tests and evaluate if the recommended compaction and other construction criteria are being achieved. ill �Q 24-<-. u d a. GeoEngineers Incorporated THB Colorado Corporation March 30, 1987 Page 7 FOUNDATION SUPPORT V We recommend that spread footings be founded in the medium dense sand or dense to hard glacially consolidated soils or on compacted structural fill placed as recommended above. We recommend a- minimum width of 16 inches for continuous wall footings., Isolated spread footings should be at least finches square. The minimum depth of embedment for all footings should be ;18 inches. ' For foundations designed and constructed as recommended, an allowable bearing pressure of 2000 pounds per square foot may be used. This value applies to the total of dead and long -term live loads exclusive of the weight of the footing and any overlying backfiil. This value may be increased by one -third when considering wind or seismic loads. We estimate that footing settlements will be less than 1/2 inch. We anticipate that the exposed bearing surfaces in excavations will become softened or disturbed if not carefully protected from exposure to moisture and construction activities. Therefore, we recommend hat these Y 0(04 Ae yr Sv�a Tae rtf 40x41- Poo Yi a o excavations be made during periods of dry weather. �/ If the bearing soils 1 u4S T, become softened, the disturbed soils should be excavated and replaced with structural fill compacted to at least 95 percent of the maximum dry density /as determined by ASTM D -1557. ✓ FLOOR SLAB SUPPORT CJj` 0.�� 41. � ? The sand and silt soils will provide satisfactory support for on -grade slabs if they are not disturbed by construction activities. Disturbed areas should be repaired in the same manner as recommended for footing excava- tions. Slabs may also be supported on structural fill placed and compacted to 95 percent of maximum dry density. !We recommend that a base course layer of imported clean granular fill or -clean crushed rock at least 4 inches._- rth-ick be placed to form a capillary break beneath the slab. .A -positive hydraulic connection should be provided on the downhill side of the resi- dences between the base course layer and the footing drain system recom- ;mended in a subsequent- section. ,A vapor barrier_ should also be installed to minimize the potential for migration of moisture through on -grade slabs'. GeoEngineers Incorporated THB Colorado Corporation March 30, 1987 Page 8 .../DRAINAGE We recommend that surface runoff be directed to a storm drainage system. Concentrated runoff should be prevented from flowing down slopes below residences or driveways.' This should be accomplished by providing a system of curbs, gutters and catch basins. Roof, pavement and foundation drains should be connected_to - -a tightline disposal system. Roof and founda- tion drains should not be combined around structures. The footing- drat -n.system should consist of perforated drains installed, rat":the outside base of the _perimeter footings.' These drains should consist of slotted PVC pipe surrounded by 6 inches of pea gravel wrapped in filter fabric and connected by a tightline system sloped to drain to an appropriate disposal point. A permanent subsurface drainage system may also be appropriate around the periphery of cut areas. The extent and location of these drains can best be established during construction with the assistance of GeoEngineers' representative. These drains should be constructed in the same manner as the footing drains. PAVEMENTS Pavement subgrade areas should be prepared as described under SITE PREPARATION. The pavement subgrade soil should be compacted such that the. upper 1 foot of soil attains at least 95 percent of the maximum dry density. Access roads and paved areas should be underlain by at least 6 inches of clean sand and gravel or crushed rock fill. For the expected light vehicular traffic, we recommend an asphalt concrete paving thickness of 2 inches. SLOPE STABILITY Landslides have occurred in the slope north of Slade Way where unfavor- able conditions such as steep slopes and seepage occur. Those movements have not affected this site. We did not identify any significant signs of instability on the project site. The limited area of shallow, surfi_cial creep noted on the eastern part of the site is not considered significant as it can be controlled by site grading and drainage improvements. Nzt •.t' GeoEngineers Incorporated THB Colorado Corporation March 30, 1987 Page 9 Based on our observations, it is our opinion that the overall slope in the immediate vicinity of the site is stable. Construction of residences may result in a temporary increase in erosion until vegetation is reestab- lished. Some localized sloughing may also be encountered in temporary cuts, particularly if seepage zones are encountered. However, the installation of French drains and i.mmedi ate hydroseeding will minimize sloughing and erosion. USE OF THIS REPORT We have prepared this report for use by Barghausen Consulting Engineers, Inc. and the THB Colorado Corporation with principal emphasis on overall site grading, drainage and roadway requirements. While we have presented general guidelines for design of foundations, floor slab support and related drainage for residential structures, actual design of specific structures will be by others. report by. others for design GeoEngineers, shall be at the builder and /or his client. The data and report should be provided to prospective contractors for their bidding or estimating purposes, but our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. When layout, grading plan and roadway design has been As such, use of the information in this without supplemental consultation by c^ a sole risk and liability of the designer, the plat finalized, we should be retained to review the drawings and specifications to see that our recommendations have been interpreted and implemented as intended and to provide recommendations should modifications be appropriate. The scope of our services does not include services related to con- struction safety precautions and our recommendations are not intended to direct the contractor's methods, techniques, sequences or procedures,(except as specifically described in our report for consideration in design. There are possible variations in subsurface conditions between the explorations and also with time. A contingency for unanticipated conditions should be included in the budget and schedule. Sufficient monitoring, StO F GeoEngineers Incorporated THB Colorado Corporation March 30, 1987 Page 10 testing and consultation by our firm should be provided during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anti- cipated, and to evaluate whether or not earthwork and foundation installa- tion activities comply with contract plans and specifications. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in this area at the time the report was prepared. No other conditions, express or implied, should be understood. 0 0 o - The conclusions and recommendations in this report should be applied in their entirety. If there are any questions concerning this report or if we can provide additional services, please call. ,rr ,rr� 1k• T(1T�'- 4P� � `r {, t ," / /T\ 2 HRP:JKT:wd Attachments Three copies submitted cc: City of Tukwila (2) 6200 Southcenter Blvd. Tukwila, WA 98188 Attn: Ms. Moira Bradshaw Yours very truly, GeoEngineers, Inc. He bert R. Pschunder Project Engineer k Tuttle rincipa.l GeoEngineers Incorporated Property line 3 N ti so . h 4 3, n N N N N N N N N N \\\\ , 1 \\ I Ito 114 ti NN N S. 165th'Court (proposed) N REFERENCE: DRAWING ENTITLED "PRELIMINARY PLAT OF SILVER VIEW ESTATES" BY BARGHAUSEN CONSULTING ENGINEERS, INC. DATED 12/30/86. N KEY: *1 TEST, PIT NUMBER AND LOCATION APPROXIMATE AREAS OF SHALLOW STANDING WATER I p 80 160 1 1 SCALE IN FEET GeoEngineers `" Incorporated SITE PLAN FIGURE 1 GEI 85 -85 SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP SYMBOL GROUP NAME COARSE GRAINED SOILS MORE THAN 60% RETAINED ON NO. 200 SIEVE GRAVEL MORE THAN 60% OF COARSE FRACTION RETAINED ON NO. 4 SIEVE CLEAN GRAVEL GW WELL - GRADED GRAVEL. FINE TO COARSE GRAVEL GP POORLY - GRADED GRAVEL GRAVEL WITH FINES GM SILTY GRAVEL GC CLAYEY GRAVEL SAND MORE THAN 60% OF COARSE FRACTION PASSES NO. 4 SIEVE CLEAN SAND sw WELL - GRADED SAND, FINE TO COARSE SAND SP POORLY - GRADED SAND SAND WITH FINES SM SILTY SAND SC CLAYEY SAND FINE GRAINED SOILS MORE THAN 50% PASSES NO. 200 SIEVE SILT AND CLAY LIQUID LIMIT LESS THAN 50 INORGANIC ML SILT CL CLAY ORGANIC OL ORGANIC SILT, ORGANIC CLAY SILT AND CLAY LIOUID LIMIT 50 OR MORE INORGANIC MH SILT OF HIGH PLASTICITY. ELASTIC SILT CH CLAY OF HIGH PLASTICITY. FAT CLAY ORGANIC OH ORGANIC CLAY. ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: 1. Field classification Is based on visual examination of soil in general accordance with ASTM D2488 -83. 2. Soil classification using laboratory tests is based on ASTM D2487 -83. 3. Descriptions of soil density or consistency are based on Interpretation of blowcount data, visual appearance of soils, and /or test data. SOIL MOISTURE MODIFIERS: Dry — Absence of moisture, dusty, dry to the touch Moist — Damp, but no visible water Wet — Visible free water or saturated, usually soil is obtained from below water table 2 GeoEngineers `� Incorporated SOIL CLASSIFICATION SYSTEM FIGURE 2 GEI 68 -85 DEPTH BELOW GROUND SURFACE (FEET) GROUP SOIL CLASSIFICATION SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT 1 APPROXIMATE ELEVATION: 265 FEET 0 - 1.0 FOREST DUFF 1.0 - 2.0 ML MOTTLED BROWN AND GRAY SANDY SILT WITH GRAVEL (SOFT TO MEDIUM STIFF, WET) 2.0 - 6.0 SM BROWNISH GRAY SILTY FINE SAND WITH GRAVEL (MEDIUM DENSE TO DENSE, MOIST)(GLACIAL TILL) TEST PIT COMPLETED AT 6.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED AT 1.0 AND 2.0 FEET DISTURBED SAMPLES OBTAINED AT 1.5 AND 4.0 FEET 0 - 1.0 1.0 - 3.0 3.0 - 7.0 0 - 1.0 1.0 - 3.0 3.0 - 6.0 0 1.0 1.0 - 5.5 5.5 - 8.0 TEST PIT 2 APPROXIMATE ELEVATION: 282 FEET FOREST DUFF MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, WET) GRAY SILTY FINE SAND WITH GRAVEL (MEDIUM DENSE, MOIST) TEST PIT COMPLETED AT 7.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED AT 1.0 AND 3.0 FEET SM SM TEST PIT 3 APPROXIMATE ELEVATION: 290 FEET FOREST DUFF MOTTLED BROWNISH GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, WET) BROWN SILTY FINE SAND WITH OCCASIONAL GRAVEL (MEDIUM DENSE, WET) TEST PIT COMPLETED AT 6.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED FROM SURFACE TO 3.5 FEET DISTURBED SAMPLED OBTAINED AT 4.0 FEET SM SM SM SM TEST PIT 4 APPROXIMATE ELEVATION: 290 FEET FOREST DUFF MOTTLED BROWN AND GRAY SILTY FINE SAND (LOOSE TO MEDIUM DENSE, MOIST TO WET) BROWNISH GRAY SILTY FINE SAND (MEDIUM DENSE, MOIST) TEST PIT COMPLETED AT 8.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED AT 3.0 FEET DISTURBED SAMPLE OBTAINED AT 6.0 FEET THE ELEVATIONS AND DEPTHS ON THE TEST PIT LOGS, ALTHOUGH SHOWN TO 0.1 FEET, ARE BASED ON AN AVERAGE OF MEASUREMENTS ACROSS THE TEST PIT AND SHOULD BE CONSIDERED ACCURATE TO 0.5 FEET. �� GeoEngineers � Incorporated LOG OF TEST PIT FIGURE 3 GEI 68 -85 DEPTH BELOW GROUND SURFACE (FEET) GROUP SOIL CLASSIFICATION SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT 5 APPROXIMATE ELEVATION: 286 FEET 0 - 2.0 FOREST DUFF 2.0 - 5.0 SP -SM BROWN FINE SAND WITH SILT (LOOSE, MOIST TO WET) 5.0 - 7.0 SP BROWN FINE SAND WITH OCCASIONAL GRAVEL (MEDIUM DENSE, MOIST) TEST PIT COMPLETED AT 7.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED FROM SURFACE TO 3.0 FEET DISTURBED SAMPLES OBTAINED AT 3.0 AND 6.0 FEET 0 - 0.5 0.5 - 2.0 2.0 - 4.0 TEST PIT 6 APPROXIMATE ELEVATION: 283 FEET FOREST DUFF MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST) GRAYISH BROWN SILTY FINE SAND WITH GRAVEL (MEDIUM DENSE , MOIST) TEST PIT COMPLETED AT 4.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED DISTURBED SAMPLE OBTAINED AT 3.0 FEET SM SM TEST PIT 7 APPROXIMATE ELEVATION: 272 FEET 0 - 2.0 FOREST DUFF 2.0 - 4.0 SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH OCCASIONAL GRAVEL (LOOSE, MOIST) 4.0 - 6.0 SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH OCCASIONAL GRAVEL (MEDIUM DENSE, MOIST) TEST PIT COMPLETED AT 6.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED 0 - 4.0 4.0 - 5.5 5.5 - 7.0 TEST PIT 8 APPROXIMATE ELEVATION: 260 FEET SM BROWN SILTY FINE SAND WITH ROOTS, ROCKS AND DEBRIS (LOOSE, WET)(FILL) SM MOTTLED LIGHT BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, WET) SM LIGHT BROWN SILTY FINE SAND (MEDIUM DENSE, MOIST) TEST PIT COMPLETED AT 7.0 FEET ON 1/20/87 SLIGHT GROUND WATER SEEPAGE OBSERVED AT 4.0 FEET k� 0,4411' GeoEngineers 101 Incorporated LOG OF TEST PIT FIGURE 4 G E 168 -85 DEPTH BELOW GROUND SURFACE (FEET) 0 - 2.0 2.0 - 3.0 3.0 - 7.0 GROUP SOIL CLASSIFICATION SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT 9 APPROXIMATE ELEVATION: 238 FEET FOREST DUFF SM ML MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, WET) LIGHT BROWN SILT WITH SAND (HARD, MOIST) TEST PIT COMPLETED AT 7.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED FROM SURFACE TO 3.0 FEET DISTURBED SAMPLE OBTAINED AT 6.5 FEET TEST PIT 10 APPROXIMATE ELEVATION: 238 FEET 0 - 1.0 FOREST DUFF 1.0 - 1.5 SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST TO WET) 1.5 - 4.5 ML TAN SILT WITH SAND (HARD, MOIST) TEST PIT COMPLETED AT 4.5 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED 0 - 1.5 1.5 - 4.0 4.0 - 7.0 TEST PIT 11 APPROXIMATE ELEVATION: 234 FEET FOREST DUFF SM SM LIGHT BROWN SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST) BROWNISH GRAY SILTY FINE SAND WITH GRAVEL (DENSE, MOIST) (GLACIAL TILL) TEST PIT COMPLETED AT 7.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED TEST PIT 12 APPROXIMATE ELEVATION: 255 FEET 0 - 1.0 FOREST DUFF 1.0 - 3.0 SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST) 3.0- 6.0 ML TAN SILT WITH SAND (HARD, MOIST) TEST PIT COMPLETED AT 6.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED „ GeoEngineers ;NO Incorporated LOG OF TEST PIT FIGURE 5 GEI 68 -85 DEPTH BELOW GROUND SURFACE (FEET) 0 - 3.0 3.0 - 6.0 GROUP SOIL CLASSIFICATION SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT 13 APPROXIMATE ELEVATION: 220 FEET SM BROWN SILTY FINE SAND WITH ROOTS AND DEBRIS (LOOSE, WET) SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (DENSE, MOIST) (GLACIAL TILL) TEST PIT COMPLETED AT 6.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED TEST PIT 14 APPROXIMATE ELEVATION: 200 FEET 0 - 1.5 FOREST DUFF 1.5 - 3.0 SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST) 3.0 - 5.0 SM GRAYISH BROWN SILTY FINE SAND WITH GRAVEL (DENSE, MOIST) (GLACIAL TILL) TEST PIT COMPLETED AT 5.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED 0 - 1.0 1.0 - 3.0 3.0 - 5.0 TEST PIT 15 APPROXIMATE ELEVATION: 208 FEET FOREST DUFF SM SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST) BROWNISH GRAY SILTY FINE SAND WITH GRAVEL (DENSE, MOIST) (GLACIAL TILL) TEST PIT COMPLETED AT 5.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED � GeoEngineers kg" Incorporated LOG OF TEST PIT FIGURE 6 FIELD MOISTURE CONTENT DATA Sample Depth Moisture Content Soil Type (Percent) Test Pit (Feet) 1 1 3 4 5 5 6 9 1.5 SM 23.1 4.0 SM 19.1 4.0 SP -SM 27.4 6.0 SP -SM 31.5 3.0 SP 19.7 6.0 SP 20.7 3.0 SM 15.6 6.5 ML 25.2 rGeoEngineers r Incorporated 4W FIELD MOISTURE CONTENT DATA FIGURE 7 A P P E N D I X RESPONSES TO CITY OF TUKWILA LETTER DATED FEBRUARY 23, 1987 FROM MS. MOIRA BRADSHAW Our responses to the various items raised in the letter by Ms. Bradshaw are presented below. Each item corresponds to the numbers used in Ms. Bradshaw's letter. 1. We have reviewed the grading plan shown on the Preliminary Plat of Silver View Estates as prepared by Barghausen Consulting Engineers. The grading plan for the streets indicates maximum cuts and fills of about 4 feet. These can be readily accomplished within the framework of recommendations presented in our report. Since this is a single- family residential plat, actual grades, building locations and other site development features will be at the discretion of the various builders and their clients. If the City determines that supplemental geotechnical review or, analysis is appropriate to enable processing individual building permit. ,applications, this should be made a condition of the plat. It is not practical, nor would it be a prudent business decision to attempt to prepare a single geotechnical report for use by each of the potential lot developers. Rather, the report is intended to establish the design parameters for development of the access roadways and to demonstrate the suitability of the property for the planned use. It is our opinion that the geotechnical information developed in support of the plat application should be processed on this basis. 2. The subject of further exploration and design studies for improve- ment of 54th Avenue South between Slade Way and South 166th Street is beyond the scope of services for which the report was prepared. It would not be prudent, in any case, to excavate test pits along a street as narrow as 54th Avenue South. A - 1 GeoEngineers Incorporated The test pits excavated along the eastern boundary of the site revealed competent subgrade at a depth of 3 feet. Since survey data provided us indicates that widening of the roadway to the west is possible, we conclude that suitable support for new pavement can be readily achieved. The question about stability of the embankment on the east side of 54th Avenue South appears to be totally unrelated to this property and, as such, not the responsibility of our client. 3. The standing water noted at the time of our explorations is a temporary condition which can be readily remedied during general site grading. The installation of other drainage, as noted in our report, will further aid in collecting runoff to avoid ponding. 4. The glacial till encountered in the test pits represents a cap over strata of hard silts and clays and dense advance granular outwash soils. We have completed extensive explorations a short distance to the north which, together with other available information (e.g., WSDOT soil borings for I -5), indicates that the site is underlain by compe- tent soils. 5. See report for discussion of existing fill location. The Preliminary Plat drawing shows that up to about 3 feet of fill will be placed along the east side of 53rd Avenue Court. Structural fill which may be required on individual lots cannot be determined at this time. 6./ Conventional construction procedures are appropriate for this /; project, in our opinion. Conventional inspection procedures may not be, however. We have recommended that our firm be involved in con- struction monitoring to determine if work is being accomplished in accordance with the intent of our recommendations. This will be in support of your inspector's role. If other geotechnical consultants are involved on specific building sites, the same arrangement will be 7. See amended text. The remaining unnumbered items are being addressed directly by Mr. Dana Mower of Barghausen Consulting Engineers. A - 2 GeoEngineers Incorporated • BARGHAUSEN CONSULTING ENGINEERS, INC. "Land Planning, Survey, and Design Specialists" March 27, 1987 Ms. Moira Bradshaw City of Tukwila Planning Department 6200 Southcenter Boulevard Tukwila, WA 98188 RE: Silver View Our Job No. 2262 Dear Moira: 7 SAAR 3 0 1987 CITY O E k.Jl:buii_ PLANNI NG DEPT. I am submitting for your review, additional documents as applicable to the above referenced project as requested in your February 23, 1987, letter. As you know, we have completed our boundary and topographic survey for this site and have re- arranged the lot configurations based upon our meeting in mid February. We have also completed a number of additional engineering designs, particularly as related to the road design (with profiles), as well as a preliminary grading, storm drainage and utilities plan for the site. The plans have been prepared in substantial detail, and please keep in mind that the home sizes and locations are simply suggestions at this point. The final home size, as well as the position on each lot, will be deter- mined by the building contractor at the time the individual building permits are sub- mitted. However, the location of each house is intended to clearly indicate that a reasonable size home (between 2,000 and 3,000 square feet) can be constructed on the lot. I would like to summarize the additional information which we are forwarding as per your February 23, 1987, . letter: 1. GeoEngineers has revised their soils report as applicable to the prelimi- nary plat application and will be forwarding their copy to you prior to March 31, 1987. We have also prepared a grading plan for the project as noted above, and I am enclosing four copies of the preliminary .plat /pre- .. liminary grading plan /preliminary utilities /preliminary storm, drainage plan for your review. The plan indicates the specific elevations of each structure and the access grades into each lot. Based on our design, it is 6625 South 190th, #102 • Kent, Washington 98032 • (206) 872 -5522 Ms. Moira Bradshaw City of Tukwila -2- March 27, 1987 clear that the buildings can be constructed utilizing engineering techni- ques as outlined in the soils report. We do not anticipate any special construction techniques to be utilized during the construction of the homes. Essentially, this site is ideally suited, particularly the eastern half, for the construction of daylight basement homes. The upper portion to the west is ideally suited for either daylight basement or single -story homes. With regard to the city's concern as pertaining to enforcement of the recommendations in the soils report, we would propose to include the soils report recommendations and requirements in the CC &Rs for the project. We would also recommend that the city require the soils report recommendations be followed as per each permit which is issued for the home construction. Beyond this, however, we believe that it is the city's responsibility to enforce any additional restrictions which would be imposed on the project through the normal preliminary plat process. The engineering plans and specifications as submitted indicate a sub- stantial level of detail which we would not normally expect for a preliminary plat, particularly for a preliminary plat application of this size. Essentially, the plans indicate a final design for this project, and there is absolutely no question in our mind that the project is viable and can be constructed on the property as indicated on the plans. If the city feels that additional controls are required, we would suggest that these considerations be addressed in the conditions approving the preliminary plat. We feel that it is strictly the city's responsibility to enforce additional requirements, and we are at somewhat of a loss to recommend further measures which may otherwise guarantee that the city's concerns are satisfied during the construction of the plat, as well as the homes. Again, however, there is no question in our minds that the project can be constructed as per the enclosed plans and that the construction process would be accomplished by utilizing common construction practices. If further technical information is required, then the next step would be to prepare the actual final construction documents for this project. As you are aware, this property was previously granted a preliminary plat based upon various technical data which was submitted a few years ago. Based on our engineering design, it is apparent that the project is still viable at this time. 2. The scope of work as related to the improvements to South 54th Street have been further addressed, in the addendum soils report which you will be receiving shortly. Our only comment with regard to the current concerns relative to slope stability on the eastern half of the right -of -way, is that, typically, properties are only required to provide Ms. Moira Bradshaw City of Tukwila follows: • • -3- March 27, 1987 improvements on the half street fronting their property. The remainder of the right -of -way and roadway lies within the ownership and jurisdic- tion of the City of Tukwila. If further slope problems exist in this area, we believe it is the responsibility of the city to provide measures necessary for slope stabilization. Clearly, because a substantial amount of work has already been completed in this area by the state, and perhaps the city, over a number of years, it is apparent that a substantial amount of thought has been given to the stability of this area. Also, because the road improvements will be constructed entirely within our half of the existing_right -of -way, no work is proposed at this time along the eastern half of the right -of -way. 3. Addressed in the addendum soils report. 4. Addressed in the addendum soils report. 5. Addressed in the addendum soils report. 6. Addressed in the addendum soils report. 7. Addressed in the addendum soils report. The additional documents further requested in your letter are submitted as I. The Washington State Department of Transportation will forward a letter by March 31, 1987, indicating that they have approved the storm drainage discharge from this site into 54th Avenue South which is tributary to the tightline storm drainage system within the I -5 right -of -way. 2. We have included three cross sections of the site, including 54th Avenue South, as well as an additional cross section of the cut slope area at approximately station 1 + 00 along South 164th Place. 3. We are also forwarding copies of the road profile for South 164th Place. You will note that the profile indicates a maximum grade of 15 percent, which is within the design requirements as set forth by the city. As an assurance that the road will be constructed no steeper than 15 percent, our survey department will be completing the final staking on the project. Therefore, the city is virtually guaranteed that the road grades will be no steeper than 15 percent. 4. A revised preliminary plat map which indicates the grading, storm drainage, water and sanitary sewer designs for this project. Ms. Moira Bradshaw City of Tukwila -4- March 27, 1987 I trust that this information will be sufficient to allow you to continue to process the preliminary plat application. We understand that the next step in the review process will be an environmental determination based on the enclosed information. Again, the project can be constructed through the use of normal construction practices, and, therefore, we would request that a Declaration of Non - significance be issued for this project. If you should have any further questions with regard to this information, please feel free to call. Otherwise, I will phone you on March 31, 1987. Mr. Tom Barghausen (872 -5522) will be available should you need additional information before that time. Thank you. Respectfully, Dana B. Mower, P.E. Vice President DBM /tt C227.44 enc: As Noted Above cc: Mr. Rick Beeler, Planning Director, City of Tukwila Mr. Phil Frasier Mr. Ross Earnst T Washington State Department of Transportation District 1 Office of District Administrator 6431 Corson Avenue South #C -81410 Seattle, Washington 98108 206 764.4141 March 26, 1987 City of Tukwila Department of Public Works 6200 Southcenter Boulevard Tukwila, Washington 98188 Dear Mr. Frasier: Duane Berentson Secretary of Transportation RECEIVED MAR 3 0 1987 � 'A C� WORKS P I S Silver Crest Development S. 160th Street and 54th Avenue S. Vicinity 15, MP 153.9 The Washington State Department of Transportation has no objection to the proposed Silver Crest development continuing to discharge to the State drainage system after development. Detention requirements are still under discussion. They will reflect City of Tukwila concerns as well as conveyance limitations of the Washington State Department of Transportation drainage system. Sincerely, RICHARD F. JOHNSON, P.E. - EhVironmentaf and' Special - Services Engineer cc: File (15MP154) Dana Mower, Barghausen Engineers \ CLUD (w ern cr61,orN-°—' ihr„eW/Wr qt,1 OU (0 BARGHAUSEN CONSULTING ENGINEERS, NC. "Land Planning, Survey, and Design Specialists" Mr. Bob Winters Washington State Department of Transportation Highway District No. 1 9611 S.E. 36th Street Mercer Island, WA 98040 RE: Silver View Estates Our Job No. 2262 Dear Bob: March 26, 1987 17,7c v MAR 3 0 1987 TUI WI LA PUBLIC WORKS CEO ‘%),% c4---)ec j>\ In accordance with our last conversation concerning the above - referenced property, I would like to submit for your consideration a storm drainage study for the parcel and the entire basin in which the parcel is located. I am also enclosing copies of our previous correspondence to the. City outlining the downstream storm drainage analysis as per your most recent as-built records. Based on our calculations; it-woltlt1 appear as though the existing ftns . eam storm drainage -bass wo1�"" u d capable of conveying the storm drainage water from no n1 our developed site, but from the entire developed basin as well in an undetained manner. Further, we feel that because the site is located relatively close to the - 405 discharge •oint into Gee ' i �_. • etain storm - water on t is property in order to allow the peak storm flow from this basin to reach the Green River ahead of the peak for the entire basin. You will note that our calculations indicate that under the existing conditions the maximum 10 -year discharge into the existing system would be approximately 4.76 CFS. The discharge of the overall undeveloped basin with the developed project would discharge approximately 5.5 to CFS for the 10 year event. The overall fully developed basin would generate approximately 8.1 CFS as per maximum development allowed under the currently zoning (approximately 3.0 dwelling units per acre, as the zoning in this area is for plats). You will note that the contributing flow from our site would be ap- proximately 1 to 1-1/2 CFS for the 10 year event relative to the existing basin conditions. 6625 South 190th, #102 • Kent, Washington 98032 • (206) 872 -5522 'J 44,f) tv Z 1%� Mr. Bob Winters Washington State Department of Transportation Highway District No. 1 -2- March 26, 1987 Again, we would like to, if at all possible, free discharge into the existing system (we would tightline the system from our plat to the collection point at Slade Way and 54th Avenue South) and our field inspections indicate that the current 24 -inch line located at the intersection of Slade Way and 54th Avenue South is the correction point for the basin. This catch basin in downstream system appears to be operating in an unrestricted manner. Furthermore, because the pipes appear to have been constructed with substantial slopes, the system also appears to be self cleaning. If at, all possible, we would tike to request a letter from you with regard to your conclusions concerning our analysis and, as a minimum, an authorization to discharge from our site into the state system. Please also indicate whether or not detention would be required. Our current deadline for submitting your approval for the preliminary plat (as related to storm discharge) is Tuesday, March 31, 1987. If there is any other information which I can forward to you to assist you in you review, please do not hesitate to call. Respectfully, Dana B. Mower, P.E. Vice President DBM /bb c229.45 enc: As Noted cc: Mr. Phil Frazier, City of Tukwila Ms. Moira C. Bradshaw, City of Tukwila BARGHAUSEN CONSULTING ENGINEERS, INC. "Land Planning, Survey, and Design Specialists" March 24, 1987 Ms. Moira Bradshaw City of Tukwila Planning Department 6200 Southcenter Boulevard Tukwila, WA 98188 RE: Silverview Plat Our Job No. 2262 Dear Moira: RECEIVED CITY OF TUKWILA MAR 2 3 1987 .BUILDING °En. I am enclosing six copies of our revised preliminary plat for ,.the above referenced project for your review. You will note that we have modified the road alignment as well as the lot configuration on this site, and the net result is that we now have 17 lots rather than the 18 as originally proposed. I will be forwarding additional copies of our engineering designs for the plat which will include a road and storm drainage plan along with road profiles for your review. The road plan will include proposed grades on the property and will indicate the specific access grades into each lot and will also delineate areas of cuts and fills along with the location of slope banks and proposed rockeries. You will note that the enclosed plan reflects the revised design as per these parameters. Please continue to process ' this application, and I will anticipate speaking with you tomorrow with regard to the project timing and preliminary plat hearing date. However, please feel free to call if you have any questions before that time. DBM /tt C227.31 enc: Six Copies of Preliminary Plat Respectfully, Dana B. Mower, P.E. Vice President 6625 South 190th, *102 • Kent, Washington 98032 • (206) 872 -5522 City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 (206) 433 -1800 Gary L. VanDusen, Mayor March 11, 1987 Mr. Dana Mower Barghausen Consulting Engineers, Inc. 6625 South 190th, #102 Kent, Washington 98032 Dear Dana: I have not heard from you since our last meeting when we discussed the needs of your project. The March Planning Commission deadline has passed and we have not been able to make a SEPA determination, there - fore we will plan for the April meeting for the proposal. If you have any questions or concerns or wish to go over your interim findings, then please call me at 433 -1848. Sincerely, Moira Carr Bradshaw Associate Planner MCB/ s j n • • City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 (206) 433 -1800 Gary L. VanDusen, Mayor February 23, 1987 Mr. Dana Mower Barghausen Consulting Engineers, Inc. 6625 South 190th, #102 Kent, WA 98032 Dear Dana: Subject: Silver View EPIC 354 -86; 86 -67 -SUB In follow -up to our meeting with Burt Pscunder, I'd like to summarize the con- cerns and further analysis that is required. In general, due to the sensitive nature of the site, the scope of the soils report should be expanded and more definitive. There is a concern that the specific recommendations of the soils engineer will be difficult to enforce during the development of the individual homes. To supplement the expanded soils report the developer should propose how the recommendations of the soils engineer are to be implemented. 1. The soils engineer should have a preliminary grading plan with proposed building elevations to work from. If the buildings require individual engineering analysis, how and under what circumstances will this analysis be provided to prospective builders? This is not normally required for single - family homes. What should, be the scope of further review? 2. The scope of the report needs to be expanded to include the improvement of 54th Avenue South from South 166th Street to Slade Way. - Additional test pits in 54th right -of -way is needed. - Location of proposed roadway pad relative to right -of -way. - Investigation of sliding area located at intersection of 54th and 53rd Place South. - Are bin walls required? - Elaborate in Report Section on public roadways, including recommenda- tion of 24 -hour restriction on preparation and design. 3. Shallow standing water on site would appear to be unacceptable. What pro- posed grading or design recommendations are needed to eliminate the current surface conditions of standing water (p.2). Mr. Dana Mower February 23, 1987 Page 2 • • 4. The dense glacial soils which comprise the subsurface conditions of the site is not clear (p.3). Explicitly cite why subsurface conditions do not need further exploration. Where they are located and at what depths. 5. Where are the limits of existing fill on the site and where will structural fill be required. 6. The report states that appropriate attention must be paid to the details of earthwork, drainage and foundation support, yet goes on to say that conven- tional construction procedures are appropriate in dealing with these issues. The recommendations in the report are needed and will be used by the City to inspect the contractor's method, sequence and procedures which is contrary to the section in the report - Use of This Report. 7. Proofrolling of the roads driveways and buildings is recommended, which cannot (p.5) be accomplished during wet weather. How will a prolonged period of dry weather be defined? Due to the erosion potential and the recommended maximum slope of 2:1 (p.5) the cross sections and proposed grades are essential for review. Preliminary esti- mates of cuts indicate 7 to 10 feet. The soils engineer should provide review of the sections and grading plan. Regarding storm drainage, a letter from WSDOT confirming approval of your use of their system, an indication of whether adequate service exists for the entire drain basin, and a description of the drain basin to be served by their system is required. Regarding streets, show the location of existing 54th Avenue on the site plan. Three cross sections from toe of the existing roadway slope in WSDOT right -of- way, including 54th Avenue improvement - through proposed intersection of 54th - 53rd Place South. - through center of Plat down South 165th Place. - through 53rd Place South cul -de -sac is required. In addition, proposed profiles of rights -of -way 54th - 30' roadway 1' C &G 5' sidewalk and the interior roads is required. The information which needs to be provided is significant. The City will need this information by the 3rd of March in order to allow sufficient review time for a SEPA determination and Planning Commission meetings. If you or Mr. Pscunder have any questions or need clarification, please call me at 433 -1848. Sincerely, Moira Carr Bradshaw Associate Planner MCB/ s j n ti ,/4 Pin 10-/ solL,4 rtouivi- . J',,..) LvLr"l�/7MJ �a'C i'J( I\ la" � )S14-4;1°: �l- /y7� /,J `- I .14: r 7� s L -1 `V �V 1 ^� �� �� zo - W rI MDT L JrS Sot L.L 1 N V eT I U-AT1. .) C s 1--10 tip. 11 - SP Lc-1 ikL STv,t cc(U' X I L U 11\ to LA 1 "S X U tevyi ?kePbsL) ►P\oF!L S" n ISOS+, S S3L2 4SITt S.Ls 07- rattat.av 1 4..--71.0..v W-"z 1164.k.-'% Cl.-: F MI uT-/ 07 Vil LI T y - RA1 w v... \ Lk-11Th \&�... wst T cvt f- arr• torsuI n)Ta '-LS my" 3 Lo n !t 'IN4\1 Lr\ t4, UT-4‘S_ 1--r) 14--)PklS , LA a Kt covsQ Lc se Ls 7-24) lob` 15p1, CaMAO, U UL P L4 N9 p �N p �,+ �'u3U c, k -e4.0 �n-1 5 rrt PkAMm `S' 1,4 vorn 122: f.ts-91,1)vcs-s. 1,1 \ -L)l i k-;-r3 Y.- Lf 1/-Ow -4 I C /Ct7 S'Y tL.LJ 1l, ( • BARGHAUSEN CONSULTING ENGINEERS, INC. "Land Planning, Survey, and Design Specialists" February 3, 1987 Ms. Moira Bradshaw City of Tukwila Planning Department 6200 Southcenter Boulevard Tukwila, WA 98188 FEB GE$MIER 04 1167 CITY Of Ttl WILA PLANNING DEPT. RE: Silver View Ridge Located at 54th Avenue and Slade Way, Tukwila, WA Our Job No. 2262 Dear Moira: As discussed during our telephone conversation this afternoon pertaining to the above referenced, project, I am forwarding the following items for your use in reviewing the preliminary plat. • 1. Two (2) copies of the geotechnical engineering report as prepared by Geo Engineers, Inc. You will . note that Geo Engineers has completed substantial work in this area, particularly relative to the apartment site located approximately a quarter of a mile to the north of our project and adjacent to Slade Way. The results of the study indicate that the site is stable and that ground water conditions and soil characteristics are such that the site will best be worked during the dry weather months. Because we anticipate constructing this project during the spring and summer months, we do not forsee any substantial difficulties relative to meeting the recommendations as set forth in the report. You will also note that the report includes borings in and around the 54th Avenue right -of -way and, based on the test results, the soils engineer anticipates a relatively straight forward road construction process and widening for 54th Avenue. 2. I am also enclosing one (1) copy of our storm drainage analysis of the downstream drainage basin for this project. Attached to our report, I am including one (1) copy of the as -built storm drainage system which will convey water from the site through the DOT enclosed storm drainage system which ultimately discharges into the .Green River a few miles away 6625 South 190th, #102 • Kent, Washington 98032 • (206) 872 -5522 • • Ms. Moira Bradshaw City of Tukwila Planning Department -2- February 3, 1987 We have already forwarded copies of the water availability for this site, however, although we have contacted Puget Power relative to power service for this project, we have not yet received the formal availability letter from them. However, based on our telephone conversations, domestic electrical service is available within approximately 150 feet of the project and some off -site extension of the primary cable will be required. Puget Power is in the process of calculating the cost related to the extension and will be forwarding a letter to us in the near future. Once we have obtained the letter, we will send a copy to you immediately. With regard to the 4th and 5th requests as per your January 12, 1987, summary letter of our pre - development meeting, we are not, at this time, able to forward the tree survey or the cross sections of 54th Avenue. Unfortunately, this site is located in an area bordering many other areas which have been subdivided over the years. Conse- quently, a substantial amount of extra work has been performed in order to accurately locate the boundary corners for the project. Once we have completed our boundary and topographic service, however, we will ,forward them to you immediately and trust that the absence of these documents at this time will not delay the permit process. Basically, once we complete our su "r ys,- we will perform the cross sections and site layout plans for the street and storm drainage system as quickly as possible. However, due to the sheer amount of work which is required to provide this detail, again, we have not been able to complete this item as of this date. Also, with regard to a tree preservation plan showing the significant trees to be saved on the site, it is difficult for us to determine the precise level of detail which would be required to provide you with an accurate plan at this time. Essentially, we would need to decide upon the building configuration, size and height, as well as the location on each lot. Because the choice of the particular type of units to be con- structed on the property will be completed some time in the future, again, we are not able to provide this level of detail. However, having completed a number of subdivisions within the City of Tukwila, we trust that the absence of the latter two documents will not delay this project unduly. We hope that you will agree that both plans require a substantial amount of effort and expense to complete and a number- of decisions must be made to provide accurate drawings relative to the requested plans. Therefore, we would request that the staff condition the recommendation to the council pending the com- pletion of these studies. Clearly, because the preliminary plat can be modified somewhat, upon completion and the recordation of the final plat (which is generally the normal development process), we would hope that the staff would not require engineering plans at this level of detail at this time to complete the'preliminary plat review process. We understand that you will be holding a staff meeting tomorrow to discuss the information which I am forwarding relative to the information requested in your January 12, 1987, letter. Hopefully, the city will be confident in the professional standards adhered to by our company as evidenced by the previous projects which we have completed together in the past. We are equally as concerned as the city relative to Ms. Moira Bradshaw City of Tukwila Planning Department -3- February 3, 1987 the particular issues, however, since we have completed the storm drainage study and geotechnical report for the project, we are confident that the engineering design items can be accommodated as well. Please do not hesitate to call if you have any questions. Otherwise, I will look forward to speaking with you tomorrow relative to setting the preliminary plat hearing dates. Respectfully, Dana B. Mower, P.E. Vice President DBM /tt C220.03 enc: As Noted GeoEngineers Incorporated 12061 746 -5200 2405 - 140th Ave. N.E. Bellevue, WA 98005 January 28, 1987 THB Colorado Corporation c/o Barghausen Consulting Engineers, Inc.° 6625 South 190th, Suite 102 Kent, Washington 98032 Attention: Mr. Dana B. Mower Gentlemen: Consulting Geotechnical Engineers and Geologists Report Geotechnical Engineeriyng Services Silver View Estates Plat Tukwila, Washington File No. 1103 -01 INTRODUCTION This report presents the results of our geotechnical engineering services for. the Silver View Estates plat in Tukwila, Washington. The project site is located west of 54th Avenue, as shown in the Site Plan, Figure 1. The scope of our services is described in our proposal dated January 13, 1987. Authorization for our services was provided verbally by Mr. Dana Mower of Barghausen Consulting Engineers, Inc. on January 14, 1987. The configuration and location of the proposed plat is shown on the drawing entitled "Preliminary Plat of Silver View Estates ", which you provided us. The property is surrounded on three sides by existing resi- dences and is presently undeveloped. Proposed grades for the access roadways to the plat indicate cuts of up to 7-1/2 feet. Site grading for individual lots will be dependent on specific house designs. A total of 18 lots are included in the plat. Fifty— fourth Avenue will be widened to the west , \O during development. 1J SCOPE The purpose of our services is to develop general geotechnical design criteria for site development. Separate studies may be appropriate for TUB Colorado Corporation January 28, 1987 Page 2 individual residences, depending upon the— s_p_e_c :fi c design requirements of each structure.. Specifically, the scope of our services includes: 1. Exploring subsurface soil and ground water conditions by excavating a series of test pits with a backhoe provided by Barghausen Engineers. 2. Performing a limited laboratory test program to identify the general suitability for use of on -site soils in earthwork required in plat development. 3. Providing recommendations for earthwork criteria including stripping requirements, temporary and permanent cut and fill slopes, and compaction criteria. 4. Providing general • recommendations with respect to the design of9 foundations for individual family residences.1 5. Presenting our findings in a written report. SITE CONDITIONS SURFACE CONDITIONS The ground surface in the extreme western portion of the site is nearly level. The remainder of the site slopes moderately downward toward 54th Avenue. Steep cut slopes several feet in height exist along the west side of 54th Avenue. We observed no indications of deep- seated sliding within the plat. Several leaning deciduous trees in the eastern portion of the site . are indicative of shallow soil creep. The site is covered with dense brush and thick stands of deciduous trees. There are a few small groups of evergreen trees. Several areas of shallow standing water were observed in the extreme western portion of the site. These are indicated in Figure 1. FIELD EXPLORATIONS Subsurface conditions within the plat were explored by excavating 15 test pits at the locations shown in Figure 1. Test pit locations were determined by pacing from existing features or sighting to nearby houses. Elevations at the test pits were determined by interpolation from a topo- 1 TIIB Colorado Corporation January 28, 1987 Page 3 graphic map prepared by Barghausen Consulting Engineers, Inc. Locations and elevations should be considered accurate only to the degree implied by the methods used. Test pits were excavated using a rubber —tired backhoe. Dozer assistance was required to access several test pit locations due to soft forest duff and surficial soils. The test pits were continuously logged in the field by an engineering geologist from our firm who identified the various soil strata encountered, obtained representative samples from the test pits, observed ground water seepage conditions, and maintained a detailed log of each test pit. The soils were visually classified in general accordance with the system described in Figure 2. .Logs of the test pits are presented in Figures 3 through 6. Samples from the test pits were examined in our laboratory to confirm field classifications. Moisture contents were measured on samples from the test pits to evaluate the general workability of the soils in their existing state. Results of these tests are presented in Figure 7. SUBSURFACE CONDITIONS The site is mantled with a layer of forest duff having a thickness ranging from 1/2 to 2 feet. In Test Pits 8j and 131 3 to 4 feet of silty sand fill was encountered below the ground surface. The fill is loose and wet and includes'pieces . of wood and rubble/ In the upper portion of the site, represented by Test Pits 2 through 8, the forest duff and fill overlies a 1 -1/2— to 5— foot —thick unit of loose and wet silty sand. This unit is underlain by medium dense silty sand with variable amounts of gravel (recessional outwash). In the lower portion of the site, the forest duff is generally underlain by a loose and soft silty sand and sandy silt unit which ranges in thickness from 1/2 to 2 -1/2 feet. This unit is generally wet. Dense glacially consolidated soils consisting of silty sand with gravel and sandy silt ei derlie__the.loose surficial--soi-ls.and the fill in Test Pit,...13. These soils were encountered at depths ranging from 1 -1/2 to 4 feet at the /test pit locations. THB Colorado Corporation January 28, 1987 Page 4 Ground water seepage was observed in several of the test pits within a few feet of the surface. This seepage most likely represents water perched on top of the glacially consolidated soils or impervious soil layers within the outwash. We expect that perched water levels will fluctuate seasonally. CONCLUSIONS AND RECOMMENDATIONS GENERAL In our opinion, the site is suitable for construction of residences provided appropriate attention is paid to the details of earthwork drainage) and {foundation support We expect that conventional construction procedures will be appropriate for dealing with these factors. IA geotechnical engi -: neering review of the design of individual residences will be appropriate SITE PREPARATION AND EARTHWORK > tih We recommend that site preparation and earthwork be accomplished during periods of prolonged dry weather as the on-site soils are extremely sensitive to moisture and will become very difficult to work with during wet weather. If these activities must take place during wet weather, we recommend that measures be implemented to minimize disturbance and softening of these soils caused by construction traffic and precipitation. These measures could include appropriately placed drainage ditches, subgrade enhancement with filter fabric, placement of gravel, and crushed rock for„:emporary access roads and sequenced excavation for footings and fill subgrade areas. Building, driveway and.-atcess r o d rea should be cleared of vegetation and stripped of forest duff or disturbed silty soils. We expect that the depth of stripping will generally be about. 12 to 18 inches in all but the wettest periods of the year. A greater depth of stripping may be required during wet periods since it is probable that disturbance of the subgrade soils will be experienced. The stripped material may be reused in planting areas. We recommend that the existing fill in the vicinity of Test Pits 8 and 13 be removed "prior to placing any new fill: We recommend that the native soils exposed by stripping within building, driveway and access road areas be proofrolled with a loaded truck or compacted with heavy equipment. The proofrolling should prepare the /surface and aid THB Colorado Corporation January 28, 1987 Page 5 ' in detecting any soft areas which may require further excavation before fill placement. During wet weather, proofrolling and compaction of native soils will not be feasible and identification of any zones of soft soils which may have to be removed or repaired should be done by probin We recommend that structural ^fill?requir d on roadtys or in building areas consist of clean pit run sand and gravel compacted to at least 95 per- cent of the maximum dry density determined by the ASTM D -1557 test method. The fill should not contain material in excess of 6 inches in size or deleterious materials such as debris, wood or organic matter. Fill material should contain less than 5 percent fines (material passing No. 200 sieve) by weight relative to the fraction finer than the 3/4 —inch sieve for use during placement in wet weather. A higher percentage of fines (not exceeding 10 to 12 percent) .may be allowed for placement during periods of prolonged dry weather. Structural fill should be- placed in loose lifts not exceeding 10 inches in thickness. Each lift should be conditioned to the proper moisture content and compacted to the specified density using vibratory equipment. The on -site soils contain a high percentage of fines and are signifi cantly above the optimum moisture content for compaction.a We recommend that on —site soils not be used as structural fill. V We recommend that the sides of any temporary excavations other than shallow drainage ditches be sloped no steeper than 1 -1/2:1 (horizontal to vertical). Permanent cut slopes and slopes in structural- fill should be made at 2:1 or flatter and should be planted or hydroseeded as soon as U�► possible to minimize erosion. 1 /,�- We recommend that a representative from GeoEngineers, Inc. be present during site preparation and earthwork: to observe the work and perform representative in—place density tests to evaluate if the recommended com- paction criteria are being achieved.' . FOUNDATION SUPPORT Spread footings should be founded in the medium dense sand and dense or hard glacially consolidated soils, or on compacted structural fill. We TUB Colorado Corporation January 28, 1987 Page 6 recommend minimum widths of 16 inches and 24 inchesi for continuous and isolated spread footings,`respectively. The minimum depth of embedment for all footings should be 18 inches.I For foundations designed and constructed as recommended, an allowable bearing pressure of 2000 pounds per square foot may be used. This value applies to the total of dead and long -term live loads exclusive of the weight of the footing and any overlying backfill. This value may be increased by one -third when considering wind or seismic loads. We estimate that footing settlements will be less than 1/2 inch. We anticipate that the exposed bearing surfaces in. excavations will become softened or disturbed if not carefully protected from exposure to moisture and construction activities. Therefore, we recommend that these excavations be made during periods of dry weatheq and the footings poured onl the same day as excavated.; If this is not practical, the excavations should be protected from rainfall. If the bearing soils become softened, the disturbed soils should be excavated and replaced with structural fill and compacted to at least 95 percent of the maximum dry density as determined by ASTM D- 1557.' FLOOR SLAB SUPPORT The sand and silt soils will provide satisfactory support for on -grade slabs'if they are not disturbed by construction activities. Disturbed areas should be repaired in the same manner as in footing excavations. Slabs may also be supported on structural fill placed and compacted to 95 percent of maximum dry density. We recommend that a base course layer of imported clean granular fill or clean crushed rock at least 4 inches thick be placed to form a capillary break beneath the slab .d A positive hydraulic connection should be provided between the base course layer and the footing drain system recommended in a subsequent section. This connection should be on the downhill side of the. residences. A vapor barrier should also be installed to minimize the potential for migration of moisture through the slabs. TUB Colorado Corporation January 28, 1987 Page 7 DRAINAGE We recommend that surface runoff be directed to a storm drainage system. Concentrated runoff should be prevented from flowing down slopes below the residences or driveways. This should be accomplished by providing a system of curbs, gutters and catch basins. Roof, pavement and foundation . drains should be 9nected to a tightline disposal system. Roof and founda- tionndrdIns should not be combined around structures. A permanent subsurface drainage system should be implemented around the ElEihery of cut areas.. The drain system should consist of perforated, drains installed at the outside base of the perimeter footings. These drains should consist of slotted PVC pipe surrounded by 6 inches of pea gravel wrapped in filter fabric and connected by a'tightline system sloped to drain to an appropriate disposal point.4 PAVEMENTS Pavement subgrade areas should be prepared as described under SITE PREPARATION. The pavement subgrade soil should be compacted such that the upper 1 foot of soil attains at least 95 percent of the maximum dry density. Access roads and paved areas should be underlain by at least 6 inches of clean sand and gravel or crushed rock fill. For the expected light vehicular traffic, we recommend an asphalt concrete paving thickness of 2 inches. SLOPE STABILITY Landslides have occurred in the slope north of Slade Way where unfavor- able conditions such as steep slopes and seepage occur. We did not identify any significant signs of instability on the project site, although there may be some shallow, surficial soil creep. Based on our observations, it is our opinion that the overall slope in the immediate vicinity of the site is stable. Construction of residences miy result in a temporary increase in erosion. Some localized sloughing may .1lso be encountered inemporar y cuts particularly if seepage zones are encountered. THB Colorado Corporation January 28, 1987 Page 8 USE OF THIS REPORT We have prepared this report for use by Barghausen Consulting Engineers, Inc. and the THB Colorado Corporation in design of a portion of this project. The data and report should be provided to prospective contractors for their bidding or estimating purposes, but our report, conclusions and interpreta- tions should not be construed as a warranty of the subsurface conditions. The design details are not known at the time of preparation of this report. As your design develops, we expect that additional consultation will be necessary to provide for modification or adaptation of our recommen -: dations.* When the design has been finalized, we should be retained to review the final design and specifications to see that our recommendations have been interpreted and implemented as intended. The scope of our services does not include services related to construc- tion safety precautions and our recommendations . are not intended to di,rect:he contractor's methods, techniques sequence procedures except as specifi- cally described in our report for consideration in design'. There are possible variations in subsurface conditions between the explorations and also with time. A contingency for unanticipated conditions should be included in the budget and schedule. Sufficient monitoring, testing and consultation by our firm should be provided during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork and foundation installation activi- ties comply with contract plans and specifications. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in this area at the time the report was prepared. No other conditions, express or implied, should be understood. THB Colorado Corporation January 28, 1987 Page 9 The conclusions and recommendations in this report should be applied in their entirety. If there are any questions concerning this report or if we can provide additional services, please call. ,P •..t� 4:"i.""7,„,,,.... j'.rjn ,i,,! () /or A.G. � F h `. s**) 1.‘r" , . ■ l '_ a Oct ts1 HRP:JKT:wd Attachments Three copies submitted Yours very truly, GeoEngineers, Inc. \ %Ire/Pt -)I• 17i"-AM44,f-- Herbert R. Pschunder Pro _ ct Engineer K. Tuttle Principal w 4 Property line a ti 4 3 \\\\\\\ \\\ e�,. 01 S. (proptoird) rt N p 80 1 KEY: *1 TEST PIT NUMBER AND LOCAT APPROXIMATE AREAS OF'SHAL STANDING WATER l60 SCALE IN FEET GEI 85 -85 SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS GROUP SYMBOL GROUP NAME COARSE GRAINED SOILS MORE THAN 60% RETAINED ON NO. 200 SIEVE GRAVEL MORE THAN 60% OF COARSE FRACTION RETAINED ON NO. 4 SIEVE CLEAN GRAVEL GW WELL - GRADED GRAVEL, FINE TO COARSE GRAVEL GP POORLY-GRADED GRAVEL GRAVEL WITH FINES GM SILTY GRAVEL GC CLAYEY GRAVEL SAND MORE THAN 50% OF COARSE FRACTION PASSES NO. 4 SIEVE CLEAN SAND SW WELL - GRADED SAND, FINE TO COARSE SAND SP POORLY - GRADED SAND SAND WITH FINES SM SILTY SAND SC CLAYEY SAND FINE GRAINED SOILS MORE THAN 60% PASSES NO. 200 SIEVE SILT AND CLAY LIQUID LIMIT LESS THAN 60 INORGANIC ML SILT CL CLAY ORGANIC OL ORGANIC SILT. ORGANIC CLAY SILT AND CLAY LIQUID LIMIT 50 OR MORE INORGANIC MH SILT OF HIGH PLASTICITY. ELASTIC SILT CH CLAY OF HIGH PLASTICITY. FAT CLAY ORGANIC OH ORGANIC CLAY, ORGANIC SILT HIGHLY ORGANIC SOILS PT PEAT NOTES: 1. FIeId classification Is based on visual examination of soil in general accordance with ASTM D2488 -83. 2. Soil classification using laboratory tests is based on ASTM D2487 -83. 3. Descriptions of soil density or consistency are based on Interpretation of blowcount data, visual appearance of soils, and /or test data. SOIL MOISTURE MODIFIERS: Dry - Absence of moisture, dusty, dry to the touch w, Moist - Damp, but no visible water Wet - Visible free water or saturated, usually soil Is obtained from below water table .w, P.. GeoEnglneers I11 #% ore."41 SOIL CLASSIFICATION SYSTEM I GE! 68 -85 DEPTH BELOW GROUND SURFACE (FEET) GROUP SOIL CLASSIFICATION SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT 1 APPROXIMATE ELEVATION: 265 FEET 0 - 1.0 FOREST DUFF 1.0 - 2.0 ML MOTTLED BROWN AND GRAY SANDY SILT WITH GRAVEL (SOFT TO MEDIUM STIFF, WET) 2.0 - 6.0 SM BROWNISH GRAY SILTY FINE SAND WITH GRAVEL (MEDIUM DENSE TO DENSE, MOIST)(GLACIAL TILL) TEST PIT COMPLETED AT 6.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED AT 1.0 AND 2.0 FEET DISTURBED SAMPLES OBTAINED AT 1.5 AND 4.0 FEET 0 - 1.0 1.0 - 3.0 3.0 - 7.0 0 - 1.0 1.0 - 3.0 3.0 - 6.0 TEST PIT 2 APPROXIMATE ELEVATION: 282 FEET FOREST DUFF SM SM MOTTLED BROWN AND CRAY SILTY FINE SAND WITH GRAVEL (LOOSE, WET) GRAY SILTY FINE SAND WITH GRAVEL (MEDIUM DENSE, MOIST) TEST PIT COMPLETED AT 7.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED AT 1.0 AND 3.0 FEET TEST PIT 3 APPROXIMATE ELEVATION: 290 FEET FOREST DUFF SM SM MOTTLED BROWNISH GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, WET) BROWN SILTY FINE SAND WITH OCCASIONAL GRAVEL (MEDIUM DENSE, WET) TEST PIT COMPLETED AT 6.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED FROM SURFACE TO 3.5 FEET w• DISTURBED SAMPLED OBTAINED AT 4.0 FEET TEST PIT 4 APPROXIMATE ELEVATION: 290 FEET 0 - 1.0 FOREST DUFF 1.0 - 5.5 SM MOTTLED BROWN AND GRAY SILTY FINE SAND (LOOSE TO MEDIUM DENSE, MOIST TO WET) 5.5 - 8.0 SM BROWNISH CRAY SILTY FINE SAND (MEDIUM DENSE, MOIST) TEST PIT COMPLETED AT 8.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED AT 3.0 FEET DISTURBED SAMPLE OBTAINED AT 6.0 FEET THE ELEVATIONS AND DEPTHS ON THE TEST PIT LOGS, ALTHOUGH SHOWN TO 0.1 FEET, ARE BASED ON AN AVERAGE OF MEASUREMENTS ACROSS THE TEST PIT AND SHOULD BE CONSIDERED ACCURATE TO 0.5 FEET. GeoEngineers qpio, Incorporated LOG OF TEST PIT FIGURE 3 1 GEI 68-85 DEPTH BELOW GROUP SOIL GROUND SURFACE CLASSIFICATION (FEET) SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT 5 APPROXIMATE ELEVATION: 286 FEET 0 - 2.0 FOREST DUFF 2.0 - 5.0 SP -SM BROWN FINE SAND WITH SILT (LOOSE, MOIST TO WET) 5.0 - 7.0 SP BROWN FINE SAND WITH OCCASIONAL GRAVEL (MEDIUM DENSE, MOIST) TEST PIT COMPLETED AT 7.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED FROM SURFACE TO 3.0 FEET DISTURBED SAMPLES OBTAINED AT 3.0 AND 6.0 FEET 0 - 0.5 0.5 - 2.0 2.0 - 4.0 TEST PIT 6 APPROXIMATE ELEVATION: 283 FEET FOREST DUFF SM SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST) GRAYISH BROWN SILTY FINE SAND WITH GRAVEL (MEDIUM DENSE , MOIST) TEST PIT COMPLETED AT 4.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED DISTURBED SAMPLE OBTAINED AT 3.0 FEET TEST PIT 7 APPROXIMATE ELEVATION: 272 FEET 0 - 2.0 FOREST DUFF 2.0 - 4.0 SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH OCCASIONAL GRAVEL (LOOSE, MOIST) 4.0 - 6.0 SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH OCCASIONAL GRAVEL (MEDIUM DENSE, MOIST) TEST PIT COMPLETED AT 6:0 "FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED TEST PIT 8 APPROXIMATE ELEVATION: 260 FEET 0- - 4.0 SM BROWN SILTYFINE SAND WITH ROOTS, ROCKS AND DEBRIS (LOOSE, WET)(FILL) 4.0 - 5.5 SM MOTTLED LIGHT BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, WET) 5.5 - 7.0 SM LIGHT BROWN SILTY FINE SAND (MEDIUM DENSE, MOIST) TEST PIT COMPLETED AT. 7.0 FEET ON 1/20/8.7 SLIGHT GROUND WATER SEEPAGE OBSERVED AT 4.0 FEET �% GeoEngineers kwIncorporated LOG OF TEST PIT FIGURE 4. GEI 68-85 DEPTH BELOW GROUND SURFACE (FEET) GROUP SOIL. CLASSIFICATION SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT 9 APPROXIMATE ELEVATION: 238 FEET 0 - 2.0 FOREST DUFF 2.0 - 3.0 SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, WET) 3.0 - 7.0 ML LIGHT BROWN SILT WITH SAND (HARD, MOIST) TEST PIT COMPLETED AT 7.0 FEET ON 1/20/87 GROUND WATER SEEPAGE OBSERVED FROM SURFACE TO 3.0 FEET DISTURBED SAMPLE OBTAINED AT 6.5 FEET 0 - 1.5 1.5 - 4.0 4.0 - 7.0 0 - 1.0 1.0 - 3.0 3.0 - 6.0 TEST PIT 10 APPROXIMATE ELEVATION: 238 FEET FOREST DUFF SM ML MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST TO WET) TAN SILT WITH SAND (HARD, MOIST) TEST PIT COMPLETED AT 4.5 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED TEST PIT 11 APPROXIMATE ELEVATION: 234 FEET FOREST DUFF SM SM LIGHT BROWN SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST) BROWNISH GRAY SILTY FINE SAND WITH GRAVEL (DENSE, MOIST) (GLACIAL TILL) TEST PIT COMPLETED AT 7.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED TEST PIT 12 APPROXIMATE ELEVATION: 255 FEET FOREST DUFF MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST) TAN SILT WITH SAND (HARD, MOIST) TEST PIT COMPLETED AT 6.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED SM ML 4 -1 GeoEngineers 0� Incorporated LOG OF TEST PIT FIGURE 5 GEI 68 -85 DEPTH BELOW GROUND SURFACE (FEET) 0 - 3.0 3.0 - 6.0 GROUP SOIL CLASSIFICATION SYMBOL LOG OF TEST PIT DESCRIPTION TEST PIT 13 APPROXIMATE ELEVATION: 220 FEET SM BROWN SILTY FINE SAND WITH ROOTS AND DEBRIS (LOOSE, WET) SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (DENSE, MOIST) (GLACIAL TILL) TEST PIT COMPLETED AT 6.0 FEET ON 1/.20/87 NO GROUND WATER SEEPAGE OBSERVED • TEST PIT 14 APPROXIMATE ELEVATION: 200 FEET 0 - 1.5 FOREST DUFF 1.5 - 3.0 SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST) w• 3.0 - 5.0 SM GRAYISH BROWN SILTY FINE SAND WITH GRAVEL (DENSE, MOIST) (GLACIAL TILL) TEST PIT COMPLETED AT 5.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED 0 - 1.0 1.0 - 3.0 3.0 - 5.0 TEST PIT 15 APPROXIMATE ELEVATION: 208 FEET FOREST DUFF SM SM MOTTLED BROWN AND GRAY SILTY FINE SAND WITH GRAVEL (LOOSE, MOIST) BROWNISH CRAY SILTY FINE SAND WITH GRAVEL (DENSE, MOIST) (GLACIAL TILL) TEST PIT COMPLETED AT 5.0 FEET ON 1/20/87 NO GROUND WATER SEEPAGE OBSERVED •<1,0,/,..4 GeoEnglneers kl Incorporated LOG OF TEST PIT FIGURE 6 Test Pit 1 1 3 4 5 5 6 9 FIELD MOISTURE CONTENT DATA Sample Depth (Feet) 1.5 4.0 4.0 6.0 3.0 6.0 3.0 6.5 Moisture Content Soil Type (Percent) SM SP -SM SP -SM SP SP SM ML 23.1 19.1 27.4 31.5 19.7 20.7 15.6 25.2 •\�� GeoEngineers Incorporated FIELD MOISTURE CONTENT DATA FIGURE 7 • • JOEL E. HAGGARD ATTORNEY AND COUNSELOR -AT -LAW SUITE 2426, FINANCIAL CENTER 1215 FOURTH AVENUE SEATTLE, WASHINGTON 98161 (206) 682 -5635 January 26, 1987 Ms. Moira Carr Bradshaw City of Tukwila 6200 Southcenter Blvd. Tukwila, Washington 98188 Dear Moira: An-HUI)) JAN 21 198/ CITY TUKvv(LA PLANNING DEPT. I P- 17150.12 We received a copy of your January 8, 1987 memorandum regarding the Silver View Ridge preliminary plat. Please forward to me a copy of the applicant's Environmental Checklist and your SEPA determination. Please add my name to the list of interested parties so I will receive continued information on the plat. JEH /mk 4368D Sincerely' Jo -1 Haggard • • BARGHAUSEN CONSULTING ENGINEERS, INC. "Land Planning, Survey, and Design Specialists" January 21, 1987 Moira Carr Bradshaw Associate Planner City of Tukwila Planning Department 6200 Southcenter Boulevard Tukwila, WA 98188 Re: Response to Letter of January 12, 1987, Regarding Silver View Our Job No. 2262 Dear Moira: LdL L V A E 7,4 N 2' i•87 CITY OF TUKVVILA PLANNING DEPT. I appreciate your letter of January 12, 1987, outlining the conditions that need to be met for processing of the above - referenced application in the City of Tukwila. I would like to respond to your letter and let you know where we stand with regard to these issues. 1. We have just completed the field work for the soil investigation, and a complete geotechnical report addressing construction on the site and the stability of 54th Avenue South will be provided to the city, hopefully, prior to the February 4, 1987, deadline. This report will also address the concerns outlined in the January 12 letter, as well as comments from our meeting with staff in your office. 2. Our office is currently in the process of completing the drainage analysis, which also should be available prior to February 4. 3. I am enclosing a copy of a letter received from King County Water District No. 75 indicating that water is available to the project from their district without difficulty. We are independently pursuing the Developer Extension Agreement process with the district to initiate the design of the improvements. I believe this should satisfy your requirement for a letter of availability from the water district. 6625 South 190th, #102 • Kent, Washington 98032 • (206) 872 -5522 Moira Carr Bradshaw Associate Planner City of Tukwila Planning Department mltrinT [2s 1987 CITY OF TUKWILA PLANNING DEPT. -2- January 21, 1987 4. I have contacted officials from the Puget Sound Power and Light Company in their Renton office and have verified that power will be available to the project from their office. They do not express any concerns with regard to the availability of power, and a letter will be forthcoming in the near future. As soon as that letter is available, I will forward it to your office. 5. We are currently completing a survey of the subject property, and we will be locating all significant trees on the site so that these can be noted on the improvement plans. Also, we will be completing a survey of the frontage improvements along 54th Avenue South in order to determine what improvements will need to be made to this street for the roadway and for the storm system. It should also be noted that we are in the process of securing a title report for the subject property which hopefully will be available some time within the next two to three weeks. The plat certificate that we have already provided should summarize all encumbrances on the title to the property, including easements of record. Typically these certificates are used by King County as title certificates for plat recording. I do not believe that a title insurance policy will generate any other information than what is shown on the plat certificate provided by the Chicago Title Insurance Company. I hope this brings you up to date on our procedures with regard to this project. If you have any questions or comments, please let me know. I will continue to forward information to you as it becomes available. Thank you. Respectful Thomas A. Barghausen, P.E. President TAB /sm C217.52 enc: Copy of Letter from Water District No. 75 cc: Mr. Dana B. Mower, Barghausen Consulting Engineers, Inc. GEORGE L. BLOMBERG, President • , ,.DIN N. CALDWELL. Secretary JERRY P. HARRIS, Commissioner • KEN HALL. General Manager PEGGY BOSLEY, Office Manager DUANE HUSKEY, Operations Manager Wafer 2iitrict no. 75, _lying C. • Telephone 824.0375 January 14, 1987 P.O. Box 68100, Riverton Heights Station Offi SEATTLE, WASHINGTON 98168 Mr. Thomas A. Barghausen, P.E. President Barghausen Consulting Engineers, Inc. 6625 S. 190th, Suite #102 Kent, WA 98032 Re: Your 12/29/86 letter on Silver View Ridge Dear Tom: e: 1 11 21.E �U E D AB;,, t�h1 e5 1987 CITY OF TUKWILA PLANNING DEPT. Please find enclosed for your use a copy of our standard "Application for :Permission to Construct Extensions to Distribution System of Water District No. 75... ". I will respond to each of your questions as they were submitted to us and end with an additional comment: 1. This site is currently in our service area boundary. No annexation or' other boundary adjustment will be necessary. ' 2. There is sufficient fire flow for this site at our main that ends at the hydrant on S. 166th St. (just east of 53rd Avenue S.). That hydrant, by the way, is fed by an 8" main rather than a. 6" main shown on your preliminary plat. 3. With the successful completion of the Developer's Extension and in accordance with our Conditions and Standards, all assessment connection charges and all other fees will be paid for. There are no hidden charges on this. plat. They will simply have to come in and apply for individual meters for each lot. We have gone to a new system where the developer's con- tractor installs the service lines to the meter and we simply hang the meter in the meter box for a standard fee. 4. Finally, please note that the City of Tukwila has a relatively unusual hydrant spacing standard, in which you will be required to have a fire hydrant within 300 feet of the back of each residence as built in this plat. Please check your hydrant spacing with the fire marshall and show us a fire marshall's approved stamp on the drawing at some point in time during the development of plans for this property. • • Mr. Thomas A. Barghausen, P.E. January 14, 1987 Page 2 I hope this answers all of your questions. If it does not, please let me know. It was nice talking with you again. Very truly yours, /‘ DUANE HUSKEY,'P.E. Manager Engineering & Operations DH:w cc: Mr. Ken Hall, General Manager, KCWD #75 Ms. Moira Carr Bradshaw, City of Tukwila, Planning Dept. 6200 Southcenter Boulevard, Tukwila, WA 98188 • • APPLICATION FOR PERMISSION TO CONSTRUCT EXTENSIONS TO DISTRIBUTION SYSTEM OF WATER DISTRICT NO. 75, KING COUNTY, WASHINGTON (ENGINEERING SELECTED BY DEVELOPER) The undersigned hereby makes application to Water District No. 75, King County, Washington, for permission to construct and install a water main and connect to the District's water system, and makes the following representations and agreement, to wit: 1. The proposed mains or additions will be installed in roads under the District's franchise or other approved ways, and shall be for the use and benefit of the following described property, which is owned by the applicant or other persons who are contributing to the cost thereof. DESCRIPTION OF PROPERTY: 2. The proposed line to be approximately lineal feet, shall be installed in accordance with plans approved by the District's 'Engineer and in accordance with Standards and Condi- tions for Construction Extensions to the Water System adopted November 16,'.1983 (Resolution No. 83- 11 -16B, including amendments if any), by the Board of Commissioners of said District, which are on file in the District's office, the terms of which by this reference are made a part hereof. 3. The Developer will select his own engineer and be responsible for his payment. Said engineer shall prepare the Contract Plans. The Water District, however, shall be paid at the current, standard hourly rate plus costs and will require a $1,000 cash deposit before work can be initiated. The Water District Engineer shall be responsible for the following items: a) General consultation with the Developer regarding the requirements of the Water District, including review of the Proposal, Statement of Water District No. 75 charges, Bill of Sale, and Easement or Easements, if any, to be prepared by the Developer's Engineer. b) Verify Fire Marshall's approval of Project Plans (plans to be submitted to Fire Marshall by Developer or his engineer). c) Reviewing the Plans of the Developer for compliance with the Conditions and Standards %;),frnie/ 3 d) Obtain erasable mylar(s) and eight (8) copies of plans approved by District Engineer. e) Application for state, county or city permits. (Permit and inspection fees are to be paid by Developer). f) Staking proposed water main or inspection of the field layout of the Developer's design for compliance with the Contract Plans. g) Inspection of the construction in progress, for compliance with the Conditions and Standards of Water District No. 75. h) Inspection of the pressure tests, and obtaining water purity samples. (Sampling bottles to be paid for by the Developer). i) Final inspection of the completed water main extension for acceptance by the Water District. j) Providing administrative documentation for Water District No. 75 records, including Kroll map revisions, as required. If, after authorizing the Water District Engineer to commence these tasks, the Developer decides not to complete the proposed project, the Water District shall receive payment from the Developer computed on an hourly basis for all services per- formed. The Developer agrees to install the improvement in accordance with the standards prescribed by the District. The Developer also agrees to provide a Performance - Maintenance Bond (in the amount of 25% of the Contractor's bid price for the improve- ment) to the Water District prior to beginning construction. The Developer is also responsible for the installation of service lines and appurtenances as set forth in the drawings and specifications. 5. The Developer's attention is directed to certain areas in the District where pressures are relatively high. It is his responsibility to provide individual pressure reducing valves in these areas. 6. Upon completion of the improvement and upon the approval thereof by the Water District Board of Commissioners, a Bill of Sale in form approved or furnished by the District, together with a valid deed to any Easement required in connection there- with shall be delivered to the District. Upon acceptance by the Water District, such extension shall be subject to the control, use and operation of the Water District, which may apply thereto all regulations, conditions or service, and make such charges therefore as the Board of Commissioners of said District deems reasonable and proper. Water will not be furnished to any new developer until all requirements are completed and all Water District or other bills connected with this extension have been paid. DATED AT , Washington, this day of , 19 DEVELOPER ADDRESS PHONE Upon compliance with the above terms and the conditions of the contract documents furnished by the District to the above named applicant,: Water District No. 75 will accept said extension and furnish water service thereto. WATER DISTRICT NO. 75, KING COUNTY BY 5 r City of Tukwila 6200 Southcenter Boulevard Tukwila Washington 98188 (206) 433 -1800 Gary L. VanDusen, Mayor January 12, 1987 TOM BARGHAUSEN Barghausen Consulting Engineers 6625 So. 190th St., #102 Kent, WA 98032 . RE: SILVER VIEW ESTATES Dear Mr. Barghausen: To follow up on our meeting of January 7, 1987, I am sending a written request for the additional information that the City needs to complete its environmen- tal review. In order to aim for the February 26th Planning Commission Hearing, the information should be received by February 4. You may also request early notice of whether the City considers issuance of a determination of significance likely for the proposal. First, a geotechnical report of the site and 54th Avenue will be required. The roadway does have a history of recent slides. The report should address this issue as well as soils, surface and subsurface hydrological con-. ditions, and the use of vegetation on the site. Second, an analysis of the adequacy and condition of the 0 storm drain system including WSDOT facilities receiving this water should be researched and a proposal made regarding the subdivision's discharge. The carrying capacity and maintenance of the state's facilities are necessary. Third, adequacy of water and power availability will need to be verified by Water District No. 75 and Puget Power respectively. Fourth, upgrading the existing storm system and road access will need to be proposed by the applicant. Cross sections and site layout plans for the street and storm system will need to be submitted. Finally, according to our subdivision code every reaso- nable effort shall be made to preserve existing trees. Therefore a survey of the significant .trees (8" or greater) will be required along with a removal /retention plan. ..f • TOM BARGHAUSEN Barghausen Consulting Engineers January 13, 1987 Page 2 Regarding the plat application, several items should be shown on a revised plat per Tukwila Municipal Code 17.12.030 2 (b): 1. Dotted lines of the existing parcels underlying the proposed plat and any existing utilities or easements within the property should be noted. 2. The boundary lines of adjacent lands should also include the properties land use classifications. 3. The streets should be renamed So. 165th Place and 53rd Place South. A design consideration that could be helpful in lot layout and design would' be to create one or two private access roads out of 53rd Ave. Court, north of its intersection, with So. 165th Court. Design standards for a private road would be minimum width of 30, maximum length of 150 feet, and no more than 4 lot access. Finally a short plat certificate is not a satisfactory substitute to the required title report due to the necessity of full disclosure of all ease- ments and encumbrances on the subject site. Enclosed are several documents being transmitted at the request of the City's Senior Engineer, Phil Fraser If you have any questions, please call me at 433 -1848. Yours truly, MCB /co BAR1 -12 Enclosures: Moira Carr Bradshaw Associate Planner Subdivision Code Public Works Water and Construction standards Index of sanitary sewer standard plans Residential /Roadway section Comprehensive Sewer Plan, Chapter V Table 11, 16 Comprehensive Water Plan ' MEMO DRAFT TO Moira Bradshaw FROM: Phil FrasE DATE: January 7, 1987 SUBJECT: Silver View Ridge Development (Job No 2262-Sheet 1 of 1 Control No 86-446 EPI&I File No 354-86 On page 3 under Item No. 10 add "utility permits". Page 4, Item b1 - I question the maximum 20% slope. Prior development, I recall, stated 30-40% maximum slopes • on property. Item B No. 1.d. - incorrect. There is a history of unstable soils in the immediate vicinity on 54th Avenue South which has not been recognized by this environmental document. Item B No 1.e. Maximum cuts/fills in the property limited to 4 or 5 feet is questionable. To provide a required City Standard roadway section in 54th Avenue South may require either a cut of substantially greater magnitude. Also, there needs to be elaboration on rockeries: her they could be used and where structural walls will be required beyond the 4 feet maximum height allowed for rockeries. Item B-1.h. - Proposed measures to reduce control erosion will be determined upon receipt of a geotechnical/ hydrological analysis of the hillside to assure that the existing history of slide condition3is not aggravated by the proposed construction. On page 7, Item 6.c. - Water Runoff: an analysis of the downstream storm drain system, including WSDOT facilities receiving this water into Klikatat/I-5 shall be analyzed for adequacy as part of the storm drainage analysis for this develop- ment. Page 11, Item 8.a. - Current use of the land immediately east of the site is for a public roadway/utility corridor for 54th Avenue South allowing for access, storm drainage and utilities services for this and surrounding properties. Per section 17.12.030 of the preliminary plat procedures for the Tukwila Municipal Code, page 9, Item No 5, it is noted that the names, locations, width and other dimensions of proposed streets, easements, and utilities have not been clearly indicated on the site plan, as required. Page 15, Item 14.a. - "interior access will be provided by streets to be constructed and dedicated to the City". This item does not reflect in terms the City's stamdar-requirements public residential streets, easements and right-of-way on the site plan. In Chapter 17.24.0, Public Rights-of-way (residen- tial) for a cul de sac street,' the roadway right-of-way width shown is 40'. The City's standard plan for residential street improvements in terms of right of-way and easementt does not appear to be reflected on these plans as required under Item 3 of section 17.24.040. On page 16, item 14.d. - Also included will be the necessary street lighting and undergrounding, power, TV and telephone • • undergrounding. On page 17, item 16 - utilities. In terms of power, Puget Power is the appropriate agency to determine power availability and King County is the appropriate agency to determine whether refuse service is available and Group W Cable, T.V. Cable availability. The water availability: adequacy of water/fire hydrants supply in accordance with Section 17.08.070 of the Tukwila Municipal Code, Item 1.a. - shall be determined through Water District 75. However, the water system to be constructed shall conform to the City of Tukwila Standards provided in the Tukwila Comprehensive Plan V-16 (attached), table 16, including all water lines shall be 6" minimum diameter for residential areas, except 8" minimum diameter for non-loop lines which supply fire hy- drants. The water system shall conform to Water District #75 standards and upon its construction be turned over to and operated by Water Distric't #75. Sewer availability: Per Section 17.08.070 of the Tukwila Municipal Code, Item 1.B. - Sewer availability is determined by the Public Works to be adequate (sewers constructed to serve this property as currently zoned under LID 26). All sanitary sewer mains and services shall be built to the City of Tukwila`s standards and mains turned over to the City of Tukwila upon their construction. However, these sewers will be operated and maintained by the Val Vue Sewer District. The City's standards for the construction of sewers are provided in Chapter 5 of the Tukwila Sewer Comp Plan (attached). • • The receiving public storm system and access on 54th Avenue South from South 166th Street to Slade Way are considered inadequate to facilitate this development. Therefore, upgrading of the public streets and storm system (per the adopted 6-year TIP and Sidewalk Ordinance 1233) shall be required as part of this development. Attachments (3) CITY OF TUKWILA PERMIT NUMBER jc 3s-'f- - CONTROL NUMBER $ -'/q CENTRA PERMIT SYSTEM - .ROPING FORM A. TO: [I BLDG. 1N PLNG. P.W. FIRE Q POLICE [[ P. & R. PROJECT ADDRESS 61 View 62/911 fl�P, S DATE TRANSMITTED C.P.S. STAFF COORD /4/817- ATOR /j/ RESPONSE REQUESTED BY RESPONSE RECEIVED //9/1 PLEASE REVIEW THE ATTACHED PROJECT PLANS AND RESPOND WITH APPROPRIATE COMMENTS IN THE SPACE BELOW. INDICATE CRUCIAL CONCERNS BY CHECKING THE BOX NEXT TO THE LINE(S) ON WHICH THAT CO C 'N I NOTED: i ✓� % li 7 i� a a 0 a 0 a a a 0 a D.R.C. REVIEW REQUESTED [� 1PERWSUBMITTAL REQUESTED PLAN APPROVED [[ PLAN CHECK DATE 1 COMMENTS PREPARED BY C.P.S. FORM 2 CITY OF TUKWILA PERMIT NUMBER eeic 3s�; K CONTROL NUMBER g e -9 . CENTRAL PERMIT SYSTEM - ROUTING FORM TO: [[ BLDG. [ PLNG. [ P.W. (] FIRE 0 POLICE [[ P. & R. PROJECT ei1V& VFekJ ADDRESS d km J S . DATE TRANSMITTED C.P.S. STAFF COORD NATOR /vi(/ RESPONSE RECEIVED PLEASE REVIEW THE ATTACHED PROJECT PLANS AND RESPOND WITH APPROPRIATE COMMENTS IN THE SPACE BELOW. INDICATE CRUCIAL CONCERNS BY CHECKING THE BOX NEXT TO THE LINE(S) ON WHICH THAT CONCERN IS NOTED: RESPONSE REQUESTED BY 0/697 S r i fQ J «I' n Laval fl14. .. f 1 ,,1W ac' //di/ 424 . _ I 1 !ill 1.1 0 Ve, yogi 51/ 1, A, 0 C& r) IQ% p '? ,( r& a 0 0 Q i7 J-197) A // ; hit kA )ardjtd, Altaiea Orc .r-L 4i 64 '1 41/'rx6f:11'1 1 ,0_4'.( ig, LaA,.f/ ./ b. A t 6 . � r4 ps i ✓-1-61- rood i oa.I 1-7. 1 i Yl 6 6i A _ iv ni110L1 tt D.R.C. REVIEW REQUESTED PLAN SUBMITTAL REQUESTED PLAN APPROVED [] PLAN CHECK DATE COMMENTS PREPARED C.P.S. FORM 2 .1111 • MEM DEC 31.19R6 Cfi si ENVIRONMOAL HECKLIST PLANNINci A. BACKGROUND 1. Name of proposed project, if applicable: Contrd!'No. 8' ` Epic File No. ,1/-e°(P Fee $100.00 Receipt No. Silver View Ridge 2. Name of applicant: THB Colorado Corporation 3. Address and phone number of applicant and contact person: 6625 Smith 190th, 1d102, Kant, Washingtnn 98031 Thomas A Barghausen 872 -5522 4. Date checklist prepared: December 31, 1986 5. Agency requesting Checklist: City of Tukwila 6.. Proposed timing or schedule (including phasing, if applicable): The project is expected to be approved in the spring of 1987 and construction should be be completed during the summer of 1987. Completion of all of the houses is expected by 1988/1989. 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. No 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. Please refexo previous City of Tukwila File Nos. 79 -22 -SUB for a previous DPtarmination of Nonsignificance issued for the proiect. Al-a� -5(yie goc. /1,97-61 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. No • • 10. List any government approvals or permits that will be needed for your proposal. City of Tukwila preliminary plat and final plat approval. Individual building permits for the residential lots. ✓10 heiVil' ? / 11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. Section E requires a complete description of the objectives and alternatives of your proposal and should not be summarized here. of approximated 6 acres of land currently zoned "R9,6' and "R12.0" in 18 s ngle - family residential lots with an average 1nt size of 10,000 square fed d a minimum lot size of 9,W00 square feet. Ap r= nximateay 700 feet of public roadway will be constructed to city standards, including two cul -de -sacs. All utility services and public improvements will be extended by the applicant. Single - family residential houses will be constructed on the lots in the future. 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including, a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applica- tions related to this checklist. The property is located in the city of Tukwila west of Interstate 5 along 54th Ave. S. approximately 300 feet south.of Slade Way. The property includes a portion of Lots 19, 20 and 21, snsctively. of Block 2 of McMicken Heights No. 1, unrecorded, being a nnrtinn �f_ sPCtinn__211, Township 3 North, Range 4 East, W.M. 13. Does the proposal lie within an area designated on the City's Comprehensive Land Use Policy Pla Map as environmentally sensitive? No -3- TO BE COMPLETED BY APPLICA • Evaluation for Agency Use Only B. ENVIRONMENTAL. ELEMENTS 1. Earth a. General description of the site (circle one): Flat, rolling,, steep slopes, mountainous, other b. What is the steepest slope on the site (approximate percent slope)? 20% c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, muck)? If you know the classification of agricultural soils, specify them and note any prime farmland. The soils on the site are classified as Arent series which consists of Alderwood soils that have been generally subject to urbanization. d. Are there surface indications or history of unstable soils in the immediate vicinity? If so, describe. 4-8061 No •, of y • e. Describe the purpose, type, and approximate quanti- ties b of any filling or grading proposed. Indicate source of fill. Cuts and fills on the property should be limited to 4 or 5 feet in general for road. grading _purposes and some rockeries will be proposed. Individual excavations for utilities may extend to 8 to 10 feet. Fill will be obtained as needed from local gravel pit sources, probably in Renton. . Could erosion 'occur as a result of clearing, construction, or use? If so, generally describe. Vegetation clearing will result in an increase in erosion potential unless mitigated with temporary erosion control measures. This will be limited to impacts on the site since runoff is durected away from existing development. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? Upon completion, approximately 45% of the site will be covered with impervious surfaces. • 2) Could waste materials enter ground or surface waters? If so, generally describe. No Evaluation for Agency Use Only d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: A complete storm drainage system will be construct on the site, including retention if required by the city, in order to mitigate surface water runoff impacts and to generally limit the rate of runoff to the predevelopment condition. 4. Plants a. Check or circle types of vegetation found on the site: X deciduous tree: alder, maple, aspen, other X evergreen tree: fir, cedar, pine, other X shrubs grass pasture crop or grain wet soil plants: cattail, buttercup, bullrush, skunk cabbage, other water plants: water lily, eelgrass, milfoil, other other types of vegetation b. What kind and amount of vegetation will be removed or altered? �- ARAL° ,u at e1 f h v getatib_wi 11 he removed during construction. Major trees outside of the rnadway and building areas will be left as much as Possible c. List threatened or endangered-species known to be on or near the site.. Evaluation for Agency Use Only 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, solor) will be used to meet the completed project's energy needs? Describe whether it will be used for heating, manufacturing, etc. Electricity and natural gas will both be required for the project subject to availability of gas facilities. b. Would your project affect the potgntial use of solar energy by adjacent properties? If so, generally describe. No c. What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy `A impacts, if any: �C�' None are proposed. 7. Environmental Health a. Are there. any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. None 1) Describe special emergency services that might be required. None are required. 2) Proposed measures to reduce or control environ- mental health hazards, if any: None are proposed 411 Evaluation for Agency Use Only d. Will any structures be. demolished? If so, what? N/A e. What is the current zoning classification of the site? R9.6.and R12.0, which are the single- family residential classifications f. What is the current comprehensive plan designation of the site? Single- family residential g. If applicable, what is the current shoreline master program designation of the site? N/A h. Has any part of the site been classified as an "environmentally. sensitive" area? If so, specify. 0 Not to our knowledge i. Approximately how many people would reside or work in the completed project? Approximately 36 to 54 people may reside in the project upon completion of all of the houses. j. Approximately how many people would the completed project displace? None k. Proposed measures to avoid or reduce displacement impacts, if any: None are required 1. Proposed measures to ensure the proposal is com- patible with existing and projected land uses and plans, if any: The proposed single- family residential subdivision is compatible and consistent with surrounding and existing proposed development. • Evaluation for Agency Use Only 9. Housing a. Approximately /how many units would be provided, if any? Indicate hether high, middle, or low - income housing? 18 esidential lots will be developed probably in the upper middl ncome range for housing units. b. Approximately how many units, if any, would be eli- minated? Indicate whether high, middle, or low - income housing. None c. Proposed measures to reduce or control housing impacts, if any: None are proposed '10. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? The tallest structure will be consistent with city code requirements in the residential zone classifications, being two or three stories. b. What views in the immediate vicinity would be altered or obstructed? None c. Proposed measures to reduce or control aesthetic impacts, if any: None are proposed • Evaluation for Agency Use Only 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? General residential lighting from street lights and house lights, as well as automobile lights, will be generated. This will primarily be limited to the evening hours. b. Could light or glare from the finished project be a safety hazard or interfere with views? No c. What existing off -site sources of light or glare may affect your proposal? Lighting from the freeway, as well as lighting from the Southcenter commercial area will be noticeable from the project. d. Proposed measures to reduce or control light and glare impacts, if any: None are proposed 12. Recreation a. What designed and informal recreational oppor- tunities are in the immediate vicinity? There is a City of_Tukwila park located within 1/4 mile to the north of the project. Other formal recreational opportunities are located in the Southcenter area. b. Would the proposed project displace any existing recreational uses? If so, describe. No c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: None are proposed 111 Evaluation for Agency Use Only 16. Utilities a. Circ_l utilities rrently lable at the site: fuss ser , septic system, other. b. Describe the utilities that are proposed for the project, the utility providing the service, and the o .�' general construction activities on the site or_ N in ,J the immediate vicinity which might be needed. V Water is provided by Water District No. 75. Sewer is provided by the City of Tukwila. Gas is provided by Washington Natural Gas. Power is provided by Puget Sound Power and Light.. Telephone is provided by Pacific Northwest Bell. All utilities are generally available to the site, although water will need to be extended approx. 300 feet from the south. C. Signature The above answers are true and complete to the best of my knowledge. I understand that the le.' agency is relying on them to make ij••-cisr% j Signature: Date Submitted: • iz /3i Boo PLEASE CONTINUE TO THE NEXT PAGE. TO BE COMPLETED BY APPLICA• • Evaluation for Agency Use Only E. SUPPLEMENTAL SHEET FOR ALL PROJECT AND NON PROJECT PROPOSALS The objectives and the alternative means of reaching the objectives for a proposal will be helpful in reviewing the aforegoing items of the Environmental• Checklist. This information provides a general overall perspective of the proposed action in the context of the environmental infor- mation provided and the submitted plans, documents, suppor- tive information, studies, etc. 1. What are the objective(s) of the proposal? The objective of the proposal is to develop 18 single - family residential lots in the middle to upper income range taking advantage of the potential territorial view to the east and maintaining some of the natural vegetation on the project. All improvements are intended to be in accordance with city standards and the streets will be dedicated to the public. The development of single- family residential lots is intended to provide available housing for the public and choice of housing opportunities to the public. 2. What are the alternative means of accomplishing these objectives? The property could be developed iindpr an alternative housing concept, such as clustered housing or condominiums. • 3. Please compare the alternative means and indicate the preferred course of action' Alternative development concepts for the property would generally involve types of housing which are inconsistent with surrounding development and inconsistent with the adopted plans of the City of Tukwila. The preferred course of action would be to develop the property in accordance with existing city policies which allow for single - family residential lots of medium to low density. ', ) ITY 'OF TUKWILA CENTRA1 PERMIT SYSTEM - ROUTING FORM TO: BLDG. [ PLNG. [°� P.W. ] FIRE 4 POLICE ❑ P. b R. PROJECT otlt/ YYei_'_J ADDRESS 6.2 ilki/VPJ S DATE TRANSMITTED 8V- C.P.S. STAFF COORD NATOR J/'j1- v RESPONSE RECEIVED nl f. L. PERMIT NUMBER ent 3s-q- CONTROL NUMBER $ 4 -1/4/6 RESPONSE REQUESTED BY 01/417' PLEASE REVIEW THE ATTACHED PROJECT PLANS AND RESPOND WITH APPROPRIATE COMMENTS IN THE SPACE BELOW. INDICATE CRUCIAL CONCERNS BY CHECKING THE BOX NEXT TO THE LINE(S) ON WHICH THAT CONCERN IS NOTED: ❑ POLICE DEPARTMENT CONCERNS: ❑ 1. AVAILABLE PARKING...14C CITES 2 SPACES PER BUILDING...WILL THIS BE SUFFICIENT FOR THE THREE ADULT UNIT OR THOSE OCCASIONS, I.E.., ❑ HOLIDAYS, PARTIES, ETC.. WHEN VISITORS ARE PRESENT OFF -SITE PARKING IN THE VICINITY IS NOT AVAILABLE DUE TO CONFIGURATION OF 0 166 STREET. 54 AVE. OR SLADE WAY. [] 2. DEVELOPER AND BUILDERS SHOULD CONFER WITH CRIME PREVENTION PRACTIONEEF TO REVIEW LATEST METHODS AND TECHNIQUES ON BUILDING SECURITY INTO Q THE PROJECT AND DISCUSSING CRIME PREVENTION THROUGH ENVIRONMENTAL DESIGN. ❑ 3. IMPACT OF ADDITIONAL TRAFFIC ONTO 54th-AVE /SLADE WAY TRAFFIC ROUTE. 0 ❑ 1/5/87 pal D D.R.C. REVIEW REQUESTED [Q PLAN SUBMITTAL REQUESTED El PLAN APPROVED [] PLAN CHECK DATE COMMENTS PREPARED BY C.P.S. FORM 2 CITY OF TUKWILA • PERMIT NUMBER �jc 34r14-St CONTROL NUMBER $ -V1(4 CENTRAL PERMIT SYSTEM - ROPING FORM a • X TO: BLDG. [ PLNG. [ P.W. ( FIRE [� POLICE Q P. & R. PROJECT ed eic View ADDRESS 40011h9 , J DATE TRANSMITTED 16/817.- RESPONSE REQUESTED BY / 9/ #� C.P.S. STAFF COORD TOR �(iL{// RESPONSE RECEIVED PLEASE REVIEW THE ATTACHED PROJECT PLANS AND RESPOND WITH APPROPRIATE COMMENTS IN THE SPACE BELOW. INDICATE CRUCIAL CONCERNS BY CHECKING THE BOX NEXT TO THE LINE(S) ON WHICH THAT CONCERN IS NOTED: D IVO ealIV E NTT AT TF[T T] 14 , 0 0 0 0 0 0 0 0 a a 0 0 0 a 0 0 a D.R.C. REVIEW REQUESTED 0 PLAN SUBMITTAL REQUESTED [j PLAN APPROVED 0 PLAN CHECK DATE y6--/� COMMENTS PREPARED BY D _ OKTFFEA/ C.P.S. FORM 2 CITY OF TUKWILA , • Control # V-00, N CENTRAL PERMIT SYSTEM - INFOR ON TRANSMISSI REQUEST FORM Permit /File #606 3314--14. PROJECT ,iIJL Yt J ADDRESS 1wrn'e 6 STAFF REVIEWER 7e,ra 1 BELOW ARE COMMENTS THAT NEED TO. BE TRANSMITTED TO THE APPLICANT /DEVELOPER. ❑ D 4 0 ❑ •. ke El CPS Tech please contact applicant /developer 7 I contacted applicant/developer Eme) on C) PP er (n P 0 Please follow -up with me on my concerns by (date) (date) CPS FOLLOW -UP 0 Contacted applicant /developer by phone in writing on (date) Distributed copy of letter to file #s: Comments Instructions: Transmit copy of completed form with any correspondence to staff person and appropriate files. CITY OF TUKWILA PERMIT NUMBER SIC 3s -1 ?'& CONTROL NUMBER g, -4,45/6 CENTRALL Q � PERMIT SYSTEM - APING FORM IP X. TO: BLDG. ( PLNG. [l P.W. . FIRE Q POLICE ( P. & R. PROJECT 5, /0e/4" VEAAJ ADDRESS 6-7 d, i , S. DATE TRANSMITTED /017.. C.P.S. STAFF COORD TOR RESPONSE REQUESTED BY RESPONSE RECEIVED PLEASE REVIEW THE ATTACHED PROJECT PLANS AND RESPOND WITH APPROPRIATE COMMENTS IN THE SPACE BELOW. INDICATE CRUCIAL CONCERNS BY CHECKING THE BOX NEXT TO THE LINE(S) ON WHICH THAT CONCERN IS NOTED: Q Q Q Q Q Q Q Q Q Q Q Q Q D.R.C. REVIEW REQUESTED 0 PLAN SUBMITTAL REQUESTED 0 PLAN APPROVED 0 PLAN CHECK DATE ( /,-/''de-;3? COMMENTS PREPARED C.P.S. FORM 2 W HNOR Control No. 4<(.--z/a6 Epic File No. 3 6'/- �L DEC 19861 Fee $100.00 Receipt No. CE -y U , unNVILA pt_ANWENICIrRO MENTAL CHECKLIST A. BACKGROUND 1. Name of proposed project, if applicable: Silver View Ridge 2. Name of applicant: THB Colorado Corporation 3. Address and phone number of applicant and contact person: 6625 South 190th, # #107, Kent, Washingrnn Q 03J T11rIm qA Barghauqpu 872 -5522 4. Date 'checklist prepared: December 31, 1986 5., Agency requesting Checklist: City of Tukwila 6.. Proposed timing or schedule (including phasing, if applicable): The project is expected to be approved in the spring of 1987 and construction should be be completed during the summer of 1987. Completion of all of the houses is expected by 1988/1989. 7. Do you have any plans for future additions, expansion, or further activity related to or connected with this proposal? If yes, explain. No 8. List any environmental information you know about that has been prepared, or will be prepared, directly related to this proposal. lease refer to evious City of Tukwila File Nos. 79 -22 -SUB for a previous Determination of Nonsignificance issued for the proiect. 9. Do you know whether applications are pending for governmental approvals of other proposals directly affecting the property covered by your proposal? If yes, explain. No 10. list any government approvals or permits that will be needed for your proposal. City of Tukwila preliminary plat and final plat approval. Individual building permits for the residential lots. 11. Give brief, complete description of your proposal, including the proposed uses and the size of the project and site. There are several questions later in this checklist that ask you to describe certain aspects of your proposal. You do not need to repeat those answers on this page. Section E requires a complete description of the objectives and alternatives of your proposal and should not be summarized here. Th _r j t-l- invf,lves the subdivision of approximate 6 acres of land currently zoned R9.... and "R12.0" into 18 single - family residential lots-771TE an average 1nt size o,i0.000 square feet and a minimum lot size of 9,600 square feet. Ap. rnximate],v 700 feet of public roadway will be constructed to city stanT578 -§ including two cul -de -sacs. All utility services and public improvements will be Pxtended by the applicant. Single - family residential houses will be constructed on the lots in the future. 12. Location of the proposal. Give sufficient information for a person to understand the precise location of your proposed project, including a street address, if any, and section, township, and range, if known. If a proposal would occur over a range of area, provide the range or boundaries of the site(s). Provide a legal description, site plan, vicinity map, and topographic map, if reasonably available. While you should submit any plans required by the agency, you are not required to duplicate maps or detailed plans submitted with any permit applica- tions related to this checklist. The property is located in the city of Tukwila west of Interstate 5 along 54th Ave. S. approximately 300 feet south of Slade Way. The property includes a portion of Lots 19, 20 and 21,_rgsnectively. of Block 2 of McMicken Heights No. 1, unrecorded, being a . pnrtinn_cd_ Rertinn Z,_Zowaship 23 North, Range 4 East, W.M. 13. Does the proposal lie within an . area designated on the City's Comprehensive Land Use Policy Plan. Map as environmentally sensitive? No TO BE COMPLETED BY APPLICANT Evaluation for Agency Use Only B. ENVIRONMENTAL. ELEMENTS 1. Earth a. General description of the site (circle one): Flat, rolling, �'[ii'i�, steep slopes, mountainous, other b. What is the steepest slope on the site (approximate percent slope)? 20% c. What general types of soils are found on the site (for example, clay, sand, gravel, peat, muck)? If you know the classification of agricultural soils, specify them and note any prime farmland. The soils on the site are classified as Arent series which consists of Alderwood soils that have been generally subject to urbanization. d. Are there surface indications or history of unstable soils in the •immediate vicinity? If so, describe. No e. Describe the purpose, type, and approximate quanti- ties of any filling or grading proposed. Indicate source of fill. Cuts and fills on the property should be limited to 4 or 5 feet in general . for road grading Qurposes and some rockeries will be proposed. Individual excavations, for utilities may extend tc18 to, 10 feet.., Eill will be , obtained as needed from local gravel pit sources, probably in Renton. . Could erosion 'occur as a result of clearing, construction, or use? If so, generally describe. Vegetation clearing will result in an increase in erosion potential unless mitigated with temporary erosion control measures. This will be limited to impacts on the site since runoff is durected away from existing development. g. About what percent of the site will be covered with impervious surfaces after project construction (for example, asphalt or buildings)? Upon completion,. approximately 45% of the site will be covered with impervious surfaces. • • Evaluation for Agency Use Only h. Proposed measures to reduce or control erosion, or other impacts to the earth, if any: Temporary erosion control measures will be installed during construction as required by the City of Tukwila. These measures will consist of silt fences, rock r heck, dam a,;.,.and,.o.the.r_.measures as, required. 2. Air a. What types of emissions to the air would result from the proposal (i.e., dust, automobile odors, industrial wood smoke) during construction and when the project is completed? If any, generally describe and give approximate quantities if known. Air emissions will result from construction equipment on a temporary basis and long term from automobile traffic from residents, within the project. b. Are there any off -site sources of emissions or odor that may, affect your proposal? If so, generally describe. Heavy automobile 'traffic on 1-5 adjacent to the property is the major source of air emissions. c. Proposed measures to reduce or control emissions or other impacts to air, if any: None are proposed. 3. Water a. Surface: 1) Is there any surface water body on or in the immediate vicinity of the site (including year - round and seasonal streams, saltwater, lakes, ponds, wetlands)? If yes, describe type and provide names. If appropriate, state what stream or river it flows into. No • • Evaluation for Agency Use Only 2) Will the project require any.work over, in, or adjacent to (within 200 feet) the described waters? If yes, please describe and attach available plans. No ' 3) Estimate the amount of fill and dredge material that would be placed in or removed from surface water or wetlands and indicate the area of the site that would be affected. Indicate the source of fill material. None 4) Will the proposal require surface water withdrawals or diversions? Give general description, purpose, and approximate quan- tities, if known. No 5) Does the proposal lie within a 100 -year floodplain? If so, note location on the site plan. No 6) Does the proposal involve any discharges of waste materials to surface waters? If so, describe the type of waste and anticipated volume of discharge. No Evaluation for Agency Use Only b. Ground: 1) Will ground water be withdrawn, or will water be discharged to ground water? Give general •description, purpose, and approximate quan- tities, if known. No 2) Describe waste materials that will be discharged into the ground from septic tanks or other sour- ces, if any (for example: Domestic sewage; industrial, containing the following chemicals...; agricultural; etc.) Describe the general size.of the system, the number of such systems, the number of houses to be served (if applicable), or the number of animals or humans the system(sJ are expected to serve. No discharges are anticipated since sewage disposal will be provided by way of public sanitary sewers. c. Water Runoff (including storm water): 1) Describe the source of runoff (including storm water) and method of collection and disposal, if any (include quantities, if known). Where will this water flow? Will this water flow into other waters? If so, describe. The source of water runoff will be from surface flow across impervious surfaces after periods of rainfall. This water will generally flow easterly across the lots and on the roadway system into an approved storm drainage system to be constructed by_the applicant with a discharge to an approved outlet. Evaluation for Agency Use Only 2) Could waste materials enter ground or surface waters? If so, generally describe. No d. Proposed measures to reduce or control surface, ground, and runoff water impacts, if any: A complete storm drainage system will be construct — don the site, including retention if required by the city, in order to mitigate surface water runoff impacts and to generally limit the rate of runoff to the predevelopment condition. 4. Plants a. Check or circle types of vegetation found on the site: X deciduous tree: alder, maple, aspen, other X evergreen tree: fir, cedar, pine, other X shrubs grass pasture _ crop or grain _ wet soil plants: cattail, buttercup, bullrush, skunk cabbage, other water plants: water lily, eelgrass, milfoil, other other types of vegetation b. What kind and amount of vegetation will be removed or altered? AppxoYi. mate1y 90% of the v ear n.. wj l l be removed during construction. Major trees outside of the roadway and building areas will be left as much as possible c. List threatened or endangered species known to be on or near the site.. Nnne Evaluation for Agency Use Only d. Proposed landscaping, use of native plants, or other measures to preserve or enhance vegetation on the site, if any: Individual property owners will introduce a variety of landscaping species, including grasses. trees and shrubs on indivydUal lots in the future. 5. Animals a. Circle any birds and animals which have been observed on or near the site or are known to be on or near the site: birds: hawk, heron, eagle, s, other: mammals: deer, bear, elk, beaver, other: Small rodents and squirrels fish: bass, salmon, trout, herring, shellfish, other: b. List any threatened or endangered species known to be on or near the site. None c. Is the, site part of a migration route? If so, explain. • No. The site is located in a heavily urbanized area adjacent to a major freeway and does not offer a significant wildlife habitat. d. Proposed measures to preserve or enhance wildlife, if any: None are proposed or considered necessary. Evaluation for Agency Use Only 6. Energy and Natural Resources a. What kinds of energy (electric, natural gas, oil, wood stove, color) will be used to meet the completed project's energy needs? Describe whether it will be 'used for heating manufacturing, etc. Electricity and natural gas will both be required for the project subject to of gas 'facilities. ,b. Would your project affect the potential use of solar energy by adjacent properties? If so, generally describe. No c, What kinds of energy conservation features are included in the plans of this proposal? List other proposed measures to reduce or control energy impacts, if any: None are proposed. 7. Environmental Health a. Are there any environmental health hazards, including exposure to toxic chemicals, risk of fire and explosion, spill, or hazardous waste, that could occur as a result of this proposal? If so, describe. None 1) Describe special emergency services that might be required. None are required. 2) Proposed measures to reduce or control environ- mental health hazards, if any: None are proposed Evaluation for Agency Use Only b. Noise 1) What types of noise exist in the area which may affect your project (for example: traffic, equipment, operation, other)? Noise levels are primarily generated by traffic on Interstate 5. 2) What types and levels of noise would be created by or associated with the project on a short - term or a long -term basis (for example: traf- fic, construction, operation, other)? Indicate what hours noise would come from the site. Noise levels from the project will primarily be related to short -term construction - related noises and long -term noises generated by vehicular traffic. 3) Proposed measures to reduce, or control noise impacts, if any: None are proposed. 8. Land and Shoreline Use a. What is the current use of the site and adjacent properties? The existing site is vacant. Surrounding properties to the north, south and west are generally either vacant or developed for single - family residential uses. Property to the west is developed for the Interstate 5 freeway above Southcenter. b. Has the site been' used for 'agriculture? If s'o, describe. No c. Describe any structures on the site. None Evaluation for Agency Use Only d. Will any structures be demolished? If so, what? N/A e. What is the current zoning classification of the site? R9.6 and R12.0, which are the single— familxresidential classifications f. What is the current comprehensive plan designation of the site? Single- family residential g. If applicable, what is the current shoreline master program designation of the site? N/A . h. Has any part of the site been classified as an "environmentally. sensitive" area? If so, specify. Not to our knowledge i. Approximately how many people would reside or work in the completed project? Approximately 36 to 54 people may reside in the project upon completion of all of the houses. Approximately how many people would the completed project displace? None J• k. Proposed measures to avoid or reduce displacement impacts, if any: None are required 1 1.. Proposed measures to ensure the proposal is com- patible with existing and projected land uses and plans, if any: The proposed single- family residential subdivision is compatible and consistent with surrounding and existing proposed development. Evaluation for Agency Use Only 9. Housing a. Approximately how many units would be provided, if any? Indicate whether high, middle, or low- income housing? 18 residential lots will be developed probably in the upper middle income range for housing units. b. Approximately how many units, if any, would be eli- minated? Indicate whether high, middle, or low - income housing. None c. Proposed measures to reduce or control housing impacts, if any: None are proposed '10. Aesthetics a. What is the tallest height of any proposed structure(s), not including antennas; what is the principal exterior building material(s) proposed? The tallest structure will be consistent with city code requirements in the residential zone classifications, being two or three stories. b. What views in the immediate vicinity would altered or obstructed? None c. Proposed measures to reduce or control aesthetic impacts, if any: None are proposed • • Evaluation for Agency Use Only 11. Light and Glare a. What type of light or glare will the proposal produce? What time of day would it mainly occur? General residential lighting from'street lights and house lights, as well as automobile lights, will be generated. This wilt—primarily be limited to the evening hours. b. Could light or glare from the finished project be a safety hazard or interfere with views? No c. What existing off -site sources of light or glare may affect your proposal? Lighting from the freeway, as well as lighting from the Southcenter commercial area will be noticeable from phe project. d. Proposed measures to reduce or control light and glare impacts, if any: None are proposed 12. Recreation a. What designed and informal recreational oppor- tunities are in the immediate vicinity? There is a City of_ Tukwila park located within 1/4 mile to the north of the project. Other formal recreational opportunities are located in the Southcenter area. b. Would the proposed project displace any existing recreational uses? If so, describe. No c. Proposed measures to reduce or control impacts on recreation, including recreation opportunities to be provided by the project or applicant, if any: None are proposed • Evaluation for Agency Use Only 13. Historic and Cultural Preservation a. Are, there any places or objects listed on, or pro- posed for, national, state, or local preservation registers known to be on or next to the site? If sd, generally describe.' No b. Generally describe any landmarks or evidence of historic, archaeological, scientific, or cultural importance known to be on or next to the site. None c. Proposed measures, to reduce or control impacts, if any: None are proposed 14. Transportation a. Identify public streets and highways serving the site, and describe proposed accss to the existing street system. Show on site plans, if any. Access is provided by way of S4th Avenue South directly to the proiect site. Interior access will be provided by streets to be constructed and dedicated to the city. b. Is the site currently served by public transit? If not, what is the approximate distance to the nearest transit stop? No c. How many parking spaces would the completed project have? How many would the project eliminate? At least two off - street parking stalls will be provided for each lot. • • Evaluation for Agency Use Only d. Will the proposal require any new roads or streets, or improv-ements to existing roads or streets, not including driveways? If so, generally describe (indicate whether public or private). Approximately 700 feet,of public. street, including two'cul- de -sacs y will be constructed by the developer on the site. These streets will include curb. gutter. and sidewalk per city standards. e. Will the project use (or occur in the immediate vicinity of) water, rail, or air transportation? If so, generally describe. No f. How many vehicular trips per day would be generated by the completed project? If known, indicate when peak volumes would occur. Approximately 180 vehicle trips per day will be generated by the project, and approximately 18 trips during the peak hour will be generated. Peak -hour volume is expected to occur between 4:30 and 5:30 p.m. 9. Proposed measures to reduce or control transpor- tation impacts, if any: The construction. of the on -site roadway system and improvements to 54th Avenue South adjacent to the property should mitigate impacts from the project. 15.. Public Services a. Would the project result in an increased need for public services (for example: fire protection, police protection, health care, schools, other)? If so, generally describe. The small scale of the project is usa expected to have an adverse impact l_ rP availahte to the site and in the • 1 . . ' general area b. Proposed measures to reduce or control direct impacts on public services, if any. None are proposed fond tho normal agS,ap„saatont of tax dollars. Evaluation for Agency Use Only 16. Utilities a. Circ - utilities rr-ntly a_lable the site: p ser , septic system, other. b. Describe the utilities that are proposed for the project, the utility providing the service, and the general construction activities on the site or in the immediate vicinity which might be needed. Water is provided by Water District No. 75. Sewer is provided by the City of Tukwila. Gas is provided by Washington Natural Gas. Power is provided by Puget Sound Power and Light. Telephone is provided by Pacific Northwest Bell. All utilities are generally available to the site,. although water will need to be extended approx. 300 feet from the south. C. Signature The above answers are true and complete to the best of my knowledge. I understand that the le•.' agency is relying on them to make i -cis Signature: Date Submitted: • /z /3/ Boo PLEASE CONTINUE TO THE NEXT PAGE. TO BE COMPLETED BY APPLICANT Evaluation for Agency Use Only D. SUPPLEMENTAL SHEET FOR NONPROJECT ACTIONS (do not use this sheet for project actions) Because these questions are very general, it may be helpful to read them in conjunction with the list of the elements of the environment. When answering these questions, be aware of the extent the proposal, or the types of activities likely to result from the proposal, would affect the item at a greater intensity or at a faster rate than if the proposal were not imple- mented. Respond briefly and in general terms. Y. How would the proposal be likely to increase discharge to water; emissions to air; production, storage, or release of toxic or hazardous substances; or production of noise? Proposed measures to avoid or reduce such increases are: 2. How would the proposal be likely to affect plants, ani- mals, fish, or marine life? Proposed measures to protect or conserve plants, ani- mals, fish, or marine life are: • Evaluation for Agency Use Only 3.. How would the proposal be likely to deplete energy or natural resources? Proposed measures to protect or conserve energy and natural resourses are: 4. How would the proposal be likely to use or affect environmentally sensitive areas or areas designated (or eligible or under study) for governmental protection; such as parks, wilderness, wild and scenic rivers, 'threatened for endangered species habitat, historic or cultural sites, wetlands, floodplains, or prime farmlands? Proposed measures to protect such resources or to avoid or reduce impacts are: 5. How would the proposal be likely to affect land and shoreline use, inclduing whether it would allow or encourage land or shoreline use incompatible with existing plans? Evaluation for Agency Use Only Proposed measures to avoid or reduce shoreline and land use impacts area: How does the proposal conform to the Tukwila Shoreline Master Plan? 6. How would the proposal be likely to increase demands on transportation or public services and utilities? Proposed measures to reduce or respond to such demand(s) are: 7. Identify, if possible, whether the proposal may conflict with local, state, or federal laws or requirements for the protection of the ehvironment.' • • Evaluation for Agency Use Only 8. Does the proposal conflict with policies of the Tukwila Comprehensive Land Use Policy Plan? If so, what poli- cies of the Plan? Proposed measures to avoid or reduce the conflict(s) are: • TO BE COMPLETED BY APPLICANT Evaluation for Agency Use Only E. SUPPLEMENTAL SHEET FOR ALL PROJECT AND NON PROJECT PROPOSALS The objectives and the alternative means of reaching the objectives for a proposal will be helpful in reviewing the aforegoing items of the Environmental Checklist. This information provides a general overall perspective of the proposed action in the context of the environmental infor- mation provided and the submitted plans, documents, suppor- tive information, studies, etc. 1. What are the objectiv'e(s) of the proposal? • The objective of the proposal is to develop 18 single - family residential lots in the middle to u.•er income _ran :e takin ad ., .•e .- .. ntial territorial view to the east and maintaining some of the natural vegetation on the project. All improvements are intended to be in accordance with city standards and the streets will be dedicated to the public. The development of single - family residential lots is intended to provide available housing for the public and choice of housing opportunities to the public. 2. What are the alternative means of accomplishing these objectives? The property could be developed under nn alternative housing concept, such as clustered housing or condominiums. 3. Please compare the alternative means and indicate the preferred course of action: Alternative development concepts for the property would generally involve types of housing which are inconsistent with surrounding development and inconsistent with the adopted plans of the City of Tukwila. The preferred course of action would be to develop the property in accordance with existing city policies which allow for single- family residential lots of medium to.low density. Evaluation for Agency Use Only 4. Does the proposal conflict with policies of the Tukwila Comprehensive Land Use Policy Plan? If so, what poli- cies of the Plan? The proposal does not conflict with existing city policies, and is instead consistent with city policies and zoning on the site and within the surrounding area. Proposed measures to avoid or reduce the conflict(s) are: - . conflicts do not exist with the proposal and existing policies of the City of Tukwila. ... .11 • • • . -23- DECLARATION OR COVENANTS FOR SILVER VIEW ESTATES LOCATED IN TUKWILA, WASHINGTON THIS AGREEMENT is made and entered into this day of 1987, between the City of Tukwila, the Washington Corporation, (hereinafter referred to as the City), and THB Colorado Corporation of Kent, Washington, 6625 South 190th Street, Kent, WA 98032 (hereinafter referred to as the Owner). WITNESSETH WHEREAS, the Owner is the owner of certain real property located generally at the intersection of Slade Way and 54th Place South, and WHEREAS, the Owner has applied for approval of a final plat for the deve- lopment of 22 single - family residential lots, and WHEREAS, the development of said property will create traffic impacts which will necessitate the construction of an approved intersection at Klickitat Avenue and 53rd Avenue South and along Slade Way. NOW, THEREFORE, IN CONSIDERATION OF the mutual benefits and conditions hereinafter contained, the parties hereto agree as follows:, 1. Responsibilities of Owner A. The Owner shall agree to conditions 12, 13, and 14 of the miti- gating measures per EPIC File 354 -86 for Silver View Plat per the environmental review for this project. These improvements are as follows: 1. The Owner shall agree to participate in the intersection improvements at Klickitat Avenue and 51st Avenue South at time of Valley View Estates construction for a percentage of Silver View Estates project average daily vehicle trips (per both developments). Improvements to the intersection are limited to: a. Rechannelization for additional turning movements within intersections including roadway (no signalization required) to within 150 feet of intersection centerline. 2. The applicant shall not protest the formation and shall commit to the construction of future LID for street improvements including roadway, utility underground street lighting, and additional storm drainage improvements as proportionately benefiting their development for street improvement project defined in the 1987 six year traffic improvement plan at Slade Way. 3. The applicant shall execute a Developer's Agreement for the construction of curb, gutter and sidewalk along 54th Avenue South frontage (see attached). DECLARATION OF COVENANTS FOR SILVERVIEW ESTATES Page 2 4. Attachments incorporated herein are itemized as follows: a. Property legal description (Exhibit "A "). b. Sidewalk Agreement (Exhibit "B "). c. Plot plan (Exhibit "C "). d. EPIC file (Exhibit "D "). e. Six year traffic improvement plan (Exhibit "E "). 2. Responsibility of City A. Non - waiver - extensions. Failure of either party to insist on the strict performance of any of the terms of this Agreement shall not be construed as a waiver or relinquishment of that party's right thereafter to strictly enforce any such term, but the same shall continue in full force and effect. B. Binding Effect. This Agreement shall be binding upon the parties, their respective heirs, legal representatives, assigness, transferees and successors. C. Recording. This Agreement shall be a covenant running with the land described on Exhibit "A" attached hereto and incorporated herein as if fully set forth and shall be paid by the Owner. D. Attorneys' Fees. In the event that either party shall commence litigation against the other in order to enforce any term or condition of this Agreement, the prevailing party in such litigation shall be entitled to recover its costs, including reasonable attorneys fees. E. Entire Agreement. This agreement contains the entire understanding between the parties hereto, and no other agreements, oral or otherwise, regarding the subject matter of this Agreement shall be deemed to exist or to bind any of the parties hereto or to have any other force or effect. DATED THIS DAY OF , 19 OWNERS: DECLARATION OR COVENANTS FOR SILVERVIEW ESTATES Page 3 The foregoing Agreement is accepted by the City of Tukwila this day of , 19 STATE OF WASHINGTON) )ss COUNTY OF KING ) CITY OF TUKWILA Mayor, City of Tukwila On this day personally appeared before me to be known to be the parties described in and who executed the within AGREEMENT and acknowledged that he /she signed and sealed the same as his /her free and voluntary act and deed for the uses and purposes therein mentioned. GIVEN UNDER MY HAND AND OFFICIAL SEAL THIS DAY OF , 19 Notary Public in and for the State of Washington, residing at STATE OF WASHINGTON) )ss COUNTY OF KING ) On this day personally appeared before me and to be known to be the and of the CITY OF TUKWILA, the corporation that executed the within and foregoing AGREEMENT and acknowledged said instrument to be the free and voluntary act and deed of said corporation, for the uses and purposes therein mentioned, and on oath stated that they were authorized to execute said instrument. OF GIVEN UNDER MY HAND AND OFFICIAL SEAL THIS DAY 25 /MB.SILVIEW , 19 Notary Public in and for the State of Washington, residing at