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Home My WebLink AboutTIC 2019-01-23 Item 2E - Flood Control - Lower Green River Corridor Plan / Flood Hazard Management Plan*11,4 '01 0 0 Allan Ekberg, Mayor Public Works Department - Henry Hash, Director INFOR ATIONAL E ORANDUM TO: Transportation and Infrastructure Committee FROM: Henry Hash, Public Works Director //. BY: Ryan Larson, Senior Program Manager CC: Mayor Ekberg DATE: January 18, 2019 SUBJECT: Surface Water Fund Lower Green River Corridor Plan - Flood Hazard Management Plan ISSUE The King County Flood Control District (Flood District) is beginning work on the Lower Green River Corridor Plan and is accepting comments on the scope of the plan and proposed alternatives. BACKGROUND The King County Flood Control District is preparing a Lower Green River Corridor Flood Hazard Management Plan (Plan) for approximately 21 river miles of the lower Green River that flow through unincorporated King County and the cities of Auburn, Kent, and Tukwila. The goal of the Plan is to provide a long-term approach to reduce flood risk and improve fish habitat while supporting the economic prosperity of the region. The Flood District is also preparing a Programmatic Environmental Impact Statement (PEIS), which will analyze altematives for flood protection that could be included in the plan. The PEIS will evaluate the potential impacts of the projects identified in each proposed alternative. DISCUSSION The Flood District is accepting comments on the Plan and PEIS through January 28, 2019. Staff has reviewed the information provided by the Flood District and is preparing response comments for the Flood District to consider in this effort. Our broad approach to this effort will be to: • Request that all projects throughout the Flood District be prioritized first for life and safety concems and that environmental benefits should be included in all construction projects to minimize the impact of levees to the natural environment. • Request that the Flood District evaluate and quantify their ability to recover Puget Sound Chinook salmon. (See attached draft letter by Puget Sound Salmon Recovery Council) • Request that all future levee projects except for Fort Dent, be constructed to provide a 500-year level of flood protection. • Request that the Fort Dent levee be brought to a 100-year level of flood protection. • Request that the study area be lengthened to include impacts throughout the City and not end at the Black River. • Provide a prioritized list of known Green River flood protection projects throughout the City. This will primarily be made up of known deficiencies along the Tukwila 205 levee with an emphasis on completing these projects first. FISCAL IMPACT None at this time. RECOMMENDATION Staff is seeking Committee approval to finalize and submit the public comment letter. ATTACHMENTS Draft Puget Sound Salmon Recovery Council Letter Lower Green River Corridor - Flood Hazard Management Plan Information. W \ PW Eng \PROJECTS \A- DR Projects \Tukwila 205 \ Corridor Plan\ Info Memo Corridor Plan docx 79 January XX, 2019 King County Flood Control District ATTN: Michelle Clark, SEPA Responsible Official 516 Third Avenue Room 1200 Seattle, WA 98104 RE: Lower Green River Corridor Flood Hazard Management Plan Draft Programmatic Impact Statement Dear Ms. Clark: Since the 1999 listing of Puget Sound Chinook as a Threatened Species, significant local, state, and federal resources have been invested to avert extinction of Puget Sound Chinook. A fundamental need to recover Chinook throughout Puget Sound is increasing and improving rearing habitat of river systems. The Puget Sound Chinook Salmon Recovery Plan identifies the Lower Green River as a significant bottleneck to recovering Puget Sound Chinook salmon due to substantial reduction of rearing habitat and dramatic decrease in the survival of Chinook salmon. It is absolutely critical to increase the rearing habitat of the Lower Green River to recover the Green River Chinook salmon population --and recovery of Chinook salmon Puget Sound -wide. Continued decline in the Green River Chinook salmon population is of regional and statewide concern as its recovery is essential to de -listing Puget Sound Chinook as Threatened and, moreover, avoid losing the Southern Resident killer whale population. The three alternatives identified in the November 26, 2018 Draft Programmatic Environmental Impact Statement (DPEIS) scoping notice will not advance Puget Sound Chinook salmon recovery. The Puget Sound Salmon Recovery Council (SRC) requests that the King County Flood Control District evaluate and quantify their ability to recover Puget Sound Chinook salmon by their ability to recover the Green River Chinook population. The SEPA environmental evaluation and analysis must identify an alternative for flood management of the Lower Green River that is consistent with the Puget Sound Chinook Salmon Recovery Plan. The Puget Sound region cannot afford losing opportunities to reverse declines of salmon and orca. The SRC strongly believes that a narrow approach to long-term flood risk reduction throughout Puget Sound, without appropriately integrating the needs of Chinook salmon recovery, is a significant step backward. To ensure the value of the millions of dollars that have been invested in Puget Sound to recover Chinook salmon, a multiple -benefit approach to floodplain management is imperative for the Lower Green River. 80 KING COUNTY FLOOD CONTN_/L D I S T k I C T Project Descriptio,,' The Lower Green River is susceptible toflooding and flood damage that affects people and residential, commercial, industrial, and agricultural properties along USbanks. The potential impacts and damages ofmajor floodingon peop|e, atnucturea, infrootructure, businesses, and jobs throughout the Lower Green River Valley are substantial. Thaddress these issues, the King County Flood Control District iopreparing aLower Green River Corridor Flood Hazard Management Plan (P|en)for approximately 21 river miles ofthe Lower Green River that flow through the cities of Auburn, Kent, Renton, Tukwila, and unincorporated King County. The goal ofthe Plan imtoprovide along -term approach ioreduce flood risk and improve fish habitat while supporting the economic prosperity ofthe region. See the Study Area map onpage 2. PrograUnN08tic Environmental Impact Statement The District isalso preparingaProgrammatic Environmental Impact Statement (=BS). which will analyze alternatives for flood protection that could be included inthe Plan. The PBGdescribes potential environmental impacts and measures toreduce nr eliminate them. Because each alternative includes n variety offlood protection projects 1hmtnnakeup a ''pnn8nam" of actions, a PBS is being prepared. The PB8will evaluate the potential impacts ofthe projects identified ineach alternative. 47 What are the The "No Action Alternative" ksrequired toobjectively evaluate and compare the other two alternatives. |t would include completing existing projects adopted inthe 2O18-28Capital Improvement Program (Rono|utionRC[)2018'OO.2). ��"�The "&@odera8eGm��Geographic of0wm�amadLevel ~�ofProtection Alternative" would include 3miles ofnew levees and improvements to17miles oy existing levees. The "Greater m�� p��f�to�thIncreased le�lmf ~~� Protection, Integrated Habitat and Recreation, Agricultural Protection Facilities, and Habitat Restoration Project Partnerships Alternative" iothe same aoAlternative 2 with the addition of1Omiles cfnew levees and 2 miles ofnon-structural improvements. Incentives to provide habitat restoration could also bnprovided. Each ofthe alternatives includes continued maintenance of existing flood facilities. Alternatives 2and 8would also include some drainage improvements tOagricultural lands and flood -proofing ofagricultural structures. More detailed descriptions 0fthe alternatives can befound online at: vvvvvv|ovvergnaenaepa.org. Process The PEI8will take about two years to complete. Comment periodsduhng scoping and during review of the Draft PB8will provide opportunities for the public to provide input. iw � 'W" �� 81 'or,rcr— c ^c 9* •10 pzs. "r VE LA so f,.4 0 RAI ANcs PARK, s 213,,,ss st. S 312.th SI s ism st KENT 2cREA ar .0000w .„,c4,10INcIRO Sralikl9 The scoping comment period is from November 28, 2018, to January 29, 2019. Provide your comments in -person; Scoping IVIeeting Wednesday, January 9, 2019 5:00-5:45 p.m. Open House 5:45-7:30 p.m. Presentation and Public Testimony 7:30-8:00 p.m. Open House Green River College Kent Campus 417 Ramsay Way, Room 283 Kent, WA 98032 A Spanish interpreter will be available at the meeting. Habra un interprete de espariol disponible en la reunian. Ifyou would like to request an interpreter for another language, please call 206-775-8778. Please send your written comments to: EMAIL: Iowergreensepa@kingcounty.gov MAIL: King County Flood Control District Attn: Michelle Clark, SEPA Responsible Official 516 Third Avenue, Room 1200 Seattle, WA 98104 Learn more about the PEIS, and the alternatives being studied at www.lowergreensepa.org or by calling 206-263-0602. This document has been provided in English and Spanish. Este document° se facia° en ingles y en espaiiol. f you require a translation in a different language, please call 206-775-8778. SE Lalqt Holm PE1 .34 Lower Green River Corridor Flood Hazard Management Plan and Programmatic Environmental Impact Statement Study Area 115 KING COUNTY FLOOD CONTROL DIS TR ICT The use of the infonnalion in this map is subject to the tams and conctlicns faund at www_kingostraygor:set-visesgishla'Aseenns-oPuse.aspc Your access old use is orationed o n acceptance of these tem* and condlims_ fl Kng Ccuray GS F1309_823Ch,grech_al_xn_rnapal I= Study Area Green River • 30 River Mile City Area 0 2 Miles September 2018 82 KING COU\TY FLOOD CONTROL DISTRICT C r e ice Sc en FLOOD HAZARD MANAGEMENT PM AN AND PROGRAMMATIC'ENVIRO'NMENTAL IMP* STATEMENT A Tukwila No Action Alternative,inc udes following', improved facilities: Type A facility: 0,6 mile'(30%) • Type B facility: 0.57 mile (38%)' • Type C facility: 0.86 mile (42%) No Action Alternative does not include1' any Type D facility projects ternative No Action odsrCOn rol Dist Exhibit 1 Lower Green River Corridor Plan Alternative Framework Draft 10/8/2018 Alternative 1: No Action Maintain Existing Levees and Revetments, Construct 2018-2023 Capital Improvement Program (CIP). Projects with Increased LOP* include Lower Russell, Breda and Gaco-Mitchell. Proposed Flood Facilities with Increased LOP* of 18,800 cfs plus 3' freeboard Flood Facility Type: Type A: Most constrained, riverward embankment side slope of 2.5 to 1 or less; footprint of 100 feet or less Type B: Somewhat flatter stable riverward embankment side slope of 2.5 to 1 or more; footprint of 100 to 150 feet Type C: Levee setback; footprint of 150 feet or more Type D: Physical non-structural Existing Conditions and Facilities: ilt:' 2018-2023 Capital Improvement Program (CIP) Construction PL 84-99 Levee Systems (approx. 17 miles) xi Other Levees and Revetments (approx. 11 miles) Existing Private Levee Shoreline with No Facilities (approx. 14 miles) Green River Mainstem (42 shoreline miles) River Miles (RM) Cities Note: The PL 84-99 levees have an existing LOP* of 12,000 cfs plus variable freeboard. N A 0 0.5 1 2 Miles * Level of Protection (LOP) is defined as the amount of flow expressed as cubic feet per second (cfs) plus freeboard that the flood facility is designed to contain. Assignment of facility type along the shoreline is based on a planning level assessment. Facility type designation is not intended to represent levee alignments nor does it account for feasibility design considerations such as transitions between project types, ties into high ground and discrete locations where adjustments would be made to avoid utilities and infrastructure. (Three alternatives are being studied) 83 KING COU\TY FLOOD CONTROL DISTRICT ewereen erridor m co ver eaten HAZARD. MANAG PLAN AND PROGRAMMATIC ENVIRO N T M NT IrL»OOD �MENT� '' t��I�IENTAI:"IMPACT STA A tornaUvo 2 Moderate Geographic Extent of Increased Level of Protection Alternative 2 includes construction of followiing lengths of new or improved facilities:'' • Type A facility: 10.17 milesl(50%) • Type B facility: 4.68 miles (23%) • Type C facility: 5.41 miles (27%) Alternative 2 would not include any Type D facility projects, except where needed to maintain the current level of protection. Exhibit 2 Lower Green River Corridor Plan Alternative Framework Draft 10/8/2018 Alternative 2 Moderate Geographic Extent of Increased LOP* Proposed Flood Facilities with Increased LOP* of 18,800 cfs plus 3' freeboard Flood Facility Type: Type A: Most constrained, riverward embankment side slope of 2.5 to 1 or less; footprint of 100 feet or less Type B: Somewhat flatter stable riverward embankment side slope of 2.5 to 1 or more; footprint of 100 to 150 feet Type C: Levee setback; footprint of 150 feet or more Type D: Physical non-structural Existing Conditions and Facilities: Other Levees and Revetments (approx. 11 miles) Existing Private Levee Green River Mainstem (42 shoreline miles) River Miles (RM) Cities Note: The PL 84-99 levees have an existing LOP* of 12,000 cfs plus variable freeboard. N A 0 0.5 1 2 Miles * Level of Protection (LOP) is defined as the amount of flow expressed as cubic feet per second (cfs) plus freeboard that the flood facility is designed to contain. Assignment of facility type along the shoreline is based on a planning level assessment. Facility type designation is not intended to represent levee alignments nor does it account for feasibility design considerations such as transitions between project types, ties into high ground and discrete locations where adjustments would be made to avoid utilities and infrastructure. (Three alternatives are being studied) 84 KING COU\TY pa, er Green , � � e FLOOD CONTROL DISTR ICT Corridor Sco in 9 Meeting FLOOD HAZARD MANAGEMENT PLAN /AND PI OGRAMMATIC ENVIRONMENTAL.'' PACT STATEMENT A torn.tvo 3 Greater Geographic Extent with Increased Level of Protection, Integrated Habitat and Recreation, Agricultural Protection Facilities, and Habitat Restoration Project Partnerships Alternative 3 includes construction of follow lengths of new or improved, facilities: • Type A facility: 15.43 miles (49%) • Type B facility: 5.39miles (17%) • Type C facility: 9.08 miles (29%) • Type ID facility: 1.91 miles (6%) -o fltfO Exhibit 3 Lower Green River Corridor Plan Alternative Framework Draft 10/8/2018 Alternative 3 Greater Geographic Extent with Increased LOTP*. Integrated Habitat and Recreation. Agricultural Protection Facilities and Habitat Restoration Project Partnerships. Includes Alternative #2 plus additional areas on both the right and left bank. Proposed Flood Facilities with Increased LOP* of 18,800 cfs plus 3' freeboard Flood Facility Type: Type A: Most constrained, riverward embankment side slope of 2.5 to 1 or less; footprint of 100 feet or less Type B: Somewhat flatter stable riverward embankment side slope of 2.5 to 1 or more; footprint of 100 to 150 feet Type C: Levee setback; footprint of 150 feet or more 1 Type D: Physical non-structural Existing Conditions and Facilities: Other Levees and Revetments (approx. 11 miles) Existing Private Levee Green River Mainstem (42 shoreline miles) River Miles (RM) Cities Note: The PL 84-99 levees have an existing LOP* of 12,000 cfs plus variable freeboard. N A 0 0.5 1 2 Miles * Level of Protection (LOP) is defined as the amount of flow expressed as cubic feet per second (cfs) plus freeboard that the flood facility is designed to contain. Assignment of facility type along the shoreline is based on a planning level assessment. Facility type designation is not intended to represent levee alignments nor does it account for feasibility design considerations such as transitions between project types, ties into high ground and discrete locations where adjustments would be made to avoid utilities and infrastructure. uerT (Three alternatives are being studied) 85 KING COUNTY FLOOD CONTROL D 1 S TRICT 516 Third Avenue • Room 1200 Seadle, 98104 206,296.1020 illib@rkingeountyflootkommLorg WWW. kingvonntythmdrondoliorg Lower Green River Corridor Flood Hazard Management Plan Programmatic Environmental Impact Statement Scoping Comment Form Submit a comment on the PEIS by filling out this form and leaving it in the comment box at today's meeting or by mailing it to the following address by January 29, 2019: King County Flood Control District Attn: Michelle Clark, SEPA Responsible Official 516 Third Avenue Room 1200 Seattle, WA 98104 You can also email comments to LowerGreenSEPAPkingcountv.gov or submit them online at www.lowergreensepa.org. Name: Email Address: Address: Comment: (please feel free to use the back of this form if you need more space) 86 8/30/2018 Flood Facility Project Type A • Riverward side slope < 2.5:1 • Footprint 100' or less 15* TYPICAL OH Ore 0/ OR LESS OHW= ordinary high water > Exposed Flood Wall i 3' TYPAL 8TYPICAL 8" TYPICAL ,,,e;,,,TwerrogAlw.","*LPROP;A`," AP8ApTe., ppTATTIPAPTTP .3,,,FPTO-PWis0 Typi�at F oodwall Not to Scale Illustrative Only 8/30/2018 Flood Facility Project Type B • Riverward side slope >2.5:1 • Footprint 100'-150' OHW= ordinary high water co co v/ 0 Green River 15' 4. —Exposed Flood Wall . „ 6- Pi -CA 'e'er 'Re VARIES, TYPICALLY 100 - 120' 'efieMt.fr Typical Floodwall VARIES, TYPICALLY 120' - 150' Mve,..1URRRO, Not to Scale Illustrative Only 4/23/2018 Flood Facility Project Type C • Riverward side slope 3:1 • Footprint 150' or more OHW Greert River SETBACK LEVEE 1507+ 030HW= ordinary high water co Typical Levee Not to Scale Illustrative Only 4/23/2018 Flood Facility Project Type D Physical Non -Structural c;reen River Example o 1.1114114111 pad and drainage improvements OHW Greert River OHW= ordinary nigh water Up to 3" (other potential measures include wet flood proofing, berms or ring levees) Not to Scale Illustrative Only