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Home My WebLink AboutCOW 2023-04-24 Item 4C - Update - Water Reservoir SiteITEM INFORMATION STAFF SPONSOR: ADIB ALTALLAL ORIGINAL AGENDA DATE: AGENDA ITEM TITLE Water Fund – Water Reservoir Sites Update CATEGORY Discussion Motion Resolution Ordinance Bid Award Public Hearing Other Mtg Date 04/24/23 Mtg Date Mtg Date Mtg Date Mtg Date Mtg Date Mtg Date SPONSOR Council Mayor Admin Svcs DCD Finance Fire P&R Police PW SPONSOR’S SUMMARY During the City of Tukwila’s 2015 Water Comprehensive Plan, the consultant identified that the continued growth within the City no longer meets the Department of Health’s water storage requirements. For the last several years, the City has been evaluating locations for a potential new reservoir. Staff are currently proposing utilizing the site of former Fire Station 52 and looking for direction from Council on next steps. The Committee of the Whole will receive a briefing for discussion only on April 24, 2023. REVIEWED BY Trans&Infrastructure Svcs Community Svcs/Safety Finance & Governance Planning & Community Dev. LTAC Arts Comm. Parks Comm. Planning Comm. DATE: 04/17/23 COMMITTEE CHAIR: TOSH SHARP RECOMMENDATIONS: SPONSOR/ADMIN. Public Works Department COMMITTEE Unanimous Approval; Forward to Committee of the Whole COST IMPACT / FUND SOURCE EXPENDITURE REQUIRED AMOUNT BUDGETED APPROPRIATION REQUIRED $ $9,350,000 $ Fund Source: Comments: MTG. DATE RECORD OF COUNCIL ACTION 04/24/23 MTG. DATE ATTACHMENTS 04/24/23 Informational Memorandum dated 04/14 Reservoir Siting Overview PPT CIP Pg. 56 Minutes from Transportation and Infrastruture Services Committee meeting of 04/17/23 COUNCIL AGENDA SYNOPSIS ----------------------------------Initials --------------------------------- ITEM NO. Meeting Date Prepared by Mayor’s review Council review 04/24/23 GL 4.C. 103 104 Attachments: Reservoir Siting PPT; CIP pg. 56 INFORMATIONAL MEMORANDUM TO: Transportation Infrastructure Committee FROM: Hari Ponnekanti, Public Works Director/City Engineer BY: Adib Altallal, Utilities Engineer CC: Mayor Allan Ekberg DATE: April 14, 2023 SUBJECT: Water Fund – Water Reservoir Sites Update Project No. 91240102 Information Only ISSUE Update on potential Water Reservoir sites. BACKGROUND During the City of Tukwila’s 2015 Water Comprehensive Plan, the consultant identified that the continued growth within the City no longer meets the Department of Health’s water storage requirements. As a result, the Water Reservoir and Pump Station was included in the Capital Improvement Program. During the most recent Water Comprehensive Plan update, the City’s water storage deficiencies were highlighted again. Further development throughout the City and especially in the Ryan Hill and Tukwila South areas are likely to be hindered or completely halted due to these water storage deficiencies. During subsequent January 2021 communications with the Transportation and Infrastructure Services Committee, four potential sites were identified. Two of those sites were in the Ryan Hill neighborhood and the other two in the North Hill neighborhood. Both of those neighborhoods have high topography that would reduce pumping costs. A new reservoir will need to be constructed regardless. ANALYSIS By constructing a second reservoir, the City would meet the Department of Health’s water storage requirements. During the January 2021 update, a viable site in the Ryan Hill area was for sale and the plan was to construct the reservoir there and connect the neighborhood to the rest of the water system so everyone in the city benefits. That site, however, is no longer available. During the December 2021 update, a willing seller in the North Hill neighborhood was found. After further investigations, it was determined the prevalence of wetlands made the site a poor candidate. Since finding land that meets the City’s criteria has been a difficult endeavor, the prospect of finding two distinct suitable sites appears not to be viable. In the Summer of 2022, the site of the old Fire Station 52 was identified as a city-owned viable option. The construction of a new reservoir at this site would save the City’s General Fund money by taking over the responsibilities of the demolition and mitigation of the old fire station 52 building. The project would greatly improve the condition of Hazelnut Park by expanding the area and adding recreational items for the residents’ use. Further, the project would retain the old City Hall building and could potentially help improve that building as well. That will be sufficient if the Ryan Hill neighborhood is connected to the rest of the water system. The proposed site at the former Fire Station 52 would enable Ryan Hill to be connected via a pump station as opposed to a different reservoir entirely. The Committee of the Whole is scheduled to receive a briefing on the project at its April 24, 2023, meeting. FISCAL IMPACT The adopted 2023 Capital Improvement Program identified an estimated project budget of $16 million for the Water Reservoir and corresponding pump station. There would likely be increased staffing needs to operate and maintain the new reservoir as well. RECOMMENDATION Information only. Staff are looking for Council direction on next steps. 105 106 OVERVIEW | MARCH 2023 Reservoir Siting Conceptual Study 14475 59th Avenue S 1 0 7 CAROLLO | 2 01 Site Description 1 0 8 CAROLLO |3 Site Location Site 1 0 9 CAROLLO |4 Existing Improvements •Hazelnut Park to remain/improve •Tukwila Heritage and Cultural Center to remain •Vacated fire station to be demolished and its site mitigated. 1 1 0 CAROLLO |5 Site Characteristics •Generally flat; ±10’ grade change •Primarily impervious •Some trees •Improved frontages with curb, gutter and sidewalk •Water, sewer, storm, gas and power available 1 1 1 CAROLLO |6 Environmental Considerations •Mapped Class 2 (Moderate) and Class 3 (High) Landslide Areas onsite •Likely to encounter groundwater »Shoring and dewatering will be significant portion of reservoir cost •Protect/Replace Trees »“Protection of trees shall be a major factor in the location, design, construction and maintenance of streets and utilities.” 1 1 2 CAROLLO |7 Nearby Water Infrastructure •Large diameter existing pipes surrounding the site »Most surrounding mains may not need to be upsized •Alternate location near existing reservoir was modeled last year »Recommend site-specific modeling 1 1 3 CAROLLO |8 02 Land Use 1 1 4 CAROLLO |9 Zoning •Low Density Residential (LDR) •“Water Pump Station” & “Water Utility Reservoir and Related Facilities” are Unclassified Uses within LDR •Requires Unclassified Use Permit TMC 18.10.060 1 1 5 CAROLLO | 10 03 Conceptual Layout 1 1 6 CAROLLO |11 Reservoir Site •Assumed boundary at south limits of Hazelnut Park •Park and Heritage Center to remain Heritage Center Hazelnut Park 1 1 7 CAROLLO |12 Reservoir Site •Required yards for LDR zone based on assumed front (S 147th St), side, and rear •Rear setback from assumed subdivision line 1 1 8 CAROLLO |13 Reservoir Site •Approximate minimum buildable area with required yards »Alternate layouts possible with reconfiguring of Hazelnut Park space •Minimum parking (including ADA accessible parking or access) required for park and/or Heritage center? •Restrictions on parcel due to park classification/funding? 1 1 9 CAROLLO |14 Site Layout •2.5 MG reservoir desired •Conceptual footprint determined with assumed buildable area »Circular: 112’ diameter, 34’ height »Rectangular: 100’ square, 33.5’ height »(Does not account for wall thickness or interior supports) •40’ x 50’ footprint for pump station 1 2 0 CAROLLO |15 Example Reservoir(Partially Below Grade) •2.5 MG prestressed, partially buried concrete tank •112’ diameter, 28’ height •Alpine, CA 1 2 1 CAROLLO |16 Example Reservoir(Fully Below Grade) •Crestview Park, Tukwila »Highline Water District reservoir (7.6 MG) •Seward Park, Seattle »Seattle Public Utilities CSO storage facility (2.65 MG) 1 2 2 CAROLLO |17 04 Key Assumptions & Considerations 1 2 3 CAROLLO |18 Key Assumptions & Limitations Hydraulic suitability Buildable area Survey Site grading Geotechnical & shoring Hazelnut Park and Heritage Center restrictions Onsite stormwater facilities Classified Use Permit 1 2 4 5656 125 126 City of Tukwila City Council Transportation & Infrastructure Services Committee Meeting Minutes April 17, 2023 5:30 p.m. – Hybrid Meeting; Duwamish Conference Room & MS Teams Councilmembers Present: Tosh Sharp, Chair; Kate Kruller, Mohamed Abdi Staff Present: David Cline, Hari Ponnekanti, Adib Altallal, Seong Kim, Griffin Lerner, Cyndy Knighton, Sherry Edquid Chair Sharp called the meeting to order at 5:30 p.m. I.BUSINESS AGENDA A.Contract: 2023 Annual Small Drainage Program Staff is seeking Council approval of a contract with KPG Psomas Inc. in the amount of $99,785.00 for design and permitting services for the 2023 Small Drainage Program. Committee Recommendation Unanimous approval. Forward to May 1, 2023 Regular Consent Agenda. B.Purchase Agreement: Large Water Meter Replacement Staff is seeking Council approval of an agreement to purchase two Sensus Large Water Meters from Ferguson Waterworks in the amount of $73,652.58 as part of the Large Water meter Replacement Project. Committee Recommendation Unanimous approval. Forward to May 1, 2023 Regular Consent Agenda. C.Water Reservoir Site Proposal Staff briefed the Committee on a proposal to construct a second water reservoir at the site of the former Fire Station 52. Item(s) for follow-up: •Determine if old City Hall/Historical Society building is on the national historic register. •Provide additional detail on deed restriction on the site Committee Recommendation Forward to April 24, 2023 Regular Consent Agenda. Miscellaneous The meeting adjourned at 6:48 p.m. TS Committee Chair Approval Minutes by LH 127