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HomeMy WebLinkAboutCDN 2019-01-29 Item 2C - Flood Control - Lower Green River Corridor Plan / Flood Hazard Management PlanAllan Ekberg, Mayor Public Works Department- Henry Has , Director INFOR ATIONAL E ORANDU TO: Community Development and Neighborhoods Committee FROM: Henry Hash, Public Works Directoru BY: Ryan Larson, Senior Program Manager CC: Mayor Ekberg DATE: January 25, 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 alternatives 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 concerns 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 Information Only. ATTACHMENTS Draft Puget Sound Salmon Recovery Council Letter Lower Green River Corridor — Flood Hazard Management Plan Information. ZACouncil Agenda Items \Public Works Lower Green Corridor Plan\Info Memo Corridor Plan.docx 105 106 King County Flood Control District ATTN: Michelle Clark, SEPAResponsible Official Sl6Third Avenue Room l2OO 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. Afundamental 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 inthe survival nfChinook salmon. |tisabsolutely critical toincrease the rearing habitat of the Lower Green River to recover the Green River Chinook salmon population --and recovery ofChinook salmon Puget Sound'wide. Continued decline in the Green River Chinook salmon population is of regional and statewide concern as itsrecoveryisessentia|tode'|istingPuQetSoUnd[hinookasThreatenedond,moreover,avoid|osin8the Southern Resident killer whale population. The three alternatives identified in the November 26, 2018 Draft Programmatic Environmental Impact Statement (DPE|S) scalping 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 SEPAenvironmental 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. 107 108 KING � � �~���}~4� � �_.�_/K~�NTY /��� /�/��� 8�8�»�/»_/8_/ «.�»�/l�MOL D I S T R l C T Project Description The Lower Green River iasusceptible toflooding and flood damage tha1.effeotspeople and residential, commercial, industrial, and agricultural properties along its banks. The potential impacts and damages ofmajor 0oodingon paop|e, structures, infrastructure, buuineoaeu, and jobs throughout the Lower Green River Valley are substantial. Tbaddress these issues, the hJngCounty Flood Control District is preparing uLower Green River Corridor Flood Hazard Management Plan (Plan) for approximately 21 river miles nfthe Lower Green River that flow through the cities ofAuburn, Kent, Renton, Tukwila, and unincorporated King County. The goal ofthe Plan iatoprovide along -term approach toreduce flood risk and improve fish habitat vvhi|o supporting the economic prosperity ofthe region. See the Study Area map onpage 2. Programmatic Environmental Impact Statement The District isalso preparing aPrognammaUn Environmental Impact Statement (PBS).which will analyze alternatives for flood protection that could be included inthe Plan. The PB8describes potential environmental impacts and measures \oreduce or eliminate them. Because each alternative includes a variety offlood protection projects thatmnakeup a ''pnognonn^ of actions, a PBS in being prepared. The PBSvviU evaluate the potential impacts ofthe projects identified in each alternative. What are the Alternatives? The "No Action Alternative" iarequired 1oobjectively evaluate and compare the other two alternatives. |t vvnu|d include completing existing projects adopted inthe 2O18-23Capital Improvement Program (Reoo|utionRCD2O18'062). ��=The "XYndeneboGaogo�,hhnfx�mtof/ncmaaodLevel �~"offrntoutionA1ten/ative"vvou|dino|udeOnni|oa ofnew levees and improvements to17miles of existing levees. ��"Tho "Greater Geugm�/h/tExtent mi�m Increased Level —"Proteotion, integrated Habitat and Recreation, Agricultural Protection Facilities, and Habitat Restoration Project Partnerships Alternative" isthe same aoAlternative 2 with the addition of1Omiles ufnew levees and 2miles ufnon-structural improvements. Incentives to provide habitat restoration could also boprovided. Each ofthe alternatives includes continued maintenance nfexisting flood facilities. Alternatives 2and 3would also include some drainage improvements toagricultural lands and flood -proofing ofagricultural structures. More detailed descriptions ofthe alternatives can bofound online at: xvvvvx|oxvargnennaopo.onJ. Process The PB8will take about two years to complete. Comment periods during scoping and during review of the Draft PBSwill provide opportunities for the public toprovide input. VER k � E511 'It " 109 s ERAL Lower Green River Corridor Flood Hazard Management Plan and Programmatic Environmental Impact Statement Study Area Study Area • 3o River Mile �. Green River l City Area The scoping comment period is from November 28, 2018, to January 29, 2019. Provide your comments in -person: Sc©ping Meeting 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. ©pen 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 inferprete de espaiiol disponible en la reunion. If you 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 vvww.Iowergreensepa.org or by calling 206-263-0602. This document has been provided in English and Spanish. Este documento se facilifo en ingles y en espaiol. If you require a translation in a different language, please call 206-775-8778. �34 0 1 2 Miles � i l September 2018 KING COUNTY FLOOD CONTROL DI SIR ICI The used Tie kiteis thin map is su*ct ,ha tons and amuaa land at wuw.tri avycareserviaagsSkys eansotusa.aspc Your access and use is cmlYxM co your acceptance cd Anse torts and c nanny Caw K v Coyly GIS F. 101:6_4Ziduynon_c2f_._ 110 KING COUNTY Lower Gree fiver FLOOD CONTROL DISTRICT Corridor Scoping Meeting GRPE 01 IRO 45, A 1V Ac tar Aberna ivesi In1,[oybdio litres * vyp* At•liiii4 6 Type Sf aIltyl° 5 •'I Type G iieilib 0.8 l\bsAclon Aferr atb re d any Ty•e,D lac Pt lire e xeative No Action ' Auburn Exhibit 1 Lower Green River Corridor Plan Alternative Framework Draft 101012018 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 �rrl Type D: Physical non-structural Existing Conditions and Facilities: ,., 2018.2023 Capital Improvement Program (CIP) Construction F-'• PL 84-99 Levee Systems (approx. 17 miles) Other Levees and Revetments (approx. 11 miles) Existing Private Levee Shoreline with No Facilities (approx. 14 miles) Green River Mainstem (42 shoreline miles) `C7 , River Miles (RM) Cities Note: The PL 84-99 levees have an existing LOP' of 12,000 cfs plus variable freeboard. A 0 0.5 r 2 uno ` 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. am fee '�t J a Sh, a pied C11$ 202$ GD avi -b32)R (nol(dn l itedth S)MF ital ')a sh e Mw(de if1c( as°e)h)(tb vk I aP fPfl top y proxl(taf,2 IhitrnkV fadl(Itiey w(IliS 4 100 year•Ley ( of P1o;8otloP (8,8ga etslplug 3 ontin146 maipkdifpfNr nP e>�s irl9 l pit$ s"of;, (Three alternatives are being studied) 111 KI\G COUNTY Lower Green Rave FLOOD CONTROL DISTR. ICT Corridor Scoping eeting ALernatve 2 Moderate Geographic Extent of Increased Level of Protection Alternative 2includes,construction of oHo lengths of new or improved tactiliies " 'r Type A facility 1017 mites (50Y Type B facility: A 68 miles (23%j • Ype C facility 5,41 miles (27%) 1 e° Alternative 2 would not include anv Type D projects except where needed to Maintaik current level of protection Kent King County cntrol Distil 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 2,510 1 or less; footprint of 100 feet or less Type B: Somewhat flatter stable riverward embankment . f 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 reen River Mainslem (42 shoreline miles) River Miles (RM) Cities Note: The PL 84-99 levees have an existing LOP* of 12,000 cfs plus variable freeboard. U e 5,5 2 A 5500s * 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 typo 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. (F CjPs",nply�t a spin 14 Aotlorl,; curYettly 4jnfttdeit d of�e isti l e an areve(rne! (Three alternatives are being studied) 112 KING COUNTY Lower Green River FLOOD CONTROL DISTRICT Corridor Scoping Meeting FLOOD�AZARD MAU4GEMEFfl1PLANATIC ENVIRONIVIE A naive 3 Greater Geographic Extent with Increased Level of Protection, Integrated Habitat and Recreation, Agricultural Protection Facilities, and Habitat Restoration Project Partnerships '16'llernativo Includ engths of new or irser?0°Pstructi°11 of fa • TYPe A facility: 15 43 miles‘I 'ed • Type B faciitty, 5.39 , miles (I7i>s) • Type c facUity • 88 nilleS P996) Type 1 91 miles (65,6) 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 3freeboard Flood Facility Type: Type A: Most constrained, riverward embankment side ; slope of 2.5 to 1 or less; footprint 01100 feet or less Type 8: 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) 1.0 River Miles (RM) IL.711 Cities Note: The PL 84-99 levees have an existing LOP* of 12,000 cfs plus variable freeboard. N 0 0.5 2 Wes A • Level of Protection (LOP) is defined as the amount billow 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. 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(Three alternatives are being studied) 113 KING COUNTY FLOOD CONTROL moz�* mm nxomw Lower Green River Corridor Flood Hazard Management Plan Programmatic Environmental Impact Statement ScopiDg Comment Form Submit acomment onthe PE8byfilling out this form and leaving itinthe comment box attoday's meeting orbymailing ittothe following address byJanuary 29,2Q1!: King County Flood Control District Attn: Michelle Clark, SEPAResponsible Official S16Third Avenue Room22OO Seattle, VVAQ82O4 YoucanaboemaUcommentstnLnxverGreen5EpA@oWngcountY.gov orsubmit them online at Nome: Email Address; Comment: (please feel free to use the back of this form if you need more space) 114 KING COUNTY FLOOD CONTROL DISTRICT 510 Third Avrimr.1Zoon) 1201). Sermle, IVA 08101- 206.226.1020 inlbili:kingeotint11006:0111101.,mg Ivwsv.kingeounqiloodroult.01.nm 115 116 8/30/2018 Flood Facility Project Type A • Riverward side slope < 2.5:1 • Footprint 100' or less 15TYPICAL OH OHVV= ordinary high water Exposed Flood Wall 3TYPAL Typical Levee '1044,,":Mtp,w' tiyamlow " *M. Typical Floodwall Not to Scale Illustrative Only 8/30/2018 Flood Facility Project Type B • Riverward side slope >2.5:1 • Footprint 100'-150' OHW Green River OHW= ordinary high water OHW Graett River 15" —Exposed Flood Wal AS ACCESS VARIES, TYPICALLY 100 - 120' ..A-xxxlieetor- Typical Floodwall IC 16' - 20' -ex TYPICAL 2,72=0,1 15ACCESS JJ Typical Levee VARIES, TYPICALLY 120' - 1507 Not to Scale Illustrative Only 4/23/2018 Flood Facility Project Type C Riverward side slope 3:1 Footprint 150' or more SETBACK LEVEE 150'4. OHW= ordinary high water Typical Levee Not to Scale Illustrative Only 4/23/2018 Flood Facility Project Type D • Physical Non -Structural :V OHW Green Riwr Example of farm pad and drainage provemen OHW Green River OHW= ordinary high water d 01- Up to 3' f+e* c.14 testimm...* 160 (other potential measures include wet flood proofing, berms or ring levees) Not to Scale Illustrative Only