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HomeMy WebLinkAboutUtilities 2016-02-23 Item 2B - Update - NPDES Program: Low Impact Development CodeCity of Tukwila Allan Ekberg, Mayor INFORMATIONAL MEMORANDUM TO: Mayor Ekberg Utilities Committee FROM: Bob Giberson, P.E., Public Works Director 46'9 BY: Greg Villanueva, NPDES Coordinator DATE: February 19, 2016 SUBJECT: NPDES Program Project No. 99341210 Low Impact Development (LID) Code Update ISSUE LID code presentation and update. BACKGROUND The City's National Pollutant Discharge Elimination System (NPDES) Phase II permit requires that the City review, revise, and make effective their local development - related codes, rules, standards, or other enforceable documents to incorporate and require LID principles and LID Best Management Practices no later than December 31, 2016. ANALYSIS The City contracted with Otak, Inc. to perform an LID gap analysis and assist the City with LID implementation. Otak will provide a 15 minute presentation on LID and gap analysis progress to date. This presentation will inform Council members of the new LID rules required for the Tukwila Municipal Code. FINANCIAL IMPACT The LID Gap Analysis consultant agreement was approved in December 2015 for $59,006, of which $50,000 is funded by a Department of Ecology's Water Quality Stormwater Capacity Grant. INFORMATION ONLY Information only. C:\ Users \susan\AppData \Local1Microsofl \Windows \Temporary Internet Files \Content.Outlook \360AGYOJ \Info Memo Otak LID Codes 02 -19 -16 gl.docx City of Tukwila LID Code Update Presentation to City Council Utilities Committee February 23, 2016 Goals for Tonight Discuss a process to update Tukwila's development and stormwater codes to remove barriers to Low Impact Development (LID), reduce stormwater runoff through the use of LID site planning practices, and require LID facilities. • What is LID? • Why are we doing this? 7, • How will we achieve it? • What is next? What is LID? 0) What is LID? Low Impact Development is a set of site development principals to minimize impervious surfaces, maintain native vegetation, and manage stormwater runoff close to its source. Examples • Skinny Streets • Parking Area Reduction • Clustering • LID BMPs Sea Street LID, Seattle, WA. Photo courtesy of Washington State Department of Ecology What is LID? v Parking Area Reduction & Stormwater Management Parking lots and roof tops are largest contributors of impervious surface coverage in commercial areas (Schueler, 1995), and a parking lot can require up to 400 sf per vehicle (i.e. 1 acre / 100 cars) (CHI, 2000). Image from Strongtowns.org Image from Inland Paving Asphalt Co, Tri- Cities, WA Image from Elected Official Briefing, by AHBL and Department of Ecology What is LID? co LID Best Management Practices (BMPs) The King County Surface Water Design Manual will require LID BMPs such as Bioretention, Permeable Pavements, Dispersion, and Downspout Infiltration on almost all development sites. Residential trees cistern driveway with grass center 7 mpoat- emended soli ita.r. IT„,..krolrtm",_ 1 Road� llllr►ll►llll 'l l I i i l 1 l 1 l t 6W`,IV Commerc`i:P Photo courtesy LocalEcologist.org rain garden overflow Graphic courtesy City of Seattle Regulatory Framework National Pollutant Discharge Elimination System (NPDES) Municipal Stormwater Permit • Clean Water Act • Washington Department of Ecology • 2013 — 2018 Permit Cycle • Permit Requirement S5.C.4 Revise Development & Stormwater Codes to Require LID • Minimize Impervious Surfaces • Minimize Loss of Native Vegetation • Minimize Stormwater Runoff • Make LID the Common Approach to Site Development Integrating LID into Local Codes: .)und Psrrnersnrp evaporation Hydrology Before / After Traditional Development O 4 4 4 6 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 6 6 4 6 6 The Natural W ter Cycle 4 4 4 4 4 4 4 4 4 4 4 4 4 n 4 a 4 s 4 4 4 4 4 4 4 less e, ego- Ira nepiraiion eriroorrtibn reduce water table bedroc groundwater 1=3 The Urban Water Cycle Images from Integrating LID into Local Codes, by AHBL and Puget Sound Partnership • Stream discharges increase rapidly and recede quickly • Higher flow velocities = greater erosion and pollutant transport • Peak flow event frequency increases • Groundwater recharge reduced Goal of LID • Urban Landscape More Like Pre - Development Hydrology Example (Less Runoff) Replicating Natural Hydrologic Processes To Manage Stormwater Upland ta,n gatdeos infiltrate ttam rater dwng small storTS $t nw,,fter.,atilt Ma sedunent catchment and Ilan Speeade, w the- yeti meadow LID Integrated Into Redevelopment Trail on Vault LID T ltrrapMl floodptan roto.n el orate, goatty Ireatnsertt Ihmughfittraton Losing (in Stream Net and 1713.eyfry tuinuttramngatte y Infiltration stream Upland Meadow Ftoodptain Wetland tHandwomans eCom (Beim and rprCMKI$Stttho to itUOdytyn teettphd Trait/ Boardwalk d iii AIL i ilk iiiiiiIli INFILTRATION CHAMBERS © you are Here TPA. NSI TIO r• Z U NE.. STREAM BUFFER M+Uer Creek 0 STREAM Design for Miller Creek, Burien NERA, Otak, Inc. M • Streets • Safety & Convenience • Attractive Places Community Needs City Standards • Street Widths • Parking • Landscaping • Drainage / Stormwater Control ) • Street Network • Parking Lots • Clearing & Grading • Stormwater Facilities Developer Actions City Development Codes / Standards Guide: • Creation of impervious surfaces • Removal or retention of native vegetation • Location of development • How /where stormwater is managed Completed andscapes • Buildings • Pavement • Vegetation • Stormwater Where to look • Title 11: ROW Use • Title 14: Water and Sewers • Title 17: Subdivisions • Title 18: Zoning • Infrastructure Design and Construction Standards • Comprehensive Plan Image from Elected Official Briefing, by AHBL and Department of Ecology Topics • Site Planning and Assessment • Healthy Soils • Landscaping and Vegetation • Hard and Impervious Surfaces • Bulk and Dimensions • Clearing and Grading • Streets and Roads • Parking • Design Guidelines and Standards • Stormwater Management and Maintenance • Subdivision and Planned Unit Development • Critical Areas and Shoreline Management ■htya 4va,atatsa\\t Site Ar.,,ai`y k Image from Integrating LID into Local Codes, by AHBL and Puget Sound Partnership Update City Codes and Standards 28 Ft Stmt �x�- '+tea r� lbv �kw _. Parking on both sides la - UAW • +130• -•ter 24 Ft Street Parking on one side 7Y x7 s + +,y'e frappe s. . "99 Ilfreurrij.q. -- -� Burien 2008 Road Design and Construction Standards Conventional r-� LID I t`:; ., ,.,.:77..„..s.i.y-- Vegetation/ 9i Retention Images by AHBL For example: Standard Streets and Planned Unit Developments Outcomes • Reduce Impervious Surfaces • Encourage Retention of Native Vegetation • Manage Stormwater Close to the Source • Permit Compliance 0) Image by Otak, Inc. Outcomes Library (By Others) Porous Concrete Permeable Pavers (Vehicular) Existing Tree To Re Permeable Pavers (Pedestrian) Concrete Proposed Pedestrian Lights (Typ.) Proposed StreetTrees (Typ.) c Concrete 1 "= 30'•0" Section A -A Section B -B Section C -C August 20th, 2012 TUKWILA 1 VILLAGE South 144th Street Streetscape Enhancements Ltmthe LAstudio City Staff Participants Public Works • Project Management • Road Standards • Use of Right of Way • Engineering Community Development • Site Planning • Parking • Subdivisions • Landscaping Fire Marshal • Street Widths • Landscaping Attorney • Authority • Legal Review Consultant • Code Review • Drafts Ecology requires participation from city officials responsible for setting and enforcing development codes. op What is Next? Roadmap 1. Assemble Project Team 2. Review Existing Codes and Standards (Gap Analysis) 3. Understand General LID Topics 4. Amend Existing Codes and Develop New Codes to Fill Gaps 5. Public Review and Adoption Process ( Final Adoption ) 6. Ensure Successful Implementation Deadline December 31, 2016 c0 We are here October 2016 Questions? otak iGb a 'ar ner