Draft City of Lacey 2016 Stormwater Design Manual Note: Some pages in this document have been purposely skipped or blank pages inserted so that this document will copy correctly when duplexed. City of Lacey 2016 Stormwater Design Manual DRAFT July 12, 2016 CITY OF LACEY 2016 STORMWATER DESIGN MANUAL Acknowledgments LACEY CITY MANAGER Scott Spence LACEY CITY COUNCIL LACEY PLANNING COMMISSION Andy Ryder, Mayor Mike Beehler, Chair Cynthia Pratt, Deputy Mayor Carolyn Cox, Vice Chair Virgil Clarkson Mark Morgan Jeff Gadman Carolyn St. Claire Lenny Greenstein Catherine Murcia Jason Hearn Paul Enns Michael Steadman Michael Goff Sharon Kophs City of Lacey External Stakeholders Group SDM Advisory Committee Technical Subcommittee Scott Egger, Public Works Director Joshua Deal, Olympia Master Builders Rick Walk, Community Devel. Director Sharon Kophs, Lacey Planning Comm. Doug Christenson, SDM Project Manager Steve Hatton, Hatton Godat Pantier Samra Seymour, Associate Planner Bob Holcomb, KPFF Roger Schoessel, City Engineer Calvin McCaughan, Landau Associates Tom Stiles, Development Review Mgr. Consultants Peter Brooks, Water Resources Mgr. Craig Doberstein, CPD Solutions Julie Rector, Water Quality Analyst Anneliese Sytsma, Herrera Environmental Tim Reisher, Street Maintenance Mgr. Consultants, Inc. Ryan Andrews, Planning Manager Matt Fontaine, Herrera Environmental Wade Duffy, Building Official Consultants, Inc. Martin Hoppe, Transportation Mgr. Rick McBroom, Stormwater Technician Prepared By City of Lacey Department of Public Works Water Resources Division July 2016 Primary References Washington Department of Ecology, Stormwater Management Manual for Western Washington, August 2012 Pierce County, Stormwater Management and Site Development Manual, 2015 Low Impact Development Technical Guidance Manual for Puget Sound, 2012 July 2016 Chapter 1 – Introduction i CITY OF LACEY 2016 STORMWATER DESIGN MANUAL Table of Contents Chapter 1 – Introduction ............................................................................................... 1-1 1.1 Background and Authority .......................................................................................... 1-1 1.2 Objective ..................................................................................................................... 1-2 1.3 Organization of this Manual ........................................................................................ 1-3 1.3.1 Overview of Manual Content ....................................................................... 1-3 1.3.2 Organization of this Manual ......................................................................... 1-4 1.4 Site Planning and Layout ............................................................................................ 1-4 1.5 Development of BMPs for Stormwater Management ................................................. 1-6 1.5.1 Best Management Practices .......................................................................... 1-6 1.5.2 Construction Stormwater BMPs (Chapter 5) ................................................ 1-6 1.5.3 Flow Control BMPs (Chapter 7) ................................................................... 1-6 1.5.4 Low Impact Development BMPs (Chapter 7) .............................................. 1-7 1.5.5 Runoff Treatment BMPs (Chapter 8) ........................................................... 1-7 1.5.6 Source Control BMPs (Chapter 9) ................................................................ 1-7 1.6 Maintenance of Stormwater Best Management Practices ........................................... 1-7 1.7 Relationship of this Manual to Federal, State, and Local Regulatory Requirements ............................................................................................................... 1-8 1.7.1 The Manual’s Role as Technical Guidance and Requirements .................... 1-8 1.7.2 More Stringent Measures ............................................................................ 1-10 1.7.3 Retrofitting .................................................................................................. 1-10 1.7.4 Presumptive Versus Demonstrative Approaches to Protecting Water Quality ........................................................................................................ 1-10 1.7.5 Phase II – NPDES and State Waste Discharge Stormwater Permits for Municipalities ............................................................................................. 1-11 1.7.6 Industrial Stormwater General Permit ........................................................ 1-11 1.7.7 Construction Stormwater General Permit ................................................... 1-12 1.7.8 Endangered Species Act ............................................................................. 1-12 1.7.9 Section 401 Water Quality Certifications (included in JARPA) ................ 1-13 1.7.10 Hydraulic Project Approvals (included in JARPA) .................................... 1-13 1.7.11 Aquatic Lands Use Authorizations (included in JARPA) .......................... 1-14 1.7.12 Requirements Identified Through Watershed or Basin Planning ............... 1-14 1.7.13 Underground Injection Control – UIC Authorizations ............................... 1-14 Glossary and Abbreviations ............................................................................. Glossary-1 Glossary .................................................................................................................. Glossary-1 Abbreviations .......................................................................................................... Glossary-39 July 2016 Chapter 1 – Introduction iii CITY OF LACEY 2016 STORMWATER DESIGN MANUAL Chapter 1 – Introduction 1.1 Background and Authority The City of Lacey 2016 Stormwater Design Manual (SDM) is a completely revised and updated replacement for the 2010 SDM. The 2016 SDM is based on the 2012 edition of the Washington State Department of Ecology Stormwater Management Manual for Western Washington (Ecology Manual, as amended December 2014). In creating the 2016 SDM, the City of Lacey Department of Public Works has edited and reorganized Ecology’s Manual for ease of use and local application. The reader is referred to the Ecology Manual for further background information and supporting details, if desired. The Manual is available on Ecology’s web site at: <www.ecy.wa.gov/programs/wq/stormwater/manual.html>. The City of Lacey is required to regulate stormwater discharges to the municipal stormwater system and to waters of the state, in compliance with the Western Washington Phase II National Pollutant Discharge Elimination System (NPDES) Municipal Stormwater Permit (the Permit). Under the Permit, the city must establish and apply the minimum requirements specified in the Permit and provide design guidance for stormwater quality and quantity control for new development and redevelopment projects in Lacey. Through this manual, the city is complying with the Clean Water Act and the NPDES Municipal Stormwater Permit. Where requirements in this manual are also covered in any other law, ordinance, resolution, rule, or regulation of any kind the more restrictive law shall govern. This manual has been adopted by local ordinance and has force of law. Failure to comply may trigger administrative or enforcement action, and result in project delays, fines, or penalties. For the purposes of interpreting and using this manual, the words “shall,” “will,” and “must” are always mandatory; the word “should” is situation-specific and not mandatory but strongly encouraged; and “may” is situation-specific and permissive. The City of Lacey Stormwater Design Manual Administrator (SDM Administrator) is authorized to determine if situation-specific requirements are applicable to any particular project. The city’s SDM Administrator is also authorized to request information or to impose requirements beyond those specified in this manual, which may occur for various reasons including but not limited to: • To protect public safety, health, and welfare • To prevent flooding, erosion, endangerment to property, habitat destruction, or water quality degradation • To implement regulatory mandates such as a Total Maximum Daily Load (TMDL) July 2016 Chapter 1 – Introduction 1-1 CITY OF LACEY 2016 STORMWATER DESIGN MANUAL • To protect uninterruptible services • To implement increases in requirements imposed by state or federal agencies or other pertinent factors • To clarify, correct, augment, or update information in this manual 1.2 Objective The objective of this manual is to provide guidance and requirements to control the quantity and quality of stormwater produced by new development and redevelopment, such that they comply with water quality standards and contribute to the protection of beneficial uses of the receiving waters. Water quality standards include: • Chapter 173-200 of the Washington Administrative Code (WAC), Water Quality Standards for Groundwaters of the State of Washington • Chapter 173-201A WAC, Water Quality Standards for Surface Waters of the State of Washington • Chapter 173-204 WAC, Sediment Management Standards This manual establishes the minimum “Core Requirements” for stormwater control and site development requirements for all new development and redevelopment in the city and applies to all sites as detailed in Chapter 2 – Core Requirements for New Development and Redevelopment, and Chapter 3 – Stormwater Submittals. The core requirements outlined