This page intentionally left blank. TABLE OF CONTENTS Acknowledgments................................................................................................... A-1 Executive Summary ................................................................................................ ES-1 Overview............................................................................................................................ES-1 Approach ...........................................................................................................................ES-1 Stormwater Quality BMP Implementation Guidelines .............................................................ES-3 Recommendations And Conclusions .....................................................................................ES-4 Chapter 1 Introduction............................................................................................ 1-1 Purpose And Goals .............................................................................................................. 1-2 Goal 1: Develop A Framework And Shared Vision For Meeting Denver·s Stormwater Quality Requirements And Goals................................................................ 1-2 Goal 2: Develop BMP Strategies That Work In Various Denver Settings .............................. 1-3 Goal 3: Develop A Common Foundation For Interdepartmental Understanding Of Stormwater Quality Requirements And Their Role In The Planning Process ................. 1-4 Goal 4: Develop Framework And Priorities For Future Work Needed To Meet Goals .......... 1-4 Approach ............................................................................................................................ 1-4 Principles And Policies .......................................................................................................... 1-7 Opportunities And Challenges .............................................................................................. 1-9 Address Water Quality Issues............................................................................................ 1-9 Improve Interdepartmental Cooperation With Regard To Water Quality .............................. 1-9 Coordinate Compatible Uses Between Parks And Water Quality Facilities ......................... 1-10 Enhance Compatibility Between Urban Design Goals And Water Quality Facilities............. 1-10 Implement Effective, Sustainable, Attractive, Multi-Purpose, Safe, And Well-Designed Bmps 1-11 Ensure Long-Term BMP Operation And Maintenance....................................................... 1-11 Develop Financing And Institutional Strategies For Regional Bmps .................................... 1-11 Scope Limitations ............................................................................................................... 1-12 Plan Overview.................................................................................................................... 1-13 Chapter 2 Overview Of Major Denver Drainage Basins And Potential Urban Stormwater Impacts............................................................................. 2-1 Overview Of Denver Drainage Basins.................................................................................... 2-1 South Platte River............................................................................................................. 2-7 First Creek....................................................................................................................... 2-7 Second Creek.................................................................................................................. 2-8 Third Creek ..................................................................................................................... 2-8 Box Elder Creek............................................................................................................... 2-9 Irondale Gulch ................................................................................................................ 2-9 Clear Creek .................................................................................................................... 2-9 Sand Creek ................................................................................................................... 2-10 Westerly Creek .............................................................................................................. 2-10 Cherry Creek................................................................................................................. 2-11 Goldsmith Gulch........................................................................................................... 2-11 Sloan·s Lake.................................................................................................................. 2-12 Lakewood Gulch ........................................................................................................... 2-12 Dry Gulch ..................................................................................................................... 2-12 Weir Gulch ................................................................................................................... 2-12 Sanderson Gulch........................................................................................................... 2-13 Table of Contents Page TOC-1 Table of Contents West Harvard Gulch ...................................................................................................... 2-13 Harvard Gulch .............................................................................................................. 2-14 Bear Creek.................................................................................................................... 2-14 Marston Lake North (Tributary Of Bear Creek)................................................................. 2-15 Overview Of Lakes............................................................................................................. 2-15 Characterization Of Denver Lake And Stream Conditions...................................................... 2-18 Overview Of The Effects Of Urbanization On Receiving Waters............................................. 2-20 Adverse Physical Impacts Of Urban Runoff ...................................................................... 2-22 Chemical Characteristics Of Urban Runoff ...................................................................... 2-24 Summary ........................................................................................................................... 2-30 Chapter 3 Regulatory Drivers ................................................................................... 3-1 Phase I Stormwater CDPS Permit ........................................................................................... 3-1 Denver International Airport (DIA) CDPS Permit ...................................................................... 3-5 EPA·s April 2004 Audit Of Denver·s Stormwater Management Program ................................... 3-6 Denver·s Stormwater Quality Related Policies ......................................................................... 3-6 Other Denver Ordinances, Rules And Regulations ................................................................ 3-10 Colorado Water Quality Control Act And Regulations........................................................... 3-11 Total Maximum Daily Loads (Tmdls) .................................................................................... 3-14 Regional Efforts And Agreements ......................................................................................... 3-17 Denver Regional Council Of Governments/Clean Water Plan .......................................... 3-17 Joint Stormwater Task Force ........................................................................................... 3-17 South Platte Cooperative For Urban River Evaluation (CURE)............................................ 3-18 Cherry Creek Stewardship Partners ................................................................................. 3-21 Barr Lake/Milton Reservoir Watershed Association ........................................................... 3-21 Selenium Stakeholders Group ........................................................................................ 3-22 Other Federal And State Regulations ................................................................................... 3-22 Current And Future Compliance Implications Of Evolving Regulations ................................... 3-24 Section 309 Report And Potential Aquatic Life Classification Changes............................... 3-25 Possible Stream Standard Changes Under Consideration For July 2005............................ 3-26 Source Water Protection................................................................................................. 3-27 Nutrient Criteria............................................................................................................. 3-27 Sediment Deposition...................................................................................................... 3-29 Pollutant Trading ........................................................................................................... 3-29 Summary ........................................................................................................................... 3-29 Chapter 4 Related Documents.................................................................................