Fundamentals of Urban Runoff Management TechNICAL AND INstItutIONAL Issues 2nd Edition | 2007 Earl Shaver Richard Horner Joseph Skupien Chris May Graeme Ridley Fundamentals of Urban Runoff Management: Technical and Institutional Issues 2nd Edition, 2007 By: Earl Shaver Richard Horner Joseph Skupien Chris May Graeme Ridley Editing and layout by Nadene Rehnby Produced in cooperation with the U.S. Environmental Protection Agency Fundamentals of Urban Runoff Management is available under limited copyright protection. You may download, distribute, photocopy, cite or excerpt this document provided it is properly and fully credited and not used for commercial purposes. The permission of the North American Lake Management Society is required for all other uses. Acknowledgement The North American Lake Management Society (NALMS) support for this effort is most appreciated. NALMS’ mission is to forge partnerships among citizens, scientists, and professionals to foster the management and protection of lakes and reservoirs for today and tomorrow. Lakes and reservoirs are used more now than ever and water pollution is a key problem in maintenance of lake health. NALMS supports the development, communication, and use of excellent science and cutting-edge management to further lake protection goals. We hope this manual will provide information that can be used to further NALMS’ goals. North American Lake Management Society PO Box 5443 4513 Vernon Blvd, Suite 103 Madison, WI 53703-0443 Phone (608) 233-2836 Fax (608) 233-3186 [email protected] www.nalms.org Contents PREFACE ...................................................................................................................................................8 CHAPTER 1: INTRODuctION .......................................................................................................................9 Discussion ............................................................................................................................................. 10 Shifting Program Emphasis .................................................................................................... 10 Phase II Storm Water Rule ....................................................................................................... 11 Increased Emphasis on the TMDL Approach ........................................................................ 11 Changing Hydrologic Approaches ...........................................................................................12 Better Water Quality Data .........................................................................................................12 Increased Prominence of Biomonitoring and Biocriteria .....................................................12 Improved and New Practices ...................................................................................................12 Where From Here ......................................................................................................................13 Concluding Thoughts .............................................................................................................................14 References .............................................................................................................................................14 CHAPTER 2: WATER QUANTITY ImpActs OF URBAN LAND USE ...............................................................15 Reality vs. Theory ..................................................................................................................................17 The Rainfall-Runoff Process ................................................................................................................ 20 Runoff Estimation: Typical Parameters ...............................................................................................21 Rainfall .......................................................................................................................................21 Time ........................................................................................................................................... 28 Drainage Area ...........................................................................................................................30 Soils ........................................................................................................................................... 31 Land Cover ................................................................................................................................ 34 Runoff Estimation: Methods and Models ........................................................................................... 36 Runoff Volume Methods .......................................................................................................... 36 Peak Runoff Rate Methods ...................................................................................................... 36 Runoff Hydrograph Methods .................................................................................................. 36 Impacts of Land Use Change ............................................................................................................... 38 Summary and Conclusions ..................................................................................................................41 References .............................................................................................................................................41 CHAPTER 3: WATER QUALITY ImpActs OF URBANIZATION .......................................................................43 Background ........................................................................................................................................... 45 Stormwater Pollutant Sources ................................................................................................ 45 Stormwater Runoff Pollutants ................................................................................................46 Pollutant Fate and Transport .................................................................................................. 51 Quantifying Urban Runoff Pollutants ................................................................................................. 52 Urban Runoff Measurement ................................................................................................... 52 Urban Runoff Patterns ............................................................................................................. 53 Urban Runoff Pollution Characteristics ................................................................................. 54 Urban Wetland Water Quality: Puget Sound Case Study ................................................................... 59 Estimating Urban Runoff Pollutant Loading ...................................................................................... 63 Unit-Area Loading .................................................................................................................... 63 Simple Empirical Method ........................................................................................................ 64 Computer-Based Models ......................................................................................................... 66 References ............................................................................................................................................ 68 CHAPTER 4: BIO-phYSICAL ImpActs OF URBANIZATION ON AquATIC ECOSYstems ................................73 Background ............................................................................................................................................74 Hydrologic Impacts .............................................................................................................................. 76 Landscape Alteration ............................................................................................................... 76 Urban Hydrologic Regime .......................................................................................................80 Biological and Ecological Effects of Urban Hydrologic Change ........................................... 83 Urban Freshwater Wetland Hydrology .................................................................................. 86 Physical Impacts .................................................................................................................................. 87 Geomorphic Changes .............................................................................................................. 87 Degradation of Riparian Integrity ........................................................................................... 89 Effects of Urbanization on Stream Habitat and Biota .......................................................... 92 Ecological Impacts of Urban Stormwater Runoff Quality .................................................................98 Background...............................................................................................................................98 Stormwater Toxicity in Freshwater .......................................................................................100 Stormwater Toxicity in Estuarine-Nearshore Areas ........................................................... 102 Impacts of Contaminated Aquatic Sediment on Benthic Organisms ..............................