Urban Stream Restoration Practices: An Initial Assessment Final Report Kenneth Brown Center for Watershed Protection 8391 Main Street Ellicott City, MD 21043 For: The U.S. Environmental Protection Agency Office of Wetlands, Oceans, and Watersheds and Region V October, 2000 URBAN STREAM RESTORATION PRACTICES Acknowledgments This assessment was made possible through a grant from the United States Environmental Protection Agency. The project team would like to extend our gratitude to Don Brady with the U.S. EPA, Office of Wetlands, Oceans, and Watersheds and Tom Davenport with U.S. EPA, Region V, for their support of this project. The project team would like to extend our appreciation to the many individuals who contributed information, time and resources to make this project possible. Specifically, the project team would like to acknowledge Dave Knorr of Environmental Systems Analysis, Chin Lin of the Baltimore County Department of Environmental Resources and Management, Shane Brooks of the University of Maryland, Todd Jeneski of the City of Rockville, Tom Price of the Northeastern Illinois Planning Commission, Don Roseboom of the Illinois State Water Survey, Susan Jacobs and Robert Shreeve of the Maryland State Highway Administration, Steve Nelson of the Carrol County Bureau of Planning, John Galli of the Washington Metropolitan Council of Governments, Tim Schueler of Environmental Quality Resources, and Charles Hegburg of KCI, Inc. The author would also like to thank the staff of the Center for Watershed Protection for their help in collecting field data, with special thanks to Heather Holland for her help in preparing this document: Donna Boring Ted Brown Deb Caraco Rich Claytor Karen Cappiella Hye Yeong Kwon Tom Schueler Paul Sturm Laura Thomson Rebecca Winer Alex Yeboah Jennifer Zielinski 1 URBAN STREAM RESTORATION PRACTICES 2 URBAN STREAM RESTORATION PRACTICES Table of Contents Executive Summary ..................................................................................................................... 9 1.0 Introduction .................................................................................................................... 11 1.1 Limitations of the Assessment ...................................................................................................................... 11 1.2 Report Organization ....................................................................................................................................... 12 2.0 Background ..................................................................................................................... 13 2.1 The Effects of Urbanization on Stream Channels .......................................................................................... 13 2.2 Past Management of Urban Streams .............................................................................................................. 15 3.0 Study Design ................................................................................................................... 17 3.1 Project Selection ........................................................................................................................................... 17 3.1.1 Project Selection Criteria ................................................................................................................. 17 3.1.2 Final Project Selection ..................................................................................................................... 18 3.2 Assessment Methodology ........................................................................................................................... 18 3.2.1 Stream Restoration Practice Design Groups ........................................................................................ 18 3.2.2 Assessment Protocol and Rationale .................................................................................................... 23 3.2.3 Data Assessment ................................................................................................................................ 26 4.0 Results and Discussion .................................................................................................. 27 4.1 Bank Protection Practices ............................................................................................................................ 27 4.1.1 Rootwad Revetments .......................................................................................................................... 31 4.1.2 Imbricated Rip-Rap .............................................................................................................................. 32 4.1.3 Boulder Revetments ............................................................................................................................ 35 4.1.4 Lunkers ................................................................................................................................................ 37 4.1.5 A-Jacks ................................................................................................................................................ 39 4.2 Grade Control Practices ............................................................................................................................... 40 4.2.1 Rock Vortex Weirs ................................................................................................................................42 4.2.2 Rock Cross Vane .................................................................................................................................. 43 4.2.3 Rock Weirs .......................................................................................................................................... 44 4.2.4 Step Pools ........................................................................................................................................... 44 4.2.5 Log Drops and V-Log Drops ............................................................................................................... 47 4.3 Flow Deflection/Concentration Practices .................................................................................................... 49 4.3.1 Wing Deflectors - Single and Double .................................................................................................. 49 4.3.2 Log Vanes ............................................................................................................................................ 52 4.3.3 Rock Vanes - Straight Vanes and J-vanes............................................................................................ 52 4.3.4 Cut-off Sills .......................................................................................................................................... 54 4.3.5 Linear Deflectors ................................................................................................................................. 54 4.4 Bank Stabilization Practices ......................................................................................................................... 56 4.4.1 Coir Fiber Logs .................................................................................................................................... 56 4.4.2 Live Fascines ....................................................................................................................................... 58 4.4.3 Brush Mattresses ................................................................................................................................ 61 4.4.4 Bank Regrading and Vegetative Stabilization ...................................................................................... 61 5.0 Recommendations .......................................................................................................... 64 5.1 Bank Protection Practice Recommendations ............................................................................................... 64 5.1.1 Rootwad Revetment Recommendations .............................................................................................. 65 5.1.2 Imbricated Rip-rap Recommendations ................................................................................................. 66 5.1.3 Boulder Revetments Recommendations .............................................................................................. 67 5.1.4 Lunker Recommendations ................................................................................................................... 69 5.1.5 A-jacks Recommendations .................................................................................................................. 69 5.2 Grade Control Practice Recommendations ................................................................................................... 69 5.2.1 Rock Vortex Weir Recommendations ................................................................................................... 70 5.2.2 Rock Cross Vane Recommendations ................................................................................................... 70 3 URBAN STREAM RESTORATION PRACTICES 5.2.3 Rock Weir Recommendations .............................................................................................................. 73 5.2.4 Step Pool Recommendations ............................................................................................................... 73 5.2.5 Log Drop and V-Log Drop