PROTECTION OF MARINE RIPARIAN FUNCTIONS IN PUGET SOUND, WASHINGTON Prepared for: Washington Department of Fish and Wildlife (WDFW Agreement 08-1185) Prepared by: Washington Sea Grant 3716 Brooklyn Avenue NE Seattle, WA 98105 (UW Contract: A39268) Jim Brennan, Project Manager, Washington Sea Grant Hilary Culverwell, Starrfish Consulting Rachel Gregg, Washington Sea Grant Pete Granger, P.I., Washington Sea Grant June 15, 2009 1 Table of Contents Section I. Introduction .................................................................................................................... 1 Section II. Approach/Methods ........................................................................................................ 3 Section III. Overview: Riparian Areas and Riparian Buffers ......................................................... 6 Riparian areas .............................................................................................................................6 Riparian buffers ...........................................................................................................................6 Why are marine riparian areas important? .................................................................................6 Section IV. Riparian Functions ....................................................................................................... 7 1. Water quality ............................................................................................................................7 a. Technical overview: riparian influence on water quality function ..................................... 7 c. Conclusions and Recommendations for water quality ...................................................... 10 2. Fine Sediment Control ...........................................................................................................11 a. Technical overview: riparian influence on fine sediment control function ...................... 11 b. Key findings from buffer literature and science panel ...................................................... 12 c. Conclusions and Recommendations for sediment ............................................................ 14 3. Shade/Microclimate ...............................................................................................................14 a. Technical overview: riparian vegetation influence on shade function .............................. 14 b. Key findings from buffer literature and science panel ...................................................... 15 c. Conclusions and Recommendations ................................................................................. 16 4. Large Woody Debris ..............................................................................................................17 a. Technical overview: riparian influence on large woody debris function .......................... 17 b. Key findings from buffer literature and science panel ...................................................... 18 c. Conclusion and Recommendations ................................................................................... 21 5. Litter Fall/Organic Matter ......................................................................................................21 a. Technical overview, riparian influence on litter fall/input of organic matter ................... 21 b. Key findings from buffer literature and science panel ...................................................... 22 c. Conclusion and Recommendations for litter fall/organic matter inputs ........................... 24 6. Hydrology/Slope Stability .....................................................................................................24 a. Technical overview: riparian influence on hydrology/slope stability function ................ 24 b. Key findings from buffer literature and science panel ...................................................... 25 c. Conclusion and Recommendations ................................................................................... 28 7. Fish and Wildlife Habitat .......................................................................................................28 a. Technical overview, riparian influence on wildlife function ............................................ 28 b. Key findings from buffer literature and science panel ...................................................... 29 c. Conclusion and Recommendations ................................................................................... 29 Section V. Impacts to Marine Riparian Functions ....................................................................... 30 1. Introduction ............................................................................................................................30 2. Development ..........................................................................................................................31 a. Water quality ..................................................................................................................... 31 b. Fine sediment control ........................................................................................................ 31 c. Shade/microclimate ........................................................................................................... 32 d. Large Woody Debris (LWD) ............................................................................................ 32 e. Litter fall/organic matter inputs ........................................................................................ 32 f. Wildlife .............................................................................................................................. 33 e. Hydrology/Slope Stability ................................................................................................. 33 2 3. Agriculture .............................................................................................................................33 a. Water Quality .................................................................................................................... 34 b. Fine sediment control ........................................................................................................ 34 c. Shade/Microclimate .......................................................................................................... 34 d. Large Woody Debris ......................................................................................................... 34 e. Litter fall/organic matter inputs ........................................................................................ 35 f. Hydrology/slope stability .................................................................................................. 35 g. Wildlife ............................................................................................................................. 35 4. Forest Practices ......................................................................................................................35 a. Water Quality .................................................................................................................... 35 b. Shade/Microclimate .......................................................................................................... 36 c. Large Woody Debris ......................................................................................................... 36 e. Fine sediment control ........................................................................................................ 36 f. Wildlife .............................................................................................................................. 37 g. Hydrology/Slope stability ................................................................................................. 37 5. Other Impacts of Concern ......................................................................................................37 Section VI. General Conclusions and Management Recommendations for Protecting Marine Riparian Function.......................................................................................................................... 38 1. General Conclusions Adapted Solely from the NRC (2002) .................................................38 2. Overarching Recommendations .............................................................................................38 3. Recommendations to Avoid or Minimize Specific Impacts ..................................................39 Literature Cited ........................................................................................................................... 41 Literature Consulted but Not Cited in Text ............................................................................... 52 APPENDIX A. Researchers who conducted technical and scientific literature review on riparian buffers and functions..................................................................................................................... 71 APPENDIX B. Brief descriptions of seven buffer review documents ......................................... 72 APPENDIX C. Literature cited for seven buffer functions .......................................................... 73 APPENDIX D. Original FEMAT curves...................................................................................... 92 APPENDIX E: Literature summary documenting the impacts of development, agriculture and forest practices