WHITE PAPER Marine and Estuarine Shoreline Modification Issues Submitted to Washington Department of Fish and Wildlife Washington Department of Ecology Washington Department of Transportation April 2001 WHITE PAPER Marine and Estuarine Shoreline Modification Issues Submitted to Washington Department of Fish and Wildlife Washington Department of Ecology Washington Department of Transportation Prepared by Gregory D. Williams and Ronald M. Thom Battelle Marine Sciences Laboratory Pacific Northwest National Laboratory 1529 West Sequim Bay Road Sequim, WA 98382 Telephone: 360/ 681-3655 April 17, 2001 Note: Some pages in this document have been purposefully skipped or blank pages inserted so that this document will copy correctly when duplexed. Marine and Estuarine Shoreline Modification Issues LEGAL NOTICE This report was prepared by Battelle Memorial Institute (Battelle) as an account of sponsored research activities. 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The views and opinions of authors expressed herein do not necessarily state or reflect those of Battelle. wp1 /00-01215-009 white paper shoreline modification.doc April 17, 2001 i Marine and Estuarine Shoreline Modification Issues Table of Contents Overview of Aquatic Habitat Guidelines Project..........................................................................vii Introduction ..................................................................................................................................... 1 Assessment of the State of Knowledge........................................................................................... 3 Methods.................................................................................................................................... 3 Overview of Ecological and Habitat Issues .................................................................................... 5 Definition of Estuarine and Nearshore Marine Habitats.......................................................... 5 Estuarine and Nearshore Marine Habitat Descriptions and Functions .................................... 6 Definition and Overview of Shoreline Modifications and Restoration ................................... 9 Estuarine and Marine Nearshore Habitat Use By Living Resources ............................................ 11 Salmonids............................................................................................................................... 11 Forage Fish............................................................................................................................. 14 Groundfish ............................................................................................................................. 15 Nearshore Food Webs............................................................................................................ 17 Conceptual Framework for Assessing Impacts............................................................................. 19 Impact Types and Controlling Factors................................................................................... 19 Habitat Controlling Factors, Structure, and Function............................................................ 21 Habitats and Resource Linkages............................................................................................ 22 Effects of Shoreline Modification................................................................................................. 25 Energy Dissipating Structures: Breakwaters and Jetties........................................................ 25 Construction and Operation Techniques ...................................................................... 25 Direct Studies of Biological Impacts............................................................................ 26 Physical Effects of Structure ........................................................................................ 28 Shoreline Stabilization Methods ............................................................................................ 30 Hard Approaches: Bulkheads, Revetments, Seawalls, Groins, Ramps ................................. 31 Construction and Operation Techniques ...................................................................... 31 Direct Studies of Biological Impacts............................................................................ 35 Physical Effects of Structure ........................................................................................ 37 Soft Approaches: Beach Nourishment and Biotechnical Measures....................................... 42 Construction and Operation Techniques ...................................................................... 42 Direct Studies of Biological Impacts............................................................................ 44 Physical Effects of Structure ........................................................................................ 45 Other Structures Affecting Hydrology: Tide Gates, Outfalls, and Artificial Reefs............... 46 Construction and Operation Techniques ...................................................................... 46 Outfalls.................................................................................................................. 47 Artificial Reefs ...................................................................................................... 47 Physical Effects of Structure ........................................................................................ 49 Tide gates .............................................................................................................. 49 Outfalls.................................................................................................................. 50 wp1 /00-01215-009 white paper shoreline modification.doc April 17, 2001 iii Marine and Estuarine Shoreline Modification Issues Artificial Reefs ...................................................................................................... 51 Direct Studies of Biological Impacts............................................................................ 52 Tide Gates ............................................................................................................. 52 Outfalls.................................................................................................................. 53 Artificial Reefs ...................................................................................................... 54 Cumulative Effects of Shoreline Modification ...................................................................... 54 Definition...................................................................................................................... 54 Examples ...................................................................................................................... 55 Scenario for Puget Sound ............................................................................................. 56 Habitat Protection and Mitigation Techniques.............................................................................. 59 Structural Alternatives ........................................................................................................... 59 Non-Structural Management Alternatives ............................................................................. 61 Estuary Restoration................................................................................................................ 62 Background .................................................................................................................. 62 Restoration in Washington State .................................................................................. 63 Direct Studies ............................................................................................................... 65 General Restoration Projects Results .................................................................... 65 Eelgrass ................................................................................................................. 67 Physical Short and Long-term Effects.......................................................................... 69 Site Subsidence ..................................................................................................... 70 Erosion/Deposition................................................................................................ 71 Predation and Herbivory ....................................................................................... 71 Undesirable Species .............................................................................................. 71 Other Lessons.......................................................................................................