DRAFT SKAGIT Shoreline Master Shoreline Analysis Report for Shorelines in COUNTY Program Skagit County and the Towns of Hamilton UPDATE and Lyman Prepared for: Skagit County Town of Lyman Town of Hamilton Grant No. 1100205 September 1 2011 DRAFT SKAGIT COUNTY GRANT NO.1100205 S H O R E L I N E A N A L Y S I S R EPORT for Shorelines in Skagit County and the Towns of Hamilton and Lyman Prepared for: Town of Lyman Skagit County PO Box 1248 Planning and Development Lyman, WA 98263 Services 1800 Continental Place Town of Hamilton Mount Vernon, WA. 98273 PO Box 528 Hamilton, WA 98255 Prepared by: August, 2011 This report was funded in part through a grant from the Washington Department of Ecology. The Watershed Company Reference Number: 090207 The Watershed Company Contact Person: Dan Nickel Printed on 30% recycled paper. Cite this document as: The Watershed Company. August 2011. DRAFT Shoreline Analysis Report for Shorelines in Skagit County and the Towns of Lyman and Hamilton. Prepared for the Skagit County Planning and Development Services Department, Mount Vernon, WA. TA B L E O F C ONTENTS Page # 1 Introduction ............................................................................... 1 1.1 Background and Purpose ............................................................................. 1 1.2 Shoreline Jurisdiction ................................................................................... 2 1.3 Study Area ...................................................................................................... 3 1.3.1 Skagit County ................................................................................................... 3 1.3.2 Town of Lyman ................................................................................................ 4 1.3.3 Town of Hamilton............................................................................................. 4 2 Summary of Current Regulatory Framework .......................... 5 2.1 Shoreline Management Act ........................................................................... 5 2.2 Skagit County ................................................................................................. 5 2.3 Towns of Lyman and Hamilton ..................................................................... 7 2.4 State Agencies and Regulations ................................................................... 7 2.5 Federal Regulations ....................................................................................... 9 3 Summary of County Ecosystem Conditions ......................... 12 3.1 Geographic and Ecosystem Context .......................................................... 12 3.2 Historic Geology, Topography, and Drainage Patterns ............................ 15 3.3 Major Land Use Changes and Current Shoreline Condition ..................... 18 4 Shoreline Inventory ................................................................. 25 4.1 Introduction .................................................................................................. 25 4.2 Inventory Data Summary, Assumptions, Limitations, and Data Gaps ..... 27 4.2.1 Management Unit Determination ................................................................. 28 4.2.2 Land Use Patterns ......................................................................................... 28 4.2.3 Current Land Use........................................................................................... 30 4.2.4 Future Land Use ............................................................................................ 33 4.2.5 Existing Skagit County Shoreline Master Program Designations ............ 35 4.2.6 Transportation ............................................................................................... 36 4.2.7 Utilities ............................................................................................................ 37 4.2.8 Impervious Surfaces ..................................................................................... 38 4.2.9 Vegetation ...................................................................................................... 38 4.2.10 Shoreline Modifications ................................................................................ 38 i 4.2.11 Existing and Potential Public Access ......................................................... 39 4.2.12 Geologically Hazardous Areas ..................................................................... 41 4.2.13 Frequently Flooded Areas ............................................................................ 41 4.2.14 Wetlands ......................................................................................................... 41 4.2.15 Fish and Wildlife Habitat Conservation Areas ............................................ 42 4.2.16 Critical Aquifer Recharge Areas .................................................................. 42 4.2.17 Historical or Archaeological Sites ............................................................... 42 4.2.18 Water Quality .................................................................................................. 43 4.3 Management Unit Conditions...................................................................... 44 4.3.1 Management Unit 1- Samish River............................................................... 55 4.3.2 Management Unit 2- Samish Island, Padilla Bay, and East Side of Swinomish Channel ..................................................................................... 58 4.3.3 Management Unit 3- Swinomish Tribal Reservation .................................. 62 4.3.4 Management Unit 4- Fidalgo Island and Other Islands.............................. 65 4.3.5 Management Unit 5- Skagit Bay/Delta ......................................................... 71 4.3.6 Management Unit 6- Lower Skagit Diking Districts ................................... 74 4.3.7 Management Unit 7- Samish River............................................................... 79 4.3.8 Management Unit 8- Middle Skagit River .................................................... 82 4.3.9 Management Unit 9- Upper Skagit River ..................................................... 86 4.3.10 Management Unit 10- Nooksack Watershed ............................................... 93 4.3.11 Management Unit 11- Stillaguamish Watershed ........................................ 95 5 Reach-scale Functions and Processes ................................. 98 5.1 Functional Evaluation Approach, Rationale and Limitations ................... 98 5.1.1 Reach Delineation.......................................................................................... 98 5.1.2 Functions and Impairments ........................................................................ 100 5.1.3 Limitations .................................................................................................... 106 5.2 Management Unit Functional Evaluation ................................................. 107 5.2.1 Samish Bay .................................................................................................. 107 5.2.2 Samish Island, Padilla Bay, and East Side of Swinomish Channel ........ 108 5.2.3 Swinomish Tribal Reservation ................................................................... 111 5.2.4 Fidalgo Island and Other Islands ............................................................... 115 5.2.5 Skagit Bay/Delta........................................................................................... 121 5.2.6 Lower Skagit- Diking Districts .................................................................... 127 5.2.7 Samish River ................................................................................................ 131 5.2.8 Middle Skagit ................................................................................................ 135 5.2.9 Upper Skagit (WRIA 4) ................................................................................ 141 5.2.10 Nooksack (WRIA 1) ...................................................................................... 157 5.2.11 Stillaguamish (WRIA 5) ............................................................................... 160 6 Land Use Analysis and Implications ................................... 164 ii 6.1 Shoreline Land Capacity Analysis ............................................................ 164 6.1.1 Land Capacity Analysis .............................................................................. 164 6.1.2 Potential Use Conflicts ............................................................................... 169 6.1.3 Samish Bay .................................................................................................. 169 6.1.4 Samish Island, Padilla Bay, and East Side of Swinomish Channel ........ 170 6.1.5 Swinomish Tribal Reservation ................................................................... 171 6.1.6 Fidalgo Island and Other Islands ............................................................... 172 6.1.7 Skagit Bay/Delta........................................................................................... 173 6.1.8 Lower Skagit Diking District ....................................................................... 173 6.1.9 Samish River ................................................................................................ 174 6.1.10 Middle Skagit ................................................................................................ 175 6.1.11 Upper Skagit