NECANICUM RIVER WATERSHED ASSESSMENT Final Report March, 2002 A Report by: E&S Environmental Chemistry, Inc. P.O. Box 609 Corvallis, OR 97339 Kai U. Snyder Timothy J. Sullivan Richard B. Raymond Erin Gilbert Deian Moore Necanicum River Watershed Assessment March, 2002 Page ii TABLE OF CONTENTS LIST OF FIGURES........................................................... vi LIST OF TABLES........................................................... viii LIST OF ACRONYMS .........................................................x ACKNOWLEDGMENTS ..................................................... xii EXECUTIVE SUMMARY.................................................... xiii CHAPTER 1. INTRODUCTION .............................................. 1-1 1.1 Purpose and Scope ................................................... 1-1 1.1.1 The Decision Making Framework ................................. 1-1 1.1.2 Geographic Information Systems Data Used in this Assessment .......... 1-2 1.1.3 Data Confidence ............................................... 1-6 1.2 Setting ............................................................. 1-8 1.3 Ecoregions ........................................................ 1-11 1.4 Population ......................................................... 1-13 1.5 Climate and Topography.............................................. 1-14 1.6 Geology........................................................... 1-16 1.7 Vegetation......................................................... 1-16 1.7.1 Potential Natural Vegetation ............................... 1-16 1.7.2 Historic Floodplain Vegetation ................................... 1-18 1.7.3 Current Vegetation ............................................ 1-18 1.7.4 Large Conifers ............................................... 1-20 1.7.5 Open Areas .................................................. 1-21 1.8 Land Use.......................................................... 1-22 1.9 Channel Habitat Types............................................... 1-23 CHAPTER 2. FISHERIES................................................... 2-1 2.1 Introduction ......................................................... 2-1 2.2 Fish Presence ....................................................... 2-2 2.3 Species of Concern................................................... 2-3 2.4 Coho .............................................................. 2-5 2.4.1 Life History ................................................... 2-5 2.4.2 Listing Status ................................................. 2-5 2.4.3 Population Status .............................................. 2-5 2.4.4 Factors Responsible for Decline ................................... 2-7 2.4.5 Species Distribution ........................................... 2-10 2.4.6 Hatcheries ................................................... 2-10 2.5 Coastal Cutthroat ................................................... 2-12 2.5.1 Life History .................................................. 2-12 2.5.2 Listing Status ................................................ 2-12 2.5.3 Population Status ............................................. 2-13 2.5.4 Factors Responsible for Decline .................................. 2-13 Necanicum River Watershed Assessment March, 2002 Page iii 2.5.5 Species Distribution ........................................... 2-14 2.5.6 Species Interactions ........................................... 2-15 2.5.7 Hatcheries ................................................... 2-15 2.6 Chum............................................................. 2-16 2.6.1 Life History .................................................. 2-16 2.6.2 Listing Status ................................................ 2-16 2.6.3 Population Status ............................................. 2-16 2.6.4 Factors Responsible for Decline .................................. 2-17 2.6.5 Species Distribution ........................................... 2-18 2.6.6 Hatcheries ................................................... 2-18 2.7 Steelhead.......................................................... 2-18 2.7.1 Life History .................................................. 2-18 2.7.2 Listing Status ................................................ 2-20 2.7.3 Population Status ............................................. 2-20 2.7.4 Factors Responsible for Decline .................................. 2-22 2.7.5 Species Distribution ........................................... 2-23 2.7.6 Hatcheries ................................................... 2-23 2.8. Chinook ........................................................... 2-24 2.8.1. Life History .................................................. 2-24 2.8.2 Listing Status ................................................ 2-25 2.8.3 Population Status ............................................. 2-25 2.8.4 Factors Responsible for Decline .................................. 2-25 2.8.5 Species Distribution ........................................... 2-26 2.8.6 Hatcheries ................................................... 2-26 2.9 Pacific Lamprey .................................................... 2-27 2.9.1 Life History .................................................. 2-27 2.9.2 Listing Status ................................................ 2-28 2.9.3 Population Status ............................................. 2-28 2.9.4 Factors Responsible for Decline .................................. 2-28 2.9.5 Species Distribution ........................................... 2-28 CHAPTER 3. AQUATIC AND RIPARIAN HABITATS ........................... 3-1 3.1 Introduction ......................................................... 3-1 3.2 Aquatic Habitat Data ................................................. 3-3 3.2.1 Stream Morphology and Substrates ................................ 3-3 3.2.2 Large Woody Debris ............................................ 3-5 3.2.3 Shade ........................................................ 3-7 3.3 Riparian Conditions .................................................. 3-7 3.3.1 Large Woody Debris Recruitment Potential ......................... 3-11 3.3.2 Stream Shading ............................................... 3-12 3.4 Fish Passage Barriers ................................................ 3-15 3.4.1 Natural Barriers ............................................... 3-15 3.4.2 Culverts ..................................................... 3-17 3.5 Channel Modifications............................................... 3-19 3.6 Wetlands.......................................................... 3-20 3.6.1 National Wetlands Inventory .................................... 3-21 3.6.2 Wetland Extent and Types ...................................... 3-22 3.6.3 Wetlands and Salmonids ........................................ 3-24 Necanicum River Watershed Assessment March, 2002 Page iv 3.6.4 Filling and Diking of Wetlands .................................. 3-27 3.7 Conclusions........................................................ 3-27 CHAPTER 4. HYDROLOGY ................................................ 4-1 4.1 Introduction .................................. 4-1 4.2 Hydrologic Characterization............................................ 4-2 4.2.1 Watershed and Peak Flow Characterization .......................... 4-2 4.2.2 Stream Flow .................................................. 4-3 4.3 Potential Land Use Impacts on Peak Flows................................ 4-4 4.3.1 Forestry ...................................................... 4-5 4.3.2 Agriculture and Rangeland ...................................... 4-6 4.3.3 Forest and Rural Roads .......................................... 4-6 4.3.4 Urban and Rural Residential Areas ................................ 4-7 4.3.5 Other Potential Hydrologic Impacts ................................ 4-8 4.4 Conclusions......................................................... 4-9 CHAPTER 5. WATER USE ................................................. 5-1 5.1 In-stream Water Rights................................................ 5-2 5.2 Consumptive Water Use............................................... 5-3 5.2.1 Irrigation ..................................................... 5-3 5.2.2 Municipal and Domestic Water Supply ............................. 5-3 5.3 Non-Consumptive Water Use........................................... 5-5 5.4 Water Availability .................................................... 5-5 5.5 Conclusions......................................................... 5-6 CHAPTER 6. SEDIMENT SOURCES......................................... 6-1 6.1 Introduction ......................................................... 6-1 6.2 Screening for Potential Sediment Sources ................................. 6-2 6.3 Slope Instability ..................................................... 6-2 6.4 Road Instability ...................................................... 6-5 6.5 Road Runoff ........................................................ 6-7 6.6 Streambank Erosion .................................................. 6-9 6.7 Conclusions......................................................... 6-9 CHAPTER 7. WATER QUALITY ............................................ 7-1 7.1 Introduction ......................................................... 7-1 7.1.1 Assessment Overview ........................................... 7-1 7.1.2 Components of Water Quality .................................... 7-1 7.2 Beneficial Uses.....................................................