KILCHIS WATERSHED ANALYSIS TILLAMOOK BAY NATIONAL ESTUARY PROJECT Editors: Bruce Follansbee, Ph.D., Senior Scientist Ann Stark, M.S., GIS Coordinator Contributors: Tom Ascher, Tillamook County Planner, STAC Co-Chair Bruce Apple, Tillamook County Watershed Council Coordinator Mary Barczak, Resource Planner, Nestucca Watershed Council Keith Braun, ODFW Bob Ellis, Ellis Ecological Services Lisa Heigh, TBNEP Roxanna Hinzman, TBNEP Rick Klumph, ODFW Antonius Laenen, USGS Keith Mills, Geotechnical Specialist, ODF Steve Nelson, Director, TBNEP Bob Pedersen, Resource Conservationist, NRCS George Robison, Hydrologist, ODF Dana Shuford, BLM Randy Stinson, Hydrologist, SWCD Bob Teran, ODF October 1998 This document was completed under Cooperative Agreement CE990292-1 with the U.S. Environmental Protection Agency Printed on recycled paper ii TABLE OF CONTENTS List of Figures.......................................................................................................................vi List of Tables.......................................................................................................................viii EXECUTIVE SUMMARY ..................................................................................................ix 1.0 The Setting: Characteristics and Land Use in the Tillamook Basin......................................1 Introduction...............................................................................................................1 Regional Setting .........................................................................................................3 Land Ownership and Human Uses of the Kilchis Watershed .......................................8 Environmental Problems Related to Human Uses ......................................................16 2.0 Hydrologic Characterization...........................................................................................21 Introduction.............................................................................................................21 Climate....................................................................................................................21 Streamflows.............................................................................................................24 Land and Water Interface.........................................................................................25 3.0 Stream Channel..............................................................................................................27 Introduction.............................................................................................................27 General Characteristics of Stream Channels ..............................................................27 Channel Complexity Due To Large Woody Debris Content ......................................30 Channel Complexity Due To Boulder Content...........................................................35 Debris Flows and Stream Channel Scouring..............................................................36 Stream Channel Bank Erosion..................................................................................37 Gravel Removal.......................................................................................................40 Stream Channel Widening ........................................................................................43 Instream Enhancement Sites .....................................................................................45 4.0 Riparian.........................................................................................................................47 Introduction.............................................................................................................47 Degraded Riparian Stands........................................................................................47 Riparian Shade Evaluation........................................................................................50 Kilchis Mainstem......................................................................................................52 Riparian Large Woody Debris Supply Potential........................................................53 Location of Current Riparian Enhancement Projects..................................................54 Potential Riparian Restoration Sites...........................................................................56 iii 5.0 Erosion..........................................................................................................................57 Introduction.............................................................................................................57 Erosion Setting and Landslides on Forest Lands........................................................57 Erosion Timing, Sediment Size, and Delivery to Streams............................................59 Erosion Volume Estimate..........................................................................................60 Erosion Background Levels......................................................................................61 Shallow, Rapid Landslide Risk .................................................................................62 Deep Seated Landslides...........................................................................................63 Erosion of Fine Sediment from Roads.......................................................................64 Erosion on Abandoned Roads..................................................................................66 Sediment Reduction Efforts ......................................................................................67 6.0 Water Quality................................................................................................................69 Introduction.............................................................................................................69 Water Temperature Exceeding Salmonid Habitat Requirements.................................69 Water Contaminants Other Than Bacteria.................................................................78 Bacterial Contamination of Surface Waters...............................................................78 Location of Residences on Private Septic Systems ....................................................79 7.0 Wetlands .......................................................................................................................81 Introduction.............................................................................................................81 Conversion of Wetlands to Other Uses.....................................................................81 National Wetland Inventory .....................................................................................85 Hydrologic Isolation of Wetlands..............................................................................85 8.0 Estuary..........................................................................................................................87 Introduction.............................................................................................................87 Status of Estuary Fish...............................................................................................87 Status of Native Shellfish..........................................................................................91 Status of Oysters......................................................................................................93 Status of Shrimp.......................................................................................................94 Status of Dungeness Crabs.......................................................................................95 Status of Mammal Species .......................................................................................96 Estuary Habitat ........................................................................................................97 Estuary Bathymetry................................................................................................100 The Status of Eelgrass............................................................................................103 Human Physical Alterations of the Estuary...............................................................108 iv 9.0 Fish and Wildlife ..........................................................................................................113 Introduction...........................................................................................................113 Salmonid Populations ............................................................................................113 Salmon Critical Habitat Areas.................................................................................128 Habitat Needed For Salmonid Life Stages..............................................................133 Channel Modifications Affecting Habitat .................................................................138 Features Blocking Fish Passage..............................................................................140 Critical Lowland Areas Needing Protection and Restoration ...................................143 Unscreened Water Diversions ................................................................................143 Endangered Plant and Animal Species ....................................................................145 Wildlife Species Residing