Burnt Bridge Creek Watershed Fecal Coliform Bacteria, Temperature, Dissolved Oxygen, and pH Source Assessment Report October 2020 Publication 20-03-016 Publication Information This report is available on the Department of Ecology’s website at: https://fortress.wa.gov/ecy/publications/SummaryPages/2003016.html. Data for this project are available in Ecology’s EIM Database. Study ID: STEB0002. The Activity Tracker Code for this study is 19-001. Suggested Citation McCarthy, S. 2020. Burnt Bridge Creek Watershed Fecal Coliform Bacteria, Temperature, Dissolved Oxygen, and pH: Source Assessment. Publication 20-03-016. Washington State Department of Ecology, Olympia. https://fortress.wa.gov/ecy/publications/SummaryPages/2003016.html. Water Resource Inventory Area (WRIA) and 8-digit Hydrologic Unit Code (HUC) numbers for the study area: WRIA 28, HUC number 17080003. Contact Information Publications Coordinator Environmental Assessment Program Washington State Department of Ecology P.O. Box 47600 Olympia, WA 98504-7600 Phone: 360-407-6764 Washington State Department of Ecology – https://ecology.wa.gov • Headquarters, Olympia 360-407-6000 • Northwest Regional Office, Bellevue 425-649-7000 • Southwest Regional Office, Olympia 360-407-6300 • Central Regional Office, Union Gap 509-575-2490 • Eastern Regional Office, Spokane 509-329-3400 COVER PHOTO: Burnt Bridge Creek near sampling site BBC04.3 from 2008–2009 fieldwork. Any use of product or firm names in this publication is for descriptive purposes only and does not imply endorsement by the author or the Department of Ecology. To request ADA accommodation for disabilities, or printed materials in a format for the visually impaired, call the Ecology ADA Coordinator at 360-407-6831 or visit ecology.wa.gov/accessibility. People with impaired hearing may call Washington Relay Service at 711. People with speech disability may call 877-833-6341. Burnt Bridge Creek Watershed Fecal Coliform Bacteria, Temperature, Dissolved Oxygen, and pH Source Assessment by Sheelagh McCarthy Environmental Assessment Program Washington State Department of Ecology Olympia, Washington Burnt Bridge Cr…FC, Temp, DO, and pH: Source Assessment Page 1 This page is purposely left blank. Burnt Bridge Cr…FC, Temp, DO, and pH: Source Assessment Page 2 Table of Contents Acknowledgments ..............................................................................................................9 Executive Summary .........................................................................................................10 Summary of Technical Approach ................................................................................10 Key Findings ................................................................................................................11 Fecal Coliform Bacteria .........................................................................................11 Temperature and Shade..........................................................................................12 Dissolved Oxygen and pH .....................................................................................12 Introduction ......................................................................................................................13 Water Quality Standards ..............................................................................................14 Bacteria ..................................................................................................................15 Temperature ...........................................................................................................15 Dissolved Oxygen ..................................................................................................16 pH ...........................................................................................................................16 Watershed Description .................................................................................................17 Hydrology & Hydrogeology ..................................................................................17 Climate ...................................................................................................................18 Land Use ................................................................................................................20 Other Nonpoint Sources .........................................................................................25 Habitat and Vegetation ..........................................................................................26 Current Restoration Work ......................................................................................26 Field Methods ...................................................................................................................28 Fixed-Network Sampling .............................................................................................28 Storm Sampling ...........................................................................................................30 Hemispherical Photographs .........................................................................................30 Continuous streamflow and groundwater studies ........................................................30 Analytical Methods ..........................................................................................................31 Bacteria Analytical Framework ...................................................................................31 Statistical Rollback Analysis .................................................................................31 Loading Summary ..................................................................................................32 Shade Analysis .............................................................................................................32 Current Effective Shade .........................................................................................33 System Potential Effective Shade ..........................................................................33 HemiView Analysis ...............................................................................................34 Data Quality Assessment .................................................................................................35 Data Quality .................................................................................................................35 Field Measurements .....................................................................................................35 Hydrolab Measurements ........................................................................................35 Flow and Channel Measurements ..........................................................................36 Burnt Bridge Cr…FC, Temp, DO, and pH: Source Assessment Page 3 Continuous Temperature ........................................................................................36 Winkler DO Samples .............................................................................................37 Lab Results...................................................................................................................37 Precision for Bacteria Field Replicates ..................................................................37 Precision for Lab Duplicates ..................................................................................38 Results ...............................................................................................................................39 Fecal Coliform Bacteria ...............................................................................................39 Loading Summary ..................................................................................................41 Storm Events Results .............................................................................................43 Statistical Rollback Results ....................................................................................44 Streamflow and Hydrogeometry ..................................................................................47 Temperature .................................................................................................................48 SEH America Facility ............................................................................................50 Shade Results ...............................................................................................................52 Dissolved Oxygen Summary .......................................................................................56 pH Summary ................................................................................................................57 City of Vancouver Water Quality Monitoring .............................................................58 City of Vancouver Annual Monitoring Data and Report.......................................58 Watershed Health Assessment Report ...................................................................60 Subbasin Summary ..........................................................................................................61 Upper Burnt Bridge Creek ...........................................................................................61 Fecal Coliform Bacteria .........................................................................................62 Temperature and Shade..........................................................................................64