Determining the Ordinary High Water Mark for Shoreline Management Act Compliance in Washington State October 2016 Final Review Publication no. 16-06-029 Template Publication and Contact Information This report is available on the Department of Ecology’s website at https://fortress.wa.gov/ecy/publications/SummaryPages/1606029.html For more information contact: Shorelands and Environmental Assistance Program P.O. Box 47600 Olympia, WA 98504-7600 Phone: 360-407-6000 Washington State Department of Ecology - www.ecy.wa.gov o Headquarters, Olympia 360-407-6000 o Northwest Regional Office, Bellevue 425-649-7000 o Southwest Regional Office, Olympia 360-407-6300 o Central Regional Office, Yakima 509-575-2490 o Eastern Regional Office, Spokane 509-329-3400 Accommodation Requests: To request ADA accommodation including materials in a format for the visually impaired, call Ecology at 360-407-6000. Persons with impaired hearing may call Washington Relay Service at 711. Persons with speech disability may call TTY at 877-833-6341. Determining the Ordinary High Water Mark for Shoreline Management Act Compliance in Washington State by; Paul S. Anderson, Susan Meyer, Dr. Patricia Olson, Erik Stockdale Shorelands and Environmental Assistance Program Washington State Department of Ecology Olympia, Washington Table of Contents Page Acknowledgements ..............................................................................................................3 Executive Summary .............................................................................................................4 Chapter 1 - Introduction .......................................................................................................8 1.1 Importance of Accurate Ordinary High Water Mark Determinations .....................8 1.2 Purpose of the Document .........................................................................................9 1.3 Organization of This Document.............................................................................10 1.4 Target Audience for This Document .....................................................................11 Chapter 2 – Determining the OHWM ................................................................................12 2.1 The Ordinary High Water Mark Defined...............................................................12 2.2 The Three Criteria of an Ordinary High Water Mark ............................................13 2.3 Ordinary High Water Mark Considerations ...........................................................15 2.4 Reasons for Systematically Determining the OHWM ...........................................18 2.5 How to Determine the OHWM ..............................................................................19 2.5.1 Step 1: Office assessment of landscape and geomorphic features .............19 2.5.2 Step 2: Field assessment .............................................................................19 2.5.3 Step 3: Document findings .........................................................................20 2.5.4 Step 4: Hydrologic assessment (if needed) ................................................21 2.6 Special Circumstances ...........................................................................................21 Chapter 3 – Streams ...........................................................................................................22 3.1 Introduction ............................................................................................................22 3.2 Definining the OHWM ..........................................................................................23 3.2.1 Field indicator descriptions ........................................................................24 3.2.2 Common misunderstandings of stream OHWM ........................................33 3.2.3 Special circumstances .................................................................................38 3.3 Office Assessment .................................................................................................41 3.4 Field Assessment ...................................................................................................59 - Set up transect(s) from the water’s edge to the upland........................................60 - Identify vegetation and soil indicators along transect starting at water’s edge. ..60 Chapter 4 – Tidal Waters ...................................................................................................66 4.1 Introduction ............................................................................................................66 4.2 Defining the Ordinary High Water Mark...............................................................67 4.2.1 Field indicators descriptions .......................................................................76 4.2.2 Common misunderstandings ....................................................................101 4.3 Office Assessment ...............................................................................................103 3.4 Field Assessment .................................................................................................108 Chapter 5 – Lakes ............................................................................................................110 5.1 Introduction ..........................................................................................................110 5.1.1 Origin and patterns of lakes ......................................................................111 5.2 Defining the OHWM ...........................................................................................112 5.2.1 Definition of lakes in the SMA ................................................................112 1 5.2.2 Field indicator descriptions ......................................................................114 5.2.3 Common misunderstandings of lake OHWM ..........................................133 5.2.4 Special circumstances and considerations ................................................134 5.3 Office Assessment ...............................................................................................138 5.4 Field Assessment .................................................................................................139 5.4.1 General observations ................................................................................139 5.4.2 Identify lower and upper boundaries of OHWM using transect(s): .........140 5.4.3 Field verification of preliminary OHWM determination .........................140 Chapter 6 – Associated Wetlands and River Deltas ........................................................141 6.1 Introduction ..........................................................................................................141 6.2 Office Assessment ...............................................................................................149 6.2.1 Step 1: Assess landscape and geomorphic features ..................................150 6.2.2 Step 2: Choose potential locations for field survey ..................................151 6.3 Field Assessment .................................................................................................151 6.3.1 Conducting the field assessment ..............................................................151 6.3.2 Description and rationale for field indicators ...........................................152 6.3.3 Proximity indicators .................................................................................153 6.3.4 Influence indicators ..................................................................................153 Appendices .......................................................................................................................155 Appendix A: Field data form .....................................................................................156 Appendix B: Plant species distribution across OHWM gradient ...............................160 Appendix C: Useful internet links for making OHWM determinations ....................177 Streams ..............................................................................................................177 Tidal Waters ......................................................................................................178 Lakes ..................................................................................................................178 Wetlands ............................................................................................................179 Soil .....................................................................................................................179 Plants .................................................................................................................179 Aerial Photographs and Interactive Mapping ....................................................180 Appendix D: Geomorphic examples and indicators ..................................................182 Appendix E: Example report outline .........................................................................198 Appendix F: Glossary ................................................................................................199 Appendix G: Comparison of different OHWM definitions in various statutes and rules ....................................................................................................................................215 Appendix H: References