DISTRICT OF COLUMBIA WETLAND CONSERVATION PLAN March 2020 Prepared Under: Grant No. 2015-1504-WQD-01 Prepared by: Wetland Studies and Solutions Inc. 5300 Wellington Branch, Drive, Suite 100 Gainesville, VA 20155 in collaboration with: Department of Energy and Environment Watershed Protection Division 1200 First Street NE Washington, DC 20002 https://doee.dc.gov/ iii Acknowledgements Authors Department of Energy and Environment Jennifer Dietzen Rebecca Diehl Wetland Studies and Solutions, Inc. Jessica Campo Sarah Wills Ally Robinson Mike Bowser Manuel Larson-Santos Melissa Letosky Maggie Graham Frank Graziano Brian Chromey Ben Rosner Editors Geoff Brown, DOEE-Regulatory Review Scott Drew, formerly with DOEE - Natural Resources Sherry Schwechten, formerly with DOEE-Natural Resources To update the District of Columbia’s Wetland Conservation Plan, Wetland Studies and Solutions, Inc. (WSSI) conducted months of field work and data collection, including a comprehensive District-wide inventory of wetlands, methodology development, technical analysis, and review. WSSI also developed the Wetland Registry geodatabase, Wetland Enhancement and Restoration Evaluation Tool, and Creation Suitability Guidance Documents. DOEE wrote several chapters in this document and assisted with data review and editing. iv Contents Executive Summary ................................................................................................................. 1 Chapter 1 Overview of Wetland Conservation Plan Updates .......................................... 3 1.1 District of Columbia Wetland Conservation Plan Updates ..................................... 3 1.2 What are Wetlands? ..................................................................................................... 4 1.3 Wetlands: History and Impacts .................................................................................. 12 Chapter 2 Inventory and Assessment of Wetlands ......................................................... 19 2.1 Wetlands Mapping and Registry ............................................................................... 19 2.2 Results ............................................................................................................................ 33 2.3 Summary of the District Wetlands Mapped During the 2017 WCP Update ...... 182 Chapter 3 Wetland Conservation Plan Implementation ................................................231 3.1 Current Regulatory Controls and Programs........................................................... 231 3.2 District Wetland Regulations .................................................................................... 233 3.3 Wetland Registry ........................................................................................................ 235 3.4 Wetland Enhancement and Restoration Evaluation Tool and Wetland Creation Suitability Guidance Documents ............................................................................ 236 3.5 DOEE Divisions that Protect Wetlands and Water Quality ................................... 237 3.6 Sustainable DC 2.0 .................................................................................................... 238 3.7 Wetland Restoration, Enhancement, Creation, and Preservation Portfolio ..... 239 3.8 Wetland Registry Maintenance, Monitoring, and Wetland Conservation Plan Updates ....................................................................................................................... 239 3.9 Climate Change Resilience ..................................................................................... 240 3.10 Living Shorelines ......................................................................................................... 240 3.11 In-Lieu Fee Program/Mitigation Bank ..................................................................... 241 3.12 Stream Registry .......................................................................................................... 242 3.13 Wetlands of Special Concern Designation ........................................................... 242 References 243 Appendix A Property Access Request Letter .................................................................... A-1 Appendix B National Park Service and National Arboretum Draft Revocable Permits . B-1 Appendix C Wetland Enhancement and Restoration Evaluation (WERE) ....................... C-1 Appendix D Wetland Guidance Documents .....................................................................D-1 Appendix E Wetland Determination Data Forms............................................................... E-1 Appendix F 2017 District of Columbia Plant List ................................................................ F-1 Appendix G 2017 Overall Wetland Registry Map ............................................................. G-1 v Appendix H Cowardin Classification Diagram ..................................................................H -1 Appendix I Method for Inventorying and Evaluating Freshwater Wetlands in New Hampshire......................................................................................................... I-1 Appendix J District Wetland Function and Value Checklist ............................................. J-1 Appendix K DOEE Additional Information Checklist ......................................................... K-1 Appendix L Representative Site Photographs ................................................................... L-1 Appendix M New Hampshire Method Raw Data .............................................................. M-1 Appendix N District Wetland Function and Value Checklist Raw Data .......................... N-1 Appendix O 2017 Overall Wetland Registry Detail Maps ................................................. O-1 Appendix P 2017 Mapped Stream Segments in the District ............................................. P-1 vi List of Tables Table 2.1 Desktop Reconnaissance Datasets ....................................................................... 20 Table 2.2 Classification of Wetlands as High, Average, or Low Relative Value (District Method) ....................................................................................................................................... 33 Table 2.3 2017 Mapped Wetlands by Cowardin Classification .......................................... 38 Table 2.4 Inventory of District Wetlands.................................................................................. 49 Table 2.5 Acreage of 2017 District Wetlands Mapped Within NPS Land ........................... 82 Table 2.6 New Hampshire Method Summary ........................................................................ 85 Table 2.7 District Wetland Function and Value Checklist: Relative Value of Mapped District Wetlands ....................................................................................................................... 104 Table 2.8 Wetland Relative Value by Wetland Group ....................................................... 132 Table 2.9 WERE Tool Score Summary .................................................................................... 140 Table 2.10 Summary of Potential Wetland Creation Sites .................................................. 178 vii List of Figures Figure 2-1 Physiographic region map. .................................................................................... 23 Figure 2-2 Organization of GIS information. ........................................................................... 27 Figure 2-3 2017 mapped wetlands and potential creation sites in the District. ................ 34 Figure 2-4 Wetland detail map legend. ................................................................................. 35 Figure 2-5 1997 and 2017 mapped District wetland comparison. ...................................... 37 Figure 2-6 Tidal and nontidal 2017 update of mapped wetlands in the District. ............. 47 Figure 2-7 2017 mapped District wetlands per watershed. ................................................. 76 Figure 2-8 2017 mapped District wetlands per ward. ........................................................... 77 Figure 2-9 2017 mapped District wetlands per quadrant. ................................................... 78 Figure 2-10 2017 mapped District wetland acreage and total percentage by wetland group. ........................................................................................................................................... 79 Figure 2-11 2017 mapped District wetland acreage and Total Percentage by watershed. ................................................................................................................................... 80 Figure 2-12 2017 mapped District wetland acreage and Total Percentage by ward. ... 80 Figure 2-13 2017 mapped District wetland acreage and Total Percentage by quadrant. ....................................................................................................................................................... 81 Figure 2-14 National Park Service land within the District .................................................... 83 Figure 2-15 2017 relative value of mapped wetlands in the District. ............................... 103 Figure 2-16 District Wetland Function and Value Checklist: 2017 mapped wetland relative value count per wetland group. .............................................................................. 129 Figure 2-17 District Wetland Function and Value Checklist;