Matthew A. Jennette Alison B. Rogerson Andrew M. Howard Delaware Department of Natural Resources and Environmental Control Division of Watershed Stewardship 820 Silver Lake Blvd, Suite 220 Dover, DE 19904 LeeAnn Haaf Danielle Kreeger Angela Padeletti Kurt Cheng Jessie Buckner Partnership for the Delaware Estuary 110 South Poplar Street, Suite 202 Wilmington, DE 19801 The citation for this document is: Jennette, M.A., L. Haaf, A.B. Rogerson, A.M. Howard, D. Kreeger, A. Padeletti, K. Cheng, and J. Buckner. 2014. Condition of Wetlands in the Christiana River Watershed. Delaware Department of Natural Resources and Environmental Control, Watershed Assessment and Management Section, Dover, DE and the Partnership for the Delaware Estuary, Wilmington, DE. ii Christina River Wetland Condition ACKNOWLEDGEMENTS Funding for this project was provided by EPA Region III Wetland Program Development Grant Assistance # CD-96312201-0, EPA National Estuary Program, the Delaware Department of Natural Resources, and the DuPont Clear into the Future program. Technical support and field research was made possible by the contributions of many individuals. Tracy Quirk and Melanie Mills from the Academy of Natural Science of Drexel University (ANS) for the collection and analysis of Site Specific data, and assistance with RAM data collection and analysis. Tom Kincaid and Tony Olsen with the EPA Office of Research and Development Lab, Corvallis, Oregon provided the data frame for field sampling and statistical weights for interpretation. Kristen Kyler and Rebecca Rothweiler participated in many field assessments under a myriad of conditions. Maggie Pletta and Michelle Lepori-Bui were helpful with revisions on drafts of the report, as well as producing the cover art for the final document. Christina River Watershed Wetland Condition Report iii CONTENTS Executive Summary .........................................................................................................................1 Introduction ......................................................................................................................................3 Watershed Overview ........................................................................................................................6 2.1 Geology and Hydrogeomorphology .....................................................................................6 2.2 Watershed History and Land-use .........................................................................................7 2.3 Wetland Resources...............................................................................................................9 Section 1: Condition of Wetlands in the Christina River Watershed ............................................11 Methods..........................................................................................................................................11 3.1 Changes to Wetland Acreage .............................................................................................11 3.2 Field Site Selection ............................................................................................................11 3.3 Data Collection ..................................................................................................................12 3.3.1 Landowner Contact and Site Access....................................................................... 12 3.3.2 Assessing Tidal Wetlands ....................................................................................... 12 3.3.3 Assessing Non-tidal Wetland Condition ................................................................. 15 3.4 Presenting Wetland Condition ...........................................................................................17 Results ............................................................................................................................................20 4.1 Landscape Analysis of Changes in Wetland Acreage .......................................................20 4.2 Landowner Contact and Site Access ..................................................................................21 4.3 Condition of Tidal Wetlands ..............................................................................................22 4.4 Condition of Non-tidal Wetlands .......................................................................................24 4.4.1 Non-tidal Flat Wetland Condition .......................................................................... 24 4.4.2 Non-tidal Riverine Wetland Condition ................................................................... 27 4.4.3 Non-tidal Depression Wetland Condition ............................................................... 28 4.5 Overall Condition and Watershed Comparison .................................................................29 Management Recommendations ....................................................................................................30 Literature Cited ..............................................................................................................................32 Appendix A: Qualitative Disturbance Rating (QDR) Descriptions .............................................35 Appendix B: DERAP Stressor Codes and Definitions ..................................................................36 Appendix C: DERAP IWC Stressors and Weights........................................................................38 Appendix D: MidTRAM Raw Data and Metric Scores from Estuarine Sites in the Christina River Watershed.............................................................................................................................40 Appendix E: DERAP Wetland Assessment Stressor Checklist for Non-tidal Flat Wetlands in the Christina River Watershed .............................................................................................................43 iv Christina River Wetland Condition Appendix F: DERAP Wetland Assessment Stressor Checklist for Non-tidal Riverine Wetlands in the Christina River Watershed .......................................................................................................46 Appendix G: DERAP Wetland Assessment Stressor Checklist for Non-tidal Depression Wetlands in the Christina River Watershed ...................................................................................49 FIGURES Figure 1. Location of the Christina River Watershed and the major basins of Delaware. Watersheds at the Hydrologic Unit Code 10 scale are outlined in gray. ........................................ 6 Figure 2. Land cover of the Christina River watershed based on 2005 (PA), 2007 (DE), and 2010 (MD) Land-use/Land-cover datasets. ............................................................................................. 7 Figure 3. Pre- and post-construction alignment of the Christina River following the completion of Interstate 95. The pre-construction channel boundary is outlined in orange, and the current alignment southeast of Newport is outlined in red. ........................................................................ 8 Figure 4. Distribution of wetlands in the Christina River watershed, based on 2007 mapping. .. 10 Figure 5. Standard assessment area, subplot locations, and buffer used to collect data for the Mid-Atlantic Tidal Rapid Assessment Method Version 3.0. ........................................................ 12 Figure 6. Standard assessment area and buffer used to collect data for the Delaware Rapid Assessment Procedure Version 6.0. .............................................................................................. 15 Figure 7. An example CDF showing wetland condition. The red line is the population estimate. The orange and green dashed lines show the breakpoints between condition categories. ........... 19 Figure 8. Estimated historic and more current wetland coverage in the Christina River watershed. ....................................................................................................................................................... 20 Figure 9. Ownership of sampled wetland sites in the Christina River watershed (left) and success rates for sampling private wetland sites (right). ............................................................................ 21 Figure 10. Location of wetland assessments performed in the Christina River watershed in 2011. ....................................................................................................................................................... 22 Figure 11. Habitat, hydrology, and buffer attribute group scores from tidal wetlands in the Christina River watershed. ............................................................................................................ 23 Figure 12. Proportion of tidal freshwater wetlands by condition class for the Christina River watershed, DE. .............................................................................................................................. 23 Figure 13. The cumulative distribution function for tidal wetlands in the Christina watershed. The orange and green dashed lines signify the condition category breakpoints dividing severely stressed from moderately and minimally stressed portions of the tidal wetland population. ....... 24 Figure 14. Cumulative distribution function for non-tidal flat wetlands in the Christina River watershed. Condition scores for the wetland population are represented as the red line