National Park Service U.S. Department of the Interior Water Resources Division Technical Report NPS/NRWRD/NRTR-2005/332 Natural Resource Program Center ASSESSMENT OF COASTAL WATER RESOURCES AND WATERSHED CONDITIONS AT CUMBERLAND ISLAND NATIONAL SEASHORE, GEORGIA Merryl Alber, Janice Flory, and Karen Payne The National Park Service Water Resources Division is responsible for providing water resources management policy and guidelines, planning, technical assistance, training, and operational support to units of the National Park System. Program areas include water rights, water resources planning, regulatory guidance and review, hydrology, water quality, watershed management, watershed studies, and aquatic ecology. Technical Reports The National Park Service disseminates the results of biological, physical, and social research through the Natural Resources Technical Report Series. Natural resources inventories and monitoring activities, scientific literature reviews, bibliographies, and proceedings of technical workshops and conferences are also disseminated through this series. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the National Park Service. Copies of this report are available from the following: National Park Service (970) 225-3500 Water Resources Division 1201 Oak Ridge Drive, Suite 250 Fort Collins, CO 80525 National Park Service (303) 969-2130 Technical Information Center Denver Service Center P.O. Box 25287 Denver, CO 80225-0287 ii Assessment of Coastal Water Resources and Watershed Conditions at Cumberland Island National Seashore Dr. Merryl Alber1, Dr. Janice Flory1, and Dr. Karen Payne2 1Department of Marine Sciences 2Marine Extension Service University of Georgia Athens, GA 30602 Submitted to the National Park Service May 2005, revised for web access August 2005 This report was prepared under Task Order J2380 03 0237 of the Gulf Coast Cooperative Ecosystem Studies Unit (agreement H5000 02 A413) TABLE OF CONTENTS Executive Summary........................................................................................................................ 2 A. Park Description........................................................................................................................ 7 A1. Background ......................................................................................................................... 7 A1a. Setting.............................................................................................................................. 7 A1b. Land cover..................................................................................................................... 10 A1c. History and human utilization....................................................................................... 16 A2. Hydrologic information..................................................................................................... 19 A2a. Oceanographic and climatic setting .............................................................................. 19 A2b. Hydrology ..................................................................................................................... 21 A2c. Water resources............................................................................................................. 23 A3. Biological resources.......................................................................................................... 27 A3a. Marine habitats and species........................................................................................... 27 A3b. Intertidal habitats and species ....................................................................................... 31 A3c. Upland habitats and species .......................................................................................... 32 A3d. Freshwater bodies ......................................................................................................... 34 B. Water Resources Assessment.................................................................................................. 36 B1. Water quality..................................................................................................................... 36 B1a. Data sources................................................................................................................... 36 B1b. Water quality in Cumberland Sound and surrounding estuarine areas ......................... 38 B1c. Water quality on Cumberland Island............................................................................. 46 B2. Water quality impairments................................................................................................ 47 B2a. Nearfield impairments in Cumberland Island and surrounding estuarine areas............ 48 B2b. Farfield impairments in Cumberland Island and surrounding estuarine areas.............. 50 B3. Sources of pollutants ......................................................................................................... 52 B3a. Point sources of pollutants............................................................................................. 52 B3b. Nonpoint sources........................................................................................................... 62 C. Other Water Resource Issues of Concern ............................................................................... 66 C1. Coastal development ......................................................................................................... 66 C1a. Population and land use................................................................................................. 66 C1b. Water withdrawals......................................................................................................... 68 C2. Species of concern............................................................................................................. 70 C2a. Rare and protected species ............................................................................................ 70 C2b. Invasive and introduced species.................................................................................... 77 C2c. Feral and game species.................................................................................................. 80 C3. Physical impacts................................................................................................................ 82 C3a. Dredging........................................................................................................................ 82 C3b. Boat traffic..................................................................................................................... 83 C3c. Shoreline change ........................................................................................................... 84 C3d. Island alterations ........................................................................................................... 85 D. Summary and Recommendations............................................................................................ 88 D1. Condition overview........................................................................................................... 88 D2. Recommendations............................................................................................................. 89 D2a. Data access/management............................................................................................... 90 D2b. Water quality................................................................................................................. 92 ii D2c. Biological resources and habitats.................................................................................. 93 D2d. Hydrology ..................................................................................................................... 94 References..................................................................................................................................... 96 Appendices.................................................................................................................................. 107 List of Figures Figure 1. Location map of Cumberland Island in the southeastern United States......................... 8 Figure 2. Location of Cumberland Island in Camden County, Georgia along with jurisdictional boundaries............................................................................................................................... 9 Figure 3. 1998 land cover map of Camden County, Georgia and the Cumberland-St. Simon’s watershed .............................................................................................................................. 11 Figure 4. Land cover -- Cumberland and Little Cumberland Islands.......................................... 13 Figure 5. Hammocks within the CUIS park boundary ................................................................ 16 Figure 6. Trends in Camden County population: change in total population.............................. 19 Figure 7. U.S. census tract data for Camden County, Georgia, showing the total number of people per tract...................................................................................................................... 20 Figure 8. Geologic framework for coastal groundwater in southern Georgia ............................. 22 Figure 9. Place names on Cumberland Island.............................................................................