1. Shoreline Stabilization and Changes in Sediment Composition Associated with Small-Scale Oyster Reefs in South Carolina Michael Hodges Nancy Hadley Loren Coen Steve Roth Lindsay Goodwin Majbritt Bolton-Warberg

2. The South Carolina Oyster Restoration and Enhancement Program (SCORE) was established to: Involve citizens in oyster restoration activities Educate the public and foster environmental stewardship Utilize volunteer assistance to recycle shell Use volunteer manpower to establish multiple research platforms annually along South Carolinas coast and aid in data collection

3. In Five Years, SCORE Has Established 128 reefs (  2,115m 2 ) at 29 sites along 320 km of coastline Encompassed a broad spectrum of environmental conditions Involved over 2,000 volunteers/over 15,000 hours of service Trained weekly water quality monitors at most of these sites

5. Typical Site Layout 14 m 2

6. A Sites Firmness Can Vary Depending on Sediment Profile Shell Sand Fine Sediment

7. We Monitor Regularly for the Following 1.Marsh erosion 2.Marsh expansion 3.Sedimentation rate and composition 4.Chlorophyll a 5.Water quality (pH, DO, Salinity, Water Clarity, Temp) 6.Utilization by other organisms 7.Population parameters 8.Reef observations

8. Marsh Erosion Natural phenomenon caused by winds, waves, currents, and tides Destabilization of fringing marsh is a cause for concern and seriously affected by erosion Human activities such as boat traffic, wetland drainage, and dredging increase rates of erosion Oysters act as natural breakwaters for fringing marsh to help decrease the rate of shoreline loss

9. Marsh Erosion

10. SCORE Erosion Site Results, 2001-7/06 Mean Overall Erosion Monthly Mean Erosion Rates Mean monthly rates ranged from 1.3 – 5.5 cm Overall shoreline losses ranged from 40.5 – 331.3 cm. Numbers in columns indicate total length of assessment, 21 – 59 mo.

11. Erosion Rates Are Decreasing With Time Behind Reefs

12. Spartina Expansion Although marsh edge continues to retreat, overtime Spartina is growing seaward Expansion has been noted at 10 sites, significant expansion at 9 sites Generally takes place 2.5- 3 years post-construction Appears to be associated with the accumulation of soft sediments and stabilization behind reefs Has grown seaward as much as 13 meters at some sites

13. Marsh Expansion These are totals for the original reefs deployed at these sites, negative numbers represent retreat of marsh Site Mean Expansion (m) Max Expansion at Single Reef (m) Length of Deployment (months) Kiawah029 Boy Scout-0.63.565 Waddell3.36.352 Dataw3.56.265 Palmetto4.68.565 Trask7.613.952

14. Spartina Expansion at Boy Scout 2002 2003 2004 2006

15. 20012002 Spartina Expansion at Dataw Island 2002 2003 2004 2006

16. Port Royal Sound (High Energy) Expansion 2003 2004 2006

17. Charleston Harbor (High Energy) Expansion 2001 2004 2006

18. Marsh Expansion Along Entire Shoreline 2002 2005

19. (m)

20. Sediment Depth Poles Used to measure rate at which sediments settle at reefs Poles are 40 cm in length Placed behind reefs Measured quarterly or bi-annually

21. Sediment Depth Poles

22. Sediment Analysis

23. Sediment Grain Size Analysis We wanted to examine pre-construction sediment composition vs. post- construction sediment composition There is a significant difference in the sediment composition accumulating behind reefs vs. sediment composition not associated with constructed reefs (p=.003) At all sites monitored, there has been an increase in the amount of fine sediments settling at our reefs. The sediment is either washing down from above salt marshes or settling out with reduced flow rates around new reefs

24. Changes in Sediment Composition AVG  29% (13 sites)

25. % Composition Site/Years

26. Things To Consider When Constructing Reefs Boat Ramp Spacing Between Reefs

27. Ways to Address Sediment and Shoreline Changes Elevate Back Row Add Stumps Behind Reef

28. Conclusions Spacing of reefs is important when considering shoreline protection Reef deployment aids in marsh expansion Sediment compositions are changing at sites as reefs are introduced Early adaptive management techniques will help to deal with excessive sedimentation Using volunteers will help facilitate work load and increase community awareness on environmental concerns Filling knowledge gaps of sheltered coastal systems

29. Future Objectives Continue to intensely monitor erosion behind reefs and areas not associated with reefs to see if they differ significantly Continue to monitor changes in sediment composition and marsh expansion Use findings to establish oyster restoration metrics Construct more reefs in Northern part of SC

30. Acknowledgements All SCORE Volunteers Community Partners SRS Staff (past and present) Jason Comer and Andy Jennings Environmental Action Volunteers Beaufort Marine Institute Wesley Willis (RIP) Mr. T