Saltwater Intrusion

Transcript

1. Saltwater Intrusion Stress on Hilton Head Island TJ Haigler Department of Geological and Environmental Sciences, Appalachian State University, Boone, North Carolina
2. Hilton Head Island, SC - Coastal reliance on freshwater aquifers - Upper Floridian Aquifer (UFA) approx. 30m thick - Beaufort County, SC reliance on UFA since 1880s - Hilton Head reliance since 1956 Adapted from Payne (2010)
3. Over pumping reversed the groundwater gradient - Savannah, Georgia located less than 30 km SW of HHI - Reversed groundwater gradient - Now much steeper Adapted from Payne (2010)
4. Tracking chloride levels is a key indicator in saltwater intrusion rates - Numerous dissolved solids in water - Chloride dissociation indicator - Chloride concentration already well above average for safe usage Adapted from Falls et al. (2005)
5. Shallow confining unit under northern HHI - Shallow confining unit susceptible to erosion - Increased number of saltwater springs in aquifer - Direction and rate of saltwater movement increases intrusion rates Adapted from Provost et al. (2006)
6. Aquifer storage recovery (ASR) wells store freshwater for later use South Florida Water Management District
7. Previous ASR well met peak summer standards in 2012 - 10 more wells on northern HHI - Test cycles last 2 months - Keep testing for 2 years Adapted from Pyne (2015)
8. “Peak summer performance” in perspective. Tourism rates, and national spotlights Mandy Matney, Fitsnews
9. “Peak summer performance” in perspective. Tourism rates, and national spotlights RBC Heritage
10. “Peak summer performance” in perspective. Tourism rates, and national spotlights Todd Kelly, Golfweek
11. Saltwater intrusion is constantly happening - Saltwater intrusion is going to continue to happen - Can only mitigate effects - ASR wells help dependence on UFA - Some water bans could be lifted Any Questions?
12. References Barlow, P. M., & Reichard, E. G. (2010). Saltwater intrusion in coastal regions of North America. Hydrogeology Journal, 18(1), 247. Chang, S. W., Clement, T. P., Simpson, M. J., & Lee, K. K. (2011). Does sea-level rise have an impact on saltwater intrusion?. Advances in water resources, 34(10), 1283-1291. Falls, W., Ransom, C., Landmeyer, J. E., Reuber, E. J., & Edwards, L. E. (2005). Hydrogeology, water quality, and saltwater intrusion in the upper Floridan aquifer in the offshore area near Hilton Head Island, South Carolina, and Tybee Island, Georgia, 1999-2002. U. S. Geological Survey. Klassen, J., & Allen, D. M. (2017). Assessing the risk of saltwater intrusion in coastal aquifers. Journal of Hydrology, 551, 730-745. Krause, R. E., & Clarke, J. S. (2001). Coastal ground water at risk—saltwater contamination at Brunswick, Georgia and Hilton Head island, South Carolina (No. 2001-4107). US Geological Survey. Payne, D. F. (2010). Effects of climate change on saltwater intrusion at Hilton Head Island, SC, USA. In SWIM21—21st saltwater intrusion meeting, Azores, Portugal (pp. 293-296). U. S. Geological Survey. Payne, D. F., Provost, A. M., & Voss, C. I. (2001). Preliminary numerical models of saltwater transport in coastal Georgia and Southeastern South Carolina. Georgia Institute of Technology. 2001 Georgia Water Resources Conference. Provost, A. M., Payne, D. F., & Voss, C. I. (2006). Simulation of saltwater movement in the Upper Floridan aquifer in the Savannah, Georgia-Hilton Head Island, South Carolina, area, predevelopment-2004, and projected movement for 2000 pumping conditions (No. 2006-5058). US Geological Survey. Pyne, R. D. G. (2015). Aquifer storage recovery: An ASR solution to saltwater intrusion at Hilton Head Island, South Carolina, USA. Environmental Earth Sciences, 73(12), 7851-7859. Williams, L. J., & Gill, H. E. (2010). Revised hydrogeologic framework of the Floridan aquifer system in the northern coastal area of Georgia and adjacent parts of South Carolina. U. S. Geological Survey. Zuurbier, K. G., & Stuyfzand, P. J. (2017). Consequences and mitigation of saltwater intrusion induced by short-circuiting during aquifer storage and recovery in a coastal subsurface. Hydrology and Earth System Sciences, 21(2), 1173-1188.