South Carolina Sea Grant

Reduced river flows during drought threaten fresh water supplies in coastal areas because the lower flows allow the salt water wedge to penetrate further inland from estuaries than is normal.  During droughts over the past decade, some coastal drinking water systems and industries monitored threats to fresh drinking water and industrial water intakes due to this salinity intrusion; some have even had to periodically take intakes offline due to high salinities that can damage drinking water treatment systems and industrial equipment. To help decision-makers understand how the frequency of salt water intrusion events may change under future precipitation and sea level scenarios, the S.C. Sea Grant Consortium, the Carolinas Integrated Sciences and Assessments center at the University of South Carolina, and the USGS S.C. Water Science Center adapted an existing decision support system for salinity intrusion in the coastal Yadkin-Pee Dee river basin by adding climate model-based precipitation scenarios and increments of sea level rise to the Model 2 (PRISM2) decision support tool.  This modification is significant in that it allows water managers to explore how often salt-water intrusion events may occur in the Yadkin-Pee Dee River basin under conditions influenced by ongoing and future climatic change.