Groundwater Modelling of the Edisto River Basin, South Carolina

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The USGS SAWSC in cooperation with the South Carolina Department of Natural Resources (SCDNR) will use an existing, published groundwater-flow model of the South Carolina Coastal Plain aquifers and confining units to simulate current groundwater conditions and future water-use scenarios developed by SCDNR. The published groundwater-flow model was constructed using existing hydrogeologic and geospatial information to represent nine separate regional aquifers and confining units within the Atlantic Coastal Plain aquifer system and was calibrated using an inverse modeling parameter-estimation (PEST) technique. A total of 36,844 water-level observations from 3,591 wells from 1901 to 2015 were used in the model calibration process.

These new simulations will be used by SCDNR to forecast future groundwater availability in the context of future water demands in the Edisto River basin, and to evaluate the effectiveness of groundwater management strategies in ensuring water availability and supplementing projected future water demands in the basin.

Background: 

In 2018, the South Carolina Department of Natural Resources (SCDNR) convened a State Water Planning Process Advisory Committee (PPAC) to develop a multi-faceted framework for state-wide water planning. The work of the PPAC culminated in a report, South Carolina State Water Planning Framework (Planning Framework), in October 2019 (South Carolina Department of Natural Resources, 2019). The Planning Framework describes the contents of, and the process for, developing a stakeholder-driven water supply plan (River Basin Plan), which ensures current and future water demands can be met over a 50-year planning horizon (Planning Horizon). A River Basin Plan will be developed for each of the State’s eight designated planning basins – Broad, Catawba, Edisto, Pee Dee, Salkehatchie, Saluda, Santee, and Savannah. The Planning Framework is available for review and download at http://hydrology.dnr.sc.gov/state-and-river-basin-planning.html

Map of Edisto River Basin, South Carolina

Map of Edisto River Basin, South Carolina

(Public domain.)

The Edisto basin was chosen as the first planning basin that will implement the Planning Framework. A River Basin Council (RBC) consisting of 22 stakeholders representing eight water-interest categories has been convened by SCDNR and will be responsible for developing the plan.

The U.S. Geological Survey (USGS) South Atlantic Water Science Center (SAWSC) would be part of a Planning Team consisting of SCDNR, the South Carolina Department of Health and Environmental Control (SCDHEC), Clemson University, and CDM-Smith, Inc. SCDNR serves as the primary oversight organization in the planning process and is responsible for ensuring the Planning Framework is implemented appropriately and for providing technical oversight and support for the surface water and groundwater availability assessments.

 

 

Problem:

Sound, long-term management of South Carolina’s (SC) water resources is vital to the continued economic prosperity of the state and to the well-being of its citizens and environment. Increased demand resulting from population and economic growth will increase competition for water across the state, particularly during droughts when the resource is most limited (South Carolina Department of Natural Resources, 2019). Recent droughts have highlighted the importance of developing long-term, comprehensive water resource management plans to allow for the continued growth of the state’s population and economy, while protecting the state’s water resources for generations to come.