Water Resources Research Act Program

Details for Project ID 2012SC81B

A Modeling Study of Water Shortages in the Savannah River Basin: Sensitivity of Water Availability to Evaporative Loss and Climate Change

Institute: South Carolina
Year Established: 2012 Start Date: 2012-05-01 End Date: 2013-04-30
Total Federal Funds: $59,998 Total Non-Federal Funds: $119,330

Principal Investigators: Nigel Kaye, John Saylor

Abstract: Problem: Growing demands on water resources in the Savannah River basin will ultimately constrain economic growth in South Carolina and Georgia. While water resources in this basin are currently plentiful, the growth in population, industry and recreational activity will ultimately consume more water than is available. Plans for the siting of additional power plants along the Savannah will only exacerbate this emerging problem. As the Savannah River water supply becomes more constrained, demands for more accurate and sophisticated predictions will be needed of the basin scale water cycle. Currently, models such as HEC ResSim are used to predict and simulate lake levels in the Savannah River basin. These models rely on historical data to predict evaporative losses from the reservoirs in this basin. That is, evaporative loss, in inches per acre per day for a given month are obtained from the historical record, and are used to predict evaporation. This is then used as an input in the model. Such an approach is satisfactory if one is interested only in predicting annual averages. However, in the future scenario described above, water constraints will be severe enough to require accurate predictions of water supply on a weekly basis, particularly during drought years. Such a predictive capability will require an accurate parameterization of evaporative loss. However, it is unclear exactly when, and under what specific conditions this will occur. Objectives: The broad objectives of the proposed research are (1) to determine the amount of increase in water usage on the Savannah River basin at which evaporative loss will represent a large enough fraction of available water to make inadequate current predictive tools of water levels; (2) to use models of population and economic growth to determine when this will occur; (3) to determine how climate change will potentially affect (1) and (2), above. Methods: The aforementioned objectives will be attained via a sensitivity analysis of the HEC ResSim model. Specifically: (1) comparisons will be made with the evaporative loss obtained via the standard method, and that obtained via turbulence models of evaporative transport; (2) population dynamics and economic growth models will be used to predict increases in water withdrawals as a function of time. This, in turn, will be used to predict when differences in current evaporative loss predictions and more sophisticated turbulence model predictions are a significant fraction of the available water in the Savannah River basin. Finally, models of climate change will be used to ascertain potential growth in errors of HEC ResSim.