Agricultural Water Use in South Carolina - A Series of Investigations to Support Long-Term Planning

Author

Charles PellettFollow

Date of Award

12-2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Plant and Environmental Science

Committee Chair/Advisor

Carlyle Brewster

Committee Member

Christopher Post

Committee Member

Jeffery Allen

Committee Member

Elena Mikhailova

Committee Member

William Bridges

Abstract

Agricultural water use in South Carolina has been the subject of some public debate. While there are several sources of information available, the accuracy of the relevant data has been called into doubt. Self-reported estimates may be biased; survey sampling and extrapolation methods yield wide ranges of uncertainty; and reporting compliance or response rate can change over time.

Agricultural water users self-report that their estimates of water use volumes are less accurate than the other major sectors of water use. Center pivot irrigation is the largest and fastest growing kind of agricultural water use in SC. Since the year 2000, estimates of the extent of irrigated land have varied widely, but recently the data have begun to converge. While State and Federal sources have indicated substantial increases in irrigated area from 2010 to 2020, estimates derived using other methods indicate more modest growth. While there was significant under-reporting in the past, the State Water Use Database appears mostly complete as of this publication. The minimum threshold for the State regulatory reporting requirements, withdrawal of at least 3 million gallons per month, does not appear to exclude a significant fraction of total agricultural water use (i.e. the evidence does indicate that there are hundreds of irrigators using 2.9 million gallons per month).

Accurate estimates of agricultural water usage are needed to calibrate water availability models for long-term water planning and other purposes. This research is aimed at providing sound information with the hope of raising the level of informed discussion among stakeholders.

Recommended Citation

Pellett, Charles, "Agricultural Water Use in South Carolina - A Series of Investigations to Support Long-Term Planning" (2024). All Dissertations. 3848.
https://open.clemson.edu/all_dissertations/3848