Low-flow frequency and flow duration of selected South Carolina streams in the Catawba-Wateree and Santee River Basins through March 2012

Abstract

Part of the mission of both the South Carolina Department of Health and Environmental Control and the South Carolina Department of Natural Resources is to protect and preserve South Carolina's water resources. Doing so requires an ongoing understanding of streamflow characteristics of the rivers and streams in South Carolina. A particular need is information concerning the low-flow characteristics of streams, which is especially important for effectively managing the State's water resources during critical flow periods, such as during the historic droughts that South Carolina has experienced in the past few decades.

Selected low-flow frequency statistics for continuous-record streamgages in Georgia, 2013

“…The diversions affect the streamflow regime of a river in various ways and depend not only on where the diversions occur but also on the final outcome of the diverted water. A proper accounting of all diversions in a basin is typically difficult; therefore, most USGS low-flow analyses are made on the data as measured at the streamgage, without adjustments for diversions (Feaster and Guimaraes, 2014). In this study, streamflows were not adjusted for diversions.…”

“…Streamflows at regulated stations also are influenced by changes in climatic cycles, land use, diversions, and groundwater activities, but those changes can be mitigated, enhanced, or even offset by changes in regulation patterns. Still, trend assessments in the flow patterns are useful to help determine the suitability of a frequency analysis of data collected at a regulated streamgage (Feaster and Guimaraes, 2014).…”

“…If assessments of the historical streamflow records indicate that the regulation patterns have been relatively consistent and if the logarithm of the annual minimum flows for a given averaging period are consistent with a Pearson Type III distribution, then low-flow statistics can be computed for the regulated station with the understanding that using those statistics for future planning assumes relatively similar regulation patterns will occur in the future (Riggs, 1972;Feaster and Guimaraes, 2014).…”

“…For those streamgages on regulated streams, low-flow frequency curves are based on the longest period of homogeneous record under current conditions. For this study, the flow patterns at regulated streams were assessed for homo geneity using the quality-assurance and quality-control computer programs described in Feaster and Guimaraes (2014). The streamgages on regulated streams are noted in table 1.…”