Water Resources Research Act Program

Details for Project ID 2006MS44B

Assessing the effectiveness of streamflow augmentation in the Sunflower River to maintain water quality and wetland integrity

Institute: Mississippi
Year Established: 2006 Start Date: 2006-03-01 End Date: 2008-02-28
Total Federal Funds: $51,006 Total Non-Federal Funds: $102,000

Principal Investigators: Gary Ervin, Todd Tietjen

Project Summary: This project will provide a quantitative ecologicalevaluation of wetland and water quality impacts resulting from groundwater supplementation to a major stream in the Lower Mississippi Alluvial Valley (LMAV). The Big Sunflower River is listed on the EPA Section 303(d) list of Impaired Waterbodies of Mississippi. Substantial decreases in the Sunflower River's late summer/early autumn base flows, as a result of agricultural withdrawals from the Mississippi River Valley Alluvial Aquifer, likely have contributed to the degraded condition of the river. The Yazoo Mississippi Delta Joint Water Management District has been managing surface and groundwater supplies since 1991 in an effort to balance the needs of agricultural water resources used with maintenance of adequate ecosystem quality in the Sunflower River and adjacent floodplains. To date, rates of streamflow augmentation have been guided exclusively by TMDL targets issued by the MS DEQ, with maximal possible rates of supplementation serving as the goal. Data are needed that demonstrate the responses of biotic and abiotic ecosystem components to varying degrees of groundwater supplementation and in contrast with other water souces (e.g., agricultural runoff, precipitation). The research we propose will provide data that will enable water district managers to optimize loading of supplemental groundwater to surface streams and wetlands during critical periods by providing: (1) an assessment of in-stream and floodplain ecological condition during markedly different hydrologic regimes int he Big Sunflower drainage system, (2) simultaneous quantitative evaluation of the effects of streamflow augmentation on aquatic resources, including in-stream primary producers and adjacent wetlands, and (3) an initial quantification of the response of biotic and abiotic parameters to a range of discharge augmentation (from no supplementation to maximal rates of existing infrastructure). As such, this project will increase the efficacy with which water district managers can plan and implement programs to augment surface water flows and storage with the LMAV, in an effort to balance societal and ecological needs.