Water Resources Research Act Program

Details for Project ID 2019KY288B

Quantifying the source of dissolved reactive phosphate in karst drainage of the Inner-Bluegrass using oxygen isotopes

Institute: Kentucky
Year Established: 2019 Start Date: 2019-06-17 End Date: 2020-06-16
Total Federal Funds: $8,800 Total Non-Federal Funds: $18,130

Principal Investigators: Dr. William Ford

Abstract: The role of dissolved inorganic phosphorus to fuel nuisance and harmful algal blooms in receiving waterbodies of eutrophic landscapes is well documented, making management of P a pressing, contemporary issue. This proposal addresses a particular need to advance techniques for quantifying dissolved reactive phosphate source apportionment in karst watersheds of central Kentucky. Both anthropogenic and allogenic sources of DRP contribute to loadings in karst watersheds of the Inner-Bluegrass; however, quantitative tools for differentiating source provenance at a watershed scale are lacking. Recently, oxygen isotopes of dissolved inorganic phosphate have been shown to provide valuable information regarding inorganic P sources and pathways in fluvial systems. We anticipate the tool to serve as a useful fingerprint of sources draining to karst springs. Specifically, we focus on the Cane Run watershed and Royal Spring groundwater basin which is a mature karst system located in the Inner-Bluegrass of Central KY. We plan to instrument agricultural and urban tributary sources in the watershed as well as the Royal Spring conduit. We will measure nutrient concentrations, water isotopes and phosphate oxygen isotope signatures for several events, specifically targeting within-event variability. Following characterization of isotopic composition of sources, we will use statistical tests to determine distinguishability of source signatures. Assuming sources are differentiable, we will utilize un-mixing modeling and uncertainty analysis (considering uncertainty in source distributions) to quantify phosphate source apportionment estimates in the Royal Spring groundwater basin. Funding for this project would serve as a major component of a M.S. student’s thesis, would support an undergraduate research assistant, and serve as training for a post-doctoral fellow.