Water Resources Research Act Program

Details for Project ID 2015OH453B

Spatial and Temporal Dynamics of Non-Point Source Pollution

Institute: Ohio
Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-29
Total Federal Funds: $35,217 Total Non-Federal Funds: $35,416

Principal Investigators: Gajan Sivandran

Project Summary: Despite extensive and increasing investment by the USDA since 1987, agricultural non-point source (NPS) pollution remains the leading cause of water quality problems in the United States and a serious concern for policy makers, scientists, and the residents who rely on impacted waters. The Upper Big Walnut Creek (UBWC) watershed in central Ohio provides drinking water for approximately 600,000 residents of Columbus and surrounding communities. The majority of headwater streams in this watershed are impaired by nutrient enrichment, pathogens, and habitat degradation stemming from agricultural management practices. Existing pressures on the watershed may also be exacerbated by local impacts of global climate change. Global climate change is predicted to increase climate variability, altering the distribution of environmental variables that influence agricultural and hydrological processes (e.g. longer growing seasons, more frequent extreme precipitation events, and increasing periods between events). Under an uncertain climate future, it is critical to understand how all linked processes—biogeochemical, hydrological, and land management—could accelerate and exacerbate the impacts of NPS pollution in the UBWC Watershed. The overarching goal of this research is to identify the hydrologic and land surface characteristics that influence the spatial and temporal dynamics of NPS pollutants (nitrogen and phosphorus, in particular). To achieve this objective the following activities will be undertaken for the UBWC watershed: (i) Assessment of a suite of existing indexing methods used to identify critical source areas (CSAs); (ii) Application of the Soil and Water Analysis Tool (SWAT) to quantify pollutant load for comparison of SWAT derived CSAs to those identified by existing methods; (iii) Application downscaling techniques of climate change scenarios in order to extract the climate parameters necessary to force the SWAT model for future scenarios; and (iv) Comparison of SWAT derived CSAs generated under historical and future hydrologic conditions. By developing relationships that link hydrologic, biogeochemical and land management characteristics to the spatial and temporal dynamics of NPS pollutants, the identification of chronic and acute CSAs will be achieved for the UBWC watershed. This methodology is generalizable and applicable to any agricultural based watershed with NPS pollution issues. The CSAs developed by this research will aid water resource managers by providing a method to prioritize the deployment of conservation measures and monitoring equipment.