Water Resources Research Act Program

Details for Project ID 2016IL313B

Spatial and temporal modeling of road salts in a watershed with mixed, urban and agricultural, land use

Institute: Illinois
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $10,000 Total Non-Federal Funds: $24,780

Principal Investigators: Eric Peterson

Abstract: Within the Chicago Metropolitan area (CMA), streams have chloride (Cl-) concentrations that are temporally variable and elevated in response to deicing applications. Gradual increase in both winter and summer baseline stream Cl- concentrations is associated with steady buildup of Cl- in the system. No model currently exists to understand how Cl- varies temporally or spatially. The proposed project will develop a GIS model and fluid and solute model to determine the transport and fate of Cl-in a system by addressing three objectives: 1) Does road salt applications elevate Cl- concentrations in a stream throughout the year?; 2) Under what conditions will a watershed reach equilibrium between Cl- inputs and outputs; 3) What is the time interval required for a system to return to background levels of Cl- once inputs are decreased or ceased? Model development will focus on a smaller watershed, Little Kickapoo Creek (LKC), in central Illinois rather than the CMA. LKC watershed exhibits similar temporal Cl- patterns as observed in the CMA, but has not witnessed a sustained elevation of Cl-. LKC is also more accessible and provides simpler, fewer external variables, system to examine than CMA. LKC originates in an urban area and then transitions into an agricultural dominated area. Seven locations along LKC will be sampled every two weeks, with the water analyzed for major ions. The water chemistry data will be incorporated into a GIS to analyze for temporal and spatial trends related to deicing events. Additionally, a groundwater flow model coupled with a solute model will be developed to simulate Cl- transport and fate in response to various recharge and application conditions. The project will serve as a pilot for deployment to larger areas, i.e. CMA or Illinois River. The project will directly involve two graduate students from the Illinois State University Hydrogeology M.S. program and two undergraduate students with course experience in GIS. All students will be involved in the water sampling and analyses. The GIS models will be developed primarily by the undergraduate students, and the graduate students will focus on the flow and solute models.