Ground Water & NPS

 Mad River NPS Project Background and Results

Background

    The Mad River Nonpoint Source (NPS) Project began as a request from the Top Of Ohio Resource Conservation & Development Project (RC&D) for a presentation about geology and hydrogeology of the Mad River watershed to a group of interested local residents. The turnout was small, but a subsequent presentation on the same subject generated greater interest. Further meetings were held that included major landowners in the valley and representatives of state agencies and local organizations. With strong local interest and agency involvement, the Mad River Steering Committee was formed. Chaired by a local landowner, the committee began defining problems in the watershed and generating a plan of action. All parties involved felt that a clear understanding of how the ground water/surface water system works would be a sensible first step. After discussion with staff members at the Ohio Department of Natural Resources (ODNR) and the Ohio Environmental Protection Agency (OEPA), ODNR Division of Water (DOW) submitted a proposal to OEPA for a Section 319 nonpoint source grant for fiscal year 1993.

Hydrologic System

    The study is now completed after over 2 years of research on the upper Mad River and its' tributaries. The effects of nonpoint source pollution on the Mad River watershed were assessed by defining the hydrologic system and investigating water quality variations within the watershed. The study focused on understanding the interaction between ground water and surface water. Ground water levels were recorded during a series of quarterly surveys of 64 domestic water wells. Water table maps were constructed which showed the direction of ground water flow is toward the Mad River and its' tributaries.

    Ground water quality data shows certain wells consistently approach or exceed the safe drinking water standard of 10 milligrams per liter (mg/L) for nitrate. These high nitrate levels are concentrated mainly in the Kings Creek subwatershed, where the mean nitrate concentration is nearly 5.0 mg/L.

    Major ion analysis of ground water reveals a calcium-magnesium bicarbonate water type. Both ground water and surface water in the study area have this baseline water chemistry. Total dissolved solids (TDS) range from 125 to 665 mg/L similar to other buried valley setting in Ohio.

    DRASTIC ground water pollution potential mapping was used to identify areas in which sensitive land use activities would be inappropriate. Results of this phase of the study have identified ground water recharge zones in many outwash terraces located adjacent to the Mad River and its' tributaries.

River Hydrology

    During low flow condition on the river a large percentage of the surface water flow is being provided by ground water recharge. Hydrograph separation and gain/loss studies for all tributaries of the river shows a median percent of annual total streamflow due to base flow at 76.1 percent near Urbana (Koltun, 1995). A HEC-1 model of ground water recharge and its' effect on surface water flow has helped determine the best times for the application of agricultural chemicals in sensitive ground water recharge areas. The results of this portion of the study strongly support careful land use planning.

Summary

    Complete copies of the final report are available for viewing at the county extension and soil and water offices in Champaign and Logan Counties or from Ohio Department of Natural Resources, Division of Water. If you have any questions on the study or how to protect water quality in your home or town, please contact: