Projects
Water Quality and Karst Hydrogeology of Spring Mill Lake Drainage Basin
 |
Shaded relief map of Spring Mill State Park drainage basin. |
Project Overview
This investigation examines the contamination risk to the Spring Mill Lake drainage basin from nonpoint-source (NPS) pollution. Nonpoint-source pollution comes from many sources and is caused by rainfall or snow meltwater moving over and through the ground. As the runoff moves, it picks up and carries away natural and human-made pollutants, eventually depositing them in lakes, rivers, wetlands, and even underground sources of drinking water. These pollutants include excess pesticides from agricultural lands and residential areas; oil, grease, and toxic chemicals from urban runoff; sediment from improperly managed construction sites, crop and forest lands, and eroding stream banks; salt from roads; and bacteria and nutrients from animal wastes and faulty septic systems.
The Spring Mill Lake watershed is located in the Mitchell Plateau physiographic region, a karst area developed on limestones and dolostones in south-central Indiana. Potential NPS pollution is a problem in karst regions because karst aquifers are poor filters, and therefore, are highly susceptible to contamination. As is typical in karst terrain, the drainage divides are poorly defined and almost all runoff is diverted to subsurface channels. Within Spring Mill State Park, ground water from these subsurface channels comes out at several natural springs and then flows in surface streams to Spring Mill Lake. Spring Mill Lake is a reservoir built in the late 1930s. Both the recreational and aesthetic value of the reservoir have steadily deteriorated since it was completed, largely due to sediment accumulation, which is filling up the lake. Because it is shallow, much of the lake is in the “photic zone,” the region in which light intensity is adequate for photosynthesis and plant growth. Periodically, aquatic plants and algae growth greatly increases which may be caused by nutrient loading from agricultural land runoff in the watershed. |
|
This project, which began in 1998, was designed to determine contamination levels of the Spring Mill Lake drainage basin. Dye trace investigations in which nontoxic dyes are used to trace subsurface drainage routes were used to further divide the drainage basin into subwatersheds, and water samples collected at eight sites within the park for two years were analyzed. In addition, water samples were collected at two major discharge points within the park during a storm event in February 2000. Researchers analyzed the water samples to determine the suspended solids, specific conductance, temperature, field pH, dissolved oxygen, coliform bacteria, pesticides content, major ion chemistry, and trace element content.
As a part of the project a geographic information system (GIS) database was prepared that incorporates data from the Spring Mill Lake drainage basin, including information about roads, railroads, streams, and property boundaries. Information relating to land use was also compiled and used to estimate the pesticide application rates in the watershed.
More information:
|
Discharge and Precipitation| 1 of 8 |  next |
Geology | GIS/Maps | About Us | Bookstore | Interactive Maps | Licensing
IGSInfo@indiana.edu / 812-855-7636
Accessibility Information
Copyright, Map Disclaimer, and Limitation of Warranties and Liability