Soils provide five primary functions . Most people are aware that they provide a medium for plant growth, serve as a material on which we build our homes and businesses, provide a habitat for some forms of animals and organisms, and contribute to our domestic water supplies. Two of their lesser known benefits are that they recycle nutrients and organic wastes and they help purify our water supplies by removing pollutants from surface water runoff and groundwater as it moves through the soil. As water percolates through the soil some pollutants are attached to soil particles. Pollutants, depending on their type and characteristics, may then be removed by plants, most of which depend on soil for growth and survival, through root absorption and plant uptake
Soils, if not properly managed and protected from erosive forces, can also have a negative impact on water quality. Sediment is eroded and transported mostly during heavy rainfall events and the associated high streamflows, particularly floods. Sediment can become a problem because its deposition in streams and lakes can ruin the habitat for aquatic plants and animals. It can also fill stream channels, lakes, and harbors, which then require costly dredging. Studies have shown that the amount of suspended sediment in surface-water bodies can be related to natural factors such as soil type and geology. In general, however, the most important factor for sediment transport is the amount of land cleared of vegetation. Sediment sources typically are lacking in developed areas, but during tillage or construction, when little vegetative cover or pavement exists, the exposed soil can be easily eroded during storms and deposited in downstream waterways. Sediment in rivers and lakes is a concern because many contaminants can attach and move with the sediment particles. (Source: http://www.waterenclyclopedia.com/La-Mi/land-Use-and-Water-Quality.html#oxzz2YqVSKeol)
The Iroquois Watershed consists of several soil types. Soils in the southern portion of the watershed, predominantly south of Indiana State Road 14, formed under prairie/grassland conditions whereas the soils in the northern part of the watershed were influenced by forested and savannah conditions. In general the soils in the watershed can be characterized as deep to very deep, nearly level to strongly sloping, very poorly drained to moderately well drained, fine to medium textured soils on upland glacial till plains and moraines. Soils in the watershed are generally well suited for agricultural production when drained. The main management concerns are wetness, ponding, flooding and erosion. The Natural Resources Conservation Service has several conservation management practices in the arsenal of tools they use to combat and prevent erosion. Some key conservation practices they use to prevent soil erosion are shown in the picture above.