Many of these 5.6 million acres were located in the fertile farmground of northern Indiana. Early in the 19th century, landowners began using open ditches and tiles to drain large areas of wetlands. They then converted the drained soil to agricultural pro- duction. Since then, nearly 86 percent of Indiana's wetlands have been drained or filled. Wetlands are areas characterized by saturated or nearly saturated soils most of the year.
Wetlands serve a number of important environmental functions.
Location, soil type, surface and ground water movement determine which of the following functions a particular wetland may serve. Flood Water Retention Usually located in depressions, wetlands receive surface runoff during storms. Water collects in these areas and contributes to stream flow when full or through ground water movement. Wetlands act as a holding area for large quantities of surface water which can be slowly released into a watershed. A one acre wetland, one foot deep, can hold approximately 330,000 gallons of water.