Environmental Problems/Issues
Flooding
Flooding results during periods of heavy rainfall or during a late winter or spring snow thaw, when streams and rivers bank can not contain the increased water flow. Missouri River flooding was controlled by building the dam project at four places along it's course. However, smaller rivers do not have luxury of dam construction, so farmers and ranchers must endure the flooding and hope that the river will recede as quickly as possible.
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Ground Water Pollution
Some locations around lakes and reservoirs and over shallow water aquifers in eastern South Dakota encumber great risk for ground water pollution since they are sources for drinking water. Excessive fertilizer and manure applications, or improper application of agrochemicals can threaten this drinking water source. Local Water Conservation Districts place warning signs in certain locations where restrictions of agrochemicals use and farming activity may be legally enforced to safeguard the water supply for the local population.
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Sedimentation
Erosion of stream banks and rivers introduce sediments into reservoirs which is trapped and settles into the reservoir. Sediment from erosion-prone soils of central and western South Dakota and northern Nebraska moves into regional drainage basins and ultimately into the Missouri River reservoirs. Since the 1960's when dam construction was completed, the cumulative reservoir capacity has been reduced 5-25%. If aggressive erosion controls are not implemented soon, reservoirs will continue to fill with sediments. Flooding again will threaten agricultural land, towns, and cities especially along the western parts of Lewis and Clark Lake and Lake Sharpe. Electricity production may be curtailed as well.
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