Restoration Plan for Little Storm Lake

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Serpentine Sediment Basin: Newly created channel for water entering the west side of the marsh. As water is slowed by the twisting channel, sediment will drop from the water and be deposited here where it can occasionally be removed.

High Flow Spillways: When heavy rainfall brings large amounts of water from the watershed, the spillways allow the water to equalize on both sides of the dike and preserve the water capacity of the area.

Diversion Dike: Built during the winter and spring of 2012, this large earthen structure will allow dewatering during drier periods. Consolidation of the sediment and re-vegetation of the area will produce higher quality water entering Storm Lake during normal flow conditions. The dike will also prohibit carp and other rough fish from entering the basin.

Dewatering Pump and Sediment Basin: This pump can be used to draw down water in the large basin in an effort to consolidate or compact the sediment and get aquatic vegetation to grow on the unstable muck covering this entire surface. Such vegetation will cause more sediment to be deposited here rather than being carried into Storm Lake. It also acts to break down many chemical substances in the water. During pumping, the water will be pumped into the sediment basin to allow any sediment to settle out before it enters into Storm Lake.

Pump Outlet: At times when vegetation is growing across the basin floor, the water will flow by gravity through the pump outlet under the dike to the outside of the dike and into Storm Lake.

Three Water Flow Conditions
Normal Flow: Newly created channel for water entering the west side of the marsh. As water is slowed by the twisting channel, sediment will drop from the water and be deposited here where it can occasionally be removed.

Draw Down: Water will pass through the serpentine channel and along the west side of the dike into Storm Lake. Sediment will fall from incoming current as the water slows.

Heavy Flow: Water will flow into the basin created by the dike. The water can enter the area through the normal means or may overflow into the basin through the spillway. Once it has filled the basin, it will overflow the dike and move into Storm Lake. Under extreme flow, the dike may be underwater.

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Main Project Goals
  • Reduce sediment and nutrient transfer into Storm Lake
  • Remove/control the rough fish population
  • Consolidate sediment in the little lake
  • Re-establish a diverse vegetation community
  • No adverse impact to adjacent landowners
Secondary Goals
  • Efficient water level management on the little lake
  • Sediment basins that can be easily cleaned and maintained
References
For more information, please see:
Iowa DNR plans for restoration, p. 17
Iowa Environmental Focus
http://iowaenvironmentalfocus.org/2011/02/15/storm-lake-restoration-should-improve-water-quality/