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About the Maple River |
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The Maple River flows from Penny Lake in northwestern Freeborn County and initially follows a generally northwestward course through northeastern Faribault and southern Blue Earth Counties. It turns northward in Blue Earth County and passes the town of Good Thunder. It joins the Le Sueur River from the south, about 6 mi (10 km) south of Mankato. [Source ~ Wikipedia.com]
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Water Quality Problems |
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The land in and around the Le Sueur River Watershed has many positive aspects including; its aesthetic value, its vast populations of migratory waterfowl and game fish. In addition, surface and groundwater deposits provide drinking water for several rural communities. Unfortunately, the extent of all the benefits is outweighed by the fact that several rivers in the watershed including the Maple have poor water quality caused by several different limiting factors including the following:
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Fecal Coliform Bacteria - A group of bacteria found in the intestinal tract of humans and animals, and also found in soil. While harmless in themselves, coliform bacteria are commonly used as indicators of the presence of pathogenic organisms and other disease-causing bacteria |
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Sedimentation - causes turbidity in the water that limits light penetration and prohibits healthy plant growth on the river bed. Sediment also can cover much of the river bed with a blanket of silt that smothers life. |
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Phosphorus - is an essential nutrient for plant growth. Excess levels of this nutrient can cause algae to bloom in lakes and rivers, which has direct and secondary impacts on water quality. |
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Nitrate-Nitrogen - loading in the Le Sueur River Basin has both local and national implications. At times, some communities in the basin have experienced elevated nitrates in their drinking water. Further downstream, Nitrate-Nitrogen from the Mississippi River Basin has been identified as one of the major causes for the expanding area of low dissolved oxygen or hypoxia zone in the Gulf of Mexico. |
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Hydrologic Modification, in addition to water quality, also is a concern that limits the beneficial uses of rivers and streams within the Minnesota River basin. Chronic annual floods can downcut and widen streams, damage property and place severe stress on communities and individual residents of the floodplain. Typically, those living in the lower reaches of the watershed may be economically impacted by extensive drainage up the watershed. |
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Downstream Impacts |
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Because of water's ability to flow naturally in lakes, rivers, and streams they do not follow judicial boundaries such as county lines and state boarders. Because of this, our actions here in the Maple River watershed can affect other bodies of water in our county, state, and nation. |
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An example of this is happening in Lake Pepin. Lake Pepin is experiencing 2 problems increased sediment and increased phosphorus levels. When the Mississippi enters Lake Pepin, it slows down and drops much of the sand and silt that it is carrying; phosphorus attaches to the sediment that separate out of the water. The increased levels of phosphorus and sediment can lead to excessive algal growth particularly in dry low-flow years which can cause low oxygen levels and localized fish kills. It has been estimated that 80% of the sediment entering Lake Pepin is originating from the Minnesota River Basin and its vast farming communities. Further down stream the Gulf of Mexico has an ever expanding area of low dissolved oxygen or the Hypoxic Zone. Each summer the nutrients carried into the gulf by the Mississippi River support large algal blooms. When algae die and decompose they use a majority of the dissolved oxygen in the water and as a result create an area where marine life cannot survive. The Minnesota River has been identified as one of several high contributors of nitrogen into the Mississippi River. |
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