Lake Mauvaise Terre Streambank Erosion & In-lake Dam Assessment

Project Description


Lake Mauvaise Terre is located in Morgan County, Illinois and is a water supply for the City of Jacksonville.  It is impaired for numerous constituents, including phosphorus and sediment.  To compliment recent work on a Watershed Implementation Plan, Northwater was retained by the American Farmland Trust (AFT) and the city to perform a reach level assessment of watershed streambank erosion and to evaluate the potential for construction of a new in-lake/low-flow sediment dam.

Northwater surveyed over 13 miles of streams to quantify lake sediment and nutrient loads associated with bank erosion and to identify potential project locations.  It was determined that an in-lake/low flow dam to trap sediment is feasible and that that streambank erosion is responsible for 12% of the total watershed sediment load.  Northwater concluded that efforts to limit sediment loading from upland areas would result in much greater benefits to water quality.  Project recommendations and a map atlas representing results of the stream survey were developed.  The entire project was completed on time under a very aggressive schedule.

Read more about the watershed plan and implementation…

Lake Mauvaise Terre Watershed Implementation Plan

Lake Mauvaise Terre Nutrient Reduction Initiative – Plan Implementation & Construction

The AFT has been working with Northwater since 2014 and have been impressed with their work ethic and technical watershed management expertise. This prompted us to engage Northwater to build a water quality model to support our initiates in the Upper Macoupin Creek watershed. After researching other water quality models, we determined that their SWAMM system was the most applicable to our project needs. We are utilizing it to determine cropland areas where in-field management measures, precision outreach, and conservation practices will have the greatest impact on improving water quality. The model has quickly become a reliable tool to support our ongoing efforts. The staff at Northwater are a pleasure to work with and we will continue to engage them to support other AFT initiatives in the Midwest.

- Kris Reynolds, Midwest Deputy Director, American Farmland Trust

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