This is a paper I wrote for one of my environmental science classes a few months ago regarding Decatur’s water issues. I got an A on it! It had a different title though.
From the beginning of the city’s history, the Sangamon River in Central Illinois provided most of Decatur’s water needs. However, it didn’t take long for city leaders to realize that more water would be needed as the city grew. Smaller dams were created in the late 1800s to contain water but it wasn’t until 1922 that Lake Decatur was constructed to supply water to the expanding A.E. Staley Company. (Lake Decatur Watershed Protection)
The rich, black, fertile soil that supports such successful crops in the region is susceptible to erosion, due to the large amounts of exposed soil. 87 percent of the 925 square miles that comprises the Upper Sangamon River Watershed, which feeds Lake Decatur, is devoted to row crops. (Lake Decatur Watershed Protection) Some of the soil that enters the watershed is then deposited into the basins of Lake Decatur.
To combat this, city leaders have proposed different ideas throughout the years. In the early 1950s it was decided that dredging would be too expensive and impractical and that a new reservoir should be created. (Lake Decatur Watershed Protection) A name for this new lake was even given, Lake Springer. It was to be constructed northeast of the city. However this solution was never implemented due mainly to political obstacles and government regulations. Other reservoirs were suggested at other times. In fact, as late as 2008 the city pursued creating a second lake to support the water needs of Archer Daniels Midland Company. A partnership between the city and ADM would fund its construction. However, this project never came to fruition either, again primarily due to political reasons.
Without a major secondary source of water, dredging Lake Decatur, and tapping into nearby wells, became the only viable options, which would not face such fierce political opposition. Dredging Lake Decatur has long been discussed by many city councils. However, the costs and complexity of dredging the lake has often put the topic on the back burner. Securing a location to deposit the removed silt was also problematic for environmental, political and economic reasons.
In 1984, the Lake Decatur Sedimentation Control Committee recommended “steps to preserve the lake’s life.” Three feet of sediment had settled on the lake bottom, decreasing the lake’s holding capacity considerably. The committee also recommended creating sediment traps and encouraging soil conservation practices in the watershed area.
Dredging work has gone on in spurts since the 1980s to varying degrees of success, however the drought of 2012 made it very clear that the city needed to be far more aggressive in its dredging efforts. The most severe water restrictions in the city’s history were put into place in the summer of 2012. Lake levels dropped exposing the lake bottom in several of its more shallow basins. Practical solutions to find additional water were sought but none would meet the city’s needs if the drought had continued.
In the spring of 2013, the Decatur city council approved a large water rate increase to aggressively dredge Lake Decatur, as well as repair and replace aging water mains throughout the city. Additional emergency wells are also being drilled in the case of another severe drought.
While water quantity has been discussed, it is also important to discuss water quality. Being located in a heavily farmed state, Lake Decatur not only is threatened by soil erosion but also chemicals that are applied to farm fields that are then washed into streams. In the early 1990’s high nitrates made Decatur’s water unsafe for pregnant women and the state required that the city implement a system to remove high nitrates from drinking water. Today the nitrate levels are within safe limits, however it remains costly to keep nitrate levels at an acceptable number.
The 2011 water report shows that the city’s drinking water is in compliance with safe drinking water standards for all of the substances sampled. Most of the contaminants found originated from soil runoff such as atrazine and nitrate. Sulfate was also detected and much of it originates from industrial wastes. Overall, the report shows that the drinking water in Decatur is safe, according to the Illinois EPA. (2012 Water Quality Report)
If Lake Decatur is to remain a reliable water source for the city, dredging will have to be an ongoing process, as all lakes fill with sediment, if nothing is done to stop it. Along with dredging, good watershed management is also essential. It is far less costly to prevent soil runoff in the first place than it is to remove sediment from the bottom of a lake or filter contaminants out of drinking water. Because of better farming practices and better watershed management, less sediment flows into the lake today. The economic benefits of good soil conservation are obvious. “For every $1.00 spent by the City of Decatur, (on soil conservation), the City benefited $4.14.” (Lake Decatur Watershed Protection)
2012 Water Quality Report. City of Decatur. 2012. Web. 3 May 2013.
Lake Decatur Watershed Protection, Celebrating Lake Decatur’s 80+ Birthday and The Urban/Rural Partnership to Protect It. Web. 3 May 2013.