Wise Water Words - Volume 52, Issue 1 (Spring 2015)
Nitrates
(Submitted by David Lathrop - Nebraska Department of Environmental Quality)Recently, two water systems have come to my attention both having to deal with high nitrates in their source of drinking water. In both cases, non-point source pollution originating predominantly from agricultural activities have polluted their drinking source water.
In the first case, the City of Hastings has been collaborating with the two local Natural Resource Districts (NRDs) in its area to encourage best agricultural practices such as fertilizer application training, deep soil samples, scheduled irrigation, and reporting to reduce nitrate contamination.
While these strategies are making improvements, the lag time from the travel from the nitrate application sites to the Hastings drinking source water wells is long. Furthermore, reversing the nitrate concentrations is a slow process. As a last resort, Hastings has embarked on a bold and innovative treatment system that will pump groundwater out of the aquifer, remove the nitrates and pump it back into the aquifer upstream of the city's drinking-water wells. The project which is to be built in phases is expected to cost over $45 million and will benefit 25,000 residents and businesses of Hastings, and possibly outlying communities. The first phase construction is planned for completion in the summer of 2015.
By contrast, much of the source water for Des Moines (Iowa) comes from the Raccoon River, which is fed by aquifer water and storm water runoff into the river. If nitrate level trends in the river do not reverse, the Des Moines Water Works will need to invest $80 to $100 million into its drinking water treatment process.
An Iowa Commission was formed to make recommendations to address the nitrate problem in the city's drinking source water. In May 2013, the Commission created a strategy of voluntary compliance with no monitoring requirements. Fast forward to now, and nitrate concentrations in the Raccoon River continue to increase. With the health of 500,000 population to protect, the water works' governing board voted on January 8th to sue three northwest Iowa counties for their role in creating non-point-source pollution.
Fortunately, most of the best practices to reduce nitrate contamination are also the best business practices for adding to the bottom line of agricultural operations. However, there are no short-term fixes for reducing nitrate contamination. Nature has to take its course. On the other hand, the long term outlook is good, especially if communities and ag producers work together. In both cases, the nitrate contamination problem will be "fixed". It just a matter of when the fix will be started, where the fix will be done, who does the fixing and who does the paying.
