News Release 380

Increased rainfall and flooding can lead to water quality concerns

Volume 38-380 (For Immediate Release)
Contact:  Renee Bungart

JEFFERSON CITY, MO, JUNE 25, 2010 – Heavy rainfall in the Midwest is causing flooding along the Missouri and Mississippi rivers and in other areas of the state. The Missouri Department of Natural Resources is continuing to work with local, state and federal responders to address flooding issues occurring across the state.

With increased rainfall in majority of the state, the department would like to remind Missourians to take precautions when applying fertilizers, pesticides and herbicides to their lawns, gardens and crops. Watch local weather forecasts before application and avoid applying if rain is in the forecast. Rain can wash chemicals into the local watershed, which could jeopardize local water quality.

As one example, the city of Maysville’s public water supply was recently found to have low levels of the herbicide atrazine. Public water supply systems are required to test their drinking water regularly. The three previous quarterly samples collected from the water supply did not detect atrazine in the water.  The city continues to meet the requirements of safe drinking water laws; as an extra precaution, the department is working with the city to address the levels. The excessive rainfall during the last few months could have been responsible for the increases in the chemical level.  Atrazine is a common herbicide used to control broadleaf and grassy weeds. 

The department is also working with wastewater treatment facilities as necessary to advise on possible wastewater bypassing from the flooding.  Facilities may need to bypass or shut down a treatment system or tributary sewer system where excessive storm drainage or runoff would damage any facilities or processes necessary for compliance with effluent limitations and conditions of a facility’s permit.  Facilities are required to take all reasonable measures to avoid a bypass or shutdown.  However, if one occurs a facility must notify the department by telephone within 24 hours and follow up with a written report with five days of all bypasses or shutdowns. 

Despite the summer heat, it is best for the public to not swim or wade in flooded waters as they can be contaminated with human and animal wastes or can include harmful contaminants. Use caution when recreational boating on rivers in flood stage. Rapidly flowing floodwaters can contain unpredictable currents, eddies and can conceal debris submerged or moving objects that can damage a boat.

The public should contact their local emergency response agency, the department’s Environmental Emergency Response section at 573-634-2436, or the department’s nearest regional office if they suspect a flooded body of water is contaminated with petroleum products or other chemicals.  Additional information on regional office locations and telephone numbers is available on the department’s website at