Water sources can become contaminated after prolonged flooding issues

Flooding creates many problems for farmers and homeowners, one of which is water quality.

Flooding can cause bacteria and contaminants to enter wells and water supplies and render them unsafe to drink from for humans and livestock.

Wells that have been submerged beneath floodwater or high groundwater tables should be disinfected and tested for safety before using water from them for drinking or food preparation, according to Iowa State University Extension. Most wells do not have watertight caps, so bacteria, silt and other pollutants are likely to enter them if they are submerged. Wells located near streams or drainage ditches are particularly vulnerable to flooding following rapid snowmelt or heavy rainfall, but wells located away from surface water also can become submerged if they are located inside leaky frost pits that become flooded as shallow water tables rise during wet seasons.

A water-quality issue some farmers might be facing is potential contamination of water supplies or creeks, rivers, etc., from manure lagoons. The Missouri Department of Natural Resources has a publication on its website that covers minimizing damage in these situations.

According to the University of Missouri Extension, if manure storage is about to overflow, it is better to land-apply manure under poor conditions than to have a storage spill directly to a creek or other body of water.

If applying under emergency conditions, be sure to apply at low rates onto land that has cover (e.g. pasture and hay ground). Maintain separation distances between application area and sensitive features. Apply on areas with low slope that are not prone to flooding. Rigorously monitor the area during land application to ensure no manure is running off the field. Keeping records to document extreme weather affecting your farm and your application practices is highly recommended. If manure from an overflow of storage or from land application on wet ground leaves your property or reaches a stream or other body of water, you are required to report the spill to your regional Missouri Department of Natural Resources office.

If a producer’s well or water supply has been subject to flooding (or even suspected flooding), the well should be disinfected via a process called shock chlorination. A well driller or savvy producers can treat wells this way. After the well has been shocked, a water sample will need to be taken and tested to ensure there are no traces of coliform bacteria and that it is safe to drink.

For livestock, contaminated water supplies are also a concern. The University of Nebraska-Lincoln stated the concern with grazing pasture is any standing water available could be consumed. If livestock has access to fresh water, the risk of toxicity would be lowered and thus providing fresh water access is recommended. However, testing the standing water is a good risk management strategy. If standing water is the sole water source for livestock, then sampling of the water is highly recommended because the risk of cattle consuming toxins or coliforms is increased. In general, cattle tolerate high coliform concentrations in drinking water without any effect on production or reproduction. Thus the major issues, in terms of cattle health, would be related to nitrates or chemicals.”

Producers with potentially compromised water sources should reach out to their area extension and health department professionals to navigate through these issues.


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