(Iowa News Service) The Iowa Department of Natural Resources is updating the rules defining how manure is stored at animal feeding operations.

For generations, groundwater has been threatened by soil runoff from these operations, and environmental advocates want to see tougher standards. Farmers routinely apply the manure to their land as fertilizer. But erosion, unpredictable weather and rules that are difficult to enforce leave the manure contaminating ground and surface water.

Michael Schmidt, staff attorney for the Iowa Environmental Council, is calling for greater separation between manure storage facilities and karst soil, which contains porous rock, limestone and underground caves.

"And if you build a manure storage structure on top of that, it can basically all run into those caves and get into the groundwater and the surface waters," Schmidt explained.

The DNR said despite its existing rules, there are still hundreds of streams, lakes and private wells teeming with high levels of fecal coliform and other pollutants.

Schmidt pointed out the environmental council is also asking the DNR to modernize manure management plans for farmers, so they are an up-to-date reflection of what is happening on their land. Right now, plans are submitted on paper, which Schmidt argued means a less than accurate account of what really takes place at confinements across the state.

"We have roughly 9,000 animal feeding operations in Iowa," Schmidt noted. "And so, it is an overwhelming task to try to provide oversight for all of these. And having the contents be electronic and geospatial would let DNR and the public have a much better sense of where the manure should be applied and how much should be applied."

The DNR plans to hold a public hearing on its proposed new rules at the end of September.