Staff in the Iowa Department of Natural Resources have drafted tougher rules for manure storage at any new livestock confinements or cattle feedlots in parts of northeast Iowa.

The regulations would apply in areas with what’s called “karst” topography, where the bedrock is closer to the surface and it can be porous. Under current rules for these areas, manure from livestock operations must be stored in concrete structures. If the changes are adopted, the distance from the concrete bottom of any new manure pit and the bedrock would have to triple from at least five feet to 15 feet.

In addition, there would have to be a layer of clay soil or some kind of protective material between the bedrock and the concrete floor of the manure pit above.

Eldon McAfee, an attorney who represents the Iowa Pork Producers and the Iowa Cattlemen’s Association, says the groups believe the current rules sufficiently protect groundwater and the changes could end expansion of livestock operations in northeast Iowa.

“We could have producers who can’t build livestock operations with concrete manure storage on their farms,” McAfee says, “and that is very important to that area.”

More than a dozen environmental groups say the proposed changes don’t go far enough.

“We are calling on DNR to do a better job regulating all of this manure to reduce the nitrogen, phosphorus and bacteria that enters our drinking water sources, our groundwater, our lakes, rivers and streams,” says Michael Schmidt, a staff attorney with the Iowa Environmental Council.

The DNR is accepting informal comments on the proposed changes until late Friday afternoon. After that, there’s a formal public comment period and a possible rewrite of the rules. The Iowa Environmental Protection Commission has to vote on any changes, then a committee in the legislature either approves or blocks the regulations.