A proposal to greatly expand the feder­al government’s auth­ority to regulate waterways will negatively affect farmers’ livestock and crop operations as well as their conservation efforts, members of the Iowa Farm Bureau Federation’s (IFBF) 2014 Ag Leaders class told lawmakers last week in Washington, D.C.

The Environmental Protection Agency (EPA) and Army Corps of Engineers earlier this year issued a revised definition of "waters of the U.S." (WOTUS), describing what waters can be...