Wisconsin’s Department of Natural Resources has approved new regulations to prevent manure from contaminating groundwater. The rules target a region including 15 counties and the city of Milwaukee. They're especially aimed at farms in the northeast, where cattle populations have increased and geological conditions allow manure to seep into groundwater supplies. Gov. Scott Walker, who must approve the regulations, said he’s “generally optimistic” about the rules, but said they still need review. Jennifer Giegerich, legislative director of the Wisconsin League of Conservation Voters, said the rules are a good first step, but she worries about their uncertain fate in the Republican-controlled Legislature. Paul Zimmerman, a lobbyist for the Wisconsin Farm Bureau Federation, said his group fully backs the rules. The Farm Bureau is "committed to get this rule package done this session. But we can't stop with passage here today. We need to get this implemented," Zimmerman told the Milwaukee Journal Sentinel.