A buffer strip of grass and trees along the Rock River west of Edgerton is a good example of the protective strips that help filter runoff. (The Minnesota Star Tribune)

The Senate unanimously passed a measure Thursday that would alter a contentious clean water bill that passed in 2015 but caused consternation among some landowners.

The House is likely to take up the measure next week, when it is expected to face some opposition.

The 2015 bill, which was the subject of months of negotiation between DFL Gov. Mark Dayton and House Republicans, sought to create buffer zones around waterways to prevent farm pollution from contaminating the state's water.

Almost immediately after passage, House Republicans began attacking the Dayton administration for applying the law too broadly, including buffers around private ditches.

Dayton capitulated on the private ditch issue and ordered state agencies to apply the law to public waterways only, but he also warned the Legislature not to weaken the law's effort to protect waterways.

The governor plans to sign the measure when it reaches his desk, saying it provides greater certainty for landowners and gives local officials better tools for enforcement.

"More and more citizens and communities throughout Minnesota are being threatened by water that is unsafe for their drinking, washing, and recreation," Dayton said in a statement. "These water quality problems must be addressed by all of us recognizing our shared need for safe and clean water, and our by shared willingness to protect this priceless resource."

The bill currently making its way through the Legislature, which has again been the subject of intense negotiation with conservation groups, would codify Dayton's ruling on private ditches and clarify language on other provisions.

The buffer requirement around waterways has long been in state law but was left unenforced by many local governments. The new law makes it easier to administer the regulations, provides incentives for local government to step up enforcement and gives significant oversight to the Board of Soil and Water Resources.

Trevor Russell, water program director for Friends of the Mississippi River, said groups like his did not ask for changes to the law this year but are satisfied that most of the changes are merely clarification.

This year's bill will likely face opposition in the House when it comes before the lower chamber as soon as next week. Environment-minded DFLers believe it does not do enough to protect water quality, while some Republicans see it as an intrusion of property rights.

J. Patrick Coolican • 651-925-5042