Wisconsin’s revised rule to curb phosphorus pollution has been approved by the U.S. Environmental Protection Agency. In December 2010, Wisconsin became the first state in the country to adopt phosphorus water quality standards for lakes, reservoirs, rivers, and streams.

“EPA’s approval of Wisconsin’s phosphorus rule is a great step forward in our efforts to reduce phosphorus entering our lakes, rivers, and streams,” says Department of Natural Resources Secretary Cathy Stepp. “Using this rule, communities and businesses can work together to make meaningful phosphorus reductions.”

Phosphorus pollution fuels algae and plant growth. A comprehensive national analysis of nutrients in streams and groundwater from 1992 through 2004 shows that levels of phosphorus and nitrogen have stayed the same or increased since the 1990s despite major federal, state, and local efforts to control point and non-point sources and transport of these nutrients. A timeline showing efforts to reduce such pollutants is available online. Wisconsin began regulating some forms of phosphorus discharge as early as 1992 and had shown some early progress in phosphorus control.

Under the new rules DNR determines the phosphorus discharge limits based on the condition and quality of a watershed. Limits can vary depending on whether a waterway is already impaired by phosphorus, among other factors. DNR can include a compliance schedule in its Clean Water Act permits if phosphorus discharge limits are either new or more stringent than in the past. The rule also allows new flexibility while pollution controls are being put in place, depending on the watershed. For example, the rule and new state laws now allow for innovative nutrient trading programs including tools that allow for more of a holistic watershed approach.

“Wisconsin DNR will continue to work with EPA to ensure that we have the needed flexibility to implement the law in a manner that brings water quality improvements,” said Stepp.

EPA has the approved the rule as a revision to Wisconsin’s federally-approved National Pollutant Discharge Elimination System program under the Clean Water Act. For more information search for “phosphorus rules” on the DNR website.