The Wisconsin Natural Resources Board yesterday adopted a proposed rule that imposes phosphorus limits for Wisconsin rivers, streams and lakes. The rule provides a two-pronged approach, by setting water quality standards and placing new limits on municipal wastewater treatment plants and factories that have their own treatment systems.

Under the rule, the DNR will impose numeric water quality criteria for phosphorus. Specifically, the rule limits phosphorus run-off from farm fields to six pounds per acre annually over an eight-year average. The rule also prohibits farmers from plowing within five feet of stream bank to prevent erosion. These requirements, however, would not be enforced upon farmers unless the State covers 70 percent of the compliance costs.

Perhaps the most restrictive and costly provision is a per-liter limit of phosphorus in Wisconsin waterways. For example, the rule provides that rivers cannot contain more than 100 micrograms per liter of phosphorus. Under the rule, municipal wastewater plants, food processors, paper mills and other factories are required to work with farmers to achieve these limits.

The rule is the most restrictive in the Midwest and will force businesses and municipalities bear the brunt of the costs. Complying the regulations range from $1.13 billion to $4 billion. Although the Natural Resources Board adopted the rule, it is still subject to legislative review, which could take place by the end of July. The DNR has until September 2010 to adopt the rule before the end of 2010.

To follow the phosphorus rulemaking process, click here.