On February 6, 2017, the U.S. Environmental Protection Agency (EPA) approved Wisconsin’s Multi-Discharger Variance (MDV) for Total Phosphorous. The MDV establishes an additional and less-costly compliance option for eligible point sources seeking relief from burdensome phosphorous discharge limitations. The EPA’s approval of the MDV will last for a period of 10 years, but may be extended if the Wisconsin Department of Natural Resources (WDNR) requests and receives an extension. In a draft version of its MDV Justification submission for the EPA, WDNR indicated that an extension will likely be necessary.

Phosphorous Standard

In 2010, the WDNR promulgated rules creating a phosphorous standard intended to reduce the amount of phosphorous entering the state’s watersheds. Following approval by the EPA, those rules became the federally enforceable water quality standard upon which discharge limits for point sources are calculated. Complying with the new discharge standards proved to be an exceedingly difficult challenge, and many facilities sought approval for individual variances. As the number of facilities seeking variances increased, the state sought to streamline the process, which resulted in the development and passage of 2013 Wis Act 378. 

Act 378, which became effective in 2014, directed the WDNR and the Wisconsin Department of Administration to investigate the costs associated with attaining the water quality standard for phosphorous and its impact on the state’s economy. That study revealed that compliance with the phosphorous standard would result in “substantial and widespread adverse social and economic impacts to the state,” prompting WDNR to request EPA approval for this MDV.

Compliance Options

The MDV extends the timeline under which point sources must comply with phosphorous limits, including those based on a federally approved total maximum daily load (TMDL). To be eligible to apply for an MDV, a point source must be an existing facility that would require a major facility upgrade to comply with its phosphorous water quality-based effluent limitations (WQBEL). If a facility meets the eligibility criteria and requests an MDV, the facility’s Wisconsin Pollution Discharge Elimination System (WPDES) permit will, upon approval, be modified or reissued with two important conditions. First, each point source must reduce its phosphorous load each five-year permit term. The final MDV approved by the EPA includes the following default limitations for each permit period:

• Permit term 1: 0.8 milligrams per liter (mg/L)

• Permit term 2: 0.6 mg/L

• Permit term 3: 0.5 mg/L

• Permit term 4: Phosphorus WQBEL

These default limitations may be adjusted if attainment is not feasible. Moreover, every five years the WDNR will review these interim phosphorous limitations to determine whether they are consistent with the highest attainable condition for the point sources and categories of point sources that are eligible for the variance.

A point source receiving an MDV must also implement a watershed improvement project to help reduce nonpoint source phosphorous pollution. These projects must include a binding, written agreement with either WDNR or other third parties to offset the amount of phosphorous by which the point source’s discharge exceeds the target value. If a point source is located in a watershed for which a TMDL has been approved, its target value is the phosphorous discharge limitation included in its WPDES permit pursuant to the TMDL. If the point source is located in a watershed not subject to a TMDL, the target value is .02 mg/L. Alternatively, a point source may elect to pay its county Land Conservation Department $50 per pound of phosphorous discharged in excess of the target value. The per pound payment will be adjusted annually in proportion to any changes in the U.S. consumer price index for urban consumers. However, the per pound payment in effect when the permit is issued will apply for the full permit term.