Minnesota and Wisconsin Draft TMDL for St. Croix River

Environmental officials from Wisconsin and Minnesota have been working on a plan to improve water quality in Lake St. Croix, the final 25 miles of the nationally designated wild and scenic St. Croix River.

An open-house public informational meeting on the project will begin at 6 p.m. on Jan. 11. It is jointly hosted by the Wisconsin Department of Natural Resources and the Minnesota Pollution Control Agency.

A draft TMDL report will be presented and explained beginning at 6:30 p.m. This stands for “total maximum daily load,” a scientific determination of how much of any given pollutant a water body can absorb while still meeting water quality standards for aquatic life and human recreation.

Because Lake St. Croix can no longer meet these standards, it was placed on the federal list of impaired waters in 2008, requiring the states to take action. The primary problem is excessive levels of phosphorus and other nutrients that enter the river as runoff from agricultural fields and barnyards and from urban storm water and wastewater discharges.

Phosphorus fuels blue-green algae blooms, which can be toxic to animals and humans, causing respiratory ailments, watery eyes and rashes. Excessive phosphorus and algae blooms can lower dissolved oxygen levels in the river, harm aquatic life and cause fish kills.

In 1968, the St. Croix National Scenic Riverway, along with its major tributary, the Namekagon River, was established as one of the original eight rivers under the national Wild and Scenic Rivers Act. In 1972, the lower 52 miles of the St. Croix River were added to the system.

Both Wisconsin and Minnesota have designated the St. Croix River as “outstanding resource water,” a designation that recognizes the river’s importance and, within the laws of each state, establishes restrictions on discharges into the river.

The states have joined as partners with civic groups in the St. Croix River basin to develop a comprehensive plan to reduce phosphorus flows and improve the water quality of Lake St. Croix.

The preliminary TMDL report contains information about regulatory and non-regulatory reductions in phosphorus levels necessary to restore Lake St. Croix. The preliminary report is available at www.pca.state.mn.us/publications/wq-iw6-04b.pdf.

Source: Media Newswire