Contact: Cathy Rofshus, 507-206-2608
St. Paul, Minn. -- The Minnesota Pollution Control Agency today announced a public comment period will begin Feb. 8 and continue through March 26 on a water quality standard proposed for the south metro Mississippi River. The public is encouraged to attend meetings on the standard on Feb. 11, from 2 p.m. - 7 p.m., at the University of Minnesota Southern Research and Outreach Center in Waseca, and on Feb. 23, from 2 p.m. - 7 p.m., at the St. James Hotel in Red Wing.
The MPCA is conducting a pollution study of this reach of the Mississippi River. It is called a Total Maximum Daily Load (TMDL) study and includes setting a water quality standard specifically for this stretch of the river. The MPCA is proposing this specific standard because existing standards are not designed to protect the unique aquatic ecosystem of this part of the river.
The proposed standard is an integral part of the pollution study, which will be finalized after the U.S. Environmental Protection Agency approves the standard. The pollution study will have a separate comment period.
The standard will apply to the stretch of the Mississippi River running from its confluence with the Minnesota River at Fort Snelling to upper Lake Pepin at Red Wing. The proposed standard addresses water clarity and the growth of rooted vegetation needed for a healthy ecosystem.
The south metro Mississippi has benefited from improved wastewater treatment and the separation of stormwater from sanitary sewer lines during the past two decades, resulting in a significant improvement in several indicators of river health, such as higher dissolved oxygen, lower ammonia toxicity and greater fish abundance.
However, the Mississippi remains severely impaired by suspended solids that prevent the growth of healthy rooted vegetation in shallower areas of the river, especially between the St. Paul barge terminal and Hastings. Total suspended solids (TSS) are tiny particles of soil and other matter that remain dispersed - or suspended - in water, making the water turbid or cloudy. This cloudiness prevents sunlight from penetrating the water and growing rooted aquatic vegetation, thereby reducing fish and wildlife habitat. The particles also carry nutrients that cause algal blooms.
The proposed Mississippi River standard for summer months includes the following components:
-- 32 parts per million of total suspended solids at Lock and Dam No. 2 and No. 3, a decrease from the current seasonal average of 47 ppm. After extensive research, the MPCA believes this standard will allow enough light penetration to grow more submerged aquatic vegetation.
-- 21 percent or greater frequency of occurrence of submerged aquatic vegetation - roughly double the frequency with which this vegetation is currently found in main channel border areas suitable for its growth. For example, if a researcher took 100 river samples, at least 21 of them would need to include the desired vegetation species to meet this part of the standard. Considerably higher frequencies would be expected for backwaters.
The MPCA believes this site-specific standard will lead to an improvement in the aquatic ecosystem of the south metro Mississippi River, with benefits to fish, waterfowl and mussels, along with improved aesthetics and recreation.
The deadline for comments, which must be in writing, is 4:30 p.m. on March 26. Submit comments to Norman Senjem, MPCA, 18 Wood Lake Drive SE, Rochester, MN 55904, by fax at 507-280-5513, or by e-mail at norman.senjem@state.mn.us. Senjem can be reached by phone at 507-206-2655 or toll-free at 1-800-657-3864.
Additional details about the proposed standard can be found on the MPCA Web site at www.pca.state.mn.
