A new standard for river pollution!

Tuesday, June 22nd, the Minnesota Pollution Control Agency (MPCA) Citizens Board voted to approve a new pollution standard for the Mississippi River in the metro area!

The proposed site-specific standard limits the amount of sediment pollution allowed in the Mississippi River between the confluence with the Minnesota River at Fort Snelling and Lake Pepin near Red Wing. This stretch, referred to as the South Metro Mississippi River, is clogged with sediment that harms aquatic life and recreation along the river. This sediment is also filling in Lake Pepin, the upper one third of which will be gone this century if no action is taken.

The approval of this new standard is a very important step toward creating a Mississippi River clean-up plan that will restore river health while doubling the expected lifespan of Lake Pepin.

Next steps

The MPCA approval isnt the last word on the standard. The regional office of the Environmental Protection Agency must also approve the new limits this summer.

Once approved by the EPA, the MPCA will finalize a clean-up plan for the river. This plan, called a Total Maximum Daily Load (TMDL) will be reviewed by a Stakeholder Advisory Committee (which includes FMR staff) before being opened up for public comment later this fall. The TMDL will then go back to the MPCA board for final approval — and work on Minnesotas biggest and best opportunity to clean up our Mississippi River will begin.

The clean-up plan

The TMDL clean-up plan will include pollution reduction goals specific to each of the major watersheds that drain to the Mississippi River. The Minnesota and Cannon River watersheds — largely agricultural basins that contribute high sediment loads — will be asked to reduce their pollution load by 50 percent. The Upper Mississippi River, St. Croix River, Vermillion River and other smaller watersheds will need to cut sediment runoff by 20 percent. Metro area cities will need to meet 25 percent reduction goals.

Getting technical

For those with a thirst for technical details — the original TSS or Total Suspended Sediment standard was 25 Nephelometric Turbidity Units — which corresponds to about 65 parts per million TSS. The new South Metro Mississippi River standard is 32 parts per million TSS summer average, measured at Lock and Dam 2 and Lock and Dam 3. Water quality must meet this criterion in at least half of the years over a 10-year period.

This standard sets a goal for future efforts to reduce sediment loads to the Mississippi River and, ultimately, Lake Pepin. If/when this new standard is achieved, aquatic vegetation in the river would roughly double, and the overall health and vitality of the rivers ecology would greatly improve. In addition, the expected lifespan of Lake Pepin would nearly double.

For more information:

• on the new South Metro Mississippi River standard, please visit the MPCAs project website,
• on the Clean Water Act and TMDLs, please visit our Impaired Waters 101 page,
• or contact FMR Watershed Program Director Trevor Russell.

— Trevor Russell, Watershed Program Director