The Minnesota Pollution Control Agency (MPCA) has developed a new tool for tackling algae in the state’s water bodies: a proposed standard for rivers and streams. The idea is to prevent streams from becoming green and algae-covered. Though it will be one of many standards the agency uses to protect water quality, the proposed standard reflects both the latest science in the field and a sophisticated approach to managing water pollutants.
The proposed standard addresses river eutrophication — the process by which excess phosphorus causes too much algae to grow, creating a green, slimy condition in the water. Algae-covered rivers and streams are less attractive for boating, fishing, and swimming — highly valued pastimes in Minnesota. The new standard also serves the federal Clean Water Act, one goal of which is to protect water for recreation.
A sophisticated approach
Since 2008, Minnesota has had standards to protect lakes and reservoirs from excess phosphorus and algae growth, but the proposed standard for rivers and streams required additional study to formulate. Flowing rivers and streams react differently than lakes to pollutants such as phosphorus, and they react differently in different parts of the state.
“If you look at the numbers that we’re proposing to protect rivers, they’re different across the state because shallow waters, fast-flowing waters will have different rate of algae growth for the same amount of phosphorus,” says Katrina Kessler, manager of the MPCA’s Water Assessment and Environmental Information Section.
The proposed standard not only takes into account how much phosphorus has gotten into a river or stream, it also uses a measurement of how the river or stream responds to the phosphorus. “Just because phosphorus is there, doesn’t mean that algae is going to be there, too,” Kessler notes. So while a certain amount of phosphorus in a shallow, slow-moving stream with a straight waterway near Mankato may result in algae, the same amount of phosphorus in a deep, fast-flowing, curving stream outside of Fergus Falls may not cause algae to grow.
Even though this is a battle against the “green and slimy,” Kessler calls the standard “very sophisticated.” She notes that it requires more work to implement. “You can’t just go out and measure one thing. You have to measure two things, at a minimum, to understand whether or not the river or the lake is meeting the conditions you want it to meet. It’s so much easier to measure just phosphorus, and it’s certainly easier to implement permits that have phosphorus limits in them.”
But she says it’s “overly conservative and potentially a huge waste of economic resources to just put a phosphorus number together and put limits in permits or limits on land uses based on one number, if we’re not seeing environmental impacts.” So the proposed standard will be more complicated to administer, but will give the MPCA more flexibility in setting discharge limits and in writing permits for wastewater treatment plants, industrial facilities, and other regulated parties.
At the same time, the standard will help meet state and federal environmental goals. “The MPCA’s proposed standard for river and streams is an important new tool — one we haven’t had before — for making sure our rivers aren’t clogged with algae,” says Trevor Russell, water program director at the Friends of the Mississippi River, an organization devoted to protecting the Mississippi and its watershed. “The MPCA is to be commended for the work that’s gone into developing the standard.”
Concern for permit holders
The proposed standard is part of a larger set of emerging tools for protecting water quality, the development of which has been helped along by funds from the 2008 Clean Water Land and Legacy Amendment. While phosphorus contamination is the focus when dealing with algae, nitrogen pollution is also a concern in the state’s bodies of water, as a threat to aquatic life. The MPCA study “Nitrogen in Minnesota Surface Waters,” released in June 2013, lays the groundwork for reducing nitrates (a form of nitrogen) in lakes and streams and lessening the state’s contributions to water quality issues downstream. And the statewide Nutrient Reduction Strategy — which has been presented around the state recently — addresses both nitrogen and phosphorus. “All of the states that contribute to the Gulf of Mexico were asked by the EPA to put a Nutrient Reduction Strategy together,” Kessler says. “We’re one of the first to finish it.”
A concern for permit-holders and others affected by standards is part of all the agency activities related to protecting water in the state. Kessler notes that the MPCA is especially mindful of the need to make sure the requirements of the various standards line up — for instance, to implement phosphorus-standard numbers that will also cover what will later be required by the Nutrient Reduction Strategy. “Because we’ve heard loud and clear from regulated parties and the external stakeholders that are interested in this: ‘We don’t want a moving bar. We want you to tell us one number that we need to meet, overall,’” she says.
The proposed standard was developed by taking into account both the interests of a various stakeholders as well as the latest science, and it represents that balanced approach. The standard is open for public comment through Monday, January 13, 2014. To learn more about the standard and how to submit comments, visit the MPCA web page on new standards.
The MPCA will also hold a public hearing on the proposed standard on January 8, 2014, starting at 9 a.m., and again at 6 p.m. The hearing will be at the MPCA’s office in St. Paul. Live video conference links will be available at the MPCA offices in Duluth, Brainerd, Marshall, Rochester, and Detroit Lakes, for the convenience of the public. See the MPCA website for office locations.