The first order of business at the bimonthly meeting of the Poplar River Management Board on October 4, 2010 was acknowledgement of the $687,034 federal Great Lakes Restoration Initiative grant that was awarded in September. “This is a big deal,” said Lutsen Mountains co-owner Tom Rider. “A tremendous amount of work went into this. Only nine grants were awarded in the entire Great Lakes basin. We were the only one in Minnesota. It’s a significant accomplishment. Thank you, everybody. Very well done.”
The grant will be used for several projects aimed at keeping sediment out of the Poplar River and is expected to help move the river toward de-listing as an impaired waterway.
The most expensive and complicated grant-funded project will mitigate runoff in a large gully on Ullr Mountain. Placement of maintenance buildings, the presence of county roads, and natural topography have contributed to sediment deposits from this gully since the 1940s or 50s, Rider said.
A high-density polyethylene pipe called a tightline will carry water down the slope where it will be funneled into a concrete vault that will filter the water and dissipate its energy before it empties into the river. The structure will be designed to handle a 100-year flood event. “Construction is going to be a challenge,” Rider said, “because this is steep.” He thought they might need help from people who have installed such systems in the mountains out West.
The Ullr Tightline project will begin next summer. It is expected to reduce sediment load into the river by 90 tons per year.
The next project is the Caribou Highlands flow path corridor. It will utilize things such as rock-lined ditches to correct erosion problems caused by the town home development and a ski run. It is expected to reduce sediment load into the river by 80 tons per year.
The last two projects are improvements that would reduce sediment from the lower Eagle Mountain Road and realignment and armoring of the lower Mystery Mountain flow path. They are expected to decrease the Poplar River’s sediment load by 105 tons per year.
In combination with the already completed stabilization of the Megaslump, the projects funded by this grant will result in alleviating 70% of the sediment load in the lower Poplar River, which is the section that has been identified as most problematic.
A kickoff event, required under the terms of the grant, will be held in Lutsen later this fall. The Poplar River Management Board hopes to get as many community members and elected officials—at both local and state levels— to this event as possible.
Setting the standard of
acceptability
While the PRMB works on reducing sediment from the Poplar River, the Minnesota Pollution Control Agency is still determining what the standards for healthy rivers should be and how they will be measured. Karen Evens of the MPCA reported that the new standards it is developing regarding Total Maximum Daily Load (TMDL)—the amount of pollutants a water body can receive and still meet water quality standards—may be ready for federal Environmental Protection Agency (EPA) review by June 2012.
The Poplar River was listed as impaired based on its turbidity, or lack of clarity. Evens believes the new standard might be the amount of suspended solids instead—a slightly different way to evaluate the health of the river. Turbidity is an old standard from the 1970s, Evens said, and not many states still use it. Factors other than sediment, such as algae in the water, can add to turbidity.
Evens was not sure if a suspended solids measurement would include all solids, both organic and inorganic, or just sediment, which is inorganic. PRMB engineer Curtis Sparks pointed out that eggs and larvae could add to the measure of suspended solids if it included organic matter.
Thepart of the river that will be sampled will be the central portion about 2/3 down where the water moves most quickly.
Standards will be set by eco-regions throughout the state, with more specific standards for some sites such as the Red River Valley and the Mississippi River. This eco-region will be roughly what is already known as the Arrowhead region, Evens said.
A river without development along it but similar in topography has been sought as a comparison to the Poplar River. ThePigeon River was a contender at first, but now the Beaver River is being considered.
Lutsen Mountains co-owner Charles Skinner asked Evens if the standard would be low enough to account for natural turbidity in the water, which is prevalent in many rivers along the North Shore after heavy rains. Evens was not able to give an answer on behalf of the MPCA. She said the agency might allow 10% “exceedance” from multiple samples taken during a range of weather conditions and averaged over the course of a spring-to-fall season.
Rider speculated that even 300 years ago, the Poplar River would have exceeded the current standard after a big rain. Evens did not think specific standards would be made for individual rivers along the North Shore because coming up with those standards would be time-consuming and use more resources than the MPCA has. County Commissioner Bruce Martinson said the MPCA would look bad if a natural river without development along it didn’t meet the standard.
“You do have some watersheds that are consistently meeting the standards along the North Shore,” Evens said. Two of those are the Baptism and the Brule rivers.
Evens estimated the Poplar River would need to meet standards—whatever they may be—for at least three years before a proposal to de-list it would be allowed. The MPCA would need to submit a proposal to the EPA before any body of water could be de-listed.
Whatever improvements are made to keep sediment out of the river will need to be maintained, community member Bruce Zimpel pointed out. An avid fisherman, he was one of the first people to raise the alarm about sediment in the Poplar River many years ago.
Other projects
Engineer Sparks said he might pursue grant funding for a couple of other projects along the Poplar River. One would be a walking trail leading upriver from Caribou Highlands and another would be refurbishment of trails that already exist but need erosion and safety improvements. He added that some of the nearby landowners would support better access to the river.
Sparks said one unique aspect of the Poplar River projects is that they were initiated by landowners adjacent to the river rather than by governmental entities mandating remediation.
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