'A resource worth saving'
MANHATTAN BEACH—With a cold-water fishery and natural sand beaches, Big Trout Lake supports Crow Wing County's only population of stocked lake trout and its second-highest taxable land values.
It's among the farthest southwestern Minnesota lakes supporting the species more commonly associated with the Boundary Waters Canoe Area Wilderness. Here, shoreline property sells for about $4,200 per foot.
"That's an important resource, and it's a resource worth saving," said Jeff Laurel of the Whitefish Area Property Owners Association.
This spring, the Crow Wing Soil & Water Conservation District finished a $400,000 stormwater treatment project designed to protect Big Trout Lake's water quality.
The Minnesota Board of Water and Soil Resources ranked the project No. 1 among its Clean Water Fund grant priorities for 2016. The $310,000 BWSR award helped pay for pipes and three underground sediment-collectors off Crow Wing County Highway 66.
Previously, untreated runoff from 121 acres carried algae-feeding phosphorus and other pollutants into the lake through a series of ditches, gutters and a culvert. The project on the edge of Manhattan Beach will keep an estimated 40 tons of sediment—about three dump truck loads—and 40 pounds of phosphorus out of the lake annually.
"I remember a time when that bottom was all sand. No weeds at all," Laurel said. A retired Twin Cities software and systems company owner, Laurel grew up spending summers on Big Trout Lake. He moved here full-time in 2012, and serves on the WAPOA board. "Since the early '90s we've noticed that there's been more weed growth in the lake, and more algae in the lake as you get later into the summer."
Water clarity has decreased by about 10 feet since 1992.
Nutrient-loading threatens species such as lake trout, lake whitefish and cisco—also known as tullibee. All three are present in Big Trout Lake. All three need cold water plus sufficient oxygen levels, but lake trout are the least tolerant.
Decomposing algae on the lake bottom depletes the cold-water oxygen supply.
"We're often on the edge," said Owen Baird, a Brainerd-based Minnesota Department of Natural Resources fisheries specialist. "The cold water's there, but the oxygen's kind of on the low side."
Lake trout require oxygen levels of about 5 parts per million.
"If it gets under 3 ppm, the water's cold enough but they can't breathe. They could go higher up in the water column, but then it's 60-degree water and they're kind of hot and unhappy," Baird said.
Reducing phosphorus in particular will improve oxygen levels.
"Eventually, we're going to see a resulting decrease in the weed growth and in the algae growth," Laurel said.
The WAPOA board set a precedent when it agreed to pay 75 percent of the estimated $1,500 annual maintenance cost to pump out the sediment collectors. (It's the first time the 1,100-member, 14-lake WAPOA spent money on a project tied to a road supported by tax dollars.) Manhattan Beach will pay the balance.
Manhattan Beach—a community of about 60—was reluctant to take on the entire 25-year maintenance commitment itself. So was the county. The county agreed to maintain the infrastructure.
"We got them to the point where they felt that it was worthwhile," Laurel said of Manhattan Beach officials. "Several groups recognized the importance of trying to reduce the nutrient load coming in through these storm drains."
Manhattan Beach was among them.
"We're happy from the standpoint that it got funded, correcting a potential problem that's there," said Manhattan Beach Mayor Paul Allen.
"Anything that we can do to help keep it clean I think is important. But a city our size to take on the undertaking of the perpetual care is the thing with the pumping of the diverters. That's where WAPOA and (the city) came into agreement," Allen said.
After the Crow Wing County water plan made Big Trout Lake a priority, the SWCD received a $10,000 Central Regional Sustainable Development Partnership grant to identify the source of runoff and propose a solution.
"It really identifies how difficult these projects are to do," Ron Meyer, CRSDP board member and Whitefish Lake resident, said of the five-year-long process. "This is one of the examples that we like to use where we get the seed money going, and we feel this is going to have an impact."
The ripple effect has reached well beyond Manhattan Beach.
Now, Crow Wing SWCD Manager Melissa Barrick said, Crosslake and county highway department officials are collaborating to identify where untreated stormwater is flowing into other lakes within the Whitefish Chain.
"It's just kind of exciting to see how this project spurred on these additional conversations," Barrick said.