Comfort Lake – Forest Lake Watershed District rounds out multi-year project with fall alum treatment
In 1871, Elof and Eva Modig migrated to the United States from Sweden, purchased land near a small lake in southern Chisago County (at $1.25 an acre) and settled down to build a house and begin farming wheat. Over the next three decades, the couple had children and changed their last name from Modig to Peterson to Moody. By 1915, farming in the area was beginning to transition from wheat to dairy, and Charles Moody had taken over the family operation. He built a large blue round barn on the shore of the lake to use for milking cows and storing hay. At the time, round barns were popular across Minnesota; today, the Moody Lake “Big Blue Round Barn” is the only remaining round barn in Chisago County and one of only a dozen remaining in the state of Minnesota.
Since 2004, Chisago Lake Township has managed the Moody Round Barn and a portion of the old farmstead as a township park, offering opportunities for picnicking, shore fishing, and tours of the barn. Unfortunately, more than 100 years of farming in the nearby area have taken a toll on the lake. By 2010, Moody Lake was murky, full of rough fish, and prone to fluorescent green algae blooms.
Since then, the Comfort Lake – Forest Lake Watershed District has launched a multi-year effort to restore the lake and improve water quality through fish management, wetlands restoration, and projects with nearby farmers. These efforts have been wildly successful, cutting phosphorus flowing into the lake by 65% and creating better conditions for fish. This fall, the district capped off eight years of work with a whole-lake alum treatment that will put an end to Moody Lake algae, now and in the future.
The success of Moody Lake restoration efforts can be credited to years of careful research and planning by the Comfort Lake – Forest Lake Watershed District. Though the lake is only 45 acres in size, it is important within the larger watershed because it flows downstream to Bone Lake in Washington County, which is an active recreation lake with a public boat launch. The entire Comfort Lake – Forest Lake watershed drains to the Sunrise River and eventually the St. Croix. Through monitoring, the watershed district identified “hotspots” where large amounts of phosphorus were flowing into Moody Lake, causing excess algae growth and poor water quality. The district then prioritized the most cost-effective practices and best locations for projects to slow the flow of phosphorus.
Though phosphorus is often an ingredient in fertilizers, it is also a naturally occurring nutrient present in soil, feces, and decaying plant matter. In the case of Moody Lake, the watershed district determined that phosphorus flowing into the lake was mostly coming from wetlands north of the lake and a century’s worth of cow manure deposited in the surrounding landscape. With funding assistance from the Minnesota Clean Water Fund, the district excavated and removed nutrient-rich sediment from the wetlands, planted buffer strips to protect against future erosion and runoff pollution, and helped one nearby farmer to install fencing and implement rotational grazing to limit cattle access to wetlands on his property. All together, these projects have cut phosphorus-loading to Moody Lake by 480 pounds per year.
Once it had minimized the amount of phosphorus flowing into Moody Lake, the Comfort Lake – Forest Lake Watershed District turned its attention to built-up phosphorus already in the lake bottom sediment and water. Previously, in 2010 and 2012, the watershed district had harvested 3,600 small bullheads from Moody Lake and installed a low-velocity fish barrier to prevent rough fish from migrating into wetlands to breed. Managing the rough fish has helped to keep them from churning up the lake bottom where phosphorus-laden sediment eventually settles. A winter aeration system, installed in 2016, has also helped to prevent winter fish kills and keep the bullhead population in check. The alum treatment conducted this October pulled suspended phosphorus out of the water and will act as a seal on the bottom of the lake, trapping the phosphorus in the sediment. Without available phosphorus, algae will no longer be able to grow and reproduce at the rate it did before.
On October 3, HAB Aquatic Solutions, LLC applied 15,000 gallons of alum and 7,000 gallons of buffer over 17 acres in Moody Lake, as approved by the watershed district. Alum (aluminum sulfate) is a nontoxic liquid commonly used in water treatment plants to clarify drinking water. It binds with phosphorus to form an aluminum phosphate bond that is insoluble in water; it does not affect fish or plants. Photos taken one day before and one day after the Moody Lake alum treatment show a dramatic change from day-glow green to crystal clear as the algae almost immediately disappeared. Moving forward into 2019, the Comfort Lake – Forest Lake Watershed District plans to begin treating invasive curly-leaf pondweed on an annual basis to help keep the lake in good health.
Near a quiet corner in southern Chisago County, an immigrant-family and their descendants farmed and lived for more than 100 years. Today, the Moody Round Barn is listed on the National Register of Historic Places and offers a quiet roadside attraction for visitors to the area. Alongside that barn, Moody Lake has watched farmers come and go and neighborhoods spring up nearby. Thanks to the local watershed district, there’s a bright future ahead for Moody Lake, and nothing but clear water in sight.
To learn more about the Moody Lake alum treatment, go to: www.moodylakealum.com.
To learn more about alum treatments in general, go to: www.clflwd.org/documents/CLFLWD_AlumFactsheet_7-30-18.pdf.
East Metro Water 