Lake drawdown launches major project for Diamond Lake in Kandiyohi County
ATWATER — Diamond Lake was host to the 2014 Minnesota State Archery Association Bowfishing Tournament, an event that saw the winners haul in five carp weighing over 158 pounds, one of them a 39-pound behemoth.
Those "glory" days are about to end.
With the turn of a valve July 20, a long anticipated project aimed at improving water quality in this popular Kandiyohi County recreational lake got underway.
Opening the valve started the drawdown of Schultz Lake. Its waters began flowing through a 1,700-foot pipeline buried 33 feet under a corn field.
"The Grand Canyon of Kandiyohi County,'' said Cory Netland, wildlife manager with the Minnesota Department of Natural Resources, in describing the trench required to bury the pipeline.
Netland joined Margaret Johnson, director of the Middle Fork of the Crow River Watershed, in outlining the progress on the Diamond Lake project to board members of the state Board of Water and Soil Resources and others on a tour Wednesday of conservation projects in the county.
The Diamond Lake project has been long in the making, and much work remains. Drawing down the waters of Schultz Lake will make it possible to add control structures between Schultz and Wheeler lakes and, eventually, the north and south bodies of Hubbard Lake.
The chain of lakes — Schultz, Wheeler and Hubbard — naturally flow into Diamond Lake.
The 460 acres of water represented by the shallow lakes represent 45 percent of the water flow into Diamond Lake, but deliver 74 percent of the phosphorus load that impairs it, according to Johnson.
Diamond Lake was listed as impaired starting in 2006 due to the excessive levels of phosphorus and chlorophyll-a, according to Johnson.
The water control devices are making it possible to temporarily reverse the flow of water from the lakes to bypass Diamond Lake. They flow directly into Kandiyohi County Ditch 28, which is the natural outlet for Diamond Lake.
The intent is to draw down the chain of small lakes and cause a winter kill of the carp and other rough fish that thrive in them. The drawdowns will also cause the heavy load of phosphorus suspended in their waters to settle and bind into the lake bottom sediment. These conditions will make it possible for native, submergent vegetation to re-establish itself in the lakes, according to Johnson and Netland.
Addressing the water impairments in the small chain of lakes should improve water quality in Diamond Lake to the point that it will no longer be considered impaired, according to Johnson. She noted that the small chain of lakes currently exceeds the water quality standards for shallow lakes by a factor of 10.
Diamond Lake is one of Kandiyohi County's most popular recreation lakes. It's known for its walleye, largemouth bass, northern pike and crappie fishing. Its 1,565 acres of water and 9.6 miles of shoreline are lined by cabins, a private resort and a busy county park.
As for the carp in Diamond Lake, the battle against them began earlier. In 2012, a fish barrier was installed on the waterway leading from the small chain of lakes into Diamond Lake. Four corrugated culverts run through a wall of piled rocks. The submerged culverts are capped at their ends but drilled with holes like perforated tile. Only the tiniest of fish can make it through the culverts; they effectively prevent adult carp from spilling out of the chain of lakes into Diamond Lake.
All the while, the Middle Fork of the Crow River Watershed District also continues to work with landowners in the basin to encourage best management practices to reduce the amount of nutrient-carrying sediment washed into the waterways, Johnson said.
Ducks Unlimited was able to access the Outdoor Heritage Fund to help make much of the work possible.
Phase one of the project, developing the structure for bypassing Diamond Lake and lowering Schultz Lake, cost just under $400,000, Johnson told the visitors Wednesday. Phase two, which involves adding the control structures to manage each of the lakes individually, will cost an estimated $350,000.
The watershed district has obtained $60,000 in easements for the project, and the DNR is providing staff resources.
The most important part of it all, said Johnson and Netland, has been the relationships with affected landowners. It is their cooperation that is making the project possible, they said.