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DNR announces a series of water-level drawdowns

By MWA, 09/27/17, 10:45PM CDT

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The Minnesota DNR earlier this week announced it would be conducting drawdowns on two wildlife management lakes, and maintaining low water levels on a third – all part of an effort to control rough fish numbers and improve the quality of the basins for waterfowl and other migratory birds.

Active water-level management has become an increasingly important method for maintaining the quality of the state’s wildlife lakes. Lowering water levels helps to induce winterkill of undesirable fish and also exposes bottom sediments and allows vegetation to flourish. Water-level drawdowns simulate the drought conditions that naturally would recharge shallow lakes and wetlands.

Following are DNR news releases on three of the drawdowns and water-level reductions planned for this fall:

Drawdown on Waseca County’s Goose Lake

A continued decline in wildlife use and water quality on Goose Lake in Waseca County has prompted managers with the Minnesota Department of Natural Resources to begin lowering water levels. 

Water levels will be lowered as far as possible prior to freeze up, and those levels will be maintained through ice-out in an effort to control rough fish. Water levels will continue to be maintained as low as possible throughout the summer of 2018 to expose bottom sediments, which will allow aquatic vegetation to germinate and become re-established in areas where it has declined. Area wildlife staff first observed large numbers of common carp in Goose Lake in 2016, when record rainfalls and flooding allowed carp and other rough fish to enter the lake.

A drawdown was attempted in the winter of 2016, but due to mild winter conditions, the goal to reduce rough fish was not met. Emergent aquatic vegetation has also declined on the lake in recent years, primarily due to natural processes such as grazing by muskrats. Continuing the drawdown through the summer of 2018 will expose bottom sediments and allow new emergent vegetation to become established.

Following a successful drawdown, in fall of 2018 some stoplogs will be put back in the dam and water levels will be allowed to partially recover. The partial recovery will still have the lake runout level about 1 foot below normal runout elevations, which will allow newly established aquatic vegetation such as bulrushes, cattail, and arrowhead to become more well established and prevent uprooting. Stoplogs will remain set approximately 1 foot below normal runout elevations through fall of 2019, when the full complement of stoplogs will be replaced. The basin will naturally refill as weather conditions allow.

Access to the lake during the drawdown is expected to become more difficult by late fall because of muddy conditions left behind the receding waters. However, one benefit to the drawdown is improved birdwatching.
 
Drawdowns simulate drought conditions, which are the natural “reset” mechanism for shallow lakes and wetlands. Lowering water levels during the winter should help to greatly reduce the number of common carp and other rough fish in the lake that are destructive to beneficial aquatic plants and invertebrates, and will allow for the regeneration of emergent aquatic plants that are important to wildlife. 

Goose Lake is a 434-acre shallow lake located in Waseca County that was designated as a wildlife management lake in 1978. It is one of only 56 such lakes in the state.  This designation allows DNR managers to take steps such as temporary drawdowns to help mitigate for factors that affect water and habitat quality and quantity. 

The project’s funding is provided by the DNR Game and Fish Fund along with proceeds from the Minnesota waterfowl habitat stamp. Revenue from stamp sales is dedicated to waterfowl management and habitat work. Stamp sales generate about $700,000 per year for waterfowl habitat enhancement projects on state wildlife management areas and shallow lakes.

Drawdown on Rice Lake in Steele and Dodge counties

A continued decline in wildlife use and habitat quality on Rice Lake in Steele and Dodge Counties has prompted managers with the Minnesota Department of Natural Resources to begin lowering water levels. 

Plans are to lower water levels as far as possible and maintain those levels through the winter to control rough fish and improve wildlife habitat. DNR wildlife staff found common carp in the lake In April of 2016, and subsequent surveys documented the decline in water clarity and losses of valuable wildlife food plants. Common carp destroy aquatic plants through their feeding actions; they also contribute to poor water quality in nutrient-rich lakes. A drawdown to reduce carp numbers was attempted over the winter of 2016, but mild winter conditions prevented rough fish reduction goals from being met.

Following a successful drawdown, the lake should begin to refill in the spring of 2018. After intentional drawdown efforts end, the stop logs will be returned to the dam and the basin will naturally refill as weather conditions allow.

Access to Rice Lake may become more difficult later in the fall for motorized boats. However, one benefit to the drawdown is improved birdwatching.
 
Drawdowns simulate drought conditions, which are the natural “reset” mechanism for shallow lakes and wetlands. Lowering water levels during the winter should help reduce the abundance of common carp and other rough fish in the lake that are destructive to beneficial aquatic plants and invertebrates. 

Rice Lake is a 715-acre shallow lake located in Steele and Dodge Counties. Rice Lake was designated as a wildlife management lake in 1985. It is one of only 56 such lakes in the state. This designation allows DNR managers to take steps such as temporary drawdowns to help mitigate for factors affecting water and habitat quality and quantity.

The project’s funding is provided by the DNR Game and Fish fund along with proceeds from the Minnesota waterfowl habitat stamp. Revenue from stamp sales is dedicated to waterfowl management and habitat work. Stamp sales generate about $700,000 per year for waterfowl habitat enhancement projects on state wildlife management areas and shallow lakes.

Low water levels on Willis Lake to be maintained

Low water levels will continue to be maintained through the winter of 2018 on Willis Lake in northwestern Waseca County, according to the Minnesota Department of Natural Resources. The lake drawdown began in 2016 after wildlife managers observed a substantial decline in wildlife use and habitat quality.

“The goal of this drawdown is to reduce rough fish,” said DNR area wildlife supervisor Jeanine Vorland. “Those fish such as common carp have a rooting behavior when they feed that prevent aquatic plants from getting established.”

The lake was drawn down over the summer of 2017 to allow new growth of aquatic vegetation to become established. 

“We’ve seen good response in both the quality and quantity of good food and cover plants for wildlife,” Vorland said. “Now it is important to reduce rough fish numbers to maintain good habitats.”

An attempt over the winter of 2017 was unsuccessful due to mild winter conditions and excessive runoff from last year’s floods. 

Plans are to keep water levels as low as possible through the winter of 2018 to reduce rough fish numbers and improve water quality and wildlife habitat. Following a successful winter drawdown, the lake should begin to refill slowly in the spring of 2018 from runoff, but water levels may continue to be lower than normal even after drawdown efforts end; it will take time for the basin to naturally refill from snow melt and rain. Access to the lake may be more difficult due to mud as the waters recede. An additional benefit to the drawdown is improved wildlife use and birdwatching.

Drawdowns simulate drought conditions, which are the natural “reset” mechanism for shallow lakes and wetlands. Lowering water levels during the growing season will stimulate regeneration of aquatic emergent plants, help stabilize fine bottom sediments, and improve water quality by reducing available plant nutrients that contribute to turbid water and summer-long green algae blooms.     

Willis Lake is a 116-acre shallow lake in Waseca County that was designated as a wildlife management lake in 2001. It is one of only 56 such lakes in the state. This designation allows DNR managers to take steps such as temporary drawdowns to help mitigate for factors affecting water and habitat quality and quantity.

The project’s funding is provided by the DNR Game and Fish Fund along with proceeds from the Minnesota waterfowl habitat stamp. Revenue from stamp sales is dedicated to waterfowl management and habitat work. Stamp sales generate about $700,000 per year for waterfowl habitat enhancement projects on state wildlife management areas and shallow lakes.