Pelican Lake Enhancement
$2,000,000 in the first year is to the commissioner of natural resources for an agreement with Ducks Unlimited to construct a gravity outlet, water control structure, and pump station lift to enhance aquatic habitat in Pelican Lake in Wright County. A list of proposed land restoration and enhancements must be included as part of the required accomplishment plan.
A network of natural land and riparian habitats will connect corridors for wildlife and species in greatest conservation need.Core areas protected with highly biologically diverse wetlands and plant communities, including native prairie, Big Woods, and oak savanna.Improved aquatic habitat indicators.
Construction of a gravity outlet, water control structure, and pump lift station, allowing for drawdown of Pelican Lake, the next phase in the process of restoring what was once one of the region's premier waterfowl and wetland wildlife habitats.
Pelican Lake, located in eastern Wright County within ½ hour of the Twin Cities metro area is a shallow lake known statewide for its waterfowl production, migration, habitat, and hunting opportunities. Pelican Lake is one of 47 state-designated wildlife lakes in Minnesota. This shallow lake basin has no natural watercourse inlets or outlets. Since the late 1950s and particularly, since the late 1970s, Pelican Lake has experienced a decline in water quality and a loss of the extent and quality of aquatic plant communities that once supported wetland wildlife habitat. This decline in water quality and loss of plant communities is associated with high lake levels and watershed land uses that increase water runoff. Agricultural land uses such as tiling and ditching within the Pelican Lake watershed have altered the natural hydrology and contributed to the decline in water quality. High water levels in Pelican Lake have contributed to persistent and increased rough and game fish populations, as well as a shift from rooted aquatic plants (macrophytes) to algae-dominated (plankton) communities. Increased turbidity due to re-suspension of bottom sediments and algae has resulted in the absence of rooted macrophytes from large areas of the lake. These macrophytes, when present, moderate wave action, stabilize bottom sediments, uptake nutrients, and provide habitat for invertebrates. These factors have resulted in Pelican Lake changing over time from a “clear water state” to a “turbid state”. These changes have resulted in negative effects on lake productivity for waterfowl and shorebirds that historically used Pelican Lake as a migration stopover destination. The loss of important food sources associated with diverse macrophyte and invertebrate communities is the primary factor associated with declining use of the lake by waterfowl and shorebirds.
The work needed to restore Pelican Lake to former condition will be extensive and will rely on strong partnerships to implement the planned multiple phases. The total scope of the project includes reducing high water levels, constructing an outlet weir, constructing new segments of stream channel, restoring a 180-acre wetland, stabilizing the lower reaches of Regal Creek, and constructing a velocity-tube fish barrier. The components of the work to restore Pelican Lake will be completed in phases as funding is secured, to meet timeline requirements (i.e. Item A has to be done before Item B is installed), and to complete the work as efficiently as possible.
For this specific funding request, the Minnesota Department of Natural Resources (MDNR), in cooperation with Ducks Unlimited, proposes to enhance Pelican Lake through managed drawdowns to lower the current historically high lake levels. The project focuses on the construction of a variable crest outlet weir and pump lift station which would allow for the gradual dewatering of the basin. The current lake elevation is just 3 feet below the breach runout elevation of Pelican Lake. The project proposes to include the installation of a lake outlet that will lower the lake by 1.8 feet, which would bring it close to the established ordinary high water (OHW) level. The addition of a pump lift station will provide an opportunity for temporary lake management drawdowns. A management drawdown of Pelican Lake will likely improve water quality by stimulating emergent and submerged vegetation, reducing/eliminating nuisance rough-fish populations, and binding and reconsolidating nutrient-rich lake sediments.
The Pelican Lake outlet will include construction of a stoplog weir structure. An intake pipe will placed within the bed of Pelican Lake. A pump station and force main will be installed to pump water from Pelican Lake to a point north of School Lake where Wright County Ditch No. 21 currently outlets from School Lake. Construction of the stoplog weir structure will be at the mouth of an existing private ditch that flows into Pelican Lake. The top of the weir is proposed to be approximately three feet wide. The stoplog weir will pass flows during normal operating periods and will be designed to manage Pelican Lake at an elevation of 952.2 feet (above mean sea level), the established ordinary high water level (OHW). A pump station will be constructed at the existing edge of the eastern-most bay of Pelican Lake. A 24-inch intake pipe will be installed from this point for 900 feet into the lake and be set at an invert elevation of 942.0 feet. The lift station intake pipe will involve placement of a structure within the lakebed to support the intake pipe at the proper invert elevation. A short, 24-inch forcemain will outlet into the new channel on the downstream side of the weir. A pump configuration will be installed to facilitate management drawdowns to a lower elevation than what would be possible with a weir structure alone.
The water level management described in this proposal is informed and supported by the Pelican Lake Management Plan (2012). The proposed project was also reviewed formally in a mandatory Environmental Assessment Worksheet (EAW) in 2009, which was put out for public comment. The Pelican Lake Outlet Feasibility Study completed in April 2005 discusses potentially viable alternatives for the project. The Pelican Lake Work Group reviewed options and organized and evaluated criteria from the study that formulated the basis of the proposed project.
In 2012, Ducks Unlimited completed bioengineering designs and preliminary construction plans for the Pelican Lake project. Ducks Unlimited will be identified as the construction deliverable partner at Pelican Lake, providing bioengineering expertise and construction supervision for each facet of this complex shallow lake enhancement project. Ducks Unlimited has made, and will continue to make, substantial in-kind contributions to this project.