Geneva Lake water control structure
Bringing new life back to shallow lakes, just in time for spring migration
MANKATO, Minn., April 17, 2008 – Actively managing fish and water levels can turn shallow lakes from a turbid to clear water state and improve habitat for wildlife. In partnership with the Minnesota Department of Natural Resources, Ducks Unlimited added water control structures and fish barriers to five southern Minnesota shallow lakes this past year, which will improve each lake’s ability this spring to produce the plants and invertebrates that attract ducks and other waterfowl.
“Improving one shallow lake is rewarding in itself, but completing five projects in one year is quite an accomplishment,” said Jon Schneider, manager of Minnesota conservation programs for DU. “Shallow lakes are so important for humans, waterfowl other wetland wildlife, yet they are an enigma to improve and manage due to their large size and the complexity of threats impacting them. Shallow lake improvement projects often take years of work to fully engineer and resolve management issues.”
DU’s Living Lakes Initiative aims to improve 400 shallow lakes in Minnesota and Iowa. This cooperative work between DU and DNR will help fulfill the shallow lake goals of both DNR’s Duck Recovery Plan and DU’s Living Lakes. This work also addresses the habitat objectives of the North American Waterfowl Management Plan.
Shallow lakes are large wetlands greater than 50 acres in size but less than 15 feet deep. These lakes contain abundant aquatic plants and invertebrates sought by ducks (and duck hunters) when managed for clear water. Unfortunately, many shallow lakes in southern Minnesota and Iowa can no longer support these plants and invertebrates. They have been reduced to a turbid-water state brought on by invasive fish such as carp, excessive nutrients and increased drainage from the degraded landscapes that surround them.
Three of the lakes on which DU completed projects this past year are legally designated by DNR for wildlife management purposes. This designation allows DNR to manipulate water levels. In Blue Earth County, south of Mankato, DU designed and implemented an innovative water control structure and fish barrier on the outlet of 508-acre Rice Lake, featuring a long concrete trough carp can’t navigate up to get into the wetland.
On 1,875-acre Geneva Lake near Albert Lea, DU put in place a new variable crest water control structure with a horizontal steel bar fish barrier on the downstream end to replace an old, fixed crest dam, in partnership with Freeborn County and DNR. The structure is being used to conduct a temporary draw-down of water levels in the lake, and DNR treated the lake with the fish toxicant “rotenone” this winter. Management plans call for DNR to stock the lake with predator fish like northern pike to further minimize carp and other problematic fishes.
In Waseca County, DU placed a vertical steel bar fish barrier on the outlet of 370-acre Goose Lake to keep carp out, and DNR will manage the lake to allow for frequent natural fish winterkill.
DU also implemented a project on private land downstream of 115-acre Mott Lake on the Mueller Wildlife Management Area in Waseca County that features a DU-engineered velocity tube fish barrier. Fish in Mott Lake frequently winterkill. The velocity tube will prevent carp from again infesting the lake.
In southwest Minnesota, DU also designed and completed a new variable crest water control structure with vertical steel bar fish barrier on the outlet of 70-acre Hjermstad Lake within the Hjermstad WMA in Murray County. DNR will use the structure to temporarily draw-down the lake and may stock the lake with beneficial predator fish.
These and other shallow lake projects were cooperatively funded by the DNR, the Minnesota Environment & Natural Resources Trust Fund through grants recommended by the Legislative-Citizen Commission on Minnesota Resources for Minnesota’s Habitat Conservation Partnership, the North American Wetlands Conservation Act, a major gift from the Voss Estate and gifts from local chapters of the Izaak Walton League of America and Pheasants Forever.
“DU is very grateful for our strong public and private partnerships that help keep our Living Lakes Initiative so effective,” stated Ryan Heiniger, DU’s director of conservation programs for Minnesota and Iowa. “Without strong support from all partners, DU would not be able to deliver this challenging and effective conservation program.”
Other DU cooperative shallow lake improvement projects in southern Minnesota, pending for future implementation, include Bear Lake in Freeborn County; Eagle, Perch, Hobza, and Cottonwood Lakes in Blue Earth County; Rice Lake in Faribault County, Buffalo Lake in Waseca County; Augusta and Hurricane Lakes in Cottonwood County; Dovray Marsh in Murray County; Gislason Lake in Lincoln County; South Twin Lake and Cupp’s Slough in Lyon County; and Curtis Lake in Yellow Medicine County.
With more than a million supporters, Ducks Unlimited is the world’s largest and most effective wetland and waterfowl conservation organization with almost 12 million acres conserved. The United States alone has lost more than half of its original wetlands - nature’s most productive ecosystem - and continues to lose more than 80,000 wetland acres each year.
For more information on DU’s programs in Minnesota, www.ducks.org/livinglakes.
Conservation contact: Jon Schneider, 320-762-9916 email@example.com
Media contact: Becky Jones Mahlum, 701-355-3507 firstname.lastname@example.org