Ducks Unlimited (DU) has partnered with the Iowa Department of Natural Resources to rehabilitate West Swan Lake
, a 1,000-acre shallow lake in northwest Iowa. Work on three new water control structures began in mid-November. The $700,000 project is set to finish in March of 2023, after which, site managers will be able to better control water levels and return West Swan to its natural state while keeping invasive species, like common carp and bullhead, out of the lake.
“It’s open for recreation, but right now there is little public use of West Swan Lake because of the state it’s in,” said DU Regional Biologist Mike Shannon. “West Swan should be a multiple use lake. When the work is done, it will be used for duck hunting and fishing, plus other kinds of outdoor recreation. There will be great fishing opportunities but also a biological control on invasive species.”
The funding for West Swan’s new infrastructure was provided by a North American Wetlands Conservation Act (NAWCA) grant. DU and Iowa DNR have also injected money into the restoration project, which includes site planning and a fish stocking program once the water structures are in place. West Swan has little emergent vegetation and is overrun with carp, which have the same diet – invertebrates - as hen mallards. Due to the lack of habitat, waterfowl and native fish species such as yellow perch and northern pike sparsely use the shallow-water wetland. But once the enhancement is complete, managers can draw down the lake so that vegetation, like cattails, coontail, and sego pond weed, will grow.
“These shallow lakes need to be actively managed to promote aquatic vegetation and prevent carp and other rough fish from entering the system,” said Rob Patterson, wildlife biologist with the Iowa DNR. “We are very excited to get started with this project at West Swan. We believe the changes coming to the lake will be very beneficial to fish and wildlife species, as well as the public who use the lake.”
Drawdowns are critical to the overall health of West Swan Lake. Taking water off at key times during the year allows natural plants and grasses to grow. This helps filter the water, making it a cleaner environment for wildlife. Vegetation, such as cattails, provide nest cover and resting areas for waterfowl during the migration. And food sources keep ducks nourished and in good health. Fish also benefit from improved water quality.
“You can have a 12-inch yellow perch in three years when the water quality is this good,” Shannon said. “At some of our other projects, where we have made similar changes, the clarity Is tremendous. You can see seven feet down into the water.”
The two other structures will keep invasive carp and bullhead out of West Swan Lake. A fish barrier will be built near the outlet of Ingham Lake that will let water flow through but not invasive fish. A second structure will allow Iowa DNR to manipulate water levels in East Slough Marsh, between Ingham Lake and West Swan Lake, to improve habitat conditions and water quality flowing into West Swan. Once the health of the lake is in good order, Iowa DNR will initiate a yellow perch and pike stocking program. They may also add bluegill, which eat carp eggs, and largemouth bass, a natural predator of bullheads, to the watershed.
“West Swan Lake is going to be a great resource for hunters, to recreate, and for wildlife,” Shannon said. “It’s hardly being used by any of those three right now, but you’re going to see that change once the project is finished.”