A complex of protection around a wildlife haven

Posted on July 27, 2016 in Blog


Duck season at Big Wall Lake; October 2015. 

Jim and Pat Dinsmore had been making a difference in the lives of students for years. Now they wanted to make a difference on the land, leaving a legacy of a healthier natural Iowa. 

Jim was an animal ecology professor at Iowa State University for almost three decades. He retired in 2002, having tutored and mentored many in the Iowa conservation community. The Dinsmores have also been giving scholarships to animal ecology students at ISU for 13 years. They recently starting searching for land in Iowa they could help protect and restore. 

“We wanted to do something that we could look at while we’re still alive and find an area that matches our interests. I’ve always been associated with wetlands and wetland birds,” Jim said.

That search led them to Iowa Natural Heritage Foundation, and, eventually, Big Wall Lake in Wright County. The Dinsmores pledged a gift to INHF in 2010 that enabled the purchase of a 130-acre addition to Big Wall Lake Wildlife Management Area last year. The James and Patricia Dinsmore Tract will eventually transfer to the Iowa Department of Natural Resources and become part of the growing complex of public land surrounding the 978-acre shallow water lake that is an important stopover on a major flyway for migrating waterfowl. 

“INHF is famous for giving people a way for their gift to make a difference,” Jim said. “Big Wall Lake is a beautiful natural marsh. To think there is potential to improve on that complex, that’s exciting. This could be the start of something that could be much larger.”

The changing lake landscape

Small hunting cabins dot the southeast shore of the lake, which has been the case for more than a century. A 1916 report by the Iowa State Highway Commission notes, “A small pleasure resort and several cottages are found in the grove south of the lake. ... Hunters from surrounding counties use the lake during open season. Considerable wild rice grows in its waters, which makes it a favorite feeding ground for ducks and geese.”

The report recommended against draining the lake, which had been requested by nearby landowners. The lake remained, but its water quality steadily declined over the years. According to Iowa DNR Wildlife Biologist TJ Herrick, it had become an open water system that suffered from static high water levels. By the beginning of this century, it was added to the state’s list of impaired waterways.

Big Wall underwent a major restoration starting in 2006. The removal of carp and other rough fish combined with increased outflow on the lake allowed aquatic plants to thrive. Herrick said the restoration was a success, returning the lake to more of a hemi-marsh — a mix of emergent vegetation and submersed plant life that is favored by water-dependent birds and amphibians. The lake was removed from the impaired list in 2012, allowing the Iowa DNR to focus on watershed management and protection on the land surrounding the lake. 


A pair of mallards perches on an icy shoreline, just beyond the grasses which contribute to excellent hemi-marsh habitat that attracts waterfowl.

Planning a prairie pothole system

In 2011, INHF purchased an adjacent 99-acre property (Phase I) on which the cropland was restored to wetland and grassland under the Wetland Reserve Program (WRP). That property has since transferred to the Iowa DNR and is the first piece of what will become a much larger complex on the west side of the lake. After restoration on the Dinsmore Tract (Phase II) is completed and transferred to the Iowa DNR, the next piece will be a 341-acre property (Phase III) on the northwest corner of the lake. The Dinsmores also made a contribution to that tract, and INHF is currently raising funds to make the transfer to the Iowa DNR possible. 

“This project is incredibly important,” said Herrick. “For years, until INHF purchased that first piece, there was zero upland habitat around the lake.”

Since the Iowa DNR began restoration on the first tract, Herrick said they’ve seen a lot of wildlife return to the area, including nesting wetland and upland birds. And, importantly, “The water quality is night and day different. It has really improved.”

The Iowa DNR plans to manage the complex as a prairie pothole system as “close to historic conditions as possible,” that will help to filter the water more before it reaches the lake. On the Dinsmore tract, there are plans to re-establish an oak savanna and remove a 1930s-era land berm that will help to grow the lake by 30-35 acres. They will also plug two existing agricultural drainage wells — an outdated drainage system that allows surface runoff and tile drainage from cropland to discharge directly into groundwater aquifers.

Herrick said this upland restoration could make Big Wall Lake a destination spot for pheasant hunters in addition to the duck-hunting haven it has always been. “It’s down there in an area that couldn’t be more intensively agriculture, but you have this pocket of wildlife habitat,” Herrick said. “Putting places like this on the landscape is so important. Not only for the habitat, but for the people. Kayakers, hunters, bird watchers — they’ll all benefit.

“The Dinsmore tract was dedicated at a ceremony in October 2015, which was attended by many of Jim’s former students, including INHF President Joe McGovern. “This tract would not have been possible without Jim and Pat,” McGovern said. “This is creating a buffer around Big Wall Lake, and it will have a tremendous impact on wildlife habitat and water quality.”