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Wetland complex is a backcountry escape in the heart of farm country

  • 8/14/2018 12:50:00 PM
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Fonda, Iowa – The Sunken Grove and Leo Shimon Marsh Wetland Complex becomes Grand Central Station twice a year for migrating ducks, geese, pelicans and shorebirds that stop to rest and refuel before resuming their journey. The nearly 1,300 acres of wetlands, marshes, prairies and timber is surrounded by some of the most productive farmland in the world in southwest Pocahontas County.

“Having a spot like this in this part of the state makes a lot of the locals pretty happy it’s here,” said Clint Maddix, wildlife management biologist for the Iowa Department of Natural Resources.

“This area is one of my favorites. If you want outdoor recreation, you don’t have to go any further than this spot. There’s nothing you can’t do here: paddle, bird watch, hunt, take pictures.

“Look at it from the inside. Drive back there, it feels like it’s a different part of the state; a different part of the world, multiple ecosystems in a small package.”

The complex developed out of a mix of public land acquired by different county, state and federal agencies for public use.

Sunken Grove covers nearly 800 acres with a 240-acre marsh that has been attracting more interest from paddlers, birders and has hosted hunters from Minnesota and Wisconsin.

Leo Shimon Marsh covers 480 acres with an 80-acre marsh spread between two lobes. Pulling in to the parking lot and the new gravel boat ramp on the south end of the area a family of eight mallards decided it was time to go.  

Maddix is preparing the marsh to be at crest when duck season opens. It has a nice crop of arrowhead on the southern lobe and bulrush at the outlet.

The area is in the heart of the prairie pothole region where resident ducks and geese produce and raise their young. He has a vision for the area that includes adding wetlands basins, getting water back to a drained oxbow and increasing the plant diversity on the prairie.


Battling unwanted invaders

It’s a constant battle to keep carp out of the marsh, honeysuckle from the timber and cottonwoods out of the prairie and visitors can see the fight up close near the main boat ramp at Sunken Grove Lake.

Maddix said they used aerial spraying to kill honeysuckle late last fall after native species had gone dormant and then followed that up by grinding the dead honeysuckle this summer. This allows sunlight to hit the forest floor which is necessary for oak regeneration. Unfortunately, another invader has its eye on the newly opened real estate – buckthorn.

A different kind of battle is going on in the prairie and marsh.

If left unmanaged, trees will encroach on the prairie and at Leo Shimon Marsh Wetland Complex that will likely be willows or cottonwoods. Fire is used to keep trees at bay and reset the prairie allowing different plants to shine. This year happens to be a banner year for rattlesnake master.

A combination of fish barriers and water control structures are used to prevent carp and bullheads from entering the marsh and allow Maddix the ability to dewater it if any got in.



A tornado came through about seven years ago and blew down a cottonwood tree where eagles were nesting, killing one of the eagles. The surviving eagle found a new mate and built a new nest near the old one. It has been active ever since.

The area is home to a large population of great blue herons and an active heron rookery. Shorebirds, pelicans, snow geese, bitterns migrate through. Waterfowl use peaks in October. The marsh is a popular spot with birders and a big time migration stopover after spring ice out.

Sunken Grove Lake has an area kept open near an overlook platform with picnic tables, a park grill and trash can. There is no bathroom, water or electricity available.

Pheasants and waterfowl are the top game species; deer and turkey are overlooked. It’s popular with shed antler hunters, mushroom hunters

Hunters are required to use steel shot only for all hunting except for deer and turkey. No motorized boats are allowed on Leo Shimon Marsh. Boats with motors are allowed on Sunken Grove.