Wapello, Iowa – The water at Lake Odessa will not be raised to normal levels for the 2019 Iowa waterfowl season to allow the area’s diverse forest resource to recover after prolonged major flooding by the Mississippi River.
Trees and wetlands shrubs at the Odessa Wildlife Management Area and the adjacent Port Louisa National Wildlife Refuge have been increasingly impacted by flooding from the Mississippi River with the most recent flood events beginning in late September 2018 when floodwaters overtopped the emergency spillway and exceeded Odessa’s normal fall water level by nearly 12 feet.
Floodwaters remained until the river dropped to normal in December, then returned again in mid-March, inundated the entire Odessa flood protection levee, and lasted for a significant majority of the growing season. The spring flooding was the fourth highest recorded on the Mississippi River at the New Boston gage, and was within 1/10 of one foot from being the third highest. As a result, Odessa reached levels almost 16 feet above normal in early June during this prolonged flood event.
Those back to back major floods are compounding the stress on the trees and shrubs near the wetlands, said Ben Vandermyde, forester with the U.S. Army Corps of Engineers Rock Island District.
“Tree roots need to dry out in order to rebuild and repair ahead of the next growing season,” Vandermyde said. For now, the trees are doing what they can to reduce the stress on their roots by casting off some of their foliage and while there will likely be some tree mortality; Vandermyde said the extent won’t be known until next year.
“If there ever was a time to give the trees and shrubs a break, it’s now,” said Andy Robbins, wildlife biologist with the Iowa Department of Natural Resources.
Water level management at Odessa is important because of the areas reputation as one of Iowa’s premier waterfowl hunting locations drawing hunters from all over eastern Iowa and western Illinois. It is also an extremely important stopover point for thousands upon thousands of migratory birds as they make their way through the Mississippi Flyway each spring and fall.
Robbins said that while many areas will still be accessible by boat this season, waterfowl hunters wanting to get back to their normal spots will need to make some adjustments in the way they hunt. “The area will still be huntable, but hunters will need to use small boats or mud motors to get around. The larger boats will have trouble,” Robbins said.
In addition to the damage cause to the trees and shrubs, the prolonged high water has prevented the establishment of wild millet, smartweed, sedges, and other waterfowl attracting moist-soil vegetation.
Buttonbush, known locally as buck brush, is a unique and important wetland shrub at Lake Odessa that provides cover and food for duck broods. It is also showing signs of stress. Keeping water off buttonbush is important for recovery because it’s pretty resilient, if given a chance, said Marcie Kapsch, refuge manager at Port Louisa National Wildlife Refuge with the U.S. Fish and Wildlife Service.
The Odessa complex is managed in partnership by the Iowa Department of Natural Resources, U.S. Fish and Wildlife Service, and the U.S. Army Corps of Engineers and all agree that the decision to not put additional water on the area this fall is in the best interest long term for habitat and wildlife that depends on it.
Meanwhile, the partnering agencies will shift their focus to repairing damaged portions of their respective flood protection levees, including a significant 1,200 foot levee break in the Port Louisa refuge caused by this spring’s flood. The DNR is currently planning to lend assistance to the U.S. Fish and Wildlife Service during the repair process.