Dissolved oxygen is essential for a healthy fisheries habitat. Dissolved oxygen depletion is a problem in the study area in summer and in winter due to a variety of reasons. Conway Lake is relatively shallow with abundant aquatic vegetation. During the winter, excessive water enters Phillipi Lake through openings that are eroding, creating unsuitable habitat conditions for overwintering backwater fish. Shore Slough has less than optimal fish habitat conditions as a result of sedimentation and the high flows from Phillipi Lake.
The Conway Lake Habitat Rehabilitation and Enhancement Project is located in Pool 9 of the Upper Mississippi River, immediately upstream of Lansing, Iowa. The Conway Lake study area includes Conway Lake, Phillipi Lake, Shore Slough and Zoll Lake as well as the adjacent island and slough habitat. The entire study area is approximately 1,170 acres and completely within the Upper Mississippi River National Wildlife and Fish Refuge.
The project will enhance and create nearly 215 acres of floodplain forest and 93 acres of off-channel, backwater fisheries habitat. Nearly 200 acres of existing forest will be enhanced by planting seedlings in the forest understory, promoting forest diversity and providing resilience against invasive species. In addition, 15 acres of newly created forest will be constructed to support a diversity of desirable tree species, water velocities will be reduced in over 93 acres of the project area and dredging to depth of 6 feet or greater in 25 acres of the project area will improve overwintering fish habitat.
The U.S. Army Corps of Engineers completed the final feasibility study, which identified alternatives focused on maintaining and enhancing fish habitat and floodplain forest. Plans and specifications were completed in July 2017, and a construction contract for $5.2 million was awarded to Kaiyuh Services, LLC, in July 2018. Construction began in May 2020 and is expected to be complete by December 2021.
Congress originally authorized the Upper Mississippi River Restoration (UMRR) Program in Section 1103 of the 1986 Water Resources Development Act (WRDA) (Public Law 99‒662), codified at 33 U.S.C. § 652. Congress reauthorized the UMRR Program in WRDA 1999 (Public Law 106‒53).
The project is being planned and designed as part of a cooperative effort of the Corps, the U.S. Fish and Wildlife Service (USFWS), the Iowa and Wisconsin Departments of Natural Resources and local interests.
Project design and construction costs will be 100 percent federal because the project is located on lands managed as a national wildlife refuge. Operation and maintenance costs will be 100 percent federal, a responsibility of the USFWS.
Project Costs to Date $6,945,000
Estimated Total Project Cost $9,000,000