US Army Corps of Engineers
St. Paul District Website


Upper Mississippi River Restoration Program: Conway Lake

Published April 12, 2017
Updated: Sept. 20, 2019

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.


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 U.S. Army Corps of Engineers is considering introducing flow from a small creek to improve dissolved oxygen levels in Conway Lake. Flow restriction from Middle Slough would improve winter habitat conditions in Phillipi Lake, Shore Slough and Zoll Lake. The Corps will also pursue dredging in Shore Slough and Phillipi Lake.


The Corps completed the final feasibility study. Identified feasible alternatives focused on maintaining and enhancing fish habitat and floodplain forest. Plans and specifications were completed in July 2017, and contracted construction with Kaiyuh Services, LLC, for $5.2 million in July 2018. Construction is anticipated to begin in 2020 and be completed by 2022


The Conway Lake Habitat Rehabilitation and Enhancement Project is being planned under the authority of the Upper Mississippi River Restoration Program. This program was authorized by Section 1103 of the Water Resources Development Act of 1986 and reauthorized by the Water Resources Development Act of 1999.

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 and completely a responsibility of the USFWS.

Estimated total project cost                         $7,000,000
Funding allocated to date                             $7,000,000