Background/Discussion
Lake Manawa is a 785 acre natural oxbow lake that is owned, operated, and maintained by the Iowa DNR and located within Council Bluffs.
Iowa DNR is working to improve the water quality within Lake Manawa. Planned dredging creates additional depth and volume at Lake Manawa, both important to achieving long-term water quality goals. Historic lake dredging work deepened significant portions of the lake, and in 2016 an additional 500,000 cubic yards of material was removed. The resulting maximum lake depth is 22.5 feet; however large expanses of the lake still average between 6 to 7 feet of water.
The City of Council Bluffs owns or sponsors multiple levee segments, which encompass the City Federal Levee System, providing flood protection from the Missouri River, Mosquito Creek, and Indian Creek.
In order to meet the criteria for levee certification, seepage improvements are necessary for several reaches of levee. These projects require significant amounts of borrow material and finding suitable material at a reasonable price has been a challenge for the program.
The DNR’s and City’s purpose of entering into this Cooperative Agreement is to remove 500,000 cubic yards of material from Lake Manawa and temporarily stockpile on state property. The DNR’s other purpose for entering into this Cooperative Agreement is to have the City remove the material from state property and return the stockpile area to pre-dredge conditions. The City of Council Bluffs will use the stockpiled material for planned levee projects.
Annual CIP budgets include a programmed amount in Local Option Sales Tax funds for levee improvements. In addition to LOST funds, the City is able to capture a portion of the State sales tax revenues through the Iowa Flood Mitigation Program. Through this program, the City is eligible to receive $57M over a 20-year period. The accelerated schedule of the levee program requires a funding strategy that will allow large expenditures to occur in the next few years. The financing plan will likely include borrowing money for the short-term and then leveraging the IFMP reimbursements to pay back the loan over a longer period of time. The City’s consultant, PFM, is exploring multiple scenarios for borrowing the necessary funds. The City’s cost for the dredge material is a not to exceed amount of $1,500,000 and will be paid with funds from the levee program.