State explains upcoming work on Three Mile
Jun. 19—Preventing additional sediment from entering the water is the foundation for various improvements planned at Three Mile Lake.
During a meeting held Thursday at the the Three Mile Lake Lodge by representatives from the Iowa Department of Natural Resources and Union County Conservation, the lake has had work done since 2016 and has reached a point of more extensive improvements.
Other improvement work going back to 2016, valued at $1.9 million, was to improve fishing habitat, sediment and jetties, structures that benefit fish habitat and fishermen.
"We have more to do," said Andy Jansen from the Iowa DNR.
The discussion emphasized the plan to reduce the amount of silt from entering the entire lake. A silt dam, on the north end of the lake, takes in soil that flows with water entering the lake. The eroded soil within the water is left in layers on the north end and not enter the entire body of water. Research has shown the silt dam is nearing capacity and additional silt will eventually flow into the rest of the lake without changes.
In 2007, the lake itself was about 810 acres and had about 13,000 acre feet of water. An acre feet of water is the amount of water one foot in depth over one acre. When measured in 2019, it had reduced to 793 acres and closer to 12,000 acre feet of water because of the silt accumulation. The watershed for the lake is about 23,700 acres.
"We have real good water quality," said Union County Conservation Director Doug Jones about the lake's reputation. The lake is used for recreation and as a public water source.
The planned work, expected to begin in August, is to remodel the silt dam to increase its capacity for silt accumulation and prevent silt from depositing into the body of the lake. Dredging the lake, physically removing silt build up on the lake floor, was not financially feasible.
Other work includes strategic shoreline improvements and fish habitat. The entire project is estimated at $4.5 million which has been benefited by the state, many grants and a contribution from Union County. The lake is a tourist attraction for Union County bringing in people from across the state and others.
George Antoniou, from the DNR's lake restoration office, said the plan is for construction bids to be approved in July. In August, lake water level will start to be lowered to make construction more efficient. It's possible for the lake to be lowered up to 11 feet from capacity during construction. Antoniou said weather will play a factor considering extensive rain or snow during the winter and spring runoff. Refilling the lake will begin in February 2025.
Another factor is when Southern Iowa Rural Water Association's water treatment plant will be operational. It is under construction east of Creston along U.S. Highway 34 and will acquire water from Three Mile. The plant is expected to begin use in early 2024. Officials from DNR and SIRWA are in ongoing discussions about the lake and work schedules.
"We are blessed," Jones said about the cooperation among all the entities. "Thank you for playing nice."
