Posted on April 1, 2026
MITCHELL — Lake Mitchell’s water retention capacity is not up to current standard, and officials are hopeful for a state waiver to be able to take on their dredging project.
Mitchell Mayor Jordan Hanson issued a statement on Monday that the Lake Mitchell earthen dam and spillway cannot safely pass a 50% Probably Maximum Flood (PMF), which is a requirement for reservoirs the size of Lake Mitchell.
The finding is the result of a recent study of Lake Mitchell’s earthen dam and spillway. The city is requesting a variance to stay at 23% PMF, which is what Mitchell’s earthen dam and spillway is graded at now, according to a study by Houston Engineering. The variance also requests, if granted, for the city to move forward with the lake dredge project.
South Dakota Department of Agriculture and Natural Resources (DANR) has reviewed the study and is “recommending approval of the variance request with qualifications.”
“The city is optimistic the project can get back on track after the DANR meetings conclude,” Hanson wrote.
Upgrading the spillway to meet requirements would not eliminate downstream risk, according to the study.
“This study and evaluation was to ensure the continued protection of downstream residents, property, and infrastructure,” Hanson wrote.
A detailed update is expected at the Mitchell City Council meeting on Monday, April 6, according to Hanson.
In October 2025, the Mitchell City Council hired Houston Engineering at a cost of $98,000 to conduct a breach dam analysis, a 50% PMF study and to update the city’s lake Emergency Preparedness Plan. One month earlier, Hanson said that DANR required these studies before reconstruction of the dam, which meant the Lake Mitchell drawdown couldn’t happen in 2025.
Mitchell Public Works Director Joe Schroeder told the Mitchell Republic on Monday afternoon there was no direct correlation between the Lake Mitchell dredging project and the state’s requirement to look at the earthen dam and spillway.
“It has everything to do with what’s holding back water,” Schroeder said.
According to City Planner Mark Jenniges, the state is looking at Lake Mitchell as a whole, separately from the lake project. According to Schroeder, the matter of the earthen dam and spillway is like bringing an older building up to current building code standards.
“Nothing to do with the structure itself. It’s basically looking at water coming at it and how that water is staged,” Schroeder said.
Schroeder noted if the variance was approved, the city still needs separate permits from the state to put a hole in the spillway, discharge water from the lake, and to put the spillway structure back together.
“All of those things still need to happen,” he said. “If this (variance) was approved, then we’re back to exactly where we were before.”
Houston’s breach dam analysis and the waterflow studies relied on computer modeling of the Lake Mitchell spillway, dam, and the effects of a breach downstream.
Previously, the drawdown bid for the lake was to be awarded in fall 2025 and then a dredge bid in spring 2026. Lake sediment is to be dumped at Firesteel Park near the lake.
In July 2025, the James River Water Development District board sent a letter to the Army Corps of Engineers and DANR about the Barr Engineering-led plan to lower Lake Mitchell by breaching the existing spillway dam and potential impacts on downstream water systems and communities. The letter suggested that a gated pipe or valve would allow for gradual drawdown, emergency shutoff during storm events, and improved protection of aquatic habitat and water quality.
The Lake Mitchell restoration project hopes to reduce phosphorus-rich sediment and algae in the lake, with sediment concentrated in the historic Firesteel Creek channel of the lakebed.
The state approved a $16.8 million Clean Water State Revolving Fund Program loan over 20-years at 3.5% interest in January 2025 for the lake project, and the city pledged sales tax revenue for the repayment of the loan. The loan application was a result of a ballot item in the 2024 city election, which passed by a margin of 30 votes. The project is estimated to cost $31.7 million, which includes $6.7 million in interest payments.
