Hidden in the southwest part of the Fredericktown Unit, in Iron County, is one of Mark Twain National Forest’s jewels, the 100-acre Crane Lake. Three years have passed since engineering inspections first revealed that Crane Lake’s dam does not meet federal dam safety regulations. Since then, the USDA Forest Service has been conducting engineering studies to identify options to address the deficiencies.
For readers who have not been following this issue, Crane Lake dam was built in 1959 and raised in height in 1972 before it was acquired by the Forest Service. The dam was never designed to pass 100 percent of a probable maximum flood event – a requirement for all federally-managed dams. Follow-up inspections showed the dam has structural, geotechnical, and hydraulic issues, and further, does not meet seismic design standards for potential earthquakes. Here are some updates on items of interest.
The partial drawdown will continue because the water control structure was damaged by large woody debris during the December 2015 flood. Lake levels continue to fluctuate after storms because debris floats in and clogs the structure. At most, water levels have dropped to eight feet below normal pool during dry periods.
A temporary boat ramp has been planned for construction so anglers and paddlers can access the lake when water levels are below normal pool. A contract to construct the temporary ramp is to be re-advertised shortly. The project was previously advertised in 2017, but bids came in too high and the job could not be awarded.
The Missouri Department of Conservation has plans to conduct a fish population survey in May, if the water level remains high enough to get the electrofishing boat launched.
The engineering studies have been completed. The hydraulic and hydrologic analyses determined how much of a probable maximum flood could be passed by the current dam, and then, what options could be employed to bring the dam into compliance with federal dam safety regulations. For example, options include modifications to the dam, such as raising the earthen embankment, widening the spillways, and/or lowering the spillway walls.
Structural deficiencies with the concrete in the spillway chutes and walls must be designed with earthquakes in mind, which is of importance because of Crane Lake’s proximity to the New Madrid fault. No matter what modifications and repairs are planned, they must be designed for the maximum credible earthquake. For Crane Lake, the engineering firm calculated that is a 5,000-year return period earthquake.
Forest Supervisor Sherri Schwenke will make the decision on what repairs will be made to Crane Lake, but to do that, she first wants information from people who enjoy and appreciate Crane Lake and its surrounding national forest lands. She heard participants at the 2017 listening post and reviewed comments from the 2015-2016 open houses hosted by Mark Twain National Forest, but she wants to solidify her understanding about what you have enjoyed about Crane Lake in the past, what activities have been most enjoyable to you, and what you want Crane Lake to be like in the future.
To gather this information for Supervisor Schwenke, three local-area residents have volunteered to help me reach out to recreation and outdoor user groups, tourism organizations, Crane Lake neighbors, and elected officials over the next two months. These three dynamic individuals are: DeNae Gitonga, the community development specialist with University of Missouri Extension; Bill Bennett, a former educator and current director of the River Valley Region Association; and Don Firebaugh, an avid angler and outdoorsman and Madison County Clerk.
After visiting with people in these focused groups, we will then invite everyone interested in Crane Lake to an evening Community Forum on July 12, 2018, at Arcadia Academy. We will summarize what was heard at the focused meetings and we will validate this information with the Community Forum participants. Everyone at the Forum will work together to explore some of the findings in even more detail. We will also talk about the Forest Service’s environmental planning process that is now underway and how it will inform Supervisor Schwenke’s decision.
I will share more information about the Crane Lake Community Forum as the date approaches. If you have any questions before then, you can send me an email at firstname.lastname@example.org or give us a call at the Potosi Ranger Station at 573-438-5427.
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