Ameren Missouri operates Bagnell Dam under a federal license. Its dock requirements page tells owners to design for the lake they will actually get, not the lake on the Fourth of July.
The license, Ameren writes, allows the lake to fall to 650 feet under normal conditions and to 645 feet in an emergency. A dock designed for 650 will avoid most drawdown damage. A dock designed for 645 will have fewer problems if the emergency level shows up. Ameren says drops that large are not typical, and that the lake is usually lowest in winter and early spring. If you do not live here in February, someone still has to look at the dock.
Day to day, the level also moves because the Osage plant is used for power, downstream navigation, weather, upstream releases, and equipment. Ameren says forecasts beyond a short window are questionable. Do not build a schedule that depends on a predicted elevation three months out.
What moves when the water leaves
- A dock with tired flotation sits on its frame first. That is a refoam symptom, not a mystery.
- Cables and stiff arms sized only for a full pool go slack or bind. Mention drawdown damage in a repair request.
- Shallow cove ends get thin. Appendix B would rather see the dock relocated on your frontage, or a longer walkway, than a dredge project. Dredging under a dock is a last resort. There is a narrow dredge allowance down toward 650 feet immediately under an existing boat lift. That is not a general permission to deepen a cove.
- A FERC order from 2011 describes a normal pond near 660 feet Union Electric datum and a project boundary that generally follows about 662 feet. Those figures describe the full pool and the project line. The 650 and 645 figures are the operating drawdowns Ameren tells dock designers to use today. They answer different questions. Cite the dock requirements page for design, not a memory of “the lake is always 660.”
The public level line on Ameren’s page is 573-365-9205. Shoreline questions go to Ameren’s Shoreline Management office. Appendix B lists that office at 3 Willmore Lane in Lake Ozark. That is Ameren’s address. It is not an office of this website, and this website has no walk-in counter.
If you are designing a new dock or a roof, say on the form that you care about low water. The builder should be thinking about 650 whether you say it or not. Saying it keeps the conversation honest.