The Niangua Arm leaves the main lake mid-lake. A lot of owners who say “Camdenton” have their dock here or on a cove off it. Little Niangua is its own channel. Appendix B names both when it sets the main-channel length rule.
The length rule, applied here
On the channel, the dock, breakwaters, and a 100-foot buffer together stay within 25 percent of the opposite shore, and the dock including breakwaters stays within 350 feet. Narrower channel sections can use a reduced buffer if docks stay within 20 percent of the width. Inside a cove, switch to the cove rule: one-third of a cove that is 500 feet wide or less, or 25 feet off the center line, whichever limits you more, with a 100-foot maximum. Wider coves use 20 percent, up to 350 feet.
Bring a measurement, not a guess from a phone map, if you are close to the limit. Ameren can ask for a survey. The permitting page says Ameren reserves the right to require one to prove the facility is in the right place.
Lifts and new docks
A lift on the Niangua follows the same attachment rule as a lift at the dam: on a permitted dock, not on the lake bed, and inside the setbacks. If the lift is outside the dock and parallel to the shore, the setback grows with the lift’s length. The sizing guide has those multiples. A brand-new dock starts at new docks and the permit guide.
How to label the form
Town: Camdenton if that is the town you use, or whichever town is actually closer. Arm: Niangua. Cove: the name, or “main channel” if you are not in a cove. Mile marker if you know it. A request that says only “Niangua” is a long arm.