OK, so you have something like this?...
Yep. Like to get rid of the bottom water, not the top.
I like your means of controlling water level. Have you considered annual flooding? Something like this.
After Fall turnover and O2 stable, reduce the water level exposing bank. Seed with rye and crimson clover(or other appropriate legume) and allow to grow over the winter. In the Spring, raise the water level and flood the newly grown vegetation.
This might be a good way to get winter grown primary production into your BOW on an annual basis. Crayfish and your newly introduced PK shrimp would use it for cover and feed. By summer it would be broken down and incorporated into forage.
Winter drawdown might also help your LMB growth through winter by concentrating BG.
