I have a similar situation that occurs naturally, with the shallow end rising and falling. The sweet gums will eventually take over, or worse, chinese tallow trees will establish. Also willows. They are near impossible to get rid of if established. Just be ready to monitor it closely and do necessary harvesting. I would leave the water level to nature and let establish what will live in the environment. As the silt builds up in later years, much flora will develop.
On second thought, maybe to be able to hold in more water will help keep some species under control.
