Just thought I'd share a recent revision to my pond. Quick review, I have a 2.5 acre nearly 40 year old eutrophic pond in southeast Iowa. Newly built ave depth 13 ft, currently 8-9 ft.
After I had a shock survey done in September, one of the suggestions by the Fisheries Management staff was to consider raising my pond level. I had a local excavating company evaluate my dam and emergency overflow, and check via laser level how much I could raise my pond (maximum) before having water running out the emergency overflow. I had 4 feet of 'space' to work with. My plan is actually only to raise it 18 to 24 inches, and evaluate the effect on all the shoreline, plus any back flow into my silt ponds.
I chose to use a 'water inlet control structure' adapter, to modify my outflow pipe. It allows adding and removing 'slats' to control the water level. The existing outflow was an 18 inch corrugated steel pipe. See attached before/after photos.
Before:
After:
New outflow control structure schematic:
