I agree with the idea of an underflow wheel. To me, it's the most practical and our creek runs a pretty constant speed even when flooded. We even have a hole in front of the cabin which would be ideal for it. It's the issue of the requirements to permit it vs the return. The costs would just never balance out, even if I could afford that kind of money.
Dealing with the state would be the easier part of it all. It's our county which is the real deal killer.
It's humorus to watch adds for the county on TV where they talk about how much they support small farms after almost destroying the local farming industry. About 10 years ago, the county was requiring local farms to get clearing and grading permints to plow their fields or face stiff fines. To get the permit, they required the farmers to do environmental impact statements and put 2-5% of the applicable field(s) into protected habitat for before they would issue a permit for the remainder. This was required every time a farmer needed to plow a field. The farmers eliminated this requirement by getting an inititave on the ballot and getting it passed. The inititave simply stated that Normal Farming Operations were Exempt from the UBC (Unified Building Code).
Local News | Snohomish County farm initiative a hot button | Seattle Times Newspaper
"In addition, the current code says those exemptions don't apply on lands within environmentally critical areas,
which include wetlands, salmon habitat, aquifer-recharge areas and geologically unsafe lands. Grading permits, therefore, could theoretically be required for plowing in those cases."
Here in Western Washington, nearly all farmland (bottom land) qualifies as wetlands and that was the criteria that the county was using to require permits.