Have you had any sort of survey done to see where the waterline would be at different depths? It is pretty hard to estimate that sort of thing. How much water flows through the creek now and how much does it vary season to season? With flowing water you will have to have some sort of control structure that will handle the volume and also an emergency spillway to keep the dam from getting washed out in case of a deluge. I would think estimating that could get pretty complicated depending on the size of the watershed.
You should have some sort of agreement on sharing the maintenance and liability as well as usage or it could get ugly in the future.
It would be pretty cool to have a semi private bass lake! Go for it!
Jerry
