Although there are several accepted methods for determining the value of real property in condemnation cases, none of the methods seem to apply here. For example, you can't use "reproduction cost new, less depreciation" or "replacement cost" because you can't reproduce, replace, or depreciate a natural resourse. "Capitalization of income" also doesn't work for obvious reasons. And while "market value based upon comparative sales" might provide a some sort of a benchmark, how many arms length, bono fide sales of ponds are there where the surrounding real estate is not part of the transaction?
Personally, I would value the pond at cost, less 10% (because the ugly pink fence detracts from the value). "Fees" have nothing to do with the value of the property, so by law they can't be included within the condemnation value except to the extend specifically authorized by statute.
You would be a harsher judge than I would. :o) I'd cut the guy fees and a small profit and tell him to haul his ass outta my court. :o)