Just an update to this sorry affair. I had a 5th contractor out to give me a quote. This one I provided with the Storm Water Plan in addition to the usual topo maps, etc. It took a while, but he came back with a quote of $69,800, double the first two quotes. He sited the SWPP and said he would likely need to rent some equipment for the job.

My vineyard friend has suggested we purchase a used excavator and a dozer and do it ourselves. Sounds like a good time, but I've never built a pond. So I may go back to one of the earlier ones and see if we can make it work with intensive oversight. At this price I should widen my search, despite the added travel and time expense. Any thoughts are welcome.