Let's say you don't want to mess with livestock - the agriculture angle may still be the easiest. I would see about leasing pasture to someone running cattle or sheep nearby (hopefully you're not too secluded to preclude that). Then I'd spend a couple thousand dollars to fence off some acreage for pasture below your intended dam site. Bring in the livestock, and hey, you need to put in a dam to water them! Your pasture payments should recover some or all of your fence costs, depending on how long you want the livestock on your property (I think a multi-year commitment will be required to interest a farmer and show sufficient agricultural usage).
Who knows, you may end up liking the smell of manure and get your own cattle (it only took me 15 years to get to like it).