Dustin,
I was looking at the topo map again and there is a 6 acre pond 3 miles SW of the property you are looking at. The watershed for that pond is around 400 acres and it looks like that pond is down a lot.
If that pond with a larger watershed can't stay full I don't know if you will be able to have a 10-15 acre lake.
Chris you can't really use that as a comparsion. Heck even the rivers dry up in west Texas. Dustin can relate to that sense he grew up on the Mathews ranch and the clear fork of the brazos river. There is not a lake or pond that stays full they all dry up in the summer time.
One thing to note is the slope of the watershed appears to be very steep a ravine if you will. I would guess that the net % of runoff is going to be fairly high in that area of the water shed.
