I don't know what your topography is like in your area but if you have a stream water has to get to it. In our area most of our slopes are only 2-3 percent but enough so often there are natural small ravines caused by erosion that lead to these seasonal creeks. Ponds are often built with the dam paralell with the creek damming up one of these ravines. The ravine provides some of the pond depth without excavation and the additional excavation in the ravine provides soil/clay for the dam and additional depth. So they end up partially excavated and partially dammed.
Here is a pond I just built last summer that fits that description. In fact all three of my bigger ponds back up to a seasonal creek.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=459159NRCS agent can help determining the watershed for a proposed pond location very easily. They have software and topography maps that make it a snap. They also have area rainfall records and can recomend a preferred watershed size range. It is also possible to use terraces to add more watershed which two of my ponds do exactly that because at least my big pond was undersize without it.
My main pond thread that talks about it down the thread.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=355351 Edit: I just looked all through that thread and there is no aerial picture of the pond showing the terrace bringing in additional watershed. I know I have posted that picture but it may have been on someone else thread. I will come back here and post it when I find it.
