Nice looking location for a pond. Have you seen how much water comes through there when it rains? Figuring out how much water you get will give you a better idea of how big you can make it. Bigger is always better with ponds. The more surface area you have, the more fish you can have. If you want to fish it, you need to decide what type of fish you want to have in there. Smaller ponds should only have one predator fish. Bass or catfish. One feeder type of fish like bluegill and minnows. Be sure to go deep enough to allow for evaporation and long periods of not getting any rain. Nothing worse then seeing your fish die because the water got too low for them to survive!!!! When digging the pond, make sure you make it ugly. Create ditches, drop offs, peaks and irregular shapes. Fish do not want a smooth, even bottom.
The dam itself is pretty easy to build. Just remember that it is held in place by gravity. The higher you build it, the more it weighs and the stronger it will be. If you want just a few feet or freeboard, then you need to go wider. From your picture, I'd make it wide enough to drive across and slow the sides with a 6:12 pitch.
How are you going to handle overflow? Water running over a dam will create erosion and wash it away. Going over virgin soil is good, but the sides of your hills make that kind of difficult. Pipes work, but they have a bad habbit of plugging up with floating debris over time, or not being big enough for the big storm and then the water goes over the top of the dam and washes it out. A concrete spillway over the top works, but it's costly and very labor intensive to create. It also has to be big enough to handle worse case situations.
Get rid of all the trees. It is easy now, and very difficult once the pond is built. You wont miss them, and you don't want them dropping leaves in there every year either. Ponds like sunshine!!!
What are you going to use to build the pond with? A pond this small is ideal for a dozer.
Eddie
