Gully Washer: I was thinking about your first drawing and putting a few pipes I could set-up like a culvert system and thought about the dam erosion too. The diagonal in your second drawing would be tough to install with compacting the soil and the flow could be so fast I would need a huge slab or I'd end up with an eroded hole at the end behind the dam. I definitely need the dam to act as a road to access land I want to clear and access.

For the time being and due to so much rain (nearly everyday for the last 5 weeks) I am starting to clear paths with my small tractor around the area to see the lay of the land. The area is extremely overgrown and I'm not sure what is natural grade and what is remnants from the clay mining operation 125+ years ago on this property. I'm trying to save any oaks over 18" diameter but all the rest are gum, pines and dense overgrowth that have to go and burn.

The condition is very confusing: The valley is about a quarter mile long with about 80' drop and 30deg slopes on both sides. Water is running about 1/3 the way down at the top, then it goes away and reappears for the last 1/3 and then in goes through a 5' culvert under train tracks and off my property. I want to build the pond at about 1/2 way down the valley where much is dry. I assume I have some underground cavern where no water flows at the surface. The areas where water runs is a 4'deep by 3' wide trench worn from the water flowing over years. There is no trench where water doesn't flow of which most would be at the bottom of the pond. I'm thinking I will need to excavate the valley under the pond site to the elevation at the bottom of the trench and I'll open the cavern.

The train track itself is about 20' above the 5' culvert at the bottom of the valley which is another interesting situation. In essence the track structure is on a dam but with the huge masonry culvert at the base. I expect if my dam ever breaks the land would flood but their culvert would drain it down pretty quick and the land on the other side is vacant.

I shot elevations the other day to see where a waterline would be at the perimeter of my proposed pond site. Looks like for a 1/2 acre pond and with the excavation the water would be 16' deep at the dam. The other option for 1 acre it would be 24'+ deep at the dam.

The water flow is about 2-3 gallons a minute now (its been running consistent for the past 6 months or more) but in droughts it doesn't run so I am counting on runoff to keep it full. I have about 20 acres of runoff land that would flow to the pond site so that is an unknown how much rain we'll get and how consistent it will be but expect that is always a risk.

For now it looks like I need to just clear trees, brush and roots until I open up the area and then re-think the dam/overflow design based on findings. I can't get the big equipment down there until it dries out some. With all this rain I wish I was further along and the darn thing would be full.

Esshup: I don't think I have any beaver in the area but am concerned with tree branches clogging the open top inlet. My fathers pond did that a few times after big storms and it was a fight to hurry and untangle the mess from a boat. His was literally out in the water though and I was considering burying most of the riser in the dam face and putting a ramp to it from the dam. I am still researching and every method is open at the moment.

I'll get pictures when this progresses but have to clear other land and fence it for pastures first and I have a day job that seems to always get in the way.