Originally Posted by shaman
Originally Posted by IZH27
Is the branch slate bottom? If so a “key hole” cut will need to be made across the slate to keep water from seeping underneath. I had an amazingly strong spring and was considering a nice pond when I lived in Adair. I fixed that urge by selling the property. :-)



This is in the Trans-Bluegrass, north of Lexington. It's all limestone and clay. The clay is so impermeable that we all have to have ponds instead of leach fields for our sewage. The problem lies in the limestone-- if there's a gap, it can leak badly. Most recently, two locals have tried ponds. One went perfect. The other failed to hold water in the test dig and the project was abandoned. The two ponds are less than 1/4 mile apart, and to the eyeball looked identical.



In that case, you should dig out the dam/ key way first to see if you can hold water at the dam. If you are building in a natural ravine you can always pack clay over any area that might show limestone. We hit sand when we were digging my dam. This was after all the trees and roots were removed. I ended up mining about 30 truckloads of sand and plugging the seam with clay. Added about 5k to the job. I believe if you go over 25’ high at the dam or 3/4 of an acre in surface area you will need permits and permission.
Here we are packing clay in the keyway under the dam.
[Linked Image]

Last edited by Toddly; 09/04/19.