Pond Boss Forums POND CONSTRUCTION Soil questions daming up a large valley?

Hello everyone, new to forum but have been reading the great advice for a year or so..have built a few ponds but never expected to run into these factors..in fact i thought it would be the easiest pond project yet,but has turned out to be a very time consuming and difficult project to say the least..I have sold all of my equipment so a friend of mine comes up with the idea of daming a large valley to create a pond...one side of the valley is accessible with a track loader..the other barely accessible on foot...this pond has been his dream so i took off on it..cut the large post oak trees down in the inaccessible side..on the other got to work with the loader..as i dug through gravel about a foot i began to hit nice red sticky clay..after about 2 foot of clay rock...missouri shelf rock..then 2 more feet to solid slate..slate is easily broke up with a backhoe breaker for digging trench core..the inaccessible side is huge rock and rock shelving...as i was digging with loader water began to seap up from the ground but has to be dug out to even have water in the shallow side..at his request i will dam it up but i have many doubts about it..any words or thoughts? thanks

Welcome! Just off the top of my head, unless there is sufficient amounts of clay available to plate over the porus areas, he'll be hard pressed to hold water. Especially if it will see much depth. (more depth = more pressure to leak out)

Yep!

Thanks for the words,,i believe i can put enough clay on the pourous areas , its the side that is not accessible that worries me,its basically undisturbed.. this is a 1.5-2 acre pond with a spring from way up the hill running into it..water volume is low during summer months..clay is available from other parts of the land,yet more expense getting it to the pond..wont the pressure of the water send water out through cracks in the innaccessible side?and where does it go? i see no indication that water comes out below the dam except from this spring that will run through the middle of the pond..probably looking at 15 ft to 18 ft total..it looks as though he is ready to dam it up and see what happens..i will obviously put in a bottom drain so it can be drained to do over when it dosent hold..but i will (under protest) move ahead on it...thanks for your advice..any helpful tips are sure welcomed..i will use all the help i can get to assure i have done my part..

The water, if it gets into any fissures on the opposite side will travel downward and laterally, moving from higher pressure areas (in the pond) to lower pressure areas. The water could even move vertically, but only to the level that the pressure equals out. It will wick up and around the pond edges, which is normal until the ground is saturated.

If the ground slopes away in the ravine, you could also put in a siphon drain.

thanks esshup for the comments...we are moving ahead on it ...will keep you posted......