I currently have a small "frog" pond on my farm, about 2/10 of acre with no fish population, that has been there for probably 30 years or more. There are trees in the dam, some of which are probably 10"-12" in diameter. (Note - I am fortunate to be in an area where there is a high clay content to most soil and around here, it is rare for ponds to leak due to the soil. In fact, I am told that there are more farm ponds in my county than any other in the state, and a lot of that has to do with how easy it is hold water here.)
I am currently in the early stages of planning for a REAL pond, close to 3 acres and likely 20'+ depth. Here's the wrinkle...if I build the dam for the new pond where I want to, then it is likely that upper reaches of the new pond will rise to the base of the dam of the older, smaller pond...the one with trees on the dam now.
At one time, my plan was to punch a hole in the dam of the current pond and drain it prior to starting the build on the "downstream" dam, with the idea that I didn't want an old dam upstream of my new pond/dam. However, after reading through many posts here where people talk about nursery ponds and so forth...I now wonder if I could leave the old pond intact and use it as a nursery pond and also a sediment trap, although I really do not get any runoff as the watershed serving the pond is not tilled.
So, do I leave the old dam in and let the "new" water fill up to its' base...OR...do I play it safe and wipe out the old dam now, before building the new one down the way?
