Well, the spillway's beginning to collapse and the back side of the dam is wet. Time to repair the dam and remove the 30+ year old trees on it. See photo.
Photo #3 is another neighbor (who's working on the dam for me) checking the water level remaining in the pond. We've let the pond down about 13 to 15 ft at the spillway by now and have another 4 to 5 ft to drop it to expose the pipe.
I see the water level is pretty low. Did you draw the level down to work on it? Why remove 30 year old trees? Were they on top of the dam and in the way or were they contributing to the collapse?
We've been dropping the water level for 2 weeks so we could begin work. The spillway is leaking internally and collapsing. The outflow pipe (installed in this dam 30 years ago) was used when it was put in and probably is 100 years old now. We'll see if it is any good but its ends and the dampness on the downstream side of the dam around the pipe is not good. Trees and their roots are damaging to earthen dams. DHEC requires you to remove them when doing major repairs (they can also take you to court and force you to remove them anytime).
Hayseed
The problem with trees on a dam is that the trees will eventually die. The roots will decay and leave a perfect tunnel for the water in your lake or pond to travel through. The water erodes the tunnel, making the hole bigger. Pretty soon you have no water in your pond/lake.
Is this the first time its been drained in the las 30years? If so, have you found anything cool on the bottom? [img]/forums/images/icons/grin.gif[/img]
About 7 to 8 years ago one of the lower boards broke on the spillway and the water came down roughly 10 feet. According to the neighbors, this is the first time in 30 years the pond has been drained. Not too much in the pond so far. Just a few tires, lots of stumps and Xmas trees. Bye the way, if you want to meet most of the neighbors in the surrounding area, just start a project like this and they'll all show up. Even climb around the barrier fences we errected and ask why they are there. I joked with my neighbor's son who's contracted for the dam repair that we ought to have a major project once a year just to get to know the neighbors. His eyes lite up with that thought ($$). [img]/forums/images/icons/grin.gif[/img] Sure do get lots of advice on what we should be doing. You'ld also think that fishing in the pond was a major source of food they way some complain about the pond going down now. (A few neighbors have access rights to the pond when the previous owner sold lots on one side.)
Met with the contractor and the spillway/pipe fabricator today. We walked to the base of the spillway and examined it. Cement block facing at the base is completely broken away and the pipe looks like the bottom has rusted away. Not surprising since that 48" pipe is estimated to be 100+ years old. The main topic of conversation was speculating about why the spillway was still standing. Most thought the drought probably extended it's life these last few years. Anyway, a new spillway with 100 ft pipe will cost in the $10,000 range for fabrication. [img]/forums/images/icons/frown.gif[/img] The dam itself will have to be recored and widened (since for half of it we've only found beach sand). Hopefully we hit some good clay soon.