Pond Boss Forums POND CONSTRUCTION Building a dam Repair of washed out dam

Hi,
Please help! I'm starting to repair a 40 year old, 1.5 to 2 acre washed out pond. The cause of the washout is undetermined, could be from water overflow or trees by the overflow pipe. The water shed is around 100-120 acres with 30 in. of annual rainfall.

My dilemma is the dam has 30+ trees along its entire distance. Do I remove them and take the dam down to the core. OR should I just repair the washout by the overflow pipe? I'm concerned that if I just remove the trees, their deep roots will rot out and cause a continious leak.

Your advice would be greatly appreciated.
Merry Christmas,
Mark

Rule of thumb has always been to cut/remove any tree 6" in diameter or smaller.

If it were me and I were going to the trouble of repairing the dam I would dig up the stumps of all trees on the dam.

Rebuilding the whole dam I wouldn't think would be necessary.

If I were going to do it, I'd go ahead and do it right.

Thanks Ric, for your reply. Sorry I didn’t get back to you sooner, but I’ve been dealing with Prostate Cancer. (I would highly recommend the DaVinci Robotic Prostatectomy, for those of you who are dealing with prostate cancer. I’m 51 yrs old, PSA of 2.5-3.1, & normal sized prostate! If you have any questions, email me. I also take Personal Messages.)
We found why the old dam washed out, it had never been cored. They had just pushed the dam material on the top of the soil.
We removed all the trees, (6-20” in diameter), and the roots as best we could. Then we dug a new core on the face of the old dam and through the washed out area; filled with clay & packed with a sheep’s foot & scraper. The pond filled in May, and so far no leaks! Hopefully. the roots we missed won’t present a problem when they rot! I will keep you posted.
Mark

Hi Mark,I'm new here. I am trying to rebuild my dam on my pond and have been learning all sorts of new terms. What does "coring" mean? I need to make some decisions on my dam and want to make sure I know what steps to take.

Also, sorry about the prostate cancer. I hope you are making it ok.

DC, coring is kinda hard to explain without drawing a picture. Essentially, it involves using a dozer to dig a core trench in the natural earth that will be the sides of the dam, down through the bottom area. Then, filling that/those areas in with clay and packing the heck out of. It ties the dam sides and bottom together. The alternative is to just start digging dirt from the bottom area and pushing it up next to the sides. That can and often does allow leaks between where the new dirt is pushed and the natural sides. If I haven't adequately explained it, send me an E-mail with your address and I'll draw a picture.

Another term that you could use for this process (that you may be more familiar with) would be a "keyway". By just piling up new dirt onto existing grade, you moreless create a cold joint that may leak in the future.