I am going to build a pond in some clay soil. I have built ponds in the past in sandy/rocky soil, and I was wondering if you do it any different. Normally I would clear it if need be, then dig the core. I then start digging the pond out and building the dam. I generally take the core down to solid rock and then start the dam, by filling it in 6 to 8 inch lifts and packing. My questions are how deep to take the core? Do I need to pack the bottom and sides of the pond? Thanks
Only need to take the core down 2' or so just make sure its has a good clay bottom. You may have to compact it so it doesn't leak. Might also bring 1' of good clay in to line the sides and bottom if you have any seems of sand or ETC.
Clay is generally pretty forgiving when building a pond or lake . Limestone can be an issue in my area as it is porous and leaks can develop later . When building one in an area where limestone is present I do as Dozerboy suggested , over dig the bottom then bring back 1to 2 feet of clay packing it back in . Farm tractor works good for packing also . Now sandstone seems to hold water pretty good . For myself the depth of the keyway varies depending on size of dam & terrain . For me most of the time its between 5 to 8 feet deep . In the first picture I was digging keyway on a small pond . It will look like a V ditch when finished digging then if the material looks good I bring it back & pack it in . With the V ditch contour in the bottom it pretty much "wedges" back in as you are packing in lifts . Other pictures was a keyway on a 2.5 acre lake . It was around 8 foot deep , I started digging the first 4 feet with the scraper then used the excavator for the rest . One reason I go that deep is many times there is old field tile in the project and I want to make Damn sure we get it all out . Old Allis Chalmers narrow front WD-45 works great for packing in the key way .
Yair . . . Here in Australia most dozer built embankments have no cut off or keyway. I push off the topsoil and mark offsets for the centreline and start pushing. Occasionally there is the luxury of working in clay but for the most part (in this district) clay or claylike material is in very short supply. The country is often sand or sandy loam on top of (if you are lucky) eighteen inches of clay and then hard granite rock. The bank is shaped with sand and then lined with clay to a little over full supply (by wash) level . . . the last couple I have done I was scratching to get enough clay to a get ten or twelve inch coverage. The material is well track rolled and then the topsoil with it's seed bank is pushed up to get a good cover on the downstream face, over the crest and allowed to trickle down the inside. Such methods are not ideal, but, for the most part the structures work. No guarantees are implied or given and really this is the only cost effective way of providing stock water in a region pretty much devoid of underground supplies. Fifty hours with a 150hp dozer will result in a pretty decent hole. Cheers
Wow, the work looks pretty brutal. I think the complete work would take more than 1 or 2 months maybe correct me if I am wrong.
I sure do appreciate the advice. I really like packing with the old Allis:thumbsup
One of the biggest thing when punching a pond in clay is to get a good topsoil cover on the dam faces. Clay swells and contracts when it gets wet. This results in what starts as small cracks, but will lead to leaking cracks that will cause a dam failure over time. I usually don't pack the bottom and sides unless I have to add clay fill over sand, rock, or something of that sort. John
I'm no soil engineer, but a V ditch for a keyway would be a NO NO from my understanding. As deep as you are going probably doesn't matter.
Yeah ... We like it to .It runs like a champ , I really need to paint it. With the narrow front it works great for packing in the keyway in the first stage . Then after most of the V ditch is filled & compacted I jump in with a wide front G 1000 Moline & box blade . While the WD Allis was in the keyway , the excavator had just got done bailing out where the old waterway was . It had drain tile in it plus the material was pretty muddy so we dipped it out and put in some good clay & packed it in with the WD 45 . It's somewhat of a time consuming process but the way I look at it is the Keyway is important being the foundation of the dam . On the 2.5 acre lake project I would have spent about a week digging in & building the keyway . Best of luck building the pond project & building the dam jhyder and keep us posted .
I am looking to have a dam repaired on a 1/3 acre pond. The soil is mostly clay in Indiana, but I know dam leaks can be an issue over time. I also understand that bentonite has been used in the past to seal up or line ponds. Not too concerned about 3 of the sides leaking, but has anyone ever put in a layer of bentonite at the dam area as an extra measure of long-term protection?
just my 2 bits but chuck we just did a job that had good plasticity index of clay but the developer has contractor bentonite pond anyway because of pond leakage problems in the past so just for insurance they bentonite them and also put 6 inches of top soil over bentonite and clay. If pond don't fill up right away the sun dries the clay out and as already mentioned it cracks and water seeps down those cracks had to go fix ponds on 2 different jobs because of that! Jerry
before I invested a lot in bentonite I'd determine why it's leaking... In my local area 90% of dam leaks are from muskrats boring into the dam. Bentonite wont stop them. They bore a "water side" hole and then dig out their den to where it fills partly with water, they then dig out an escape route above ground. Water softens the spot they dug out and the clay core begins to swell and contract. This allows the water to move farther and farther in until it leaks out the back. When the water level drops they do it again... The best cure is to spray everything green around the pond to drive them off to a new food source, then excavate the soft spots and holes and fill back with compactable fill and dress with top soil. They are expensive destructive little ****ers!!! John
Yeah JD8875 , muskrats sure can cause some damage to a pond dam . Many times finding the leak is half the battle . On a few occasions in limestone country I have seen a hole just suddenly open up draining a pond down to it's level overnight . Might be 2 to 6 inches in diameter ,looks like a giant crawdad hole only it's a sink hole leading deep in to a limestone cavern . I have had some success repairing them buy digging it out say 4 to 6 feet deep . Then go to the woods & scoop up a pile of leaves ,twigs ,rocks , ect . I then fill the hole in layers , first the tree leaves & debris then a layer of clay dirt on top then another dose of leaves & twigs & so on until the hole is full . The leaves & debris help stop up the hole & keep the dirt in place much like a beaver dam works . We have a pond that has a slow leak in it now that I'm thinking about spreading bentonite on the water surface & see what happens . It's about 30 years old and used to go completely dry . We narrowed down the big leak at the water system it had going to a livestock tank . While the pond was dry I took the dozer and cut a new keyway at the toe of the dam on the inside of the pond . While doing that found the 1-1/2 pvc pipe going through the dam & cut it off and plugged it off . Dug down another 5 feet below the pipe with the dozer in the keyway then got some good clay to pack it all back in . Pond filled up ok but we still noticed a slow leak . I then fired up the old Insley crane with wrecking ball, backed it out on the dam and pounded the pond floor out as far as I could reach . http://s1016.photobucket.com/user/td25c/media/007_zps04b32c39.mp4.html?sort=3&o=0 The leak in the pond is tolerable now and it has some nice fish in it so I'm thinking about trying the bentonite on top of the water . www.pondsealer.net/#/welcome/welcome www.sturgismaterials.com/products-view/sodium-bentonite/