I would like to excavate a 1-acre pond on our Kansas farm, and need some advice from the experts. It would be a kid recreation and fishing pond. I am a geologist by training. When you guys talk about "earth moving", I have a good grasp on the "earth" part and only basic knowledge of the "moving" part. (I have run a rental backhoe and mini-ex for small jobs on the farm, but don't have any experience running heavy equipment.) There is no waterway or ravine to dam, it will just be an excavation-type pond in the area where the soil runs to clay. There is a gentle slope (30'/mile). The surface is currently in tall-grass prairie. For the sake of discussion, consider a roughly square pond with each side measuring around 200' in length. Maximum depth would be 10'. Side slopes would range from 3:1 to 5:1. (For 3:1 slopes, the excavation would be 12,200 cu. yards) The good top soil goes to about 18". The next layer is loam clay from 1.5' to 6'. The bottom layer is dense blue clay from 6' to 14'. (I have only excavated test pits to a depth of 14'.) The top soil will be cut and stockpiled just beyond the boundaries of the spoils berm. The loam clay and blue clay will be spoiled in a berm that starts about 15' beyond the perimeter of the pond. We have a live creek on the property, so water will be pumped into the pond. The loam clay absolutely needs to be sealed for the pond to hold water. It contains thin sand layers that wept water into all of my test holes. The layers are obvious in the side walls of the trench. I believe the loam clay will seal well if it was disked and then compacted. (The moist loam clay will make a good ball in your hand, but you can feel some coarse sand in the clay.) I am still waiting for the analysis to come back of my soil samples. Question for the experts: What is the best way (or most efficient way) to seal the loam clay layer from 1.5' to 6' when the operator is already moving excess clay from the center of the pond across the perimeter to the spoils pile? I have seen how the good pond builders cut a core trench in the dam of an embankment-type pond. They then fill in 6" lifts and compact each lift. The equivalent process on my little pond would be a "core trench" with a total length of over 800'. This seems awfully long to me for a little 1-acre pond. I can envision starting a slope cut a little larger than the dimensions of the pond from 1.5' to a foot or two into the good blue clay. Scarify or disk the hell out of that slope, then compact with a padfoot roller under appropriate moisture conditions. I am pretty sure that will seal off all of the sand layers that would have leaked when the pond was filled. If that is the better procedure, then that leads me to many more questions: 1.) Should I put a few lifts of blue clay on top of my compacted slopes to provide greater confidence in achieving a good seal? (I think this blue clay will be very slick when wet. If adding a few lifts, I assume this would be done after the main excavation was almost complete.) 2.) What is the steepest slope allowed to safely operate a padfoot roller working side-ways along the slope? (I assume that would be more efficient in such a small space.) Or the answer may be that the roller only works straight up and down the slope. 3.) I am pretty sure I am going to have wet clay problems for at least some portion of the job. In wet conditions, does the dozer have better traction coming out of the center of the pond on well-compacted clay or on churned up clay? 4.) Would that size job be better suited for a D6 or D8? 5.) What blade type would you recommend for that job and material? Which track style, grousers, etc. if wet clay is my biggest concern? (Or just give an example of the preferred D6 configuration for the job, since there are so many options.) Further, I have seen jobs where the spoils are "finished" as an ugly block of clay with some grass seed thrown on top. I have also seen jobs where the operator does beautiful warping of the slopes, covers the clay with top soil, and has slopes that allow the grass to grow before the erosion gets started. Obviously, I prefer the latter. 6.) What is the best way to finish the spoils berm? What is the preferred slope? (The more gentle the slope, then the longer the dirt push from the center of the pond.) I DO NOT need to mow the berm. I am fine with the tall-grass prairie look. I will just mow the 15' band from the edge of the pond to the berm. 7.) Would the operator do a rough slope grade with his D6 dozer and then I cut to the final grade with a 5' box blade on my little tractor, AND then I spread all of the topsoil and perform the final grade? (That is a lot of work on a 32HP tractor.) Or is the excavation dozer capable of performing the final grade and then re-spreading the top soil with his much greater HP? 8.) What is the thickness of topsoil layer that is replaced over clay to re-establish healthy grass? I want to have a good design on this pond project BEFORE I talk to contractors. That way I can figure out which guys will do good work and which guys just dig holes. If it goes well, then I have room to add a couple more small ponds in the future. I would appreciate any advice from the people that have performed this type of work. Also, please point out all of the factors that I have not yet considered. Thanks, Rod
I think an excavator and a dozer to push and shape the material might be a good option especially if you have some wet/soft sections. A good dozer operator could get the finish grade pretty close you probably wouldn't need your tractor. I think you'd have to look into how deep it needs to be for fish and the requirements to stock it with fish. Here you can't just dig a pond and throw fish in it.
@Fishin'Rod This is a beautiful plan! I'd love to see pictures when you get started. I'm planning a similar type of pond (well a rebuild of my current pond) for a swimming hole but I'll end up using a liner for mine, I think, as I don't trust the clay content I have and I don't have the funds to not do all the work myself. You've obviously done a lot of thinking and planning and while I don't have any answers I'll certainly keep an eye out here. If you haven't you may want to check out pondboss.com it has a ton of good info, though it seems a little slow as of late... Good luck!
Bentonite clay can be used to seal your pond. Figure on adding 30" (2 1/2 acre*ft) of water to the pond per year. Keep your mouth shut about pumping creek water into your pond without a state permit, its not legal.
Welder Dave, thanks for the advice. I also think it will end up being a dozer AND excavator job. [I just didn't want to add any more complications to my very long initial post.] The bottom layer of blue clay is going to come out saturated with moisture. However, a scoop does not "run" any water when dumped. I think it is pretty close to 0% porosity. I also think it will almost certainly require ripping with a dozer - or just use an excavator. New question: How tough is it for the dozer to move clay like that from the excavator reach dump (right term?) to the spoils berm outside of the perimeter of the pond? I can easily imagine a slick, unworkable mess. I am not sure a de-watering trench and trash pump will work to create a workable job site. It may be a 2-stage job. Stockpile the topsoil and then strip the loam clay layer (like overburden). Come back to location during a dry August and work the blue clay to seal and finish the pond.
aighead, I agree about the treasure trove of information on Pond Boss. I have been a member there for many years. I am much more confident of my pond management skills than my "earth moving" knowledge! (I recently helped a guy transfer 250 hybrid striped bass and over 1,000 red-ear sunfish to other ponds. I have several buddies there that will help me fix my "fish" mistakes.) NRCS and the experts at Pond Boss agree that a pond in my geographic location requires a significant amount of depth to be at least 8'. (To avoid unwanted growth of bottom-rooted vegetation and initiation sites for filamentous algae.) The guidelines also call for a minimum depth of 8-10' to avoid fish kills during water drawdowns during the hot and dry months. My initial design is therefore a 10' target depth. I also plan to leave some dozer slots (or excavator slots) in the bottom that go down to 14'. That should give me a pretty good "safety" margin. [If I ever manage to break ground on the pond, then I will definitely post progress and photos on Pond Boss. I have the same nic over there.]
terex herder, thanks for the calculation on seepage and evaporation losses. That is pretty close to the calculation that I was using. Even bigger thanks for the "pumping creek water" warning. However, I have talked to the district guys from the Division of Water Resources. The water rights for my creek are already "over-subscribed" and I will never be allowed to perfect a water right. However, there is an exception in the regulations (K.S.A. 82a-728) to draw up to 15 acre-feet per year of surface water for "beneficial use", which includes ponds for recreation and non-commercial fish. "New" guys on any project always have an amazing capacity to "misunderstand" things in ways that baffle the old hands. There is certainly a fair chance that I did not understand correctly what the DWR people told me. I am planning to triple-check the creek water issue before I break ground. This project WILL NOT work if the pond can only collect surface flows from the drainage area above the pond. The soils are too permeable with a very high water infiltration rate.
I have the same handle on Pond Boss too. I was much more active over there but that fell off when I realized that my 5 year pond plan was probably closer to a 10 year plan. I'm looking at probably less than a quarter acre, but want to have a well for diving (and keeping fish alive, if I toss some in) that I hope to be in the 12-14' deep range. We'll see how mine goes and I've been harvesting mud from it for a couple years now, so I'll eventually get to the depth I'm looking for, then I just need to reform and seal it up. While I envy the clay you speak of I do not envy the mess that clay makes...
If the loam clay was / is leaching water into your discovery trench why do you need to seal it ? Worried about dry spells causing the pond to lose water into the loam then ? Can't the blue clay on the bottom be spread over the loam area are to seal it.
Tinkerer, my neighbor tried just digging out a pond, with essentially no compaction other than the dozer working. He deliberately excavated in an area with more sand, to get more water. The water came in his pond while digging and he only managed about 0.1 acres before getting the dozer out. The water level initially stabilized at about 1' above the top sand layer. By summer time, the water level was below the first sand layer and the side walls started sloughing in. By fall, it was a muddy mess with just a little water on the bottom. We even had decent rain that year. I speculate that the sands act as "low volume" springs. They have enough water volume to keep your job site wet, but once the finished pond starts suffering significant evaporation losses, the springs can no longer keep up and the pond goes dry. I intend to use the good blue clay from the bottom to seal the sides. I just wanted to ask the dirt guys about the best way to seal the side walls. If I was driving the dozer, I have no doubt that the feet travelled and fuel burned would be at least triple what an efficient operator could do!
I knew Kansas allowed 15 ac*ft of groundwater for homestead/stock water. I didn't realize that also included surface water. Your high water table makes it sound like this could be a project that has to wait for a long dry spell.
I dug my test pits when it was pretty dry, but there was still water coming in. I think it will be too wet to work, but the proposed site is the best location for a pond. Do you guys thing a 2-stage solution is the best option? Strip it to the blue clay and seal some of the upslope side just by pushing piles with the dozer. Let it dry, and come back in a year?
Cut a bench on the top of the blue clay to make a foothold for the clay that will be used to seal the loam. The loam should be over-dug to allow placement of clay to match the width of the bench. A safety bench is sometimes required in my area to prevent anyone from going into the pond and not be able to get out.
Thanks, Tinkerer. I knew the experienced guys would have a way to make things work better. If our compacted clay is really holding well against the bench, I wonder if we could even do some 2:1 slopes to further limit the weeds? [I also intend to install some areas with 5:1 slopes for kid and grandparent safety and spawning areas.] Anybody know the slope limitations for driving a vibratory padfoot roller? (Like a Cat CP34 size.)
I would strongly recommend NO 2:1 slopes ! They are bi## to cut with a dozer. Even a new dozer with nice high grousers ! They are a trap for animals and people to slip into the pond. That is why safety benches are created. I would go no steeper than 4:1 for a recreational use pond. 4:1 is a nice, easy slope to mow.
Tink, years ago I watched a hotshot gonna show me how to cut 1 1/2 to 1 with an 8H. You know you can't stay on it sideways, so he tried to run at an angle across it. That 8 just destroyed that slope pawing and scratching trying to go up and across at the same time. What a D!ck !!
When I get going on my pond I expect to have some benches also (I've called them shelves, underwater) but what about the slope from one bench to the next? I expect to have mostly escapable edges with a well to dive into, but my pond is much too small to go 4:1, even 3:1 is going to be a push, but with the shelves I think it should be manageable. Is it just one bench near the surface? I understand the inability to get a dozer on steep edges...
Every pond I was ever involved in was designed by a an engineering firm. A lot of them were borrow pits I never understood why they they were called "borrow" pits. We never took the material back that we removed. I have never cut a safety bench lower than six feet below the high water max. I never did a pond that had more than one bench. A bench for a foothold like I suggested to Fish'nRod would disappear after the clay liner above it is finished. I always cut benches a dozer blade wide level and horizontally into the slope all the way around a pond. Then just fill it and compact it with the liner clay. Sled Dog; Depends on the slope material as far as running sideways on 1 1/2:1 slope. I did miles of them with wide track D6's. If it is a heavy cut, then a D8 can do it no problem cause your gonna have a big windrow holding you. I will never forget getting on a steep slope with my first brand new D8N. It was the first to have differential steering. What a pleasure it was to use on those slopes.
1.5:1 Slope on a dozer sounds scary!
Tinkerer, Thanks, 2:1 slopes are out. No reason to do anything "difficult" on this pond. I did want to cut some benches in deeper water. Bass like vertical cover. For example, a brush pile against the side wall of a bench. I actually think slots that are the width of a dozer blade would work well for the fish. Is there a rule of thumb for maximum slot depth when working in a cohesive material (like solid clay)? For instance, 1/2 the height of the dozer blade? (I am just trying to make my final design easy to execute for the contractor.)
My experience is limited with clay liners, but I struggle to believe that you will be able to lay down liner clay on top of your wet, leaching loamy clay, much less get the water shut off. Maybe it's no big deal??
I think you over ex it all around so you are always laying the blue on the blue, right? Be sure to pay close attention to the bottom material. Your good blue is not bottomless, and it's a bugger when you punch a hole through to a draining layer. I'd want to check it all over for sufficient depth during construction. You could have it thin and never know till the pond drains out.
I can understand that working. In practice, you won't have any blue out in the spoils.
Benches that are down in the clay can be any height you want. Depends on how high you want it to be vertical on the up-slope side of the blade. Good thinking on your part about the fish habitat. I have been an avid fisherman since my Mom bought me a cane pole in the late 1940's ! A blade wide and the height of the blade would be good choice for fish habitat I think. Weighted down brush would make it even better. But, would be tough on fishing tackle ! In regards to the liner over the loam ; The loam has to be excavated back what ever distance you need for the sealing clay. Then cut the foothold bench for the clay. A good contractor should have thoughts of his own to help you execute your project. We have dug borrow pits in excess of 80 feet in my area and never saw the end of blue clay. Fishn'Rod is going to find out how deep his goes, for sure.
Tinkerer, "We have dug borrow pits in excess of 80 feet in my area and never saw the end of blue clay. Fishn'Rod is going to find out how deep his goes, for sure." "Once you find yourself in a hole, quit digging." If you guys see a post from me saying I am past 15', would somebody please send over a Cat to drag my dumba** out of the hole! I am going to put some brushpiles in the slots and at the ends, along with some other structure. There are going to be lots of floating markers over the "lure magnets". Hopefully that will ensure the kids don't bankrupt me running back and forth to Cabela's!
You exactly stated my reason for starting the thread - getting that seal is absolutely the "big deal". I hope it will work as proposed. If not, we may have do about 1/2 of the excavating, including cutting the benches around the shoreline - and then walk away for six months and lets the slopes weep water until they dry out. The location is pretty flat and I have a good riparian buffer of healthy tallgrass prairie between the dig site and the creek. I think the spoil piles should survive, but any further advice on "best practices" is always appreciated!
Shimmy, I don't understand this comment, but I am not an operator. "In practice, you won't have any blue out in the spoils." After we cut the shoreline benches to a depth of roughly 6', we will still be excavating the center of the pond to 8-12' with a few slots to 14'. That is the source of the sealing liner clay. If I am failing to understand your concern, could you reply again and explain what potential problem I may be missing? Thanks, Rod
skyking, I believe I can still get some more soil cores drilled by the NRCS before I use up my quota. I think their little rig goes down to 25'. I definitely want to find the bottom of the blue clay. My plan was: talk to you guys and find out all of the problems I don't even know about, pick my best location, take more samples, and then review the layers and soil components. I am sure my initial plan will run into some problems. I will probably come back here in six months to get a little more advice for Plan B! Thanks everyone!
I guess I'm imagining a bowl if you will, the bottom half filled with playdough, and the top filled with sugar. After you get the sugar out, you are going to spread out the playdough over the entire inside surface of the bowl. Crude description probably, but best way to explain what I'm thinking.
And to further clarify, you would use all the "playdough" covering the inside surface of the bowl, with none left over.
Thanks. I guess if I screw up on material calculations or the layers change unpredictably, then I might need a borrow pit for more material. I guess I can then use the borrow pit for a forage pond for baitfish production - you know, turn lemons into lemonade!
Tink, care to elaborate further on this procedure? I can draw it out if necessary, but have a project this summer that might test my knowledge and experience. The engineer is suggesting that it's possible to place a clay liner over water-bearing sand and gravel. Profile goes like this: 0-1' Topsoil 1-2' Fat clay 2-6'. Semi-coarse sand/gravel. Current water table 3' 6-60' Shale clay with water layers The suggested plan is to excavate down to the shale clay, and over-excavate the perimeter enough for a 2' thick clay liner. I have tried to stop water before, and have never been successful using clay to stop water. The water always is able to saturate the clay no matter how you lay it in.
Take off the topsoil (loam) several wide all around the pond until you hit good clay. A dozer blade width is fast and easy. Then fill it back in with structural clay. Doing that will establish a clay cap and the clay will be continuous all the way from the top to the bottom of the pond. It only takes a few inches of topsoil over the cap to grow grass. We always compacted the clay with a sheepsfoot roller. Tracking it in with a dozer is a guarantee to have leakage. Not all clay is the same that I ever worked with. Some types would never seal. They required bentonite to seal them. Bentonite may be a solution to the clay that you are worried about leaking. A long time ago there was a lengthy discussion on HEF about it. I have extensive experience Bentonite.
There isn't any good clay.
The clay that is to be used for a liner has to come from 1.5 miles away from the pond site. Sand/gravel full of water at 2'. Slimy, wet, shale clay (that's what the engineer calls it) at about 7'. You believe that it's possible to hold back 3-4' of water table with just clay? Is it possible to get the entire area capped without dewatering?
I worked at a golf course that had 2 irrigation ponds dug that used custom made liners. They dug a trench around the ponds to hold the liners in place and then put a layer of gravel over the liner to protect it from getting damaged. Larger rocks were then placed about 8 feet wide around the perimeter of the ponds. Ponds won't leak or grow any weeds.
It's that sheepsfoot packing that will keep me from doing a real clay liner in my pond (assuming I ever get to it) and why I'll go the route Welder Dave mentions. The amount of layering, and packing, and layering, and packing, if there isn't good clay already there, is pretty intimidating to me. We have decent clay in certain areas of my pond as it is, but not enough stable enough to keep it from leaking for whatever reason. My guess is the trees growing on the perimeter of the pond aren't helping. Mine has water in it, in spots, year round, but it fluctuates probably 4 or 5 feet every year. No good. I want to be able to trust that I won't have leaks and not have to worry about bringing in crazy equipment, so I'll go the liner route. If I had tons of money maybe I'd try to get the right clay in, but if I had tons of money it'd be done already. My concern with a liner is the pond is loaded with those little peeper frogs and some turtles and I'd love to continue having them. Covering their homes with a liner makes me think I may kill them all, or at least uninvite them. My plan is to eventually have good plant and gravel filtration so I can swim in the pond, so there'll likely be dirt on top of the liner but I don't know...
Shimmy1 ; What is the pond going to be used for if you need to seal the water from entering it ? Whatever is in pond would exert pressure against the clay liner and that wet clay seam. I have no idea if it would be enough to prevent failure of the clay liner. The ponds I worked on had liners to prevent fluid from leaving it. I worked on quite few water retention ponds and they were never lined. I worked on new garbage dumps. They had welded poly liners installed and then we lined them with clay to protect the liner. aighead ; If you use a poly liner to seal your pond you will need some way to supply water to it or it will never stay full unless you have lot of rainfall year around. I doubt very much if clay was installed over a poly liner that it would stay in place. That stuff is unbelievably slippery. All the ponds i worked on had either outfall pipe installed or a ditch to prevent it from being overfilled and creating uncontrolled erosion.
Feedlot runoff. I understand the concept that once the pond has water in it, the weight of the water will stabilize the liner. What I don't know, however, is how do you lay out structural clay at the proper moisture, and get it compacted before the ground water screws everything up? The liner is going to be 2' thick. That will be 4 lifts that have to be nuked. The water table is about 4' above the starting grade of the pond bottom.
I was involved in a building a couple ponds that had a similar situation as yours. We had to drive sand points around one of them to dewater the gravel seam. Electrical service was run to them and an electric sump pump was run 24/7. Another pond with the same situation --- we dug a trench all the way around it and used a 4 inch sump 24/7 to dewater the gravel. Both methods worked quite well. The sand in the trench we dug was very abrasive to the pump impeller. It wears them out way sooner than normal. The pump did run a long time before the water in the trench started to rise because of the worn impeller.
As it stands now my pond catches probably 90% of the water that hits my front yard, so everything you see here, in front of the house, plus there is a creek along the top of the picture I could harvest from, if I'd like. I would not do clay on top of liner, I'd have dirt and likely more gravel than anything. You can see pretty clearly, in this picture, where I've done some digging with the backhoe, I wish it reached out a little further.
Just to clarify, when we talk about a clay liner, we are referring to a blanket of structural clay, that is all. Nothing manmade. You over-excavate the pond to allow for building back 2' thick layer of clay. This has to be laid 6" at a time, at a relatively perfect moisture content, and mechanically compacted to 95-98%. This is why the groundwater is such a problem. Any water leaching from the ground will make it impossible to keep the liner clay uniform.
You certainly know what you are dealing with, Shimmy. Do you intend to pump the feedlot runoff out of the pond ? If you did that, there would be a lot of water pressure pushing against the liner. Especially towards the bottom. I'm wondering if 2 feet of clay would be enough. We placed 7 feet clay in the garbage dumps. They had 3:1 slopes.
This is all new construction. Nothing has been excavated yet. Only test pits to establish the soil profile. That's why I'm asking around here. I believe the only way to install this liner is to have every bit of ground water removed from this area, keep it out until the liner has been approved, and then fill the pond with water to at least close to the estimated water table? Oh, and did I mention this pond is going to be around 80' wide and 300' long at the bottom? I'm thinking a perimeter trench like you talked about might be the only way to go. I have considered proposing to backfill that trench all the way to the surface, compacting from the bottom up with the clay we intend to use for the liner, and then digging a few trenches inside to dewater. That way I won't have a damn moat to contend with during construction?
That is exactly the way I would do it. I guess if the clay fill in the trench failed to hold the water back you could always dig out. But I wouldn't back-fill the trench until the pond is done. One nasty rainstorm could be a disaster. IMHO. Consider using Bentonite mixed with wet clay to backfill the trench. I was involved in creating thousands of feet of barrier trenches around old garbage dumps. We used to dig a small pond and dumped the Bentonite and clay in it. Then add enough water to make a very thick slurry water. I would go into the pond with a D8N and track back and forth to mix it all together. It was helluva mess and tough on the dozer undercarriage. There were times the slurry was so deep that the alternator on the dozer would get submerged. When I had the slurry prepped an operator on a 973 would go into the mess and load it into trucks. You could have a water problem if you backfill the trench before the pond is done. A couple of culverts in the bottom of the trench covered with clay would give you access to the pond. 80' x300' is a big pond. 3:1 slopes ? Or a little flatter ? The garbage dumps I worked in were several times bigger than that.
Curious why they wouldn't use an excavator to mix and/or load it?
I expect 3:1 slopes