Pond Boss Forums POND CONSTRUCTION Soil questions Healer, heal thyself

Calling all dirt-guys...
Hey Tn Hillbilly, Dirtguy, Meadowlark (I'm shinin' the dozer sillouhette into the nite sky!), Bob or and any other PB'er with dirt in their teeth.
Let's talk core...my core. Last summer, after clearing a ton of timber for the pondsite, one of the last things my excavator did before wrapping it up for 2005 was to cut a portion of the core at the damsite (we stopped the project here so I could catch my $ breath and think a whole bunch 'til summer '06 to complete). When they did so, I thought I kinda understood what they were doin', but then maybe I didn't. I just spent 4 hours this early a.m. (in 5 degrees + w/c) with him discussing a bunch of new twists and ideas that I have for the project. Then I asked him to explain, again, what they were doing with core.
He said that the portion that they dug, in the very center-bottom of the valley where the dam will lie, is now complete and will not be re-disturbed. (by the way, the entire length of the dig was about 75' long; the dam will be about 265' long at the top, stretching across a perfect valley). He said that it gives them a small head start and a look at the soil to verify the previous test hole. I said "is that it?" He said no...that's why we staked the short area that we did. We will come back this summer and pick up at both sides, completing out to the ends of the dam. I told him I thought a core was constructed all at once, packing a layer at a time from one end to the other. He said no, that the main reason for the core was to cut across the path to disrupt any potential for piping within the subsoil. I added that I was concerned that he did not remove the layer of topsoil when he rolled it back in. He responded that the blend of the t-s and clay was a non-issue and besides, the soil tends to go back in at the order is was removed, more or less, with the best clay at the bottom anyway. I was having some issues with his wisdom and he knew it. He assured me that this is exactly the procedure he follows for all his embankment ponds without failure over 20 some years.
NOTES: I trust him implicitly. He comes highly recommended, has done many ponds in the area, was the NRCS agent in this county before he started excavating, and has done nothing less than make me feel like my project is his own. This is the first time I have even questioned him as his presentation and work is so impeccable. I am posting 5 pic's that kinda show the progress of this core section. If you are like me and in an area that doesn't yet have hi-speed, go get a cup of coffee or just change the channel.






I should also add that he said that he would have no problem if I want him to dig it all back up again and re-pack it as one long core when get to diggin' this summer.

The design of your core trench looks fine to me. The topsoil layer however looks pretty sandy in the pictures. If it is sandy, make sure the core cuts if off all the way across the dam. I have seen a number of ponds leak because a porous layer was not cut completely off.

Brettski, I've never run a dozer but have a leaky dam on one of my ponds due to not having my dam cored. I didn't know to insist on it at the time it was built.

Essentially, a core should be cut through one side, down through the bottom, as he has partially done and through the other side. It should be one continous trench. Then it should be packed with good clay.

I've been asked about a core on several occasions and have a problem verbalizing it. Once you see it done, it makes perfect sense. An internet search has not given me a good picture that I can relay. Maybe someone else can find a good illustration. Can anyone post one that they have?

By way of illustration. Get three wood blocks. Place two vertically to represent the sides of your valley. Then place the other horizontally between the other two to represent the bottom of the valley. That will somewhat, figuratively, represent what you are starting with prior to doing any dozer work. Now take a fitted piece of plywood and wedge it between the 2 vertical sides and down to the horizontal block. This will represent the dirt that will be used on your uncored dam. The weak or potentially leaky spots is where the plywood meets the horizontal and vertical blocks.

Now cut slots in all three blocks and push the plywood down into the slots. This ties the plywood (your dam) to the 3 blocks. See the difference in the fit?

The same concept applies to completely coring a new dam. It should be cut through both sides and down through the bottom. A lot of leaks occur where new dirt is stuffed next to existing dirt.

Think about it. A glass aquarium holds water because the sides are glued together. However, you really can't apply any kind of glue to dirt. Thus, the whole thing, when properly done, is cored to tie all of the 3 pieces together to prevent leaks.

Brettski,

I'm talking with ZERO dam building experience but I would of thought a core would be one continuous band of material from one end of the dam to the other.

Thanks for posting the pictures and please keep us updated.

Nice woodworking analogy, DD - the core trench as a dado!

I just got a mental picture of Norm Abrams on a dozer.

Brettski,

I have to ask. If the dirt that came out of the trench was put back in, why dig a trench in the first place? The main reason to excavate a trench is to replace the dirt that was removed with good clay dirt to effect a seal. If the dirt is good clay anyway, why remove it? Another point. If you are going to pack the trench with a dozer, it needs to be at least twice as wide as the dozer, otherwise, how do you ever get a track on top of the center of the trench? If the trench is cut as wide as the dozer, you need a roller to pack it.

Bettski,

Have him push all the top dirt out of the way for dam construction, once the dam is complete, use it to dress the dam. I suspect that he is just pulling your leg, and thinks you don't really even need a trench, otherwise why do that little bit of work on it, without removing the top dirt? All of the top dirt should be removed from the entire dam site, not just the trench.

DD1...thanks for the quick response. I am pretty much past core-101, but truly appreciate the concern. Your subsequent point regarding a continuous, monolithic seam is right where I am gettin' stuck with this contractor's approach. Follow me...
TnH...You responded as I expected, and it does not fall on deaf ears. That's why I solicited it...I want all definitive postures on the table as I decide a course of action (or reaction). I am not going to question his decision to cut a core, even if that clay down there appears to be in excellent condition, based on sampling. His decision to do so is to make absoulutely sure that there is no unseen seams, lenses, or piping thru the entire length of the dam. We can debate this decision, but it will be moot for this project. OK, so the core is gonna happen. This is where I climb on board with you. If you are gonna pack a core, everything I have learned to this point is specific application of the best clay substrate available thru the entire mass...period. I was also taught that it is best applied by a methodical layering and compaction thru the entire length of the dam. (Meadowlark would disagree with the this...I respect his posture). I also had the same thoughts regarding tracking it in on a one-blade wide trench, but will admit that I have had more than one NRCS agent tell me that this practice would be acceptable. Pub 590 stays fundamental by saying a core trench the width of the blade at 8' min is fine, then goes on to say that thorough compaction should occur in layers 9" thick...no mention of the equipment. As I noted at the end of the pics, he said that he would have no problem with pushing it all out and doing it at once...not being a wise guy or pulling my leg but sincerely wanting to cooperate with my desires so long as they don't compromise what he considers good practice. I already anticipate pursuing this option. This dam site is backed up into a corner of the property and the valley behind it is about 1 ac. The plan is to waste about 12,000 cu yards back there, taken from in front of the dam and filling in the valley behind to create a very nice gentle slope behind the dam...in the range of 14-1. The silty clay topsoil is about 30" thick at the base of the valley and diminishes to 12" at the upper edges. The clay below is excellent and goes a long way. We pulled a sample 13 feet down and it doesn't stop. I pulled the well drilling records for 4 wells surrounding (all within 2000 ft) and they show 2 ft of t-s, then 30 feet of blue, yellow, or gray clay. There is a 450 ac hunt club across the street from me. There are 6 ponds on it, up to 6 ac. He built 5 of them. 2 years ago, he just finished a 2 ac that goes 20 ft deep at the dam. It's a beauty.

If you are going to remove all topsoil from the pond basin to the centerline of the dam I wouldn't worry about a core trench. If he plans on wasting dirt (topsoil/silt) on both the front and backslope then yes I would do a core trench with a clay centerline.

Is he planning on doing the whole project with just the dozer? Or will he also use the trackhoe/haultrucks, scrapers?

Several issues strike me here. First, the purpose of a core trench is to create an underground waterproof barrier, similar to a vertical wall of compacted, processed dirt. Key word here is 'processed.' Otto has explained to me many times, shown it to me many more times. Look at the top photo and notice the layers of soil, down to clay. Pushing or excavating the dirt from the core trench, then 'processing' the dirt simply means to mix the dirt with an adequate amount of clay to make it compactible. Then, the pulverized, mixed 'processed' dirt is returned to the trench and compacted in layers, usually six to nine inches at a time. Unless the local soil is too porous, or there's not enough clay to mix, the soil removed from the trench is acceptable to put back in it, as long as it's mixed well and compacted properly. That's why core trenches are wide, so heavy equipment can get in there to compact the returning soils. Compaction is done with a sheepsfoot roller or loaded rubber tired scraper. Bulldozers aren't heavy enough. The core trench should be long enough, and deep enough, to create that underground barrier needed to minimize seepage. So, as long as the core trench does that, and the dam is built on a strong clay foundation, you should be fine.

"Pub 590 stays fundamental by saying a core trench the width of the blade at 8' min is fine, then goes on to say that thorough compaction should occur in layers 9" thick...no mention of the equipment."

The key phrase there is 'thorough compaction' Can't get that with a dozer. I wish I had your money Brettski! Wait, I wish I had your contractor's money!

One thing about 'processed' dirt. That's the kind an excavator makes money on. The more dirt you 'process' the more the excavator makes on a given job.

TN H,
I think Bob is refering to processed dirt as the mixing of availible materials to acheive a substance that will compact properly.

Tn H states:
That's the reason I reached out to you...for your respected opinion. I have a window here to adjust at virtually no loss.
Tn H adds:
ouch.

Bob,
Thanks for kickin' in. My guy was making that exact point regarding "processed" soil as he was explaining it to me...just a different delivery. It was this point that concerned me since all I have been exposed to speaks of the importance of good clay as a core structure. I assumed that it meant going down 30", extracting the real good stuff, and packing only that virgin clay into the core. I am sure that his method of rolling it back in is his "processing" procedure of a soil type that is very common in this region. As mentioned, this guy has big success in the area as a pond builder. If I read you right, this processing method can be acceptable if the final mix is acceptable.
I still maintain concern for two main points beyond this. a) performing the coring operation in seamless strokes across the entire core, end to end b) proper compaction. He operates with a back-hoe, D6 hi track, and an earth mover. I am certain that his immediate plan does not include specific compaction equipment. Is it out of the question to increase the width of the core to 1-1/2 blade widths and track it in with the D-6, by tracking side, center, other side? What do you think of the practice of doing the center/valley first, then coming back to do the edges and up later? It bothers me. Also as mentioned, he knew it and will have no problem recutting this center section and doing it all at once if that's what I want. I have 30 minutes of dozer time on the core work they have already done...zip cost.

Brettski,

Just kidding about the money. I know it costs a lot and you are intent on doing it right, obviously. I suspect that by the time it's said and done you could have owned that dozer in the pictures. I can tell from the pics it will be a beautiful sight when finished.

What I see as an injun ear and amatuer dozer operator is this. Let's assume you let the contractor come back in and work the ditch as two seperate pieces joining what he has already completed. Since a dozer has to dig itself in on a ramp, no longer than the trench he has already dug is, he will have to dig virtually all of it back out just to get the dozer down to the elevation of the original ditch, to start the new ditches. Call me suspicious, but this tells me that the trench work he did was nearly 100% unproductive and leads me to believe he was just burning what money you told him you had to spend until he had to pull out. You do need to insist though, that they use a roller of some sort to put it back in, that dozer just ain't going to get it. I'd defer to the 'proper compaction' statement in Pub 590. Unless your contractor can bend the laws of physics to his own purposes a dozer just can't pack. I'd say the comment by the NRCS agent speaks volumes on his level of expertise. (Not to say it hasn't worked for them in the past)

If you're not going to remove the top dirt from below the dam then you do need a trench, but I'm removing all of mine as it's too valuable to bury under a pile of clay, and I'll need it to dress the dam. And obviously you need a good clay core in the dam itself, unless the entire dam is built out of clayey material.

I understand what you mean by 'processing'. Mixing the heavy clay with the top dirt still gives a high enough percentage of clay in the overall mix to effect a seal, I'm just of the opinion that removing the topdirt down to clay and building from there gives a better seal.

Brettski- Don't make the same mistake I did. We removed ALL of the topsoil and used just clay for the dam. Clay by itself contracts way too much when in drought conditions. My pond didn't get a chance to fill before a drought hit us and the dam cracked completely thru. My NRCS agent to me we should have mixed some topsoil with the clay to allow the dam to expand and contract more without the major cracking. I have spent 2 years trying to seal the cracks. Have made great progress, as only have one small seep now.

Uh-oh...h20 kicks in with:

From a level of book smarts, this makes sense. From a level of street smarts, ask the man who owns one. Thanx for adding your (unfortunate) experience. This certainly adds credance to the practice of "processing" soil during dam construction. Is it possible that my soil conditions parallel yours to the extent that my guy's practice of processing is reasonable and even wise? When all the smoke blows away, it is difficult to argue with the success this guy has had in this region. I am still un-convinced and question his method of compaction. h20, what about this construction technique on your project...?

Seamless strokes are a good idea, to make sure the entire core trench is bound with good soils, end to end.
Compaction is very important. Water always seeks the path of least resistance, always. While there is always some degree of settling in a dam, the core trench needs to be compacted. His scraper is heavy enough to do it end to end, rather than side to side.

B-ski's question:
Bob's response:
OK, I get it on the weight of the scraper. I believe I may have painted a fuzzy pic on my question, quoted above. Both the scraper (e-mover) and the dozer transmit weight at both edges of the equipment. There is no compaction at all at the center of the equip. My question/proposal was to cut the core 1.5 times the equipment width to allow it to make multiple, parallel passes thru the core trench, adjusting the path to hit ALL areas within the trench. Lastly, are we nix'ing the dozer for suitable compaction regardless of the number of passes...period?

There are several things you can do on the core trench depending on how deep it is. I would say if are from 1 to 4 feet deep on it the best method is to cut the core sides to a 1.5 or 2/1 slope. This gives alot better seal on all sides versus just the bottom. Over 4 feet deep it is alot easier to bench back into the sides as you apply each lift. I would just be sure that the core trench is included in the overall bid. There is alot of times around here that the core is additional because of the unknowns and it is twice moved dirt.

As far as compaction there is a 20% volume of earth differnce between a dozer vs a scraper, according to the nrcs. So if I have a pond to build for the nrcs and I go in and tell them I will be using a scrpaer they will reduce the total yardage by 20%. We recently just built a 3800 yard pond with dozers only and they put in a 7/10's of a foot settling allowance in the deepest part of the fill, as you move out towards the end of the dam the allowance decreases. My opinion is yes a dozer is suitable for compaction if the lifts are put in 6 to 8 inch lifts. Is using a scraper or sheepsfoot better than just a dozer, yes.

Obviously you shouldn't build a dam out of pure clay. That's why pure clay cores are inside the dam, to keep the core moist, and if your dam soil has a high clay content the dam needs to be dressed with top dirt to keep it from drying out. Think about what is going on underneath the dam if you don't remove the top dirt from the base. The water permeates the base of the dam until it reaches the core, that means the front half of the dam is 'floating' on water soaked soil. If that isn't the case then you don't need a core in the first place. h2o did the right thing in removing the top dirt, but the wrong thing in using pure clay for the dam. Not only should the dam be dressed with top dirt but also the sides of the basin down to at least the lowest water mark anticipated in future droughts. Otherwise you will develop leaks as the clay in the banks dries out and have a pond that slowly receeds over the years. Brettski, just do the math on the dozer. My D5 weighs about 26,000 lbs but has about 3200 square inches of 'foot'. It's not a matter of opinion, it's a matter of fact. It won't exert any more pressure than me walking on the dirt. Dozers make quite a fuss and mess driving over raw dirt with the grouser bars stirring things up but they are intended not to pack by design. If you packed that trench with a dozer and then built a brick wall on it it would crack all to pieces. I'll quit beating this horse.

When h2O noted use of clay only for the dam, I kinda assumed that he meant the core. Now, reading back, it certainly appears that he means the entire dam structure. Yikes...major fundamental boo-boo. If this is the case, sorry h2O...didn't mean to rub it in.
My dam plans will, indeed, follow standard procedure of core construction and dressed with the saved t-s.

TN Hillbilly,
Please don't ever stop beating that horse!

We did dress the dam with top soil, but a few inches of topsoil is not enough to prevent the clay from drying out too much.

h2Ofwlkillr response:
I ain't cuttin' ya loose on this one. Please expand a little and paint a clearer pic of your experience. Are we talking a 5000 cu yd dam made of a solid mass of good clay, then dressed with about 6" of topsoil? Can you describe the equipment and construction methods that got you there? You are presenting a very interesting and helpful case study here and your experience may/will help me and others to learn. Thx.

Brettski,

I believe it has been mentioned a time or two on this thread, and that is the importance of cutting 1:1 minimum side slopes on your core trench. It is impossible to compact soil onto vertical side slopes as per your core trench photo. Also mentioned was the fact that you can then compact the center of the trench if it is sloped back. This is a very important point and I don’t know how you can do this adequately with vertical slopes. It is difficult to adequately compact a trench that is cut the same width as your equipment, unless you use a sheepsfoot.

Also, on the subject of a non-continuous core trench construction. A continuous, monolithic compacted fill is preferred. However, I have seen core trenches completed in sections as you describe. A couple of my ponds come to mind. Why……basically it was the easiest way to get around a perennial stream flow of about 200 gpm. We cut and then compacted fill with a scraper on part of the core trench on one side of the drainage. This gave us a place to route the perennial stream as we cut and compacted fill on the remaining core trench. We essentially flip flopped the stream from one side of the drainage to the other. Worked great! I will mention however that both dams leak a little (about 2 gpm each). Most dams will leak or seep just a little but it is nothing to be concerned about unless the leak is muddy, and then you are losing fill dirt and the dam integrity may be compromised.


I guess the reason core trenches get so much attention on this site is because of their importance to the stability of your structure. Very difficult problem to remedy after the dam is completed and full of water.

Ed

Brettski...grab some coffee and a snack, this is a long one.

Actually the dam was closer to 8000 cu yds. Core trench is 16-18' wide and only about 24" deep, as the topsoil is very thin. The pond was dug to about 12', with no signs of any porous material, just very good yellow clay. The dam was compacted by a D7 dozer in 4" layers. When construction started, the clay was quite moist. We had to wait to start building because of excessive rainfall and very muddy conditions. After we got started, we went into a 5 month stretch of less than 2" of rain. This is where the problems started. Most of the dam has 6-8" of topsoil on it ( some a little more..some a little less ) The topsoil was used to level and smooth everything out and to give the grass something to grow on. About a month after construction, the cracks started to appear. Nothing too bad at first, but after 5 months of drought it got real bad. The cracks,3 of them, ran 6-7' deep, from inside the basin to the backside of the dam, and were about a foot wide at the top. I probably could have minimized the effects of the drought, if I wouldn't have been such a tight -ss and spent the money to water down the dam. But I didn't and so I've learned the hard way not only what I did wrong, but also how to repair some leaks. My NRCS agent and my excavator both thought the cracks would close and seal on their own, IF I got a few nice soaking rains before the pond filled. That didn't happen. The drought was broken by a 4" rain that fell in 3 hours. The pond filled to 3/4 full overnight. The clay didn't get a chance to swell before the water started running thru the cracks. My dam must be well constructed, because it didn't fail, nor did it wash big holes out of the cracks. The cracks didn't seal themselves.(can you believe it?) So, my quest to seal the cracks started. Crack #1 was the worst crack and really the easiest to repair. I spent a couple of mornings with a long rod and buckets of clay hand filling and packing the crack. it has never leaked again. Crack #2 didn't work that way. It still leaked afterwards. Meadowlark actually gave me the idea of how to fix this one....from the backside. It is now repaired. Crack #3 neither worked completely. It still seeps. Not alot , just enough to keep the ground moist. At this time I'm not too concerned about it. I plan to extend the dam in a year or two and the area of the leak is where the new section of dam will tie in. I will fix it then.
I hope this answered all your ?'s.

Ed,
Good to hear your input...thank you. Meadowlark would sing harmony to your statement regarding segmented dam construction. His posture was more geared toward allowing an opening thru the dam during construction to allow the release of any water build-up (expected or unexpected). Then, carefully pack the trench with good clay soil when pond excavation is done. Pretty much the same process, m/l. We are going to install a drain so this won't be necessary. For this reason, I continue to lean toward cutting and packing the core as one monolithic unit...why not? I also agree with the wisdom of sloped walls; that one comes right out of the books.

h2O....Nice monologue; it means alot to me.
You musta been sick...and scared! You noted in your previous post the hindsight of processing the soil by adding t-s to temper the clay. At the risk of redundency, I want to make sure that you meant the entire core mass....? Based on YOUR experience, would this have been wise for your project? It certainly synch's with Bob Lusk's post c/o Otto's expertise.

Yes, I would have and have done with 2 ponds built since. I have very heavy rich in clay soil. My topsoil alone probably has enough clay content to safely use in dam construction...minus the sod of course. My last 2 ponds we just scraped the sod off and didn't bother with the topsoil. It was mixed with the clay and used in the entire dam construction...core and all.

h2O reflects:
My dirt-guy would shake your hand and buy you a beer for that one. Did you core the dam on these last 2 ponds (embankement ponds, I presume?) and did you use similar build/compact procedure with the D-7?

Yes, they were both embankment ponds. We used a D4 on both of them. Same compaction method. Both holding water well.

The boss and I just took a trip to the project to shoot some elevations into one of the draws to prep for excavation, throw out some grass seed along the new driveway, and roll a few truck and tractor tires to the top of a knoll overlooking the basin area. All fun stuff...even the tires :rolleyes:
As I stand and look out and dream in my mind's eye, I am still thinking alot about this dam construction thing. It dawns on me that earlier in my short-lived PB existence, ML sparred with me on dam construction. Any thoughts, ML?

Brettski,

First thanks for pointing out this thread...it is one of many I missed completely during my hiatus from the Forum....which you ended with your breadcrumbs.

I had to smile great big at H20's reference to the back-side filling of cracks and stopping leaks which I wrote about many months (years?) ago. I'll never forget a whole bunch of experts on here saying that technique would never work...and my skoal chewing East Texas operator laughing so hard when I read him some posts that he couldn't stand-up. The skoal man was right on...he said get on that da*n dozer, push up clay on the backside, pack it as you go, make it a minimum of two feet thick and it will never leak again. He was absolutely right and asked me to post it here and see what folks would say.

Were all those outside experts wrong who said it wouldn't work? No, I would not say that at all. Rather, I would say that my skoal buddy knows the soils in this area better than anyone not in this area...hence he knew from years and years of experience that the back-side packing technique with my small dozer would work in my particular soils...and it worked perfectly, saving me hundreds(perhaps thousands) of $ and very likely the entire dam and pond. That pond now is one super F1 bass pond.

So why am I rambling about a technique in which you have no interest and certainly hope to never use in your project? The moral of the long story is that a really good local dirt guy knows your dirt better than anyone outside your area, anyone.

I wouldn't do things exactly the way your contractor has, but pretty close...the thing I respect is that you have checked him out, seen his work (I presume), talked to his past customers and know that he is a good contractor who has worked extensively in your soils. You have also made yourself a "smart buyer" and are now qualified to question his technique. Trust his judgement until he proves to be untrustworthy.

I respect the inputs you have received on this thread...but if I had been afraid to use a dozer to pack my clay, I never would have built the three ponds I've built with three more on the way....not a single one was built with anything but a small dozer which was assisted by a track-hoe, a loader and dump trucks when the serious dirt moving was going on.

Get the very best local dirt man you can get, check his work, talk to his customers and if everything checks out, trust him to do the job until he proves to be untrustworthy...and always, always be a smart buyer.

You probably wanted me to give you a much more technical input....but my input to you, at this point in your project, is to enjoy the journey. You did your homework and if you hired the best man for the job, let him do it under your watchful eye.

Interesting post. It reminds me of all of the times I didn't bother doing something because I knew it wouldn't work.

I'm reminded of Mike Otto's story about a dam he wasn't going to build because there wasn't enough moisture in the soil to pack the clay. A local dirt expert of some kind told him that if they waited for moisture in that area, they would never build a dam. He said to go ahead and build it. It would work. Mike built it and it did work.

Thanks, ML; good story, helpful input...the wise stuff from you that I hope for and appreciate.

*** UPDATE ***
I had another great phone conversation with my contractor the other night. One thing for sure, when I want to talk, he calls me back within 24 hours and spends all the time I need (sometimes I need alot ) Anyway, after we discussed a buncha plans for this year's attack, I told him that I wanted to address his plans for the dam construction once more. I hit him with all my concerns...we have jousted like this before and he is receptive. He assured me that his plan to finish both ends of the core will ultimately wind up being similar to running the entire core at once. As TN HB said, in order to get down into the sides, you gotta ramp in, ultimately cutting back into the center area to do so. We discussed his rolling back the TS with the clay he dug out. Response; suitable method of processing excellent clay subsoil. I asked why he even cut that little section of the core. Response; the bottom/center portion is going to be left as complete, but it allowed him to glimpse at a wide swath of what is down there. I told him I was concerned for use of the D6 to compact. We discussed the lack of compaction of a dozer; he said his D6 weighs 46K and thought he remembers the number "70 psi"...couldn't swear by it without looking. He quickly redirected me; they will use his E-mover to place and compact the core soil in thin layers. He noted that he thinks he is going to bring in a 2nd E-mover due to the amount of soil to move. Knowing full well that I was focused and intent on the dam, he said "I'll tell ya the same thing I have told all my pond clients. Providing there is good clay in this site, we are going to take all the very best material and it is all going to be packed into the core and the upstream side of the dam...period. If it's not here, you will have to bring it in. Best stuff up front...lesser soils go behind". He also added "now, make no mistake, there is going to be soil that gets pushed into place with the dozer on the dam...that's just the way it is during construction, but where is needs proper compaction on the dam, it will be thin layers and run over by the E-movers". I told him that I wanted to see a 1:1 on the edges of the core. He did not object and readily admitted that this is, indeed, standard practice. He said that he didn't normally make an effort to cut his cores back that much, but will be happy to do so for me.
My project will be a short but substantial dam mass. It will be 15 feet high, 20 ft wide roadbed, about 300 ft wide across a valley. The back side is .7 acres and the valley will be filled with pond waste soil. I figure the slope on the back side at about 12:1.
Lastly, my NRCS agent went out and GPS'd the perimeter of the proposed pond, my new driveway, and a couple of property corners. He was able to drop it onto an aerial photo for my latest motivation

That is going to be one nice pond. Now to help us out you need to take the map and add on the cleared areas and the possible future location of the small pond , the nature areas and what ever else we are missing so we can get the total effect. Then we might be able to add about 100 more things to think about.

.7 acre pond below the lake. Sounds good to me. Maybe you can add a pond above the lake, too.

I'll say!

Whether you're goofin or not, you gotta know that I'm gonna do exactly that...sans the .7 ac pond. The GPS points were taken following the remaining treeline after all the timber was extracted. The entire pondsite and behind the dam is bald, waiting for phase II. The .7 ac behind the dam is gonna be loaded with waste soil. But, never fear...I have been shooting elevations thru the balance of the timber and I have a .5 - .75 ac hole waiting in the main timber block, south-east. (ssshhh..the boss might be wistening...be vewy, vewy kwiet)

I was not "goofing" at all but was serious. I envision this ( all you have done) to be an excellent learning tool for many on how to plan and learn about starting a pond. A good place to send prospective pond builders to in a future frequently asked questions area. A trip through the process from a to z. So we need to gather your story (by link if that will work) in one place and plats/pics/plans will really help. How about that idea ?

I just wish I had been as thorough as you are. I think the results will speak for themself.

Thanks (again) for the many prop's, guys. This is one big deal for me. I have never undertaken anything this big before, and I'm only starting. It may send me to the poor-house, but I'll never look back and wonder if I didn't try hard enuff.
Eric, you are one "house icon" away from a complete chronology. If you are having trouble falling to sleep, my website should help. If nothing else, it will prove my manic commitment.
An interesting note (at least to me, it is); I prepared a couple of projected maps of the proposed pond based on the topo maps I took from the USGS Terraserver. When I put this new actual GPS map against them, they are very different....evidence of the potential "low detail and accuracy" of the on-line topos. I think the surface area is close, but the shape...fuggedaboutit.

I don't understand. Are you getting a 5.5 acre pond?

It looks awesome.

...God and my loan officer willing, datsdaplan. I will likely lose about .3 - .5 ac surface from a small building site bump-out peninsula and a shoreline road that will follow about 75% of the perimeter (tying into the the dam roadway).

That is great, Brettski. I had thought your were originally planning for just about an acre.

Great news!. Congrats.

The wound has been healed! Da core, she be done...and done right! Based on the edumacation from my valued PB associates, I was able to bend my contractor's standard procedure to meet my construction requirements. Quite simply, he removed the topsoil from the damsite area. Then he cut a continuous core from one end to the other. Per my request, he "laid open" the core trench to about 1:1. Then they used the dozer to select the clay soil from 2 areas directly adjacent to the damsite that contain killer clay. They laid is the clay with the dozer in thin layers while they compacted it with a loaded earthmover. They stopped at natural grade. Tomorrow, weather permitting, we are going to lay in the drain pipe, valve, and valve well. The day after, good chance the balance of the core (above grade)and the dam start taking shape.
I'm satisfied. Thanks to all for sparring with me on this one. It made a big diff.