Pond Boss Forums POND CONSTRUCTION Soil questions Need some advice about compacting

I picked up a soil survey last week and it shows the site for Cindy's 5 acre pond site as A1. If I understand correctly "A1" isn't good in this case. There are a lot of man made ponds in our area, but they are mostly in B1 zones. This agrees with what the pond builder told me. The samples down to about 3 feet in the site were very sandy so he's going to harvest clay from Cindy's cotton field (B1). The thing that concerns me is that he is only getting that clay for the dam core (keyed). 6Also he is relying on the dozers and a pull behind scraper for compaction. I'm not sure but the scraper might only be used to compact the core. I'm a little concerned that the sides and bottom might need more compaction in these drought conditions.

Now this contractor is well liked and respected in the community. His father built ponds for a living and that's what this man has done all of his life. He seems honest so far.

I'm wondering if the techniques and standards around here are influenced by the fact that the normal rainfall is about 55 inches/year. In a normal weather pattern the 2 draws that feed this pond would flow constantly and there would be many little "springs" in the site.

If he relies on the dozers for compaction I'm thinking about renting a compactor myself and doing it after he finishes. I can rent one of these for about $1000 for a 2 1/2 day weekend.

1 Could those "many little springs" turn into many little leaks?

2 Is that the right type of compactor?

3 Is that size overkill for 5 acres?

4 Is a weekend enough time?

5 Is that money well spent?

6 Am I asking too many questions?

my attmepts at yer questions are not in order, but here's my thoughts:

we've used those to backfill tank excavations and the compaction is good enough to stabilize fill near building foundations and where traffic will be. i've only seen it used on road base materials not clay. also, i've only seen it used on flat, i dont know how it would be on slopes. on clay to seal water, i dont know if they'd achieve a better compaction than a big sheepsfoot....somebody here should know that.

the surface area and psi of a big sheepsfoot i would think is much higher. there could be a bang for the buck issue there with the drum roller, it might be better than nothing, but not as good as having yer contractor use a sheepsfoot. the moisture of the clay will be very important too.....not too wet, and not to dry, but moist.....that's how you want the clay for best compaction.

at the same time i know of successful jobs filling in small lifts (<1 foot) and just using the dozer, the key is small lifts.

the vibro drum roller is cool, very fast, but you'd have yer hands full to cover 5 acres in two days....if you get it make sure it has lights and be prepared to stay up late.

Thanks DIED. The reason I asked about that type of compactor is because of this webpage I found. There is a comparison of different types of compactors halfway down the page. A vibrating roller/plate is the type they recommend for sandy soil. From the few soil samples that's what it looks like we have.

To roll the slopes I was picturing going straight up and back, from the center of the pond to the bank, instead of doing laps and leaning to the side. What little experience I have using a roller was on flat land though.

GW/DY

Is this the only possible site on the land? Sandy sides make me nervous. It only takes one small mistake or oversight to create an on going problem.

DD1, we're building another 1/2 - 3/4 acre pond in an area with good clay content.

I guess I need to do more soil sampling in the 5 acre site. I'm starting to think that maybe there is a layer of sandy soil covering soils with more clay. The draws stopped flowing several months ago because of drought, but a few weeks ago there was still a puddle of standing water in a hole that looked over 12" deep. I'm going to have a look today and see if it's still wet.

The creek that the two draws flow into might give more clues. It's in the same zone in the survey. The surface soils around the creek drain extremely fast. The creek itself has cut vertical banks of about 4 feet. This creek has only stopped twice in 50 years, now and last summer. BUT, even after stopping for several dry months it has never dried up completely. It is always at least a series of puddles. I'd even say it maintains more water area than dry. So, the creek bed must be sitting on something fairly watertight, yes?

Maybe the pond builder is counting on finding clay deeper, in the middle of the site, and pushing it up the banks to seal them. Does that make sense?

Thanks.

I'm not a Pro pond builder so keep that in mind. I just have problems with the idea of trying to seal the sandy sides of a water hole. 5 acres gives a lot of room for mistakes and sand is the stuff of aquifers. Maybe the dozer driver knows the area and figures he can do it.

I've had several small stock tanks cleaned out on my land. On 3 of them they have hit sand. I have yet to be able to seal the bottoms with either bentonite or clay. Others have been more successful but I figure I am in real trouble when I hit either a sand or rock strata.

This looks like it might be a good description of what we have on this property in general. Our place is right in the middle of the band of Tifton soil. It seems to fit with my hope that the sand is covering decent pond building material.

From the above link: "A typical Tifton soil profile consists of an 11 inch topsoil of dark grayish brown loamy sand. The subsoil extends to about 65 inches, strong brown fine sandy loam to 22 inches; yellowish brown sandy clay loam to 40 inches; yellowish brown mottled, sandy clay loam to 60 inches, and strong brown, mottled sandy clay to 65 inches. Two distinctive features of the Tifton soil profile are the presence of more than 5 percent ironstone nodules in the upper part of the soil and more than 5 percent plinthite in the lower part of the soil."

This is (was) the creek which the pond site drains into. It's not considered seasonal. My 84 year old neighbor says it only stopped flowing once in the previous 50 years. Last year when it first stopped it stayed mostly wet. Today I saw it for the first time in about 3 weeks and it's almost totally dried up. The pond site is about 400 - 500 feet away from the creek.

(click on thumbnails)

Almost the entire creek bed and surrounding soils are like "all purpose" sand.



But... in one of the few wet holes I found this large lump of nearly pure clay sitting on the bottom. You can where I scraped my fingers across it to grab a piece.



I found more clay downstream. This clay had some sand mixed in but was still extremely plastic. I only found these few small spots of clay near the few remaining pools, but I'm hoping that there's a lot more of it below the sand. I'm assuming there is because something has to be holding that water...



Here is the soil that was dug with a post hole digger down to about 3 feet. This is from one end of the dam.



The draws for the pond are dry except for this one hole just upstream of the proposed dam. After 3 months of almost no rain this pool is still almost 2 feet deep and about 5 X 15 feet of area. The soils around this draw are very similar to the creek and the sample above.



I guess the big question is do we clear the trees. It would be a shame to have to stop after that.

Aside:

1. GW, could you please include a "how to" on thumbnails for a future signature tip?

2. Save those tips for reference - some of them (at least) are archive material.

edit: I don't think I can manage to describe the photobucket thumbnail process in my signature because of the character limit. (the signature's not mine)

I'll post it here and you can copy it if you like. Maybe someone could test my instructions cause my brane is tie rod.


1 Open your photobucket account which will display your image collection as thumbnails (clickable small versions).

2 Just under the lower left corner of each (photobucket) thumbnail is a small (empty) check box followed by the image file name. Check this box by the image you want to post by left clicking it.

3 Scroll to the bottom of the same photobucket page and you will see a box with the phrase "Generate HTML and IMG code" Click that.

4 That will take you to a page with 5 boxes of various code options. The 3rd one is titled "IMG clickable thumbnails for message boards".

5 Photobucket makes it easy to copy the thumbnail code. You just move your cursor to the line of code in that box and left click it once. That code is now "stored" (copied) in your mouse pointer. Alternatively you can highlight the text, right click and select COPY.

6 Return to PB and type your post as usual until you come to the part where you want to insert the thumbnail. (I usually add a blank line or two before adding the image)

7 Make sure the cursor is below the text you've already entered and paste the copied code into your post. You can do that by right clicking and selecting PASTE, or you can simply hold down the CONTROL button on your keyboard while typing a "v".

8 If you want to add more text after the thumbnail, hit ENTER once or twice to give yourself some room, and then continue typing.

9 If you want to check the post, select the option "Preview Post" below the reply window. This will open a new window with a working preview including a clickable thumbnail of your image. Click the thumbnail and it should open another window with the full sized image. Close the preview windows and send your post.

You can do the same thing for multiple images at the same time. Just click more than one image while doing step 2.

Just for the heck of it I'm posting a video of the creek from a few years ago after a 2 inch rain.



I went back the next morning to shoot some more flood video and got a surprise.

GW - I am an Engineer and a Geologists and do soils Engineers for a living. In addition, I build ponds on the weekends so I have a little practical experince.

1. As far as compaction goes, sheetsfoot rollers are what are used to proper compact clay.
Typically vibratory rollers are used on granular soils. When you design a dam you usually would like to get the clay core compacted to 90% of maximum dry density. You can get this from a standard dozer tread but it is easier to get it with a sheepsfoot. Just as important is the moisture content of the clay, typically you want it on the wet side of optimum so if there is a little settlement it will be selfsealing.

I just finished building a one acre pond this weekend and relied only on my dozer for compaction. In my area this works well so if your contractor has had good results, try it. I think proper moisture content is probably more important than % compaction.

Thanks jas.

What I'm hoping is that there will be enough clay to mix in with the very sandy soil. I thought I had Tifton soil, but using a better survey I see that both the creek and the pond site are in a mixture of Osier and Bibb soils. To my uneducated brain neither look like good pond building material. On the other hand something is holding water pretty well in places in the creek and pond site. At least the Bibb soils have a moderate permeability. I would guess the the creek is Osier since it drains extremely quickly. I did find those few pieces of pure clay, so I'd like to believe the contractor is right to assume he can build a leak-free pond. He doesn't guarantee it though.

I dug down about 2 feet in the deepest part of the pond site. This was about 2 or 3 weeks ago and the ground was very dry. It was also very hard. I couldn't drive my shovel more than a couple of inches into the soil and then I'd use leverage to break it up. The soil looked the same and had the same properties top to bottom.

Here's the hole. The sides were very stable.



As I broke it up it tended to stay in large pieces.



Here I mixed some water in. I could feel a large amount of sand in it, but it easily held it's shape.



Here's the "sling it and wing it" test. The ball on the right was the drier of the two. I chucked it pretty hard and it hit a flexible part of my truck with 1/2 of the soil flying off on contact. The sample on the left got a little more water added and I hit a more solid area of the truck. All of it stayed in place. I have little doubt that it would stay there until it dries.

Does any of this sophisticated research give anyone a better idea of what I'm working with here? The bottom line is that if the clay content of the site isn't good enough there is a good source only about 300 feet away, where the dam core is being collected.

More scientific data:

I should clarify something. I know that nobody can really advise me about our soils and their ability to hold water. This is Cindy's pond and I've informed her of the situation to the best of my ability. Her (and my) confidence in the contractor's ability is fairly high. I know that can lead to trouble, but he is a local and is very well liked by all of the people we've come to respect around here. His reputation is golden. He grew up building ponds in this county with his father who is also a very well respected member of the community.

Even if we discover that the soil isn't good enough after removing the trees, we still have a good supply of clay very close by.

I'm sure the pond can be built to hold water, I guess the question is whether or not we will have to do more labor to move extra clay. Anyone care to make a prediction?

Does anyone think I have a decent chance at winning an Oscar for my documentary above?

GW,

It’s all about risks and reducing risks to an acceptable level within financial constraints.

My opinion is that the methods of and needs for compacting are very much dependent on local conditions...in some areas of the Country a dozer is sufficient for compaction and in other areas, it may not be sufficient. Here in East Texas, thousands of ponds have been built successfully with nothing but small dozers including three I have built/renovated. In Missouri, my Dad built a pond that didn’t leak using an old John Deere tractor to pull a hand operated sled (not advisable when you are the kid “operator” on the sled).

Unless you are an expert in soils and pond construction, your best bet for reducing risks is to find the very best, knowledgeable, experienced contractor that lives in the local area and raises his family there. Ideally, his business, reputation, and livelihood depend on building ponds right. When you find that person and independently verify that they know their stuff, then the best thing you can do is trust them to do the job right…and let them do it. Things can still go wrong, but if you have that trusted partner, you have reduced the risks about as much as one can reasonably do. The next best thing, in terms of risk reduction, is to do the work yourself, but under the close guidance of a local person who has the necessary knowledge and skills described above. In the absence of either of these options, risks may be high and disappointments severe and expensive.

Thanks Meadowlark, that was perfect.

GW, I must have missed this thread and wondered how everything worked out with Cindy's pond? If you have covered this somewhere else, please aim me in that direction.
PS - love the thoroughness of all of your posts.

GW I missed this also. The dirt looked ok to me including that stuck to the truck side.

Thanks guys.

rmedgar, we only finished getting the sites cleared about a month ago and now we're waiting for the pond builder. The loggers worked by hand and took something like 6 or 8 weeks to clear the timber. They were very thoughtful and did a great job. Our pond man has a very small company and he always has 4 or 5 jobs stacked up. When he finishes his current job he'll start on ours.

Here's a few threads about the ponds:

http://www.pondboss.com/forums/ubbthread...=true#Post99168

http://www.pondboss.com/forums/ubbthread...=true#Post91855

http://www.pondboss.com/forums/ubbthread...=true#Post91916