Pond Boss Forums POND CONSTRUCTION Soil questions First Time pond guy here Gravel question :(

Ok ...I hope you all don’t kill my dreams but I always wanted a Pond ever since I was a boy. Now we finally moved out into the country and bough 2 and 1/2 aches and a pond guy did some test holes. 2 of them and both had great clay about 9 feet down then gravel. He dug about 12 feet total and had gravel in both spots. Ok he said he could do the pond but it would only be 10 feet deep with Bennite or something like that and the cost was 22,000 dollars. I have my masters in Biology so I know about Eutrophication and know in a shallow pond you get that and I don’t want that. Another guy who did a few ponds said no problem and he would pack clay and all would be fine. 10,000 without Benite and 14000 with. Both ponds would be about 1/2 archer??? Something like that. The second guy said he could make it 12 feet. Help...I am way out of my element. I really would like a pond and if this does not work the money goes into one of those swimming pools...LOL YUCK!!! I really hope you all have good news for me..It took me about 2 days to find this site and I am really excited to hear what you all say...thanks!!!

Welcome to the forum!

It doesn't matter how deep they go into the gravel providing the clay is good, AND they pack it back into the pond bottom, knitting it together with the clay at 8'-9' depth. Minimum of three 6" lifts, knitted together. I'd really prefer to see 4 lifts, so you'd have a 24" layer of properly compacted clay over the gravel and make sure that it's tied into the shallower existing clay. Think of making a bowl of clay that you want to hold water.

Usually tracked equipment (dozers/excavators) don't have enough psi ground pressure to knit the layers together. Multi- tired pan scrapers full of dirt or sheepsfoot rollers. If a flat roller is used, think of them making layers of paper. Water can leak between the layers. Knitting the layers together prevents that. One thick layer won't work either, because that thick of a layer of dirt can't be properly compressed.

I would be very hesitant to count on bentonite to keep a gravel bottom from leaking. I do not recall anybody on this forum posting positive results about it fixing or even slowing down leaks. I would much prefer a 9 ft deep hole with good clay, well packed, on the bottom and aeration to keep the water viable and the fish healthy.

Dave,

I have used Bentonite successfully to stop the leaks in my pond. But I had a sand seam I used it to seal and to enhance the clay that I have on site. But like you and Scott have mentioned that a good compact 4 6" lifts would be the way to cover the clay and not mix the bentonite with the gravel. If it was me and to do this only once I would test the clay with the bucket test and if needed I would add bentonite.

But with all that clay on site and having to be removed to make the hole you should have plenty to cover the bottom 24" thick just don't skip the compaction and separate lifts.

If you do use bentonite keep it away from the first couple of feet at the edge of the pond. The reason for this is if the water level is low and the bentonite is expose and when it does get wet it is very slippery.

Why can't you live with ~8 feet deep pond in clay without any additional expenses? You mentioned eutrophication but you won't avoid it in deeper pond either (sure, it will happen slower). By the way, 8 feet is quite suitable depth.
Clay ponds do not get overgrown with various underwater plants as fast as peat ponds (just an example).

Depending where in Ohio, with the winter we are having, I'm not 100% sure that an 8' deep pond would survive, especially if a winter like this one followed a dry summer/fall and the water level dropped. In any case, since you ran into the gravel, I wouldn't take the chance of stopping shy of the gravel and hoping that there is enough of a clay layer to seal the pond. If the pond leaks at the bottom, it will cost you pretty close to the same amount of $$ to fix the leak.

If the clay is good (like lassig said, do the bucket test) then you shouldn't need bentonite.

Welcome to the forum thor!!!

Since you KNOW there is gravel below the clay, I would stay away from the dirt guy that suggested only an 8' depth...(makes me think he will just dig a hole, not compact, and call it done).

If there is enough GOOD clay, you will want the hole dug well below the final proposed depth and as esshup said, back-filled and well compacted to a minimum 2 foot thick clay blanket under the ENTIRE pool area...side and all. Spend your money wisely, bentonite has to be properly mixed with soils and also well compacted to be effective.

What they said...
I would shoot for at least 12 feet deep, especially given the cold winter we have just had. Also when we are dealing with what is looking to be a stupid-hot summer, your fish may need some refuge in deeper and cooler water to make it through the seasons.

Don't forget to look at the literature available on this site. Many of us here build a pond first, and then found this site, so you are way ahead of us in getting the perfect pond. Get "Perfect Pond, Want One?"

Curious if you hit ground water in that gravel or not? Having to pump while excavating around this area is common when inflow from groundwater is too high.

Thank you so much guys. You gave me some great ideas. There are some mixed views about the depth. I do live in Ohio just south of Lima. If 8 foot is all I need it would be fine. I am going to get some of the best Aerators which brings me to my next topic. If I do have an 8 foot pond wouldnt an aerator save on the ice build up ..?? what are your sugestions ??

Yes, the aerator would help a lot. But, if it was my pond, I'd go deeper than 8'. Once a pond is dug, it starts to fill in. Many different reasons, but that's just the nature of the beast.

If you only go 8', and lose 3' of water because it was a dry year, you are going into winter with only 5' of water which is very iffy.

Go and talk to the guys at the local NRCS office.

As Scott said it does reduce ice build up. but not that much. Case in point my pond this winter in west central IL. I run an aerator 24/7 if the air temp is below 35 degrees (so just about 24/7 this winter). At times (like yesterday morning) the hole the aerator was keeping open was only 6' across. Normally it is 30 or 40 feet across (it was like that on Saturday). My pond was 3 to 4 feet low going into winter after battling the drought of 2012 and the slight drought on June '13 till now (still in a drought area). The runoff from the snow melt almost 2 weeks ago (see post On Lassig Pond) almost filled the pond raising it 3' in the matter of hours. Point here is this exposed the ice that had form in the pond and it was 16 to 20 inches thick not just far away from the aerator but within 10' of the typical open hole.

So if your pond is only 8' deep and you enter winter low because of drought and then get 1 to 2 feet of ice your fish don't have much water to live in. Also you don't have a deep water hole for them to go to that has warmer water. My pond being 3 to 4 foot low still had 9' average depth and a deep hole that is 12' deep.

Since it looks like you have to go into the gravel level to get any reasonable depth why not go deeper? Go an average 9/10' deep with a 13' to 15' deep hole? I would only do this if there is enough clay on site (or close by) to seal the pond correctly (24" blanket in 4 6" lifts compacted correctly).

Final note realize that winter aeration is done in shallow water to not disturb the deep warm water. Also should be done close enough to shore so that the water stays open to the shoreline encase something or someone falls in, getting out is easier. Summer aeration is done in deep water to turn over the complete water column of the pond.

Thor, give Ted Lea at Forever Green a call. He lives close to you in Waynsefield and can help you with all your needs for your future pond!

Thor - 1, You have a unique situation and be very very careful hiring a contractor. You should do lots of in-depth homework (maybe 2 yrs worth) before choosing a pond builder. 'You dig a hole, but you build a pond'. You want a contractor with lots of experience building ponds in marginal soils and not just good clay soil. It can cost twice as much to fix a leaky pond as it cost to first build the pond. Check several of his references and visit the ponds he built that had problematic soils - very important. All pond owners love to brag about their pond. Visit the references - very important.

2. The next important factor is a getting a good written contract. Building a pond in marginal soils is very risky so a good legal binding contract is very important. Some contractors may not agree to a contract due to the poor soils. Make sure how a leak versus normal pond evaporation is quantitatively defined in the contract. Ther is a good chance you could end up in court when building a pond in marginal soils. Read the good article in the back issue Jul-Aug 2013 Pond Boss magazine article:
HAND SHAKE OR CONTRACT? SPELL IT OUT. Tim Matson and Lusk describe what is needed for written agreements with pond contractors. Discuss sketches, engineering, staking outline, dam features, and cost estimates to avoid a hole without water. Include details, materials, deadlines, labiality insurance, cost figures, plus some added legal points from a lawyer.
http://www.pondboss.com/back_issues.asp

3. Pond construction techniques will have to be done by a contractor with very good experience working with marginal soils and proper techniques for soil compaction. 1. For best compaction clay should have the proper moisture even if the contractor needs to use a 'water wagon' to moisten soil for best compaction possible. 2. previous suggestions were good for compaction. I add this. Since the clay needs best compaction possible accept nothing less than a double barrel sheepsfoot roller and as esshup said nothing more than 6" lifts and better yet 4". lifts since you need an extra tight 2ft thick liner. If I was you I would demand a vibratory sheepsfoot roller for best compaction possible. In good conditions a weighted pan scraper full of dirt will not knit layers together and is more likely to just compress the layers into flat sheets and not inter-knit the lifts together. Expect all this extra effort to cost a little extra money, but it will be worth it instead of dealing with the aggravation, legal feed and repairs of a leaky pond. Many members here have shared their woes and trials of a leaky pond.
http://www.cat.com/en_US/products/new/equipment/compactors/vibratory-soil-compactors.html
I sent 'esshup' a pic and he may provide below a picture of what clay looks like when compacted and inter-knit by a vibratory sheepsfoot compactor. That picture is from a educational pond project that the best pond builder in our county said a pond could not be built in the current pond site that would hold water. The vibratory sheepsfoot was the main "secret" for the project.


4. As a minimum, the hole will have to be excavated and then the bottom and sides layered with a minimum of 2 ft of clay. However, here is what I suggest for the best side wall liner. Over excavate the final size by 8'(bulldozer blade width). Then compact clay in layers in that 8ft wide band around the outside so the side walls are 8ft thick. Compact at least 2ft to 4 ft of clay on the bottom and preferably the bottom 2ft has bentonite mixed in with the bottom layer and well compacted in 4" lifts. The pond bottom is usually quite small compared to the surface area thus overall cost of bentonite is less than for an entire pond basin. Be aware you might not have enough clay to build the pond correctly.

5. You might want to consider this. Build a 1/4ac deeper pond and a smaller, shallow minnow (forage fish) pond about 0.1ac & 4-6ft deep to get the extra clay needed for the bigger deeper pond. Many here would love to have that 2nd smaller minnow raising pond. Then use the minnow pond to supplement forage for the big pond or cash rent the pond to a fish farm (Shelby Fish Farm local to you) to grow minnows-fingerlings.

6. A 1/4 acre sealed pond is much better than a 1/2 ac leaky pond.

Bill,

As always excellent advise and thinking out of the box. Wish I would of had this help before I damn the ravine. Taking notes hopefully for the next time.

Here's a picture from Bill Cody on what clay looks like after compaction with a vibratory or tamping-foot sheepsfoot roller.

Thor, here is a little primer on compaction and the different compaction equipment.

The following is from http://www.gradingandexcavation.com/GX/Articles/How_to_Select_a_Soil_Roller_8467.aspx

Contractors use a number of different types of soil and aggregate compactors these days. Common types include: sheepsfoot rollers, which run static and are typically towed; pneumatic-tired rollers, which use rubber tires to provide the familiar kneading action of soil or subgrade; vibratory rollers (smooth drum), typically used for granular and mixed soil materials; and tamping foot, which combines the advantages of a vibratory roller with a sheepsfoot.The sheepsfoot roller is most effective for compaction of plastic soils like clay or silt, according to Bomag Americas, a leading roller manufacturer. The sheepsfoot compacts from the bottom of each lift towards the top. High contact pressures cause the feet to penetrate through the loose material and actually compact the material directly with the foot tip.

A number of passes are required with a sheepsfoot roller because of the small area compacted by each foot. Self-propelled embankment compactors, such as the Bomag BC462EB and the BC772EB, are capable of higher productivity than towed sheepsfoot rollers because they can travel at higher speeds. And while the teeth differ slightly in design from a sheepsfoot, the Bomag embankment compactors achieve compaction the same way.

Pneumatic-tired rollers generally compact from the top of the lift downward. The relationship between the tire contact area and the ground contact pressure causes a kneading action, which helps seek out soft spots that may exist. Light- to medium-weight self-propelled units are used primarily for compaction of granular base as well as hot mix asphalt.
Vibratory rollers work on the principle of particle rearrangement resulting from dynamic forces generated by the vibrating drum hitting the ground. As particles in the soil rearrange themselves, voids between particles become smaller, causing an increase in material density. The best vibratory application is the compaction of granular and mixed soils.
A tamping foot roller has feet, or pads, that penetrate the soil, compacting from the bottom to the top for uniform density. The forces of gravity and vibratory impact simultaneously compact from the top down. Due to the foot shape, and in combination with vibration, these rollers achieve a kneading and impact effect while the imprints left contribute to a reduction of water content.
It is often recommended, says Bomag, that a vibratory smooth-drum roller be used on materials having up to 10% cohesive content. A tamping foot, or padfoot roller can compact soils having as much as 50% cohesive content.

Large Versus Small ProjectsCompactors required by a contractor will depend on the size of the job, the type of material, lift thickness and job-site congestion. On a smaller project, material is generally spread and compacted until density is achieved, followed by another lift of material until the process is completed. In such a situation, compactor maneuverability is more important than size, as hauling and spreading equipment may be sitting idle on the job site during the compaction process.

On a larger project, such as a highway, dam, levee, or runway, the compaction process may be continuous. In this case, Bomag says it is imperative that the compactor’s size and productivity complement the hauling and spreading equipment on the project. Maneuverability is less of a factor as compactors frequently shuttle back and forth in order to reduce turnaround time. Thicker lifts or rock fill will require the largest rollers available in order to maintain project timelines.

Caterpillar recommends selecting a machine that matches the production of your earthmoving fleet—weight is the key. The machine must be able to keep up with the pace of the project. Caterpillar has charts that show general productivity of its rollers.

The size of your compaction equipment depends on the factors above. For example, if you need to compact thick lifts of limestone rock for a mile-long levee in Florida, you will want the largest smooth-drum roller you can get. If you are filling utility trenches on a congested job site in Georgia, you will want a mid-size tamping-foot (padfoot) roller with more maneuverability. If you are building a large 20-acre pad for a new shopping center, you may want a sheepsfoot roller.

Frequency and Amplitude
Bomag says that large vibratory rollers usually offer a choice of two amplitudes and two frequencies. That allows the contractor to adjust to job-site conditions. You would use high frequency/low amplitude on granular material or thinner lifts—and low frequency/high amplitude on cohesive material or thicker lifts.

There is little advantage to running a vibratory roller in static mode on soils or base material. A sheepsfoot roller, on the other hand, always runs in static mode and uses manipulation and impact to achieve compaction. Caterpillar Global Paving, a leading compactor manufacturer, says most of its machines are equipped with one standard frequency.

Variable frequency is available as an option.
Frequency is a measure of the number of complete cycles or revolutions of the eccentric weights around the axis of rotation in a given length of time. Frequency is usually expressed in units of vibrations per minute (vpm) or hertz (Hz). Amplitude is a measure of the vertical movement of the drum during a vibration.

The relationship between frequency and working speed, says Caterpillar, is sometimes simplified to a simple rule of thumb which states that frequency and working speed should be adjusted to yield approximately one impact per inch or 25 mm. Too high a working speed can cause “washboarding” with impacts spaced too far apart; and too low a working speed negatively impacts machine productivity. There is an optimum working speed and frequency for each compaction application, but they may not yield exactly one impact per inch. That is due to many variables of soil mechanics and composition.

Frequency is not so important by itself, says Jon Sjoblad of Caterpillar Global Paving. Traditionally operators use a process of trial and error to find the balance of frequency, amplitude and ground speed that most efficiently compacts the soil at hand. Operators adjust the speed and amplitude as they work, says Sjoblad.

An operator can sense when over-compaction has occurred. When a soil becomes dense, as it nears its maximum density, it deflects some of the impact energy from the drum and transmits it back into the drum. The drum will rebound high enough for an entire cycle of the eccentric weight to occur without the drum making an impact. In essence, the drum makes a “double-jump.” Such a phenomenon, called “decoupling,” or “double-jumping,” is easily recognized by the operator because it causes violent vibrations throughout the machine. To stop it, the operator will adjust amplitude down.

There are a number of compaction meter devices that can help an operator determine when proper compaction has occurred. Caterpillar’s AccuGrade Compaction is one such device, but it is a far more complex system than simply a compaction meter. Bomag Americas, Caterpillar, Dynapac, Hamm, and Volvo Construction Equipment all offer complete lines of soil compactors.

Volvo’s Lineup
Volvo Construction Equipment offers a full line of both vibratory smooth drum and padfoot compactors. Volvo acquired these compactor lines in 2007, and their legacy is traced back to 1969, says Bob Marcum, segment manager, Volvo Road Machinery.

The majority of Volvo’s vibratory soil compactors have five frequency settings. “This allows the optimum match of drum frequency to the natural resonances of the type of soil you’re compacting,” says Marcum. Frequency settings range between 1,200 to 2,500 vpm. Volvo vibratory soil compactors, seven tons and larger, have two amplitude settings which can range from 0.015 inch up to 0.080 inch. Higher amplitudes allow the compaction of deeper lifts of materials for more production.
Most Volvo compactors have a traction enhancement system for maximum gradability. This system ties the power of the front drum to the rear axle to enable the machine to climb steeper grades. “We have more centrifugal force in our compactors than most of our competitors,” says Marcum. “Greater compaction energy can provide increased production on difficult materials.”

All I can say is WOW. I am a teacher and a coach so I dont have a ton of time to check my computer. I was gone 2 days and I get great advice. Like I said before I got my masters in Biology (specific environmental) so I know a little of what is going on. I love the environment. Rainman thanks so much for the name I will look him up. I know a lot of people from that town. Great little farm town. Again guys you dont know how much I appreciate it. I am trying to do as much homework as possible because I am not made of money...I am a teacher..LOL...
What I really got from you guys is dont be afraid to go deeper. Hey if the soil was right I would go way deep but since it is gravel I am really nervous to go deep...

Definately go deeper, but keep good clay in reserve to make a liner. You won't regret it.

Good advice ! I have had bentonite work but it was not used over gravel but sand. If the clay is good enough quality you will not need bentonite. Bentonite is clay.

Betonite acts as insurance in marginal soils with some clay. Applying and incorporating bentonite requires experience. Choose the contractor wisely after good homework. IMO bentonite is most important where the clay liner is the thinnest and on the bottom where the greatest water head pressure is located. Remember just compacting soil lifts with weight is not inter-knitting the two layers together. Water under pressure can push its way through two compacted sheets of soil esp in marginal soil with low clay composition. All a pond needs for a leak to occur is to have just one relatively small area with low weakly compacted clay. Sometimes it takes several years for a leak to fully develop. Shore damage due to animal digging activity, wave action, or erosion can encourage the leak to fully establish itself. Two feet of compacted clay is not very thick when it comes to having shoreline tunneling animals present.

I dont know guys. Your kinda turning me off to getting a pond. I can see it is a big decision. I just want a little pond to swim in and if possible fish....thanks for all your great ideas...

A lot of really, really good info on this thread!!!

Don't chicken out thor, you'll be sorry .

Ok guys I dont know if this changes things or not but me and my family had a sit down talk and the main reason they want a pond is Swimming. Now now now dont go crazy but I have 2 girls and one is a really great swimmer. She just wants a 10 foot pond that she can swim in. Not very big...I would say a pond that is about 100 feet by 100 feet. Is this possible. They guy said he dug about 8 feet down and got great clay..got to 9 feet gravel. Can we elevate it and make it about 12 feet and put chemicals in it for a swimming pond? Is there a form for that here or can you guys help...I did call Ted Lea from Waynsfield. Has not gotten back with me yet..thanks

If properly designed, you should not need chemicals for a swimming pond. My kids learned to swim in our pond, and my daughter swam competitively all through high school. A floating dock with a swing-up ladder sure was nice for swimmers. This allowed diving and eliminated disturbing the mud on the edges getting in and out.

If you want a swimming pool pond, then you have 2 options.

1) Put in a natural swimming pool pond. You can't go about it half azzed. You gotta do the whole ball of wax. Here's some reading for you:

http://www.inspirationgreen.com/natural-pools-swimming-ponds.html

http://www.houselogic.com/photos/pools-s...re-expensive/#.

http://www.totalhabitat.com/natural-swimming-pools.html

2) Put in a traditional swimming pool.

You can't dig a hole in the ground and treat it like a swimming pool with chemicals, etc. It won't work.

The other route to take is to make a pond like we described and put in fish to keep the bug population down. I'd go with fish that don't reproduce (or have limited reproduction).

Redear Sunfish to minimize any possible snail population

A handful of Hybrid Striped Bass to cut down on RES fecundity.

Or a LMB only pond. There are other options - I'll let others chime in.

If you elevate the pond, you have to have a source of water to keep it full (even if it seals like a bathtub you will have evaporation). I'd still dig it deeper, save the clay and once you are down 14'-15', put 2'-3' of clay back in it, compacting it properly as it's placed.