Pond Boss Forums INTRO Questions & Observations Building 1 Acre Pond (High Water Table)

Hello All,

Looking for some advice as my pond dig is currently undergo. I am having a 1 acre pond dug out below my house, 15 foot deep in the middle. I am running into ground water at about 4-5 foot under ground. This is not a surprise as there is a small (4 foot) wide stream that is 30 yards away that trickles water through the year. I am trying to contemplate my lining / sealing options for maintaining a 10 foot plus pond depth. I am most likely going to put in a well, I have an old barn that I would like to have water to so its a win/win to install one with the pond.

Does anyone have experience with putting a pond in with loom soil and the above conditions? Appreciate any feedback/help I get. I have a clay contact that lives close and will allow me to use all I want. Only concern is with the high water table is that it will wash it away / make it not work. Also with a liner, I have read about all the troubles with them "Ballooning" in high water tables.


Thanks,

Luke

Good luck sir!

We are building also and it is very involved!

Welcome to Pond Boss, Luke.

Most of the "generic" discussion on the forum about building ponds is for sealed ponds that are filled via surface run-off (rain). Your project is of a different type.

Do you know how stable the groundwater table is on your property?

If it is stable enough for your purposes, then you could actually just build a groundwater pond that is connected to your local aquifer.

However, this pond will always look a bit "strange" since the water level will (usually) be 4 feet down in the bowl you excavate for the pond. A supplemental water well will NOT work in that situation. Any water you add will slow/ly/quickly seep into the aquifer and your pond will return to that water elevation.

If the groundwater pond idea does not work, do you have any clay available on your property? If yes, then if would probably be more affordable to use that clay to make a sealed type pond. If you do not have enough watershed available to keep that pond full, then your supplemental well would work.

If you do not have good clay close, then a pond liner would probably be your best and most affordable solution.

You are correct that a pond liner may balloon in a high water table situation. The physics gets a bit complicated, but the simplified version is that if you keep the water level in your lined pond higher than the "unrestrained" water level of your aquifer, then you should not have a ballooning problem. (If there is lots of high ground nearby and you have a partially constrained aquifer, then it is possible to have ballooning.)

There are some vents and underlayment drains that can be installed to address the problem, but most (all?) must be installed during the initial construction.

I wonder if you could just bury a length of corrugated plastic "drain tile" pipe in the sand across the length of your pond before you install the liner. Run the end into a little pit or vertical culvert. During a wet spell, you might be able to pump down the groundwater directly beneath your pond if needed.

I am not a liner expert, but we do have a few in the forum. Keep reading some posts to learn some more background. If you do end up planning a pond with a liner, maybe come back and get some advice from the experts during the planning stage.

Good luck on your new pond project!

Thanks for the feedback,

Is there an issue with doing a clay liner with a high water table? You have mentioned that and I believe right now that a clay liner would be my best bet.


Also for the drain tile, would there need to be an "electrified pump" installed with this? Ideally wouldn't like to mess with electric if I don't have to, I feel like the sump pump for the pit would be going off all the time as well.

Thanks!

The only issue with using a clay liner with the high water table is getting and keeping the clay the correct moisture content so that it can be properly compacted with a sheepsfoot roller in multiple lifts. (total clay thickness should be 18"-24". In your situation with the high water table that will be difficult to do but I don't think it would be impossible. Dig a deeper "sump" and have the water seep to that area while you are placing and compacting the clay. Keep the water pumped out of the sump and make the sump the last thing in the pond basin that is sealed.

With a membrane liner, that should be covered 12"+ with dirt anyway, so that might be enough to keep it from ballooning until you get water in it. The dirt over the liner doesn't have to be compacted, just put in place and have the slope of the pond sides gradual enough that the dirt won't slough off and slide to the bottom of the pond when the water is added.

Once the water level in the pond is higher than the water level in the surrounding ground, there will be no ballooning because of the higher water pressure in the pond vs. the water pressure in the dirt.

The "tile" suggestion while you put dirt over the liner will work great. Have the tile terminate in a pit that is deeper than the total depth of the tile under the pond and keep that pumped out while the work is being done to cover the liner. Then you can pull the pump and fill the pit.

Using a well to keep the pond full will work too, but the well has to pump more gph than the pond leaks, and you have to be willing to pay the monthly electric bill.

I have a ground water pond that can have the water level drop 9 feet lower than the normal "full pool" water level. It will leak more than 20+ GPM at full pool once the water table starts to drop. .

No issue with the clay liner (unless you have very strange circumstances). Basically, if you get your pond sealed with clay, any movement of water through your aquifer will try to go AROUND your pond.

The big issue will be CONSTRUCTING your pond in an area with a high water table. Wet ground is always a hassle for heavy construction equipment. Wet ground with clay involved is even worse.

Your contractor may have to dig a deep pit above your pond location and run a big pump to draw down the groundwater enough to excavate and line your actual pond location. That is feasible for many groundwater tables, but will add to your expense. (It will also add to your expense even if you do a liner pond.)



I was thinking that a high ground water table ballooning your liner would be a "rare" problem. I have a 2" gas-powered trash pump that I use to occasionally move water at our property. (Cheap one like mine is currently $450 at Tractor Supply for 150 gallons/minute.) They work very well in that type of application. I have filled mine with gas and left it running while I did other work at the farm.

Thanks for the info:

With your ground water pond dropping as much as 9 feet, do you have fish you are able to keep alive ?

Yea, I'm just trying to figure out which pond sealing method to go with. Both seem to have their draw backs in my situation.

Yea,

My contractor knows ... its been a pain and will continue until completion with how wet it is. He has a 12-14 foot spot dug out that he has been pumping out water while he has been taking away soil from the other area of the pond. I suppose at this point I will just have to wait until the entire pond is dug out and we can take a look at where any potential water is coming in before deciding which options might be best.

I have my contractor working on a quote now to haul in / put the clay down. I also received a few liner quotes back from various companies and it seems like a liner would be the cheaper option at this point. My biggest fear is the bubbling effect it can have. The companies I have received quotes from haven't been to helpful on advice with the situation... they just sell the plastic I'm told haha.

esshup's response had not yet posted when I started typing my 6:33 PM response. That is why I kind of covered some of the same points that he did, but in a slightly different fashion.

I was NOT correcting esshup's response. He is an actual pond expert!


P.S. My groundwater ponds also fluctuate quite a bit (4-5 feet). Are you wetter than usual over the past year? If so, it may be time to release your contractor for now, and have him come back after a hot, dry summer.

The demobilization costs for moving his equipment out, may be significantly less than the additional cost/hours that he has to put in fighting wet conditions. It never hurts to ask him.

Oh yes. When I renovated the pond, I knew that the water level would fluctuate, so I dug it 21' deep. Not a week after the equipment moved off the property, Hurricane Ike rolled through and dumped 12" rain in < 24 hours washing almost 3' of sand back into the pond.

When the pond was 9' low, I removed close to 100 pounds of fish to lower the biochemical demand on the pond for the winter, and made sure that the aeration system was running at all times.

That's the problem with 2 people typing at the same time! LOL

FYI, a pond construction project that I consulted on had a really, really GOOD dirt mover. His fix to digging a pond with ground water? He would put a french drain all around the perimeter of the pond construction area about 25 feet away from the perimeter of the pond, 5' deeper than the max depth of the pond. Then he'd attach risers to the french drain and hook up pumps to pump the water out. Pricey, but it worked and they didn't have to touch a thing once all the pumps were installed other than to fill them with diesel fuel and prime them if they lost prime.

When the project was completed, he'd dig 5'-10' down at each riser, cut the risers off and backfill, leaving the blocked off french drain in the ground.

Great stuff guys,

I have a contract that I signed with him on agreed overall price so the fluctuations will be on him (fortunate / unfortunately ) with the weather patterns. I have made it clear that I am in no hurry and just want the pond done the correct way. Unfortunately, we have had a wet / snowy start to December (I live in Indiana) so the project has already been a slow go. Again, being in December there is no rush for me to get it completed as I can't use it for anything I would want until the weather heats up. Appreciate the feedback so far, Hopefully in the next 2-3 weeks my contractor will have the pond dug out and I can see what kind of situation we have moving forward. He currently has a 12-14 foot hole off to the side that he is pumping out of as he digs... this freezing weather and snowfall has been an additional challenge.

I built a pond in clay that had a massive amount of groundwater coming in. We could only get down 8' because it was coming in so fast, and this was at the end of summer too. We never compacted the clay, or even ran it over too much with the dozer as it was all applesauce from all of the water. This is a re-dug pond with only a little 2' dam. The pond ended up 5' deep with zero rain. By early fall it was using its 8" overflow pipe. The pond builder wanted to use 8" pipe for this small .4 acre pond because of the water. We had a drought last summer where my other pond dropped a foot. Ponds uphill of mine dropped 3', or more. The .4 acre pond? Never dropped an inch.

Willy,

Did you guys every have any ground pumps running to pump the water out as you dug?

Yes, we did, but it was coming in faster than the pump could keep up. We had hit 8' deep at the point, and it was very sloppy. We figured that 8' is deep enough. We have dug three ponds on my property and have yet to hit 10' due to water flooding in. The good part is that my ponds never drop more than a foot no matter how dry it is. We are in the snow/rain/sleet/gropple belt of NE OH, so there is very little sun, (like 60 days of it a year) and lots of precipitation thanks to Lake Erie, so evaporation is not much of an issue here.

Thanks for the additional information, Willy!

Construction-sized trash pumps can move an immense amount of water. However, at some point the battle becomes too great and you have just settle for what the ground conditions will allow.

Luke,

Does your contractor's sump hole quickly draw down when he turns his pump on in the morning, or does he run it all day and barely pulls down the water level? That kind of sets the parameters for his "battle" against the groundwater.

When he has the pump running the water level does go down substantially in the pit he dug. We have yet to get a 2nd pump going with where we are on the project but I'm assuming as we go deeper we will need to get a second pump going. Still digging up the 3 feet or so of top soil off the grid of the pond currently.