Hi,

I live in Central New York (zone 5b) and have a contractor that pushed back my pond build to winter. He's planning for February. I'm wondering if anyone sees an issue with digging a pond at this time of year. A neighbor of mine has said he'd be concerned about compacting the frozen ground and heaving issues. The soil here is very heavy clay and we're surrounded by ponds.

Thanks!

Shawn

Shawn, welcome to Pond Boss.

Ideal situations are to be able to work the pond basin when it is free of standing water. I could see some scheduling benefits for the pond builder to do the excavation during the winter, but my guess would be that the finish work would need to be done in warmer temperatures. If the hole was dug in the winter, I would think you would start to accumulate some water before the finish work.

I have no expertise on this, however, so let's see what others have to say.

Your concerns are valid. Get in touch with other pond builders in your area and ask their opinions. Trying to compact frozen ground is a tricky proposition.

I am NOT an expert, but I believe the biggest construction problem when dealing with heavy clay is excess moisture.

It would be possible for us to do that type of project right now in Kansas because there is only a few inches of frozen ground and our groundwater levels are very low. February is usually a dry month in Kansas, so that also helps.

However, in central NY, your maximum frost line should be around 50-60 inches! It won't be quite that deep at the start of February, but it should be close.

I can't imagine how much extra work will be required to excavate under those conditions. Further, you cannot properly compact fine-grained material when it also contains cobble-sized chunks of frozen material that remain after the contractor ripped with a dozer or dug it with an excavator!

I think you should push him back to spring, and ask him to schedule in the sweet spot where the ground has thawed and you don't have spring rains in the forecast in the time period expected for him to finish the pond. (He may want to work now to avoid dealing with wet clay due to spring rains, but I don't see how the contractor can alleviate the frozen soil problem.)

Good luck!

Thanks for the responses from all of you. With this soil and the typical rains here, there is no dry window in Spring, so perhaps it's best to wait until summer. I'll see what the contractor says about the compaction issue. I had him at my house yesterday to review the site and he didn't give any indication of winter issues. Trusting his work ethic, but many up here are saying digging a pond in February just doesn't make sense.

There have been many stories on Pond Boss about good dirt contractors with good work ethics that still can't build a pond that doesn't leak.

I have no idea how much of that applies to your contractor! However, it would be nice to learn if he had built other ponds in the area, with similar soil conditions, in February, that did not leak.

My father has an excellent cardiologist because he has lots of heart problems. However, he turned to a different doctor for his knee replacement! I think our best advice is that you need to make sure your "pond guy" is an actual "pond guy".

Digging a pond during winter in my area would be a no-go, not only due to compaction issues, but also too much water in the ground. Ponds typically need to be built based on the weather and climate rather than around the convenience of the contractor. IMO, it's better to wait until you find the right contractor who can do the work at the right time. Maybe that is not true in your neck of the woods?

Thanks again to everyone. I talked to two other pond diggers today. One said a no go in winter and the other said february and march are not the best times because it's the only chance to access the clay around here that has been saturated by an abundance of rain this season.

I do trust the guy who wants to dig in February. He's shown me his ponds, and has been digging and doing work for 30 plus years. He's done the excavation for my home and driveway, and then a french drain.

I'll have an open talk with him about others' thoughts and see what he says. It does a feel a bit like he's trying to squeeze this in between other work. I turned to this forum because I want to do this right the first time, so really valuing everyone's opinion.

To give an idea of how what and high my water table is, I dug a 2 foot trench by hand this summer to run electric to an outbuilding I built, and after 2 hours the entire trench filled with water. The water table is constantly high in the area I plan to put the pond, and the ground is always wet. In my eyes, a perfect pond site.

It does sound like a perfect pond site - except for the portion of the construction phase where the contractor is trying to drive a dozer on wet clay.

However, we did not ask some important questions.

How large is the proposed pond? Embankment type (with a dam) or an excavation type?

Finally, how is the contractor's bid structured? If he is doing the work for a fixed price, then it doesn't matter to you if he has to fight the weather during the job. It is probably a good deal for both of you to fit this work in when the season makes his other contract work slow down.

However, if he is charging by hourly or day rates for his equipment, then the weather hardships come out of your pocket.

P.S. Do you have a lower location on the property to allow for drainage of the groundwater from the pond site during construction? This can be either by a cut trench or by pumping. The hole filling with water will make excavation, moving the spoils, and compaction more difficult to achieve.

However, if the groundwater level is at roughly the same level during all four seasons, then you will have that battle regardless of the time when you build the pond.

The upside is that you will always have a full pond, which will give you much less stress when you are managing your fish!

Thanks again for your input and advice.

The planned pond will be about 1/8 acre with a depth of 10 feet. It will sit upslope from my home and will be excavated. When we walked out the planned perimeter, he had estimated the pond berm would make a pretty significant hill that he would gradually slope down (I've seen this on similar ponds in the area).

There is a plan to run the spillway out to a part of my property that has a significant dropoff into a creek, but there wasn't a discussion about mitigating water while the pond is actually being built.

I think my biggest concern is can this soil be compacted properly when frozen? Once the excavation gets beyond our 4 foot frost line, it won't be frozen, though once exposed to the air, it will be (5 degrees here this week).

It's a flat quote for the pond (5k), including a gravel beach area, a shelf for my kids to play on, and raking for me to seed. Other quotes were 8-10k, so this one is hard to pass up.

Some great questions and answers.

Is the water source for the pond run off, well, springs, or water table? I'm not sure I saw that in the thread.

He could dig a sump and let the water run into that, and keep the sump pumped out during construction. An 1/8 acre pond he can compact it with a sheepsfoot attachment on the excavator arm. Not the fastest thing in the world, but for something small like that pond, it should be able to be done. It all depends on the temps too. He could get the majority of the work done, come back after the thaw, pump it out and finish the work.

high water table and there are a few little springs running through the pond area, plus there's just an insane amount of precipitation where we live. There's a pond in all directions from me, including a small 4 ft deep pond on the southern part of my property, put in by U.S. fish and wildlife before I owned the land.

The pond will be higher than my well, which is a about 35 feet deep. I've been wondering if this work could change the flow of the water feeding my well, but the excavation won't go that deep.

If you are relying on primarily the water table to fill the pond, I think that maybe changes things a lot.

When everyone was bringing up compaction, and the possibilities of poor compaction due to cold temperatures, that line of thinking was in order to keep water IN the pond. The same line of thinking would not allow water enter the pond meaning that if you seal something one way, it's sealed the other way too.

If it's as simple as digging a hole that will fill with water, maybe it can be done any time of the year.

I like the project better with two of your answers being: fixed cost and 1/8th acre pond.

The contractor will only need a small window in the spring to finish that pond if he can't get it compacted during February.


The shallow springs running through the soil and the groundwater feeding your water well, should be two separate sources if your description of heavy clay soils is accurate. (Pro tip: Beware of geological advice given over the internet. It is worth exactly what you paid for it!)

The thing I don't like is that the pond is upslope of your house. If the pond does leak, then the water is going to get back into the "little springs running through the pond area" and potentially work up against your foundation.

I just saw Sunil posted while I was typing.

He brings up an excellent point about "groundwater" ponds.

Most of the replies to your post have been good advice for typical ponds across the U.S. However, many (like mine above) do not apply if your pond is going to be a true groundwater pond.

At my farm, it is about 6' of digging to reach the small springs in the soil. However, the topography is so flat, that the water level from the springs only pushes up about 6". If I tried to create a "groundwater" excavated pond, then the water level would always be 5 1/2 feet below the banks of my pond.

"To give an idea of how what and high my water table is, I dug a 2 foot trench by hand this summer to run electric to an outbuilding I built, and after 2 hours the entire trench filled with water."

It doesn't matter that the "whole trench" filled with water. What matters is whether the water rose up to the top of (or even flowed over) the edges of your trench. How high did the water go in your trench project?

If the static water level was high, then your contractor has an easier job than most of us thought. It also explains why he said he could do the job in February. He just needs to excavate the pond and partially seal the down-slope side of the pond enough so that the rate of downslope leak + evaporation is less than the rate of spring water inflows. (If your springs are really prolific, then he doesn't need any seal.)

That is an easier task to accomplish. Although, I am still a little leery about doing the work in February.

thanks again to all of you for the feedback. I've attached a google map mockup of the site. The plan is to run the water off to the creek on the west. the land slopes from northeast to southeast. south of my house is the septic, east is an orchard I planted, so above house is really the only option.

The outbuilding in the back is a sauna, so ideally the pond would run close to the sauna with a dock going right out the door and into it.

My house is on a concrete slab and I do have a drainage ditch around the northern perimiter to bring water away, but not sure if that would help if a pond berm broke away. In addition to swimming, fish, and overall beauty of a pond, I'm hoping the pond can help mitigate wetness downlsope of it.

Here's Shawn's picture:

We built my 15 16 acre pond in the middle of winter, 3 yrs ago, usually that would not be a preferred timeline but it worked out great for us, the frost was not a problem, we started when there was only a small amount of frost in the ground and set it off to to the side and used it on the back slope when thawed, other then that he most likely wont be working equipment when it is near zero, he cant the dirt will freeze to his blade and bucket. I would definitely not condone trying to work the dam when there is frozen chunks of ground present. the water can be an issue but I put a 4" drain line in the bottom of the pond for water removal and then just closed the valve on it after construction was completed, and now I have an awesome water source behind the pond to fill a tank or anything to water gardens, trees or even animals. wouldn't build one without it, plus by putting a watering pipe through it in this area qualify s it as a agricultural pond for livestock watering and the government is waaay more lenient to farms and farming requirements then they are for pleasure ponds.
Keep in mind that the size pond you are talking about for that amount of money will be completed in a couple days, as compared to the three weeks we were working on mine, he can hit a window of nice weather and have it completed before the next front moves in.
My point being I would not at all be afraid to let him do his thing, it worked perfect for us, I just completed a pond in late Dec for a customer, obviously we have had extremely nice weather here locally and it was just a few day project, there was no frost in the ground under the sod and no harsh weather predicted for a week so we finished it in no time before the weather took a turn. Its our free time, most winter we don't expect to be doing anything but shop maintenance in the winter months.

gehajake, thanks for your input. Good to hear from someone that's done some successful winter ponds. I like the idea of the drain line.

My father has built several ponds here in MidMichigan. He built our pond in the winter. It was actually much more efficient since the surrounding top soil was frozen well enough to allow him to drive his 50 foot reach excavator farther into the pond area without the need to lay mats. The digging itself was much faster and cleaner. The area where our pond is used to be a bog. Summer digging would have been a wet, sticky mess and the clay tends to really stick in the bucket of the excavator. Digging in winter meant that each scoop could go directly into the dump truck without having to pause while the water drained from the bucket nor having to stop repeatedly to scrape the bucket. It should be noted that the frost only penetrated down about 3ft. so there was no problem with smoothing the bottom with clay since it wasn't even frozen at that depth.

Thanks for the reply, Dreamcatcher!

That is an excellent example of using the weather conditions to your advantage during the pond construction phase.

This is reassuring. The conditions you describe are similar to mine, and it's the rationale provided by the contractor. Although our frostline is 4ft, I can imagine it doesn't get that deep anymore due to the gradually rising temperatures here (first and last frosts have been 2-4 weeks further in and out for years here.

My only thinking is that whatever is exposed underneath and left over night will then freeze by the next day, depending on the temps here (it really can vary in february)

Thanks again!

Shawn,

If they are working in very cold air temperatures, then newly-exposed subsoils will cool off overnight. However, they should not be capable of freezing to any significant depth.

If his equipment has sufficient break-out strength to get through your existing frozen soil, then overnight freezing will be no problem.

If your contractor is capable of excavating to START your project in winter, then it should not be a problem to finish excavating. I think many of the replies you received were from people worried about getting proper compaction (if needed) for a pond created during winter.

Plus with a pond that is 1/8 acre, the excavation and work will be completed very quickly.

I honestly don't think it will be too much of a problem excavating, but the thaw in spring is going to be difficult to deal with. The clay is going to move and flow as it thaws. What you think is compacted, is not, as water from frozen groundwater mixed in clay perks up and out as it thaws and settles. It will be impossible to walk on for a while (try snowshoes) until things dry out a bit. If you decide to go for it, lay down hay at minimum, erosion mats would be best to hold everything in place as it thaws.

Right now things are very cold, and my pond has near 10" of ice. Meaning the soil, if exposed, is frozen that thick also.

Me personally would go for it, and deal with the slop in the spring with erosion mats.