Pond Boss Forums INTRO Questions & Observations My DIY pond construction experience

I have been a nearly silent learner on here for a couple years now, and thought that I finally have something worthwhile to contribute to the vast amount of knowledge and collegiality that is here.

I am nearing completion on a 1.25 acre excavated (not dammed) pond in Maine. It will be used primarily for fishing with a little swimming and ice skating and is adjacent to our yard and the focal point of our 55+ acres. The estimates to get this done were $160k, which was shocking to a simple guy like me. For those with dammed ponds, it seems the cost can be exponentially less, but moving 16,000 yds3 of material is terribly costly. I had no experience taking on a project of this magnitude, but I have a strong work ethic (and don't have $160k burning a hole in my pocket), so I took on the project DIY. I bought a 2000 John Deere 160LC and a Morooka MST2200 (12 ton dump truck on tracks) and got started about a year ago.

I track my progress by dump truck loads, which I expect is about 9-10 yds3 per load, and I've moved just about 1200 loads of material so far and estimate that I have about 300 to go. Thankfully none of it will need to be trucked off the property. After about a foot of good topsoil, there is dense grey clay as far as I've dug (max depth 20'). I haven't encountered any ledge, sand veins or springs. The pond is fed by watershed and ground water and seemed to fill up as fast as I can dig it. I estimate at this point that I've spent about 40% of my time moving water and not dirt, so I've come up with some strategies to mitigate the water that I thought could be useful to others.

I bought two 9hp gas powered 4" semi trash water pumps that will move 25k gallons/hr each. I am currently running only one at a time thankfully. What has worked best for me is to put the pump in a small plastic "bass boat" that is tied off via ropes to opposite shores so it is centered over the deepest part of the pond. The boat hovers over the deepest end and goes down as the water level goes down.

The pumps came with a very small gas tank, so I went to YouTube and ultimately added a 3 gallon auxiliary gas tank to get longer run times. I've also found that running it at 2/3 throttle vs full throttle more than doubles my run time and doesn't decrease my flow rate much or at all. By making those two changes, I can run my water pump all night, top it off with fuel in the morning, and it's pumping for me as I'm away at work.

I found the 20' long intake line to be a beast to manage, so I built an intake out of heavy walled PVC and attached it with a Fernco fitting to the intake side of the pump. The discharge line is 4" lay flat line.

It seems that many fellow pondmeisters don't have enough water; I've been battling the opposite. For anyone else in a similar situation, I hope this works for you. Hopefully these attachments come through.

My shovel


My wheelbarrow


Water pump set up in the boat



If you're having trouble priming the pump, fill it with water, add something like this, and when you start it up open the valve. It will vent any air trapped in the pump first, then will start shooting water out. Close the valve and it should be pumping properly.

Great advice! I plumbed in a metal outboard motor tank to my pump, gravity fed. Those small plastic boats are pretty bullet proof.

Keeping the intake out of the dirt is key, it makes the pump last longer and you don't have the intake hose filling with sand/dirt.

How do you keep the boat in place on the pond?

Welcome Mainer. Pretty impressive wheelbarrow.

I have the front and back of the boat tied off to trees on opposite shores and hovering over the deepest part of the pond. As the water level goes down, the boat floats down with it. I use a kayak to get out there to start it and refuel it. It has worked well for me.

I was surprised to see the difference in running it at 2/3 throttle vs wide open. It seems I get the same flow rate (about 25k gallons/hr) but less than half the fuel consumption. A fried of mine is a firefighter and said that this is typical of a volume regulated (not pressure regulated) pump. I imagine there are some principles of physics at play.



This is what my "days off" have looked like for about a year, but I'm nearing the finish line.

Hard core!!!!!

Great report!!

Awesome job, Mainer!

You say you are excavating in clay, yet the pond keeps filling up with groundwater.

Clay is almost always an impermeable material. Something in your subsoils is connecting your pond to the groundwater aquifer. I am only asking so you get your final construction finished as you want it.

Where is the groundwater level in your pond excavation when you have taken time off from the seat of your excavator? Does it rise to an elevation that you would be happy with as the normal pool water level of your pond? If so, then you should probably leave your sides and bottom unsealed and keep it as a groundwater pond.

How much does your groundwater level vary between wet years and drought years? On my farm, it varies by over 15 feet! I cannot operate a groundwater pond as a managed fishery under those conditions. However, I expect the groundwater table may vary much less in your area. If so, then that further supports you choosing to have a groundwater pond.

IF, a groundwater only pond will match your needs, then you might consider excluding the surface water from big rain events from entering your pond. That water will bring silt, leaves, and potential thermal shock events to your pond. All of those are big negatives. You could easily ring your pond with a shallow berm based on how you are moving your spoils.

Finally, have you considered a small pond upslope of your main pond? Lots of people on the forum do great things in tiny forage/grow out ponds. If you are allowing surface water into your main pond, then you could use the upslope pond as a silt trap. Much easier to fire up your excavator and clean that out to full depth every few years, compared to slowly losing depth in your main pond.

Good luck on your fabulous DIY pond project! I am just throwing out some more ideas before you complete your finishing touches.

P.S. I am hoping to do a similar DIY pond project on our property. However, if you are going to post significantly more in this thread, I don't want to clutter it.

If you are so inclined, could you post here or in a new thread, "Lessons learned DIY excavating a pond"?

I will make plenty of mistakes and inefficiencies on my own project, so if I can eliminate one or two taking your advice, then that would be greatly appreciated!

Mainer, that correlates to what I saw with the dewatering pumps. I upsized my outflow pipe from 3"-4" going to plastic pipe as soon as I could. Running the pump at a bit over idle reduced fuel consumption further, but I saw about a 50% reduction in water moved. Using a 6 gallon outboard motor tank as a remote tank I could run the pump for about 28 hours on 3/4 throttle, and about 23 hours on WOT. I had about 250 feet of 4" pipe on the discharge side to get it further away from the pond.

We will be starting a project as soon as we can get the OK from the county, and the contractor said that if the project needed to be dewatered, they'd dig a 30' deep french drain around the perimeter of the pond area, backfill and connect the drain to surface pumps. Last project they did they used 6 diesel pumps, each connected to the 6" french drain system. It was not cheap they said.

The pond is almost exclusively fed by surface water via a seasonal (that is currently diverted so I have less of a water battle to fight). I have only seen this drainage go dry a month or two in the few years that I've owned the property. I expect there will be some ground water influence as well but that will probably be the minority. I base that thought on crude a test hole I dug a few years ago with a shovel. I went about 2-3' deep and a shovel blade wide, then let it sit for 15 minutes. When I came back, the water level was halfway up the blade on my shovel and seemed to be seeping in from the sides of the hole.

The vast majority of the water supply will be surface water via the seasonal drainage that I now have temporarily diverted around the pond. One scoop with the excavator will allow all of that water flow to go directly into the pond. Somewhere along the way I calculated that it will be about 3.8 million gallons at full pool, and I sincerely expect it will fill in less than a week, then start draining out the natural path of the seasonal drainage. That's a LOT of water turnover it seems to me. I collected a water bottle full to send to the university lab in Texas to be analyzed but haven't sent it yet.

I have considered the idea of a sediment pond upstream as well and could probably fit a 20-25' circle in the space I have without cutting down a bunch of trees. I am considering raising baitfish in it (common shiners and/or fatheads) and using them for bait as well as supplemental food for the fish. I'll need a cage of some sort to contain them.

The water flowing in is always clear (never cloudy), and ice tea colored. I haven't tested it with a Secchi disk yet but I will in the Spring. I suspect there may be some sediment in it that I can't see, so it's probably worth my time to have a place for it to collect and have easy access to dredge it out. Upstream is all woods so no need to worry about crop fields, fertilizer, etc.

I got about the first third of the pond dug before Spring last year, then deployed overseas for about six months. It filled in a few days and stayed full and overflowing via the natural seasonal drainage path the entire time I was gone. When I got back I was pleased to find that the shoreline weed growth was restricted to water 2' deep or less. I suspect that the tannin stained water is preventing sunlight penetration. I took a couple swims in it and was surprised at how cool the water was below about 2-3' deep. I thought that the darker color may absorb more sunlight causing the water to get warmer, but that didn't seem to happen. Maybe the water turnover rate is playing a big part in keeping it cool.

I was expecting a deep muck layer when I was wading and swimming but was happy to find that only 2-3" of the basin was soft. Deeper than that, it was completely dry. That's some dense clay!

My fishery will be SMB, YP and brook trout with bull frogs, calico crayfish, fathead minnows and common shiner as my forage. I found a shiner and a crayfish that found there way into it already, along with thousands of bullfrog tadpoles. I didn't take a temperature on the water this Summer when I was swimming in it unfortunately, but it seemed cool enough to support trout as long as I have adequate DO. I'll take any recommendations on a reliable DO meter that is also affordable.

esshup: I'm running about 200' of discharge hose. I suspect that since I'm pumping uphill about 15', I'm not getting the full 25k gallons/hr that my pumps are rated for but they are serving their purpose. Running six 6" diesel pumps at once sounds like draining the Mississippi River! That makes my water flow look like chump change! Hopefully they have much bigger digging and hauling capabilities than I have so they can tear into your project like a pit crew and get it done quickly. Burning that much diesel will get costly otherwise.

I sincerely appreciate the feedback from everyone. If I can help anyone else's project in any way, let me know and I'll be happy to share what I have learned after digging 0.9 ponds so far.

Tally at the end of the day today: 1214 dump truck loads of material moved in total, about 300 to go.

It's a fun piece of equipment, and I think the only way to get a job like this done unless I had a hundred crane mats or the soil was frozen enough to run haul trucks on it. This thing has a 250hp Cat diesel and even fully loaded with 12 tons of clay has only 6psi of ground pressure so it almost floats across the soft ground. It feels like it has enough power to climb a tree, but I haven't tested that yet. By the way, it will be up for sale when this project is complete. If anyone is interested, let me know.

Mainer:

Luckily on this project (once it's a go) we won't have to deal with the groundwater issue. The contractor had that to deal with on a previous project. He brought in an excavator and after the top 6' he hit nice blue clay all the way down to the 20' depth with no water issues.

The property owner will have a well dug to fill the pond and to keep it full. It will be a big project, 6.5 surface acres, 20' max depth.

Hi Mainer,

I too am in Maine, midcoast, and looking to build a pond in our backyard. Just getting started though, having done the research to buy a 2 ton excavator and should have that soon. Now need to turn to how to actually dig the thing.

First though, I'm wondering if you'd share your notes on permitting and regulations,
I'm told that, as I'm not near (150' I believe) a designated wetland than I do not need a permit.

Also, I'm wondering if I'm going to find clay in the area we're looking to dig, it has standing water often but that could just be where the shale is near the surface, no? Is clay a common material found underlying the ground cover in Maine? Are you seeing a lot of clay where you're digging or is mostly shale?

And, if there is no clay would this work anyway? Can you dig down into shale and have it hold or at least retain water?


Thanks,
KWL