Dirt Moving Big Hole

[Diamondcutter]

I have a Ford 550 backhoe and I am trying to dig my pond down as deep as I can get it...hopefully 30 or 35 foot. I want to keep the walls as steep as I can with one pathway out (perhaps 200 feet or more long). So far I have been using the front end loader to dig. Would it be better to use the back hoe to pull down dirt from the walls before scooping it up? I can usually get a full load with one or two strikes but the ground is heavy clay with large gravel and it is getting harder. I want the pond deep to give me stable temperature water to use for geothermal system in my future house. Any advise would be appreciated.

 

[Gary Fowler]

If you have clay soils, anything more than 45 degree slope is just going to collapse into the pond when water fills it anyway due to wave action and softening of the clay. Vertical walls are only good in stone or other very stable materials. Taper your walls according to the angle of repose for dry material of the type soil that you have.
I would dig with the FEL rather than the hoe if you can get a full bucket. I dug a small pond using the FEL and a boxblade with scarifiers. Using the scarifiers to loosen up harder soil and rocks then attack it with the FEL. With a little coordinated effort, I could drop the box blade and loosen up while loading up a bucket with the FEL making one pass work for two tasks. The backhoe will dig out harder material than the FEL but try the boxblade and lower the scarifiers as far as they will go, that is assuming that you have one. You will have a huge pond if you get it 35 feet deep assuming a 45 slope, each side will be 70 feet plus what ever you get for the flat bottom. SO if it is like an upside down pyramid that is 140x140 minimum and at least one side would have to be double that to get down to an angle that you can climb your tractor out of. Maybe you should think of terracing it like a strip mine and forming a spiral road up and out.

 

[Mechanos]

On a related note: I believe that you need 1/4 acre of pond (at depth) for each ton of cooling needed.

 

[KenKubota]

I wouldn't go near even a ten foot vertical wall of clay and gravel. If I undersand your description correctly, your pond will likely end up contaminated with diesel, oil and human remains.

 

[MarkV]

The other thing I would be concerned about is digging through the clay layer that will hold the water and getting into a layer that will not. 30 -35 feet would not work in my area. Make sure you know your area. When you say the ground is getting harder...if that means more rock ledge...that is more pores than clay and can drain a pond.

MarkV

 

[Diamondcutter]

Thanks for the great info. I am totally new at this. Do you think I'm ok at trying to go down that far? I don't want the overall surface area to be too big as the area where I want is is only about 4 acres and I want my house next to it about 200 feet away. I'm not planning on a conventional heat extraction geothermal system. I want to build my own using a series of radiators in the heating & cooling system intake space. I think the water in the bottom of the pond should stay around 60 to 70 degrees year around in my area of Southwest Arkansas.

 

[Diamondcutter]

Thanks!

 

[Diamondcutter]

The clay and rock mixture seems about the same as I go down. It is just more compacted. Thanks.

 

[Diamondcutter]

I don't plan to get steeper than 35 to 45 degrees and I'll stay away from that on my tractor. I want a long slooping channel leading down into it.
Thanks,

 

[Gary Fowler]

I dont think you will need to go nearly that deep to keep the water at 65 degrees. I remember when a boy that diving into deep water, I didnt have to go very deep to get frigid even on hottest days. I would think 15 feet would be plenty but consult some of the experts in the area that do those ponds for advice. I know you dont need 35 feet for sure. You will likely hit ground water at about 10-12 feet and then you may have to stop anyway.

 

[MarkV]

You might also do some checking on this site. Pond Boss Magazine: Welcome There is a pretty good crowd there and some of them are pond builders.

MarkV

 

[case245]

i have a clay dam its 200 feet long 70 foot wide 8 to 12 foot deep the straight side holds the water in the breast that a 90 degree wall with big rock some weight 2 t0 4 ton no problem with it since 1984 when it was finished clay ground will keep the water brown it was dug with a dozer i would use your hoe to oull the dirt away from the walls that the easist route

 

[Diamondcutter]

Thanks. I too once dove deep enough in a pond to hit the first thermal layer. That's usually at about 12 to 15 ft. In a larger lake, a second layer usually starts at about 20 to 25 ft. The reason I want to go so deep is to get enough volume since it will be an unside down pyramid and I am limited on the surface size. I hoping for 30 feet from ground level since the water level will probably be 5 to 8 ft down. The area is almost flat so I won't have a levy. I want to use an open system where I extract water from the bottom and return it midway or top according to the return temp. I want to run the water through a sand filter, my heating/cooling system and then through a large aquerium before returning it to the pond. My house will also have solar hot water heating coils on the Southern facing roof. A Darious windmill and solar panels will help generate the electricity I will need to run the pumps. Most of this I will build myself, if I live long enough! At least I can dream about about the completed project. My pond is about 10 foot deep and a hundred or so feet wide now. At least a start, right? I appreciate everyone's advice and redcommendations.

 

[crazyal]

One thing you can do is put large crushed rock on the steeper slopes to help prevent the clay from migrating to the bottom of the pond. Around here we call it rip rap. As far as using the backhoe goes, do you have teeth on your front bucket or is the edge flat steel? If you don't have teeth I would look into a tooth bar for it. The backhoe will work but it'll slow you down some. I would say try the backhoe.

 

[creekbend]

The other TBN members have offered great advice. I would like to add this important advice. Please be careful. Best wishes.

 

[20 20]

The rule of thumb is 1foot down for every 3feet out. You also only need to be 12 feet down for geothermo. 35' deep is a long way down and a major amount of spoils to move, how deep are you now? As some one wrote you may work right through your clay and into something else that may not hold water especially if trying to go that deep. But if you do happen to do that you could all ways bring back a layer of clay to coat the pond.

 

[Redneck in training]

I have a Ford 550 backhoe and I am trying to dig my pond down as deep as I can get it...hopefully 30 or 35 foot. I want to keep the walls as steep as I can with one pathway out (perhaps 200 feet or more long). So far I have been using the front end loader to dig. Would it be better to use the back hoe to pull down dirt from the walls before scooping it up? I can usually get a full load with one or two strikes but the ground is heavy clay with large gravel and it is getting harder. I want the pond deep to give me stable temperature water to use for geothermal system in my future house. Any advise would be appreciated.

I worked in Arkansas several years back and remember there was snow on the ground. Therefore I doubt the water temperature in the winter will be 60-70 deg regardless of the depth of the pond. The geothermal will actually work well even in a small puddle but the problem is it will affect the life in there. The temperature will go up in the summer and down in the winter. Therefore there is a rule of thumb about sizing the pond versus the size of the system. I would, in general, advise against open system. It requires maintenance. The marginal gain in efficiency is not worth the complexity and the trouble IMHO.
You also mentioned wind mill. If you look at current cost of solar panels there is not a windmill that can beat the cost/W of PV even when you make the windmill by yourself. Panels are about $1 to 1.2/W while complete DIY PV system will run in about $2,10 - 2.25/W.
If I would build my house today I would install split heat pump units to every room and power it with solar system. My cost analysis is that it will cost just about as much as geothermal while energy cost will be pretty much close to zero.
1 ton split unit is about 2200 DIY or 3500 installed. Three bedroom house needs four or five of those.
20kW DIY solar system will cost about 30000 after government tax incentive.
The total cost is more than geothermal system but with no energy cost.

 

[Diamondcutter]

Thanks. First hard figures I have looked at. I do plan to do about everything myself. I'm retired and mostly want something to keep me active.

 

[weedpharma]

i have a clay dam its 200 feet long 70 foot wide 8 to 12 foot deep the straight side holds the water in the breast that a 90 degree wall with big rock some weight 2 t0 4 ton no problem with it since 1984 when it was finished clay ground will keep the water brown it was dug with a dozer i would use your hoe to oull the dirt away from the walls that the easist route

G'day Case245. You may not have noticed but your "Shift" & "." key are not working.

Weedpharma

 

[Redneck in training]

Thanks. First hard figures I have looked at. I do plan to do about everything myself. I'm retired and mostly want something to keep me active.

Look at in example Halcion split units. They are super quiet and very efficient. They work quite well in Iowa and will work much better in your climate. If you don't know how to install them hire somebody to install one, then buy vacuum pump for $100 and install the rest by yourself. I paid for installation and I was not happy with quality of work. I plan on installing one more unit in my shop and I will do it by myself.