My first pond build from start to (hopefully) finish

[killerbren]

Okay, it has been awhile. Time for an update....

We had alot of rain this spring, it seemed as just as it started to dry we would get more rain, but I pumped out that stupid hole every day. Good news is that the rains have stopped and we have finally gotten some really warm weather. Bad news is that the water refuses to stop. Im pretty sure its not coming in as quickly as it used to, but it is definately still coming in. So, after alot of thinking, a new plan needs to be made.

Im almost certain I wont be able to get the 4 feet of depth as origionally anticipated so I have two ideas.

1) dump about 1 foot of gravel in the bottom of the hole, enough to be able to make a firm base in the mud. Then place a 4" pvc weeping tile in the gravel to release excess water to the surface, where I could pump it out when overly wet in the years to come. Cement my bottom drain in the gravel, lay a layer of sand, then place the liner over that.

2) put my pvc weeping tile down first, then the liner, then lay the bottom drain on top of the liner and fill the bottom with 1 foot of gravel to level with the bottom drain. this way I could use the weight of the gravel to hold the liner down so we dont have any liner floating up.

any ideas? im tired of waiting for this thing to dry up when im positive that will never happen.

another option is to not have to deal with the high water table every year and have the pond be a nightmare. Fill the hole in and plant a tree, but im really hesitant to do that as that would be admitting defeat, and I want a dang pond in my yard.

 

[CountryEscape]

Go for it, Killer! You have two really great ideas there, and I'm sure someone will sound in and let you know what they think as well, maybe agree with your plans, or maybe have some better idea. I'm glad I didn't have to worry about that, although my water table is said to be high, it's not that high. Goo luck!

 

[Waterbug]

killerbren, you're making it very difficult for yourself. Make the pond water level at least 2-4" above the surrounding grade and you'll have zero future problems. No gravel, no drain pipe, no weeping tile, no sump pumps and you can make the pond as deep as you like.

I know terms like drain pipe, weeping tile, drain rock, etc., all sound good because they have the word "drain" in them but they only actually drain stuff if installed a certain way. With a pond level below grade there is simply no place for water to drain. Unless you add a sump pump and can move the water some place far away and down hill. But even then getting water out from under a liner with 4-10 tons of water pressing down on it is virtually impossible. Drain rock is going to be pressed into the mud, no problem. Then you'll have bigger problems because your pond will sink along with the rock.

This business about building the top of the structure (pond level) above grade is not something new. Swimming pools are built this way and so are home foundations for the very same reason.

 

[killerbren]

killerbren, you're making it very difficult for yourself. Make the pond water level at least 2-4" above the surrounding grade and you'll have zero future problems. No gravel, no drain pipe, no weeping tile, no sump pumps and you can make the pond as deep as you like.

I know terms like drain pipe, weeping tile, drain rock, etc., all sound good because they have the word "drain" in them but they only actually drain stuff if installed a certain way. With a pond level below grade there is simply no place for water to drain. Unless you add a sump pump and can move the water some place far away and down hill. But even then getting water out from under a liner with 4-10 tons of water pressing down on it is virtually impossible. Drain rock is going to be pressed into the mud, no problem. Then you'll have bigger problems because your pond will sink along with the rock.

This business about building the top of the structure (pond level) above grade is not something new. Swimming pools are built this way and so are home foundations for the very same reason.

Yeah shortly after writing that last post I read somewhere on here (probably one of your posts) about raising the pond up alittle bit. Seemed to make alot of sense and a good way to keep the ground water from pushing up, so that is what I will do. I will also scrap the whole weeping tile idea as that is not needed anymore. I do think I need to keep the gravel in the bottom of the pond though. Right now the bottom mud is about the same consistency as swamp mud and not firm at all. If I were to jump in right now I would probably sink 1 foot +. I need the gravel to be able to slope the bottom towards the bottom drain and also for somthing to concrete the bottom drain into.

Waterbug, are you concerned about the gravel base shifting down or just about the fooling around with the weeping tile?

 

[Waterbug]

Waterbug, are you concerned about the gravel base shifting down or just about the fooling around with the weeping tile?

A gravel base would sink I assume. I'm not there so really don't know. I'm not concerned because it isn't my pond. Whether you should be or not I don't know, I don't know you, or your design, or really anything beyond rocks in mud sink. It kind of depends how much rock you add. It's the gaps between the rocks that will fill with mud and cause the pond to sink.

A sloped bottom for a bottom drain is not a good idea. That concept is only something first time pond builders think is needed. Flat bottoms, with a slightly lower area around the drain, function better. Bottom drains require Tangential Pond Returns (TPRs) to move debris to the drain, sloped bottom does nothing. If you read how professionals build ponds you will see this. If you don't want to add TPRs I wouldn't bother with the drain at all.

When working on muddy bottoms I cut a piece of carpet the size of the bottom and toss that in. Then lay a couple 1'x1'x3/4" pieces of plywood down to stand on. Water sweeps thru the carpet and is easier to pump out. The more you walk around the more water comes up thru the carpet and the more solid the mud becomes. You can pull up one end of the carpet to dig more, but it's a huge pain.

An alternative is to change the pond design to a partly above ground formal type if you want the depth. I don't like digging mud by hand.

Bottom drain
For the bottom drain I'd install it above the liner instead of under the liner if the mud is completely too much of a pain. Try to dig a trench as best you can. This can be just digging half the pond down a bit deeper since you can't really dig a trench in mud. Lay the liner and then set the drain pipe on top and try and wiggle it down so the liner sinks under the pipe. That gives you some trench, probably not much. You can use short lengths of spare pipe and vibrate the pipe to see if that will sink it. An orbital sander is a good vibrator. So you get the pipe down as much as you can.

Then fill the bottom with concrete to the top of the pipe to get the final level. In this case I wouldn't use a manufactured drain. Instead use just the pipe and form the drain in the concrete.

https://www.gardenpondforum.com/gallery/image/2285-aboveliner/


Concreting a drain under the liner in mud really doesn't help you any. Drains are concreted in to keep them stable so the liner isn't pulled out of the clamp. Mud isn't stable so the concrete won't add stability.

 

[Waterbug]

For the drain on top of the liner you'd also need to build a cap. That's really easy. Let me know if you need directions.

 

[killerbren]

Update!

Alright, well the carpet and the plywood in the bottom are really good ideas. As it turns out the pond is starting to dry out a little and I was able to get some work done. I was able to build walls on the side to separate the pond from the gravel bog going around the edge, with the top of the board being 1/2 inch above waterline. The bottom of the pond is starting to firm up and i'm going to try and set the bottom drain in place tomorrow.

Sunday should be a big day. Im planning on taking out the sump pump and putting in the underlay and liner, a few rows of rock along the walls and see if I can get a couple feet of water in the pond to keep everything down.

Here is what the pond looks like today.

 

[Waterbug]

Picture 3 kind of freaked me out. The shadow looks like one from the opening of The Exorcist.

 

[killerbren]

[sub]Okay, concrete is in and the bottom drain is solid! I managed to put 220 lbs of concrete around that sucker, tomorrow I form the bottom of the pond, out comes the sump and in goes the liner.[/sub]

 

[addy1]

Great going!

 

[j.w]

You're getting there!

 

[killerbren]

Okay, had a good day today, managed to get the liner in place and some rock in the bottom.

Got the bottom done and level, put some plywood, then carpet down for a decent base.

Got the underlay in and secured, started to unravel the giant liner and get it ready.

Got the liner in and started to get it in the right place.

Rocks going in!

 

[j.w]

Now you're really looking like your making progress. Won't be long till the water goes in :banana:

 

[killerbren]

Ok guys and gals, I need your opinion. The rocks are up about 1/2 to 3/4 up the sides of the walls and I have about a foot of water in the bottom (that I added) but heres the problem. While ive been walking around the bottom Ive felt three or four gravel sized rocks just under the liner. Now I put a big carpet down and then underlay and I think the rocks got pulled in by accident when the liner went in, so I think they are between the underlay and the liner. looking at the rocks from the outside they look like they could do some damage eventually.

So my question is, do I drain down the water and uninstall the liner from the bottom drain to get the rocks or will that ruin my seal when I hook it back up? dont really see any other option at this point.

Otherwise things are going great, plumbing should be done today, if I get it done later I will take pics and show you guys. once the plumbing is done it shouldnt take long to get the rocks to the top and I will be flowing water!

 

[Waterbug]

EDPM is very tough. Muddy bottom, stones should sink some. One question you have to ask yourself....if I remove the rock, the water and part of the liner, what's to stop more stones from getting into the same position. Has to be your call.

I generally lay out the liner like in your pic and then fold it up so when I set it in the pond the center of the liner in laying in the center of the pond. Then unfold. Don't know if you did it that way but imo it makes it easier not to knock stuff into the hold than dragging the liner over the hole.