What type of foundation for pond/stream?

[FJ and G]

I understand that concrete, linings and preforms all have pros and cons. I want to design a pond about 4X16 ft, an uphill pond about 4x6, connected by a stream that's about 20 feet long on an 8% slope in my backyard. Which foundation for the pond/stream would you use? My soil is mostly impervious clay mixed with shale and metamorphic rock. Live in N. Virginia near Manassas.

I'm new at this.

(BTW, I've already got a large collection of toy trains (3-rail) and plan to use these in the garden, using Atlas track that can stand up to the weather.)

[Anonymous]

The latest pond put on my property is about 15' x 20'. It has a stream of about 30' on a natural slope that flows from the "waterfall" box to a small pond. The small pond, 3' x 4', that then overflows into the large one.

After many months of hand digging and sculpting plant shelves, I laid about 2" of stone dust (same material used for ballast). On top of the stone dust, I put a specially made synthetic woven material for pond underlayment. It is designed to prevent damage from tree roots and sharp rocks and is very strong.

On top of the synthetic pond liner, I placed a EPDM pond liner.

(I am leaving on a business trip for a few days. When I get hack I will get the name of the synthetic material and who I bought it from.)

[Capt Bob Johnson]

I'm over by the Delaware Beaches and have my entire layout raised 28" on a sand fill.

We used an underlay of something almost like tyvek, but more water permeable, then a liner of 45 mil rubber to make a 22foot X 40foot X 3foot Pond. Worked great, but make sides fairly steep. Make sure shelf layer around sides is backsloped to keep plants placed on shelf from sliding into central part of pond. Bottom of pond slopes toward 1 end for ease of pumping/cleaning. Don't forget big capacity for overflow, summer squalls can fill to overflow real quick. 3inch overflow isn't enough on my pond, should have put 2 of them in!

I used both terra-cotta flue liners and cinder block chimney pieces to make islands to hold plants. just tied old carpet to bottoms to protect pond liner. The flue liners give fish place to get into shade and to hide from birds.

Remember, herons are a wading bird. if sides too steep for wading and pond too deep you won't have birds dining on your live tuna (Koi - goldfish - catfish, etc.)!

Whatever you decide to use, go for it!

[Anonymous]

This is avery complex matter, I would go to university and study civil engineering before i did anything.

ian

[Anonymous]

You have 2 choices for building a foundation for your pond and stream.

1. Build a foundation / structure that will NOT flex under any condition. This would be a traditional steel reinforced concrete foundation. Very expensive, very messy to install.

2. Build a flexible foundation that can move with the surrounding soils. This would be an engineered fill compacted in place. This is what the RR's do for the tracks, and how streets are built.

I'd go with #2.

Excavate at least 8", or preferably below frost line and bring in roadbase or crushed rock. You'll need to compact it with a "jumping jack". To protect the pond and stream liners you'll need to cover the sharp stuff with sand. Make sure you design a little "slop" in the height of the pond sides to make sure the liner runs well above the outlet to your stream in case something moves.

I'd then line the inside of the stream with suitable rock to make a babbling stream, hiding AND protecting the liner. Ditto with the pond liner, or you could use a thin layer of sand with plants & such.

Don't forget running the electrical and plumbing before you make everything look pretty.

A guy I used to work with did this a few years ago. Used shotcrete and spent a small fortune, before he ended up moving 2 years later.

Mark in Utah

[FJ and G]

Mark,

What you say makes sense. However, what about punctures and UV rays? The reinforced concrete sound good but it too has problems such as possible cracking and lime that could pollute the water.

I've got a beagle that might run through the water and the thought of her claws penetrating the lining isn't too pleasant.

I'm still in a quandry. Wi***here were a perfect material easy to put down, low cost, lifetime durability, impervious to cracks and punctures, etc.

[ttrigg]

F J and G

I'm just finishing with my pond/waterfall/stream, and have a very valuable lesson (MISTAKE) to pass on.



As you can see from the photo I used a rubber liner, which needs to be covered by stone for UV protection. The "underlayment" I used was almost a half inch thick and did not need the layer of sand as required by some, and since my sides were very steep, no way for sand to stay put.

My lesson learned
Provide for water drainage UNDER the pond. The "dirt" in my backyard is "compacted white clay" and when the contractors built the house they compacted the clay in layers, so water does NOT drain away. (Had to import soil to grow grass, and compost by the truckload for the wife's rose beds.) My neighbors water line ruptured and water got under my pond and pushed in the sides as the water under the pond developed greater pressure until I "over filled" the pond. Its been over a month of dry weather and the water is still there.

Under your pond, dig in a drainage pipe to remove any water from under your pond!!!!

[FJ and G]

thanks Tom,

I too have clay and that could pose a problem. With concrete, OTOH, the liner would be much more durable and solid.

[Anonymous]

They make liners that are UV resistant and quite durable. As long as it's properly protected, it should work just fine. As long as your beagle doesn't try to dig through it, it should be fine. I'm pretty sure they also make patching / splicing supplies, so you can either patch holes or fuse mutliple sheets together.

Adding supplimental drainage under the pond, withing the gravel bed would be a good idea if you have very poor drainage.

Mark in Utah

[ttrigg]

FJ and G

Since my most recent experience with the side walls (liner only) of my pond bulging out and breaking the mortar around the rocks, I now remember seeing swimming pools "float" up out of the ground. That was over 40 years ago, but if concrete could float that long ago it still could.

I still say no matter what kind of pond you ultimately build, put in some drainage UNDER the pond.

[Anonymous]

FJ & G
In my earlier post, I said I would get some more information to you when I returned from a business trip. The material I was referring to was called 'Liner Protection Fabric' sold by a company called Resource Conservation Technology, Inc. The web sight is http://www.pondtechnology.com/

When I purchased from them five years ago, they had a comprehensive catalog with good instructions. They also included small sample pieces of the protection fabric as well as the liner.

I still have some of the fabric in my garage. E-mail me your address if you are interested and I will send you a sample.

I am also attaching a photograph of the pond that was built by me with this material.



***

[FJ and G]

***,

Thanks, I'm browsing through their website and will consider them.