Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Bought a house with a pond, now what?

Hi! First time poster, looking for advice.

I recently bought a house with a small pond. Picture attached; I'm letting it drain while figuring out what repairs it needs.

* Eyeballing, it's about 30' diameter
* 2-3 feet deep when full
* Kept full year round by pumping from a well
* Probably been here like this for 50 years
* In California... it's hot, it never freezes, and it barely rains

It's right next to the house and as far as I can tell it's unlined. Not only does this require fairly continuous pumping in the summer, but water saturated ground has been causing the foundation to sink.

I've fixed the foundation and probably won't have further trouble, but I'd also like to do something to slow the water intrusion and reduce the pump rate. I'm thinking more along the lines of "reduce the leakage" rather than "make it watertight", but I'm not really sure what's possible or even a good idea.

My goal for the pond is just to have something pretty to look at, that grows reeds and frogs and dragonflies. No interest in fish and I want it to be as low maintenance as possible. I don't mind pumping water but I don't want to manage filters or chemistry or anything like that.

Should I try to mix some bentonite into the bottom? Or just put some overlapping plastic liner layers without worrying about sealing them too much? If I do seal it too well, do I need to worry about making a miniature Great Salt Lake with the summer evaporation?

Any advice is welcome (except "fill it in" )

Thanks in advance!

Welcome to Pond Boss!

Your goals for a pond right beside your house sound very nice.

I definitely would not like having a LEAKY pond right beside the house.

If it was my project, I would certainly consider installing a pond liner to get a 100% effective seal.

I believe quality pond liners currently run about $1/sq. ft. (If you buy it locally and avoid the shipping charge.) That would only be $900 for a 30'x30' pond.

If you want water plants, then I would create a few level shelves in the pond before placing the liner. You can then place dirt-filled black plastic pots on the shelves that do NOT stick up above your water elevation. You can then plant lilies, reeds, etc. in your pots and have nearly complete control over their location and spreading.

If you want lots of edge plants, then create two rims with your liner near the circumference of your pond. The narrow basin between the two rims can be filled with soil to support your plants. The inner rim should be just below your normal water elevation so the plants have water that can exchange with the main pond - but the soil cannot.

What I suggest above will certainly involve a fair bit of labor. However, it can all be performed by 1-2 able bodied adults for a pond and liner that small. There are also crews for hire that do those installations. (If you hire a crew, then you can also increase the depth since they will have earthmoving equipment. Or you can easily run a mini-excavator yourself. They are easy and safe to operate on level ground, even for a new operator.)

If you do NOT like the liner, or it is above your budget for the pond, then I would definitely try to perform a seal job on the existing pond.

Sealing jobs always have a chance for failure. However, a 3' deep pond has very little hydrostatic pressure trying to push the water out through the leak paths. If your conditions are moderately favorable, then it should not be that difficult to seal.

If you want to go that route, my best advice to you would be to contact our best leak expert (TJ). He can recommend if physical product additions might work, or if you need full-scale construction equipment repairs.

Here is a link to his profile: TJ Profile

You can contact him via Private Message through the forum, or through his email which is listed in the profile.

He may not respond rapidly, since he is probably catching up on family time during this part of the year. However, he graciously volunteers to give free advice either in the thread (for public viewing) or in a phone consultation.

He also sells a product called SeekLeak, which is frequently more efficient and/or cost effective than bentonite in sealing several types of leaks.

Good luck on your pond project!

First things first, carefully excavate a hole somewhere in the basin to get through the accumulated muck and check for a liner that already exists. You don’t want to add new holes so be careful. A small pond like that is likely to have a liner that has failed due to age, and hidden due to thick muck. What that will tell you is if the soil has any chance of sealing or not, and how much work it will be to restore or improve it as the old liner will need removal.

IMHO a pond this size and smaller requires a liner unless you have a very high water table or natural water source that never quits. A nice heavy duty felt protection layer and thick UV protected liner is a worthwhile investment, especially if you are filling in a dry climate area. It may pay for itself over time in water cost differences. Even in our normally wet climate I must top off our lined pond a few times a year due to evaporation. Ours is 20x18 before lining with rocks and plants.

If you decide to line it, and have some elevation to your advantage, install a bottom drain. I wish I had as cleaning it out is a chore without one. What is nice with a liner is it does allow a partial drain and clean out periodically. Natural liners are not nearly as easy.

There are a lot of resources for designing and building lined garden ponds. I find the hobby incredibly rewarding, as I did my project myself with the help of a neighbor’s excavator.

Best of luck and please keep us posted on what you choose to do!

I would do like liquidsquid said and check carefully for a liner. If no liner, I'd excavate to get all the existing "muck" out of the pond basin, and go 12" deeper. Get a 1 piece liner, install per mfg. recommendations and cover it with 12" of dirt that came from the last layer you removed. NOT the muck that you removed.

Pieces of liner that aren't glued together (sealed) won't work and you will be losing water. With that so close to the house, it is probably contributing to the foundation problem you had.

As for no fish. I'd rethink that and toss in some mosquito fish or fathead minnows to dine on any mosquito larvae. Mosquito fish will do a better job of that and they may be available free from the county vector control agency.

The dirt is needed to protect the liner from UV rays, and the dirt will be the growing medium for your plants. Frogs need it too - they burrow down and hibernate during the winter, no matter how short it is.

Thinking to the future, "making it watertight" will probably save you money in the long run looking at current utility prices vs. "reducing the leakage".

Stick, welcome to Pond Boss.

You have been provided good experienced advice. Believe it and Heed it. There are Pros at installing liners. Get at least 2 quotes and references from them of past work. Go visit those projects. Ask questions of the owner. People with ponds ALWAYS like showing off their pond and talking about it. Don't always take the cheapest quote. Will there be a leakage clause in the installation contract?