We want to dig a pond, use clay as liner, do we need a pump? Our pond will be approx 20 x 20 and 3 to 4 foot deep. We don't have a spring near the location so do we need a water source other than the water hose? We will have ducks and maybe a few fish. I don't want it to stink. Thanks

-- Lesa in Va (Lemaradd@aol.com), March 22, 2002

Answers

How big is your watershed? Look uphill!

-- Terri (hooperterri@prodigy.net), March 22, 2002.

if u dont have a spring 2 fill it build it so run off water keeps it filled like in a ditch or gully

-- Grizz workin near D.C. (southerneagle@yahoo.com), March 22, 2002.

You'll have to haul in the clay, of course, unless the pond will have a natural clay bottom when you dig it. Rather than haul and spread clay, it might be much easier to line the bottom with visquine, which is pretty cheap at home improvement stores. Then put a layer of dirt on top of that.

Another possibility is sodium bentonite, which expands greatly when wet and is used to seal large ponds. I think it's available in bags. Just put those words in the Google search engine and you'll find a source for it or ask around some farm supply stores in your area.

Where you put the pond is a major consideration. If you put it on a high spot on your land, you'll have to top off the water with a hose or depend on rainfall to replenish loss through evaporation.

If you just dam up a swale, or depression at the bottom of a natural watershed it'll collect water pretty fast and you shouldn't have to use the hose too often if the bottom is sealed well. Rainfall from all around the watershed will collect in your pond.

But that definitely will create the need for a spillway, which must be a foot or more below the top of the dam so that excess water can run out and away without overflowing the pond or going over and washing away the dam. And if you have fish you'll probably need some kind of little fence across the spillway to keep them in during overflows. But without a spillway, the water will simply overflow all the banks and the fish will scatter everywhere.

You can line the edges of the pond with good sized rocks for a nice appearance and to help hold the banks from silting in. You could also pile up some rocks at one end and use a submersible pump to create a waterfall.

Various water plants in the pond can help create a balance in the water chemistry, but you might want to consider some kind of filtration system. Without one, small ponds can quickly turn stagnant. The waterfall would help circulate and aerate the water and might be enough.

Beyond that, I suggest you scour the web with some keywords related to ponds in the Google search engine. Don't settle for just the first few pages of results -- keep going through most or all of the page links. Eventually, you'll find tons of links which will provide good advice.

-- Hank in Oklahoma (hbaker@ipa.net), March 22, 2002.

BTW: If you use plants in your pond put them in pots rather than plant them in the bottom. And keep any dead parts of them trimmed off and out of the pond. Over a period of time dead plant matter can create havoc in a small water system.

It would also be a good idea to establish some thick-rooted plants or grass around the banks to hold the soil. And a few clumps of papyrus make beautiful, natural accents when strategically planted around the bank.

-- Hank in Oklahoma (hbaker@ipa.net), March 22, 2002.

Ducks and fish will constantly make deposits in the water. If you don't have a constant flow of water through the pond either natural or manmade the "nutrient" buildup will eventually cause problems.

One solution is to use a biological filter and pump the pond water through it on a continuous basis to clean and aerate the water. You can buy one readymade (expensive) or build one youself. I built one for a pond about the size of yours, it was a bit deeper, using a 70 gal Rubbermaid stock tank.

The tank was screened by shrubs so the filter wasn't visible. The hose from the submersible pump was hidden and the 3" return line from the filter ran underground to a small waterfall built into a rock wall on the side of the pond.

-- Darren (df1@infi.net), March 22, 2002.

Another BTW:

Water chemistry is more of an issue in small ponds than in large ones. Basically, fish need oxygen and plants need carbon monoxide. Plants produce oxygen from their intake of carbon monoxide, so that helps balance things out a bit.

But fish produce waste and that creates ammonia, which in higher concentrations is lethal for fish. The solution to this problem is to allow beneficial bacteria to become established in the pond. One type of this bacteria converts the ammonia to nitrIte, which is still harmfull to fish, and another type converts the nitrIte to nitrAte, which in reasonable concentrations is harmless to fish. This is known as the Nitrification Cycle and it must exist in a pond for it to be healthy for fish.

Aquarium websites especially offer lots of good information on this cycle. Here are a couple of good ones to start with:

http://faq.thekrib.com/begin-cycling.html

http://www.tomgriffin.com/aquamag/cycle2.html

-- Hank in Oklahoma (hbaker@ipa.net), March 22, 2002.

That's carbon DIoxide, not MONoxide. Dioxide is what is produced as waste by living creatures, monoxide is the poison from incomplete combustion, as in exhaust gases.

That's a fairly small shallow pond. If you have ducks in it, it will fill up with duck manure. You won't need to worry about the fish or underwater plants, though - there won't be any. Swimming in a pool of their own liquid manure is a good way for ducks to get infected with salmonella, too.

Even if you keep your own birds out of the pond, shallow as you propose it to be I'd think there's some danger fish-eating birds would come in, but at least the pond would stay pretty - until it dried up. Shallow as it is, you've got a big surface area for the volume - this would only be seasonal water here, but I don't know about your climate.

Honestly, I think unless your pond was MUCH bigger the ducks and you would be better off with them using a small wading pool and you changing the water frequently.

-- Don Armstrong (from Australia) (darmst@yahoo.com.au), March 22, 2002.

Yup, Don's right about the DIoxide. I thought that was wrong when I wrote it. Been a while since I fooled around with water plants -- just got my DIs and MONs mixed up.

He's right about the ducks, too. I used to keep runner ducks in my yard in a city and all they had was a six-foot diameter kiddie's playpool and it suited them fine.

There's nothing wrong with the planned depth of your pool and you might even get away with a couple of ducks, but any more than that would probably be a surefire recipe for eventual disaster.

Ducks are not only major poopers but they're constantly puddling and digging with their bills. That habit, coupled with the fact that they're constantly traipsing in and out of the pond, will tax the pond's banks severely.

-- Hank in Oklahoma (hbaker@ipa.net), March 22, 2002.

As for the depth of the pond, a 20 x 20-foot pond four feet deep will hold almost 12,000 gallons of water. Unless the pond leaks it's not going to dry up. But you might have to keep the water level up with occasional additions from a faucet during the dry season.

Water is only oxygenated by exposure to air and that means on the surface. The higher the water surface to water depth ratio the better the water's oxygenated.

And fish-eating birds? Highly unlikely. I've known many people inland and along the coasts of Florida with small ponds full of Koi. Never heard of one losing a fish to a bird -- and there are plenty of fish-eating birds in Florida.

-- Hank in Oklahoma (hbaker@ipa.net), March 22, 2002.

Two more points. If you're using well water to fill the pond you won't have a problem. If you're using city water treated with chlorine forget about the fish living.

If you want fish depending on where you live, I might go a bit deeper with the pond. If the pond freezes over in the winter the fish could die from lack of oxygen depending on how many fish you have.

You can use an aquarium bubbler to keep one small area ice free and maintain an opening for oxygen exchange. Breaking the ice by hitting it in the winter can harm the fish in a shallow pond.

What you want is doable. It'll just take some thought and effort to prevent it from becoming a toxic mess.

-- Darren (df1@infi.net), March 22, 2002.

Lesa, Gets confusing ,don't it? With what you describe a pump is called for to aerate the water. Building ponds is part of our business, the biggest project we worked on was a 50'x150', 8ft. deep with a 4 tier, 7ft. wide waterfall. Most of out work is limited to small ornamental ponds in landscapes. I hope I can give you a couple of good answers, but the duck factor goes beyond my experience. You'll want a big pump for this project if you want it to have a positive effect. Something that is going to move at least a couple thousand gallons per hour. Keep in mind that depending on the height of head (the height of the discharge above the pump) and the distance between the pump and the discharge along with the diameter of the discharge line will all effect pump efficiency. Generally you're going to get 50-70% of what the pump is rated for. This can vary greatly depending on how it's all put together. Yes you can use hose water to fill and maintain the pond level. If you want fish just wait a few days for the chlorine to dissipate, sunlight will help it along. I believe a biofilter would be a nightmare to maintain under the conditions you describe. Biofilters generally are used in small shallow ponds ( about 2' deep) to primarily help maintain water clarity. I posted some advice to a previous question about ponds that might also be useful. Like I said before, this situation is a little out of my area. I would definately check with your county extention office for additional information, it's the duck factor. Here's a web site to also check out, I use their system and products and you may get some good ideas, it's www.aquascapedesigns.com, There's some helpful information there. Good luck.

-- JJ Grandits (JJGBDF@aol.com), March 23, 2002.

Its all in the balance. Some plants will help to take up the nitrogen in the fish and duck waste. They will absorb CO2 and will emit Oxygen when they are growing. During the winter die-off they will demand oxygen for their decompostition, thus taking it from the fish.

The manure from the ducks will provide for frequent algae blooms. This can be good for fingerlings but I doubt if you want too much of it because it will get stinky in mid summer. Tricky business, getting a balanced eco system.

-- john (natlivent@pcpros.net), March 23, 2002.