Pond Construction (Also see "Pond and Waterfall Pictures" to the left.)
When you have settled on a design and have drawn a plan for it, a couple of things to think about concerning construction. Build your pond just like a small swimming pool, with 3/8” rebar installed in a grid pattern 10” O.C. maximum, with no vinyl liner underneath (it’s a waste of time and money, and is going to get holes in it anyway). Contact “Dig Alert” or whatever they are called in your area to locate any underground utilities and their pipes and things before you start excavation. Do not forget to do this!
When excavating, create a shallow area inside the pond basin which amounts to a large shelf inside the pond, and build your waterfall here. In this way, the pond can never lose water because it is all contained inside the pond basin, even if the waterfall leaks.
Waterfall construction can involve artificial or real rocks and boulders, or a combination of the two. We offer artrificial rocks and boulders for sale and instructions on how to install them. If you choose real rocks, try to create as many small rock pools as possible that are laterally offset and stepping down the front and even sides of the falls, and finally into the main pond basin. Try to avoid building a "rock pile", with water shooting out from the top rock. I have seen many waterfalls built this way and they usually look very unappealing.
Create a "starter pool" with smaller rocks or boulders at the top of the falls that overflows into the next small rock basin down from it, and so on. The smaller the waterfall, the fewer cascading basins you will have. Typically the basins are an oval shape and will be somewhat smaller at the top (roughly 1' x 2', or 2' x 3') and increase in size slightly as they descend down the front of the falls.
After your pond is excavated, dig a trench for the intake pipe (2” minimum diameter), then refill trenches with clean fill that is free of any rocks to prevent pipe damage over time. Set a form for the pond edge perfectly level all around the perimeter except in the area of the waterfall. Use a contractor’s transit level to do the pond edge. This way when the pond is filled up completely, the concrete edges do not show and ground cover and other plants can grow over the pond edges, giving as natural a look as possible. If there is a waterfall on a hill that is flowing into the pond, then a flat but slightly sloping extension of the pond must be added to the area where the falls will be to catch all of the water and return it to the pond. The edges of this “catch basin” must be raised 6”-8” to keep runoff from getting in and pond water from splashing and running out.
Now you are ready to set your steel in a grid pattern. Steel may be set as close as 6” o.c. or as much as 12” o.c. Form steel tightly to the ground. Later, install dobies (small blocks of concrete with tie wire protruding out) under the steel grid in enough places to lift it off the ground. When you pour the concrete, the steel will be totally imbedded in it. Use no more than 40 grade 3/8” rebar, because it is strong and very easy to shape and bend for free-form ponds. The finished concrete should be at least 4” thick. Use loop ties and a tying tool, available at masonry suppliers, to tie the rebar together.
When pouring concrete for the pond, if it’s over one cubic yard, get a cement truck and concrete pump to do the job. Otherwise mix it by hand in a wheel barrow or two, or in a small mixer if you have one. You’d be amazed how many small ponds I have built with a couple of wheel barrows, shovels, mixing hoe, trowels, and just a few workers. After mixing the concrete by hand, lay out the mix as smoothly as possible with a metal float and apply two coats of Foundation Thoroseal. The best concrete mix to use if it works for your climate is a seven sack mix. You may want to consider shot-crete if it’s available in your area. This is pump-mix concrete shot out of a large hose under pressure; considerably more than with a regular concrete pump. The shot-crete allows concrete to be applied to higher verticle surfaces without dropping off. Gunnite is certainly another option for applying cement to the pond, and may be necessay where you have large amounts of vertical walls to apply cement to. Concerning the application of the concrete or gunnite: it is probably worth it to go ahead and pay extra and find quality finishers to trowel on the material professionally.
Some people need to know how well the water features hold up in cold weather, and the short answer is to investigate on your own how that issue is handled by masonry, pool, and concrete contractors in your area. Whatever applies to their finished structures is going to apply to these water features that we’re doing. Whatever a home owner must do to winterize their swimming pools in cold climates will have to be duplicated for a waterfall.
Electrical Circuits for Water Features
While you are working on the different phases of the pond, you should be working with the electrical part of the project, too. This should be done by licensed, qualified personnel only, and with the proper building permit. As far as your power source for your project, an existing exterior receptacle is the easiest, most convenient point of attachment. An interior receptacle will also work: simply drill a hole the size of a threaded pipe adaptor out the back of the junction box from the inside of the house, through the exterior wall covering, and attach the conduit to the J-box . Even better is taking the circuit from the main panel box of the house. If you need 220 service for the pump, you must have room in the panel for a new breaker and then create an access to the panel for the new circuit.
When you run a circuit out to the site of the water feature from your power source, whether above or below ground, use 3/4” conduit minimum. Make sure the receptacle for the pump ends up within the reach of the pump’s power cord, but still hidden from view, behind the waterfall or plants. To shield the pump’s power cord from rain or sprinklers, install a waterproof cover by Intermatic. Using 3/4” or 1” conduit, and stranded, 12 or 10 gauge wire makes wire pulling much easier, especially when there are numerous turns in the conduit and long runs to pull through. Pull an extra hot wire or two for future lighting or auxillary circuits while you’re at it; it will make things easier for you. Underground conduit must be schedule 40 pvc plastic pipe installed to the depth specified for your area in the code (usually 18” minimum). Above ground should be galvinized EMT conduit and fittings or per applicable code. If the pump is running continuously, no timer is required; you may want install a switch only. Otherwise a basic Intermatic mechanical timer is all you need for the simplest and most reliable operation.
The water feature should be properly grounded for maximum safety. In addition to the normal grounding to the main panel via metal conduit or grounding wire inside plastic conduit, a solid copper wire, # 8 minimum must lead from a clamp on the rebar grid in the concrete pond shell to the exterior ground terminal on the pump itself. Check local codes and confer with your building inspector to confirm this point. All of the previous information on the electrical installations is not meant to replace careful study of, and compliance with your local area’s electrical codes. The information is a general guide pertaining to water features only and is not represented by me as being all-inclusive. I disclaim any responsibility for any problems you might have in this regard.
Pond Equipment Installation
One of our specialties is installing pond pumps and biological filters for fish ponds and waterfalls. We can install equipment for new or existing water features. We also offer for sale to the consumer and do-it-your-selfer an excellent line of pond pumps, pond filters and ultraviolet clarifying units. (Click the appropriate bar to the left to view our products.)
Oftentimes, pond builders will install the right kind of filter, but one that is too small to handle the "biological load" of the pond, mainly fish waste, algae blooms in the water column, and debris that is blown in from trees and other landscaping.
A very common filtering and circulating system (and I use the term loosely in this case) is a submersible pump with some sort of intake screen or even a filter on the intake, which pumps the pond water to a filter somewhere outside the pond, and then to a waterfall and back into the pond. These set-ups are invariably a royal pain in the rear! They do not cycle the water through the filter often enough during the day, the intake in the submersible pump is constantly clogged, and ususally the filter is easily clogged up and offers too little surface area to propagate enough nitrifying bacteria to keep the pond water clean and clear.To keep this contraption going, the pond owner either has to spend a lot of precious time taking the submersible pump out of the pond to clean it, and taking apart the pond filter to clean it; or paying a pond maintenance company $ 80 to $ 120 monthly (or more) to do all of that for them.
If this sounds like your situation, CALL US! We can save you a lot of time and aggravation so that you can enjoy your pond! We guarantee our work, have numerous references, are a licensed general contractor, and have twelve years experience exclusively in design and construction of fish ponds and waterfalls.
We prefer Aqua Ultraviolet biological pond filters for their performance and ease of use. When installing these filters, we recommend using one size up as far as the rated capacity is concerned if it is too close to the water volume of the pond. For example, on a 2,000 gallon pond we would use an Ultima 4000 instead of an Ultima 2000. Keep in mind that to "step up" like this you must follow the manufacturer's recommendations for the flow rate of your circulating pump, which, using our example, would be a pump that delivers at least 4,000 gallons an hour to the filter. Two speed pumps work well with these filters because the high speed setting of the pump creates enough pressure to backwash the filters properly. Remember to follow the manufacturer's recommendations closely regarding the backwashing procedure.
Water features should be designed for energy efficiency and ease of maintenance. Once you have decided on a location for the water feature, think about the best place for the equipment, too. This does require some serious attention because the best balance between how it will look and sound, and how well it all works together is not always apparent at first.
The main components of the water circulation system utilizing a centrifugal pump are: main drain (intakes), pond skimmer, pump and strainer (leaf trap), filter, u.v. sterilizer, return line. If there is only one main pond intake, it should have an anti-vortex cover to protect people, and fish, if any are planned, from the strong pull of water through it. It is better and safer, however, to have at least two main intakes in the bottom of the pond. That way if one becomes blocked or obstructed, water continues to flow through the other one. If the pump is below the waterline, install a gate (ball valve) just before the pump strainer to hold back the pond water while the strainer basket is being emptied and cleaned. The pump strainer catches any debris pulled in through the main intake before it reaches the impellar.
The pump and other equipment can be below water level if desired, creating a condition known as flooded suction. This means that instead of having a high amperage pump to create suction to pull water through the main intake in the pond, your pump will already be flooded with water inside the impellar. This way you can get by with a lower amperage pump, and that means less noise and power consumption.One design to enable the pond pump to have flooded suction is to have the walls of the pond raised above ground eight or more inches. Another design is building a below ground level (and water level) pump house, but it must be made rain proof and flood proof. As a precaution, install a 3” or 4” drain and line inside leading away from the pump house.
What to do if the pond edge is at ground level, and the pump is above that level, as is often the case? We create an artificial water level in our intake line by installing a swing check valve a few inches below the water level of the pond. Ideally, the valve on a 2” intake line would be a 2 1/2” or 3” “true union” swing check that is installed “downhill” at a 45 degree angle. The body of a true union swing check valve is replaceable without cutting the main intake line and glueing in a new valve. It should be positioned in an access box underground in front of the pump.
To increase system efficiency, cut down on flow resistance (friction loss) when water is flowing through the suction and return lines by using at least 2" pipe, and as short runs of pipe as possible and as few 90 degree fittings as possible. One 90 degree fitting is equal to about 10 feet of the same size pipe in friction loss. One example for reducing friction loss is instead of 90 degree fittings, use two 45 degree fittings, or 90 degree “long sweeps”, which are available in schedule 40 PVC pipe.
The size of pump you use is also contingent on whether or not you have plants and fish. If you don’t, and it is strictly ornamental in nature, size the pump to achieve the effect you want with your waterfall. In this case power usage may not be as much because the system is only running four to six hours a day. The pump will need to run long enough each day to cycle the water through the filter a number of times. When I say cycle I mean the water is completely recirculated one time. Anyway, the only other time you need the pump running is to run your waterfall. The pond pump must run continuously if it is maintaining a fish pond. Either way, you want to use the smallest pump you can to do the job, or at least a high quality, energy efficient pump. When choosing pumps, or any other equipment for that matter, please decide what your requirements are and then obtain the specifications you need from the equipement manufacturer or supplier. Although there are several ways of putting together these systems, they all work on the same basic principal.
The next major component in the water circulation system is the filter. This is another area which is again dependant on whether you have living things in your water feature. If you don’t, then use a cartridge filter. The size of this will depend on the size of the pond, where your equipement is and how well you can hide it all. With natural water features you must hide or disguise your equipement. For water features with plants and fish, (after testing many different fiters and methods over twelve years), Aqua Ultraviolet bio-filters are the only ones I install, period. Always install a good quality ball valve in line between the pump and filter. That way you can slow down the flow of water to the filter if necessary to let it work more effectively. The ball valve can also help control excessive splashing out of the boundaries of your waterfall therefore cutting down on water loss.
There are a few more things we need to add to our water circulating “loop” after the filter. One is a check valve, which keeps the water in the return lines from draining out when the pump goes off due to a timer shutoff or if shut off manually. The check valve reduces the work load a little for the pump every time and also prevents a loud gurgling noise from occuring every time the pump is turned on and is pushing air and water up through the return line, especially on the taller waterfalls.
After the filter and check valve comes the ultraviolet sterilizer. The u.v. sterilizer is a must for live ponds; optional but recommended even for water features without plants and fish. Depending on what size unit you use, it can greatly reduce or eliminate the need for chemicals such as chlorine or bromine in ornamental ponds. U.V.’s kill free-floating algae spores, parasites, and bacteria harmful to fish and people.