By Anita B. Stone, Photographs by S. Tullock – Do you know the basics of farm pond design? If you’re ready to tap into a small backyard pond system on your homesteading land, put nature to work and achieve a sustainable ecosystem while creating a beautiful focal point in the landscape, simply use the following seven steps to plan your water feature.
Step 1: Considerations For Successful Farm Pond Design
There are several things to consider when adding a water feature to the landscape. The first step to a successful farm pond design is to decide what type of pond you desire. Putting your basic farm pond design on paper is a must, so you can see exactly what you are going to construct. Consider the types of aquatic life you want in the pond, whether it is a home for goldfish, a haven for koi, or a combination of plant and aquatic life.
Water circulation is essential and the use of an aeration pump allows you to keep more fish. Liners and shells or stones come in a variety of materials and shapes. Check the pre-fabricated hard shells sold at home improvement centers. A flexible liner can be made to your specifications. No matter what features you choose you have to decide on your approximate cost and overall budget.
The next consideration in creating your farm pond design is to select the proper location. Most ponds are enjoyed when they are installed close to your home, so select an area where you can see the pond. For a small ornamental pond, position it where runoff from rain will not flow into the pond because you may be troubled with chemicals, fertilizers and debris that find its way into the water. Avoid placing a pond too close to trees because falling leaves and limbs will need to be removed from the pond.
Before construction, make sure you check with your county for the proper pond construction permits and with your homeowner’s insurance company for liability and protection from any mishaps.
Step 2: Materials
For any good farm pond design to be successful, you will need a top-notch pond liner that will adapt to any shape or size that you decide to make. Pond liners are sold by the square foot and can be joined to form larger liners. Since liners are priced by the square foot, purchase the exact size you require to save hundreds of dollars.
A flexible butyl rubber liner will last 30 years or more and will not become damaged from the ultra-violet rays and is far less likely to suffer from frost. It is slightly harder to install because it is harder to bend and fold, unlike PVC.
Most people choose PVC because it’s cheaper and will last for about 15 years. PVC is strong and won’t be damaged by frost, but more care is needed to ensure it doesn’t rip or tear.
Pre-formed pond inserts are ideal because they are extremely durable and less susceptible to tears and punctures. An asymmetrical liner is easier to install and needs to be raised off the ground. Once it is high enough, push stakes into the ground to try and map out the shape and contours of the pre-formed liner.
These inserts are very strong, but be sure to support the bottom and all the sides. Do not press down hard when installing them, in case there are sharp objects or protruding stones.
Step 3: Determine the Size and Planting Area
A good farm pond design for a recreational pond should be about 10–15′ deep. A fishpond should have a water depth of at least 15 feet. For a koi pond, make sure you have no less than 1,000 gallons of water in volume. To avoid oxygen depletion and stress on the fish, it is better to maintain a depth of 18–20′ or more.
Planting the area surrounding the pond with shrubs should be done as soon after construction as possible. Shrubs can help with erosion, privacy screening, space definition and climate control. Surface-looming plants such as water lilies require four to six hours of direct sun. Water lilies with surface leaves provide 60 percent shade for fish. Choose plants that optimize natural bacteria to provide the fish with healthy living conditions.
Step 4: Building
There are basically four main ways to construct your farm pond design. Using a flexible liner, a preformed shell, creating your own concrete shape, or simply digging out the desired shape of the pond using tractor bucket attachments and compressing the soil to make it water tight. You will need to add any plumbing prior to installing the liner. Know where any utilities are before digging, to avoid any disasters. When ready to build, mark the area using spray paint, a hose or chalk. You can also place the liner upside down in the desired location and mark around the edge with string or garden hose. Fish are thought to prefer oval or circular shaped pond areas as opposed to square corners.
Once the pond is outlined according to your original farm pond design, remove the liner and excavate to the deepest part of the pond. Dig a hole vertically about 14 inches deep, the size and shape of the pond. Allow about four inches extra width and depth, and keep the dirt close by to use later. It is important to form the sides of the hole level all the way around or the water level won’t be level once the pond is completed. The edge of the pond should have a slight rise to keep out rain run-off.
Reinforce the sides of the pond with 28-gauge roofing flashing. Push PVC stakes six inches into the ground to hold the flashing in place. Smooth the bottom and sides of the pond by clipping all roots and removing rocks, and then cover the bottom and sides with roofing felt.
Once the hole is dug, there is a little plumbing to be done. It is suggested to use 1-1/2″ PVC pipe for ponds up to 1,500 gallons, then graduate to two-inch pipe for ponds over 1,500 gallons. Three- and four-inch pipe should be considered for ponds over 2,500 gallons. When installing PVC, use PVC glue to attach the pipe to the bottom of the pump, allowing debris to be removed. Most of the plumbing will be hidden under the liner and buried in trenches.
If you have an extra $1,700 to install a bead filter, it will trap lots of bacteria and may be added to the system, depending on the size of the pond. You can install an ultraviolet lamp to sterilize free-forming algae so that the water does not turn green. The bead filter will take out the dirt and make the water healthy but the water will not be clear without a UV unit. The UV is a PVC plastic cylinder with two openings so that water can pass from one end to the other. The water passes over a sleeve inside the cylinder where a lamp is encased that emits ultraviolet rays. The UV does not go under water and is most effectively installed after the bead filter. An electrician can assist with the procedure.
Once the extras are installed, place the liner inside the pond. Make sure there will be at least 6″ of extra space around the edges. Once the liner is level, begin to fill with water slowly, and backfill any gaps between the liner and the ground with sand. Keep the bottom and sides smooth by pulling out wrinkles and folding in corners and curves as it fills up. Let the water settle for at least one week. One of the best ways to minimize damage to the liner is to make sure the material is barely visible above the water and that all sides are level.
You can decorate the pond by edging it with stones or bricks; they should overhang the edge by one or two inches. You can also create a six-inch-high shelf around the perimeter of the pond where rocks and boulders hide the liner. Make sure the waterline comes up over the top of this shelf, but not over the top of the liner.
Pull the excess liner over the top of the first layer of stones. Secure them in place with more stones, and keep adding stones until the liner is invisible. Rake the excess dirt back toward the pond to cover any excess liner and secure the rocks in place.
Digging Plant “Shelves”
If keeping plants as part of your farm pond design, dig a shelf around the perimeter of the pond about one foot deep and one or more feet wide—wide enough for the pots. Repeat for all shelves. In small ponds, plant shelves may become an invitation for predators to “climb the steps” and feast on the fish. To counteract this situation, you can place plants along the side of the pond at varying depths without the need for shelves.
Dig the remainder of the pond with a slight slope to the end, opposite the waterfall if one is included in the design.
Pond waterfalls and streams included in your farm pond design can be excavated once an external filter or tank is positioned. This can be placed to spill directly into the pond. A pump is required to run a filter, a fountain or a waterfall in the pond.
If a skimmer is being used to remove debris from the surface of the pond, dig a ditch to the pond pump. Skimmers should be buried beside the pond. If you are using a submersible pump in the skimmer, then the ditch will be from the skimmer to the external pond filter.
Most ponds will benefit from the use of a biological filter. If you keep koi and several goldfish it is recommended to install a biological filter.
It is easier to create and maintain a biological balance in a larger farm pond design. A small pond limits the number of fish and plants. Ponds built in cold areas may need more depth to keep the pond from freezing solid. A finished pond or water garden will probably be smaller than you visualize, so after you lay out your original farm pond design, measure the maximum length and width. Add the depth twice to these measurements plus an extra two feet for overlap, and this will give you the correct pond liner size.
Step 5: Stocking the Pond
Once the pond is filled with water, wait three or four days before adding fish. A good rule of thumb is to purchase only healthy fish from a reputable nursery. They should have erect fins, demonstrate good activity, and a good appetite. How many fish can you stock? Use this as a guide: one inch of fish for every cubic foot of pond surface. You can increase the number of fish if you have a good pond pump and filtration system.
To avoid stress, allow the fish to sit in place inside the contained bag at the edge of the pond for about 20 minutes. Add some of the pond water to their bag to level the pH, and then let the bag sit another 15 minutes. Tip the bag and let the fish swim into the pond.
Never overfeed the fish or the food will pollute your water. If you spot tiny fish, remove them as they may be eaten and keep them in quarantine in another area until they’re larger. During hot spells, the water temperature may get too hot and the oxygen level too low. To increase the level of oxygen, pump the water through a waterfall or fountain, as the droplets of water will contain oxygen when returned to the pond.
Provide places for the fish to hide in the pond by inserting a series of plastic piping into the water. This will enable the fish to hide from birds, cats, and other dangers. An ideal pond will require about five hours of sunlight a day. Sunlight keeps oxygenating plants working, which keeps the water from turning stagnant. Try to cover half the surface with water lilies to achieve some shade across the water.
Step 6: Care and Maintenance
Farm pond maintenance is essential, but simple to do. Check the water quality of your pond on a monthly basis, because water quality will determine the health of the fish and plants. High ammonia levels stress the fish, making them susceptible to disease. A mistake is to think that clear water equals healthy water.
The pH of the water measures acidity, with a range from 0 to 14. If the pH is below 7, the water is acidic, above 7, it is alkaline and equal to 7 it is neutral. The carbon dioxide levels come from fish metabolism, plant respiration, pollution and organic acids in the water. Because impurities also lower the pH level, it is advisable not to use city tap water. Try to stick with a pH level between 6.8 and 9.0. These levels are ideal for both goldfish and koi.
Nitrates are highly toxic to fish. Control nitrates by changing water and filtration. Ammonia is converted into nitrate and is an important part of the nitrogen cycle. Algae in the water consume nitrates as well as plants. To encourage the plants to send out roots and consume waterborne nitrates and phosphates, limit the amount of soil you use. The amount of food you give your fish also influences the concentration of nitrates present. Only feed an amount of food that is eaten within a couple of minutes. Never overstock your pond, as this increases nitrates and the possibility of ill fish.
If alkalinity is less than 50 parts per million, then wide pH swings are common and a filter problem is imminent.
To remove any chlorine, add dechlorinator to the pond and aquatic plants as soon as possible to serve as nutrients.
Remove any dead and dying growth, seed heads and leaves, clearing the pond of all rotting vegetation. Some effective plants recommended are Water Hyacinth, Parrot’s Feather and Bacopa.
Step 7: Seasonal Plant and Pond Requirements
During spring, feed fish only with pellets and only enough that they can consume in five minutes. Decaying vegetation and plant growth may make the water black and cloudy, especially in a small pond. Remove any decaying material and perform a partial water change. Trickle in water from a hose, and allow the pond to overflow.
Next, examine your pond plants. Baskets can be raised and the plants divided and replanted. Replace weak plants with new plants. Examine the pond liner for any signs of cracks or rips. Examine everything for wear including electrical cables, and replace if necessary. Clean filters and test underwater lighting/submerged UV filters. Clean the pump filter and run the pump for an hour to ensure that it is fully functional.
Cover pond-side plants that are not hardy with straw, or bring them inside for the winter. Fit or check any pond netting that you have placed over the pond. In autumn the pond may freeze and seal off the water surface, preventing oxygen from reaching the unfrozen water. This stops the toxic gasses from escaping and the ice can cause damage when it expands. If the pond has sloping sides, the ice will be forced upwards. If it is particularly cold, then you can use a pond heater that will heat a tiny fraction of the surface, enough to allow oxygen to reach the surface. Never break the ice with a heavy blow, as this sends shockwaves through the water that can stun or kill the fish. The best method is to place hot water in a metal can that will gradually melt a small part of the surface. You can also drain some water under the ice, as this will act as a form of insulation and still keep some oxygen in touch with the water.
There is relatively little to do for winter maintenance, besides servicing any pond components. The biggest worry for small ponds in cold areas is the danger of prolonged spells of ice. Simply allow oxygen to reach the surface.
If you wish to achieve an ecosystem pond, line the area with rock and gravel, and then combine fish, plants and beneficial bacteria to create a water garden that practically takes care of itself.
Plant tall plants like reeds, cattails, and cannas in clusters in the background of the water garden. Then, snuggle medium height plants close to the taller ones. You can choose water willow, blue pickerel, and bog arum. Add copperleaf plants in front of the cluster.
To create a stable system, use biological and mechanical filtration, bacteria, fish, plants and plenty of rocks and pebbles. Make sure there are no visible pumps, plumbing or liner material. Simply empty a skimmer basket of twigs and leaves. This type of water pond depends on active bacteria. Though a 6′ x 4′ pond can achieve a natural balance, larger ponds such as 8′ x 11′, for example, achieve the same balance quicker and more effectively, establishing a more stable ecosystem.
Whatever type of pond you build, maintenance is of primary importance. With proper care, your completed farm pond design will offer years of enjoyment, peace, and beauty.
Originally published in the March/April 2010 issue of Countryside & Small Stock Journal and regularly vetted for accuracy.