Whether you have a sprawling lawn or a cozy patio, building a water garden can create an enchanting addition to any outdoor space. The sight of flowing water and the sound of cascading falls provide a relaxing atmosphere and a sense of peace that many homeowners enjoy. Water features are often complemented with a variety of plants to create a natural oasis, a beautiful focal point for the landscaping, and even provide a habitat for aquatic life.
Whether you want a small garden fountain or a large waterfall pond, this brief guide will take you through the basic steps to create your own water feature, from planning and design to maintenance tips.
Planning and Design
Consider the size and shape of your location, the amount of sunlight it receives, and any
landscaping features. Keep in mind that larger ponds require more maintenance but offer
greater biodiversity. Choose a spot that receives at least six hours of sunlight per day and is located away from trees to minimize debris falling into the water. Keep the site near an outdoor ground fault circuit interrupter (GFCI) outlet and plan the most direct line possible between the house and the pond for the pump’s power cord.
Decide on the style of your water garden, whether it's a formal pond with geometric shapes or a naturalistic pond with irregular edges and native plants. There are unlimited possibilities for the size and shape of your pond or water garden, but a capacity of at least 15 to 25 gallons is practical.
DIY’ers may want to choose a kit, because the products are already included for a hassle-free assembly, sparing you several trips to the store. Even if you don’t buy a kit, checking out what’s in the kits can often be helpful when matching parts. Remember to check for parts compatibility when buying different brands for the same project.
For small water features, consider a container garden, which is essentially a large pot of water that contains aquatic plants. Container gardens are a good way to construct a water garden before committing to a larger, permanent pond.
Preformed rigid pond shells include shelves to hold aquatic plants. The rigid pond liners are available in a variety of sizes and are usually constructed of UV-resistant
recycled plastic. Shown here is a preformed liner from MacCourt Products, Inc.
Start with a large ceramic pot, a galvanized tub, a wood barrel lined with plastic, or a preformed rigid pond shell which includes shelves to hold aquatic plants. The rigid pond liners are available in a variety of sizes and are usually constructed of UV-resistant recycled plastic.
Larger, more ambitious water features can be constructed on a slope or hillside to take advantage of the downhill water flow over excavated shelves, which creates a waterfall effect.
Excavation
Once you've finalized your design, it's time to start digging. Mark the perimeter of your water garden using spray paint or a rope. Avoid underground pipes, cables, sewer lines, septic fields, etc. Call 811 if in doubt to have the utilities marked. Most small ponds can be dug out with common hand tools—pickaxes, shovels, spades, etc. However, your water feature can be as large as you want, and big projects might require construction machinery.
The excavation depth can vary but will need to be at least 18 inches for aquatic plants and fish to thrive. In some communities, 18 inches is the legal depth limit, meaning that if it’s any deeper, some building codes might consider it a swimming pool and require a permit to build it.
You’ll have a significant amount of excavated dirt you can use to build up the sides or shoring of the waterfall. If ground elevation allows, incorporate ledges or overhangs along the path of water to create drop points that will make interesting waterfalls throughout the feature. Construct rock walls or shelves around the perimeter of the pond to accommodate different types of plants.
Pondmaster Super-Flex is a flexible polyethylene-based pond liner that is half the weight of
traditional EPDM liners.
Pondmaster liners combine the strength of polyethylene liners with exceptional flexibility to conform to the contours and shelves of the pond excavation. This fish-safe liner is ideal for koi ponds, aquatic habitats, water gardens, waterfalls, fountains and streams.
Installation
Flexible pond liners require underlayment or a layer of sand to protect the liner from punctures. If using a 3-in. sand bed, you’ll need to add 3 inches to the excavation depth. (A preformed pond container may not require underlayment but should be installed so its bottom rests on flattened and compacted earth.)
Install flexible pond liners so there are no wrinkles or folds which could cause leaks.
Pond liners are available made of polyvinyl chloride (PVC) or ethylene propylene diene monomer (EPDM rubber). These are available in several different sizes, from 7-by-10 to
20-by-25 feet, to accommodate small or large projects. Lap the edges 8 to 10 inches over the edges of the pond, leaving a little extra in case you find a low spot where a leak could occur. Backfill under the rest of the liner and then cover it with soil, mulch, rocks, or plants. Trim back any exposed liner.
Flexible pond liners generally require underlayment or a layer of sand to protect the liner from punctures.
For in-ground ponds, you can use a wheelbarrow to add topsoil to help create the berm around the back and edges. The berm will help blend the water feature with the rest of your yard. Construct a retaining wall to hold large berms in place.
Filtration and Circulation
Proper filtration and circulation are essential for maintaining water quality and preventing algae growth. Install a pump to gently circulate the water, which helps oxygenate the water and prevents stagnation. Pump capacities vary according to the volume of the water in your pond. Pumps will require hose long enough to recycle the water as needed throughout the feature.
Add a biological filter to remove excess nutrients and harmful bacteria from the
water, promoting a healthy ecosystem.
Consider incorporating a UV clarifier to control algae blooms by sterilizing algae
cells and preventing them from reproducing.
Your pond parts will also need to be high efficiency. The pump should turn over the pond’s total gallons of water once every two hours. Research and compare before choosing the parts that are right for your project.
Install the pond filtration pump according to the manufacturer’s instructions, then fill
the pond with fresh water.
The water feature’s pump should have enough capacity to turn over the pond’s total gallons of water once every two hours.
Landscaping and Planting
Add the finishing touches to your water garden with landscaping elements and aquatic plants. To blend a naturalistic water feature with the surrounding, landscape pros often
recommend incorporating rocks and plants native to the area.
Use larger rocks, such as flat flagstones or irregular boulders, as foundational elements to define the ledges and the outside perimeter. Work in smaller stones as transitional elements. Mixing varying shape and sizes of rock can give a look of depth and variation.
Plug in the pump and watch the way the water falls over the rocks. Place small rocks on the waterfall stone and move them around, observing the changes in the sound and the splashing. Tweak the path of water until you achieve the desired flow effect.
Pro tip: Apply Expanding Landscaping Foam to seal gaps between the stones, the biological filter, and the liner to divert the water over the stones (instead of beneath or between them).
Choose a variety of aquatic plants, including submerged, floating, and marginal plants, to decorate your water feature and provide habitat for fish and insects. Place taller plants at the back and shorter plants at the front to create visual depth. Rocks, gravel, or driftwood around the the pond can protect the edges and complete a naturalistic look.
Pro tip: If using underwater lights, wrap two or three feet of cord around the base of the
light and tuck that into the rocks. This makes it easier to retrieve the light from the water to change bulbs.
Building a water garden is a rewarding way to enhance the landscape and create
a tranquil retreat in your backyard. Follow these steps and incorporate your own creative touches to have your new water feature flowing nicely for years of low-maintenance enjoyment.
For a natural look, define the edges using rocks native to the area.
Side Note 1 How To Choose a Pump
Does your pump need to send water cascading over a waterfall or run a small fountain? Application is important when selecting a pump. Fountains or “spitters” typically require a smaller pump, but waterfalls require more calculation to determine the required size. UV Clarifiers or pressure filters typically come with a manufacturer’s recommended pump size for optimal use. Check the product manual for recommended pump size but understand that head pressure will also be factor.
Water should circulate through the filter at least once every two hours, which means a 1,000-gallon pond needs a pump with a capacity of at least 500 gallons per hour. For fish habitats, professionals recommend doubling the pump capacity to ensure that the water remains clean.
Pump size is not only related to pond size. Head pressure and the desired flow rate will also determine selection. Head pressure refers to the friction created when pumping water uphill or over long distances. Flow rate determines how much water moves through the feature over a given time.
Measuring Head Pressure: Head pressure is calculated and represented in terms of feet. It’s
a combination of the length of tubing and the vertical distance from the water surface to the
top of the waterfall. Every vertical foot of distance the return pump moves water equates to 1 foot of head pressure.
The effects of friction on head pressure are more difficult to calculate, but roughly every 10 feet of pipe (horizontal and vertical) through which water is traveling adds 1 foot of head pressure. (Every 90-degree bend also adds 1 foot of head pressure, which is one reason why flexible pipe is preferred.) Therefore, a water feature that is 3 feet tall with 16 feet of tubing would have 5 feet of head pressure.
Note that pipe diameter is important when calculating head pressure. For minimum head
pressure, use the largest diameter pipe that fits the pump is best.
Measuring Flow Rate: The average amount of water moving over a waterfall is 1,500 GPH for
every 1 foot of width. Therefore, a waterfall that is 2 feet wide would need a 3,000 GPH pump. To achieve a heavier flow, calculate your desired flow rate using 2,000 GPH per foot.
Pumps are sold with head pressure and flow ratings listed among the product specifications,
and you will need to choose a pump that offers the capacity required for your project.
Side Note 2
Water Garden Maintenance
To keep your water garden healthy and thriving, regular maintenance is key. Here are some essential tasks:
1. Use a skimmer or net to remove debris such as leaves, twigs, and algae from the water surface.
2. Trim and prune aquatic plants to prevent overgrowth, reduce insect infestation, and maintain a balanced ecosystem.
3. Regularly monitor water quality properties such as pH, ammonia, and nitrate levels, making any necessary adjustments.
4. Maintain your filtration system, including cleaning or replacing filter media and checking pump operation.
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