Creating A No-Fuss Pond

Figure A

Landscape designer Scott Soden of Artscapes designed this no-fuss pond for the backyard of homeowner Patty Giuntoli, who doesn't want to spend every weekend cleaning the pond. The project site is a 20- by 15-foot backyard with a flagstone patio under construction (figure A). The pond and waterfall are constructed of flat lava rocks for a natural look and enhanced by lush aquatic plants in and around the pond. Dry-stacked stone retaining walls enclose new planting beds and help to define the pond's curving shape.

Soden chose a filtering system that combines a biological filter with a mechanical filter, including a skimmer bag similar to those used in swimming pools. This system requires only a couple of minutes of maintenance each week.

At $1,100, the filtering system is the most costly element of this project, but homeowners can save a lot of money by building the pond themselves. A professional would charge about $5,000 for the pond and waterfall, but do-it-yourselfers can buy the materials for only $1,900 (excluding the cost of plants). This project is rated a 4 on a difficulty scale of 1 (easy) to 5 (difficult) and can be completed in three weekends with friends helping with the digging and heavy lifting.

Figure B

Step One: Shaping the Pond

Because of the elevation of the site, the crew builds a retaining wall using Napa field stones. Your site may not require a retaining wall, depending on the elevation of your yard. The retaining wall is built simply by stacking the stones (figure B).

Use landscapers' spray paint to mark out an irregular, curving pond shape, roughly 11 by 6 feet. Also mark out a parallel line, about 15 inches inside the outline. The space between the two lines will become a shelf for holding pond plants.

Dig out the shelf area to about four inches deep, maintaining the 15-inch width . Then excavate the pool of the pond to about two feet deep. Attach string lines running the length and width of the pond, and check the level in all directions.

Figure C

Carve out a 4-inch-deep basin just above the main pool, toward the waterfall area , as an interior level to create a cascading effect. Beyond it, carve out a space for the biofilter and waterfall (for this project, a 21-inch gap between the two retaining walls). Also dig out a 16-inch-deep hole near the other end of the pond to hold the skimmer box. Finally, dig out a few shallow plant pockets in the pond floor for setting aquatic plants in later. Figure C shows the excavated pond shape.

Figure D

Step Two: Setting in the Skimmer System

The skimmer box minimizes maintenance because leaves and other debris that fall on the pond surface get sucked into a net bag. Every week or two, simply pull out the bag, empty it, and put it back in the skimmer box. This system allows you to site your pond underneath a tree if you want. The skimmer box, pump, and biofilter (figure D) are sold in a kit for about $1,100 at pond supply stores.

Set the skimmer box into the hole at the end of the pond, with the drainage hole facing out toward the pond. Make sure it's level and secure.

Figure E

Glue a 1-1/2-inch tube extension onto the pump and top it with an elbow attachment (figure E). The attachment hooks up to a hose later to recirculate the water from the skimmer to the top of the waterfall. Set the entire assembly into the skimmer box and feed the electrical cord out over the top of the box.

Step Three: Preparing for the Waterfall

Set a few cinderblocks into the waterfall space for added height to intensify the waterfall's cascading effect. Fill the cinderblocks with dirt and hammer long pins through the dirt to hold the blocks in place.

Figure F

Glue the waterline from the pond kit to the back of the biofilter shell, making sure it fits tightly. The biofilter shell (figure F) is a plastic housing that also forms the waterfall basin. Set the shell securely onto the cinderblocks . Run the waterline along a shallow trench, outside the pond, to the skimmer box. Glue the waterline to the elbow attachment that is connected to the pump in the skimmer box. This completes the water recirculation system.

Figure G

Step Four: Setting the Stone

Before laying the pond liner, cover the pond area, extending over the pond shelf , with landscape fabric and tuck it into pleats to conform to the shape of the pond. Cover the fabric with a heavy-duty (45-mil-thick) pond liner, available at pond supply stores for about 50 cents per square foot. Drape the liner over the waterfall biofilter shell, too. Use caution, because even a small tear can result in a leak. Figure G shows the liner in place.

Use flat stones, such as lava rocks, to line the pond walls. Set the stones along the inner walls of the pond and work your way up. Set the stones on edge, best side facing out, and dry-stack them so they fit together securely like puzzle pieces. When you reach the ledge, lay stones flat to cover the pond shelf. To build the face of the waterfall, choose some of the largest and most attractive stones, and glue them to the liner using silicone caulking. Fill any gaps with small rocks or pebbles.

Figure H

Glue the liner to the front of the biofilter shell and attach a plastic lip (which comes with the kit) to create a spillway. Choose a thick piece of pre-cut flagstone and glue it in place so that it overhangs the plastic lip and completes the waterfall (figure H). Continue stacking more lava rocks around the waterfall to hide the liner.

Place some upright aquatic plants into the planting pockets on the pond floor, and secure them by placing cobblestones around the pots. Cover the rest of the floor with a combination of pebbles and cobblestones for a natural look.

Step Five: Installing the Filters

The biofilters consist of media materials on which good bacteria live and eliminate the bad waste products in pond water, such as nitrogen and ammonia. The simple filters have no moving parts or chemicals and are easy to install and maintain. They need to be rinsed out only once a year.

In the biofilter shell at the top of the waterfall, place three pieces of PVC piping, cut to span the bottom of the shell, to elevate the filter pads off the bottom. Then place three filter pads on top of the PVC for triple filtration. Add a small bag of cobblestones to weight down the pads and keep them from floating around in the shell.

Place another filter pad in the top of the skimmer box and then insert the skimmer net. Fill the pond with water and turn on the pump to test the system.

Planting: A Woodland Waterfall

The trick to planting around a pond is to use plants that are naturally found around a stream. Soden chose thick textural ferns, grasses, and mosses to enhance the pond and waterfall. He placed pots of aquatic plants into the plant pockets on the pond floor before filling it with water, and tucked moisture-loving plants and grasses in the nooks between stones. His planting plan includes:

• Umbrella plant (Cyperus alternifolius), Zone 11
• Japanese maple (Acer palmatum 'Sango-Kaku'), Zones 6-8
• Tasmanian tree fern (Dicksonia antartica), Zones 9-10