July 15, 2010
How to transform a watery money pit into a wildlife oasis
Maybe the swimming pool came with your house. Or perhaps you installed a pool as a hedge against summer scorchers. But then the novelty wore off, and you’re stuck with a watery money pit that demands more time, money, and effort than you bargained for. The occasional swim doesn’t seem worth the guilt you feel when you have to scoop out a critter who accidentally drowned; the pristine blue water doesn’t look as inviting when you think of all the chemicals you’ve broadcasted over the water.
Homeowners who are fed up with their swimming pools often resort to covering them year-round or filling them with concrete, but there is another option. By converting your pool into a wildlife pond, you can build a more natural landscape and provide animals in your neck of the woods (or city) a much-needed wetland habitat. And the time you once devoted to pool upkeep can be spent relaxing in your backyard haven and watching the wildlife you nourish.
From Baby Steps to the Deep End
Before starting any work, think about the best design for your space. Create a small-scale drawing of the pond, taking into consideration your pool’s dimensions, the surrounding landscape, potential planting zones, native plant options, and the safety of pets, wildlife, and small children. Include details such as contours, waterfalls, streams, sandy beaches, the filtration system, and wildlife escape routes such as ledges, shallows, rocks, logs, aquatic plants, and other pond furniture. When deciding on the right depth for your pond, keep in mind that a 3- to 4-foot-deep pond will allow you to wade in the water for service and cleaning.
Getting to the Bottom of It
If you decide to use your pool’s existing liner—which is only recommended if the liner is concrete, not plastic or metal—consult with a professional about power cleaning any residual chemicals that could be toxic to aquatic animals. In colder regions, concrete-lined ponds may crack with temperature changes, endangering wild inhabitants when the water drains out. To avoid challenges presented by your pool’s existing liner, you can opt for a flexible synthetic material specifically made for ponds that can be shaped to the underlying design.
Asking the Experts
Converted swimming pools make for relatively large ponds that require a filtration system to keep up with algae and biological debris; consult an expert to determine the best strategy. Also, contact your local native plant nursery or university cooperative extension to ask about plant choices native to your region, and join a local pond society for helpful additional advice.
Diving in with Nature
If you want the best of both worlds—swimming and wildlife watching—consider converting your pool into a swimming pond with the help of a knowledgeable professional. Rather than using chemicals, these ponds incorporate natural biological filtration systems that are beautiful and eco-friendly.
Taking the Plunge
After you’ve done your research, you’ll have a good idea of what a pool-to-pond transformation requires. Here are some basic steps you’re likely to take.
1. Using twine or rope, mark the planned locations for the filtration system, pipes, pump, and other structures, such as a waterfall, a stream, or planting beds.
2. Begin shaping your pond according to your plans. You can give the pond a contoured bottom by adding varying levels of soil. Sprinkle the soil with water and walk on it over the next several days to pack it down. A more effective method of compacting loose soil is to use a vibrating plate compactor, which can be rented from most equipment rental stores. Once the soil has settled, you may need to add more to keep the depth at the desired level.
Alternatively, you can create a contoured bottom using sandbags that are half-filled with sand or soil. First add soil directly to the pool until you reach the maximum desired depth. For example, if the pool is 6 feet deep and you want the water to be 4 feet at its deepest, fill the pool with 2 feet of soil. Pack it down using a vibrating plate compactor or the manual method described above, and add more soil as needed. Next, stack the sandbags on their sides in rows that decrease in height from the edge of the pool to the center, leaving some space between the rows. Fill in this space with soil and sprinkle water over the area for several days to help it settle, adding soil as needed to keep it level with the sandbags.
3. Place a pond liner over the entire area and contour it to the bottom, sides, and ledges. Cut the liner well past the edge of the pond and secure it with flat, heavy rocks, leaving open areas along the top for inflow and outflow pipes, filtration, and planting beds. Cover any visible liner with soil.
4. Place river rock along the pool’s bottom for biological filtration, and add various-sized boulders to create a more natural look and prevent sun damage to the liner. Use smooth-edged materials to avoid puncturing the liner.
5. Fill your new pond with water to within a few inches of the top (lower if you live in an area prone to heavy rains and flooding). Allow the water to warm up and the chlorine to dissipate for at least 24 hours before adding vegetation.
6. Place planters at recommended levels at or under the water’s surface. Floating plants and vegetation along the edges attract a variety of wildlife. Rocks that peek above the water’s surface can be used by animals as escape routes or for basking in the sun, as can shallow ledges along the sides. Logs and other pond furniture provide additional sunning and hiding places for wildlife.
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