Vanishing edge pools are an optical illusion where the edge of the pool seems to disappear in the horizon. The pools were made popular in 1971 by the James Bond film "Diamonds are Forever."

If a client wants the visual impact of a vanishing edge pool as a design element in the landscape, but doesn't care about actually swimming in it, a better option might be a vanishing edge pond.

That was the recommendation of Scott Cohen to his San Fernando Valley client who wanted the illusion of a water feature blending into the view of the valley below the property, but not the expense of building and maintaining a pool.

"The client had a magnificent view, but didn't want a large swimming pool, just a small hydrotherapy spa," said Cohen, a landscape garden artisan and owner of The Green Scene, which provides outdoor design consultations for clients throughout Southern California. While Cohen had designed many vanishing edge (or infinity) pools for clients, he had never created a vanishing edge pond.

"A vanishing edge pool would have been very expensive to build on that lot," said Cohen. The cost for the infinity look on the steep landscape would have added $200,000 over and above the standard cost of a regular pool, bringing the price tag to $350,000.

Cohen thought the pond solution was a good alternative that could be built for under $20,000. “I actually had never heard of a vanishing edge pond before I created this one for my client,” said Cohen.

Vanishing Edge Mechanics
Many of the same mechanical principals for an infinity pool apply to a vanishing edge pond, said Cohen. One similarity is the creation of a weir, or wall, that creates the illusion of a vanishing edge.

The weir's spillway is slightly lower than the rest of the water feature so gravity pulls the water down into a collection basin, where it can then be recirculated. These simple water mechanics become more complex when constructing a pool, noted Cohen. People jumping into or just swimming in the pool create waves that make this simple design more challenging, adding to the cost. "Calculating the hydraulics for a vanishing edge pond is easier than a pool; you don't have to take into account bather surcharge," he said playfully.

However, the similarities between the two end with the water mechanics. Building a pond is a fraction of the cost because of the lack of steel sides, plaster, tiles, pool pumps and heaters. "When building a pool you are creating an environment where you don't want anything to grow." said Cohen. In a pond, you want an environment where things do grow, and even thrive.

"With the pond, you are creating an opportunity to plant a new garden; it is a showcase to install water lilies and flowering, naturalistic plants." In essence, a vanishing edge pond is just like creating an ordinary pond, with the addition of the spillover weir. "With the pond, you are creating an opportunity to plant a new garden; it is a showcase to install water lilies and flowering naturalistic plants.""A vanishing edge pond is just a few thousand dollars more than a standard pond. Anyone who has experience building a pond can pull this together," said Cohen. For his client, Cohen went a step further by constructing a bridge between the pond and the hydrotherapy spa so that the bodies of water looked connected, but remained separate. The water spillover gave the effect (and sounds) of a waterfall, and a smaller pond below the larger pond acted as a catch basin. Biological pumps recirculated the water back up into the larger pond. The cost for the total project, including the spa, pond, bridge and other landscaping elements, came to $160,000.

Pond construction A simple masonry wall was built; to keep the edge level, workers set a course of cinder blocks on concrete footing. This was then capped with stone. "The weir has to be perfectly level," noted Cohen. A polishing tool used for granite countertops was used to make the stone that capped the weir perfectly smooth. "The smoother the spillway, the better visual effect of water; it almost looks like glass," he said. When selecting a recirculating pump, Cohen says that landscape designers should account for overflow in the event of heavy rains. "You don't want to send water down a slope to a neighboring property." The vanishing edge pond had a 4-foot drop to the outside edge, which went into a collection basin 2.5 feet deep and 2.5 feet wide.

The bridge was created out of cast concrete and stamped to resemble wood. Under the bridge, an 8-foot-wide spillway further creates the illusion that the pond and hydrotherapy spa are from the same body of water. The larger pond has two biological filters and two pumps: one pump circulates the upper pond, and the other creates the infinity effect and returns water from the lower pond. Cohen used all Aquascape (www.aquascapeinc.com ) supplies for the pond portion of the project.

No fish were harmed ...
While creating the vanishing edge pond was a straightforward project, Cohen faced his major problem once the project was completed. "The little goldfish we placed in the pond would slip over the side and end up in the basin," he said. They quickly realized that only larger fish, such as koi, are suited for living in a vanishing edge pond. "We did save all the little goldfish," said Cohen with a chuckle, and added that workers installed netting that remained in place until the fish got too large to slip over the edge. You must also consider the depth of the vanishing edge pond, or any pond, when adding fish. Too shallow in a hot climate and fish will not survive in the warm water, but too deep and you may be violating state regulations.

In California, for example, a pond deeper than 18 inches is classified as a "pool", and the property must be fenced in or enclosed for safety reasons.

The Effect
Since the water's reflective quality mirrors the horizon beyond the pond, it is important, Cohen said, that what is reflected in the pond is beautiful and worth reflecting. "You don't want the pond to be under a power line," he said. The pond doesn't have to be on a cliff overlooking a dramatic valley scape to have a magical quality, said Cohen. The reflection can consist of an attractive tree or shrubbery, or even a fire element, such as a fire pit. Landscape designers should note what exactly will be reflected when positioning the vanishing edge pond. Cohen recommends that the spillover face east or west. "That way you can get sunrises or sunsets over the pond," he said. The end result of a well-designed, well-positioned vanishing edge pond can be a stunning design element to a landscape, said Cohen. "It is a very versatile option. You can put a rectangular one in a formal garden or create medallion shapes for an Eastern-influenced landscape," said Cohen. "You are only limited by your creativity." Cohen has created two vanishing edge ponds for clients. After one of the ponds was featured on HGTV, his business-with 12 construction crews and 55 workers on staff-has received several inquiries to build more. "The vanishing edge pond differentiates us from others in the industry," said Cohen. "It is a niche, but it is a terrific opportunity to capture a greater market share."

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