Liner Ponds and Pondless Waterfalls - An Asset or Liability?

The first "pondless" waterfall was designed and built in Fallbrook, California in the early 1980's, long before the advent of rubber or PVC pond liners. However, that particular design was referred to as a "childproof waterfall" with its descriptive name lending a better definition of its function and purpose.

This design was the result of solving the enormous liability issues related to small children drowning in bodies of standing water such as swimming pools and ponds. The client wanted a waterfall in his front yard; however, there was no possibility for a pond due to the topography and space restrictions. In addition, building codes restricted pond depths to 18 inches, unless all of the code requirements were satisfied, such as bordering the body of water with a 6 foot fence, a special gate requirement, and door alarms, to name just a few.

The client also stressed to me the importance of low maintenance. A pond, regardless of its depth, becomes a catch basin for blowing leaves and debris. Other maintenance factors included algae growth from the water's exposure to sunlight, and evaporation resulting from larger surface area of the water.

By capturing the waterfall water in a subterranean cistern, all of the previously mentioned code requirements and maintenance issues are resolved by eliminating the cause: a pond.

The pleasant results are the beneficial sound and sight of a waterfall minus the liabilities or high cost of maintenance. Since the water will spill through rock placed on top of galvanized steel grating that covers the collection basin (cistern), the collected water stays cooler. And in the absence of sunlight, there is no algae problem. By placing a fine galvanized hardware cloth between the covering of loose rocks and the galvanized grating, leaves and small debris are prevented from ending up in the collection basin and can be removed easily by hand.

This "child-proof" or pondless waterfall was constructed of 3500 psi concrete (with stealth fiber added) and reinforced with #3 rebar placed 8 inches on center. This type of construction will survive earthquakes and last for decades. Reinforced concrete shells that are properly sealed with a concrete sealer such as Thoroseal will not only permanently waterproof the concrete, it will prevent alkali and phosphorous from leaching into the water, making it permanently safe for aquatic life.

Most modern-day "pondless" waterfalls are constructed with rubber or PVC liner. Pond liner advocates tout the assets of liners as being faster and cheaper to build; they even claim that liners last longer than concrete. Liner ponds and waterfalls may be faster to build, but they are not necessarily cheaper or stronger. Case in point:

In August, 2007 a previous client of mine in Rancho Santa Fe, California informed me that they were buying a 15,000 square foot home on three acres. They asked me to check out an existing waterfall and pond on the property. The previous owners informed them that they had paid a pond liner company $276,000 to construct it, only to have it leak within a few months. The loss of water was so great that they had to shut it down. The liner guy came out to inspect it, pointing out a rodent burrow mound among the surrounding rocks and boulders. He stated that it was gophers, ground squirrels or rats, or possibly all three, that had chewed a hole in the liner. He quickly added that the liner was warranted against factory defects only, but not from acts of God, man, beast, or any creeping thing.

As if that was not bad enough, a second liner company was called out and paid $75,000 to repair the leaks, which they attempted to do by plastering around the base of every rock in the waterfall. UGLY does not properly describe it. Talk about a tropical paradise turning into a tropical nightmare! Within two months it was leaking worse than before.

I was commissioned to crane out all of the two- to five-ton boulders and remove all the remaining smaller boulders and rock with a Bobcat, then rip out all of the liner and replace it with 3500 psi reinforced Shotcrete.

The waterfall's width was doubled and 40 feet was added to its height, doubling the width of the pond. The original 2-hp pump was replaced with five 3-hp high-efficiency pumps; the original 12 lights were replaced with 65 accent lights. All of this was completed for $40,000 less than the original cost of the pond and waterfall. (Note: The total amount paid for their waterfall in original construction costs and replacement costs was $586,000. Over a half a million dollars! So is a liner really cheaper than reinforced concrete?) It took the original liner guy twelve days to complete the project; it took us just five weeks.

So much for cheaper and longer-lasting... What about liability or asset? Every rock and boulder in the entire waterfall and pond was secured in place with mortar, unlike the liner waterfalls where rocks and boulders were placed on the liner loosely and could easily shift, move or topple over when walked on, creating an extreme liability.

In light of the prior facts, comparing liner construction with reinforced concrete, liner ponds and waterfalls can end up costing twice as much when considering replacement costs and repairs. Most "pondless waterfall" advocates stress three major selling points on the use of pond liners for "pondless waterfalls" and koi ponds:

1. They are cheaper to build.

2. They last longer than concrete.

3. They require less maintenance. The truth... there is more profit to be made by the pond liner guys. They are in and out in one to two days! Will they come back and fix the problems that will surely arise, is the big question.

Liner ponds and "pondless waterfalls" are they an asset or liability? Before you invest your hard-earned money, be sure you know the answer.