This client wished for a waterfall and pond, however, they were concerned about the safety of their two toddlers, plus a baby on its way. There also was an issue of noise from busy freeway traffic above and 20 yards beyond the backyard retaining wall. The sound-frequency of freeway noise is "white noise" and so is the sounds from a waterfall. Close your eyes and listen to the sound of a freeway, then envision a roaring waterfall!
So by creating a large volume of water falling from a great distance, a large volume of "white noise" can be generated to mask the freeway sounds.
The first step is to pour a substantial footing that attaches to the footing of the existing wall by drilling and inserting rebar. Next, a rebar grid is attached to the wall and the ponds structural frame. Then the entire rebar structure [8" to 10" on center] is covered with concrete [applied under high pressure- Shotcrete] Cost of concrete and application: $1,700
After allowing a couple of days to cure the concrete shell is then covered with rock and boulders that are mortared in place with aqua media mortar mix. so anyone, especially small children, can climb on the rocks without them moving, resulting in possible serious injury. Unlike concrete construction, rocks in liner pond and waterfall construction will move and shift, even on their own. After a few months, the liner is exposed in the falls and around the pond. In addition, rubber liners can develop leaks from gnawing rodents such as rats, mice, gophers, chipmunks, moles, ground squirrels, including roots from trees and even plants like philodendrons.
While building the concrete pond-less [convertible] waterfall, design liberties can be taken, such as altering the length, width or shape of the feature. With a "liner pond-less waterfall", the parameters have already been set by the manufacturer of the kit.
With a Pond-less (convertible) concept, the rocks can be removed from the pond area and filled with water after the toddlers are grown or in the event you decide to sell your home to someone who prefers to have a pond.
The collection basin in the middle of the pond area serves to collect the water falling from the waterfall. The basin is covered with galvanized planking to support the rocks covering it. Fine galvanized hardware cloth is placed over planks to prevent debris from entering the basin. The basin needs to be able to hold three times the volume of water being circulated. Two 8" anti-vortex drains are installed on the bottom of the basin for pumping and circulating the water.
Since you cannot see the water level, without removing the rocks and galvanized grates, an electronic float control valve mounted in the basin will automatically keep it full. Caution: Avoid mechanical type floats, they are know to corrode, stick or jamb and then you will no longer have a pond-less waterfall... and may end up creating an unwanted pond in your neighbors yard. Unlike the mechanical floats the electronic AquaFill type water level float controls never stick, jam rust or corrode, and will virtually last for 15 to 20 years. Now there is no need to access the basin, since the pump is outside and draws water from the anti-vortex drains on the bottom.
Concrete waterfalls are stationary, natural looking, permanent, lifetime expectancy, cheaper to build, cheaper to operate, easier to clean and maintain, and safer than a liner constructed waterfall and pond. Plus a centrifugal pump lasts longer than a submersible and is 60% more energy efficient with a longer warranty.
On the average, concrete construction cost only 20% more than liner ponds and lasts for decades.
Need more ideas, simply Google Search "Design a Pond" there are over 1 million search results of videos, reasonably priced training courses, articles and photos- Go ahead, Do it yourself... it is easier than you might think!