Building a pondless waterfall could be done by a contractor or as a do-it-yourself project. After the project is designed, the area marked on the ground, and the rocks, gravel and hardware are purchased, the building of the pondless waterfall may commence.
Digging the Catch Basin
Dig a hole where the catch basin will be at the bottom end of the waterfall. It should be deep enough so that the submersible water pump will not jut out over the top of the pit after it is installed. It should be big enough to hold the number of gallons of water needed to operate the waterfall. The sides of the pit should be vertical to maximize the capacity of the catch basin and minimize the surface area required for that capacity. The surface area of the hole should be smaller than that of the liner to be used so that there is enough excess liner to secure the edges so the water does not leak out. Also, the edges of the hole should be level so that there is no low edge where water would pour out of the hole. After the basin is dug, pack the dirt at the bottom with your feet or a tamper. If a reservoir such as a Rubbermaid storage bin or watering tub is to be used in the catch basin instead of the liner, the hole should be dug so that the reservoir fits in the hole up to its rim. The soil that is dug up can be used to add height to the waterfall. The stream of the waterfall should also be dug.
Lining the Waterfall Bed
Cover the hole with the liner and ease it into the hole to line the catch basin, smoothing out any wrinkles as much as possible. Make sure the outer edges of the liner lap over the edges of the hole so that the water will not leak out of the hole around the edges of the hole. Do not trim the liner until after the pump is installed because the pit must be filled with water so that the liner is trimmed in such a way that the water does not leak out of the catch basin, and the water can be emptied by the pump.
Installing the Pump
The water pump must be submersible. It must be powerful enough to pump all of the water from the catch basin through the length of the tubing back up to the head of the waterfall continuously. The biofilter can be removed since there will be no fish in the pondless waterfall. A five-gallon bucket or some other housing, with holes cut for the power cord, the tubing, and the water to flow into the pump, is placed in the lined empty hole. The pump is then secured inside the housing. Connect the tubing to the outflow of the pump using PCV fittings, glue and silicone sealant for a watertight seal. This tubing will bring the water from the pump back up to the head of the waterfall.
Other Plumbing and Electrical Work
Install the plumbing from the pump to the top of waterfall, whether a flexible tube is used and/or rigid piping, using the proper plumbing sealants at the joints to ensure a water-tight seal. See that there is a check valve to keep water from flowing backwards into the pump. Also an automatic fill valve can be installed from the water source to the catch basin to make the pond more maintenance-free. A timer and/or a remote control switch can also be installed on the pump.
Filling the Catch Basin
Before the hole is filled with gravel and rocks, a strong matrix such as 4" coex pipe segments can be placed in the hole. This will reduce the amount of gravel needed to fill the hole because it would allow more water to fill the hole that would otherwise be taken up by the gravel. Make sure the power cord is strung through one of the holes in the housing and can reach the power source. Then fill the hole around the matrix and the pump housing with gravel and top the surface with larger decorative rocks. A large flat rock can be placed over the pump housing itself.
The Head of the Waterfall
A waterfall box from which the water flows is placed at the top of the waterfall. This can be secured on top of a pedestal of soil or rocks to make it higher than the catch basin. A hole is dug for the waterfall box in the pedestal of soil, or if there is already a slope down which the waterfall will tumble, the hole is dug in the soil where the waterfall will begin. The box is placed in the hole and backfilled with the soil so that it is secure. Make sure the tubing and pipes that will bring the water back up from the pump will flow into this waterfall box, and out of it into the lined waterfall hole.
Placing the Rocks
Line the stream bed with rocks, placing them according to your waterfall design. Place the larger rocks first, then the smaller ones to fill in the spaces between them. Then use black expandable foam to fill in the spaces between the rocks so that the water will not leak out of the system until it finally falls into the rock basin. Let the foam harden and dry before filling the waterfall with water.
Filling the Waterfall
Fill the catch basin with water so that it just barely covers the top of the decorative rocks. Put decorative rocks on the lining around the edge to secure the lining and trim the lining. Landscape the edge of the liner and the waterfall box with rocks and plants so that the box and liner are hidden. Fill the waterfall box with water. Plug in the pump, turn it on, and do a test run to check for any leaks. After these are corrected, turn it on and sit back and enjoy the soothing sounds of your pondless waterfall.