Disappearing Waterfalls & Fountains
Sometimes it may be desirable to have a waterfall or a fountain without the pond. Someone with small children or someone who only wants a water display without fish or plants may prefer this approach to having an open pond. What is visible is an area of water worn pebbles with the fountain or waterfall disappearing into them. The pump and water are below the pebbles eliminating the danger of open waters.
The process is fairly simple. A reservoir is constructed either by digging in the ground or building up with a lumber or masonry structure. Depending on the size and length of the waterfall a shallow basin may be sufficient. You only need to build the reservoir large enough to hold sufficient water to keep the pump below water when the system is running. Unless you install an automatic water supply you may want the system to hold a little more than necessary to allow for evaporation. Most water basins for fountains are about one foot deep while those for waterfalls should be one and one half to two feet deep. This is because a waterfall generally uses more water within the system and the evaporation is greater.
After the reservoir is dug, you will then line it with underlayment and rubber pond liner just like a regular pond. The pond can’t just be filled with rocks. It needs a void space for the pump and easy access to service the pump. There are a couple of ways to accomplish this.
One option is to use a heavy-duty plastic grate that will support the weight of a layer of pebbles and anyone who might walk onto the pebbles. For most fountains a four-foot by four-foot reservoir works well. Plastic grates are usually sold two feet by four feet. These can be easily cut with a circular saw or hand saw to fit the excavation. A fountainhead can be used with this type of set up. The sound will be different with water falling back onto stone instead of water but the visual effect will be the same. A decorative spitter can be used as well. Another popular option is to use attractive ceramic urns. One or more of these could be used. A nice orientation is an urn tilted on its side with water filling the urn and then overflowing to the unseen pond. This also produces a nice sound with a large volume of water spilling out. An urn can be placed level with the water overflowing evenly around the rim. If the urn does not have a hole in the bottom then it will be necessary to drill out the bottom with a glass or concrete drill bit. Rubber tubing is run through the hole and epoxy putty can be used to seal around the tubing. The pump and tubing is added after the pond and grate structure is finished. After hooking up your urn or fountain to complete your fountain just cover with a decorative gravel allowing the gravel to spill outside the reservoir to provide the finished shape. The other option for constructing your reservoir is to use a waterfall well. A waterfall well is a strong plastic container with mesh openings to allow the water to enter freely into the chamber while offering support against the pressure of the stone. It also comes with a secure cover to allow easy access to the pump. This option will work better for large volumes of water such as large fountains or waterfalls. After the reservoir is dug and lined with underlayment and rubber pond liner place the pump vault on the rubber liner. Cut out an exit hole for the plumbing size that you are using and run the pipe or tubing. Fill the remainder of the pond with stone (irregular stone the approximate size of oranges is preferred) up to the top. A more decorative smaller stone can be used on top. Don’t use small gravel as a fill stone as it will not allow free movement of the water through the stone to the pump vault. Place concrete block, or even a double layer of brick for small water features, every foot or so over the bottom of the reservoir to support the grate. Cut out a square of the grate large enough to be able to get the pump in and out.
When constructing a stream with a disappearing waterfall, purchase enough waterfall pond liner to line the length of your stream plus enough to overhang into the pond before placing your stone. Run your plumbing to the top of the waterfall and hook up a waterfall tank to fit the size of your project. You will most likely want all of the water running over your waterfall and stream to flow over stone placed in the stream instead of running under the stone. Use mortar or waterfall foam to seal any stone to the liner at the waterfall areas. Finish placing stone to fill the reservoir, add plants if desired, plug up the pump and enjoy.