Build an Above-Ground Water Garden

!±8± Build an Above-Ground Water Garden

Are you interested in having a wildlife habitat in your back yard next spring? The time to think about doing that is now in the wintertime. One of the main needs of your backyard visitors is the need for water.

Here are instructions for building above-ground water gardens.

To build an above-ground water garden

This section describes how to build an above-ground 4' x 8' pond that holds about 350 gallons of water. You will need:

(15) 8' landscaping timbers

12 pieces of 17" rebar

45 mil EPDM rubber sheet

The pond will measure 18" above ground and has a deep area in the middle made by digging out a 4' x 2' x 18" deep hole with steeply angled walls. This leaves a generous 10" wide underwater ledge on which to place plants. Fish like the deep section that also stays cooler because of increased contact with the ground.

To begin

First select the area where you will place your pond. The area of ground where the timbers will lie must be made level and firm or the pond will look crooked when it is finished.

To build the sides take five of the 15 timbers purchased and cut them exactly in half to yield the 10 pieces about 4' long.

All the timbers must be drilled with three holes each. These will receive the pieces of rebar that hold everything together. Accurate placement of the holes is important to easy assembly; otherwise you may need the old sledgehammer.

The easy way to do this is to make a template that quickly and accurately marks the drilling locations for the three holes needed on each timber. This is a really important step in reducing the work in the drilling and assembly.

Making the template

The template is made from a straight piece of 1' x 4" lumber 8' long. From the right hand end, measure along the centerline and place marks at 2 3/16", 6 9/16", 45 13/16" and 93 17/16". Carefully place a small nail on the centerline at each mark and drive through the board until each protrudes about 1/8" out the other side. Be careful to keep the nail straight up and down while driving it.

To use the template, lay it on one of the 8' timbers with nail points down. Match up the right hand ends, center up the width and tap the nails at the 2-, 6- and 93-inch positions. This will make prick marks where holes need to be drilled. The nail at the 45" point is used to mark the third hole on the 4' timbers. I used a 3/4" wood bit for easy assembly, but could have used 5/8". The very bottom timber was only drilled to 2" depth to form a pocket to hold the rebar.

Stand up your 12 pieces of 17" rebar in the pockets and start adding the remaining timbers as they are drilled. Note that each subsequent timber has its hole pattern in the opposite direction from the one below it.

Adding the liner

Before adding the liner, check for rocks and sharp objects on the ground. You can add some thick corrugated cardboard on the sides to cushion it against the timbers. Start with a little water in the deepest part to anchor the liner as you center it up. Try to distribute the excess liner symmetrically around the pond. Much of the excess will end up near the corners where some large folds can be made. Add a little water at a time and continue to improve on the smoothness of the folds until the whole liner is filled. The folds will look kind of lumpy and ugly until the finish boards are finally added to hide the top.

The top

Finish the top with 2'x6" pressure treated boards fastened on with deck screws. After the finish boards are firmly fastened, use a utility knife to slice away remaining excess liner.

Pump and filter The installation of a submerged pump and filter is highly recommended. The output line from the pump to the filter can come over the top of the finish boards, but a neater installation can be made by carefully drilling a horizontal hole through the 2'x6" deck and putting some copper tubing through it. Automobile heater hose connects one end of the copper tubing to the pump underwater and the other end to the filter at the back of the pond. Secure both ends to avoid dislocation by stray animals that could result in accidentally pumping out all water from the pond.

In another article we'll talk about easy to find and grow water plants for both.