Step 1: Design the pond and gather materials
A backyard pond doesn't have
to be big to have a big
impact. This pond is less
than 6 ft. long and just over 4 ft. across.
But with its striking stone surround
and sparkling waterfall, it can become
the centerpiece of any landscape.
This design is versatile, too. You can
make the pond twice as large as ours or
half the size. You can locate it on flat
terrain or tuck the stone waterfall wall
into a slope. And unlike most ponds,
this one won't leave you with a small
mountain of soil to deal with—you can
simply use the excavated soil to form a
berm behind the waterfall wall.
This pond will take anywhere from
one to three weekends to complete.
The size of the pond is one factor in
how long it will take. But the stone you
choose is also a major factor (for more
on that, see “Set the stone,” below). Our
cost for the basic pond materials,
including the liner, filter and pump,
was about $500. The stone may be free
if you can collect it yourself or it can
cost up to $1,000 if you choose expensive
stone at a landscape supplier.
This article won't tell you everything
you should know before you grab your
shovel. See other articles on this site for a guide to pond planning,
including advice on choosing a site.
Electrical codes require a GFCI-protected
outlet to power the pond's
pump. To see how to run underground
wiring and place an outlet anywhere in
a yard, search this site for “outdoor outlet.”
Pond and waterfall details
Figure A: Pond and Waterfall Details
Soil left over from digging
the pond hole can be used to
create a berm behind the tank.
Then add plants to give the
waterfall a lush backdrop.
Most home centers carry only a small range of pond
supplies. For the best selection, visit a large garden center
or landscape supplier. To get acquainted with the vast array
of choices, go online and search for “pond supplies.” Here's
what you'll need:
EPDM rubber liner: Make sure the material is at least
45 mil thick. To estimate the size, add twice the depth of
the pond to the length and width. Then add 3 ft. to both the
length and the width. Finally, add the height of the waterfall
to the length.
Underlayment: This feltlike synthetic material provides a
protective cushion under the liner. Buy the same amount
of underlayment as liner.
Pump: Pumps are sized by the amount of water they can
move, measured in gallons per hour (gph). One way to
select the size is to plan on 100 gph for each inch of waterfall
width. We wanted a 5-in.-wide stream of falling water
and chose a 500-gph pump.
Miscellaneous: 12-in. waterfall tank, filter media, pump
basket, lava rock, black foam pond sealant, silicone caulk,
pea gravel, tubing and connectors sized for your pump.
Tip: Before you
shop for water
plants at a garden center,
browse online to learn about
your plant options. Just do a
search for “water plants.”
Step 2: Dig the pond hole
We dug our pond in a kidney shape, but you can make yours
any shape you like. To experiment with different shapes, lay
out a garden hose or rope. But plan for the total size of your
water feature. The surrounding stone will extend 1 to 2 ft.
beyond the water's edge on three sides, and the waterfall wall,
tank and berm will cover 3 to 4 ft. behind the pond. When
you find a shape you like, cut through the sod around the
perimeter with a spade to mark the shape. Then start digging.
Toss the soil toward the back and sides of the pond where
you'll later build up the berm. Be sure to throw the soil far
enough so you don't have to move it a second time. When
you reach a depth of about 1 ft., create ledges along the sides
of the hole. Carve the ledges into undisturbed soil; don't try
to build them from soil you've already dug up. Make the
ledges at least 1 ft. wide. These ledges help prevent cave-ins
and provide a shelf for plants that prefer shallow water.
Slope the vertical walls of the hole slightly, about 1 to 2 in.
per vertical foot. Don't make the bottom of the hole perfectly
level. Instead, slope it slightly toward the end of the pond
farthest from the waterfall (about 1 in. of drop per horizontal
ft.). That provides a low spot where you can place the
pump and make it easier to drain the pond. Level the rim of
the hole so the surrounding stones will all rest at about the
same height above the water level (Photo 1).
Step 3: Line the hole with EPDM rubber
The pond liner is made of tough EPDM rubber, but it's not
puncture-proof. So inspect the hole before you line it. Cut
back any protruding roots and dig out any stones. If the soil
is filled with stones, spread an inch of sand over the ledges
and bottom. Next, line the hole with “underlayment,” a thick
synthetic fabric that cushions the liner against damage.
Overlap sections of underlayment by about 6 in. and run the
underlayment at least 1 ft. beyond the rim of the pond.
Lay the rubber liner over the pond and then push it
down so it roughly conforms to the inner shape of the hole.
Kick off your shoes and work in your socks when you're on
the liner to avoid puncturing it. Make sure the liner
extends at least 1 ft. beyond the edge of the pond on three
sides. On the waterfall side, you'll need enough excess to
reach the height of the waterfall. You'll run that extra
length of liner upward behind the stone to keep water in
and soil out. When the liner is in position, start filling the
hole with water, and work out the wrinkles as the pond
fills (Photo 3). Once water covers the liner, the pressure
won't allow any “dewrinkling,” so stay on top of the task.
Most important, don't leave any gaps between the soil and
Step 4: Set the stone
Surrounding the pond with stone can take just a few hours
or a whole weekend, depending on two things: First, it
depends on the shape of the stone you're using. Stone with
flat surfaces, like the flagstone we used, stacks up quickly.
Rounded or irregular stone requires lots of trial-and-error
puzzle fitting and triples the work. The second variable is
neatness. We chose a rough, informal look, with protruding
stones and fairly wide gaps between them. A more formal,
even and uniform look will take a lot longer to achieve.
Before you begin, lay out the stones and hose them off to
keep dirt out of the pond. Set aside three or four large, flat
stones as options for the waterfall ledge and the cap that will
cover the waterfall box. Then surround the pond with stone,
overhanging the water by a couple of inches to hide the liner
(Photo 4). Use fairly large stones that can't get accidentally
kicked into the water. You can set stones directly on the
liner, but a 1-in. layer of gravel makes leveling the stones
much easier. Be sure to use rounded “pea gravel” rather than
gravel containing sharp pebbles. We laid two courses of
stone at the front of the pond, but one layer of large stones
is enough to hold the liner in place.
As you build the waterfall wall, loosely drape the liner
up against the stone and pile soil against it. When you
reach the desired height of the waterfall, connect the supply
tube to the waterfall tank and attach the liner to the
tank (Photo 4). Next, set the waterfall ledge stone in place.
Slowly pour a bucket of water over it to make sure the
water flows off and into the pond. If the stone needs more
tilt, shim it with chips of stone.
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Step 5: Assemble the waterfall tank and pump
Set the tank in place over well-packed soil or stones,
with the outlet resting on the waterfall ledge. Then build
up stone around the waterfall ledge (Photo 6). You can hide
the tank with soil or stone. We used both and left one side
exposed so we could easily disconnect the supply tube.
That way we can pump all the water out of the pond for
repairs or cleaning. Cap the tank with a stone that's large
enough to cover it but small enough to move easily.
Connect the pump to the supply tube, set in a pump basket
and add lava rock. The lava rock provides a home for
bacteria and keeps debris out of the pump. Set the pump
and basket at the end of the pond farthest from the waterfall.
That way, water will circulate through the entire pond
before being pumped back to the waterfall. Place the filtration
bag in the waterfall tank and start up the pump. Watch
the water flow at the waterfall. Some of the water may run
back along the underside of the ledge stone instead of
falling directly into the pond. If so, create a drip line by
running a bead of clear silicone caulk along the underside
of the stone about an inch from the edge. If the water is
dirty, disconnect the tub from the waterfall tank, pump out
as much as possible and refill the pond. If the water is still
a bit murky, just give the filtration system a few days to do
Bacteria Clean the Water
There are lots of ways to keep pond water clean and clear—chemicals, high-tech filters, UV light systems. Some pond
owners skip all of these and simply change the water a few
times each summer as it becomes green or cloudy. We
chose a “biological” filtration system for our pond. The lava
rock in the pump basket and the “filtration media” (a bag
of plastic strips) in the waterfall tank simply provide plenty
of surface area where bacteria can grow. The bacteria
consume decaying leaves, fish waste and other stuff that
would otherwise make the water murky and feed algae. In
addition to being inexpensive and eco-friendly, biological
filtration is easy. All you have to do is remove the filtration
media twice each year and slosh it around in a bucket of
pond water (tap water will kill the bacteria).