Page 43 - 7166 - Rain Garden Handbook

Build
Places stakes at the Tie a string from Use the soil excavated from the uphill 2 37
uphill and downhill the ground level of side to fill the downhill area up so
sides and about 5 feet the uphill stake to that the area is flat. Very lightly tamp
apart along the length the downhill stake down the soil by walking over the fill
of your rain garden. so that it's level. after every few inches are added.

Leveling String

SLOPE
Original Surface
BERM

Cross Section View Soil Removed to Fill Berm
of Method 2

Create a berm at the downhill side to confine water in the rain
garden. For the correct height, build the berm up to the string.
Excavating On Slopes

If the rain garden area is sloped more than 5%, then consider one of the following
two methods for excavating soil to the necessary depth.

Method 1: Dig the downhill side to the desired depth and create a flat bottom.
This means that the depth at the uphill side will be more than the downhill
side, which is good for additional water storage but requires more digging.
Set the soil aside for reuse and/or disposal.

Method 2: An alternative method (shown on this page) to get the desired depth Stakes
on slopes is to excavate soil from the uphill end and use the soil to fill and
create a berm to get the desired depth at the downhill end. If you choose this
method, do the following:

• Place stakes at the uphill and downhill sides and about 5 feet apart along Plan View of
the length of the rain garden. Method 2
• Tie a string from the ground level of the uphill stake to the downhill stake so BERM
that it’s level. A small, lightweight line level works well for this.
• Rather than tie all strings to the stakes at once, work with one at a time and
in 5-foot sections so that the strings don’t get in your way.