An Introduction to Landscape
Good drainage in the landscape is as
important as proper irrigation. Too much water in
landscaped areas can result in numerous plant diseases
and can even kill sensitive plants like expensive
evergreens. Overly wet turf areas are prone to soil
compaction and scarring from footprints and mowing
In addition, drainage around buildings is important to
prevent leaks and moisture
intrusion into building foundations and walls.
Drainage systems can use a variety of techniques to
remove unwanted water from an area, whether on a
residential, commercial, or golf course site.
Surface Drainage Systems
Surface drainage systems aim to collect excess surface
water from hardscaping, planter beds, window wells,
and specific turf areas where water tends to collect.
Water enters a surface drainage system through catch
basins, which have a sump area that collects debris to
prevent clogging of the piping.
basins and the drainage grates that go on top of
them are available in a variety of sizes and styles
depending upon the application.
Round drainage grates are
used in turf areas.
drainage grates are used for hardscaped areas;
walkways, driveways, parking lots, around swimming
drainage grates have a raised
"domelike" design to prevent debris from
building on top of the grate openings. These are used
in window wells, planter areas, and other applications
where bark mulch, stone, or landscape debris would
tend to cover drain openings.
The size of the catch basin should be
sized to the anticipated volume of water to be
collected. In addition the pipe carrying the water
from the catch basin should be properly sized to carry
water from all catch basins to which it is connected.
Always size a little larger than necessary for safety.
The additional material cost is minimal and mistakes
can be costly. If the drain will be exposed to weight
or traffic from above, you may need to consider a
concrete catch basin and/or a metal drainage grate.
The drainage line connecting the catch basins should
be of a solid (non-perforated) design. Both solid PVC
and corrugated plastic piping are acceptable.
form of the surface drainage system is the channel
drain. Channel drains are frequently used in
paved areas to collect water. They are essentially an
extended trough or catch basin covered by a long
grate. Typical channel drains can be 10’ long and
4" wide. Channel drains are also connected
together with solid piping.
The most frequently used form of sub-surface drainage
is the French Drain or underground collection drain.
This drain collects underground water from saturated
soils and carries it to a desired destination.
Sub-surface drains help carry water away from low
spots and can protect drainage sensitive plant
material. For information on how to construct a French
Drain from standard corrugated perforated drain pipe,
see the section entitled Constructing a French Drain.
Drain lines can be used to carry roof water from
downspouts away from buildings and planting beds.
Downspout drain lines can be especially helpful if the
natural grade around a building does not cause water
to move away from the foundation. Downspouts can be
connected to solid PVC or corrugated plastic drain
pipes to carry roof water away from the building.
If you have questions about the usage and application
of drainage equipment, we encourage you to contact
your nearest Transitions Landscape location. Our
advisors can explain to you the wide variety of
equipment that is available from Transitions Landscape
to meet all of your landscape drainage requirements.
Constructing a French Drain
French Drains collect sub-surface
water from poorly drained areas and carry it to a main
drainage line, dry well, ravine, or the street. French
drains can intercept water that is draining from
adjacent properties and carry it away before it enters
A French Drain is constructed using simple materials;
pea gravel or crushed rock, woven landscape fabric,
and a perforated drainage pipe (usually the corrugated
create a French Drain, dig a trench that will carry
water away from the area to be drained. Ideal places
to put French Drains are the bases of slopes, along
retaining walls, or any other area where water tends
to collect. Make certain that your trench is well
sloped so that water is encouraged to move through the
drain to the desired destination.
Line the trench with landscape fabric. Install a
4" or 6" perforated drain line at the bottom
of the trench, and backfill with gravel. The landscape
fabric should be wrapped all of the way around the
gravel to prevent mixing of the surrounding soil into
the gravel. This will keep the porous spaces in the
gravel open for the water to flow through.
In areas with severe drainage problems, multiple
perforated lines are used as water collectors or
interceptor drains. Water enters the perforations in
the drain lines when the surrounding media is
saturated and can be carried away more quickly than
just by percolating though the gravel.
If desired can connect the french drain perforated
lines into a main, non-perforated header line to
collect and carry the water to it’s intended