Agriculture Reference
In-Depth Information
or the water could be allowed to flow to
some point outside the parking lot to a
street storm water inlet, drainage swale,
or detention area. The parking lot grading
solution shown in Diagram C simply tilts
the parking lot in one direction toward a
catch basin or exit channel to be installed
in the lower corner of the lot. All three
solutions are commonly used to drain sur-
face water in parking lots, large expanses
of pavement, and grass fields. Generally a
selection is made based on the designer's
preference or in response to site design
considerations or governmental regulatory
requirements.
A parking lot with a crown down the center is shown in Figure 13.9.
Notice that the contours are curved, with the top of the curve at the
center of the lot, labeled as B. Point B is located at the top of the crown
in the center of the parking lot (high-
points) so that surface water is directed
by a cross slope formed by the curvature
of the contours toward the curbs running
along either side of the parking lot. The
water then runs along the curb to a catch
basin or drainage channel constructed
at the lower end of the parking lot. Tree
islands may protrude from the curb with
catch basins installed at the higher side of
the island, or a channel might be used to
allow the surface water to continue flowing
down-slope along the curb.
In the next chapter the topic of storm water management will be
presented. While the use of catch basins has traditionally been the “go
to it” solution for disposing of surface water runoff, current trends in
site grading seek grading solutions that keep surface water within a
A
B
C
CB
Tilted
Base
Crown
Va
ey
Figure 13.8
Three approaches for grading a parking lot or
large paved surface
100
101
102
103
104
Figure 13.9
Parking lot with crown
