Environmental Engineering Reference
In-Depth Information
Figure 14.8
Downslope water pathways (a) and (c) and their
influence on components of the flood hydrograph (b).
Vegetation and soil humus largely preclude Horton flow in humid climates but soil
throughflow may emerge as
saturated
overland flow towards valley floors.
The impact of these rapid transfers is dramatic but short-lived, leading to a sharp rise
in the constant or slowly declining baseflow of the hydrograph. This
rising limb
has four
important parameters (Figure 14.8b). The
peak discharge value
(PDV) represents the
maximum event discharge, prior to its recession down the
falling limb
, and is separated
by lag time from the precipitation peak.
Time of rise
is determined by the antecedent
storage capacity and connectivity of catchment components to the channel. This includes
the upstream
channel network
for trunk river hydrographs (Figure 14.9).
