56
Exercise 5
PRECIPITATION ~
+ + f ~
-
.................
·::·: : : :~:g;ttg:X~U~:~::: :::··
t EVAPORATION
t.,....~t . . . . +....:.+-..:::::~~~~~~O~VERLAND FLOW
INTERFLOW
PERCHED
~
WATER
~ .........
INFILTRATION
TABLE
IMPERVIOUS LENS
WATER TABLE
GROUNDWATER FLOW
Figure 5.1. Major pathways of precipitation and the runoff phase of hydrologic cycle.
DRAINAGE AREA
A variety of methods have been proposed for ordering the tributary streams in a
drainage network [cf., Gregory and Wailing (1973)]. The Horton-Strahler method
(Horton, 1945; Strahler, 1952) is probably the most widely used in the United States. In
this method each headwater or "finger-tip" tributary is designated as the first order.
Figure 5.2. Stream orders according to the
Horton-Strahler method.