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Streams
and Watersheds - Introduction
Method
3 = In relation to landscape and water table
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Figure
1-4
Whether
a segment of a stream is a "gaining" or a "losing"
reach depends on the relationship between the groundwater
table and the streambed. |
A third way
to classify streams is based on their relationship to the landscape
around them and the groundwater table. In this classification system,
streams are either "gaining" or "losing" streams
(Figure 1-4).
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A
gaining stream is one in which the channel bottom is
lower than the level of the surrounding groundwater table. Through
the course of the summer, water moves from the ground into the
channel.
-
A
losing stream is one which is above the groundwater
table, and water moves from the channel into the surrounding
ground.
Perennial streams
are generally gaining streams, while intermittent and ephemeral
streams are often losing streams. Many streams, however, are composed
of reaches (portions of a stream) which are gaining reaches and
others that are losing reaches.
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