PUB00070

• Year: 1998
• Title: Ground Water and Surface Water A Single Resource U.S. Geological Survey Circular 1139
• CWCB Section: Interstate & Federal
• Author: T.C. Winter, J.W. Harvey, O.L. Franke, W.M. Alley
• Description: Overview of current understandimg of interaction of ground water and surface water in terms of quality and quantity
• Publications - Doc Type: Historical

R

Effects of the Removal of Flood-Plain
Vegetation on the Interaction of
Ground Water and Surface Water

In low-lying areas where the water table is close to land
surface. such as in flood plains. transpiration directly from
ground water can reduce ground-water discharge to surface
water and can even cause surface water to recharge ground
water (see Figure 7). This process has attracted particular
attention in arid areas, where transpiration by phreatophytes
on flood plains of western rivers can have a significant effect
on streamflows. To assess this effect, a study was done on
transpiration by phreatophytes along a reach of the Gila River
upstream from San Carlos Reservoir in Arizona. During the
first few years of the 1 O-year study, the natural hydrologic
system was monitored using observation wells, streamflow
gages, and meteorological instruments. Following this initial
monitoring period, the phreatophytes were removed from the
flood plain and the effects on streamflow were evaluated. The
average effect of vegetation removal over the entire study
reach was that the Gila River changed from a continually
losing river for most years before clearing to a gaining stream
during some months for most years following clearing. Specifi-
cally, average monthly values of gain or loss from the stream
indicated that before clearing, the river lost water to ground
water during all months for most years. After clearing, the river
gained ground-water inflow during March through June and
during September for most years (Figure R-l).

Gila River, Arizona. (Photograph by Gregory Pope.)

71

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Before removal of phreatophytes
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Ffgure R-1. Removal of phreatophytes from the ffood plain
along a losing reach of the Gila River in Arizona resulted in
the river receiving ground-water inflow during some months
of the year. (Modified from Culler, R.C., Hanson, R.L., Myrick.
R.M.. Tumer, R.M., and Kipple, FP.. 1982, Evapotranspira-
tion before and after clearing phreatophytes, Gila River flood
plain, Graham County, Arizona: U.S. Geological Professional
Paper 655-P.)