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

Lakes and wetlands also have distinctive
biogeochemical characteristics with respect to
their interaction with ground water, The chemistry
of ground water and the direction and magnitude
of exchange with surface water significantly affect
the input of dissolved chemicals to lakes and
wetlands, In general, if lakes and wetlands have
little interaction with streams or with ground
water, input of dissolved chemicals is mostly
from precipitation; therefore, the input of chemi-
cals is minimal. Lakes and wetlands that have
a considerable amount of ground-water inflow
generally have large inputs of dissolved chemicals,
In cases where the input of dissolved nutrients
such as phosphorus and nitrogen exceeds the
output, primary production by algae and wetland
plants is large, When this large amount of plant
material dies, oxygen is used in the process of
decomposition, In some cases the loss of oxygen
from lake water can be large enough to kill fish
and other aquatic organisms,

The magnitude of surface-water inflow and
outflow also affects the retention of nutrients in
wetlands, If lakes or wetlands have no stream
outflow, retention of chemicals is high, The
tendency to retain nutrients usually is less in
wetlands that are flushed substantially by
throughflow of surface water, In general, as
surface-water inputs increase, wetlands vary from
those that strongly retain nutrients to those that
both import and export large amounts of nutri-
ents, Furthermore, wetlands commonly have a
significant role in altering the chemical form of
dissolved constituents, For example, wetlands that
have throughflow of surface water tend to retain
the chemically oxidized forms and release the
chemically reduced forms of metals and nutrients,

Eutrophic lake in Saskatchewan,
Canada. (Photograph by
James LaBaugh.)

"The chemistry of ground water
and the direction and magnitude
of exchange with surface water
significantly affect the input of dissolved
chemicals to lakes and wetlands"

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