Groundwater Flow
The content in this newsletter has been created and supplied by the United States Geologic Survey http://ga.water.usgs.gov/edu/earthgwdecline.html. This USGS site, titled "Water Science for Schools," is a great resource for ALL ages, especially for those who prefer to dismiss cumbersome technical lingo.
Natural Conditions:
Water is recharged to the ground-water system by percolation
of water from precipitation and then flows to the stream through the
ground-water system.
Water Level Declines:
Water pumped from the ground-water system causes the water
table to lower and alters the direction of ground-water movement. Some
water that flowed to the stream no longer does so and some water may be
drawn in from the stream into the ground-water system, thereby reducing
the amount of streamflow.
Groundwater Quality:
Contaminants introduced at the land
surface may infiltrate to the water table and flow towards a point of
discharge, either the well or the stream. (Not shown, but also
important, is the potential movement of contaminants from the stream
into the ground-water system.)
Environmental
Effects of Groundwater Development:
Water-level declines may affect the environment for
plants and animals. For example, plants in the riparian zone that grew
because of the close proximity of the water table to the land surface
may not survive as the depth to water increases. The environment for
fish and other aquatic species also may be altered as the stream level
drops.
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