Water is a keystone resource. In abundance, it
supplies cities, industries, and agriculture. To
maintain healthy natural and human ecosystems,
water must not only be present in adequate
quantity, but it must be of suitable quality for its
intended use. Water quality depends on the
amount, or load, of contaminants, both natural and
anthropogenic, that it contains. Accurate
assessment of these contaminants requires that the
amount of water flowing in a stream or river be
known. To quantify streamflow in a given stream
or river and the variation of that flow through time,
it must be measured by use of stream gages.
Monitoring water flow is fundamental to managing
and protecting water resources, and requires a
collaborative effort by all interested parties,
including Federal, State, and local government
agencies.