The rapid growth of urban areas throughout the world and advances in technology
and industry to meet society’s ever increasing demands for more goods,
energy, etc. have greatly increased the potential for environmental pollution. They
have also contributed to an increasing awareness of and concern for the environment.
Population density and advanced technology continue to place increasing
demands on society to control the quality and conserve the supply of water.
Increasingly strict legislation and continuing public interest in conservation and
environmental matters have emphasized the importance of flow measurement.
Uniform and reliable measurement data are needed to identify the resource levels
and quality of bodies of water, to determine the results of conservation and quality
control efforts, and to enforce water conservation and quality regulatory requirements.
The majority of recent interest in flow measurement has centered on water
quality regulatory requirements. For example, in the United States, federal law states
that “…the purpose of self-monitoring and reporting effluent data is to permit
federal and state regulating agencies to follow on a continuing basis, the discharger’s
effluent quality trends as well as specific variation from established limitations.”
Local agencies in the U.S. are required by the same legislation to establish a
local surcharge on industrial waste to insure that these users pay their “fair share”
of the cost of existing and new treatment facilities. Their “fair share” entails the
measurement of both the quality and the quantity of industrial discharge. Thus, an
economic value has been placed on industrial waste, and it is important for both
industrial dischargers and municipalities to be able to measure and record flow
There are variations of environmental monitoring regulations throughout the
world. There are often layers from national to regional, and a number of local levels
for regulatory law as well as enforcement agencies. The purpose of this handbook,
however, is not to define the protocols of environmental flow monitoring, but to
address the field in general. You should always consult your local regulatory agency
regarding the standard practices and requirements for your specific monitoring
Of course, flow measurement still is of great importance in more traditional
areas such as irrigation, stream measurement, and sewage treatment plants. It also
has other applications, for example, in storm and combined sewer flow studies, in
sedimentation work, in runoff studies, and inflow and infiltration isolation.
As Kirkpatrick and Shelley state: “Measurements of quantity of flow, usually
in conjunction with sampling for flow quality, are essential to nearly all aspects of
water pollution control. Research, planning, design, operation and maintenance,
and enforcement of pertinent laws—all are activities which rely on flow measurement
for their effective conduct.”
Thus in the context of modern society, there is an ever increasing need for
simple, accurate, and reliable methods of flow measurement. These needs are
usually dictated by legislation, but in a larger sense are dictated by society’s desire to
reverse the trend of increasing environmental pollution, and to ensure a clean,
livable planet for this and future generations.