Environmental Engineering Reference
In-Depth Information
Recently, GISs find very wide applications in the field of water resources management in
developed countries. Their applications in developing countries could be encouraged as
well, but in many cases, it is restricted by the lack of data availability and the lack of
culture to keep records of a different nature. The implementation of GIS in the water
resources management practice in general, and the diffuse pollution control and
abatement practice in particular, could become a valuable tool to support the decision-
making process.
5 REGULATORY APPROACHES AND INSTRUMENTS
Considering its nature and generation, diffuse pollution is difficult to be evaluated,
regulated and controlled. This process should be viewed as an integral part of the process
of regulation and control of water quality in general. In order to understand it, basic
definitions, principles and philosophies of water quality regulation is essential.
The practice of water pollution control in the past years was focusing on point sources
of pollution only. Thus, in many countries, the regulatory basis was orientated in this
direction, and did not have provision for the control of diffuse pollution sources. While in
the USA and EU countries, new regulatory instruments have been developed in order to
account, control and prevent water pollution from diffuse origin, in many countries such
instruments do not exist, or are in an initial stage of development. In some cases the basic
regulatory instruments are available but not implemented. For this reason, the proper
understanding of existing regulatory instruments at local, national and international level,
and their upgrading to include control and abatement of diffuse pollution sources, is a
very important aspect of the contemporary development in the practice of water pollution
control and water resources management.
5.1
Basic definitions and concepts
Water pollution regulatory instruments include a big variety of documents, which vary in
different countries. One general classification could be made, as follows:
• Water Quality Standard - this is a document defining water quality objectives and
restrictions, whic his recognised in enforceable environmental control laws of a level
of government. It is a definite rule, principle, or measure established by authority.
Since established by authority, it is official or legal. However, because some
documents are termed standards, it does not mean that they are rationally based on the
best scientific knowledge and engineering practice.
• Criteria - this is scientific data, evaluated to derive the recommended limits for different
water uses. A “criterion” should be capable of quantitative evaluation by existing
analytical tests, and also should be capable of a definite resolution. In contrast to
standards, criteria have no connotation of authority. When data is gathered in order to
be used as a yardstick of water quality, “criterion” is the proper term. Water quality
criterions are the benchmarks of the process of pollution control and they are
internationally applicable in most cases. They are usually determined based on
scientific investigation with respect to the effect of different constituents on human
health, environment, crops, and others, e.g. toxicity tests.
