Environmental Engineering Reference
In-Depth Information
5.2 Management decisions and water quality status
Under the integrated approach to the water resources management practice and pollution
control, a wide spectrum of activities should and could be envisaged as part of any
pollution abatement program, but they should be viewed in their inter-relation and mutual
interdependence. In general, we could sub-divide them in two major groups: prevention
(non-structural) or pro-active measures; and pollution abatement by detention and
treatment, also called reactive (structural) measures. As emphasized before, prevention
measures should have precedence and priority with respect to diffuse pollution control.
The information, presented in the previous section, shows that the managing authorities
understand the need for such an approach and are aware of the major sources and
consequences of diffuse pollution. They also identified the need for a more detailed
survey of diffuse pollution from high-density urban areas, landfills and informal sector,
with respect to the urban surface and ground water quality. Results of specific case
studies, investigating such types of diffuse pollution sources are presented in subsequent
chapters. However, it should be mentioned that the need for acquiring reliable
information on the water quality status of natural and man-made bodies, in order to
support the decision making process, is of high priority.
Water resources management is an important issue for any country, but in the
Southern African region it is even of greatest importance considering the scarcity of this
resource and the underdeveloped nature of significant parts of this geographic region. For
this reason, the need to make informed decisions regarding the optimal use of available
resources is essential. Diffuse pollution regulation and abatement requires a water quality
objective orientated approach of the legislative structure, defining the main qualitative
objectives to be achieved with respect to the beneficial use of each specific water body
(or section of it), based on a catchment principle. The formulation of the water quality
objectives is closely related to the quantitative aspect (available water resources, demand
estimation and allocation for different purposes and to different consumers). Also, it is
related to the type of beneficial use, e.g. a water body, which is designated for the
purpose of irrigation only, does not need to have restrictions regarding nutrient
concentrations. In addition, surface water bodies in the specific cases of large rivers,
lakes or dams, have a considerable natural capacity to self-purify and to restore their
water quality. They could assimilate a given pollution load in addition to the one present
naturally. Correspondingly, the correct formulation of the water quality objectives and
corresponding beneficial use of water resources would depend on the correct estimation
of the pollution loads, supplied to the corresponding water body and the assessment of its
assimilative capacity. These are site-specific parameters, depending on different factors
(geographical, social, economical, etc), which could not be acquired easily from literature
sources or adapted from similar case studies. Therefore, it is in the interest of each nation
to have its own data sets, representing quantitative and qualitative parameters
characterizing the status of water resources. Such data should be obtained based on
regular and continuous monitoring programs, with specific objectives and quality
assurance tools. Unfortunately, the need for reliable water quality data is usually
underestimated in the countries of the region and often is not considered during the
process of water resources management. An example is the survey, reported in the
Search WWH ::




Custom Search