WATER QUALITY MANAGEMENT IN CONNECTED CATCHMENT- SHALLOW LAKE SYSTEMS - Integrating GIS, Remote Sensing, and Mathematical Modelling for Surface Water Quality Management - page 42

intake, the Ministry of Water Resources and Irrigation monitors ambient water quality, and the
Ministry of Environment and the Ministry of Health both monitor water quality for compliance testing
(Abdel-Dayem, 1994). There is no cross-ministerial mechanism to review policies and mandates,
provide for monitoring coordination, nor facilitate the exchange of information and data
The identification and categorization of water quality problems does not always take place in
appropriate and planned measures. Identified water quality problems may fall into different categories
requiring application of different management tools and interventions for optimal resolution of the
problems. For example, it is important to know whether a certain water quality problem pertains only
to a local community or whether it is a national problem. If a problem exists at the national scale it
might be necessary to consider imposing general effluent standards, regulations or other relevant
measures, also the type of management tools to be applied will vary. By contrast, if the problem is
limited to a small geographic region it might only be necessary to consider issuing a local by-law or to
intervene to settle a dispute through mediation.
It may also be useful to categorize water quality problems as either "impact issues" or "user-
requirement issues". Impact issues are those derived from human activities that negatively affect water
quality or that result in environmental degradation. User requirement issues are those which derive
from an inadequate matching of user specified water quality requirements (demand) and the actual
quality of the available resources (supply). Both types of issues require intervention from a structure or
institution with powers that can resolve the issue in as rational a manner as possible, taking into
consideration the prevailing circumstances. According to the traditional water pollution control
approach, user-requirement issues would often be overlooked because the identification of such
problems is not based on objectively verifiable indicators. Whereas an impact issue can be identified
by the presence of, for example, a pollution source or a human activity causing deterioration of the
aquatic resources (e.g. eutrophication), user-requirement issues are identified by a lack of water of
adequate quality for a specific, intended use.
In many countries, no comprehensive and coherent policy and legislation exists for water pollution
control or for environmental protection. This does not prevent water pollution control from taking
place before such policies have been formulated and adopted, but the most efficient and effective
outcome of water pollution control is obtained within a framework of defined policies, plans and co-
ordinating activities. There may be obvious shortcomings in the existing situation that need urgent
attention and for which remedial actions may be required independently of the overall general policy
and planning. Such interventions and remedial actions should be taken whether or not an overall
policy exists. A lack of policy should not delay the implementation of identified possibilities for
obvious improvements in water pollution control. The only means to develop these policies and take
decisions for remedial action, is having a reliable and adequate decision support tool (DSS) that is
based on using appropriate management tools. Identification of the existing water quality problems
and understanding the behavior of water systems under the impact of these problems is an important
need before policy and decision s can take place. Nowadays, with the exceeding and complex water
quality problems, and with vast developments in data acquisition and modeling tools, it is not
sufficient to deal with water quality quantitative information in the form of statistical analysis or
trends.
Modelling tools are treated here as any set of instructions based on a deterministic theory of cause-
effect relationships which are able to quantify a specific water quality problem and thereby support
rational management decisions. This can be done at different levels of complexity, some of which are
discussed below form the application point of view:
Loadings : Preliminary decisions can be taken with respect to reduction of loadings from a
ranking of the size of actual pollution loadings to a particular receiving water body. The rationale
is to assess where the greatest reduction in pollution can be obtained in relation to the costs
involved.