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1995
Conference Paper
Titel
Multicriteria decisions for water quality management of rivers
Abstract
The complexity and the variety of decisions on both quality and quantity have increased to such an extent that planning frameworks and management policies must be fine tuned to resource availabilitiy and to a sustainable development of river basins. Water quality management of rivers is always coupled with processes which are influenced by a lot of uncertain variables, by high-dimensional and often man-made disturbances and by restricted informationïs concerning organic and toxic impurities of the water body. Pollutionïs regulations are specified either in terms of river water quality or in terms of effluent standards. In the first instance, given a set of river standards, there is a large number of combinations of treatment levels at specific discharge points which will meet the requirements. In the second case, the water authority responsible fot setting the effluent standards must also recognize that a river has a limited assimilative capacity. In either case, multicriteria decision s are necessary in order to screen the array of possible courses of action and management alternatives. Most of the quality problems of river water are generated by matter discharged into a river as a consequence of human activities. Major emphasis is given to eutrophication and self-purification processes. Therefore, water quality simulation models for rivers may be distinguished by the type of natural processes which take place in the water body. The imbedding of such a model into multicriteria optimization procedures allows then the computation of compromises between counteracting processes andor conflicting goal functionals. For different river basins self-purification models were implemented into the computer aided decision support system CADS (Computer Aided Decision Support) to get Pareto-optimal alternatives for controlling the waste water input from point sources. The non-point sources of pollution of the river basin are described implicitly by the chosen modelling procedure . Multicriteria decisions are made for waste water input, for dissolved oxygen content of the water, for biological degradation of organic matter and for the costs of sewage water treatment and reconstruction of sewage water reatment plants. Management altenatives are given for retgional planning purposes.