Multi-criteria decision support for annual rehabilitation programmes in drinking water networks

The selection of projects in the annual rehabilitation plan of a drinking water network requires the consideration of different aspects of existing deficiencies and expected improvements in the water supply system. With a field,study of, 12 water utilities in Europe, the objectives of drinking water network rehabilitation are identified These objectives are assigned to a number of "points of view" that can be divided in two types: internal and external points of view. Internal points of view mainly affect the cost and the monetary benefits of rehabilitation measures for the utility. External benefits of rehabilitation result from a better hydraulic performance of the-system, from improved system reliability or reduction of risks and therefore, they contribute to customer and third party satisfaction. Nine points of view are rendered more precisely by 17 criteria; The criteria are expressed by detailed cost functions, quantification of current deficiencies, assessment of risks or assessment of the pipe's potential contribution to zonal problems. Examples are given of criteria definitions and their calculation for using them in procedures of aiding decisions. This paper is a report on ongoing work in the CARE-W European project.