Multiobjective river basin planning with qualitative criteria

The impact of alternative river basin development strategies is examined from a multicriterion viewpoint using the ELECTRE I and II techniques. The main stem of the Santa Cruz River in the vicinity of Tucson, Arizona is taken as a case study. A systematic formulation of the problem is provided leading to an array of 25 alternative systems versus 13 criteria, only 5 of which are quantified. A procedure for ranking these alternatives is presented which uses ELECTRE I to obtain preference graphs as input into ELECTRE II, which is then used to obtain the ordering. Sensitivity analysis shows that changing the weights assigned to each criterion has a greater effect on the results than does changing the scales. However, neither effect is very significant. It is recommended that ELECTRE I be used for screening purposes to narrow the set of alternatives under consideration. ELECTRE II can then be applied to this reduced set to obtain a complete ordering. For the case study the preferred systems include reservoirs and channelization and the least preferred systems include new groundwater development.