A large number of multicriteria decision making (MCDM) methods have been proposed in the past and applied to water resources planning. The development and application of systems analysis techniques to assist decision makers in evaluating project alternatives having more than one objective in river basin planning is of recent origin.
In this paper an attempt is made to demonstrate the use of ELECTRE (ELimination and (Et) Choice Translating REality) I and ELECTRE-II techniques for water resources planning in one of the major river basins (Krishna river basin) of South India. The river basin consists of 8 reservoirs and a diversion work. Formulation of the problem is provided leading to an array of 27 alternative systems (different combinations of reservoirs with a minimum of three in each alternative) with 6 criteria related to: (i) irrigation, (ii) power production, (iii) drinking water, (iv) environmental quality; (v) floods and (vi) cost of the project. Out of the six criteria two, namely environmental quality and floods, are qualitative in nature. A set of best alternative systems with their partial ordering is obtained from ELECTRE-I, which forms the input for ELECTRE-II. Complete ordering of the reduced alternatives is achieved with ELECTRE-II. Sensitivity analysis shows that changing the weights assigned to each criterion has greater effect on the results than does changing the scales. However, neither effect is significant. Therefore it is recommended that ELECTRE-I be used for screening alternatives under consideration and ELECTRE-II for complete ordering of the reduced set.