An improved multicriterion analysis approach to avoid subjectivity in irrigation water allocation decisions
The performance of the century-old irrigation system of Pakistan (i.e. warabandi) has been evaluated using socio-economic data gathered by the author in multiple farmers surveys (n=278) conducted in Indus Basin of Pakistan. In the surveyed regions, the warabandi system was performing poorly. In-built rigidity in water allocations was found as main reason behind its poor performance. The results from the farmers surveys also revealed that the objective of increasing irrigation water productivity would never be attained under the warabandi arrangements. Hence, a completely new concept that could replace the warabandi system and improve the productivity of limited irrigation water should be introduced. My aim was to find a better way to allocate the scarce water resource between farmers. In this study, I have introduced a new concept for determining water allocations among the farmers, which is based on a multicriterion decision making (MCDM) approach. The consideration of multiple criteria in irrigation water allocations would improve irrigation water productivity. Upon an extensive survey of well-known MCDM methods, I concluded that all previously existing MCDM methods were using subjective inputs, usually from a single modeller, to establish priorities of alternatives and therefore, a predetermined solution could easily be obtained. I have developed an approach based on conjoint analysis which removes that subjectivity from the chosen MCDM method (i.e. ELECTRE). Interval scales and relative importance criteria weights, two usually subjective inputs in ELECTRE, are objectively estimated from the conjoint analysis study. For that purpose, the author designed a conjoint questionnaire and administered it to 62 farmer respondents in face-to-face interviews. Conjoint analysis, which does not appear to have been previously used in water resources or allocation studies, is a method for creating the interval scales and the relative criteria weights objectively from the respondents judgements on the importance of conjoint objects. The objective estimation of these two important factors is a completely new development which can assist in the unbiased determination of the best division or allocation of scarce water resources between farmers. The approach is applied, as a demonstration, to a region with nine distributary watercourses to determine which of the distributaries should have the highest priority for allocation of the regional water.
Multicriterion Decision Making, Rotational Irrigation Delivery System, The warabandi, ELECTRE, Subjectivity, Pakistan
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