A DECISION-SUPPORT APPROACH FOR IMPROVING STRATEGIC MANAGEMENT OF COLLECTIVE IRRIGATION SCHEMES IN NORDESTE (BRAZIL)

Abstract

The management of collective irrigation schemes raises complex issues regarding water management and choice of water pricing. Several approaches have been suggested to tackle these issues, such as systemic analysis or participatory appraisal methods. This paper shows how an approach based on management sciences and intervention-research on the used with the Maniçoba scheme in the Petrolina-Juazeiro area. This case is characterized by a management transfer from a para-statal agency to a water users association called district. This newly established manager has faced major uncertainties that put the scheme viability at risk. Perennial crops have progressively replaced annual crops, altering the farmers" water demand. Both payment defaults and an inadequate water pricing system impact on district's financial balance. The approach aims at supporting the scheme manager addressing strategic issues rather than mere daily operational adjustments. Based on a conceptual framework of collective irrigation scheme management, it focuses on (i) interactions between water supply and demand and (ii) the choice of the water pricing system. In both cases simulation tools have been developed to support prospective reflection by simulating and comparing alternative scenarios. WaDi model calculates the water supply-demand ratio according to changes in hydraulic infrastructure and water management rules, while a second spreadsheet program calculates the impact of water pricing on farmers' incomes and the manager's financial balance. Various ways of improving the small-scale farmers' water supply were compared, e.g. by implementing night irrigation and individual reservoirs. Alternative water pricing systems were simulated in order to increase the district's recipts and to secure coverage of its fixed expenses. It included optional contracts adjusted to different farm types. A role playing game was then organized to improve the stakeholders' understanding and to stimulate discussions regarding the choice and the payment of the water. This approach provides a relevant framework both to understand current scheme operation and to support stakeholders' prospective reflection. Tarify howuver it needs further research regarding the assessment of their assumed learning processes.