Deviation of planned water demand from actual on farm water usage and suggestions for improvements: a case study from Uda Walawe irrigation scheme, Sri Lanka.
Water managers’ seasonal water allocation plans deviates from the actual water usage in the field due to many factors. Temporal and spatial variations that vary dramatically will affect the Field Irrigation Requirement (FIR) which is calculated. Therefore, the main objective of this paper is to see how planned FIR deviates from the actual on farm water usage in Uda Walawe Irrigation Scheme. The study proposes suggestions for improvements in meeting and balancing the water demands. Irrigation issues and the interviews with farmers and officials were used for the analysis. Results show that actual water usage is always higher than the FIR and water manager’s planned. There are various factors contributes for these discrepancy. Two lines of improvement are outlined. One is adjustment of the volumes allocated to each D. The second possibility of improvement points to greater involvement of farmers at the scheme and branch levels. A way to tackle this is to devise a transparent process of allocation at the scheme level whereby representatives from the different branch canals would participate in the definition of sharing arrangements. MASL’s role would be to ensure bulk allocation at the head of canal. FOs are responsible for finding ways to distribute this volume within their area
