The report describes the development and application of a method of evaluating the economic benefits of sediment control measures, utilising data that is typically available in developing countries.
The first section of the report summarises the method for evaluating the economic benefits of sediment control. The method uses conventional cost benefit calculations, incorporating in the \"without project\" scenario the estimated costs of the future loss of productive potential due to sedimentation. \"With project\" costs are calculated on the basis that sustaining an acceptable irrigation service to the scheduled area, and reducing desilting costs are primary objectives.
The second section of the report describes a verification of the evaluation procedure at the Agno River Irrigation System in the Philippines. Sediment control facilities consisting of a vortex tube sediment extractor and low level sluicing gates were constructed at the head of the main canal. Actual performance was then monitored and results compared with predictions made from use of the evaluation procedure.
The report concludes that low cost sediment control structures, such as the one studied, will pay for themselves in a few years through reductions in desilting costs.
HR Wallingford, UK. 56 pp.