Satellite remote sensing for assessment of irrigation system performance : a case study in India

This report contains the results of an experiment, perhaps the first of its kind, to use a package of satellite remote-sensing applications to develop performance indicators for an irrigation system. The experiment was performed by the International Irrigation Management Institute (IIMI) on a rice irrigation system in Bhadra, India that had received support under the National Water Management Project. In the study, several years of satellite data for the Bhadra Project were used to develop a disaggregated inventory for irrigated area and cropping patterns and to estimate the yield of a major crop, rice. The data confirmed that the National Water Management Project has significantly improved the extent of irrigation and increased agricultural productivity in the Bhadra irrigation system. In addition, problem distributaries that have subpar irrigation intensity, rice productivity, and equity have been identified for follow-up action to improve performance. The cost of satellite remote sensing application in this 100,000-hectare irrigation scheme amounts to US$0.10/ha per irrigation season at 1994-95 price levels. The cost would decrease to US$0.03/ha or less for schemes larger than 250,000 hectares. Improving the methodology will require the development of a vegetation index that is optimally sensitive to rice characteristics and better spectral modeling of rice yield. While the package of remote sensing applications developed under the study was done so for a rice crop irrigation system, it could be adopted for use in evaluating irrigation of other types of crops. (Author abstract, modified)