Low cost satellite data for monthly irrigation performance monitoring: benchmarks from Nilo Coelho, Brazil

Irrigation performance indicators can help water managers to understand how an irrigation scheme operates under actual circumstances. The new contribution of remote sensing data is the opportunity to study the crop growing conditions at scales ranging from individual fields to scheme level. Public domain internet satellite data have been used to calculate actual and potential crop evapotranspiration, soil moisture and biomass growth on a monthly basis in the Nilo Coelho irrigation scheme, Pernambuco, Brazil. Satellite interpreted raster maps were merged with vector maps of the irrigation water delivery system. Monthly values of a minimum list of irrigation performance indicators for the various service units in the pressurized Nilo Coelho scheme were determined. Nilo Coelho is a good performing scheme. The performance can be improved further if 25% irrigation water is saved from February to July. The benchmark figures from this modern irrigation system are presented for comparative analysis with other systems. The acceptable ranges in space and time are presented. On average, 65% of the lateral pumping units on a monthly basis fall within the acceptable limits of irrigation performance. Low cost irrigation performance data based on low resolution satellite images (US$ 1/ha) will help the management team to focus on specific pumping units, and discuss alternative irrigation and farm management strategies with the stakeholder