MAPPING SPATIAL VARIABILITY IN CROP EVAPOTRANSPIRATION AND DEFINING SPATIAL RESOLUTION UNITS FOR CROP WATER FOOTPRINT ASSESSMENT AT RIVER BASIN SCALE

Abstract

Aim of this study was to develop amethodologyfor defining the spatial resolutionunit (SRU)for WF assessment at river basin scale. On the basis of soil type and agroecology, the Betwa river basin was divided in to smaller but homogeneous agriculture production units (APU). Spatial variability in ETc of 12 major crops was mapped using geostatistical interpolation.K-means clustering was applied to combine the APUs to form the SRU such that ETc variation within the SRU is minimum. Four distinct SRUs were identified for kharif and rabi crops. Variation in ETc of crop within the AESRs of the basin ranged between 22.0 (AESR 10.3) to 33.9 mm (AESR 4.4) while it reduced to 11.7 (SRU1) to 18.6 mm (SRU4) within the delineated SRUs. Based on the tests of significance, SRUs were found to be a better resolution unit for WF assessment at river basin scale. The proposed methodology of SRU delineation is robust and can be replicated in other river basins.