A methodology for predicting the spatial distribution of evaporation rate in a catchment based on the Penman-Monteith (P-M) equation is suggested. The prediction is resolved into the four basic controlling components: net radiation, aerodynamic resistance, saturation state of the atmosphere and canopy resistance. Computer models of each component were then devised based on digital terrain analysis and tested for validity against observed data for clear sky conditions. Predicted values of potential evaporation compared favourably with those calculated from the observed data with a model efficiency of 0.80 and actual evaporation values were calculated based on this success. The digital terrain analysis enabled interpolation of the P-M calculations throughout the catchment allowing prediction of the spatial distribution of evaporation. -from Authors