The calculation of evaporation from soil surfaces is of critical importance in predicting the surface water balance for soil cover systems constructed on waste disposal sites and for geotechnical problems where the prediction of pore-water pressures is important. There are several well-established approaches available for predicting evaporation from horizontal soil surfaces, but the issues that affect evaporation from soil slopes have not been fully investigated for geotechnical applications. The importance of variations in solar radiation with respect to evaporation from soil slopes is examined here, and a method to predict the solar radiation on soil slopes is presented. The method is applied to a fully three-dimensional surface, based on the digital map of a soil cover placed at a mine site, to illustrate variations in potential evaporation over the surface of the site. The implication of radiation variations for actual evaporation on slopes is also illustrated. The results show that north-facing slopes at greater latitudes in the northern hemisphere can receive significantly less net radiation than horizontal or south-facing slopes, resulting in less actual evaporation.Key words: slope, evaporation, solar energy, soil cover, water balance.
A STATISTICAL COMPARISON BETWEEN MET STATION DATA AND REMOTELY-SENSED DATA FOR CALCULATING REQUIRED STORAGE IN WATER BALANCE COVER SYSTEMS
