A transient computer model has been developed to investigate the effect of a black plastic bubble sheet on the evaporation process in a shallow salt pond. The transient behaviour of the evaporation process and the influence of various parameters such as the depth of the brine layer, weather, and wind speed are discussed and compared for ponds with and without a black plastic bubble layer. The results show that the influence of soil properties on the evaporation process is small for a pond with a plastic bubble sheet, and that the evaporation rate may be higher with the black sheet.