Abstract
Human activity is the most significant factor driving water demand. In this paper, we quantify the water demand in the transboundary 3S River Basin (Sesan, Sekong and Srepok) according to projected societal and economic developments, the so-called Shared Socioeconomic Pathways (SSPs). We considered the water demand across four water use sectors, namely domestic, irrigation, industrial and environmental, and derived estimations that were compatible with the three SSPs (SSP1, SSP2 and SSP3) for three periods: the 2030s, 2060s and 2090s. Three population projections, corresponding to the three SSPs, were made using the cohort component and ratio methods. The Land Change Modeler (LCM) model was employed to prognosticate the future land use land cover change. By the end of this century, the basin's population is projected to increase by 60%, 117% and 139% under SSP1, SSP2, and SSP3 respectively. Agricultural and urban areas are predicted to increase by 33% and 100% in the 2090s, respectively. Consequently, total water demand would increase by 98%, 101.9% and 102.8%, under SSP1, SSP2, and SSP3 by the end of this century respectively. The results of this study will help policy makers and planners in developing appropriate water supply plans to tackle the continuous but uncertain increases in future demand.
