Process-based Analysis of the Climate Change Impacts on Primary Hydro-Salinity of the River Ecosystems

Given that accessible freshwater resources are becoming more scare, knowledge about the climate change effects on sources of primary salinity in water resource systems is getting more important. Most of limited preceding works on analysis of climate change induced salinization of the river ecosystems have employed simplistic empirical models. Accordingly, this paper deals with developing a conceptual module for primary salinity modelling in framework of a physically-based hydrological model, i.e. Soil Water Assessment Tool (SWAT), for analyzing climate change impacts on catchment-scale primary hydro-salinity. The developed methodology is applied to saline Shour River located south of Iran, which recently has been facing water shortage and restriction due to the river’s salinity. The model is validated according to historical records of the river’s discharge and salinity using Sequential Uncertainty FItting ver. 2 (SUFI2) algorithm, where acceptable Nash-Sutcliff values of 0.73 (0.76) and 0.56 (0.65) is respectively achieved for discharge and total dissolved solids (TDS) in calibration (validation) period. The calibrated model is then utilized for climate change scenarios analysis where climate time series projected under conditions of A2, B1 and A1B scenarios are introduced to the model. The results indicates how time series of river salinity increases for both near future, years 2046–2064, and far future, years 2081–2099, with respect to current condition.