A comprehensive statistical analysis of evaporation rates under climate change in Southern Iran using WEAP (Case study: Chahnimeh Reservoirs of Sistan Plain)

Abstract

In recent decades, climate change has caused an increase in anomalies in climatic variables and endangered critical infrastructures such as water resources. This change is of paramount importance for southern Iran, especially in the low-precipitation Sistan Plain. Therefore, it is crucial to consider variations in evaporation in the past and the trends of its future changes for water resources planning and management. To manage water resources in the region, this study was conducted to estimate variation in and rate of evaporation from the surface of Chahnimeh reservoirs for future decades using effective climate change models. The SDSM model was applied in 2050–2030 and 2080–2000 periods to simulate evaporation in the coming decades. The values of evaporation under climate change indicate an overall increase of more than 300 mm. According to the results of the WEAP model, much of the Chahnimeh reservoir’s water is consumed by the Zahedan and Zabol urban sectors. A lower share of water is allocated to the agricultural sector of the Sistan Plain compared to these two nodes. The withdrawal rates from these reservoirs will increase with increasing the population growth rate in the coming years. Furthermore, the evaporation rate will also increase. Hence, assuming a constant water flow discharge into the Chahnimeh reservoirs, severe water stress will occur in Sistan Plain and Zahedan water requirement.