Climate Change Trend in Fars Province, Iran and Its Effect on Groundwater Crisis

Abstract

In recent years, Fars Province in southern Iran has suffered from drought and faced with serious challenges in the water sector, including but not limited to rising water demand and shortage, declining groundwater levels, deteriorating water quality, and increasing ecosystem losses. Climate change is blamed for water crisis. To investigate the trend of climate change and its effect on water crisis, the change-point years in temperature, precipitation and groundwater level time series in Fars Province, Iran were determined for the period 1974-2014 (40 years) and compared with the change year in groundwater level, river discharge and the Southern Oscillation Index (SOI) data. In 12 stations distributed in the province, annual, half-yearly, seasonal and monthly time series were analyzed. The Pettitt-Mann-Whitney, Mann-Whitney-Wilcoxon and Cumulative Sum tests were applied to determine the significance of the detected changes. The result indicates that 1998 and 1995 are the most probable change-point years in the time series of precipitation and temperature, respectively. Compared to the period before 1998 and 1995, annual precipitation and temperature over the province have decreased and increased, respectively. Seasonal precipitation amounts have generally decreased during Autumn, Winter and Spring. In consistence with this finding, the change-point year in SOI time series was found to be the year 1998 that indicates the possible forcing effects of the El Nino-Southern Oscillation (ENSO) phenomenon on the Fars Province climate. Most probably, La Nina phenomenon reduced precipitation in Fars province. However, changes detected in the time series of groundwater level are not consistence with those of climate parameters. It seems that inefficient agriculture sector, mismanagement, over-extraction and thirst for development are main causes for water crisis and the climate change has triggered the crisis.