Climate Changes Effects on Quantity and Quality Conditions of the Bibitalkhone Karstic Spring, Lali Khuzestan

From the past to the present the karstic springs have been taken into account to supply water demands for drinking as well as irrigation, but due to the karstic area characteristics, springs discharges in such horizons are generally impressed by climatic conditions (drought and wet periods), Therefore, recognition of these periods is significant for planning and optimal utilization of water resources. In this study standard precipitation index (SPI), stream flow drought index (SDI) and groundwater resource index (GRI) were computed and compared for a statistical period of 2004 to 2015. The results suggested 2005-2006 as wet, 2013-2014 as drought, and 2015-2016 as a normal years. In order to recognize the effect of the wet and dry periods on spring discharge, the spring discharges and rainfall amounts in these three periods were compared with the average values of these two parameters in the 10 years statistical period. The results indicated that spring discharge in 1384-1385 increased 61% and 54% respectively as compared to the average and normal years. On the contrary, the discharge rate in 2015-2016 decreased 46% and 49% respectively as compared with those of the average and normal years. Therefore, it could be concluded that the Bibitalkhone spring was impressed by precipitation changes in the past. According to water chemistry analysis the EC and TH of the spring water were more than the average in drought period but less than the wet period. The value of these hydrochemical parameters in normal years were close to the average values of ten years. The data also depicted that the chemical quality of spring water was affected by drought and wet periods.