An investigation of the changes in the water table and the storage of western aquifers of Gavkhouni wetland during 1981-2013

In this research, the changes in groundwater table and the volume of water reservoirs of the Kuhpayeh Segzi and southern Mahyar aquifers during the years 1981-1982 to 2012-2013 were investigated. For this purpose, the average level of aquifers' water table was calculated using the Thiessen method. The mean values of the groundwater table obtained from the Kuhpayeh Segzi and southern Mahyar aquifers were recorded as the average level of groundwater table in the Gavkhouni wetland during a 22-years statistical period. Then, changes in the groundwater table and the water volume of Kuhpayeh Segzi and southern Mahyar aquifers, as well as the average changes of the above mentioned parameters were calculated for the wetland area. The trend of groundwater table changes was examined using the Mann-Kendall method. Finally, a hydrodynamic gradient map and field observations were applied to analyze the the interaction of the wetland and its leading aquifers. The results showed that the groundwater table in the Kuhpayeh Segzi and the southern Mahyar aquifers has decreased 2.75m and 12.83 m, respectively and the water volume of the aquifers was reduced by 160 m3 and 300 m3 per year, respectively, until the end of the statistical period studied. The results of Mann-Kendall test also showed a significant decrease in the level of groundwater table in the studied aquifers during the study period. In general, the level of groundwater and the volume of water resources in the wetland area has declined were 7.8 m and 229 million m3, respectively. Also, the results indicated that the Gavkhoni wetland had a nutritional role for the aquifers surrounding during 22 years.