Evaluation of climate and land-use variables on groundwater recharge of Lenjanat region using WEAP-ANFIS

The formulation of strategies for sustainable groundwater resources needs an integrated view of land-use, climate changes, social system, and the response of the hydrological system. Negligence in creating a balance between these variables in charging and discharging groundwater resources has led to problems such as land subsidence, saline water advancement, reduced water quality, increased pumping costs, etc. in most of the country aquifers. In this study, the Lenjanat region was selected as a case study and one of the important regions of the Zayandehrud Watershed due to its interaction with the river, the existence of land-use changes, and increasing harvest from the regional aquifer. The results of temperature and precipitation prediction in an optimistic and pessimistic scenario until 2035 by the LARS Model and the results of examining past and future land-use changes and calculating the impact factor (adjustment coefficient) using IDRISI SELVA, ENVI, and CA-Markov were included in the study model (a combination of WEAP and ANFIS) to investigate future runoff and its contribution to aquifer recharge. The results showed that both climate and land-use changes have some impacts on water resources. In the case study, the amount of runoff decreases due to the decrease in rainfall and increase in temperature, and runoff infiltration, and subsequent feeding and groundwater level decrease due to land-use changes and increase in groundwater abstraction. The average rainfall volume was estimated at 194.17 million cubic meters in the observed years, of which 99 million cubic meters rechrged the aquifer. The average volume of groundwater supply after the effect of an adjustment coefficient of 1.051 was predicted in the optimistic scenario of 10.09 and the pessimistic scenario of 93.72 million cubic meters, respectively.