Can Groundwater Scenarios Be Predicted from Future Regional Climatic Input Variables?

Conjunctive use of water is an integral part of water resources management. Future groundwater scenarios will dictate the water management policies. The present research focuses on future groundwater scenario generation based on regional scale CMIP5 data. The future scenarios for the years 2030, 2050 and 2080 were generated in terms of the groundwater potential zones (GWPZs) with seven futuristic parameters [land use and land cover, maximum temperature, minimum temperature, rainfall, groundwater recharge, groundwater table and evapotranspiration (ET)]. The Dyna-CLUE and MIROC5 were used for generation of the future change in climate and land use/land cover scenarios. The Soil and Water Assessment Tool (SWAT) was utilized for the recharge and ET estimation. Future groundwater heads were calculated by using the Modular Three-Dimensional Finite-Difference Groundwater Flow (MODFLOW). Bias corrected rainfall and temperature data of Representative Concentration Pathways (RCP 4.5) were utilized. Total twelve water quality parameters (pH, Cl-, Mg2+,F-, Na+, EC, TH, HCO3-, K+, Ca2+, SO(4)(2-)and PO42-) were used for groundwater quality zone (GWQZ) mapping. These GWPZ and GWQZ were divided into three (poor potential, moderate potential, and good potential) and four zones (good quality, moderate quality, poor quality and above permissible limit) respectively. The lower part of the basin was identified as poor GWPZ (35.76% for 2030) and GWQZ due to an increase in urban areas. However, the middle and upstream portion covers good, moderate zones. Field-based soil moisture and groundwater level monitoring data were utilized for validation purposes. It was observed that groundwater level < 5 m bgl corresponds to good GWPZ. It was also observed that recharge and pH were the crucial parameters for good GWPZ (+11.83%) and GWQZ (-21.31%) according to sensitivity analysis.