A hybrid MCDA approach for delineating sites suitable for artificial groundwater recharge using drywells

Artificial recharge in urban aquifers is of vital importance due to the increase in urbanization resulting in a reduction in natural recharge along with groundwater overdraft in many regions across the globe. Despite existing several managed aquifer recharge (MAR) technologies, land availability for installation and limited municipal budget restrict their usage, especially in urbanized areas. Hence, drywells were introduced as a vadose zone recharge (VZR) facilitating the recharge of stressed aquifers with low land impact and financial resources. Also, identifying suitable sites for drywell implementation is complex due to the number of driving factors involved. In this paper, the integrated fuzzy analytical hierarchy process (FAHP) and technique for order of preference by similarity to ideal solution (TOPSIS) approach was proposed to delineate a site suitability map for artificial groundwater recharge using drywells in the city of Kayseri, Turkey. Nine decision criteria were selected and the weights of each (sub-) criterion were determined through the FAHP. The results indicated that hydraulic conductivity, depth to groundwater, soil texture, and land use/land cover were the most determining criteria with 33.9%, 17.8%, 11.2%, and 10.1% of weights, respectively. Also, the stability and robustness of the criteria weights attained were validated through sensitivity analysis within the FAHP framework. Finally, the study area was divided into 54 sub-regions based on the road-network and the TOPSIS was applied to prioritize the sub-regions to help identify promising areas for the vadose zone wells construction. Here, a similar approach can be adopted by municipalities lacking guidelines and standards for sitting drywells.