Identifying managed aquifer recharge and rain water harvesting sites and structures for storing non-conventional water using GIS-based multi-criteria decision analysis approach

In arid climates, conventional water resources are severely limited and stressed in the face of rapid population growth and
future climate change. So, it is necessary to find alternative non-conventional water resources for use in drought situations.
Additionally, the non-conventional water resources in these areas are not sufficient to meet future water demand. Therefore,
non-conventional water resources can be adopted as a strategic reserve to bridge the gap between water supply and demand
in case of emergency and drought events. These resources might include rainwater harvesting, treated wastewater, and
desalinated seawater. Managed aquifer recharge (MAR) can be applied to store these resources in the hydrogeological system
using Geo information System—Multi Criteria Decision Analysis (GIS-MCDA) approach for determining the suitable MAR
location for storage. North-west Kingdom of Saudi Arabia area was chosen for this study because it is extremely arid, has
high potential for social and economic development, and it has newly constructed non-conventional water infrastructures
distributed throughout the area including water desalination plants, Tertiary Sewage Effluent (TSE) waste water plants, and
flash-flood storage dams. To identify the suitable MAR site location and structure, different data related to aquifer hydrogeology,
surface hydrology, hydrometeorology, and water quality were applied. Then, GIS-MCDA holistic approach was
applied with aid of ordered weighting average (OWA) technique. Finally, two maps were created to show the MAR location
and structure type. Potential map indicates that ~ 18.85% of the area is suitable for MAR installations. About 0.17% of the
total area exhibited very high potential, where infiltration ponds can be applied, 1.86% had high potential for construction
of check dams with diversion channels, and 16.82% had moderate potential for installation of recharge wells. Additionally,
56 MAR structures were proposed and a map showing their locations has been created. Thus, results indicated that the study
area is promising for MAR installation. These maps could aid the decision makers to propose a sustainable development
plan for the future water resources of the area.