Identification of Suitable Structures for Rainwater Harvesting and Natural Aquifer Recharge in a Mountainous Basin using GIS-based Multi-Criteria Analysis

Abstract

A healthy ecosystem that supports all living forms depends on water, which is the most magnificent natural resource. Considering the acute global water scarcity, it is critical to investigate rainwater gathering techniques that incorporate practical drought mitigation strategies. In addition to providing a selection of the best sites for natural aquifer recharge, the ultimate objective of this work is to determine where rainwater harvesting structures can be built for efficient and successful rainwater harvesting management in the research region. The current work also focuses on identifying possible locations for natural aquifer recharging utilizing RS and GIS methodologies because the water table is rapidly declining. Land use/land cover, slope, soil, runoff, drainage density, and road limitations were the five criteria used to identify RWH locations using GIS-based MCEs. Using the soil and water assessment tool approach, the observed runoff depth varied from 0 to 900 CMS, and the RWH unit's appropriateness ranged from highly suitable to least suitable. The Panjkora River Basin's total area of 1128.395 km² is the most suitable for building farm ponds, whereas 954.756 km² is moderately suitable. The suitable area for check dam building is 350.58 km², while the moderate area is 245.31 km². According to the results, 1572.518 km² are the most suitable areas to build gully plug structures in order to prevent soil erosion and store rainwater, while 3742.38 km² are of moderate appropriateness. In the current study seven local influencing factors, e.g., land use and land cover (LULC), drainage density, slope, population density, water table, elevation, and soil types, were used to accomplish the objective of natural aquifer recharge sites. More than 72% of the basin has been classified as having moderate to very high potential for artificial recharge. The land area is categorized as highly suitable in 30.19% of cases and very high suitability in 1.01% of situations. In terms of hydrology, this spatial correlation is quite important. Highly or very highly suitable locations for recharge are found in many sections of the moderate and poor groundwater zones. Particularly in areas where traditional groundwater extraction is no longer technically or economically feasible, these interventions would encourage vertical infiltration, lessen runoff, and aid in the restoration of dwindling aquifers. Water managers can implement location-specific, data-driven methods to increase climate resilience and long-term water security in the Panjkora Basin by coordinating recharge planning with natural recharge potential and current groundwater stress.