GIS-based multi-criteria decision analysis using AHP and Fuzzy-AHP for identifying potential rainwater harvesting zones in lower Shivaliks of Punjab (India)
摘要
In the present era, climate change coupled with population explosion, industrial advancement and upsurge in agricultural activities has put a tremendous pressure on freshwater resources leading to water crisis. To manage this ongoing issue, rainwater harvesting (RWH) at potential sites is emerging as an ecofriendly strategy for sufficing the agricultural and other domestic requirements. In this perspective, it is imperative to identify the potential sites for harvesting the excess rainwater which otherwise flows as a surface runoff. In the present study, suitable sites for rainwater harvesting have been identified in block Balachaur of District SBS Nagar Punjab (India) using GIS and multi-criteria decision-making techniques. The analytical hierarchy process (AHP) and Fuzzy-AHP techniques have been used in GIS environment to identify the most suitable sites for RWH. This study advances current GIS-based rainwater harvesting (RWH) assessment approaches by integrating both AHP and Fuzzy-AHP within a multi-criteria geospatial decision framework. Eight criterion layers including runoff depth, soil type, slope, stream order, drainage density, geology, LULC and distance to roads have been used. AHP and Fuzzy-AHP have been used to assign the weight to each layer and then weighted overlay analysis (for AHP) and fuzzy overlay (for Fuzzy-AHP) was done in ArcGIS to generate the RWH site suitability maps. The AHP-based RWH site suitability map revealed that about 7.34% (23.04 km2) of the total area is extremely suitable for RWH. About 33.69% (105.78 km2) and 38.29% (120.23 km2) is highly and moderately suitable for RWH, respectively. Similarly, Fuzzy-AHP-based map showed that around 13.10% (41.13 km2) of the area is extremely suitable for RWH in the study area. Similarly, the area under highly suitable and moderately suitable is 29.43% (92.41 km2) and 36.82% (115.61 km2), respectively. The area under less suitable category is almost as AHP analysis (20.65%; 65.0 km2). The validation of developed map has been done by obtaining the ground truth points of various RWH structures and by using the ROC-AUC technique. The ROC-AUC of 0.89 for AHP and 0.90 for Fuzzy-AHP indicates very good predictive accuracy rate. The comparative evaluation of AHP- and F-AHP–derived suitability maps provides new scientific insights on how deterministic and fuzzy decision structures influence RWH zone delineation. The findings of the present study shall be beneficial for policy makers including soil conservation officers and other line departments to implement proper rainwater harvesting measures in the study area.