Assessment of agricultural land suitability for irrigation with reclaimed water using geospatial multi-criteria decision analysis

摘要

Water scarcity, climate variability and continuing growth in water demand have put severe pressure on high-quality freshwater sources. This challenge exacts the necessity to explore alternative water sources for agricultural irrigation. The objective of this study was to implement the integrated geospatial Multi-Criteria Decision Analysis (MCDA) with the Analytical Hierarchy Process (AHP) to evaluate the potentiality of reclaimed water use for agricultural irrigation in California. Five evaluation criteria included in this study were agricultural land (crop type), climate conditions, water policies, irrigation status, and proximity to wastewater treatment plants (WWTPs) respectively. The suitability maps for reclaimed water use were generated for three cases in terms of accessibility to WWTPs, their discharge volume and appropriate treatment processes respectively. In addition, a composite suitability map was produced using the hybrid model considering all three cases together. Results from this study led to a better understanding of sustainable reclaimed water use for crop irrigation at a regional level. It provided supporting evidence of the applicability of the GIS-MCDA method integrated with AHP technique for a larger geographical scale with a diverse crop pattern. This study established the importance of using both knowledge-based and data-driven criteria and sub-criteria in the decision framework. The results also highlighted how the spatial distribution of suitable areas for reclaimed water reuse is closely linked to the agricultural areas.