An Alternative Approach to a Achieve Water Resiliency

Abstract

This case study of Auckland, New Zealand, examines an alternative method of water supply. Centralized water utility networks supply the majority of water to all municipal sectors. Increased population and an outdated and failing distribution system mean water shortages and restrictions are becoming more frequent occurrences for the cities around the world. The uncertainty of water resiliency must be brought into question regarding the future supply of water for Aucklander’s who are becoming increasingly subject to restrictions placed on water use. This study looks at rainwater harvesting as an alternative method of water supply to the failing centralized system. Water supply, obtained from flow data provided by the utility, indicate seasonal water use patterns. GIS analysis of each distribution zone in Auckland provides a clear analysis of each structure’s roof area. Runoff Data compiled from 70,834 structures suggests that runoff from precipitation events would be sufficient to fully replace centralized supply in months of higher rainfall. Partial offsets of ≥ 75% were also simulated in 5 of the 7 distribution zones studied. The correlation between roof area + runoff produced and water supplied from the utility is also examined to determine the best zone for implementing this alternative approach.