Increasing urban water self-sufficiency: New era, new challenges

This is an excellent paper in the Journal of Environmental Management by Rygaard, Binning, and Albrechtsen - - Increasing urban water self-sufficiency: New era, new challenges.  The record drought of 2012 puts the paper (published in 2011) in the proper context.  The notion of decentralizing and self-sufficiency needs to be considered in a water resource constrained world.  The abstract - -

"Urban water supplies are traditionally based on limited freshwater resources located outside the cities.  However, a range of concepts and techniques to exploit alternative water resources has gained ground as water demands begin to exceed the freshwater available to cities.  Based on 113 cases and 15 in-depth case studies, solutions used to increase water self-sufficiency in urban areas are analyzed.  The main drivers for increased self-sufficiency were identified to be direct and indirect lack of water, constrained infrastructure, high quality water demands and commercial and institutional pressures.  Case studies demonstrate increases in self-sufficiency ratios to as much as 80% with contributions from recycled water, seawater desalination and rainwater collection.  The introduction of alternative water resources raises several challenges: energy requirements vary by more than a factor of ten amongst the alternative techniques, wastewater reclamation can lead to the appearance of trace contaminants in drinking water, and changes to the drinking water system can meet tough resistance from the public.  Public water-supply managers aim to achieve a high level of reliability and stability.  We conclude that despite the challenges, self-sufficiency concepts in combination with conventional water resources are already helping to reach this goal."

Other points in the paper - -

"Self-sufficient water supplies are driven by direct (physical) and indirect (political) water deficits, concerns of water quality, and constrained water infrastructure.  The inter disciplinary nature of the drivers emphasizes that water management is not just an engineering challenge."

And - -

"The desire for self-sufficiency is a major trend and driver for new technologies and concepts in modern water supplies.  Technologies like wastewater reclamation and desalination are attractive because of their reliability and stability, and rainwater collection can decrease pressures on other water resources.  They will become increasingly common as water utilities seek more secure solutions by diversifying their approaches to water supply."