Testing the resilience of water supply systems to long droughts

Abstract

The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. Public water supply systems are designed to maintain water supply through 21 extended periods of dry weather without excessive cost or environmental 22 damage. During a drought, water suppliers can take further measures to 23 enhance supplies or reduce demand. The introduction of drought measures is 24 usually formalised in a drought plan, but there is often little evidence that the 25 plan will prove successful during a range of feasible droughts. As the climate 26 changes, recent hydrological data may be a poor guide to future drought, and 27 planned actions may prove insufficient to maintain adequate water supplies. 28 29 This paper describes a method for testing the resilience of water company 30 drought plans to droughts that are outside recent hydrological experience. 31Long severe droughts of the nineteenth century provide an opportunity to test 32 water supply system behaviour in a range of realistic droughts. The method 33 developed combines system modelling with an interactive approach that asks 34 water system managers to work through the actions that they would take at 35 different stages of the drought, without knowledge of subsequent drought 36 development. 37 38The approach was tested for two contrasting English water resource systems. 39In both cases, the existing water supply and drought planning measures 40 succeeded in maintaining water supply, but significant demand restrictions 41 and engineering measures had to be introduced. Wider use of the method by 42 water supply planners should allow the refinement of drought and water 43 supply plans, and will also create increased awareness of the actions 44 necessary to manage a range of droughts.

Drought in a human-modified world: reframing drought definitions, understanding, and analysis approaches

“…Like some global and lumped hydrological models mentioned before, many water management models are capable of simulating the effect of the allocation of water on hydrological processes also during drought, as was shown by Querner et al (2008) and Van Oel et al (2012), or simulating the influence of water management decisions on the evolution of a given drought scenario (e.g. Watts et al, 2012).…”

Dealing with Uncertainties in Fresh Water Supply: Experiences in the Netherlands

“…We believe that a robust system, that can deal well with frequent as well as rare events, will also be able to deal well with changed variability under a future climate (Watts et al 2012). Knowledge or assumptions about the future climate variability are not needed to perform robustness analysis.…”

Developing system robustness analysis for drought risk management: an application on a water supply reservoir

“…Such drought plan development can be supported by "stress-testing" water supply systems on drought events that are more severe and/or longer in duration than historic droughts (e.g., Watts et al, 2012;Steinschneider and Brown, 2013). However, decision making criteria are lacking to compare and rank various drought management measures.…”

“…The concept of robustness originates from the engineering literature, where it is defined as the ability of systems to maintain desired system characteristics when subjected to disturbances (Carlson and Doyle, 2002). A similar concept, resilience, originates from the socioecological resilience community and is defined as the ability of ecosystems or socio-ecological systems to absorb disturbances without shifting into a different regime (Holling, 1973;Walker and Salt, 2006;Folke, 2006;Scheffer et al, 2001). Robustness and socio-ecological resilience are comparable concepts (Anderies et al, 2004), but robustness is considered more suitable for systems in which some components are designed ).…”