near-term investments, signposts—conditions that would trigger new actions or adjustments—and deferred actions for possible future implementation.

Early applications of these methods to water planning include Robust Decision Making (Groves and Lempert, 2007; Lempert _et al._ , 2003) (RDM) studies in Southern California (Groves _et al._ , 2008, 2014a; Lempert and Groves, 2010) and the U.K. (Dessai and Hulme, 2007). These applications illustrated techniques for generating and evaluating a large ensemble of futures, identifying the key vulnerabilities of current management through a process called “scenario discovery” (Bryant and Lempert, 2010), and then highlighting key trade-offs among the most robust strategies. The Southern California application also introduced rudimentary adaptivity into the robust strategies based on implementing additional management actions if the gap between water demand and available supply grew too small. Recent other applications include two pilot studies for the Water Resources Foundation (Groves _et al._ , 2014b), an evaluation of the Integrated Resources Plan of the Metropolitan Water District of Southern California (Groves _et al._ , 2014a), an application to flood risk mitigation in Vietnam (Lempert _et al._ , 2013a), and for the U.S. Bureau of Reclamation’s Colorado River Basin Study (Bureau of Reclamation, 2012; Groves _et al._ , 2013).

Concurrently, a related methodology has been developed called Adaptation Pathways (Walker _et al._ , 2001), which focuses on defining a comprehensive set of alternative sequences of decisions and identifying the conditions that could guide decision makers along the most appropriate sequence. Haasnoot et al. (2013) demonstrates this approach for flood control in the Netherlands, which includes novel visualizations of different sequences of investments, called “pathways.” Another related methodology, called Decision Scaling (Brown _et al._ , 2012), has been described and applied in the Great Lakes region (Brown _et al._ , 2011) and the Niger River Basin (Brown, 2011). Decision Scaling provides techniques for extensively exploring plausible climate conditions to define the key climate-related thresholds that distinguish different robust strategies.

The World Bank is supporting other projects organized around DMU in several developing countries. These projects range from hydropower investments in Nepal and Africa (Cervigni _et al._ , 2015), urban flood management in Sri Lanka, and transport network’s vulnerability in Peru and Ecuador. A conceptual framework has also recently been developed by the Water Global Practice to guide project planners through the application of DMU techniques to climate change risk assessment and risk management.

These methods recognize the importance of decision maker and stakeholder involvement in the decision analysis. For example, to help SEDAPAL planners gain a deeper appreciation for “deep uncertainty”, the study team facilitated a “serious game” (Mendler de Suarez _et al._ , 2012) called “Decision for the Decade”.<sup>1</sup> The study team then developed participatory, interactive decision support tools to evaluate simulation results and develop portfolios of water management investments. The tools developed are similar to those recently used to support the development of Louisiana’s 2012 Coastal

> 1Information on this “serious game” can be found on the web at: http://www.greengrowthknowledge.org/page/decision-making-under-uncertainty-testing-methodologiesreal-world

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