“…A variety of integrated modeling approaches have shown promise for estimating water scarcity by attempting to capture the complex interactions between water and the economy, drawing on multiple disciplines and applying the tools of benefit-cost analysis [Draper et al, 2003;Brouwer and Hokfes, 2008;PulidoVelazquez et al, 2008;Ward, 2012]. Efforts of this kind have contributed to our understanding of water scarcity in settings ranging from agriculture [Cai et al, 2003a[Cai et al, , 2003b, to the protection of habitat for endangered species [McCarl et al, 1999], to the effects of biofuel production [de Moraes et al, 2012], to optimal management of groundwater pollution [Pena-Haro et al, 2011], to tradeoff between irrigation and endangered species protection under drought [Ward et al, 2006a[Ward et al, , 2006b], and to potential impacts of climate change and water management [Hurd and Coonrod, 2012;Varela-Ortega et al, 2012]. One approach, ''holistic water resources-economic optimization modeling,'' seeks a greater degree of integration of both hydrologic and economic systems so that a more consistent, endogenous treatment of the coupled human-natural interrelationships is achieved [Cai, 2008].…”