Scenario development for water resources planning and watershed management: Methodology and semi-arid region case study

Utilizing the scenario development framework from Mahmoud et al. (2009), a set of scenarios were developed for and applied in the Verde River Watershed in Arizona, USA. Through a scenario definition exercise, three dimensions of future change with respective axis extremes were identified: climate change (periodic droughts vs. sustained drought), demographics (water-conservative population vs. water-consumptive population), and the economy (booming economy vs. poor economy). In addition to the various combinations of dimension extremes, each scenario was given a unique event or theme that was characteristic of the combination of dimension extremes it possessed. The scenarios were then fleshed out into narrative forms that expanded on the details of each scenario’s internal temporal evolution. The scenarios were analyzed by a water supply and demand model that was specifically constructed for their simulation. Following the analysis of scenario results, assessment narratives were provided to outline the impact of each scenario on the Verde River Watershed and management operations in that basin.

► Eight scenarios were developed for the Verde River Watershed.
► The scenarios were simulated using a simplified water supply/demand model.
► Scenario impacts were assessed with respect to surface and ground water supplies.
► Current water usage in the basin is not feasible for long term sustainability.