Scope and limitations of drought management within complex human–natural systems

Abstract

Growing evidence suggests that drought risk is increasing due to climate change. Evaluation of potential policy responses involves understanding complex economic tradeoffs, hydrologic and social feedbacks, and recognizing how combinations of interventions may have complementary or conflicting effects. This paper explores the potential that coupled human–natural system models have to address these questions. We employ a detailed model of the Willamette River Basin, Oregon, to evaluate the effectiveness of a variety of potential drought policy interventions to conserve or reallocate water during a simulated near-term drought year. The drought year is characterized by early-season low flows that make it impossible to meet water demands. The results indicate that while the policies are effective at conserving water, they have limited ability to mitigate the shortages because the timing and location of conservation responses do not match the timing and location of the shortages. The growing prevalence of drought conditions across the world means that mitigation and adaptation will require accounting for feedback loops between water availability and interventions. The Willamette River Valley in Oregon serves as a case study for how to use coupled human–natural systems to mitigate drought.