Proceedings of the 2015 Winter Simulation Conference L. Yilmaz, W. K. V. Chan, I. Moon, T. M. K. Roeder, C. Macal, and M. D. Rossetti, eds. SIMULATING REGIONAL HYDROLOGY AND WATER MANAGEMENT: AN INTEGRATED AGENT-BASED APPROACH John T. Murphy Jonathan Ozik Nicholson Collier Argonne National Laboratory and University of Chicago, Computation Institute 5735 S Ellis Ave Chicago, IL 60637, USA Mark Altaweel University College London 31-34 Gordon Square London, WC1H 0PY, UK Richard B. Lammers Alexander A. Prusevich University of New Hampshire Institute for the Study of Earth, Oceans, and Space, 8 College Road, Durham, NH 03824, USA Andrew Kliskey Lilian Alessa University of Idaho 709 S. Deakin Street, Moscow, ID 83844, USA ABSTRACT Water management is crucial to all societies. In addition to the technical challenges of moving large volumes of water from often distant sources to the populations that use them, water management entails a social challenge as well. In this paper we present a linked simulation framework in which a large-scale hydrological Water Balance Model (WBM) is linked to an Agent-Based Model (ABM) in which agents represent urban water managers. We present a test case in which agents plan individual water schedules to meet their consumers’ needs, and optionally can interact when scheduled amounts fall short of actual demand. The simulation framework allows us to examine the impact of these relationships on the larger hydrology of the region, under different policy structures and water stress. We present a case study based on water management in Phoenix, Arizona, along the Central Arizona Project (CAP) canal. 1 INTRODUCTION Water is crucial to life and central to human activities. As individuals we must consume water to survive, and collectively we use water for agriculture, energy, industry, transportation, and many other purposes. Human societies have managed water since their beginnings, and while modern societies have advanced technology with which to move and use water, the centrality of water, and – increasingly, in many areas – its scarcity, make water management more than a technical challenge: it is equally a social challenge. The southwestern United States is an area in which water management has been achieved technologically through extensive infrastructure investment; this has reached extraordinary scales, as water is diverted and moved across large states and throughout the region. Equally impressive is the social infrastructure: the complex collection of laws, rights, and economic components that regulate who gets water, when, and for what purposes. This social picture is difficult to understand, but crucial to manage: cooperation and conflict among different parties who must share water as a resource can shape 3913 978-1-4673-9743-8/15/$31.00 ©2015 IEEE