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The sustainability of water resources depends on the dynamic interactions among the environmental, technological, and social characteristics of the water system and local population. These interactions can cause supply-demand imbalances at diverse temporal scales, and the response of consumers to water use regulations impacts future water availability. This research develops a dynamic modeling approach to simulate supply-demand dynamics using an agent-based modeling framework that couple models of consumers and utility managers with water system models. Households are represented as agents, and their water use behaviors are represented as rules. A water utility manager agent enacts water use restrictions, based on fluctuations in the reservoir water storage. Water balance in a reservoir is simulated, and multiple climate scenarios are used to test the sensitivity of water availability to changes in streamflow, precipitation, and temperature. The framework is applied to the water supply system in Raleigh, North Carolina to assess sustainability of drought management plans. Model accuracy is assessed using statistical metrics, and sustainability is calculated for a projected period as the satisfaction or deficit of meeting municipal demands. Multiple climate change scenarios are created by perturbing average monthly values of historical inflow, precipitation, and evapotranspiration data. Results demonstrate the use of the agent-based modeling approach to project the effectiveness of management policies and recommend drought policies for improving the sustainability of urban water resources.

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Abstract. In the event that a bacteriological or chemical toxin is introduced to a water distribution network, a large population of consumers may become exposed to the contaminant. A contamination event may be poorly predictable dynamic process due to the interactions of consumers and utility managers during an event. Consumers that become aware of a threat may select protective actions that change their water demands from typical demand patterns, and new hydraulic conditions can arise that differ from conditions that are predicted when demands are considered as exogenous inputs. Consequently, the movement of the contaminant plume in the pipe network may shift from its expected trajectory. A sociotechnical model is developed here to integrate agent-based models of consumers with an engineering water distribution system model and capture the dynamics between consumer behaviors and the water distribution system for predicting contaminant transport and public exposure. Consumers are simulated as agents with behaviors defined for water use activities, mobility, word-of-mouth communication, and demand reduction, based on a set of rules representing an agents autonomy and reaction to health impacts, the environment, and the actions of other agents. As consumers decrease their water use, the demand exerted on the water distribution system is updated; as the flow directions and volumes shift in response, the location of the contaminant plume is updated and the amount of contaminant consumed by each agent is calculated. The framework is tested through simulating realistic contamination scenarios for a virtual city and water distribution system.

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