An Agent-Based Modeling Approach to Simulate the Performance of Hybrid Water Systems and Rainwater Micro-Trading

As climate change and population growth exert more pressure on urban water systems, new water management strategies are needed. Water micro-trading is a novel economic strategy that aims to reduce urban water demand. In micro-trading, a household acts as a prosumer and collects surplus rainwater through rainwater harvesting. Prosumer households can trade rainwater with another consumer household that exerts an outdoor water demand. The traded water is transferred via an underground aquifer without the need for additional citywide infrastructure. New research is needed to quantify the effect of micro-trading on urban water supply and water table height. This research uses a data set from Perth, Australia, which contains 30-min water demand data for 36 households that use a variety of sources including rainwater and mains water, which is water provided through centralized drinking water infrastructure. These households are modeled as agents in an agent-based model (ABM). Agent actions include harvesting rainwater, trading water, and using water. The ABM is simulated to generate water consumption and groundwater contributions over a nine-month period. Water trading results are used as input to a groundwater model developed with MODFLOW to assess the effects on groundwater tables and sustainability. Preliminary results indicate that roughly 8% of consumer outdoor water demand can be offset using traded water. Research results will evaluate the impacts on water tables in the Greater Perth area. Results of this study demonstrate the effectiveness of micro-trading as a new water saving strategy.