Abstract: A Scalable Vector Graphics (SVG) simulation tool has been developed for the optimal management and risk assessment of urban stormwater harvesting systems. The aim is to create a tool to model the Helps Road Drain in the City of Salisbury, South Australia. The system consists of a stormwater supply channel with an urban catchment and a series of 5 inline storage facilities, each serving to capture and hold stormwater for harvesting and aquifer recharge and also as a temporary water storage for flood mitigation. The purpose of the simulation tool is to analyse the operations of urban stormwater harvesting systems and to study the movement of water through a series of connected dams in conjunction with an aquifer storage and recovery (ASR) system. The simulation tool will provide water managers with an easy-to-use computer-based management package. The system will generate simulated rainfall scenarios and associated simulated runoff to enable a realistic assessment of system capacity and performance and will allow managers to visualise limiting factors and assist in understanding the interdependence of different system components. The simulation tool has the ability to investigate the effectiveness of various water management policies by evaluating the Conditional Value-at-Risk (CVaR) for failure of the stormwater supply system. The tool provides visual outputs of simulated situations and information about simulated statistics and observed distributions of the movement of water.