Governing distributed urban stormwater systems for catchment-scale outcomes: institutional reforms in Greater Melbourne

Climate change, rapid population growth and urban densification will substantially increase stormwater volumes in Greater Melbourne, with annual runoff projected to rise from about 400 GL to 650 GL by 2050. Yet less than 4% of this resource is currently reused, while pressures on waterways, flood management, urban greening and water supply resilience continue to intensify. This paper argues that addressing these challenges requires a paradigm shift in stormwater management. Although Water Sensitive Urban Design (WSUD) and other nature-based solutions have been widely adopted, implementation has remained largely incremental and project-based, leaving stormwater managed primarily as a drainage by-product rather than as a strategic urban resource. The principal barrier is institutional rather than technological. Stormwater infrastructure is inherently distributed across urban landscapes, but its benefits – improved waterway health, flood mitigation and water supply resilience – depend on coordinated action at catchment and metropolitan scales. Using Greater Melbourne as a case study, the paper identifies the governance, regulatory, investment and institutional reforms needed to enable large-scale stormwater reuse by 2050. It contributes a governance framework for coordinating distributed infrastructure to achieve system-scale outcomes, with lessons applicable to rapidly growing cities facing similar water, climate and urbanisation challenges.