When Urban Stormwater Meets High Groundwater – Part 1

In Perth, Western Australia, “high” groundwater areas (i.e. where the groundwater is less than 4 m below ground) represent an important challenge for residents, real estate developers and public authorities. High groundwater is an indispensable resource supporting wetlands and vegetation. Yet current knowledge and management practices are lagging in their ability to maintain the benefits to hydrologic and ecologic systems, while reducing risks to urban infrastructure and open space. An Expert Panel was convened by the Cooperative Research Centre for Water Sensitive Cities (CRCWSC) in 2019-2020 to gain a better understanding of current practices for monitoring, modelling, and managing groundwater levels in urbanising sites. The study consisted of a literature review, followed by site inspections and in-depth interviews with water industry professionals from local government authorities, consulting firms, state government departments, and researchers based in Western Australia. Consultation was also undertaken with four urban development/water industry representative groups. The recommendations resulting from the investigation include a three-tier risk hierarchy indicating minimum modelling requirements for low-, medium- and high- risk sites. Improved groundwater management practices in Western Australia could not only mitigate impacts on public and private property but could also serve as guidance to other areas across the world, from Seattle to Taipei, where development of high groundwater areas entails similar challenges and opportunities.