Melbourne’s average annual rainfall of around 650 mm, concentrated in winter, places a premium on accurate infiltration testing for stormwater management and on-site wastewater systems. The city’s underlying geology — a mix of Quaternary alluvium, basalt flows, and Silurian mudstone — creates highly variable permeability across suburbs, from the sandy soils of the Sandbelt to the clay-rich basaltic plains of the west. Conducting a Porchet or double-ring infiltrometer test at the actual project footprint is the only reliable way to capture the site-specific infiltration rate, rather than relying on regional estimates. Before proceeding with soakage pit design or permeable pavement sizing, our team often complements the infiltration test with a calicatas exploratorias to log soil horizons and a permeabilidad de campo for a broader hydraulic conductivity profile across the property.
A single infiltration test in Melbourne’s basaltic clay can yield rates 10 times lower than a test 50 m away in sandy alluvium — site-specific data is non-negotiable.