Many construction teams in Melbourne assume topsoil loss is only a landscaping concern, then watch cut slopes unravel after the first heavy autumn rain. Without quantifying erodibility parameters such as dispersion ratio, shear strength of the surface layer and particle detachment thresholds, temporary batters fail and sediment loads exceed EPA Victoria guidelines. We integrate field infiltration tests with calicatas exploratorias to visualise soil layering, then run laboratory dispersion tests on the same samples. This dual approach captures both surface runoff behaviour and sub-surface seepage paths, giving engineers the data needed to design effective sediment basins and stabilisation measures before earthworks begin.
A standard soil erodibility test can reduce sediment basin sizing by 25% when the actual K-factor is half the tabulated value.