Erosion Soil Sampling for Streambank Stability

by Emily Wilson, Project Officer – Waterways

Earlier this month, my colleague Kelsey Marek and I assisted with erosion soil sampling at a streambank site along the O’Connell River. This is one of the erosion sites we are hoping to remediate as part of Reef Trust’s Landscape Repair Program.

Due to the steepness of the bank, Reef Catchments engaged a local drilling contractor to collect samples from the surface down to a depth of 6m – which helped avoid safety risks and spared us from the usual dirt-covered venture of a typical soil sampling day.

Analysing the soil allows us to assess erosion risk by calculating dry bulk density and the proportion of fine sediment particles (like silt and clay), which contribute to sediment runoff into the Great Barrier Reef.  This information helps us estimate sediment yields, and design targeted, cost effective erosion control treatments.

Back in the office, we took over the hallway to lay out the full 6m of soil samples – fortunately it was a quiet day in the office! Laying out the samples, we examined the different soil layers, noting changes in colour, texture, structure, moisture and strength before sending them off to a lab for analysis.

Seeing the full 6m profile laid out was a great reminder of how much variability exists below the surface and just how quickly soil characteristics can change from one layer to the next. Using erosion soil sampling to understand the soil helps us design more effective erosion control solutions, helping farmers protect valuable agricultural land, and reducing sediment runoff into waterways and the Great Barrier Reef, which impacts reef resilience and biodiversity.

The Waterways team is dedicated to working with landholders to achieve big outcomes within the waterways space.

See more information on projects being carried our by our Waterways team.