The sediment contribution from estuarine bank erosion is often considered a comparatively minimal component of catchment yields. Yet bank erosion has been a issue in many of our estuaries for over a century, requiring targeted management for bank stability. Bank erosion destabilises estuarine habitats, alters channel morphology, degrades water quality and threatens infrastructure. Often, these threats have been assessed through discrete field inspections and community concerns, but systematic, data-driven analyses remain limited.
Recent whole-of-estuary field-based datasets, coupled with repeat lidar volumetric analyses and bank retreat rates, have been completed throughout NSW estuaries by Fruition Environmental as part of the NSW Estuary Asset Protection Program, managed by NSW DPIRD – Fisheries. Field surveys were conducted to systematically assess the severity and spatial variability of estuarine bank erosion, dominant processes and contributing factors, as well as other key attributes of riparian vegetation and bank protection works.
Repeat lidar data has also been used to quantify sediment yields over the past decade in the Richmond River CMP Stage 2 study. Together these data provide critical insights into estuarine erosion dynamics. Comparisons between field-based assessments and volumetric analyses reveal a coherent alignment, demonstrating substantial localised sediment contributions within our estuaries. Yet key discrepancies in these data highlight the complexity of estuarine hydrodynamics. The assessment also reveals critical limitations and differences in lidar analyses in estuaries compared to freshwater environments.
By integrating these analytical approaches, a more comprehensive understanding of estuarine erosion processes can be achieved, supporting informed management and targeted intervention strategies.