Developing an approach to evaluate the effectiveness of investments in riparian management in the GBR catchments
Led by: Dr Rebecca Bartley, CSIRO
The current tools used to estimate the contribution of bank erosion to the Great Barrier Reef (i.e. Source Catchments model), are based on empirical relationships using little or no data from tropical river systems. This project proposes to develop a revised methodology for estimating (a) the natural or bench-mark rates of bank erosion in tropical rivers (b) how this information can be coupled with improved data sets on channel morphology, site connectivity and sediment particle size to develop a more robust approach for identifying sites amendable to remediation and (c) where riparian restoration has occurred, evaluate the effectiveness of the remediation.
Streambank erosion is estimated to contribute ~30-40% to end of catchment sediment yields in the Great Barrier Reef (GBR) catchments. However, our understanding of the degree of alteration of bank erosion with the introduction of agriculture, and the success of methods for remediating bank erosion sites (using approaches such as riparian vegetation, fencing and stock removal), is limited. Without a robust understanding of these issues it is difficult to target sites for remediation as well as to evaluate the costs and benefits of undertaking remediation in the riparian zone.
How Research Addresses Problem
Risk frameworks, previously known as A,B,C,D frameworks, are used to evaluate the influence of improved grazing land management on hillslopes in rangelands, and for nitrogen use in sugarcane. No such risk framework exists for riparian management. Before such a framework can be developed, we need an improved understanding of the rates of bank erosion and channel change we can expect in natural or well managed landscapes. Without such information we don’t know what we are trying to restore bank erosion rates to, and if the remediation actions being implemented (e.g. fencing) will be effective at reducing sediment delivery from bank erosion.
Bank erosion; Sediment; Particulate nutrients; Remediation; Vegetation.
This project is jointly funded through CSIRO, UQ, DSITIA and the Australian Government’s National Environmental Science Programme.