This preprint is currently under review for the journal HESS.
Landscape scale remediation reduces concentrations of suspended sediment and associated nutrients in alluvial gullies of a Great Barrier Reef catchment: evidence from a novel intensive monitoring approach
Nicholas J. C. Doriean1,2,William W. Bennett1,John R. Spencer2,Alexandra Garzon-Garcia3,Joanne M. Burton3,Peter R. Teasdale4,5,David T. Welsh1,and Andrew P. Brooks2Nicholas J. C. Doriean et al. Nicholas J. C. Doriean1,2,William W. Bennett1,John R. Spencer2,Alexandra Garzon-Garcia3,Joanne M. Burton3,Peter R. Teasdale4,5,David T. Welsh1,and Andrew P. Brooks2
1Environmental Futures Research Institute, School of Environment and Science, Griffith University, Southport, 4215, Queensland, Australia
2Griffith Centre for Coastal Management, Griffith University, Southport, 4215, Queensland, Australia
3Department of Environment and Science, Queensland Government, Brisbane, 4102, Australia
4University of South Australia, UniSA STEM, Scarce Resources and Circular Economy (ScaRCE), SA, 5000, Australia
5University of South Australia, Future Industries Institute, SA, 5000, Australia
1Environmental Futures Research Institute, School of Environment and Science, Griffith University, Southport, 4215, Queensland, Australia
2Griffith Centre for Coastal Management, Griffith University, Southport, 4215, Queensland, Australia
3Department of Environment and Science, Queensland Government, Brisbane, 4102, Australia
4University of South Australia, UniSA STEM, Scarce Resources and Circular Economy (ScaRCE), SA, 5000, Australia
5University of South Australia, Future Industries Institute, SA, 5000, Australia
Received: 05 Jun 2020 – Accepted for review: 22 Jun 2020 – Discussion started: 07 Jul 2020
Abstract. Gully erosion is a major source (~ 40 %) of fine suspended sediment pollution to the Great Barrier Reef. Mitigating this source of erosion will have a lasting positive impact on the water quality of downstream rivers and the receiving marine environment. Here we conduct a preliminary evaluation of the ability of intensive landscape-scale gully remediation to reduce suspended sediment and associated nutrient export from a catchment draining to the Great Barrier Reef. A novel suspended sediment monitoring network, comprised of a suite of new and established automated monitoring methods capable of operating in remote environments, was used to evaluate the water quality of a remediated gully, a control gully and their respective catchments. Suspended sediment concentrations were ~ 80 % lower at the remediated site compared to the control site, indicating the remediation works were successful in stabilising the erosion within the gully. Dissolved and particulate nutrient concentrations were also significantly lower at the remediated site, consistent with the decreased sediment concentrations. The novel combination of suspended sediment measurements from both the gully channels and overland flows in the surrounding gully catchments suggests that sediment and nutrients at the remediated site are likely sourced from erosion processes occurring within the catchment of the gully (at relatively low concentrations). In contrast, the primary source of suspended sediment and associated nutrients at the control site was erosion from within the gully itself. This study demonstrates the potential of landscape-scale remediation as an effective mitigation action for reducing suspended sediment and nutrient export from alluvial gullies. It also provides a useful case study for the monitoring effort required to appropriately assess the effectiveness of this type of erosion control.
Gully erosion is a major contributor to suspended sediment and associated nutrient pollution (e.g., gullies generate ~ 40 % of sediment pollution to the Great Barrier Reef). This study used a new method of monitoring to demonstrate how large-scale earthworks used to remediated large gullies, similar in size and shape to ravines, can drastically improve the water quality of connected waterways. Thus, protecting vulnerable ecosystems, such as coral reefs, from sediment pollution.
Gully erosion is a major contributor to suspended sediment and associated nutrient pollution...
- Printer-friendly version
- Supplement
