An Empirically-based sediment budget for the Normanby Basin: Sediment Sources, Sinks & Drivers on the Cape York Savannah

admin-cywq — Mon, 02 Jan 2023 06:26:34 +0000

An Empirically-based sediment budget for the Normanby Basin: Sediment Sources, Sinks & Drivers on the Cape York Savannah admin-cywq Mon, 01/02/2023 - 16:26

ABSTRACT

This project report contributes to the Australian Government’s Reef Rescue program. The project scope included development of a new empirically driven sediment budget model, incorporating improved understanding of water quality management, and undertaking on-ground rehabilitation research. These activities are combined to address the following core questions:

What is the proportional contribution of suspended sediment from eastern Cape York rivers to the GBR lagoon compared with the rest of the GBR catchments?
To what extent are the contemporary sediment loads from this area elevated above pre-European levels?
Which sub-catchments or stream segments are disproportionately contributing to the total sediment load?
Of the current key sediment sources, which ones are elevated as a result of land-use intensification, and can anything be done to practically reduce the supply of sediment from these sources?

This document describes the development of an empirically driven sediment budget for the catchments draining to Princess Charlotte Bay (PCB). This includes the Laura/Normanby/Kennedy Rivers, the North Kennedy, Hann, Annie Rivers, Saltwater Creek and Stewart River. This budget identifies the major sediment sources, erosion processes, sediment stores and transport pathways for the suspended sediment component of the sediment budget at the catchment scale (i.e. end of system loads). The existing Brodie et al. (2003) sediment budget formulation effectively acted as a hypothesis to guide our data collection.

ABOUT THE DOCUMENT

This report is set out as an extended Executive Summary (62pp, main document) that references 17 supporting Appendices.

The Appendices are styled according to their intended final audience (eg, some of the papers are pre-formatted for journal publication). Each Appendix is also date-stamped. If you receive a copy from a colleague or other source, you can compare dates. The latest version is always available from this website (except where publisher rights prohibit it).

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Citation

Brooks AP, Spencer J, Olley J, Pietsch T, Borombovits D, Curwen G, Shellberg JG. An Empirically-based sediment budget for the Normanby Basin: Sediment Sources, Sinks & Drivers on the Cape York Savannah. (Howley CM, Gleeson AL, Simon A, Bankhead N, Klimetz D, Eslami-Endargoli L, Bouregault A). Brisbane, Queensland Australia: Australian Rivers Institute, Griffith University; 2013 p. 572.

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sediment_budget_brooks_etal_2013_0.pdf (9.34 MB)

DocName

Executive Summary and overview (62pp)

Type of Resource

Primary Report

Alluvial Gully Prevention and Rehabilitation Options for Reducing Sediment Loads in the Normanby Catchment and Northern Australia

admin-cywq — Sun, 01 Jan 2023 21:58:03 +0000

Alluvial Gully Prevention and Rehabilitation Options for Reducing Sediment Loads in the Normanby Catchment and Northern Australia admin-cywq Mon, 01/02/2023 - 07:58

This is the final report from a two-year project funded by the Australian Government’s Caring for our Country Reef Rescue Initiative was undertaken by Griffith University to assess the options for preventing and rehabilitating alluvial gullies in the Normanby Catchment, with implications for alluvial gully management across northern Australia. Alluvial gullies eroding into terraces and elevated floodplains along river frontage with dispersible or sodic soils are a major sediment source in the Normanby catchment and northern Australia. Traditional Owners, cattle graziers and other local residents in the catchment and along Princess Charlotte Bay are concerned about economic, cultural and environmental impacts of local gully erosion and downstream sedimentation. Large alluvial gullies – and gullies in general – are often considered to be in the ‘too hard basket’ for basic land management action. However, large reductions in elevated sediment loads at the catchment scale will not be achieved unless gully erosion is addressed cumulatively through innovative proactive land management actions.

The aims of this report were to: 1) review the current scientific knowledge on alluvial gully erosion in northern Australia, 2) review scientific and grey literature on gully prevention, rehabilitation, and best management practice options applicable to alluvial gullies, 3) implement several field trials for preventing and rehabilitating alluvial gullies, and 4) provide information toward the future development of a comprehensive regional Best Management Practice (BMP) manual to address alluvial gully erosion based on scientific principles and proven field success. Social, economic, and political obstacles to cumulatively reducing gully erosion and sediment yield at the catchment scale are also reviewed.

While this report does not provide detailed BMP solutions for all gully erosion issues in the Normanby catchment or elsewhere, it does highlight in detail the nature of the problem and potential research and management actions for the future. Reducing sediment loads to river systems and coastal environments will not occur unless these cumulative and complex physical, chemical, biological processes and social, economic, and political management issues are understood and addressed.

Citation

Shellberg JG, Brooks AP. Alluvial Gully Prevention and Rehabilitation Options for Reducing Sediment Loads in the Normanby Catchment and Northern Australia Griffith University. Prepared by Griffith University, Australian Rivers Institute; Prepared for the Australian Government Caring for Our Country Reef Rescue Program; 2013.

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shellberg_normanby_gully_exec.pdf (2.12 MB)

DocName

Alluvial Gully Prevention and Rehabilitation: Exec Summary

shellberg_normanby_gully_report_0.pdf (19.3 MB)

DocName

Alluvial Gully Prevention and Rehabilitation: Full Report

Type of Resource

Primary Report