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Water Quality

The Darling River:Algal growth and the cycling and sources of nutrients

Project M386 1999

A key aim of the project was to identify environmental conditions responsible for the occurrence of blooms of blue-green algae (cyanobacteria) in the Darling River. Emphasis was given to describing the role of phosphorus and identifying its major sources of supply. Specifically we sought to:

  • develop an empirical model of phytoplankton growth
  • identify the main environmental conditions that trigger blooms of cyanobacteria
  • identify the amounts and the physico-chemical forms of nutrients transported in the river
  • determine the factors that control ė bioavailabilityî (ie. availability to phytoplankton) of the various forms of major nutrients
  • assess whether the present phosphorus concentrations in the river are higher than they were before European settlement
  • identify and quantify the major sources and types of phosphorus reaching the Darling River
The influence of riverine conditions on the growth of phytoplakton was investigated in a section of the Darling River near the township of Bourke. Sediment transport was investigated from samples of suspended particles and bottom sediments collected from sites distributed along the length of the river. Catchment sources of particles were investigated using soil samples collected from transects of 100km length distributed across different land types.

Download a copy of Project M386 Report 1999

        Full Document             Project M386 Report 1999 [PDF 4.8Mb]

Cover pages  [PDF 37 KB]
Executive Summary  [PDF 140 KB]
Contents  [PDF 135 KB]
Chapter 1. Introduction to the study   [PDF 264 KB]
Chapter 2. Characteristics of the darling river environment   [PDF 398 KB]
Chapter 3. Effects Of Flow On Thermal Stratification And Phytoplankton Growth   [PDF 758 KB]
Chapter 4. Turbidity, Conductivity, Light Penetration And Phytoplankton Growth   [PDF 397 KB]
Chapter 5. The Effects Of Saline Groundwater Intrusion On Water Clarity And The Riverine Environment   [PDF 324 KB]
Chapter 6. Nutrient Availability And Phytoplankton Growth   [PDF 361 KB]
Chapter 7. Interactions Between Phosphorus And Suspended And Bottom Sediments, And The Fate Of Phosphorus Released From A Sewage Treatment Plant   [PDF 284 KB]
Chapter 8. The Flow Regime Of The Darling-Barwon River And Its Tributaries, With Implications For Understanding Sediment Transport   [PDF 324 KB]
Chapter 9. Major Element Chemistry Of Sediments From The Darling Barwon River And Its Tributaries: Implications For Sediment And Phosphorus Sources   [PDF 417 KB]
Chapter 10. The Contribution Of Different Erosion Sources To The Fine Grained Sediment In The Darling-Barwon River System   [PDF 335 KB]
Chapter 11. Concluding Discussion And Management Implications   [PDF 206 KB]
References  [PDF 223 KB]
Appendix A   [PDF 185 KB]

The results of the project demonstrate the hierarchical and complex interplay of factors that influence water quality and lead to the development of phytoplankton blooms in the Darling River. The project has described key processes responsible for the degradation of water quality and identified where management efforts need to be focussed to improve conditions. It is hoped that further studies will build on this research as we struggle to maintain our river systems into the future.

Date content was posted : 04/06/2004

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