Blackwood River

Why are material budgets useful?

The availability of light, water and nutrients determines the capacity of land to produce natural vegetation and agricultural yield. In Australia, long-term availability of resources and the consequent potential for generating yield, can be assessed by examining the mass balances of the key resources: water and nutrients (in this case nitrogen and phosphorus). Mass balance gives a quantitative picture of:

• resource inflows or sources;
• resource outflows (including both production outputs and unproductive losses or leakages);
• the resource stock (the amount available for use); and
• the way that the stock changes with time in response to the various inflows and outflows.

The mass balances of water and nutrients are linked by carbon (or biomass) since plant biomass is approximately 50% carbon. Balances and cycles of water, nitrogen, phosphorus and carbon interact and constrain each other.

The figure below provides a schematic of how the couple balances carbon, nutrients and water were constructed and linked to sediment and nutrient transport.

Erosion and sediment transport budgets

The table below presents the key material budget terms modelled or collated as part of the Australian Agriculture Assessment 2001 projects.

The budget terms cover:

• water borne erosion and sediment transport.

Detailed separately are:

• coupled balances of carbon, water, nitrogen and phosphorus; and
• river nutrient transport
  
  Key river basin characteristics such as broad agricultural land use categories and climate are provided for context. All attributes are presented as aggregate mass, rate, ratio or percentage estimate at a river basin scale

Context for understanding the material budgets for Blackwood River

	Why are material budgets useful?
	Erosion and sediment transport budgets
	Context for understanding the material budgets for Blackwood River
	Water borne erosion and sediment transport in Blackwood River
	Further information
Attribute	Unit	Basin value	Median Australia-wide value
Basin area	km2	22565	7208
Improved pasture	%	28.88	1
Cropping	%	22.12	0
Horticulture	%	3.24	1
Total agricultural land proportion	%	54.24	7
Climate
Rain	mm/y	547	860
Total evaporation	mm/y	345	584
Runoff	mm/y	202	249

Water borne erosion and sediment transport in Blackwood River

Attribute	Unit	Basin value	Median Australia-wide value
Sediment supplied to rivers	t/yr	801185	166621
Sediment supply	t/ha/y	.35	.5
Hill slope erosion	%	2.63	14
Streambank erosion	%	27.15	30
Gully erosion	%	70.22	32
Length with riverbed depoistion	proportion	.37	0
Eurpoen to Pre-European sediment	ratio	247	29
Sediment export to coast	t/y	97576	30062
Contribution of sediment to coast	t/ha/y	.04	.1
Sediment delivery	ratio	.12	.34

Further information

View the Australian Agriculture Assessment 2001 report.

View the Water Borne erosion and sediment transport chapter of the Australian Agriculture Assessment 2001 (theme) report.

Technical reports have been prepared by CSIRO Land and Water in the development of this work on water-borne erosion and sediment transport:

• technical report on the " Identification of floodplains and estimation of floodplain flow velocities for sediment transport modelling" by Geoff Pickup and Alan Marks (PDF 0.5 MB)
• technical report on "Gully erosion mapping" by Andrew O. Hughes, Ian P. Prosser, Janelle Stevenson, Anthony Scott, Hua Lu, John Gallant and Chris J. Moran (MS Word 0.6 MB)
• technical report on "Constructing river sediment budgets" by Ian Prosser, Paul Rustomji, Bill Young, Chris Moran and Andrew Hughes (PDF 0.6 MB)
• technical report on " Prediction of sheet and rill erosion over the Australian continent, incorporating monthly soil loss distribution" by Hua Lu, John Gallant, Ian P. Prosser, Chris Moran, Graeme Priestley (PDF 1.7 MB)
• technical report on "Topographic scaling" by John Gallant (MS Word 0.7 MB)
• technical report on "Decomposition of vegetation cover into woody and herbaceous components using AVHRR NDVI time series data" by Hua Lu, Michael R. Raupach and Tim R. McVicar (PDF 1.2 MB)

Link to the Map Maker to make a map using this information.

Link to the Australian Natural Resources Data Library