Australian Natural Resources Atlas

Rivers - Nutrient Loads and Transport - Queensland

Location Map

Brisbane River Rivers - nutrient loads and transport

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:

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.

Major pools and fluxes

River nutrient loads and 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:

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 Brisbane River

AttributeUnitBasin valueMedian Australia-wide value
Basin areakm213,5727,208
Improved pasture%21
Cropping%10
Horticulture%131
Total agricultural land proportion%167
Climate
Rainmm/y922860
Total evaporationmm/y800584
Runoffmm/y129249

Nutrients delivered to rivers, floodplains, reservoirs and estuaries in Brisbane River

AttributeUnitBasin valueMedian Australia-wide value
Phosphorus from fine sediments%7176
Phosphorus from point sources%250
Phosphorus dissolved from diffuse sources%417
Phosphorus deposited on floodplain%2530
Phosphorus deposited in reservoirs%190
Phosphorus delivered to estuaries%5665
Phosphorus - total basin exporttP/y68546
Phosphorus - export ratekgP/ha/yr10
Phosphorus load - times pre-Europeanratio52
Phosphorus - dissolved to totalratio1721
Nitrogen from sediments%6944
Nitrogen from point sources%150
Nitrogen - dissolved from diffuse sources%1651
Nitrogen deposited on floodplain%1816
Nitrogen deposited in reservoirs%270
Nitrogen denitrified%34
Nitrogen delivered to estuary%5276
Nitrogen - total basin exportt/y3,162451
Nitrogen - export ratekg/ha/y21
Nitrogen load - times pre-Europeanratio32
Nitrogen - dissolved to totalratio3765

Further Information

Key

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