Eutrophication (phosphorus)

Eutrophication (phosphorus)

Eutrophication of the wheatbelt’s natural waterways is a problem related to excess nutrients and sediments entering from modified agricultural landscapes. High concentrations of nutrients encourage algal growth and result in harmful blooms. By retaining nutrients and sediments through good land management and farm practices in the catchment, we can reduce the amount entering waterways and abate the eutrophication process.

How can we monitor progress?

At Wheatbelt NRM Inc. we have searched for data that can help us monitor the status of nutrients in our waterways. At a catchment scale we can report on the nitrogen and phosphorous load of major rivers in the region. At a local level we can follow the water quality of surface waters at discrete locations and track the amount of fertiliser applied in the region by primary producers.

Phosphorus leaving the Avon River

Total phosphorous levels leaving the Avon River measured at the Great Northern Highway (Site Ref: 616076) between 1994-2021 plotted against the threshold of potential concern (TPC).

Source: Department of Water and Environmental Regulation


Fertiliser use in the catchment

The average rate of nitrogen and phosphorous application across the region in 2020. 

Source: Planfarm Bankwest Benchmarks 2013/14 – 2020

Explore nutrient and sediment loads in the region

Click here to view the full map

Click on the “Nutrient loads” layer to see modelled catchment nutrient loads (Source: WA Department of Water), actual nutrient loads measured in the Avon River at Millendon (Source: Swan River Trust) and a snapshot of Avon River pool conditions (Source: WA Department of Water).

Click on the “Sedimentation” layer to see potential sediment contribution from sub-catchments in the zone of rejuvenated drainage.


Department of Water and Environmental Regulation

Australian Bureau of Statistics LaMPS data

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