Water quality monitoring in the Swan River. Photo by K Trayler/DBCA
Water quality monitoring in the Swan River. Photo by K Trayler/DBCA

Your portal to information on the river

Water quality monitoring occurs on a weekly basis in the Swan Canning Estuary and fortnightly in its catchment.

Sampling informs understandings of:

  • hydrodynamic conditions within the waterway
  • microalgae activity 
  • estuarine and catchment water quality

Microalgae Activity 

A weekly Microalgae Activity Report (MAR) is prepared to inform the public on microalgae activity levels, the probability of discoloration and/or scum formation, and potential warnings. This is based on data collected at 20 routine monitoring sites throughout the Swan Canning river system.

Concentrations of chlorophyll-a, a plant pigment, are used to estimate microalgal activity. This is presented by the use of low, medium and high activity categories. An alert category may be used where an algal species occurs at concentrations that may be harmful to aquatic life or human health and requires public advice.


  Low Medium High Alert
  Low levels of microalgae with no likely visible impact Possibility of discolouration and/or scum formation High probability of discolouration and/or scum formation Presence of species potentially harmful to aquatic life, OR human health requiring public advice
Chlorophyll-a (µg/L) < 4 4 - 10 > 10 N/A

This week's Microalgae Activity Report

Week starting: Monday 27th June 2022 (next update scheduled for 7th July 2022)

  • Microalgae activity was low to medium throughout the Swan Canning Rivepark this week.
  • Help keep our rivers healthy by maintaining your boat and prevent oils, fuels and cleaning chemicals from entering the water.
  • Discarded fishing line kills wildlife – please take all line and tackle home or use bins provided.

See the map below to view this week's microalgae activity levels. Select the map icons for more information. Trouble viewing the map below? View in a new window.

MAR alert levels

Estuarine and catchment water quality

Data collected from monitoring in the Swan Canning Estuary and its catchment is compiled into annual reports to inform management. More information on monitoring, evaluation and reporting of the estuarine condition is available on the Parks and Wildlife Service website.

Hydrodynamic conditions

Extensive water quality monitoring is conducted in the Swan River from Fremantle to West Swan, and the Canning River from Mount Pleasant to Langford. Parameters measured include salinity, oxygen content and water temperature.

Water quality profile reports are prepared weekly to convey information on the prevailing conditions within the waterway. Recent reports are available for download at the bottom of this page. Older reports are available on the Parks and Wildlife Service website for the Swan River and the Canning River.



Page reviewed 01 Jul 2022