Hawkesbury Monitoring

HawkesburyWatch is a near real-time rainfall, water level and water quality monitoring system which provides information to Hornsby Council and the public of NSW. This management system has been developed by MHL for Hornsby Council to provide maps of Salinity, Temperature and Swimming Conditions in the lower Hawkesbury river. For further information visit hornsby.nsw.gov.au.

Swimming Conditions

Pollution is likely Swim at own risk Pollution unlikely

Swimming SiteSalinity
Parts per 1000
Latest dataStatus% 'Pollution unlikely'
in the last 12 months
Bar Island10.4 ppt27 Mar 06:1560
Bennetts Bay1.9 ppt25 Mar 01:5952
Brooklyn Baths16.6 ppt25 Mar 01:5991
Calabash Bay2.9 ppt26 Mar 05:4549
Courangra Point1.1 ppt27 Mar 06:0062
Crosslands Reserve1.0 ppt27 Mar 06:152
Dangar Island17.9 ppt25 Mar 01:5994
Deadhorse Bay15.8 ppt25 Mar 01:5992
Gosford21.4 deg C (air temp)27 Mar 11:00
Gunyah Point26.7 ppt27 Mar 06:0093
Laughtondale1.0 ppt27 Mar 06:1563
Marramarra Creek1.4 ppt25 Mar 01:5957
Twin Beaches2.2 ppt25 Mar 01:5960
last updated :2017-03-27 11:21

Salinity data has been used to predict the likelihood of bacterial contamination at swimming sites in the Hawkesbury. The occurrence of freshwater in the estuary following rainfall increases the likelihood of pollution being present. Obvious signs of stormwater pollution are water discoloration as well as debris in the water and tide line. When pollution is likely, swimmers may be at increased risk of contracting illness and swimming at these times should be avoided.

This system utilises recorded data captured by MHL on behalf of HSC and a 3D hydrodynamic model configured by Office of Environment and Heritage for HSC of the Hawkesbury-Nepean estuary. Model input data is sourced from various agencies including Bureau of Meteorology, MHL, SCA, OEH and Dept of Primary Industries Office of Water.
Data is downloaded at 2am each morning and the model is run based on the previous days monitored data. The results will show interpolated contour maps based on the previous day.