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 Island30.2 ppt24 Sep 22:1573
Bennetts Bay19.6 ppt20 Sep 23:5942
Brooklyn Baths34.3 ppt20 Sep 23:5996
Calabash Bay27.4 ppt24 Sep 21:3043
Courangra Point24.0 ppt24 Sep 22:0081
Crosslands Reserve21.3 ppt24 Sep 06:151
Dangar Island34.2 ppt20 Sep 23:5997
Deadhorse Bay33.1 ppt20 Sep 23:5996
Gosford17.1 deg C (air temp)24 Sep 23:30
Gunyah Point34.8 ppt24 Sep 22:0096
Laughtondale10.0 ppt24 Sep 22:1581
Marramarra Creek8.3 ppt20 Sep 23:5942
Twin Beaches14.8 ppt20 Sep 23:5946
last updated :2017-09-24 23:36

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.