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 Island24.6 ppt22 Jul 14:1556
Bennetts Bay17.3 ppt21 Jul 01:5938
Brooklyn Baths31.0 ppt20 Jul 01:5993
Calabash Bay22.0 ppt22 Jul 13:3031
Courangra Point17.8 ppt22 Jul 14:0063
Crosslands Reserve17.0 ppt22 Jul 06:151
Dangar Island30.0 ppt21 Jul 01:5995
Deadhorse Bay30.8 ppt21 Jul 01:5993
Gosford16.1 deg C (air temp)22 Jul 16:30
Gunyah Point31.4 ppt22 Jul 14:0093
Laughtondale4.8 ppt22 Jul 06:1563
Marramarra Creek7.8 ppt20 Jul 01:5942
Twin Beaches13.6 ppt21 Jul 01:5945
last updated :2017-07-22 16:36

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.