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 Island23.9 ppt24 Jun 22:1552
Bennetts Bay15.0 ppt23 Jun 01:5937
Brooklyn Baths28.6 ppt21 Jun 01:5993
Calabash Bay18.6 ppt24 Jun 13:4531
Courangra Point23.7 ppt24 Jun 22:0058
Crosslands Reserve11.3 ppt24 Jun 06:151
Dangar Island29.5 ppt23 Jun 01:5995
Deadhorse Bay29.8 ppt23 Jun 01:5993
Gosford13.8 deg C (air temp)25 Jun 02:30
Gunyah Point33.4 ppt24 Jun 22:0093
Laughtondale1.8 ppt24 Jun 14:1558
Marramarra Creek7.1 ppt21 Jun 01:5942
Twin Beaches12.3 ppt23 Jun 01:5945
last updated :2017-06-25 02:51

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.