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 Island28.8 ppt28 May 22:1551
Bennetts Bay18.9 ppt27 May 01:5939
Brooklyn Baths30.5 ppt23 May 01:5990
Calabash Bay23.1 ppt28 May 21:4532
Courangra Point23.4 ppt28 May 22:0055
Crosslands Reserve13.9 ppt28 May 06:151
Dangar Island32.8 ppt27 May 01:5993
Deadhorse Bay32.1 ppt27 May 01:5991
Gosford16.5 deg C (air temp)29 May 02:00
Gunyah Point33.9 ppt28 May 22:0091
Laughtondale7.8 ppt28 May 22:1556
Marramarra Creek8.4 ppt27 May 01:5943
Twin Beaches14.8 ppt27 May 01:5946
last updated :2017-05-29 02:21

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.