Tide measurements at Fort Denison began in 1857, using a benchmark cut into the stonework of the Martello Tower. Since 1867, surveyors have upgraded instruments to incorporate advancements in measuring technology.
For over 150 years, the Port Authority survey team has maintained and calibrated the Fort Denison tide gauge, ensuring its accuracy and reliability. The site holds historical significance within NSW, especially with the recent installation of a CORS NSW GPS beacon nearby.
The World Meteorological Organization (WMO) awarded the Fort Denison tide gauge centennial status, recognising its global importance as a long-term tide monitoring site where surveyors have consistently recorded data in the same location for over a century.
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Commercial survey services
Our Survey Services Team is frequently contracted for hydrographic surveys along the coastal waters of NSW
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Our Geographic Information System (GIS)
History of tides in Sydney Harbour
Tide measurements at Fort Denison began in 1857