Discover Your Local Waterways

Wherever you live in Hornsby Shire, you are part of a stormwater catchment — and your everyday actions play a key role in the health of our local waterways. A catchment is simply the area of land where rainwater flows across the surface and collects at the lowest point, often in dams, creeks, rivers or estuaries.

Most of Hornsby Shire’s catchments drain into the lower Hawkesbury River estuary. However, in the southern part of the Shire — generally south of Pennant Hills Road — stormwater flows instead into the Lane Cove River and eventually into Sydney Harbour. This is the only area within Hornsby where water runs to the Harbour rather than to the Hawkesbury.

When it rains, water runs off our roofs, gardens, roads and footpaths, carrying stormwater via the stormwater drainage system into nearby creeks and rivers. This water continues downstream into our estuaries. Because estuaries sit at the bottom of a catchment, they are especially vulnerable to pollution and changes upstream. A healthy estuary is essential for both nature and people — supporting recreational activities like swimming, fishing and boating, as well as industries such as oyster farming and commercial fishing.

Some parts of our catchments remain in a natural state, while others have been heavily modified. In urbanised areas, natural creek lines have often been replaced by concrete stormwater channels to manage flooding. These changes have significantly impacted the health and function of our waterways.

Hornsby Shire is fortunate to have vast areas of bushland, wetlands and creeks that provide vital ecological, recreational, economic and social benefits. By understanding and caring for our local waterways, we help preserve this unique environment for future generations.