Coastal Managment Geography Report

Narrabeen is a beachside suburb located on Sydney’s northern beaches with a population of just over 6000 people. It is known for its long stretch of beach, over 3 kilometres, with four beaches on this stretch: North Narrabeen, Narrabeen, South Narrabeen and Collaroy. The Narrabeen coastal environment consists of these beaches as well as the lagoon located at the north end of the beach. Surrounding areas are on a floodplain, meaning that high sea levels, large amounts of rain and runoff from nearby hills and mountains can lead to flooding occurring.

Hydrological process operating within the Narrabeen Coastal environment
The hydrosphere refers to the interconnected system of water storage in the atmosphere and lithosphere, including the oceans, ice caps, rivers and groundwater. Narrabeen is a beachside suburb and is highly influenced by the hydrosphere. Processes involved in the hydrosphere are water, salinity, temperature, waves, tides and current. Longshore drift is a major process operating within the Narrabeen coastal environment. Longshore drift involves the transport of sediments along a beach, controlled mainly by waves, tides and currents.

At Narrabeen, the sediment is moved northwards towards the lagoon entrance. When large amounts of sediment drifts to the lagoon entrance, blockages occur. These blockages prevent water from entering or leaving the lagoon as the sand bar is higher than the water levels. Poor water quality can be a result of these blockages as run off from housing pollutes the water in the lagoon and if it can't wash out to see due to the block, the quality for the water drops. Another problems as a result of the closed entrance is flooding. Flooding occurs when the closed entrance prevents water from flowing out to sea and with high amounts of rain, the local area will flood due to it being a floodplain and being very flat. In photo 1.1, longshore drifts transfers sediment towards the bottom of the image, which is the northern part