Beach monitoring and evaluation

The traditional way of measuring sand levels on beaches is called a 'beach profile'. A beach profile is a measurement taken at the intersection of a beach's ground surface with a vertical plane perpendicular to the shoreline.

Since the mid 1970s, a network of beach profiles has been established along the South Australian coast at places where beach erosion could cause problems for public property and development. The profile lines are regularly surveyed and evaluated for long-term changes in sand levels.

Today, other methods are used to monitor beaches as well. Brass rods installed in the seabed along the Adelaide coast are used to measure depth changes from sand movements. Seabed deepening is a particular issue along the Adelaide coast due to the loss of seagrass.

A surface modelling technique is also employed along the coast to map and measure large sand movements due to replenishment projects or erosion. This technique involves covering the study area with a grid of surface points and then using surface modelling software to create a surface model. When models surveyed at different times are different, the changes can be mapped and volumes calculated.

Where cliff erosion is an issue, a row of spikes located behind a cliff top at set distances are used to measure the cliff top offset. Over time cliff top erosion rates can be determined by this method.

Aerial photography also provides a valuable tool for measuring coastal change. DENR has a comprehensive collection of aerial photography taken at different times allowing comparisons to be made between different photos and the differences mapped.

More information 

Refer to our reference material page.