Public Access Status:
The Sand Bypass System jetty is currently:
Open between 8 am and 8 pm
about The Sand Bypass System
The unique and innovative system consists of a steel framed jetty, constructed 500 metres out to sea and 250 metres south of the southern training wall. Ten jet pumps, suspended from the jetty at 30 metre intervals from the seaward end, are submerged to 11 metres below mean sea level.
The Sand Bypass System jetty operates when sand builds up. When not in operation, access to the jetty is now free for the public between the hours of 8am to 8pm, we asked that the community uses the jetty safely and keeps the space clean and tidy for others.
To reduce the burden on the electricity network, operation is planned for nights and weekends when community demand for electricity is low, however on occasion, weather conditions may mean that sand needs to be pumped during the day.
How does it work?
Water to operate the sand bypass system is taken from Marine Stadium via twin low pressure, high volume turbine pumps to the control building where a high pressure centrifugal pump boosts the water pressure to that required for activation of the jet pumps. Sand on the seabed in the vicinity of the operating pumps is forced into the system in a water/sand mix and returned to the shore through the gravity fed flume. Here it is discharged into a conical shaped concrete hopper where excess water is decanted back to the ocean while concentrated sand slurry is pumped by a variable speed centrifugal pump through an underground pipeline, under the seaway entrance to discharge onto the southern ocean beach on South Stradbroke Island.
The system may be operated with a varying number of selected jet pumps to give optimum performance. Computer control and monitoring ensures maximum economy and efficiency of the operation. Pumping operations are normally conducted at night during off-peak power periods.
In June 2019, we installed a pilot solar array to help meet the operation’s day-time energy needs. Read more about our solar power here.
Why is it necessary?
The Southport Bar was incredibly dangerous until 1986 when the Gold Coast Seaway was opened. Predominant southeasterly winds, the significant northern drift of sand and wave climate combined to move an estimated 500,000 cubic metres of sand along the south-east Queensland coast each year. Over time the Nerang River mouth moved northward by up to 60 metres each year, causing land erosion and changing sandbanks at the bar and adjoining Broadwater. The sand bypass system was provided for in the design of the Gold Coast Seaway as it was recognised that the breakwaters would not be effective for long without a solution to the littoral drift problem. The large-capacity fixed-sand bypassing system is an integral part of the design of the seaway.
Benefits of the Sand ByPass System
The system currently delivers 500,000 cubic metres of sand from the spit to South Stradbroke Island each year. Today, the Gold Coast Seaway facilitates safe transit between the Broadwater and the ocean for recreational and commercial vessels. An improvement in water quality due to increased tidal exchange has enhanced biodiversity in the Broadwater. The Broadwater also has a greater capacity for flood relief. The construction of the sand bypass system, dredging and construction of Wave Break Island have ensured that the entrance to the Broadwater was stabilised without detriment to surrounding beaches.
Want more info? Check out our Sand Bypass System Brochure.
THE SAND BYPASS SYSTEM
The Sand Bypass System is an engineering masterpiece that ensures the Gold Coast community can enjoy safe entry from the Broadwater to the Pacific Ocean all year round. The jetty is a working structure that intercepts the natural northward drift of sand from the south, stops it entering the Broadwater and deposits it on South Stradbroke Island. A Backpass Project is currently underway that will use the intercepted sand to replenish the beach at Surfers Paradise.
Last updated: 30 July 2021