Dredging replenishes Australia’s Sorrento Beach

November 19, 2015 - By GPS World Staff

Shifting sands in Australia’s Port Phillip Bay left a popular beach without enough sand this past holiday season. As summer approached, the Mornington Peninsula Shire and Australian Department of Environment and Primary Industries (DEPI) decided to replenish Sorrento beach by dredging a nearby sandbank.

DEPI awarded the contract to Sandpiper Dredging because of its history of minimizing environmental impact. Sandpiper has a decade of dredging experience and builds its own precision dredgers in Tweed Heads, New South Wales.

Erosion of Sorrento Beach required high-tech repairs. (Photo: Trimble)

The contract specified the dredge ground extent and the minimum Australian Height Datum (AHD) height Sandpiper could dredge. To obtain precise 3D positions from the GPS receiver, GPS corrections were streamed in via cellular Internet from the Victorian government’s Continually Operating Reference System (CORS). Position and heading from the SPS461 receiver were interfaced into construction software to display dredge position. The inclinometer mounted on the dredge frame also interfaced with the software and allowed the AHD height of the cutter head to be displayed.

The dredge position displayed in the software allowed operators to stay within the dredge grounds and ensure no over-dredging occurred. The software was the central hub in the wheelhouse displaying and logging dredge positions and the AHD height of the dredge head.

Machine-control positioning enabled Sandpiper to precisely place in 3D the cutter suction head on the dredge frame in real time. (Photo: Trimble)

The software also allowed the dredge operator to focus on controlling the dredge rather than trying to determine where to dredge. Using GPS and AUSGeoid09 removed the need for considering tide data because the software displayed the AHD height. The logged data could be delivered to the client as an as-built drawing.

The beach was replenished within budget and on time for the holiday season, and the community is now enjoying the restored beach.

Hydrographic Tech

To achieve the job specifications and efficient operation of their dredge, Sandpiper needed hydrographic survey technology on board. SITECH Construction Systems, a Trimble distributor, provided the company with:

Trimble SPS461 GPS heading and positioning receiver
Inclinometer to measure the angle of the cutter head frame
Trimble HYDROpro dredge software to display and log seabed levels. The software can be configured for a wide range of dredgers.

“After speaking about the challenges we had been facing, SITECH came back with the solution of the Trimble HYDROpro system, which meant we could dredge in exactly the right place and maintain coverage, all the while protecting the environment of the beach,” said Daniel Fristch, owner of Sandpiper.