Newcastle Harbour Entrance Shoal Wave Model and Sand Tracing

An hydraulic model investigation was conducted by the Department of Public Works, N.S.W. to study the problem of increasing the navigable depth across the sand shoal at the entrance to the Port of Newcastle. The model had a moveable bed and generated waves and tidal currents. For verification and correct operation of the model it was necessary to assess the direction and quantity of littoral drift at the entrance to Newcastle Harbour. To do this, sand tracing using radioactive and fluorescent sand, was conducted. It was found that sand moves in a northerly direction past the entrance. Several proposals involving extensions to the existing breakwaters were investigated. None of these indicated a significant and consistent improvement in depths over a 500 feet wide channel along the existing harbour leads, and all would require maintenance dredging. One proposal which would eliminate the need for dredging was the construction of a new breakwater out from Stockton Beach, however this was not economically feasible. The most feasible solution was to dredge a deeper channel through the shoal, which could then be maintained with a minimal amount of dredging. This proposal was adopted and has proved highly successful.