Tweed River Entrance Sand Bypass Project (TRESBP)
The Tweed River entrance is located on the southeast coast of Australia, just south of the border between the states of New South Wales (NSW) and Queensland. Training walls were constructed in the late 1800's on both sides of the entrance to improve navigation. The walls were extended in 1962-64. Unfortunately, the walls starved the downdrift beaches and nearshore shoals of sand and the bar across the entrance returned over time despite the works (Jackson, 1985; Jackson, 1989; Jackson & Tomlinson, 1990). More Details
The need for restoration of the nearshore shoals off the southern Gold Coast beaches was recognised in the early 1980's by Angus Jackson (Special Projects Engineer - Gold Coast City Council). After protracted negotiations by Gold Coast City Council with the NSW and Queensland state governments, the Tweed River Entrance Sand Bypassing Project (TRESBP) was established in the late 1990's by governments from both states with Gold Coast and Tweed Shire Councils (Jackson et al., 1989), aiming to:
- Establish and maintain a clear navigation channel
- Supply sand to the southern Gold Coast Beaches at a rate consistent with natural littoral drift, in addition to that required to restore the beach's recreational amenity.
This has been achieved using a combination of sand bypassing by a permanent sand pumping jetty (commissioned and operated by McConnell Dowell) and regular maintenance dredging of the entrance (undertaken by McQuade Marine).
International Coastal Management has been involved in implementation of this project through the management of dredging operations (McQuade, Jackson & Corbett, 2001). As the Tweed River entrance is in an area with high wave energy, tidal flows and longshore transport (averaging 500,000m3/yr), conditions are difficult for dredging, particularly in the vicinity of the rock training walls. The dynamic environment, combined in the later stages with the interaction with the bypassing system, has led to the need for a higher awareness and responsiveness to coastal processes than more typical, straightforward dredging. As such, the dredging has been aimed at efficiently achieving and maintaining the objectives as quickly as possible, rather than just moving sand from the dredge area to the deposition area. More Details
The deposition of sand into the nearshore zone to restore the eroded shoals has had a beneficial impact on surfing, providing up to over a 1km ride. Numerous stories have been published in the international surfing magazines such as 'Surfer' (July 2003) and 'SurfEurope' (Oct 2003).