Frequently asked questions (FAQ's)
- Why is Tweed Sand Bypassing needed?
- How is Tweed Sand Bypassing managed?
- How often does the system pump sand?
- What environmental monitoring is undertaken on a regular basis?
- Why can't the system stop pumping if people think that there is too much sand?
- What happens at Duranbah Beach?
- What has happened to Letitia Spit?
- How far along the coastline does Tweed Sand Bypassing have an effect?
- If the Tweed River entrance is improved, why do entrance boating accidents still occur?
If you have any other specific questions that you would like to be answered or added to this list please contact us.
1. Why is Tweed Sand Bypassing needed?
- Before the Tweed Sand Bypassing (TSB) Project started, the natural northwards movement of sand from New South Wales (NSW) to the southern Gold Coast beaches was prevented by the rock training walls at the entrance of the Tweed River. The walls were extended in the 1960s and had the effect of trapping the naturally migrating sand. This resulted in severe erosion of the southern Gold Coast beaches. Although the extension of the training walls improved navigation through the Tweed River entrance for a limited period, the trapped sand eventually built up to the point that the river entrance was again obstructed and navigation was badly affected.
- The Tweed Sand Bypassing Project has overcome this problem by reinstating the northward movement of sand and maintaining a navigable entrance to the Tweed River. This is done by pumping sand that is trapped south of the Tweed River by the training walls and discharging it beneath Point Danger, which is at the beginning of the southern Gold Coast beaches. Dredging using a floating dredge vessel is also used to clear sand from the Tweed River entrance when necessary.
2. How is Tweed Sand Bypassing managed?
- Tweed Sand Bypassing (TSB) is a joint initiative of the NSW and Queensland (Qld) Governments. It is administered by selected Departments in each State Government in accordance with the relevant legislation and delegated authorities. The Project also receives support and funding from City of Gold Coast (CoGC) and the management support of Tweed Shire Council (TSC).
3. How often does the system pump sand?
- Sand bypass pumping is a continuing operation to transport the sand that nature brings along the coast. The pumping system usually operates at night but on some occasions needs to pump during the day. There is no 'down period' or 'pumping season' in the operation.
- One of the characteristics of the pumping system is that it is designed to replicate nature as far as possible, by transporting whatever sand nature brings along the coast to the jetty. Calm conditions usually mean little or no sand to pump, while in higher wave conditions pumping may be continuous, when there is a lot of sand moving along the coast.
4. What environmental monitoring is undertaken on a regular basis?
TSB is monitored closely by the NSW and Qld Governments and is independently audited on a regular basis.
- Monthly environmental monitoring summaries are produced for the project area between the Tweed River Entrance in NSW and Kirra in Qld. Access the most recent summary through our Monthly monitoring summaries.
- Beach profile surveys are undertaken quarterly between Letitia Spit in NSW and Kirra in Qld.
- Additional beach profile surveys are undertaken annually out to twenty metres water depth between Fingal in NSW and Currumbin in Qld.
- Wave conditions are continuously monitored by the Tweed, Gold Coast and Brisbane wave buoys, and this data is available through the Qld Department of Environment and Science.
- Aerial photography of the river entrance and the beaches from Fingal to Currumbin is undertaken every six to twelve months.
- Beach conditions are monitored continuously by a network of cameras, and this information is available publicly through the Tweed Sand Bypassing coastal imaging page.
- Additional coastal imaging resources.
5. Why can't the system stop pumping if people think there is too much sand?
- The Sand Bypassing system connects the southern Gold Coast beaches to the natural drift of sand that moves north along the NSW coast and would otherwise be obstructed by the Tweed River entrance training walls. It does this for two main reasons:
- to provide the natural sand nourishment of the southern Gold Coast beaches that would occur if the Tweed River entrance training walls had not been constructed/extended; and
- to keep sand from drifting into the Tweed River entrance and affecting navigation by boats.
- The rate of sand delivery by the system mimics the estimated rate of natural sand transport at the time of pumping. Natural sand transport rates fluctuate seasonally and on a day-to-day basis. Sometimes nature supplies more than an average amount of sand, which is then bypassed by the system. If the system did not keep up with natural sand supply, sand would move past the jetty and enter the river channel. This would make access by boats into and out of the river entrance more dangerous. Additionally, the southern Gold Coast beaches would not receive the sand they require to provide protection against severe storm erosion if the sand was not transported by the Project.
- The natural movement of sand northwards is happening day and night. In some north-easterly wave conditions sand may move southwards briefly, but the dominant direction of sand movement is northwards.
- The system has no ability to store sand or delay its delivery. It has a relatively small trap under the jetty formed by pumps that are located 12 to 15 m below the water surface. So, if nature brings sand into the jetty area, it has to be transported by the system or it will move past the jetty into the river entrance. This limitation on trapping sand is typical of this type of bypassing system.
6. What happens at Duranbah Beach?
- Duranbah Beach is located just north of the Tweed River entrance. It is famous with surfers for its consistency of surf quality. To a large degree, the quality of waves at Duranbah Beach is determined by the off shore sand delta in front of the Tweed River entrance. It is this delta that interacts with swell and provides the peaky wave conditions that Duranbah is known for. When pumping to the main system outlet of Snapper Rocks East, Duranbah Beach is skipped by the sand bypassing project. To maintain an adequate amount of sand at Duranbah Beach, sand is delivered (usually) one to two times per year to the upper beach. To do this a temporary pipe is set up and sand is strategically placed.
7. What has happened to Letitia Spit?
- With the extension of the Tweed River entrance training walls in the 1960s, sand accumulated south of the southern training wall and Letitia Spit grew in width. This was due to the southern training wall trapping the natural flow of sand that had previously flowed through to the southern Gold Coast beaches.
- With the commencement and continuing operation of the sand bypassing project restoring the natural northerly flow of sand, Letitia Spit retreated and is now in a similar position to what it was prior to extension of the training walls.
8. How far along the coastline does Tweed Sand Bypassing have an effect?
- The legislated project boundary extends from approximately 2 km south of the southern training wall of the Tweed River entrance, through to about Lang St at north Kirra. Although this is where the most notable effects of the project can be seen, monitoring of beach conditions occurs from Fingal Head through to Currumbin.
9. If the Tweed River entrance is improved, why do entrance boating accidents still occur?
- Entrance accidents will still happen from time-to-time. However it must be remembered that the conditions of the sea at the entrance are not only determined by entrance depth and offshore wave conditions, but also the weather and river tidal flow, especially at times of strong outgoing tides. Skippers must always undertake their operations safely by correctly assessing the current and forecast sea conditions and be cautious in making a decision to use the entrance.