Frequently asked questions (FAQ's)
- Why is the project needed?
- How is the project 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 is happening at Duranbah Beach?
- What will the Southern Gold Coast beaches look like in the future?
- Why will the Southern Gold Coast beaches look more like they did in the 1960s?
- How far along the coastline does the project have an effect?
- Why can't a pipeline be placed that would allow sand to be pumped past Kirra?
- If the Tweed River Entrance is improved, why do entrance boating accidents still occur?
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1. Why is the project needed?
- Prior to the Sand Bypassing Project, the natural northwards movement of sand from NSW to the southern Gold Coast beaches was prevented by the rock training walls at the entrance of the Tweed River. The walls had been extended in the 1960s and had the effect of trapping the sand. This resulted in severe erosion of the southern Gold Coast beaches. Eventually navigation through the Tweed River entrance was also badly affected.
- The Sand Bypassing Project overcame this problem by reinstating the northward movement of sand. This is done by pumping sand that is trapped south of the Tweed River, and discharging it beneath Point Danger, which is at the beginning of the southern Gold Coast beaches. Dredging using a floating dredge is also needed sometimes to clear sand from the Tweed River entrance.
- The benefit to Queensland is that the southern Gold Coast beaches will return generally to the way they were before the Tweed River rock walls were extended in the 1960s. For NSW, navigation through the Tweed River entrance is improved because only a small amount of sand moves into the river entrance.
2. How is the project managed?
- The Project is a joint initiative of the NSW and Queensland Governments. It is administered by the NSW Department of Trade and Investment and the Queensland Department of Environment and Science. The Project also receives funding from City of Gold Coast and the management support of Tweed Shire Council.
3. How often does the system pump sand?
- The sand bypass pumping is a year-round operation to transport the sand that nature brings along the coast. The pumping system usually operates at night but on some occasions there is need to pump in 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 by transporting whatever sand nature brings along the coast to the jetty. Calm conditions usually means 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?
The project is monitored closely by the NSW and Queensland Governments.
- Monthly environmental monitoring summaries are produced for the project area between the Tweed River Entrance in NSW and Kirra in Queensland. Access the most recent summary through our Monthly monitoring summaries page.
- Beach profile surveys are undertaken quarterly between Letitia Spit in NSW and Kirra in Queensland.
- Additional beach profile surveys are undertaken annually out to twenty metres water depth between Fingal in NSW and Currumbin in Queensland.
- Wave conditions are continuously monitored by the Tweed, Gold Coast and Brisbane wave buoys, and this data is available through the Queensland Department of Environment and Science at http://www.qld.gov.au/environment/coasts-waterways/beach/monitoring/
- Aerial photography of the river entrance and the beaches from Fingal to Currumbin is undertaken every six months.
- Beach conditions are monitored continuously by a network of video cameras, and this information is available publicly through our ARGUS beach width monitoring page.
5. Why can't the system stop pumping if people think there is too much sand?
- The Sand Bypassing System re-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 sand nourishment of the Southern Gold Coast beaches that was intended by nature; 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, so this is the amount the system delivers. If a lesser amount were bypassed, 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. Also, the Southern Gold Coast beaches would not receive the sand they require to protect themselves against severe storm erosion for a long time if the sand was not transported to Pt Danger.
- The natural movement of sand northwards is happening day and night. In some northeasterly 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 away by the system or sand will move past the jetty into the river entrance. This limitation on trapping is typical of this type of bypassing system.
6. What is happening at Duranbah Beach?
- Duranbah Beach is affected by the sand bypass project. This is mainly through the maintenance of a deeper river entrance by the project that means not as much sand moves across the entrance to nourish Duranbah Beach. Also the waves that come to Duranbah are changed slightly because there is now no river entrance sand bar. The result of these changes is that the beach is adjusting by moving generally landward as identified in the original environmental impact assessment.
- The project agreement between the governments provides for some 10% of the total sand volume to be discharged at Duranbah. Sand is pumped to Duranbah Beach according to a Duranbah Beach nourishment plan developed in association with Tweed Shire Council. The current approach is to make two sand placements each year (April and November) with allowance for emergency sand placements that may be needed after stormy conditions. While use of certain areas of the beach can be disrupted during placement operations, this approach has maintained reasonable beach amenity and good surfing conditions to date.
7. What will the southern Gold Coast beaches look like in the future?
- When the wide beaches reduce in width, the southern Gold Coast beaches will generally look as they did prior to 1960. It was in the early 1960s that the rock walls at the Tweed River were extended and began to affect the sand supply to the southern Gold Coast beaches.
- Now that the large sand volumes of the first few years are dispersing, the project is now aiming to deliver only the quantities of sand that would have moved naturally. Therefore the beaches will generally cut and build in response to the swell conditions as nature intended.
8. Why will the Southern Gold Coast beaches look more like they did in the 1960s?
- Extension of the Tweed River entrance training walls in the 1960s intercepted the natural northerly drift of sand along the NSW coast causing it to build up to the south of the training walls. This severely reduced the flow of sand to the Southern Gold Coast beaches. The Sand Bypassing System re-instates the natural drift of sand along the coast by trapping it and pumping it to Pt Danger.
- As the Southern Gold Coast beaches will now recieve the natural quantities of sand, these beaches will change and begin to look similar to the way they were before the training walls were extended in the 1960s. This is the reason the Project refers to the pre-1960s as the expected conditions of the beaches in future.
- Once beaches do reach a 'more 1960s' condition, they will still experience natural variations in sand supply, as all beaches do. One special feature of the Southern Gold Coast beaches is that they are subject to 'pulsing' in their sand supply because sand builds up south of Snapper Rocks and moves past Snapper Rocks in 'slugs' in response to episodes of increased southerly swell. This pulsing of sand supply is typical at headlands on the east coast of Australia.
9. How far along the coastline does the project have an effect?
- As at December 2014, the northern limit of beach rebuilding due to sand moved by the project is Tugun and the project has no impacts north of this area at present.
- In the future sand will continue to disperse northwards to replenish the sand losses that have occurred over time along Currumbin beach.
10. Why can't a pipeline be placed that would allow sand to be pumped past Kirra?
The project has the aim of moving sand as nature intended. With the natural flow of sand onto the southern Gold Coast being by sand moving northwards around Snapper Rocks, the project mimics this by discharging sand immediately below Point Danger.
- The concept of a pipeline discharging further north has been raised in community discussion as a way of achieving narrower beaches in the Greenmount to Kirra area more quickly. Such a pipeline would require an elevated, highly visible and very strong structure to be erected on the beach running seawards from near Coolangatta Creek.
- The preparation of designs, planning documents, environmental impact assessments, and community consultation could take several years. Given that Kirra is showing signs of sand volume reduction as expected, by the time a new pipeline could be approved to build, the beach may have narrowed to a more 'natural' profile, and the pipeline would not be needed.
- In the "Kirra Wave Study" – Feb 2007 report prepared for GCCC, the estimated cost of the pipeline was given as $4.5 Million to build plus $0.9 Million per year to operate.
11. If the Tweed River Entrance is improved, why do entrance boating accidents still occur?
- Accidents at the entrance have occurred only very rarely since the Sand Bypassing Project has been operating. This is because the work largely prevents sand from building up into dangerous bars. Before the entrance was improved by the Project, accidents occurred quite regularly and these were often serious.
- 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 make their operations safe by correctly assessing the current and forecast sea conditions and be cautious in making a decision to use the entrance.
Page last updated/reviewed: 23 Mar 2017