Year 10: Coastal Management - The Tweed River Entrance Sand Bypassing Project

In your own blog post answer questions 1-9 on pg 167 of your text book.

1. The breakwater on the southern side of the Tweed River acted to trap sand that would naturally be moved in a northerly direction by longshore drift. The continual build‑up of sand on the southern side of the breakwater eventually caused the river mouth to once again silt up. It became apparent that continually extending the breakwaters was not the solution to providing a safe entrance to the Tweed River.
2. In an effort to create a safe river entrance and solve the problem of the beaches immediately north of the

   Tweed being deprived of the natural supply of sand, the accumulating sand at the river mouth was periodically

   dredged and trucked to the Gold Coast where it was used for beach nourishment.
3. During the 1950s the entrance to the Tweed River, which is at the southern end of the Gold Coast, became a hazard to shipping because of sandbars that were forming across the river mouth. This happened because of longshore drift.
4. While these breakwaters initially fixed the problem for shipping, between 1962 and 1965 they had to be extended again due to further sand build-up. At that time the long-term effects on longshore drift and the supply of sand to beaches north of the Tweed River were not considered.
5. Instead of naturally letting the ocean use longshore drift to move the sand, TRESBP pick up the sand in huge quantities and move it themselves, thus stopping the build up of sand and speeding up the process.
6. TRESBP is very effective as a coastal management solution as it stops the build up of hazardous sand to ships and also recycles the sand by adding it to the goldcoast and therefore helping that environment up there. So by helping 2 environments TRESBP is a very effective and useful coastal management scheme but could eventually lead to the destruction of the longshore drift naturally in place.
7. 
   

   
8.  From 1962 onwards the breakwaters have been developed out of the mouth of the river which has stopped the sand coming through with longshore drift, but this has caused the northern beaches to lose sand so it has to be pumped from the south and moved north.
9. 500m