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

1.Why did it become necessary to extend the Tweed River breakwaters? It became necessary to extend the breakwaters because over time sand would build up on the south side of the breakwaters and then silt up the river mouth.
2.What impact would the construction of the breakwaters have had on the replenishment of sand to the Gold Coast beaches after severe storm erosion? The breakwaters would have stopped sand moving to the Gold Coast beaches and so the storm erosion would not be repaired naturally. Instead it has to be dredged and then trucked all the way to those beaches, this costs a lot more than just letting the sand sand get to those beaches through long shore drift.
3.Why did the Tweed River become unsafe to shipping? Explain the natural process that caused sandbars to form over the mouth of the Tweed River The Tweed River became unsafe for shipping because sand kept accumulating at the river mouth. Longshore drift was taking sand up the coast but then it would be stopped at the breakwater and so the sand would just accumulate at that spot. This caused sandbars to form at the river mouth.
4.Why was the dredging of the Tweed River and the associated beach nourishment program only a short term solution to coastal management of the area It was only a short term solution because it was expensive and would need to occur continually and very regularly to make sure the beaches had a sand supply and boats had a safe entrance into the river.
5. Describe the way the TRESBP replaces the natural process of longshore drift The TRESBP pumps the sand from where it has accumulated and sends it to the beaches on the Gold Coast. This replicates longshore drift in that it moves the sand up the coast.
6. Write a paragraph that explains your opinion of the TRESBP. Why do you think the project is regarded as one of the most successful coastal management scheme in Australia? I think the TRESBP is very well done and is doing a great job at making sure the Tweed River doesn't silt up and that the Gold Coast beaches have sand to replenish the beaches. I think that it is one of the most successful because it is doing everything it is supposed to be doing and nothing has gone majorly wrong with the system they have employed.

7. Draw an annotated map to explain the operation of the TRESBP

8. Look at the aerial photographs in 7.28. Describe the changes that have occurred to the mouth of the Tweed River since 1962. The distance the water travels up the beach has stayed the same but the distance up the beach on the right hand side has retreated significantly. 
9. Using the topographic map in 7.25 on on page 164, estimate the length of the breakwater along the Tweed River entrance in 1962 and in 1994. 100m