7.6 The Tweed River Entrance Sand Bypassing Project

1. It became necessary to extend the breakwaters because the sand from the adjacent beaches was pouring into the river channel, which was making it extremely unsafe for boats and other watercraft to navigate the river entrance.

2. It would have a positive and negative effect. The beaches south of the breakwaters would benefit from the breakwater extending out into the ocean because the sand would build up against it, which would strengthen the sand amount on the beach, but the northern beaches would not benefit at all because of the breakwater. The breakwater would obstruct the sand from reaching the northern beaches and they would have a lot less sand than the southern beaches.

3. The Tweed river became unsafe to shipping because of the sand bars that were forming in the river entrance. This made it unsafe to ships to pass through here because they ran the risk of running aground or piercing their hulls.Longshore Drift is the natural process responsible for this, as the sand was pushing north and forming in the mouth of the river.

4. The dredging of the river was only a shot term solution because mainly the cost. Over the next 25 years it will cost over $50 Million to dredge regularly and the breakwaters should do a good job of keeping the sand out of the river, which will eliminate the need for dredging, or at least decrease the cost of it significantly.

5. The TRESBP Project replaces the natural process of Longshore Drift because it is an obstruction to the natural processes of Longshore Drift. The two breakwaters do not allow the water to travel along the coast, so sand will build up against the southern breakwater and at the northern end of the beach above the northern breakwater.

6. I believe that the Tweed River Entrance Sand Bypassing Project was a very good idea and it has been extremely successful, leading to it being one of the most successful coastal management strategies in Australia. I think that excellent planning has gone into the project which has prevented sand building up into the Tweed River Entrance and along with the dredging in the mouth of the river, the process of Longshore Drift has been disrupted in the entrance of the river and this has allowed it to now be safe for marine craft to navigate the entrance and the bar of the river.

7.

 

 8. Since 1962, the distance the water has traveled up the beach is the same, however the distance up the beach on the right side has changed significantly.

9. The length of the breakwater was 100m.