How longshore drift operate and what phenomena affect longshore drift at Muriwai beach:
The fetch of the Muriwai coastal environment is the Tasman sea. The stretch of Tasman sea over the wind blow created the fetch and the strength of the fetch and wind determine the strength of the wave.
Wave approach the beach at an angle due to the direction of the wind.
How we experiment it :
In our group, one person stand on the starting point of another person throwing an orange (and repeat this action for 5 times) to both the Muriwai beach and Maori bay. The movement of the orange help us to determine the direction of the longshore drift which is due to wind. The movement of the wave causes the swash up to the beach and the gravity pulls down the wave.
The orange goes at the direction that cause by the variables that I just mentioned and the data is recorded as below.
Muriwai beach (Longshore Drift)
Distance travelled (m)
Velocity (ms^1)
Direction (N,S,W,E)
Trail 1
60m
0.2ms^1
South
Trail 2
12m
0.04ms^1
South
Trail 3
35m
0.116ms^1
North
Trail 4
89m
0.296ms^1
South
Trail 5
72m
0.240ms^1
North
Average
53.6m
0.178ms^1
South
Maori bay (Longshore Drift)
Distance (m)
Velocity (ms^1)
Direction (N,S,W,E)
Trail 1
13.7m
0.0456ms^1
South
Trail 2
17m
0.056ms^1
North
Trail 3
14m
0.046ms^1
North
Trail 4
3m
0.01ms^1
South
Trail 5
12m
0.04ms^1
South
Average
11.94m
0.0395ms^1
South
Brief conclusion :
The strength and the speed of the drift between Muriwai beach and Maori bay is different. Muriwai beach has a higher strength and also the speed of the drift compare to Maori bay