2.2.2. Treatment 2: wave barrier and silt trap fence
A 1.5–2.0 m height silt trap fence (Fig. 4b) was set up inside the
wave barrier fence (use constructed in treatment 1), approximately
20–25 m offshore from the dyke. The silt trap fence had one row of
Melaleuca (pole 4; Table 1) sunk 2.0–2.5 m into the mud and placed
next to each other (13,000 poles/km long) and created a small gap
from 2–5 cm between adjacent poles. A layer of bamboo matting
(1.0–1.2 m high, 1.5 m long) and
fine
fishing net was placed in front
of the pole row. A frame (3 m long and 1.5 m high) made from
Melaleuca (pole 3) was attached to the front and back of the row of
poles. This kept the bamboo mat and
fishing net in place despite
wave action. Building cost of the silt trap fence is US$10,000/km,
plus US$2000/km for damaged repairing and maintenance after
2 years.
Fig.