1.2. Description of study site
The study site where the Marine Department wants to construct
detached breakwaters is a 7-km coastal stretch in Nakhon Si
Thammarat province, Thailand, located in Ban Nastone village, Hua
Sai district (Fig. 1). Waves mainly come from the east and normally
the offshore wave height is less than 2 m but the height can be
greater than 3 m during storms. Over a 50-year period, significant
wave height is estimated to be 4.12 m with a wave period of 9.8 s.
Coastal sediment is sand with a mean grain diameter of 0.3 mm and
the net alongshore sediment transport rate is roughly 91,000 m3
/
year, moving in a southerly to northerly direction.The target area, which is subject to an EIA, is bounded by two
coastal structures. There is a 450-m long jetty at the southernmost