Beach Nourishment

Beach nourishment describes a process by which sediment (usually sand) lost through longshore drift or erosion is replaced from sources outside of the eroding beach. Sand fill must be compatible with native beach sand. In some cases, beaches have been nourished using a finer sand than the original. 
Seafloor habitat in both source and target areas are disrupted, e.g., when sand is deposited on coral reefs or when deposited sand hardens. Imported sand may differ in character (chemical makeup, grain size, non-native species) from that of the target environment.


information: http://en.wikipedia.org/wiki/Beach_nourishment

Coarse sand

Fine sand

Pictures taken at east coast park.

Breakwaters

Breakwaters creates a zone of shallow water between itself and the coast, so that waves will break against it before reaching the coast. Thus reducing costal erosion.

Breakwaters are usually made of granite and are parallel to the coast. The cost of each breakwater is estimated to be around $1million. The disadvantage is they are unable to provide complete protection and leaves certain areas unprotected. The unprotected areas would face coastal erosion.

Breakwater

With breakwaters, the waves hit the breakwater before hitting the coast. Thus, reducing the speed and energy of the waves, causing less coastal erosion.

Without breakwaters, the waves hit the coast directly and cause more coastal erosion.