18
23-engineers build hard structures along the shore to absorb the energy
of the waves : a-true.
b-false.
24-some of these hard structures are : a-docks and harbors.
b-seawalls , groins, seawalls…..
c-coastal refineries.
25-groins : a-are smaller and cheaper than jetties.
b-are larger and more expensive than jetties.
26-breakwaters : a- are designed to trap sand and preventing the sea
from washing it away .
b-are built to absorb the energy of the waves and cause them them to
break offshore.
27-seawalls : a- are designed to protect buildings and roads and the
beaches from eroding.
b-refer to the sand that accumulate in the beach.
28-seawalls : a- have some disadvantages and may not be effective way
for protecting the coasts.
b-are an effective way for protecting the coasts from erosion.
29-replenishing the beach with sand is called : a-beach nourishment.
b-beach retreat.
Exercise : answer the following questions :
1-what are the different factors that change the shape of the coasts ?
2-what are the different zones that make up the nearshore zone ?
3-where is the offshore zone situated ?
4-where is the backshore zone situated ?
5-what is the beach profile ?