Ved :

Cloud seeding
Dikes - Holland
Thames barrier
Sea wall

A seawall is a coastal defense system, constructed where the sea (or other coastal water bodies), impact directly upon the coastal land. The purpose of a seawall is to protect areas of human habitation, conservation and leisure activities from the action of tides and waves. As a seawall is a man made structure made of cement, it will interfere with the land and water sediment exchanging. Seawalls are classified as : “A hard engineering shore based structure used to provide protection and to lessen coastal erosion.”. However, a range of environmental problems and issues may arise from the construction of a seawall, including disrupting natural sediment movement / exchange. Seawalls can be constructed from a variety of materials, most common materials being :

Reinforced Concrete,
Boulders,
Steel,
Gabions,
Wood,
Aluminium,
Vinyl,
Fibreglass,
Jute,
Coir

Seawalls come in multiple types, the few most common being :

Vertical : Vertical seawalls are built in places that our very exposed to wave energy. The simply act as dikes, to help make sure that water doesn 't go out of control.
Advantages :
This is one of the easiest and most basic version of seawalls.
It is cheap to make.
Extra material helps back water of.
Disadvantages :
Prune to a lot of water damage.
Erodes quickly.
Gain holes.

Curved : Curved seawalls let the waves break as they go up the seawall, reducing direct impact. They are used in places that