WATER IS THE MOST IMPORTANT NATURAL
RESOURCES FOR PLANET EARTH
THE PROSPERITY OF A NATION DEPENDS
PRIMARILY UPON THE EXPLOITATION OF THIS
RESOURCES. THUS IT CAN BE STATED THAT THE
PRIMARY WEALTH OF A NATION IS WATER,
WHICH FLOWS IN THE RIVER OR STREAMS.
The force of water wears away the
river bank from underneath. The
pressure of water breaks the rock
particles. Water force hits river banks
and pushes water into cracks. Thus the
pressure expands the cracks and
breaks the rocks into fragments.
What i s At t r i t ion ?
Rocks being carried by the rivers
smash together and break into
smaller particles. Overtime, they
become smaller and eventually
reduced t fine particles called silt.
CO2 dissolves in the river to form a
weak acid. This dissolves rock by
chemical processes. This process
is common where carbonate rocks
such as limestone & chalk are
evident in the channel.
A typical drawing of four types of River Erosion Process
To prevent the river from changing its coarse & to avoid
outflanking of structures like bridges, weirs etc.
To prevent flooding of the surrounding areas by providing a
safe passage for the flood waters without overtopping the
To protect the river banks by deflecting the river away
from the attacked banks.
To ensure effective disposal of sediment load.
Marginal embankment or Levees
Groynes or Spurs
Levees are generally earthen
embankments, running parallel to
the river. These embankment-wall
retain the river water to carry the
bank soil with the water.
The guide banks are generally provided
across a river as to ensure not only a safe
and expeditious disposal of flood water
but also to ensure a permanent reasonable
width of the waterway for the river flow.
Symmetrical and parallel guide banks
are usually adopted.
Groynes are the embankment type
structures, constructed transverse to the
river flow to protect the bank by
deflecting the current away from the
bank. As the water is unable to take a
sharp embayment, the bank gets
River controlling methods mainly depends upon the
type of the river, its regime and the flow
characteristics of the river. So the methods to control
the river erosion varies from place to place.
Hence, no particular method of river controlling can
be stated to be the best. A comprehensive planning
and model testing is necessary before any measure are
undertaken to control the river.