AS WATER MOVES DOWNSTREAM AND AROUND A BEND, IT MOVES IN A SPIRAL FASHION.
IT MOVES TOWARDS THE OUTER BANK OF THE CURVES AT A GREAT VELOCITY, ERODING THE BANK.
MUCH OF THE ERODED MATERIALS IS THEN CARRIED TOWARDS THE OPPOSITE BANK AND IS DEPOSITED THERE.
DEPOSITION TAKES PLACE BECAUSE OF THE FRICTION BETWEEN WATER AND THE RIVER BANKS AND BED IS GREAT, REDUCING THE VELOCITY.
THE WATER THEN MOVES DOWNSTREAM TOWARDS THE NEXT BANK IN A SPIRAL MANNER AND THE PROCESS IS REPEATED.
OVER TIME AT THE OUTER BANK, A RIVER CLIFF IS FORMED AND THE BANK BECOMES CONCAVE IN STEEP SLOPE SHAPE.
AT THE OPPOSITE BANK, A GENTLE SLIP OFF SLOPE IS FORMED AND AT THE BANK BECOME CONVEX.
THIS CONVEX AND CONCAVES IN A MEANDER GIVES THE CHANNEL AN ASYMMETRICAL SHAPE.
WHEN A RIVER BENDS AND TURNS, IT IS SAID TO BE MEANDERING
THE CURVES OR BENDS ALONG THE RIVERS ARE KNOWN AS MEANDERS.
Question 1-What kind of delta is this in picture 1?
Question 2- what kind of delta is this in picture 2
DELTA IS A FLAT PIECE OF LAND THAT IS MADE UP OF LAYERS OF SEDIMENTS DEPOSITED AT THE RIVER MOUTH OVERTIME.
THERE ARE TWO TYPES OF DELTA
1.FAN OR TRIANGLE SHAPED– WHEN THE RIVER DEPOSITS ITS LOAD UNIFORMLY OVER THE WHOLE YEAR.
2.BIRD’S FOOT– WHEN THE RIVER DEPOSITS ITS LOAD RAPIDLY AT THE RIVER MOUTH AND EXTEND OUTWARDS INTO THE SEA LIKE A CLAWS OF BIRDS.
AS THE RIVER APPROACHES TO THE CALMER SEA WATER, ITS VELOCITY DECREASES. IT STARTS TO DEPOSIT ITS LOAD AT THE MOUTH.
AS THE SEDIMENTS CONTINUE TO ACCUMULATE, THEY OBSTRUCT THE PATH OF THE RIVER WHICH THEN BRANCHES INTO SMALLER RIVERS (DISTRIBUTARIES) TO FIND A WAY AROUND THE OBSTRUCTION.
THE SEDIMENTS ARE CARRY WATER AWAY FROM THE MAIN RIVER IN SEVERAL DIRECTIONS BEFORE FINALLY REACHING THE SEA
OVER TIME LAYERS OF DIFFERENT MATERIALS SUCH AS SAND, SILT AND CLAY ARE BUILT UP ON THE SEA FLOOR AND A DELTA FORMED
During the deposition, the coarser alluvium is deposited nearer the bank of the river while the finer alluvium is carried and deposited further from the bank.
The continuous accumulation of the coarser alluvium along the banks of the river forms natural embankments called leeves
A floodplain is a wide and flat plain.
It is built up by alluvium ( fine rock i.e. silt and clay) laid down on the river banks during repeated flooding.
The formation of Flood Plain when the river has overflowed its banks.
The flood subsides , there is a decrease in the volume of water and the river starts to deposit its load repeated and forming a flood plain features.