How Rivers Are Formed

1. How Rivers Are
Formed
Junhel C. Dalanon, DMD, MAT
SNSCLC – Minglanilla
Minglanilla, Cebu, Philippines 6046

2. Stages of River Development
1.Youth Stage
2.Maturity Stage
3.Old Age Stage

3. Youth Stage
Water falls on land surfaces
Runoff from many streams collect in low places
and form gullies
Beginning stream will flow after heavy rains
A valley is formed containing a permanent
stream
Gullies become tributaries
Headward erosion lengthens extensively the
valley

4. Maturity Stage
Channels form from tributaries due to continuous
erosion
Regions of higher ground that separate drainage
basins are known as divides
Stream Piracy happens when one stream may cut
through a divide and diverts the water
Velocity of river to erode land = velocity of stream
Velocity of stream = amount of water + slope
Maturity is attained when river is graded
Graded means the ability of river to transport is equal
to deposition rate

5. Old Age Stage
•As river grows old, slope becomes less steep
•Old age river:
1.Wider valley
2.Relatively flat floor
•Meanders – wide curves