3. River Erosion
Wearing away of rocks and other deposits from earth’s surface
by the action of water, ice, glacier, winds, waves etc.
Affecting the socio-economic situation
A hindrance in sustainable development
Leaves a long lasting devastating affect in
the lives of the sufferes
Erosion also involves the breaking down of the rock particles being
carried downstream by the river
4. River Erosion: A Threat to Bangladesh
An endemic and recurrent natural hazard in Bangladesh
Bangladesh considered as a river reign country
5% Floodplain of Bangladesh is directly affected by river erosion
Nearly 94 upazilas near major rivers are sufferers of river erosion
34 upazilas are severely affected including Kajipur, Faridpur, Shariyatpur,
Madaripur, Comilla, Chadpur, Shirajganj
About 700 rivers and 60 of them are major rivers
In a year about 2400 km of river bank line experiences major erosion
About 40% migration to Dhaka is due to river erosion
5. Processes of river erosion:
Hydraulic Action:
Decomposition of rock particles from river bed due to water
pressure
Occurs near water falls and fierce forced streams of rivers
Abrasion:
Wearing away of river banks by river sediments.
Occurs during the depression stage of rivers
6. Attrition:
Eroded particles collide and break into smaller
particles
Corrosion:
Carbon di oxide dissolves in the river to form a
weak acid.
The edges of rock particles becomes more
rounded and smaller
Attrition makes the sediment particles smaller
It forms limestones and chalks are found as
sediments
7. The major rivers responsible for river erosion:
The Padma
The Upper
Meghna
The Lower
Meghna
The Jamuna
The
Brahmaputra
10. Jamuna Ganges Padma Upper Meghna Lower Meghna
Bank
Erosion
Rate
(m/year)
Left 100 20 38 7 66
Right 84 56 121 9 182
Maximum Bank
Erosion Rate
(m/year)
784 665 620 NA 824
Rate of river erosion
Source: ISPN,1995, Rates are derived from 1984-1992
11. Width decrease in major rivers:
The Jamuna The
Brahmaputra
The Padma The Upper
Meghna
The Lower
Meghna
Average
width
(m)
1984 9,720 4,367 5,689 3,406 6,661
1993 11,220 4,693 7,116 3,391 8,897
Rate of change
of
width(m/year)
184 36 159 2 248
Source: ISPN,1995
12. Micro-level Analysis On Kazipur upazila:
Situated near the Brahmaputra river
Severely affected by river erosion
Source: Google Map
13. Scenario of a river erosion affected area:
Kazipur-a upazila of 11 unions
During 2009 the nearest branch of the river
grew and shifted 200 meter west
As a result Kazipur lost estimated 2,000 acres
OR 40% of agricultural land
Brahmaputra Right Bank flood control
embankment passes through the upazila of
Kazipur. It could stop flooding not erosion.
An luminous example of how prevention is
ineffective in case of river erosion
15. Socio-economic effects
Estimated 1,000,000 people are affected annually
Estimated 500,000,000 USD monetary loss annually
A big set back for agriculture
Erodes farmland, infrastructure and communication system
Lifestyles of native people degrades drastically
Affected people lose assets and fall in future debt
Migration of inhabitants
River erosion is considered as a major cause of growing poverty
16. A Family Which Has
Been The Cruelest
Victim Of River
Erosion
Tale of a Taher Mollah
Source: USAID
17. Taher Mollah- scenario of 2012
Used to own 60 bighas (20 acres) of land
Born in 1950 in a well off family in khidirpur.
Lived as a day labourer in the city of Rajshahi
Still hoped of going back to the
char when it will rise.
Due to river erosion he has lost all. Even his
living place.
Irony of his life was he never got
to see his living place again.
Source: USAID
18. PREDICTION METHOD OF RIVER EROSION
USING RIVER MORPHOLOGY
River Morphology:
Describes how river channels change directions and shapes with time
Recent satellite images
Re-derived methods based on channel network
analysis
Tools used:
20. TWO MAJOR PROJECTS:
JAMUNA-MEGHNA
RIVER EROSION
MITIGATION PROJECT
DISSAPPEARING LANDS
PROJECT
Enhance Economic Growth
Reduce Poverty
Ensure Livelihood Security
Already Changed About 2,000,000 Peoples’ lives
Objectives Of The Projects
