HAVE EVER

THOUGHT YOU

EROSION

ABOUT RIVER

AND HOW IT’S AFFECTING

BANGLADESH

River ErosionWearing 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

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

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

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

The major rivers responsible for river erosion:

The Padma

The Upper Meghna

The Lower MeghnaThe Jamuna

The Brahmaputr

a

THE MAJOR CAUSE FOR

RIVER EROSION SHIFTING OF RIVER CHANNELS

Source: Google Earth

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

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

Micro-level Analysis On Kazipur upazila: Situated near the Brahmaputra river

Severely affected by river erosion

Source: Google Map

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

Before river erosion After river erosion

Source: Google Earth

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

A Family Which Has Been The Cruelest Victim Of River ErosionTale of a Taher Mollah

Source: USAID

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

PREDICTION METHOD OF RIVER EROSION USING RIVER MORPHOLOGYRiver Morphology:

Describes how river channels change directions and shapes with time

Recent satellite images

Re-derived methods based on channel network analysis

Tools used:

GOVERNMENT MEASURES

PREVENTION

MITIGATIONNOT

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

BEING COMPASSIONATE

IS THE KEY