Ganges Basin Development Challenge

Objective: Improve resource productivity and increase the resilience of agriculture and aquaculture systems of brackish coastal areas of the Ganges

G4: Assessment of the Impact of Anticipated External Drivers of Change

on Water Resources of Coastal Zone

Ganges Basin:

Ganges Basin Area = 1,087,300 sq. km

Study Area:

Ganges Dependent Area in Bangladesh

Coastal Divisions: Barisal: Patuakhali, Barguna, Jhalakati & Pirojpur districtsKhulna: Khulna & Satkhira districts

Project Target Area:Coastal Zone of the Ganges basin in Bangladesh except the Sundarbans

Problems and Challenges in the Coastal Region of Bangladesh

Water logging

Increase in precipitation in monsoon

Decrease in precipitation in dry season

Salinity intrusion

Cyclone

Sea level rise

Increased frequency of tropical cyclone

Added siltation on the drainage route

Salinity intrusion

Flood

Salinity Intrusion

Important Developments: •Coastal Zone Policy•Coastal Development Strategy•Priority investment program•Community capacity to enhance livelihoods•Enabling institutional environment•Integrated knowledge base

Water Related Issues: •Water, land and ecosystem management •Community participation in water management•Equitable allocation of multi-purpose cyclone shelters•Rationalization of coastal polders• Restoration of inflow to the Ganges distributary by basin wide management•Salinity intrusion•Drainage congestions & Sedimentation•Climate change and climate variability

DRIVERS PRESSURE/CONSEQUENCESDemographic/SocietalPopulation growth, Land use change

Water demand & useLoss of biodiversity and wetlands

Economic/TradeEconomic develpopment (change in per capiata income)Market value of agricultural products

Shift in land useWater Demand, water PollutionRoads, railway & ports

Political/Institutional/LegalWater policy (national and regional)

Improved Irrigation and drainage system, Water availability in the dry season

Environmental/Climate ChangeSea level rise due to Climate ChangeChanges in precipitation and temperature due to Climate Change , Subsidence

Fresh water shortage, Salinity intrusion, FloodSedimentationMore Cyclone & Storm surge

Technological/Important Innovations aquaculture and agriculture intensification, Water infrastructure development

Enhanced knowledge and use of HYVEnabling environment

Drivers of Change: Participatory Approach

Place: Fultola, BatiaghataParticipant: Farmers (3 women, 20 men)

Priority Issue1 Increase of water level & salinity intrusion, Polder needs to be raised, some of the

existing gates need to be repaired and new gates are required to be constructed

2 Need improvement in drainage and excavation of new drains/canals, new sluice gates/inlet-outlet

3 WGMs want to be able to operate the gates themselves and to lease the ‘Khas lands’ near the embankment and gates to generate funds for their activities.

4 Stop leasing of the canals

5 Solve the problem of river siltation and improve navigation

6 Water management through public representation and partnership

7 Capacity building and training

Community Consultation at Polder 30

Place: Kismat-fultola, BatiaghataParticipant: Fishermen (6 women, 9 men)

Priority Issue

1 Stop leasing the canals

2 Stop placing ‘net’, ‘pata’, ‘charu’ or obstruction in the canals/river

3 Increase depth and flow in canals

4 Stop catching mother fish carrying eggs

5 Reduce using pesticides for agriculture

6 Stop unnecessary catching of juvenile fish of other species

7 Stop complete drying of canals while irrigation so that some fish/egg may survive/remain in the canals for future growth

Popu

latio

n G

rowt

h

Chan

ges

in W

ater

Mgt

Sea

leve

l rise

Land

use

cha

nge

Wat

er S

harin

g

Tran

sbou

ndar

y flo

w

Aqua

cultu

re in

tens

ifica

tion

Econ

omic

Deve

lpop

men

t

Urba

niza

tion

Wat

er in

frast

ruct

ure

deve

lop.

..

Chan

ges

in p

recip

itatio

n

Wat

er P

olicy

Indu

stria

lizat

ion

Wat

er G

over

nanc

e &

Inst

itut..

.

Wat

er U

se c

hang

e

Mar

ket V

alue

of A

gro

Prod

ucts

Chan

ges

in te

mpe

ratu

re

Diet

ary

patte

rns

Wat

er P

ricin

g &

Insu

ranc

e

6.5%6.1%5.9%

5.7%5.7%5.5%5.4%5.4%5.4%5.4%

5.2%4.8%

4.6%4.6%4.4%4.3%4.2%

3.2%2.8%

Perc

enta

gePreliminary Results of Questionnaire Survey

Hydrologic Trend Analysis in the Study Area:

1930 1940 1950 1960 1970 1980 1990 2000 20100

10000

20000

30000

40000

50000

60000

70000

80000

90000Hardinge Bridge on the Ganges

Max Q Linear (Max Q) Min Q Linear (Min Q)Average Q Linear (Average Q)

Disc

harg

e (m

3/s)

• Increasing trend of annual maximum flow

• Decreasing trend of annual minimum flow

Trend Analysis of Ganges River Discharge

Hydrologic Variables:Trend Analysis in the Study Area:

Trend Analysis of Water Level

1980 1985 1990 1995 2000 2005 2010-2

-1

0

1

2

3

4 Hiron Pointon the Pussur River

Max of WL Linear (Max of WL) Min of WLLinear (Min of WL) Average of WL Linear (Average of WL)

Wat

er L

evel

(mPW

D)

• Rising trend of water level near the sea

1999 2001 2003 2005 2007 20090

1

2

3

4Hiron Pointon the Pussur River

Max of WL Linear (Max of WL)

Wat

er L

evel

(mPW

D)

The increase of maximum water level is 6 cm/yr at Hiron Point in the last 10 years.

Jan/

2005

Jan/

2005

Mar

/200

5Ap

r/20

05M

ay/2

005

May

/200

5Ju

n/20

05Ju

l/20

05Au

g/20

05Se

p/20

05O

ct/2

005

Nov

/200

5De

c/20

05Ja

n/20

06Fe

b/20

06M

ar/2

006

Apr/

2006

May

/200

6Ju

n/20

06Ju

l/20

06Au

g/20

06Se

p/20

06O

ct/2

006

Nov

/200

6De

c/20

06Ja

n/20

07Fe

b/20

07M

ar/2

007

Apr/

2007

May

/200

7Ju

n/20

07Ju

l/20

07Au

g/20

07Se

p/20

07O

ct/2

007

Nov

/200

7De

c/20

07Ja

n/20

08Fe

b/20

08M

ar/2

008

Apr/

2008

May

/200

8Ju

n/20

08Ju

l/20

08Au

g/20

08Se

p/20

08O

ct/2

008

Nov

/200

8De

c/20

08Ja

n/20

09Fe

b/20

09M

ar/2

009

Apr/

2009

May

/200

9Ju

n/20

09Ju

l/20

09Au

g/20

09Se

p/20

09O

ct/2

009

0

2

4

6

8

10

12

Noapara Ghat Fultola Ghat Charerhat Ghat Rupsha Ghat Mollarhat

Salin

ity (P

PT)

Salinity Trend in the Region

Monthly Salinity Monitoring (Data Source: Department of Environment, DOE)

Population growth• One of the densely

populated country

• Projected population

o 2025: 180million

o 2050: 220 million

• Urban: 25 million (2001), 80 million (2025) & 140 million (2050)

• Reduction of agricultural land 1% annually

70

80

90

100

110

120

130

140

Po

pu

lati

on

(m

illio

n)

7.0

7.5

8.0

8.5

9.0

Cro

pp

ed

are

a (

millio

n h

a)

Cropped areaPopulation growth

020406080

100120140

1998

2005

2015

2025

2035

2045

Rural Urban

Coastal Polders in Bangladesh

In the early sixties and seventies, 125 polders (of which 49 are sea-facing) were constructed to protect low lying coastal areas from tidal flood & salinity intrusion.

West Bengal Bangladesh

Polder 43/2/F trials

Polder 30 trials andstudy watershed

Polder 3 trials

S elected Polder in coastal zone of Bangladesh and West Bengal

Trial sitesG1 IRRI – IWM – LGED - SRDI

0 SLR60 cm SLR120 cm SLR

Impact of SLR on Intrusion of 5ppt Salinity line Dry Season

Hiron Point

95 km

55 km

Sundarbans

Khulna

Barisal

Bhal

esw

ar R

iver

Tent

ulia

Riv

er

BholaBarguna

Patuakhali

Sea Level Rise (SLR)

Affected area (ha)due to SLR

Affected Population due to SLR

60cm 512,590 4,613,306120cm 1,061,016 9,549,144