The Ganges Basin Development Challenge (GBDC)

Increasing the resilience of agricultural and aquaculture systems in the coastal

areas of the Ganges Delta

Andes • Ganges • Limpopo • Mekong • Nile • Volta

Water for a food-secure world

The short, short version• Coastal Bangladesh, seasonal salinity, “polders”

• Low productivity farm systems

• Enormous potential to intensify systems if better water control

• But infrastructure for water control needs improvement

• Multiple institutions working on water infrastructure –coordination problems

• CPWF projects working with National Planning Commission and other local institutions on practical steps to upgrade infrastructure – could involve up to USD1b of investment

Andes • Ganges • Limpopo • Mekong • Nile • Volta

Water for a food-secure world

LOCATION OF GANGES RIVER BASIN

Polde

r 31

Polder 30

Ri

ve

rInlet to

sluice

gate

Sluice

gate on

river sideSluice

gate

inside the

polder

Focal study areas in Bangladesh

West Bengal, IndiaSouth West Bangladesh

Patuakhali STU

Polder 43/2/F

Polder 30

Polder 3

North 24 Parganas

South 24 Parganas

Andy Nelson

“LOW SALINITY”

•Water “stagnation” 30-50 cm

several weeks in aman

•River water fresh 10-11 months

•Mild soil salinity in dry season

“MEDIUM SALINITY”

•Water “stagnation” 30-50 cm

several weeks in aman

•River water saline mid-Feb-Jun

•Medium soil salinity in dry

season

“HIGH SALINITY”

•Water “stagnation” 30-50 cm

several weeks in aman

•River water saline Dec-Jul

•High soil salinity in dry

season

Increasing area affected by soil salinity

Soil salinity

None

Very slight

Slight

Strong

Very strong

3/12

Study sites for improved technologies

Polder 3

Rice/Aquaculture &

Shrimp/Shrimp

Polder 30

Intensification from one to

two crops

Polder 43/2f

Intensification from

one/two to three crops

2/12

10 Apr

30 June

10 July

15 Nov 05Apr

Rabi (130-140 d)

1 Dec

T. Aman (130-140 d)Aus (100-105 d)

A M J J A S O N D J F M A

Low salinity areas: Aus-Aman-Rabi Cropping System

15 July

15 Nov 30 AprRabi (120-140 d)

Dec/Jan

Aman (140 d)

M J J A S O N D J F M A M

Terminal Drainage

Moderate salinity areas: Aman-Rabi Cropping System

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Wet seasonDry season

Gher

preparation

Seedling

Bagda Rice+Fish

High salinity areas: Improved aquaculture-rice

Drain out saline water,

expose gher soil to

rainfall to leach down

soil salinity

Poorly-drained gher in polder 3 Well-drained gher

Average of Peak water level during kharif-2

• In the low saline zone freshwater is available for the whole year at presentand future and three crops can be established instead of one crop atpresent;

• Gravity irrigation is feasible during Aman Crop;

• Costal polder needs improved water management with additional drainageand flushing sluices and ensuring proper operation of gates;

• Internal road network needs adequate number of cross-drainage structurefor drainage improvement;

• Excavation of internal drainage khal for drainage improvement and waterstorage for agriculture;

• In the high saline zone, unauthorized pipes/structure are used for salinewater supply can be replaced by few number of flushing sluices for betterwater and conflict management and safety of the embankment ;

• The effects of external drivers on water resources is significant and needs tobe considered in future plannning.

Details: What “water control” means in this case

Re-defining the roles of polders

• Each polder needs to be considered as an integrated water management unit

• The original role of the polders was to enable one crop of tall, long duration traditional aman rice

• HYVs & improved cropping system technologies now available, but require better water control

Effective water management at polder level require separation of lands on the basis of land topography to form a small water management unit by about 50 cm high farm levee

How to reduce drainage problems and conflicts?

Divide polders into smaller hydrological units (SHU).

Use LGED rural roads as hydrological boundaries

For even smaller boundaries, use UP social safety funds for ail construction

Why are water infrastructures not maintained?

• WMOs were created for solving ‘deferred maintenance’

• Why communities don’t maintain?– Public goods dilemma

– Even so called ‘minor’ repair and maintenance may be beyond the capacity of communities

– Incentive problems: if communities don’t fix it in time, government or donor will in a few years time

Solutions beyond community levels

• Use existing social safety net funds of UP, like 40 days work, KABHIKA for polder maintenance

• Twin benefits of employment creation (LCS) and infrastructure maintenance

• Coordination between UP, BWDB, LGED and Central Government

Solutions by donors and central government

• Create of Donor-Government Trust Fund for Maintenance of Water related infrastructure in Bangladesh

• All polder/sub-projects get allocations for repair and maintenance every year from interest amount of Trust Fund

GoB

Development partner

Donor Government Trust Fund

Trust fund money is allocated to every polder each year for Repair and Maintenance

Polder 31

Polder 30

River

Inlet to sluice gate

Sluice gate on river side

Sluice gate inside the

polder

5 research projects - expected outcomes Use of suitability domain maps as a decision support toolsDevelop, evaluate, and adapt new and improved cropping and aquaculture systems

Better polder governance through reduced conflict between fishermen and farmers

Understanding of the key external drivers of change in water resources

Establish a policy framework for scaling up/out of technologies to enable changes in HH of Ganges coastal zone (team effort)

Thank you