By Urs Schulthess, Timothy J. Krupnik, Zia Uddin Ahmed, Andy J. McDonald Revitalizing the Ganges Coastal Zone Conference 21-23 October 2014, Dhaka, Bangladesh http://waterandfood.org/ganges-conference/

1. Urs Schulthess ⏐Timothy J. Krupnik ⏐Zia Uddin Ahmed ⏐Andy J. McDonald
Decentralized Surface Water Irrigation as a pathway for sustainable
intensification in Southern Bangladesh:
On how much land can the drop be brought to the crop?

2. A three part presentation:
1. Surface water irrigation as a pathway
to sustainable intensification (SI) in
Southern Bangladesh
2. Targeting decentralized surface water
irrigation to boost double cropping
3. Future research and conclusions

3. Part 1: Surface water irrigation as a pathway to
sustainable intensification (SI) in Southern Bangladesh

4. Meandryseasongroundwatertabledepth(m)
The emerging irrigation bottleneck in intensive boro production zones
Source: Qureshi, Ahmed, and Krupnik (2014)

5. The Master Plan For Agricultural Development In The South
The Southern Delta of Bangladesh
• Low crop intensification and fallows
• 3.44 million farm households, majority poor
(MoA and FAO, 2012)
• Rice-based farming system
• Target for most international aid
The Southern Delta Master Plan:
A $7.2 billion donor investment request
• The south: Dense network of rivers and
canals, poorly used for irrigation
• Emphasis on expanding surface water
irrigation to alleviate irrigation
bottlenecks in the North
• Key aim: sustainable intensification to
boost productivity and alleviate poverty

6. Sustainable intensification (SI) in Southern
Bangladesh
In practice, SI has two major approaches:
• ‘Crop’ intensification:
Boosting yield, while sparing resources and harnessing
ecological services (e.g., yield focused)
• ‘Systems’ intensification:
Moving from one to two crops, while sparing resources
and harnessing ecological services (e.g., double
cropping focused)
• Bangladesh: loosing agricultural land (-10% in the last
decade) (Hassan et al. 2013)
• SI: ‘. . . producing more output from the same area of land
while reducing the negative environmental impacts and …
increasing contributions to natural capital and the flow of
environmental services’ (Pretty et al. 2011)

7. Irrigation a must to scale up double cropping in Southern Bangladesh

8. How can dry season irrigation be encouraged?
• Large-scale, centralized irrigation schemes?
Extremely costly and challenging to maintain:
• Ganges-Kabadak (1955) – most land in 72,000 ha already double cropped. Siltation, bank
instability, etc. (Brammer, 2002)
• Barisal Irrigation Project (1980). Slated for 42,000 ha achieved < 20% (cf. Gumma et al.,
2014).
• Unfavorable conditions for farmers to access and use state provided pumps (Brammer, 2002)
• Bangladesh’s historical irrigation boom: thousands of
decentralized irrigation service providers serving 10–20 ha
Supplies 90% of Bangladesh’s irrigation (Chowdhury, 2010)
Could this work for Southern Bangladesh?
• Technological options exist to address energy and
cost problems (Axial flow pumps, other pumps)
• Service provider networks and water users groups
need to be established
• Problems remain with appropriate siting of small
command schemes to encourage double cropping
Krupnik et al. 2013

9. Part 2:
Targeting
decentralized surface
water irrigation to
boost double cropping

10. Forgoing the fallow and establishing rabi croppin
• Location and estimates of fallow land vary by year, method, and
definition:
• 800,000 ha (Rawson et al., 2011)
• 634,000 ha (BADC 2010)
• 136,000 ha (MoA and FAO, 2012)
• 240,000 ha (BBS, 2011)
• No estimates are related to targeting fallows for surface water irrigation
and intensification
• Analytical challenges: Fallow identification, soil and water salinity, water
availability, timely land availability

11. Targeting ‘best-bet’ areas for intensifying cropping
using surface water irrigation in S. Bangladesh
A complex process using GIS and
remote sensing (RS)
Using publically available data
• Hydrozone à GIS
• Water ways à RS
• Duration of surface water à RS
• Water salinity à monitoring/GIS
• Soil salinity à survey/GIS (SRDI)
• Land type à Elevation
• Crop land à RS
• Land use intensity à RS

12. Study area: South Central and South West Bangladesh
Area:
3.374
million
ha

13. Dynamic river system
feet
km
4000
1
feet
km
4000
1
feet
km
4000
1
Apr
12,
2014
Nov
23,
2009
Feb
17,
2004

14. Surface Water

15. Presence of surface water in January
Feyisa,
G.L.,
Meilby,
H.,
Fensholt,
R.,
Simon,
R.,
Proud,
S.R.,
2014.
Automated
Water
ExtracKon
Index:
A
new
Technique
for
surface
water
mapping
using
Landsat
imagery.
Remote
Sensing
of
Environment
140,
23-­‐35.

16. Presence of surface water in February

17. Presence of surface water in March

18. Surface water salinity in January
Source
of
surface
water
salinity
data:
BWDB.
Data
from
2002–2012
were
used.

19. Surface water salinity in February

20. Surface water salinity in March

21. Surface water salinity in April

22. Soil salinity
Source:
SRDI,
2000.
Soil
Salinity
Bangladesh.
Soil
Resources
Development
InsKtute.,
Dhaka,
Bangladesh.

23. Suitability Matrix based on surface water and soil
salinity
0"#2 "2"#"4" >"4
"0"#2" Highly"suitability Medium"suitability Non"suitable
"2"#"4" Medium"suitability Low"suitability Non"suitable
>"4 Non"suitable Non"suitable Non"suitable
Water&Salinity&[dS/m]
Soil&
Salinity&
[dS/m]

24. Land suitability based on soil and surface water
salinity

25. Landscape elevation (Kharif inundation class)
Above
flood
level
Up
to
90
cm
90
–
180
cm
180
–
300
cm
>
300
cm
Normal
flooding
depth
Aer:
Brammer,
H.
2012.
The
physical
geography
of
Bangladesh.

26. Reflectance of light from leaves as function
of wavelength
NDVI =
NIR - Red
NIR + Red
Normalized
difference
vegetaKon
index

27. 27
Ground Cover (GC) and Leaf Area Index (LAI)
Ground Cover is the
percentage of ground covered
by green vegetation when
seen from above. It is a good
indicator of:
Productivity
Stresses
Diseases
GC
=
1
–
exp(-­‐k
*
LAI)

28. Prediction of LAI with the Enhanced Vegetation
Index (EVI)
Guindin-­‐Garcia,
N.,
Gitelson,
A.A.,
Arkebauer,
T.J.,
Shanahan,
J.,
Weiss,
A.,
2012.
An
evaluaKon
of
MODIS
8-­‐and
16-­‐day
composite
products
for
monitoring
maize
green
leaf
area
index.
Agric.
For.
Meteorol.
161,
15-­‐25.

29. Using EVI to assess rabi land use intensity
2013-14

30. Using EVI to assess rabi land use intensity
2013-14

31. Using EVI to assess rabi land use intensity
2013-14

32. Using EVI to assess rabi land use intensity
2013-14

33. Using EVI to assess rabi land use intensity

34. Using EVI to assess rabi land use intensity

35. Using EVI to assess rabi land use intensity

36. Resulting land use intensity, rabi 2013–14

37. Resulting land use intensity in Southern Bangladesh (ha)
Cropping intensity 2011–12 2012–13 2013–14 Average
Fallow land 271,078 218,806 230,824 240,236
Low-intensity 779,095 915,548 906,382 867,008
High-intensity 876,338 790,732 789,735 818,935
Total 1,926,179

38. Resulting land use intensity in Southern Bangladesh (ha)
Cropping intensity 2011–12 2012–13 2013–14 Average
Fallow land 271,078 218,806 230,824 240,236
Low-intensity 779,095 915,548 906,382 867,008
High-intensity 876,338 790,732 789,735 818,935
Total 1,926,179
Compared to previous estimates for fallow land:
• 800,000 ha (Rawson et al., 2011)
• 634,000 ha (BADC 2010)
• 136,000 ha (MoA and FAO, 2012)
• 240,000 ha (BBS, 2011)
All methods based on survey sampling and up-scaled estimation, with exception
of Rawson et al., who included low-intensity crop land.

39. Targeting surface water irrigation to fallow and low
land use intensity land

40. Detailed view: Land use intensity

41. Detailed view: Targeting surface water irrigation on
fallow and low land use intensity land – 400 m buffer

42. Addressable land (ha) within a 400 m buffer of
detectable surface water bodies (late March)
Land use Highly Medium Low Not
Intensity Suitable Suitability Suitability Suitable
Fallow 14,524 6,866 2,144 23,631
Low Intensity 86,451 17,262 6,640 22,302
High Intensity 66,639 6,524 999 7,419
Total 167,615 30,652 9,783 53,352
The key output of this work is a detailed spatial database
indicating the precise location of high- and medium- suitability
fallow and low intensity lands upon which surface water irrigation
could provide the key to unlocking the South’s agricultural
productivity.
This data base will soon be online and made available for
development organizations, researchers, and policy makers.

43. Caveats
• Our estimate is conservative:
FINNMAPS indicate we
detected just ~25% of rivers
and canals in the irrigable
zone
• Methods are needed to
rapidly assess water volume
• Cooperation is key: Good
water governance and canal
rehabilitation will be crucial
for sustainable intensification.
• Research is needed to fine-
tune irrigation scheduling
recommendations to increase
WP

44. Part 3:
Future research: IrMASaT project
(Irrigation Management Advisory with Remote Sensing)

45. Main high potential target zone for surface water irrigation
Objectives:
• Regional and sub-regional watershed and
scales: “safe operating space in canal systems”
• Surface water irrigation scheduling optimized:
Maize, wheat, boro, mungbean

46. Octocopter and satellite images to address the
spatial variability

47. Thank you! Questions?
u.schulthess@cgiar.org

48. Land suitable for technology targeting