G1 Extrapolation domains and land use plans for the coastal zone of Bangladesh

G1 partners5th May 2014

Extrapolation domains and land use plans for the

coastal zone of Bangladesh

IWM LGED IRRI SRDI BWDB

“What works where?”

“Area, people, livelihoods”

“data, data, data”

G1 in three words

Andy IntroductionSohel Census data, infrastructure and mouzasNasim Water, drainage and storageParvesh Land use/land cover and extrapolation domainsAndy Sharing results and what next?

Outline

OutputsTarget area for extrapolation domainsBest bet options in coastal Bangladesh

OutputsTarget area for extrapolation domainsCoastal polders cover 1m ha

OutputsTarget area for extrapolation domains

High saline - Polder 3Rice/shrimp &Aquaculture

Moderately saline - Polder 30 – Usually one crop per year

Low saline - Polder 43/2f

Up to two crops per year

The coastal zone in a nutshell

This zone covers:• 1.45m farm holdings, 10% of the national total• 7.3 million people and 2m laborers, many of them

poor• Irrigated area is 25%, national average is 68%• HYV rice area 24%, national average is 56%• Cropping intensity is very low compared to the

national average.• The coastal zone is one of few areas in Bangladesh

where productivity and intensity can be significantly increased.

It is a zone with huge potential, but where exactly is that potential? And then, how to unlock it?

Best bet options in coastal Bangladesh

Suitable areas for innovative cropping systems?Spatial analysis of suitability factors/constraintsHow will this change in future?Impact of future scenarios on factors/constraintsHow can we inform stakeholders about the opportunities?Improved dissemination/sharing of information

High resolution land use maps “What is the current land use?”Cropping system extrapolation domains “What works where? Now and in the future”Southwest Coastal Region Information System“Open access spatial data - webGIS”

G1 Outputs and Aims

• Emphasis on collecting and developing the best possible datasets.

• Emphasis on both spatial AND temporal data to represent the different requirements of the cropping systems through the year. Especially for water.

• Emphasis on making our spatial data freely available.• Looking to the future – where and when can these same

methods and data be used to address other research questions?


Outline

Activities carried out by LGED

1. Preparation of Different layers of base information:

Different layers of administrative boundary and Head quarter including Mouza Boundary (Smallest boundary layer)

Road Network (up to village road)Growth Center and Rural Market Facilities River Network and Water Body Data

2. Preparation of Mouza wise Socio-economic information

Road Network: Accessibility to remote area Growth Center and Rural Market: facilities for rural people

for economic development

The Map shows the River Network and water body: data generated from RapidEye satellite image (2011)

Development of Lowest boundary layer (Mouza Boundary)

Map of Mouza Layer (Polder 3)

Mouza wise 2008 Agricultural census data layer

Mouza wise 2008 Agricultural census data layer


Outline

May, 2012

Base Year: 2012

KHULNA

BARISAL

Spatial and Seasonal Variation of Salinity in the Coastal Ganges in Bangladesh

Digital Elevation Model (DEM) of the Coastal Area

Kharif-1 Kharif-2 RabiAvg WL 1.00m PWD

Avg WL 1.30m PWD

Avg WL 0.80m PWD

Opportunity for Gravity Drainage & Gravity Irrigation

1.35 mPWD Avg WL

1.84 mPWD High WL with 3hr tidal window for Irrigation

0.90 mPWD Low WL with 3hr tidal window for Drainage

Gravity Drainage

Gravity Irrigation

Gravity Irrigation


Outline

Existing Land use in Coastal Districts of Barisal and Khulna

Divisions

Existing Land use/Cropping System

- Data used, Material and Methods

- Results : Examples of major cropping system

- Assessment of water regimes using improved indices

- Next Steps

Extrapolation Domains

- Data used, Material & Methods

- Results : examples of existing and improved cropping systems

- Next Steps

Socio-economic Indices

- Potential Technology Adoption Index

- Livelihood Index

Data gaps, Next Steps

Contents ….

Satellite data used : IRS Resourcesat – LISS III, 23 M resolution

Pass/Row covered : 109-56 & 110-56

GPS Ground Truth : 3 times and collected more than 1000

pictures

Time : October 2011 to May 2012

Image Processing : Radiometric correction (using PIFS) & pre-

processing Image classification : Spectral Temporal NDVI

profiles, Decision rules, associations

Post classification procedures & accuracy assessment

Existing Land use: Datasets and Material & Methods

Satkhira

Khulna

Bagerhat

Narail

Sunderban

Aman Rabi Aus

Nov Jan Feb Mar Apr May

Aman Boro


Aman-Rabi-Aus

Aman-Boro

Aman-Rabi crop

Shrimp-Aman

Aman-Fallow

Water Bodies/Ghers

Settlements

Major land use Classes

Existing Land use in 4 coastal districts of Khulna division : mainly for Aman and Boro season

Existing Land use, Khulna division

Harvest

Planting

Harvest Harvest

Planting

Planting

Overall accuracy assessment = 86%

Fallow Boro

Nov Feb Mar Apr

Aman-Rabi/Legumes/br

Fallow - Boro

Aman-Fallow

Water Bodies

Settlements

Major land use Classes

Barisal

Bhola

Patuakhali

Berguna

Jhalakati

Existing Land use in 5 coastal districts of Barisal division : Aman and Boro season only

Aman Fallow

Nov Feb Mar Apr

Waterlogged

No Water

Planting

Harvest

Overall Accuracy = 89%

Existing Cropping Systems of Barisal division Existing Land use: Results

1. Water will have greater positive values than in the NDWI as it absorbs more MIR light than NIR Light

2. Built-up land will have negative values as mentioned above;

3.Soil and vegetation will still have negative values as soil reflects MIR light more than NIR light

Improved Normalized Water Difference Index: Seasonal Change in water regimes

Nov, 2011 Feb, 2012

Mar, 2012 Apr, 2012

Shallow Depth

Medium Depth

Deep Water

Water RegimesVery Shallow Depth/ Excessive moist

Existing Land use: Results

Nov Jan Feb Mar Apr May Nov Jan Feb Mar Apr May


Can we estimate water depth/water availability in Khals?Existing Land use: Results

Extrapolation Domains

Study Area

Material and methods

1 Expert assessment of the requirements for each cropping system.2 Identification and collection of data that either measure or act as proxies for those requirement.3 Suitability scores based on location specific characteristics relative to the cropping system requirements.4 Suitability maps for each cropping system.5 Review and revise maps with focus groups.

Characterize the cropping systems

Aman - RabiTraditional Aman rice is transplanted in Aug and harvested in Dec/Jan. Aman rice is almost entirely rain fed and uses local varieties that can withstand flood depth to 0.8 m. The Rabi crop (e.g. sesame, moonbeam) is seeded in Feb-Mar and harvested in May-Jun. The Rabi crop uses residual soil moisture with supplemental irrigation when ground water or (stored) canal water is available. Rainfall at the end of the rabbi season can negatively affect the crop, thus good surface drainage is important.

We start with a narrative…

Taos HYV - Aman HYV - Boor HYV A short duration Aus HYV is seeded in early April, transplanted in late April and harvested by end of July. The Aus crop uses seedbeds and land preparation and is irrigated when river water is fresh, with groundwater (GW) or from canal water. In this case, capacity of gravity irrigation is considered. Short duration, non photoperiod sensitive Aman HYV is transplanted by first week of August and harvested by the end of November. The Aman rice crop is completely rain fed. Its performance depends greatly on maximum inundation depth/land topography. When inundation depth > 0.4 m, drainage capacity must be considered. This, in turn depends on the difference between land elevation and the water levels at low tides and distance from canals/rivers. Boor HYV is transplanted before mid December and harvested by mid April. The Boor rice crop is irrigated with GW or river water (when fresh) or with water stored in canal networks. When river water is fresh, the ability to irrigate by gravity is considered. Storage capacity is considered when stored water is used. Distance from water source is considered in both cases.

Some are quite complex…

…a lot of data needed

Irrigation with GW

1 Fresh (< 4dS/m) ground water availability 2 Ground water pumping depth

Irrigation with SW

3 Latest month when river water <3 dS/m 4 Maximum river water salinity in April/May 5 Maximum river water salinity in August 6 Difference in high water level in April and land surface for gravity irrigation 7 Difference in high water level in March and land surface for gravity irrigation

8 Difference (m) in land surface and high water level in Mar/Apr for irrigation 9 Storage capacity 10 Proximity to river, canal, ponds, for irrigation

Drainage

11 Proximity to river, canal, for drainage 12 Maximum inundation depth/land type 13 Maximum inundation depth for > three days in May 14 Maximum inundation depth in September/October 15 Maximum inundation depth for > one week in September/October 16 Maximum inundation depth for > two weeks in September/October 17 Difference in land surface and low water level in May for drainage 18 Difference in land surface and low water level in September/October for drainage

Soil 19 Soil texture 20 Soil pH 21 Soil salinity

gher water 22 lowest water salinity during January and highest during April (ppt) 23 Inundation depth/land type

Climate

24 Weekly air minimum temperature at stocking 25 Weekly mean minimum air temperature in January 26 Two-week mean air temperature in December and January 27 Cumulative rainfall in July & August

Social and economic

28 Livelihood/asset index 29 Technology adoption index

Extensive Gher based year round brackish water aquaculture

Description

Minimum air temperature

for 1week (C)

Minimum salinity (ppt)

at PL stocking

Land type / Inundation

depth

Soil texture

Acidity (pH)

Shrimp PL is stocked in Feb when there is brackish water adequate and

suitable temperature,

brackish water Fish is stocked

few weeks later. Water is

replenished as needed. Harvest

starts after 2 month until end

of Nov.

>25 S1 >10 S1 0.5 - 0.7 S1clay Loam

S16.5 - 7.5

S1

20 - 25 S2 5 to 10 S20.7- 1; 0.3 - 0.5

S2Loam

S15.5 - 6.5; 7.5 - 8.5

S2

18 -20 S3 2 - 5 S31 - 1.2; 0 - 0.3

S3Sand

y loam

S24.5 5.5; 8.5 - 9.5

S3

<18 SN <2 SN> 1.2; no inundation

SNSand

ySN

<4.5; >9.5

SN

S1 = Most Suitable S2 = Suitable S3 = Marginally Suitable SN = Not Suitable

Requirement for aquaculture

Aman - Boor Water quality and availability in dry season

Description of Land use type(technology)

Fresh (< 4dS/m),

ground water availability

and pumping depth

Month when river water still

remain fresh

(<4 dS/m)

Internal storage

capacity in relation to land area(ML/ha)

Proximity to river, canal,

ponds (m)

Difference (m) in high water level in Mar and

land surface for

gravity irrigation

(m)

Boor rice is seeded around 15 Nov. (MS) to 15 Dec (LS). Aman rice is rain fed. Boor rice is irrigated with river water (when fresh) or with water stored in canal networks.

Yes, < 6 m

S1 March S1 > 5 S1 <50 S1 > 1 S1

Yes, 7 -20 m

S2 Feb S2 2.5 - 5 S2 50-100 S2 0.5 - 1 S2

yes, > 20 S3 Jan S3 1 - 2.5 S3100-300

S30.2 - 0.5

S3

No SN Dec SN <1 SN >300SN

< 0.2 SN

Aman - Boor Water quality and availability in wet season

Description of Land use

type(technology)

Maximum inundation depth (m) in August

Maximum inundation depth (m) for more than one week in

Sep/Oct

Difference (m) in land surface and low water level in

Sep/Oct for drainage

Aman HYV rice is transplanted in July-August, to be harvested by the end of November (Moderate Salinity zone) or December (low saline zone).

< 0.1 S1 < 0.2 S1 > 1 S1

0.1 – 0.2 S2 0.2 – 0.5 S2 0.5 - 1 S2

0.2 – 0.3 S3 0.5 – 0.8 S3 0.2 – 0.5 S3

> 0.3 SN > 0.8 SN < 0.2 SN


Water requirements for Aman - Boor

Fresh groundwat

er (< 4dS/m)

Tubewell?Tubewell depth

(m)

Month when river water (< 3

dS/m)

Storage capacity (ML/ha)

Proximity to fresh SW source (m)

Suitability for HYV

Boor rice crop

Yes

No

Shallow

Deep

< 6

7 - 20

Mar

Feb

Jan

Dec

> 20

2.5 - 5

1- 2.5

2.5 - 5

1 – 2.5

< 100

> 100

< 100

> 100

< 100

> 100

< 100

> 100

S1

S1

S2

S3

S1

S1

S2

S2

S3

S2

S3

S3

SN

SN

Groundwater Surface water

Soil pH Soil texture

Min temp – 8th-14th Feb Soil salinity Water salinity

Example: Input datasets

Flood inundation depth

Values in percent

Percentage of small farms, <1ha

Percentage of leased land

Through our partners we have obtained the 2011 population and 2008 agricultural census’ at village level. This is a huge and still untapped resource.

Example: Input dataset

Existing system for validation(1)Aman – Rabi crop(2)Aus - Aman(3)Aman - Shrimp(4)Year round aquacultureInnovative systems for targetting(5)Aman (HYV) - Rabi (HVC)(6)Aus – Aman - Boor(7)Aus - Aman - Rabi crop(8)Boor - Aman(9)Aus (HYV) – Aman (HYV)(10) Year round polyculture(11) Shrimp - RiceEach one can be mapped as present and conditional system

Proposed number of domains to map


Year Round Aquaculture



Criteria and parameters for developing extrapolation domains

Inundation Depth Soil pH Soil Texture

Min Temp – 2nd week of Feb and March Max water Salinity levels


Results …

Results

0-7 days - Feb 7-15days - Feb

21-30 days - Feb

15-21days - Feb

Extrapolation domains/suitable areas for Pl stocking

0-7 days - Feb 7-15days - Feb 15-21days - Feb0-7 days - Feb 7-15days - Feb

21-30 days - Feb

15-21days - Feb0-7 days - Feb 7-15days - Feb

0-7 days - March

Results existing systems …

Results …

Areas Suitable for Shrimp Cultivation


Marginally suitable = Dark Green Suitable = Light Green Most suitable = Purple Not suitable = Yellow

Results …

Areas Suitable for Aman Rice Cultivation

Results exiting systems …



Suitability for Shrimp-Aman Cultivation

ShrimpAman Rice

Shrimp-Rice


Results Improved systems…

Not Suitable

Marginal Suitable

Marginally suitable = 330,000 haSuitable area = 180,000 ha

Results Improved systems…

Extrapolation Domains : Aus (HYV)-Aman (HYV)-Rabi cropping system

Not SuitableMarginal Suitable

Marginally suitable = 500,000 haSuitable area = 16,000 ha

Results …

Shrimp TAus Aman

Shrimp-Aman

Aman

Ex. Domains at Polder Level


Part 3: Socio-economic Indices

Low (< -0.5)

Medium (-0.5 to 0.5)High (0.5 to 1.5)

Range of Composite Standard Score/Z Score

Very High (>1.5)

Polder 30, District Khulna

Technology Adoption Index at Mouza Level

Polder 3, District Satkhira

Results …data gaps

1. Generalized soil salinity map (2009)

2. Detailed Salinity Map (2009) which I have prepared using the actual survey data of EC from SRDI


Outline

WebGIS – http://gangesriverbasin.blogspot.com

• Remote sensing can be used to map seasonal rice area for all Bangladesh

• Can assess changes in cropping intensity from year to year and monitor flood extent

• Seasonal rice maps will be freely available on the webGIS

[email protected] for a copy of the paper

Key messages

1 Big potential for sustainable, increased productivity and

improved livelihoods in the coastal zone of Bangladesh

2 Based on research findings from Ganges Basin Development

Partnerships

3 Institutional data sharing has been key to developing new,

detailed maps that show the potential land use and the

potential scale of livelihood improvement

4 Our webGIS is one way to ensure the data remains open &

free

Where next in 2014/15?

1. Assess the impact of salt tolerant varieties using the extrapolation domain methodology. How many people could benefit from innovative systems that include current and future stress tolerant varieties?

2. Assess the impact of improved drainage using the same method. How many people would benefit from infrastructure renovation/improvement for increased productivity?

3. Assess changes in land use under G4 scenarios. What are the implications for land use planning in the coastal zone?

Where next in 2014/15?

4. Share spatial data results as widely as possible. What are the key research questions in the coastal zone and elsewhere? How can the methods be adopted to address them? What expertise is needed to do this?

5. Launch of the WebGIS. Still need to address who will sustain the webGIS and the spatial data it hosts?

Thank you

IWM LGED IRRI SRDI BWDB

Environment

G1 Extrapolation domains and land use plans for the coastal zone of Bangladesh