Crop Water Productivity Mapping Using Remote Sensing and Secondary Data in the Nile Basin

Poolad Karimi

Addis AbabaNILE BFP midterm workshop

07 April 2009

Introduction

• Rapid increase in agricultural production will be required to keep pace with future food and fiber demands.

– This can be achieved by bringing more area under agriculture or

– by increasing the yields using similar or even reduced water resources (e.g., increasing productivity of water).

• Considering that:– Land and water resources are already reached their exploitation limits or are

over exploited in many river basins; and

– There is increasing competition for water among sectors.

• The option of increasing agricultural production using same or less water resources is the most appropriate one.

Water productivity mapping:METHODOLOGY

nConsumptio

BenefitWP

(Molden 1997)

MODIS-TERRA 1000m

MODIS-TERRA 250m NDVI time series

SRTM 90m DEMSub-catchmentBoundaries

Land Use Land CoverMap

Estimation of Actual Evapotranspiration ETa

Administrative/districtmaps and agricultural statistics

Meteorological Data

Image Classification

Topographic/ GIS Analysis

Energy Balance Analysis

Land use wise sub-catchment Actual Evapotranspiration ETa

Land use wise sub-catchment Gross Value of Production (GVP)

Sub-catchment level Land use type

Water Productivity(GVP/ETa)

MODIS-TERRA 1000m

MODIS-TERRA 250m NDVI time series

SRTM 90m DEMSub-catchmentBoundaries

Land Use Land CoverMap

Estimation of Actual Evapotranspiration ETa

Administrative/districtmaps and agricultural statistics

Meteorological Data

Image Classification

Image Classification

Topographic/ GIS Analysis

Topographic/ GIS Analysis

Energy Balance Analysis

Energy Balance Analysis

Land use wise sub-catchment Actual Evapotranspiration ETa

Land use wise sub-catchment Gross Value of Production (GVP)

Sub-catchment level Land use type

Water Productivity(GVP/ETa)

Source: IWMI, 1997

• Land use and land cover map : Global Cover Land Cover 2008 by European Space Agency: Its 22 land cover global classes are defined with the UN Land Cover Classification System (LCCS). The product pixel size is 300m. Croplands clases in the map are as fallows:

- Post-flooding or irrigated croplands (or aquatic)

- Rainfed croplands

- Mosaic cropland (50-70%) / vegetation (grassland/shrubland/forest) (20-50%)

- Mosaic vegetation (grassland/shrubland/forest) (50-70%) / cropland (20-50%)

Doesn't give us Crop type map

• IFPRI1 production maps

IFPRI1: International Food Policy Research Institute

• Actual evapotranspiration (ETa): Water watch ET map for 2007 (Wim/Yasir). The map pixel size is 1Km.

• Secondary administrative agricultural statistics - Ethiopia : Central Statistical Agency (CSA)

- Sudan: Sudan Central Bureau of Statistics

How can we get the same data for other countries particularly Egypt ?

Crop water productivity in Ethiopian part of the Nile Basin

Source: Created by Karimi,P.

Rainfall and Water Consumption in 2007

• Precipitation:• 1043 mm

• Average ETa:• 730 mm

• Overall Crop GVP:• 4.4×109 $/year

Source: Created by IWMI using data from FEWS, 2009 Source: Created by IWMI using data from Waterwatch, 2009

Crops water consumption and economical land productivity

• Eta Crops: 4500 m3/ha;

1542 m3/ha to 7500 m3/ha

Eta per ha is lower in the eastern part

• Crop GVP: 540 US$/ha

286 US$/ha to 822 US$/ha

• High performing areas in terms of Crop GVP/ha are:

- Shaka, Benchi Maji, Jimma and West Gojam

Source: IWMI, 2009 Source: IWMI, 2009

Sub-Basin to Basin Scale Analysis:WP of vegetative and livestock

• Crop WP: 0.16 $/m3; 0.004 to 0.30 $/m3.

– The higher values are mainly due to higher proportion of irrigated lands

• Agricultural economic water productivity is higher in the eastern part

• could it be due to high evaporation in cropped area and not transpiration in western part??

Source: IWMI, 2009

Crop water productivity in Sudanese part of the Nile Basin

Total cropped area:

Secondary Stat: 14,860,440

GLC: 12,298,145

FAO: 12,849,520

Source: IWMI, 2009

Crop GVP VS Livestock GVP

-Growth of livestock production value in last years-Importance of Livestock in Water productivity calculation

Source: Graphs created by Karimi, P using data from FAO

• Secondary statistical data together with remote sensed data could be used to Map economic water productivity but it depends on how accurate are they.

• Getting IFPRI Production maps seems to be very crucial to evaluate these result also to use to produce spatial distributed WP map for entire Nile

• Use of Biomass to get physical WP and try to convert it to economical WP - it needs a crop type map and accuracy of results would be highly dependent on accuracy of the crop type map

• How to join livestock WP and Fisheries WP with crop water productivity to create an overall water productivity map?

Summary ,Conclusionsand Questions

Related Project Report Forthcoming.

For more information visit:

www.iwmi.org

www.waterandfood.org

N.B. This is not a form of technical output. Data and figures shown are subject to change.