Water productivityWater productivityWater productivityWater productivity

Francis ‘n’ Simon

PurposeMethodMethodProgressP blProblemsProspects

…it all seemed so simple …it all seemed so simple when we started…when we started…

Simplify then exaggerateSimplify then exaggerateSimplify, then exaggerateSimplify, then exaggerate

Complicate, simplify, then Complicate, simplify, then exaggerateexaggerate

Complicate, simplify, Complicate, simplify, complicate again….complicate again….

Complicate, simplify, complicate simplify Complicate, simplify, complicate simplify complicate, simplify

again….complicate, simplify

again….

Fascinating stuffFascinating stuffFascinating stuffFascinating stuff

WPr: A basic measure of WPr: A basic measure of WPr: A basic measure of performance

WPr: A basic measure of performance

Benefit gained per volume water used

Rationale for increasing water productivity

Rationale for increasing water productivityproductivityproductivity

Global imperative– Meet combined targets of food and water security– CPWF target - “maintaining the level of global diversions of water, while

increasing food production”Basin level rationaleBasin level rationale

– Increase water availability to all– Reduce investment in water resources– Increase total benefits (variable) from water use (constrained).

Water system level rationaley– Secure water for tail=end water users– Reduce O&M costs– Comply with water permit and pollution regulations

Water users level rationaleE d i i t d – Expand irrigated area

– Reduce water costs– Increase agricultural output, food security and profitability

Note: Trade-offs and synergies across scales

Method [grossly simplified]:Method [grossly simplified]:[g y p ][g y p ]

– Define (sub) system– Estimate gaing– Estimate water use– Divide gain/WUg /– Portray as

• Tables• Maps• Graphs

– Interpret …[more later]Interpret …[more later]

Estimating WPrEstimating WPrggFor an area…

Gain Consumption– Yield, t, Price

• Direct measure• Secondary data

– Rainfall ~~ ET– Water balance

estimatesy• Remote sensing

estimates

– Corrections

estimates– Crop ET

estimates (eg SEBALS, SEBS)

ProgressProgressgg

More crop per drop (WUE)Kgcrop/m3

water – Irrigated crops – Rainfed crops$/m3 SGVP; multiple crops$/m3, SGVP; multiple cropsLivestock WPr….[close]Fish WPr [not so close]Fish WPr …[not so close]Marginal WPr…[too hard]Relative WPr [dubious utlity]Relative WPr….[dubious utlity]Multi-sector valuation…[too hard?]

Change (or lack of it) thro gh time

Change (or lack of it) thro gh timethrough timethrough time

0.800

0 600

0.800

kg/m

3 LaosresponseWP

0.600

ity, k

g/m

3 Laos

Thailand

0.400

0.600

duct

ivity

, k Thailand

Cambodia

WP0.400

prod

uctiv Cambodia

Vietnam

0.200

Wat

er p

rod

Vietnam

Vietnam Centralhi hl d

crisis0.000

0.200

Wat

er

Vietnam CentralhighlandsVi t M k0.000

1990 1995 2000 2005

Year

highlandsVietnam MekongRiver Deltatime

1990 1995 2000 2005

Year

Vietnam MekongRiver Delta

WP variation raises

Maize WPrquestions

Volta

Water and agricultural production determinants as entry points for identifying intervention opportunities

Water and agricultural production determinants as entry points for identifying intervention opportunitiespoints for identifying intervention opportunitiespoints for identifying intervention opportunities

WPr GapWPr Gappp

After FAO

Relative WP

Data sometimes shows associationSometimes there appears an association

0 2 0 4

Mapping Partial Water Productivity

0.2-0.4

1 2-1 6

y

0 8-1 2

1.2 1.6

0.6-0.8

0.8-1.2

0.4-0.6

Water productivity in rice – in kg / cubic meter of Et

Frank’s Dream

Problems:Problems:

EstimationInterpretationInterpretation

EstimationEstimation

– Benefit • Difficult to estimate amount

– Areas don’t match, yield data uncertain, partial, etc• Worse to interpret

– Who gains? What value?

– Consumption• ET very difficult to assess• Water that flows through is not consumed• Water that flows through is not consumed• Pollution [usually not accounted] Aim: to increase total

benefit [per person] / total consumption

Output parameter

Problem: Many different indicators and units

Physical measures Physical/economic measures

Economic measures Water input parameters

(m3 or $ value) Biomass Harvestable Gross Net Gross Net

y

( )

(kg) yield

(kg)

value

($)

value

($)

value

($)

value ($)

Gross inflow kg/m3 kg/m3 $/m3 $/m3 ($/$) ($/$)Gross inflow kg/m3 kg/m3 $/m3 $/m3 ($/$) ($/$)

Net inflow kg/m3 kg/m3 $/m3 $/m3 ($/$) ($/$)

Available water kg/m3 kg/m3 $/m3 $/m3 ($/$) ($/$)

Depleted water kg/m3 kg/m3 $/m3 $/m3 ($/$) ($/$)

Beneficially depleted water kg/m3 kg/m3 $/m3 $/m3 ($/$) ($/$)

Process depleted process water kg/m3 kg/m3 $/m3 $/m3 ($/$) ($/$)Process depleted process water kg/m3 kg/m3 $/m3 $/m3 ($/$) ($/$)

Multiple gains in complex agric lt ral s stems

Multiple gains in complex agric lt ral s stemsagricultural systemsagricultural systems

Some agricultural production systems and their benefits.BenefitsAgricultural

production system Primary goods Secondary goods Services

C d ti H t bl i ld Crop residue for Soil cover to reduce erosion, enhancing agro-Crop production Harvestable yield p

livestock feed , g g

biodiversity, carbon sequestration

Livestock production Meat, milk and eggs Draft power, manure, leather leather

Tree production Timber, fuel wood Food

Bio-diversity, water catchment protection, carbon sequestration

Fish production Meat Manure Bio-diversity of aquatic ecosystems

Problems of interpretationProblems of interpretationpp

A partial & comparative measure of performancep• 0.2 kg/m3 = bad; 0.8 kg/m3 = bad

• An accounting variable • An accounting variable • Maximize total gain /m3 consumed• But is water the important factor?• But is water the important factor?

Final thoughtsFinal thoughtsgg

(Meike’s slides)