Presented at the Basin Focal Project Review meeting in Cali, Colombia from 1-5 Feb, 2008

1. Water productivity
Francis ‘n’ Simon

2. Purpose
Method
Progress
Problems
P bl
Prospects

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

4. Simplify, then exaggerate
Simplify

5. Complicate, simplify, then
exaggerate

6. Complicate, simplify,
complicate again….

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

8. Fascinating stuff

9. WPr: A basic measure of
performance
Benefit gained per volume water
used

10. Rationale for increasing water
productivity
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 rationale
– Increase water availability to all
– Reduce investment in water resources
– Increase total benefits (variable) from water use (constrained).
Water system level rationale
y
– Secure water for tail=end water users
– Reduce O&M costs
– Comply with water permit and pollution regulations
Water users level rationale
– Expand i i t d area
E d irrigated
– Reduce water costs
– Increase agricultural output, food security and profitability
Note: Trade-offs and synergies across scales

11. Method [grossly simplified]:
[g y p ]
– Define (sub) system
– Estimate gain
g
– Estimate water use
– Divide gain/WU
g /
– Portray as
• Tables
• Maps
• Graphs
– Interpret …[more later]

12. Estimating WPr
g
For an area…
Gain Consumption
– Yield, t, Price – Rainfall ~~ ET
• Direct measure – Water balance
• Secondary data
y
estimates
• Remote sensing
estimates – Crop ET
– Corrections estimates (eg
SEBALS, SEBS)

13. Progress
g
More crop per drop (WUE)
Kgcrop/m3water
– Irrigated crops
– Rainfed crops
$/m3, SGVP; multiple crops
Livestock WPr….[close]
Fish WPr …[not so close]
[not
Marginal WPr…[too hard]
Relative WPr [dubious utlity]
WPr….[dubious
Multi-sector valuation…[too hard?]

14. Change (or lack of it)
through time
thro gh
0.800
Laos
3
productivity, kg/m
0.800
response Laos
Water ductivity, kg/m3
0.600 Thailand
WP
k
0.600
0 600 Thailand
0.400 Cambodia
0.400 Cambodia
Vietnam
Water prod
0.200
Vietnam
0.200
crisis Vietnam Central
highlands
0.000 Vietnam Central
highlands M k
hi hl t
Vi d
Vietnam Mekong
0.000
1990 1995 2000 2005
River Delta
Vietnam Mekong
timeDelta
1990 1995 Year 2000 2005
River
Year

15. WP variation raises
questions
Maize WPr
Volta

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

17. WPr Gap
p
After FAO

18. Relative WP

19. Sometimes there appears an association
Data sometimes shows association

20. Mapping Partial Water
Productivity
y
0.2-0.4
0204
1.2 1.6
1 2-1 6
0.8-1.2
0 8-1 2
0.6-0.8
0.4-0.6
Water productivity
in rice – in kg / cubic meter of Et
Frank’s Dream

21. Problems:
Estimation
Interpretation

22. Estimation
– 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
• Pollution [usually not accounted] Aim: to increase total
benefit [per person] / total consumption

23. Problem:
Many different indicators and units
y Output parameter
Physical measures Physical/economic Economic
Water input parameters measures measures
(
(m3 or $ value)
) Biomass Harvestable Gross Net Gross Net
yield value value value value
(kg)
($)
(kg) ($) ($) ($)
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 $/m3 ($/$) ($/$)

24. Multiple gains in complex
agricultural systems
agric lt ral s stems
Some agricultural production systems and their benefits.
Agricultural Benefits
production system Primary goods Secondary goods Services
Soil cover to reduce
Crop residue for
p erosion, enhancing agro-
, g g
Crop production
C d ti Harvestable yield
H t bl i ld
livestock feed biodiversity, carbon
sequestration
Draft power, manure,
Livestock production Meat, milk and eggs
leather
Bio-diversity, water
catchment protection,
Tree production Timber, fuel wood Food
carbon sequestration
Bio-diversity of aquatic
Fish production Meat Manure
ecosystems

25. Problems of interpretation
p
A partial & comparative measure
of performance
p
• 0.2 kg/m3 = bad; 0.8 kg/m3 = bad
• An accounting variable
• Maximize total gain /m3 consumed
• But is water the important factor?

26. Final thoughts
g
(Meike’s slides)