Strengthening National Capacities for Sustainable
Resource Management in Latin America and the
Caribbean
CILCA 2011
COATZACOALCOS, Mexico April 7th, 2011
Part I
A comprehensive introduction to water
footprint accounting
This is a summary of the Water Footprint
Assessment Manual Earthscan 2011
by Maite Martínez Aldaya
The water footprint concept
► The WF is an indicator of water use that looks at both direct and
indirect water use of a consumer or producer.
► measured in terms of water volumes consumed (evaporated or
otherwise not returned) or polluted per unit of time.
► geographically and temporally explicit indicator.
► can be calculated for a process, a product, a consumer, group of
consumers (e.g. municipality, province, state or nation) or a producer
(e.g. a public organization, private enterprise).
[Hoekstra et al., 2011]
The water footprint components
Direct water footprint
Indirect water footprint
Blue water footprint
Blue water footprint
Grey water footprint
Grey water footprint
Water withdrawal
Return flow
The traditional
statistics
on water use
Water
pollution
Green water footprint
Water
consumption
Green water footprint
[Hoekstra et al., 2011]
Water footprint assessment
Phase 1
Setting goals
and scope
Phase 2
Water footprint
accounting
Phase 3
Water footprint
sustainability
assessment
Phase 4
Water footprint
response
formulation
[Hoekstra et al., 2011]
Water footprint unit
•
WF of a process: water volume per unit of time.
When divided over the quantity of product that results from the process, it
can also be expressed as water volume per product unit.
•
WF of a product: water volume per product unit. Examples:
•
o
water volume per unit of mass
o
water volume per unit of money
o
water volume per piece
o
water volume per unit of energy (food products, fuels)
WF of a consumer or business and WF within an area: water volume per
unit of time. The water footprint of a community of consumers can also be
expressed in terms of water volume per unit of time per capita.
[Hoekstra et al., 2011]
The water footprint
of a product
Water footprint of a product
► the volume of fresh water used to produce the product,
summed over the various steps of the production chain.
► when and where the water was used:
a water footprint includes a temporal and spatial dimension.
[Hoekstra et al., 2011]
Water footprint of a product
Green water footprint
► volume of rainwater evaporated or incorporated into product.
Blue water footprint
► volume of surface or groundwater evaporated, incorporated
into product or returned to other catchment or the sea.
Grey water footprint
► volume of polluted water.
[Hoekstra et al., 2011]
Grey water footprint
•
volume of polluted freshwater that associates with the
production of a product in its full supply-chain.
•
calculated as the volume of water that is required to assimilate
pollutants based on ambient water quality standards.
[Hoekstra et al., 2011]
Water footprint of products
global averages
1 kg wheat
1 m3 water
1 kg rice
3 m3 water
1 kg milk
1 m3 water
1 kg cheese
5 m3 water
1 kg pork
5 m3 water
1 kg beef
15 m3 water
[Hoekstra & Chapagain, 2008]
The water footprint of a cow
Food
► 1300 kg of grains
(wheat, oats, barley, corn, dry peas, soybean, etc)
► 7200 kg of roughages
(pasture, dry hay, silage, etc)
99%
Water
► 24000 litres for drinking
► 7000 litres for servicing.
1%
[Hoekstra & Chapagain, 2008]
[Hoekstra & Chapagain, 2008]
Water footprint
of a consumer
Water footprint of a consumer
► the total volume of water appropriated for the production of the
goods and services consumed.
► equal to the sum of the water footprints of all goods and
services consumed.
► dimensions of a water footprint
• volume
• where and when
• type of water use: green, blue, grey
[Hoekstra et al., 2011]
Water footprint of a consumer
Virtual
water
flow
Farmer
green grey
and water
blue
water
use
Food
processer
blue grey
water water
use
Indirect WF
Virtual
water
flow
Retailer
blue grey
water water
use
Virtual
water
flow
Consumer
blue grey
water water
use
Direct WF
[Hoekstra et al., 2011]
Water footprint of national consumption
► total amount of water that is used to produce the goods and
services consumed by the inhabitants of the nation.
► two components:
• internal water footprint – inside the country.
• external water footprint – in other countries.
► water footprint of national consumption =
water footprint within the nation + virtual water import
– virtual water export
[Hoekstra et al., 2011]
National water use accounting framework
Internal
water
footprint
+
External
water
footprint
+
Water use
for export +
The traditional
statistics on
water use, but
then limited to
withdrawals
Production
WF
within
nation
+
+
Virtual water
import for reexport
Virtual
water
export
=
=
+
WF of
national
consumpt.
Virtual
water
import
Consumption
Export
=
=
Virtual
water
budget
Import
=
=
[Hoekstra et al., 2011]
International virtual water flows
Virtual water flow (m3/yr) =
Trade volume (ton/yr)  Product water footprint (m3/ton)
Global trade data:
n
UN Statistics Division, New York
n
FAOSTAT, FAO, Rome
International virtual water flows (1997-2001)
Volume
(billion
m3/yr)
Percentage
(%)
Crops and crop products
Livestock and livestock products
Industrial products
987
276
362
61
17
22
Total
1625
100
= 16% of global water use!
[Hoekstra & Chapagain, 2008]
National virtual water balances
Net virtual water import (Gm3/yr)
-100 - -50
-50 - -25
-25 - -10
-10 - -5
-5 - 0
0-5
5 - 25
25 - 50
50 - 100
No Data
[Hoekstra & Chapagain, 2008]
Water footprint per capita
WFP(m3/cap/yr)
600 - 800
800 - 1000
1000 - 1200
1200 - 1300
1300 - 1500
1500 - 1800
1800 - 2100
2100 - 2500
No Data
[Hoekstra & Chapagain, 2008]
Water footprint per capita
3000
Domestic water consumption
Industrial goods
Agricultural goods
2000
3
Water footprint (m /cap/yr)
2500
1500
Global average water footprint
1000
500
USA
Italy
Thailand
Nigeria
Russia
Mexico
Brazil
Indonesia
Pakistan
Japan
India
China
0
[Hoekstra & Chapagain, 2008]
Global water footprint
contribution by consumption category
W ater footprint related to
consumption of industrial goods
W ater footprint related to domestic
water consumption
W ater footprint related to
consumption of agricultural goods
9.6%
85.8%
4.6%
Global water footprint = 7450 Gm3/yr
[Hoekstra & Chapagain, 2008]
Major determinants of the WF
1.
Consumption characteristics
- Consumption volume
- Consumption pattern
2.
Production circumstances
- Climate: evaporative demand at place of production
- Agricultural practice: water use efficiency
[Hoekstra & Chapagain, 2008]
The water footprint of a
business
Water footprint of a retailer
Virtual
water
flow
Farmer
green grey
and water
blue
water
use
Supply chain WF
Food
processer
blue grey
water water
use
Virtual
water
flow
Virtual
water
flow
Retailer
blue grey
water water
use
Operational WF
Consumer
blue grey
water water
use
End-use WF of a
product
The traditional statistics
on corporate water use
[Hoekstra et al., 2011]
Water footprint of a food processor
Virtual
water
flow
Farmer
Food
processer
Virtual
water
flow
blue grey
water water
use
green grey
and water
blue
water
use
Supply chain WF
Operational WF
Virtual
water
flow
Retailer
blue grey
water water
use
Consumer
blue grey
water water
use
End-use WF of a product
The traditional statistics
on corporate water use
[Hoekstra et al., 2011]
The Analysis of the
Tomato Footprint, Spain
Daniel Chico, Maite Aldaya,
Alberto Garrido, Gloria
Salmoral and Ramon
Llamas
A comparison of:
Chapagain, A. K. and Orr, S. (2009)
“An improved water footprint methodology linking global consumption to local
water resources: A case of Spanish tomatoes”
Journal of Environmental Management, 90.
Chico, D., Salmoral, G., Llamas, M.R., Garrido, A. and Aldaya, M.M. (2010)
"The Water Footprint and virtual water exports of Spanish Tomatoes"
Papeles del Agua Virtual n.º 8, Fundación Botín, 60 p. ISBN 978-84-96655-80-05
http://www.rac.es/2/2_ficha.php?id=119&idN3=6&idN4=40
Percentual comparison of WF (m3/t) for green and blue
water content in open-air irrigated and covered systems
Percentage variation
Open-air systems
Covered systems
m3/t
Almería
Granada
Málaga
Cádiz
Murcia
Tarragona
Barcelona
Gerona
Lérida
Guadalajara
Cuenca
Toledo
ciudad Real
Badajoz
Cáceres
Pamplona
Santa Cruz de Tenerife
Gran Canaria
Green
Blue
Green
Blue
110
35
45
38
59
32
35
144
81
83
38
41
58
35
43
21
50
109
58.7
158
92
144
109
191
323
323
519
238
379
662
147
268
151
174
361
62
107
244.9
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.0
181
212
206
165
188
299
335
509
167
Results Chapagain &
Orr
Results Chico et al.
X 100
Smaller in green water for open-air systems
as in Chapagain and Orr (average 60%)
Double blue water content both in open-air
irrigated and covered systems
These differences may be due to the
different data and assumptions,
0
0
415
86
118
205.8
specially concerning irrigation
schedule modelling.
Percentual comparison of WF of production for
selected regions and national average (1,000 m3/year)
Results Chapagain &
for green, blue and grey water
X 100
Orr
Results Chico et al.
Percentage variation
Green
Blue
Grey
3
23
9
20
201
55
345
3551
715
Castilla - LaMancha
11
53
484
Extremadura
18
23
3
24
15
71
400
35
56
61
575
2845
641
743
789
1.000 m3/year
Andalucía
Murcia
Cataluña
Navarra
Canarias
otros
Total
Significant differences by taking into account the yearly
productions and not averages
Much smaller green water, as well as blue water (with
exceptions)
Approach through Temporal analysis
Green, Blue and Grey WF in absolute terms (hm3), national
production and virtual water exported (hm3)
6000
1,200
5000
1,000
4000
WF (hm3)
800
3000
600
2000
400
1000
200
0
0
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
Average virtual water exported (hm3) , green and blue, and
National production ( 10^6 t)
1,400
NationalGrey
(hm3)
NationalBlue
(hm3)
NationalGreen
(hm3)
virtual water
exported
(hm3)
National
Production
(10^6 t)
2008
Increasing trend in WF associated to the increase in
the tomato production
Advanced WF
Economic analysis at current technology and market
standpoint
Av. Water apparent productivity per production
system (€/m3)
National Water apparent productivity (WAP, €/m3)
12
per production system
Av. Rainfed
WAP (€/m3)
10
8
Av. Irrigated
WAP (€/m3)
6
4
2
Av.
Greenhouse
WAP (€/m3)
0
1997
1998
1999
2000
2001
Share of National production (in tons)
Av. Water Apparent productivity (€/m3)
2002
2003
2004
Rainfed
0.003
2.10
2005
2006
2007
2008
Irrigated open-air
0.6
3.08
Greenhouses
0.4
7.78
Conclusions
•The estimations on consumptive use of water for crops have
usually a potential significant error
•The analysis of the economic water productivity is very important
from the practical point of view
•The results obtained for the water apparent productivity vary
significantly between years,
although the greenhouse production shows a significantly higher
productivity than irrigated open-air and rainfed production
Sources
Hoekstra, A.Y. and Chapagain, A.K. (2008) Globalization of water: Sharing the planet's freshwater
resources, Blackwell Publishing, Oxford, UK.
Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M. and Mekonnen, M.M. (2011) The water footprint
assessment manual: Setting the global standard, Earthscan, London, UK. Available from:
http://www.waterfootprint.org/downloads/TheWaterFootprintAssessmentManual.pdf
Morrison, J., Morikawa, M., Murphy, M. and Schulte, P. (2009) Water scarcity and climate change:
Growing risks for businesses and investors. Ceres, Pacific Institute. Available from:
http://www.ceres.org/Document.Doc?id=406
WFN (2011) Water Footprint Network. Available from: http://www.waterfootprint.org
3
Gracias !