Transcript Making Better Energy Choices

Boosting Water
Productivity
Sandra Postel and Amy Vickers
State of the World 2004
Boosting Water Productivity
Overview:
1. A New Mindset for Managing Water
2. Water-Rich, Water-Poor
3. Water, Crops, and Diets
4. Cities and Homes
5. Industrial Water Use and Material
Goods Consumption
6. Policy Priorities
Freshwater Ecosystems
• Rivers, lakes, wetlands, and
underground aquifers
• They store, move, and
cleanse water as it cycles
between sea, air, and land
• Healthy ecosystems need
- Minimum quality and quantity
of water
- Natural flow pattern
World Water Use
Industry
(22%)
Agriculture
(70%)
Towns and
Municipalities
(8%)
Source: World Bank, World Development Indicators, 2001
Human Influences on
Freshwater Ecosystems
• Water tables are falling
from overpumping of
groundwater
• Many streams and rivers
run dry for portions of the
year
• Large inland lakes are
shrinking
• World’s freshwater wetlands
have diminished in area
by half
Current Water Use Patterns
Are Unsustainable
• Impacts accelerate with increases in population
and consumption
• Large-scale water development projects (i.e.,
dams, reservoirs, diversion projects) have
social and ecological costs:
- Ecosystems destroyed
- Fisheries decimated
- Aquatic species imperiled
- People displaced from
their homes
1. A New Mindset for
Managing Water
• Freshwater is a life support system for
ecosystems
• Must allocate sufficient water throughout the
year to protect valuable ecosystem functions
• Can use remaining water to satisfy human
demands efficiently, equitably, and productively
Water Productivity of
Selected Countries
Water Productivity: Value of economic goods and
services per cubic meter of water extracted from the
natural environment
Egypt
India
China
Russian Federation
United States
Brazil
Australia
2.8
3.6
8.5
12.3
18.0
20.3
21.3
40.2
Germany
Source: FAO, USGS, OECD
GDP per cubic meter of water use (2000 dollars)
2. Water-Rich, Water-Poor
• Uneven distribution of water on a global scale
- 6 countries (Brazil, Russia, Canada, Indonesia, China,
and Colombia) account for half of Earth’s freshwater
supply
• Water-poor areas have higher demands
because crop production requires more
irrigation in drier climates
Estimated Annual Water Withdrawals
Per Capita, Selected Countries (2000)
Ethiopia
Brazil
Russian Federation
India
Egypt
42
348
527
640
1011
1932
United States
Source: FAO, USGS
Cubic Meters Per Person Per Year
Affluence and Poverty
• Influence of power, politics, and money
can override natural abundance or scarcity
of water
Phoenix, Arizona: Desert
climate, but imports water
from Colorado River
Ethiopia: 84% of the Nile’s
flow originates within its
territory, but faces famine
due to drought
Populations Lacking Access to Safe
Drinking Water and Sanitation (2000)
1 out of 5 people in developing world
(1.1 billion people) face risk of disease and
death due to lack of access to safe drinking water
Region
No Safe
Drinking Water
No Adequate
Sanitation
Africa
36%
40%
Asia
19%
53%
Latin America &
Caribbean
13%
22%
Source: World Health Organization
Meeting Basic Needs
• Urgent task: to provide all people with
minimum amount of clean water needed
for good health and sanitation
• More than enough water to accommodate
everyone’s basic needs but political will
and financial commitment lacking
• When private corporations manage water
systems, cost-recovery can take priority
over meeting basic needs
3. Water, Crops, and Diets
Must raise productivity of agricultural water use
to meet growing food needs as water stress
deepens and spreads
Three Challenges:
• Delivering and applying water to
crops more efficiently
• Increasing yields per liter of water
consumed
• Shifting diets to satisfy nutritional
needs with less water
Water, Crops, and Diets
• Surface water irrigation efficiency is
typically poor (can be as low as 25-40%)
• Losses due to leaks, seepage, evaporation
Improving Irrigation Efficiency
Micro-irrigation methods
- drip and micro-sprinklers reduce
volume of water applied to fields
by 30-70% and increase crop
yields by 20-90%
Changes in cropping patterns and
growing methods
- using high-yielding and earlymaturing crop varieties
- deficit irrigation: only watering
plants during critical growth stages
Improving Irrigation Efficiency
Affordable technologies for small plots
- ex.: treadle pumps: human
powered devices that give access
to shallow groundwater
Collecting and storing rainfall
- using ponds, check dams, and
other structures to irrigate crops
during dry season, recharge
groundwater
Dietary Choices
5000
Liters of Water
4902
Water consumed to supply 10g of protein
Water consumed to supply 500 calories
4000
3000
1515
2000
421
89
1000
0
67
potatoes
potatoes
251
219
132
135
beans
beans
w
heat
wheat
204
rice
rice
1000
303
poultry
poultry
beef
beef
Based on California crop yields and water productivity. Source: Renault and Wallender (2000)
Dietary Choices
• Average U.S. diet, high in
meat content, requires twice
as much water as an equally
nutritious vegetarian diet
• Cutting consumption of animal products in half
would reduce:
-
nation’s dietary requirements of water by 37%
incidence of heart disease
cruelty to animals
pollution of streams from industrial animal feedlots
4. Cities and Homes
• Waste is a major urban water management
problem
• In many cities, water losses are 15% - 40%,
some higher
• Unaccounted-for Water (UFW): volume of
water withdrawn from nature but that never
reaches an end-user, due to
- Leaky pipes and mains
- Theft
- Meter inaccuracies
Problems with Urban Water Losses
• Surrounding regions experience water stress:
withdrawals outstripping available supplies
• When surplus water is extracted
- Rivers run dry
- Habitats wither
- Wildlife disappears
• More energy required to pump, treat, and
distribute excess water
• This “lost” water, if recovered, could help cities
facing scarcity meet their water needs
Household Water Use,
Selected Cities and Countries
47
Kenya
149
United Kingdom
218
Waterloo, Canada
255
Sydney, Australia
281
Seattle, United States
832
Phoenix, United States
0
200
400
600
800
Liters Per Capita Per Day
Source: Thompson et al. (2001), National Water Demand Management Centre, Environment Agency,
U.K. (2003), Gombos (2003), Water Services Association of Australia (2001), Mayer et al. (1999)
1000
Household Water Use
Tips to reduce indoor household water
consumption by almost 50%:
• Install water-efficient fixtures
(toilets, showerheads, faucets)
• Choose water-efficient appliances
(clothes washers, dishwashers)
Household Water Use
• Large domestic water demand for irrigation of
lawns, landscapes, and golf courses
- 30 billion liters of water a day in the U.S.
• 45 million kg of fertilizers and chemicals used
per year
• Excess fertilizers and chemicals run off into
streams, seep into groundwater
- contaminating drinking water
- polluting lakes and ponds
Household Water Use
To reduce outdoor water consumption…
• Use more efficient sprinklers and irrigation
systems
• Choose natural landscaping and native plants
- drought-adaptive grasses, groundcovers, wildflowers
and plants that thrive naturally in local climate
5. Industrial Water Use and
Material Goods Consumption
• Major water-using industries:
Thermal electric power
Iron and steel
Pulp and paper
Chemicals
Petroleum
Machinery manufacture
• Water is used for cooling, washing,
processing, heating
• In developing countries, pollutant loads
rising along with industrial water demand
Industrial Water Use and
Material Goods Consumption
Incentives for increasing efficiency of
water use in industrial facilities:
• Cost savings
• Need to comply with permit
requirements
• Advances in technologies that allow
process water to be reused and recycled
• Availability of low-cost reclaimed
nonpotable water
How Individuals Can Reduce
Their Impacts on Freshwater
1. Purchase fewer material goods
2. Eat a nutritious, less meatintensive diet
3. Select native plants and grasses
for landscapes, rely on natural
rainfall
How Individuals Can Reduce
Their Impacts on Freshwater
4. Install water-efficient appliances
and fixtures
5. Support local land use ordinances
that protect wetlands, aquifers,
and watersheds
6. Serve on local water management
boards to monitor and enforce
water protection strategies
6. Policy Priorities:
Government Action
1. Protect public trust in water
2. Institute or strengthen
groundwater regulations to
promote sustainable use
3. Implement tiered water pricing
to encourage conservation:
unit price of water increases
along with consumption
Policy Priorities:
Government Action
4. Restrict water use during
seasonal lows
5. Encourage water trading
between willing sellers and
buyers to reallocate available
supply
About the Authors
“Boosting Water Productivity”
by Sandra Postel and Amy Vickers
Sandra Postel is co-author of Rivers for Life:
Managing Water for People and Nature (Island
Press, 2003), and director of the Global Water Policy
Project in Amherst, MA.
More at www.globalwaterpolicy.org
Amy Vickers, author of the award-winning Handbook of
Water Use and Conservation: Homes, Businesses,
Landscapes, Industries, Farms (WaterPlow Press) is
an engineer and water conservation specialist based in
Amherst, MA.
More at www.waterplowpress.com
More information on
State of the World 2004
at www.worldwatch.org