Download Facing the Freshwater CrisisL Some Lessons for Local Officials

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts
no text concepts found
Transcript
Global Water Crisis: How it
could Affect US Cities
Peter Rogers
Harvard University
Keynote Speech
Mayors Water Council—Mayors Water Summit
Breakers Hotel, Palm Beach
November 20, 2008
Outline of Speech
• Magnitude of problem: Society, Economics and Hydrology
– Global and US
• Climate Change: Why focus on water?
–
–
–
–
Demographics or Climate change?
Some forecasts: sea level, precipitation
Floods, droughts, and tropical storms
Remediation and mitigation
• A modest proposal for US cities
– The infrastructure problem
– The quest for ever improved water quality
– Closing the loop on water-wastewater treatment
• Conclusions
Cities and Industries use very little of
total globally available water
Source. Comprehensive Assessment, 2007
Short Term Forecasting
• The scientific community is notoriously bad at short-term
forecasting, never mind long-term forecasting
• We are better at some things like human populations since for
the short-term almost all of the persons likely to procreate in
the next 30 years are already born!
• We are not good at forecasting items derived from population,
but influenced by socio-economic parameters such as
affluence
• For example, in 1937 President Roosevelt convened a panel of
scientists and engineers to assess likely technological advances
in the next 5-10 years. The panel missed all of the major
developments, including radar, jet airplanes, and nuclear
explosions
US WATER WITHDRAWAL FORECAST 1950–2000
1510
1400
1300
1200
1128
Total water withdrawal (bgd)
1000
1510(bgd) NWC (high)
900
888.4
RFF (high)
800
804
NWC (middle)
Billions of gallons per day (bgd)
1100
1000
700
600
563
Sen. Select. Comm. (medium pop.
growth)
WRC (1968)
500
490
400
408
330
300
200
NWC (low)
WRC (1975)
RFF (medium)
100
2000
1995
1990
1985
1980
1975
1970
1965
1960
1955
1950
0
Year
Source. Rogers, 1993, with actual 1995 and 2000 added
What is it now (2008)?
• As far as I can determine the USGS has not yet
cleared for release even the 2005 estimate
• A sad comment on the availability of reliable
data at the national level
• We are left with the 2000 estimate as the basis
of predicting future demands
WHAT ARE THE DIMENSIONS OF THE
WSS PROBLEM IN THE US?
• Most utilities for both water and wastewater have problems
covering the cost of services
• Many have deferred maintenance due to capital shortages
• GAO (2002) estimated that investments between $300 billion and
$1 trillion would be needed over the next 20 years (not include ag.
& ind.)
• These costs apparently did not include the costs of the evolving
storm water regulations estimated, for example, to cost over $23
billion just for the Los Angeles Water Board Region over the next
20 years
• During the past decade, about $7 billion per year has been
provided by federal and state resources
• US Council of Mayors (2008) reports that cities and local
governments spent $64 billion per year from 1992-2005, $82
billion in 2007, and are facing $110 billion per year by 2010
Causes of Global Water Crisis
• Causes of Present Crisis
–
–
–
–
Increasing and urbanizing populations
Increasing wealth
Change in weather patterns
Increasing demand for ever cleaner water
• Causes of Pending Crises
– Continued growth of population and wealth
– Climate induced changes in rainfall, sea level rise,
and frequency of storms and droughts
– Protection of non-human ecosystems
Climate Change has major role in exacerbating the
Pending Global Water Crisis, but it is not the only thing
• Uncertainty of supply
– Intrinsic variability of hydrology with the additional unknown
variability associated with climate change
• Continued rapid economic and population growth
– Increased demands for irrigation water
– Increased demands for urban water
• Restoration of Environmental Flows
– Forced by collapse of aquatic communities, maybe exacerbated by
climate change
• Transboundary water conflicts
– Potential for good or evil, potentially affected by climate change
• Idiosyncrasy of water institutions
– Effective water management is prevented by poor governance, this
needs to be addressed apart from climate change
Water Management and Uncertainty
• The history of water management is one of continuous
adaptation to uncertainties; water engineering is about
learning from mistakes.
• Various rules, procedures, design safety factors have
evolved to accommodate rural and urban users.
• There is a significant turnover in water management
infrastructure: ~ every 30 yrs capacity can be upgraded/
reconfigured to adapt – rehabilitation.
• The discount rate, BCA procedures, maximizing NED
benefits are more relevant than climate uncertainty in
determining modes of adaptation.
Source. Stakhiv, 2007.
What’s Different This Time?
• Since the Medieval warming period (900–1300) we have added 6 billion
people.
• The majority of the earth’s population now is far wealthier than in
previous times.
• By 2050 there will be 9 billion humans seeking resources on the globe.
• Even without global warming, we would need major adaptation strategies
to cope with this huge population increase.
• In the past warm periods the human population was mobile and could
move into more congenial regions; now we have national boundaries.
• By 2007 the majority of the world’s population were urbanized and with
less flexibility to move.
• The next 3 billion will be urban dwellers.
Climate Change
How useful are the predictions to
guide water policy?
Why Focus On Water?
The IPCC (Working Group II, Summary for Policymakers,
2007) identifies 5 key impacts of increasing global average
temperature. These are on: water, ecosystems, food, coasts,
and health.
A closer reading of the texts shows that many of the most
serious impacts on the non-water areas are in fact mediated
via water. So, for instance, impacts on food are largely due
to hydrological changes, aridity has major impacts on the
ecosystems, and health vectors.
The pivotal role of water impacts are largely felt in the socioeconomic sphere, hence its importance to adaptation rather
than mitigation
Which has larger impact:
Demographics or Climate change?
Climate Change Only
Population Change Only
Population and Climate
Change
Red indicates regions where the future water demand is more than 120% of the 2000 demand
Published by AAAS
C. J. Vorosmarty et al., Science 289, 284 -288 (2000)
2025 simulations using 30’ interpolations from CGCM1 and HadCM2
Sea Level Rise
What is realistic to expect over the
next 100 years?
Add or subtract from the 2080 to 2099 ensemble mean (based on 16 AOGCMs) of 0.3 m
James G. Titus and Charlie Richman, Maps of Lands Vulnerable to Sea Level Rise,
EPA, 2001.
IPCC Precipitation Forecasts
18 GCM models give radically different precipitation
estimates for regional rainfall. Impossible to choose
which to use
On the following slides red implies lower than the
year 2000 rainfall and blue implies higher rainfall
For these model results the rain in Florida could
increase, or decrease, by as much as 6 mm per month
in August by 2099 above or below the 5 to 8.5 mm
today
How useful are these forecasts?
NCAR Jan.2030
A2 and B1
Japan & UK
UK Hadley CM3, August 2039 & 2099, B1
Floods, Droughts, and Tropical
Storms
Increased populations at risk, rising wealth, and
increased property values confound time series
analysis.
One thing is clear; for a storm of the same
magnitude the damages increase over time
because of these effects
Fig. 2. (A) Smoothed DAI reconstruction (solid black curve) for the West,
showing two-tailed 95% bootstrap confidence intervals (dashed black curves)
and the long-term mean (thin horizontal black line)
long-term mean
DIA is the number of
exceedences of a specific
PDSI threshold
E. R. Cook et al., Science 306, 1015–1018 (2004)
Published by AAAS
Flood Damages as Percent of GDP
(Based on damages and GDP data in 2000 dollars)
0.5%
25%
0.4%
Mississippi
River Valley
20%
Hurricane
Agnes
Kansas &
Missouri Rivers
0.4%
0.3%
Total damages as percent of GDP
99%
15%
Hurricane
Diane
0.3%
0.2%
61%
Midwest Floods
Teton Dam
Failure
10%
0.2%
0.1%
5%
0.1%
2005
1996
1999
2002
1990
1993
1984
1987
1978
1981
1972
1975
1963
1966
1969
1957
1960
1951
1954
1945
1948
1936
1939
1942
1930
1933
1924
1927
1918
1921
1912
1915
0%
1903
1906
1909
0.0%
Source. Stakhiv, 2007 Katrina (2005) caused $100 billion which was less than 1% GDP
Total flood damages as percent of GDP
138%
1900
Direct flood damages as percent of GDP
0.5%
Direct damages as percent of GDP
Ohio & Lower
Mississippi River
Basins
Mechanisms for
Adapting to Uncertainties
• Planning new investments, or for capacity expansion
(reservoirs, irrigation systems, levees).
• Operation & regulation of existing systems:
accommodating new uses or conditions (e.g. ecology,
climate change, population).
• Maintenance and major rehabilitation of existing systems
(e.g. dam safety, levees, etc.).
• Modifications in processes and demands
(water conservation, pricing, regulation, legal).
• Introduce new efficient technologies (desalting,
biotechnology, drip irrigation, reuse, recycling, solar, etc.).
Source. Stakhiv, 2007
Water Problems in US Cities
Not this…
What’s wrong with this picture?
This is “adequate WSS” according to the WHO!
But this…
Deferred Maintenance?
43% of cities report repair and replacement cycles exceed 50 years for water pipes, and
for sewer pipes 65% have repair and replacement cycles exceeding 200 years
And this…
And Droughts, Sea level rise, and
Tropical storms…
Katrina, 2005
High tide, Miami, 9/27/08, 9:15 am
How serious is the problem of water
and wastewater infrastructure?
• Drinking water and wastewater
declined from a D to a D- in the past
four years
• 43% of cities report repair and
replacement cycles exceed 50 years
for water pipes
• Over a million miles of water pipes in
the U.S. – generally aren’t replaced
until failure
• Some lead – even wood – service
lines and water mains are still in
service today
41
Current Financial Disaster is Crying out for
Government Investment in Infrastructure
• Water and Sewer looks like a good place to invest
• The Cadmus Group (August 2008) estimated that $1
invested in water and sewer infrastructure increases
Gross Domestic Product in the long run by $6.35
(9.7% rate of return).
• One job in water and sewer infrastructure creates 3.68
jobs in the national economy to support that job.
• They claim that these are larger than for highways.
Modest Proposal for US Cities
US Should Close the Loop between
Wastewater and Potable Water
• Increasing demands
– Population
– Affluence
– Droughts
• Ever increasing regulation
– Current EPA 90 contaminants looking towards 129
– Concern about pharmaceuticals in drinking water
• Costs of adding and replacing new treatment plants
– New water and wastewater plants increasingly expensive and subject to
regulatory creep
• Reuse using advanced ultra filtration and RO could solve these problems
– Maintaining a high level of quality at a single plant would reduce the
total cost of two plants neither at high contaminant removal levels
– Would also reduce the demand for “new” water by as much as 40-50%
– The water saved would be “drought-proof” supply.
WATER AND WASTEWATER TECHNOLOGY, Hammer and Hammer, 6th ed.
They said “it would never be
acceptable to consumers”
• The new trend in water-scarce areas in the US and abroad is
to introduce reused (recycled) water into the potable supply
– Orange County’s Groundwater Replenishment System (GWR)
• $480 million, 70 mgd to seawater barrier, future 60 mgd directly to GW
• GWR generates enough water to meet the needs of 500,000 people and
meets all state and federal drinking water standards
– Singapore’s NEWater
• 50 mgd in 2007, planned 500 mgd on line by 2011
– Windhoek, Namibia, probably the first directly to drinking water
• My contention is that given the costs of separate treatment
and the demands for higher levels of contaminant removal,
it will be appropriate for large parts of the water –rich
regions in the US to move in this direction.
The $22.6 trillion global need for all types of water infrastructure from
2005 until 2030 seems like a daunting number, but really how large is it
compared with the global GDP and expenditures in other social sectors?
It turns out to be about 1.5% of annual global GDP, or about $120 per
capita.
Global spending on health amounted to 4.3% of GDP in 2005.
For Africa, with an income of per capita $490, all water infrastructure
would cost $37 per capita per year, and for Asia with an income of $800
per capita the water infrastructure costs would amount to $138 per
capita per year.
These amounts while sounding small to our industrialized country ears
are still very high as a percentage of income, but achievable amounts
for the poor countries and could be reduced with more agricultural
research and sanitation outreach programs.
Six Adaptations necessary to meet increasing population
and affluence with, or without, climate change
•
Increase infrastructure investments
–
•
Asymmetries in water uses
–
•
Coastal cities have almost unlimited supply of potable water; new RO and ultra filtration technologies have
reduced the cost to that of traditional sources (US50 cents per cubic meter)
Eco-sanitation revolution
–
•
Already resolving many water scarce situations; export of agricultural products from water-rich countries
allows water-scarce to economize on domestic water use
Low cost desalination breakthrough
–
•
Irrigation flywheel; 80-85% water used for irrigation, a 10% improvement in efficiency would double the
amounts available for D and I water needs
Virtual water escape hatch
–
•
Huge need for investments in new and improved water supply and wastewater facilities. Even in the
developed world deferred maintenance has left the infrastructure in a dangerous situation.
Decoupling of water and sanitation; dry sanitation is becoming economically feasible even in high density
settings
Water is universally underpriced
–
Large potential for demand side management; except for a few European countries there are huge subsidies to
municipally supplied water—leads to deferred maintenance
Conclusions
• Global crisis; we can have one if we are not
careful
• US crisis: unlikely, we have many options and a
plentiful water supply, but it will be expensive
• There are many mitigation options available
globally and domestically
• We should move to a closed system for urban
water management; it will be easier to manage,
maintain quality, and be drought resistant.
A Bayesian Approach to Dealing
with Global Warming
Despite the variable quality of the
regional evidence, it is prudent to note
that temperatures have risen over the
past century and that we can expect to
experience many of the broad impacts
suggested by the IPCC over the next 50
years. We will live in a world of
increasing hydrological uncertainty
The Romans Ignored The AD 202 GAO Report!
Source: InfoRoma, 2004. www.inforoma.it
DEFERRED MAINTENANCE?