Environmental Encyclopedia
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Environmental Encyclopedia 3
Waste exchange
1,000 times larger than the combined yield of all conven-
tional explosives used during World War II (6.0 Mt), the
Korean War (0.8 Mt), and the Second Indochina War (4.1
Mt). The late-1980s nuclear arsenal was equivalent to 3–4
tons (2.7–3.6 metric tons) of TNT per person on Earth.
Thankfully, the cessation of the Cold War has led to
substantial reductions in the world’s nuclear weaponry,
which has declined from a total explosive yield of about
18,000 Mt in the 1980s to about 8,000 in the mid-1990s.
There were about 64,000 strategic and tactical devices in
1983, but 27,000 in 1993, and planned reductions to 11–
19 thousand in 2003.
Nuclear weapons have twice been used in warfare.
This involved bombs dropped by U.S. forces on Japan, in
an action that brought World War II to an earlier end
than would have occurred otherwise. The first bomb had
an explosive yield equivalent to 0.015 Mt of TNT and was
dropped on Hiroshima on August 6, 1945, and the second
(0.021 Mt) was dropped on Nagasaki a few days later. The
Hiroshima bomb killed about 140,000 people, while the
Nagasaki device killed 74,000. The combined effects of blast
and heat destroyed about two-thirds of the buildings in
Hiroshima, and one-fourth of those in Nagasaki. Although
enormous in comparison with conventional bombs, these
nuclear devices were small in comparison to the typical yield
of modern strategic warheads, which average about 0.6 Mt
and range to 6 Mt.
Not surprisingly, people are concerned about the likely
consequences of a large-scale nuclear exchange. One com-
monly used scenario of a nuclear war is for a limited exchange
of 5,000–6,000 Mt, most of which would be exploded in
the Northern Hemisphere. The predicted effects on people
include the deaths of about 20% of the world’s population,
including as much as 75% of the population of the United
States. The principal cause of death would be thermal radia-
tion, but effects of blast, fire, and
ionizing radiation
would
also be important. Virtually all survivors would be injured
by these same forces. Such an overwhelming loss of human
life, coupled with the physical devastation, would transform
civilization.
It has also been suggested that a nuclear war could
result in a global deterioration of climate, which would cause
additional severe damages. The climatic effects might be
caused by various influences of nuclear explosions, but espe-
cially the injection of large quantities of sooty smoke, inor-
ganic particulates, and gases into the
atmosphere
. These
could interfere with the planet’s
absorption
of
solar energy
and its re-emission of infrared energy. These potential conse-
quences of nuclear warfare have been studied using computer
models of the type that are used to model the effects of
emissions of
carbon dioxide
and
methane
on Earth’s
greenhouse effect
. In general, the predictions are that nu-
1467
clear war could cause a global cooling, or a “nuclear winter,”
which would cause widespread damages to agriculture and
natural ecosystems. The longer-term climatic damages
would add to the enormous destructions that were caused
by blast, thermal radiation, fire, and ionizing radiation within
a short time of the nuclear exchange.
Humans have probably engaged in warfare throughout
their history, and regrettably we appear likely to continue
to do so into the future. Fortunately, the catastrophic effects
of modern technological warfare are being increasingly rec-
ognized, and many nations have been making progress in
avoiding conflicts, particularly amongst the world’s most
heavily armed nations. Because nuclear war has especially
horrific consequences, recent treaties on non-proliferation
of nuclear weapons and nuclear arms reductions provide real
prospects in this regard.
[Bill Freedman Ph.D.]
R
ESOURCES
B
OOKS
Freedman, B. Environmental Ecology. 2nd ed. San Diego: Academic
Press, 1995.
Sivard, R. L. World Military and Social Expenditures, 1996. Washington,
DC: World Priorities, 1996.
Westing, A. H., Explosive Remnants of War. Mitigating the Environmental
Effects. London: Taylor & Francis, 1985.
Westing, A. H., ed. Herbicides in War: The Long-term Ecological Conse-
quences. London: Taylor & Francis, 1984.
P
ERIODICALS
Barnaby, F. “The Environmental Impact of the Gulf War.” Ecologist 21
(1991): 166–172.
Grover, H. D., and M. A. Harwell. “Biological Effects of Nuclear War.
I. Impact on Humans.” Bioscience 35 (1985): 570–575.
Grover, H. D., and M. A. Harwell. “Biological Effects of Nuclear War.
II: Impact on the Biosphere.” Bioscience 35 (1985): 576–583.
Grover, H. D., and G. F. White. “Toward Understanding the Effects of
Nuclear War.” Bioscience 35 (1985): 52–556.
Warner, F. “The Environmental Consequences of the Gulf War.” Environ-
ment 33, no. 5 (1991): 7–26.
Warbler
see
Kirtland’s warbler
Waste exchange
Getting rid of industrial waste poses many problems for those
who generate it. With environmental restraints enforced by
fines, companies must minimize waste at its source, recycle
it within the company, or transport it for off-site
recycling
,
treatment, or disposal.
Environmental Encyclopedia 3
Waste Isolation Pilot Plant
The concept of waste exchange, begun in Canada in
the 1980s, involves moving one institution’s overstock, obso-
lete, damaged, contaminated, or post-dated materials to an-
other site that might be able to use it. Waste exchange
companies sprang up to meet this need, but the need for
effective and rapid communication between these companies
soon became apparent, because much of the waste involved
in the program had to be dealt with on a timely basis.
Hazardous wastes, for example, must be disposed of within
90 days.
In 1991, the
Environmental Protection Agency
(EPA) gave a $350,000 grant to the Pacific Materials Ex-
change in Spokane, Washington, to develop a free computer
online network. Servicing about 30 waste exchange compa-
nies in the United States and Canada, the National Materials
Exchange Network acts like “an industrial dating service,”
according to director Robert Smee. The service is easily
accessible by an 800 number [800-858-6625] to anyone with
a computer and a modem. Smee estimates that the computer
network in its first year of operation saved companies $27
million in disposal fees.
While protecting the identity of companies generating
waste, the network publishes a want list and an available
source list of laboratory
chemicals
, paints, acids, and other
wastes. Some are hazardous, but others are innocuous, such
as one company’s scrap wood, which was bought by another
to be ground up for air freshener. See also Industrial waste
treatment; Solid waste; Waste management
[Stephanie Ocko]
R
ESOURCES
P
ERIODICALS
Manning, S. “Waste Exchanges: Why Dump When You Can Deal?” PEM:
Plant Engineering & Maintenance (June 1990): 32–41.
Schwartz, E. I. “A Data Base That Truly Is ‘Garbage In, Garbage Out’.”
Business Week (September 17, 1990): 92.
Waste Isolation Pilot Plant
Developing a safe and reliable method for disposing of radio-
active wastes is one of the chief obstacles to broader applica-
tions of
nuclear power
. Nearly a half century after the
world’s first nuclear reactor was opened, the United States
still had no permanent method for the isolation and storage
of wastes that may remain dangerously radioactive for thou-
sands of years. Scientific disputes, technical problems, and
political controversies have slowed the pace at which waste
disposal systems can be studied and built. The history of the
Waste Isolation Pilot Plant (WIPP), located near Carlsbad,
New Mexico, is an example of how difficult the solution to
this challenge can be.
1468
WIPP was designed by the
U.S. Department of En-
ergy
(DOE) in the 1970s to test methods for isolating and
storing low- and intermediate-level and transuranic radioac-
tive wastes. (Transuranic wastes are produced mainly by
nuclear weapons
plants and consist of clothing, debris,
tools, and other disposable items that have been contami-
nated with radioactive wastes.) Researchers decided that the
most promising disposal system was to seal the wastes in
steel containers and bury these in deep caves built into natural
salt beds. They knew that salt beds could absorb the heat
produced by
radioactive waste
, and that the beds were
usually located in earthquake-free zones. In addition, salt
bed caves were attractive because scientists believed they
were dry, which prevented wastes from
leaching
out of their
tanks. Salt would also tend to creep into openings, thus
sealing the drums for thousands of years.
Between the 1970s and 1990s, the DOE spent more
than $1 billion building huge caves 2,100 ft (640 m) under-
ground near Carlsbad. The plan was to bury 800,000 drums
of nuclear waste and study its behavior over a number of
years. It was soon discovered, however, that some salt beds
contain layers of brine (salt water), indicating that such beds
are not always dry. Salt in the caves has begun to “creep,”
or slowly move, as expected. Concern about the possible
damages caused by the storage of radioactive materials be-
came so intense that today the WIPP is regulated as carefully
as a nuclear power plant, providing regular reports to 28
different governmental agencies.
Controversy created a standstill at WIPP and pre-
vented waste drums from being buried there for over two
decades. In 1991 Secretary of Energy James Watkins an-
nounced that the DOE could wait no longer, and wastes
that had been stored at 10 sites around the nation for 20
years awaiting disposal were to be shipped to WIPP. Envi-
ronmentalists and some government officials in New Mexico
reacted strongly to the announcement. They pointed out
that Congress was required to give specific approval before
any wastes could actually be buried at WIPP. A federal
judge ruled that Watkins could not carry out his plan until
Congress acted, and the experimental tests at WIPP were
once again put on hold.
In the late 1990s, after much deliberation and further
testing, Congress approved WIPP for nuclear waste storage.
The facility received its first shipment of waste on March
26, 1999. Under congressional mandate, WIPP will only
receive transuranic waste and no commercial or high-level
nuclear waste. In 2000, more than 99% of existing U.S.
transuranic waste was being temporarily stored in drums
on nuclear defense sites at 23 locations, including ones in
California, Colorado, Idaho, Illinois, Nevada, New Mexico,
Ohio, Tennessee, South Carolina, and Washington. At first,
the DOE authorized WIPP to only receive waste from Los
Environmental Encyclopedia 3
Waste management
Alamos National Laboratory in New Mexico, from the Idaho
National Engineering and Environmental Laboratory, and
from Rocky Flats, a former nuclear weapons plant near Den-
ver, Colorado. By 2002 the facility had begun receiving waste
from other areas, including South Carolina’s
Savannah
River Site
.
On April 6, 2002, WIPP received its first shipment
of waste under the Central Characterization Project (CCP)
from the Savannah River Site. CCP is a program designed
to make the cleanup of transuranic wastes more efficient,
safe, and cost-effective. Characterization involves using a
mobile
loading
system to check and approve drums of waste
before loading them into specialized shipping containers for
transfer to WIPP.
WIPP is projected to house up to 46.7 million gal
(177 million l) of transuranic waste, which will remain radio-
active for more than 10,000 years. By 2008, the number of
shipments is estimated to grow to nearly 1,400 per year,
declining again as the facility fills up. By 2035 the facility
is projected to have received almost 37,000 truckloads of
nuclear waste, barring operational or legal changes. Ship-
ments are moved only in good weather and at night, when
traffic is lighter to avoid accidents, and routed around major
cities. Shipments are tracked by satellite for safety.
At the beginning of the twenty-first century, about
61 million Americans lived within 50 mi (80 km) of a military
nuclear waste storage site. By the time WIPP has been in
operation for 10 years, that number is projected to drop to
four million. By May 2002, a total of 814 shipments had
been sent to the storage facility, totaling 23,852 containers.
[David E. Newton and Douglas Dupler]
R
ESOURCES
B
OOKS
Gerrard, Michael B. Fairness in Toxic and Nuclear Waste Siting. Cambridge,
MA: MIT Press, 1994.
Rahm, Dianne, ed. Toxic Waste and Environmental Policy in the Twenty-
first Century United States. Jefferson, NC: McFarland & Co., 2002.
Shrader-Frechette, K. S. Burying Uncertainty: Risk and the Case Against
Geological Disposal of Nuclear Waste. Berkeley: University of California
Press, 1994.
Streissguth, Thomas, ed. Nuclear and Toxic Waste. San Diego, CA:
Greenhaven Press, 2001.
O
THER
“WIPP Receives Waste Characterized With Mobile System.” DOE News
April 12, 2002 [cited July 6, 2002]. <http://www.wipp.carlsbad.nm.us/pr/
2002/WIPPReceivesCCPMobile.pdf>.
O
RGANIZATIONS
Department of Energy, Carlsbad Field Office, PO Box 3090, Carlsbad,
NM 88221, (505) 234-7352, <http://www.wipp.carlsbad.nm.us>
1469
Waste management
The way that we manage our waste materials is a sign of
the times. In our agrarian past, throwing
garbage
out into
the street for roving pigs to eat seemed like a perfectly
reasonable method of waste management, since most of what
we threw away was organic material that increased the bulk
of the pig and eliminated residuals we did not want. As
manufacturing became a larger part of industry and materials
had potential for
recycling
we saw the advent of the another
kind of
scavenger
, the “junk man,” who pulled from the
waste stream
those materials that had value. This practice
increased during the Great Depression and even more so
during World War II. During the war there were shortages
of metals and cloth as many raw materials were diverted
from domestic use to war needs. People got into the habit
of
conservation
. Things were not thrown away unless they
had no further use either as is or in a remanufactured state.
The situation has changed in modern times.
As Jim Hightower points out in the foreword to War
on Waste (1989), “Every year we toss into city dumps 50
million tons of paper, 41 million tons of food and
yard
waste
, 13 million tons of metals, 12 million tons of glass,
and 10 million tons of plastic.” In addition, he points out
that the
Environmental Defense
Fund has calculated that,
as a nation, we throw away enough iron and steel to supply
domestic auto-makers continuously; enough glass to fill the
twin towers of New York City’s World Trade Center every
two weeks; enough
aluminum
to rebuild our commercial
air fleet every three months; and enough office and writing
paper to build a 12-ft (3.7 m) Great Wall coast to coast
every year. The examples go on and on. The opportunity
to manage this tremendous resource through careful waste
management practices is urgent. Waste is indeed a renewable
resource. This renewable resource, if managed well, could
provide us with the ability to reserve our natural non-renew-
able resources until we really need them.
Most states and major metropolitan areas have a hier-
archy of waste management options that guide state and
local planning. Although there are refinements of this list
in some areas, the standard hierarchy, in order of preference,
is: reduce,
reuse
, recycle, compost, waste-to-energy (
incin-
eration
), and
landfill
. Looking at each of these options
individually gives a better understanding of an integrated
waste management system.
Managing waste through a process of reduction is
almost always the first line of defense and viewed as most
desirable by waste management professionals. Reduction is
an attempt not to generate waste in the first place. This
means making certain consumer decisions that eliminate the
potential for waste generation. Buying produce in bulk so
that packaging is kept at a minimum is one simple consumer
Environmental Encyclopedia 3
Waste management
Schematic representation of the Waste Isolation Pilot Plan. (U. S. Department of Energy.)
decision that can have a profound effect, since over 40% of
the waste stream is packaging material. To further reduce
waste, consumers can bypass disposable items, such as dis-
posable razors and cameras, and have small appliances re-
paired rather than buy new ones. Using cloth dishtowels
and diapers eliminates paper towels and
disposable diapers
from the waste stream.
Reuse is often the second line of defense. This is
the small area between avoiding waste and recycling post-
consumer materials. A creative way to support reuse of mate-
rials is to make them available to those who can use them.
Some cities have put in place a center where containers and
various post-consumer materials that have been cleaned and
source-separated are available to elementary school teachers
for art projects. Another example of reuse is consignment
shops. These stores will take clothing and small household
items on consignment from people and then sell them and
divide the profit with the owner.
Recycling is on the increase. Goals of recycling 15%,
25%, and even 50% of waste material have been called for
in cities all across the United States. Many believe recycling
is a major waste management solution. Industries in the
1470
United States are able to recycle quite a variety of materials.
Paper, glass, metals,
plastics
, yard and
food waste
, motor
oil, batteries, tires, asphalt, car bumpers, and all manner of
scrap metal can be recycled. There is truly little that cannot
be recycled, but in some cases, industry is not ready. Manu-
facturing equipment has not yet been retrofitted to accom-
modate the heterogenous nature of the waste stream. Also,
communities are a dispersed source of “raw” material for
manufacturers, and the cost of gathering sufficient tonnage
of glass, tin, or other “raw” material for manufacturing is
prohibitive. Probably the single most restrictive obstacle to
full scale recycling is human behavior. As we look at recycling
as a closed-loop waste management process we realize that
we must source-separate and clean post-consumer waste ma-
terials, then we must get them to the point where they can
be used and made into a new product. To close the loop,
someone must buy that product. All of these activities de-
mand a behavioral change on the part of consumers and
manufacturers.
Composting
is the biological breakdown of organic
matter under
aerobic
conditions. Composting is seen as a
major waste management option for large and small commu-
Environmental Encyclopedia 3
Waste reduction
nities. The most common form of composting is the layering
of leaves, grass and twigs and sometimes kitchen waste in
a backyard compost bin. This very simple technology can
also be done at the municipal level, as a community picks
up leaves and other yard waste at the curb and trucks it to
a central location where it is composted in long tent-shaped
piles of refuse called windrows, or inside buildings where
mechanical systems speed the compost process. Like recycl-
ing, composting requires a behavioral change on the part of
homeowners. People must prepare the material and get it
to the curb on the appropriate day. Some drawbacks to
composting are that the process can generate unpleasant
odors if the compost pile is not managed well. This means
turning the pile frequently and maintaining aerobic condi-
tions so that
decomposition
proceeds rapidly.
Incineration is not really a new waste management
option. Incineration of
solid waste
was practiced in the
early 1900s. However, not until the early 1970s did we began
to look seriously at
solid waste incineration
with
energy
recovery
as a major goal. There really are two types of
waste-to-energy systems. One is a
mass burn
technology
which does very little to the waste stream before it reaches
the furnace. The other system is a refuse-derived fuel (RDF)
in which waste is shredded before being delivered to the
furnaces. Drawbacks to this system are ash disposal and
control of air emissions. Concerns over dioxins in
stack
emissions
has caused many supporters to think twice about
waste-to-energy. In addition, the issue of where to dispose
of the sometimes toxic ash residue must be dealt with.
Landfills are still the most common waste manage-
ment option. Between 75% and 85% of the nation’s waste
still goes to landfills. Three types of landfills are constructed
for different types of waste materials.
Type III landfills are the least expensive to build and
can accommodate construction debris and other inert mate-
rial. Most common are sanitary Type II landfills. These are
constructed according to the criteria in subtitle D of the
Resource Conservation and Recovery Act
(RCRA).
Newer
municipal solid waste
landfills are usually equipped
with synthetic liners, leachate collection systems, monitoring
wells
and in some cases
methane
wells to draw off the gas
that collects in landfills. Type II landfills will take any waste
except
hazardous waste
. Hazardous waste can only be
disposed of in a Type I landfill. These landfills are con-
structed in a more rigorous manner and are used primarily
for contained
chemicals
and such waste as
asbestos
.
The biggest challenge surrounding modern landfills is
the issue of siting.
Not in my backyard
(NIMBY) is a
well-known syndrome. Current landfill construction has
slowed and many of the old landfills have closed or are slated
for closure. There are currently about 3,000 Type II landfills
in the continental United States. As more landfills close,
1471
the life span of those remaining is shortened. Large multina-
tional companies in the waste management business are
attempting to site large regional landfills. In some cases, large
companies are offering very attractive incentive packages to
communities that are willing to site a landfill within their
jurisdictions. Whatever method of disposal is used, the pro-
cess of managing waste must bring into play a cooperative
effort between manufacturers, merchants, citizens, and waste
management experts if it is to be successful. See also Renew-
able resources; Source separation
[Cynthia Fridgen]
R
ESOURCES
B
OOKS
Blumberg, L., and R. Gottlieb. War on Waste. Covelo, CA: Island
Press, 1989.
Kharbanda, O. P., and E. A. Stallworthy. Waste Management: Toward a
Sustainable Society. Westport, CT: Auburn House/Greenwood, 1990.
Underwood, J. D., et al. Garbage: Practices, Problems, and Remedies. New
York: INFORM, 1988.
Waste reduction
Waste reduction aims to reduce environmental
pollution
by minimizing the generation of waste. It is also often an
economically viable option because it requires an efficient
use of raw materials. Waste-reduction methods include
modifying industrial processes to reduce the amount of waste
residue, changing raw materials, or
recycling
or reusing
waste sources.
It is more difficult to alter existing industrial processes
than it is to incorporate waste-reduction technologies into
new operations. Large-scale changes in production equip-
ment are essential to achieving waste reduction. Proper han-
dling of materials and
fugitive emissions
reduction, as well
as plugging leaks and preventing spills, all help in waste
reduction. Process equipment must be checked on a regular
basis for corrosion, vibrations, and leaks. Increases in auto-
mation and the prevention of vapor losses also help reduce
waste generation.
Changes in what an industry puts into a process can
be used to reduce the amount of waste generated. One
example is the substitution of raw materials such as water
to clean a part instead of solvents. End-products can also
be modified to help reduce waste. Another aspect of waste
reduction is the control of fugitive emissions by placing
a floating roof on open tanks, for example. Other waste-
reduction options include the installation of condensers, au-
tomatic tank covers, and increasing tank heights. But these
and other decisions on waste reduction very much depend
on the size and structure of a company. See also Industrial
Environmental Encyclopedia 3
Waste stream
waste treatment; Recyclables; Reuse; Toxic use reduction
legislation; Waste management; Waste stream
[James W. Patterson]
R
ESOURCES
B
OOKS
Robinson, W. D., ed. The Solid Waste Handbook. New York: Wiley, 1986.
Underwood, J. D., et al. Garbage: Practices, Problems, and Remedies. New
York: INFORM, 1988.
O
THER
Waste Minimization: Environmental Quality With Economic Benefits. Wash-
ington, DC: U.S. Environmental Protection Agency, Office of Solid Waste
and Emergency Response, 1987.
Waste stream
Streams of gas, liquid, or solids that are the by-products of
a treatment operation or industrial process. The term has
also been used to describe the flow of
solid waste
from
various sources, including individual homes. The term is
often used in
pollution
prevention strategies and
industrial
waste treatment
initiatives. Many industries are now re-
quired to pretreat their wastes and seek ways to minimize
waste production.
Wastewater
Water used and discharged from homes, commercial estab-
lishments, industries,
pollution control
devices, and farms.
The term wastewater is now more commonly used than
sewage, although for the most part, the terms are synony-
mous. Domestic or sanitary wastewater refers to waters used
during the course of residential life or those discharged from
restrooms. Industrial wastewaters refer to those generated
by an industry. Municipal wastewaters are waters used by a
municipality, so they would likely include both sanitary and
industrial wastewaters. Combined wastewater refers to a
mixture of sanitary or municipal wastewaters and stormwa-
ters created by rainfall.
Wastewater treatment
see
Sewage treatment
Water allocation
Agriculture and fishing have different needs for water, as
do manufacturing industries, cities, and
wildlife
. Water allo-
cation is the process of distributing water supplies to meet
the various requirements of a community.
1472
Determining how to allocate water supplies requires
the consideration of certain factors, including the source of
the water and methods for obtaining it. The cost of the
water supply and
water treatment
systems are also taken
into account, and the intended uses are reviewed. Water use
is classified by whether it is an instream or a withdrawal use
and by whether it is a consumptive or nonconsumptive use.
Instream uses include navigation, hydroelectric power, and
fish and wildlife habitats, while withdrawal uses remove
water from the source. Consumptive uses make the water
unavailable, either through evaporation or
transpiration
,
or through incorporation into products or saltwater bodies.
Water withdrawn but not consumed can be treated and
returned to the water supply for
reuse
downstream.
The demand for water is determined by combining
the sum of the amount of water required for instream needs
with the sum of the amount of water needed for withdrawal
uses. This sum is compared to the amount in the water
supply. If it is equal to or greater than the sum, then the
supply will meet the demand, but if this is not the case,
measures to reduce consumption or increase the water supply
need to taken.
About 70% of water supplies worldwide go to food
production. Industry uses 23% and cities use about 7% of
water supplies. In the western United States, for example,
about 85% of the water supplies are currently used by farming
operations at government-subsidized rates. Cities and indus-
try as well as populations of fish and wildlife split the re-
maining 15%. Some politicians and environmentalists con-
sider this division unfair, and assert that water allocation
should be controlled by environmental awareness. They sug-
gest seeking new ways of getting more water to more people
while protecting wildlife and
wetlands
.
Government agencies own most of the water supplies
in the western United States, and they own about 65% of
the supplies in the east. Those who control the water supplies
govern its use, though regulations on ownership vary by
state. In western states, supplies are on a first-owned, first-
served basis, even if others later run short. The distribution
of supplies and shortages is shared more equally in the east.
Some water allocation programs look toward
conser-
vation
to meet water needs. Certain ordinances, in Califor-
nia for example, restrict and limit water usage. One method
of enforcing compliance that has been used there is publish-
ing the names of people who do not abide by the ordinances
to embarrass them. Another method uses a special section
of the police force for checking water use. These officers give
first-time offenders information on
water conservation
.
They fine repeat offenders.
Wells
,
dams
, reservoirs, conveyance systems, and arti-
ficial ponds physically control water supplies. Wells draw
out
groundwater
. The other constructions manage surface
Environmental Encyclopedia 3
Water conservation
water. Some areas use
desalinization
techniques to get fresh
water from seawater.
A well taps groundwater through a hole sunk to an
aquifer
. An aquifer is a
permeable
layer of rock containing
water trapped by layers of impermeable rock. If the pressure
is sufficient, the water will come to the surface under its
force, a type of well known as an
artesian well
.Ifthe
pressure is not sufficient for an artesian well, a pump is used
to mechanically drag the water to the surface.
Dams are constructed to halt some or all of a river’s
flow. The region behind the dams, where water collects, is
called an impounding, or water collecting,
reservoir
. Each
dam is designed for a specific use, though dam types may
be combined depending on the river and the community’s
needs. Storage dams hold water during times of surplus for
periods of deficit, such as holding the spring
runoff
for the
summer dry season. Along with providing a water supply,
storage dams can improve (or harm) habitats for fish and
wildlife, create electricity, and help in
irrigation
and flood
control. Diversion dams affect the course of a river, pre-
venting it from flowing forward so that a conveyance system
can redirect it to irrigate fields or to fill a distant storage
reservoir. These are often used in the western United States,
resulting in damage to downstream areas. Lack of water can
destroy fisheries and wildfowl habitats, and shorelines and
deltas erode when no
sediment
comes downstream to re-
place what the ocean washes away. Detention dams control
floods and trap sediment. Floods are controlled to prevent
destruction of communities and habitats downstream from
the dam. Trapping sediment causes the downstream portion
of the river to be cleaner.
Conveyance systems divert streams so they flow where
humans most need them. Conveyance systems include
ditches, canals, and aqueducts (also known as transmission
stations). Artificial ponds store water that is pumped in using
a conveyance system. Aqueducts consist of closed conduits
or pipes. A closed system helps to prevent contamination.
A pump system helps the flow when the water level is not
high enough for gravity to take over. Consumer demand for
water varies by day and by season, and enclosed ground
reservoirs and water towers may be used to store treated
water and meet peak demands.
Only about 3% of the earth’s water is fresh, and of
that, 23% is available for use as surface water and ground-
water. The rest is in the unusable form of glacial ice. The
amount of freshwater is not increasing with the global popu-
lation, and about a third of the people in the world now
live in countries with water problems. These facts make the
equitable allocation of water more difficult, and the need
for wise water management more acute. Worldwide short-
ages also make it important for water management to control
the quality of water. Farming runoff, urbanization, and in-
1473
dustry all reduce
water quality
, which causes health and
environmental problems, including algal blooms caused by
nitrogen-rich fertilizers, and
acid rain
. One survey done by
the
Environmental Protection Agency
(EPA) found that
over half of the rivers, lakes, and streams in use in the United
States have been nearly or totally destroyed by
pollution
.
Pollutants have also made it difficult and expensive to recover
and purify groundwater. Purification treatments in general
can be expensive or difficult to obtain, and this causes poor
water quality in many parts of the world.
Competing needs have also created severe problems;
including lowered water pressure, decreased stream flow,
land
subsidence
and increased
salinity
. Additionally,
over-
grazing
,
deforestation
, loss of water-retaining
topsoil
,
and
strip mining
decrease the amount of available water.
Treating sewage before returning it to the water supply
and properly disposing of
chemicals
can improve water
quality and increase the amount of usable water available.
Reducing consumption can prevent water shortages. House-
holds and industries can lower their water consumption by
employing devices that decrease the amount of water used
in, for example, showers,
toilets
, and dishwashers. Farmers
can lower their water consumption by growing drought-
resistant crops instead of ones requiring large quantities of
water, such as alfalfa, and by using more efficient watering
techniques. These methods not only stabilize water supplies,
they also reduce the cost to the consumer. Another method
for use in water shortages is desalinization of sea water.
Desalinization plants remove the salt from sea water and
purify it. Although such plants can be expensive, the expense
can prove to be less than attempting to pipe fresh water in
from sources already strained. See also Aquifer restoration;
Drinking-water supply; Groundwater pollution; Safe Drink-
ing Water Act; Water quality standards
[Nikola Vrtis]
R
ESOURCES
P
ERIODICALS
“California Drought Cops.” Newsweek (April 30, 1990): 27.
Davis. P. A. “Senate Energy Keeps Spigot on for California Agribusiness.”
Congressional Quarterly Weekly Report (March 21, 1992): 723.
Kent, M. M. “New Report Studies Population, Water Supply.” Population
Today (December 1992): 4–5.
O’Reilly, B. “Water: How Much Is There and Whose Is It?” Fortune
(March 25, 1991): 12.
“The U.S. No Water to Waste.” Time (20 August 1990): 61.
Water conservation
Seventy-one percent of the earth’s surface is covered by
water—an area called the hydrosphere, which makes up all
Environmental Encyclopedia 3
Water conservation
of the oceans and seas of the world. Only 3% of the earth’s
entire water is freshwater. This includes Arctic and Antarctic
ice,
groundwater
, and all the rivers and freshwater lakes.
The amount of usable freshwater is only about 0.003% of
the total. To put this small percentage in perspective, if the
total water supply is equal to one gallon, the volume of the
usable freshwater supply would be less than one drop. This
relatively small amount of freshwater is recycled and purified
by the
hydrologic cycle
, which includes evaporation, con-
densation, precipitation,
runoff
, and
percolation
. Since
most of life on earth depends on the availability of freshwater,
one can say “water is life.”
Worldwide, agricultural
irrigation
uses about 80% of
all freshwater. Cooling water for electrical
power plants
,
domestic consumption, and other industry use the remaining
20%. This figure varies widely from place to place. For
example, China uses 87% of its available water for agricul-
ture. The United States uses 40% for agriculture, 40% for
electrical cooling, 10% for domestic consumption, and 10%
for industrial use.
Water
conservation
may be accomplished by improv-
ing crop water utilization efficiency and by decreasing the
use of high-water-demanding crops and industrial products.
The table shows the amount of water, in pounds, required
to produce one pound of selected crops and industrial prod-
ucts (one gal = 7.8 lb).
Freshwater sources are either surface water (rivers and
lakes) or groundwater. Water that flows on the surface of
the land is called surface runoff. The relationship between
surface runoff, precipitation, evaporation, and percolation is
shown in the following equation: Surface runoff = precipita-
tion - (evaporation + percolation): When surface runoff re-
sulting from rainfall or snowmelt is confined to a well-
defined channel it is called a river or stream runoff
Groundwater is surface water that has permeated
through the
soil
particles and is trapped among porous soils
and rock particles such as sandstone or shale. The upper
zone of saturation
, where all pores are filled with water,
is the
water table
. It is estimated that the groundwater is
equal to 40 times the volume of all earth’s freshwater includ-
ing all the rivers and freshwater lakes of the world.
The movement of groundwater depends on the poros-
ity of the material that holds the water. Most groundwater is
held within sedimentary aquifers. Aquifers are underground
layers of rock and soil that hold and produce an appreciable
amount of water and can be pumped economically.
Water utilization efficiency is measured by water with-
drawal and water consumption. Water withdrawal is water
that is pumped from rivers, reservoirs, or groundwater
wells
,
and is transported elsewhere for use. Water consumption is
water that is withdrawn and returned to its source due to
evaporation or
transpiration
.
1474
Water consumption varies greatly throughout the
world. A conservative figure for municipal use in the United
States is around 150 gal (568 L) per person per day. This
includes home use for bathing, waste disposal, and landscape
in addition to commercial and industrial use. The total water
demand per person is around 4,500 gal (17,000 L) per person
per day when one accounts for the production of food, fiber,
and fuel. The consumptive use world wide is considerably
less than that for the United States.
According to the United Nations World Health Orga-
nization (WHO), 5 gal (18 L) per person per day is consid-
ered a minimum water requirement. The majority of the
people in the undeveloped world are unable to obtain the
five gallon per day minimum requirement. The WHO esti-
mates that nearly two billion people in the world risk con-
suming contaminated water. Waterborne diseases such as
polio, typhoid, dysentery, and
cholera
kill nearly 25 million
people per year. In order to meet this demand for freshwater,
conservation is an obvious necessity.
Since irrigation consumes 80% of the world’s usable
water, improvements in agricultural use is the logical first
step in water conservation. This can be accomplished by
lining water delivery systems with concrete or other impervi-
ous materials to minimize deep percolation or by using
drip
irrigation
systems to minimize evaporation losses. Drip irri-
gation systems have been successfully used on fruit trees,
shrubs, and landscape plants.
Subsurface irrigation is an emerging technology with
extremely high water utilization efficiency. Subsurface irriga-
tion uses a special drip irrigation tubing that is buried 6–8 in
(15–20 cm) underground with 12–24 in (26–50 cm) between
lines. The tubing contains emitters, or drip outlets, that
deliver water and dissolved nutrients at the plant’s root zone
at a desired rate. In addition to water conservation, subsur-
face irrigation has several advantages that overhead sprinklers
do not: no overwatering, no disease or
aeration
problems,
no runoff or
erosion
, no weeds, and no vandalism. Subsur-
face irrigation in California has been used on trees, field
crops, and lawns with up to 50% water savings.
Xeriscape, the use of low water consuming plants, is
a most suitable landscape to conserve water, especially in
dry, hot urban regions such as the Southwestern United
States, where approximately 50% of the domestic water con-
sumption is used by lawns and non-drought tolerant land-
scape. Plants such as cacti and succulents, ceanothus, arctos-
taphylos, which is related to foothill manzanita, trailing
rosemary (Rosemarinus officinale), and white rock rose (Cistus
cobariensis) adapt well to hot, dry climates and help conserve
water.
In addition to improving irrigation techniques, water
conservation can be accomplished by improving domestic
use of water. Such a conservation practice is the installation
Environmental Encyclopedia 3
Water diversion projects
of the ultra-low-flush (ULF)
toilets
in homes and commer-
cial buildings. A standard toilet uses 5–7 gal (19–26 L) of
water per flush, while the ultra-low-flush toilet uses 1.5 gal
(5.7 L). Research in Santa Monica, California, shows that
replacing a standard toilet with an ULF saves 30–40 gal
(114–151 L) of water per day, which is equivalent to 10,000–
16,000 gal (37,850–60,500 L) per year.
Another way to conserve the freshwater supply is to
extract freshwater from sea water by
desalinization
. Desali-
nization, the removal of soluble salts and other impurities
from seawater by distillation or reverse osmosis (RO), is
becoming an increasingly acceptable method to provide high
quality pure water for drinking, cooking, and other home
uses. It is estimated that the 1993 world production of desali-
nated water is about 3.5 billion gal (13 billion L) per day.
Most desalinated water is produced in Saudi Arabia, Persian
Gulf Nations, and, more recently, in California. The cost
of desalinated water depends upon the cost of energy. In
the United States, it is about three dollars per thousand
gallons, which is four to five times the cost paid by urban
consumers and over 100 times the cost paid by farmers for
irrigation water. The idea of using desalinated water for
irrigation is, currently, cost prohibitive.
Water has played a vital role in the rise and fall of
human cultures throughout history. The availability of usable
water has always been a limiting factor for a region’s ecologi-
cal
carrying capacity
. It is important that humans learn to
live within the limit of available
natural resources
. Conser-
vation of water alone will not extend the natural carrying
capacity for an indefinite period of time. Since the supply
of available and usable water is finite, the consumption per
person must be reduced. A permanent solution to the water
shortage problem can be accomplished by living within the
ecosystem
carrying capacity or by reducing the number of
consumers through effective control of
population growth
.
[Muthena Naseri]
R
ESOURCES
B
OOKS
Buzzelli, B. How to Get Water Smart: Products and Practices for Saving Water
in the Nineties. Santa Barbara: Terra Firma Publishing, 1991.
Clarke, R. Water: The International Crisis. Cambridge: MIT Press, 1993.
Yudelman. M., et al. New Vegetative Approaches to Soil and Water Conserva-
tion. Washington, DC: World Wildlife Fund, 1990.
P
ERIODICALS
Postel, S. “Plug the Leak, Save the City.” International Wildlife 23 (January-
February 1993): 38–41.
1475
Crop Pounds of Water
1 lb. cotton 16,000
1 lb. beef 6,400
1 lb. rice 4,400
1 lb. loaf of bread 1,200
Industrial product Pounds of Water
1 automobile 800,000
1 lb. aluminum 8,000
1 lb. paper 800
1 gallon gasoline 80
Water cycle
see
Hydrologic cycle
Water diversion projects
Water diversion projects include the construction of
dams
,
levees, pumping stations,
irrigation
canals, or any other
manmade structure that modifies the natural flow of a water-
way. Diversion projects may be developed for purposes of
hydroelectric power generation, farm irrigation, consumer
and industrial water supply, and flood control. Throughout
human history, communities have altered river systems for
their own advantage. There is evidence that large-scale proj-
ects dating over 2000 years ago existed in China, the Medi-
terranean, and the Middle East.
Water diversion globally
In the early twenty-first century, water is one of the
commodities deemed most important to the well-being of
nations. As of 2002, the world population of 5.6 billion is
growing at an annual rate of approximately 90 million, and
the global demand for water is expected to rise by 2–3%
annually in the decades to come.
Globally, of the more than 45,000 large dams ([49.2
ft; 15 m] or more in height, according to the International
Commission of Large Dams), China has the greatest number
with approximately 24,671 large dams, followed by the
United States and India with 6,575 and 4,291 respectively.
Approximately two-thirds of world’s existing large dams are
located in developing countries.
Although clean freshwater is a valuable commodity
and is short supply in many regions of the world, issues
surrounding its diversion and use are often the subject of
heated debate. One large-scale dam project that has been
hotly debated is the Mekong River project in Southeast Asia.
Nations of the region want to control and develop the river
Environmental Encyclopedia 3
Water diversion projects
basin; environmentalists want to protect it; and caught in
the middle is the river itself and the millions who depend
on it for their livelihood.
The fields and numerous tributaries that feed into the
Mekong River are home to more than 50 million people.
Although most of the Mekong basin remains undeveloped,
more than 200 dams have been proposed for the Mekong
and its many tributaries. In addition to irrigating rice fields
in
arid
regions, the diverted water for the first time offers
the opportunity for local inhabitants to produce a variety of
crops, thereby fueling economic growth and development.
Yet tens of thousands of families will be forcibly relo-
cated; fisheries will collapse as upstream access to millions
of fish is blocked; farmland will be flooded; and development
will further restrict the river, leading to potential worsening
of floods. Like other major water diversion projects around
the world, the Mekong project illustrates some of the pro-
found social, economic, and environmental effects of dam-
ming and redirecting the world’s rivers.
Water diversion in the United States
Most large-scale water diversion projects in the United
States are located along river systems in the western half of
the country, where the dry, arid terrain is dependent on
water diversion from high capacity rivers—like the Colorado,
Columbia, Missouri, and Snake—for municipal and irriga-
tion water supplies. The Hoover Dam, Grand Coulee Dam,
Columbia River Basin Project, and scores of other dams
and diversion projects are built and maintained by the U.S.
Bureau of Reclamation
(USBR), which was established by
the Department of the Interior under the National
Reclama-
tion
Act of 1902.
Water diversion practices and management in the
Western states developed by necessity. Low precipitation
levels in the western states meant that pioneer farmers had
to find alternate methods of irrigating their crops. The
USBR was so named because it was charged with the task
of “reclaiming” the dry
desert
landscape for farming and
homesteading through irrigation.
The Bureau’s first major diversion project, the Hoover
Dam and adjacent
reservoir
Lake Mead, was authorized
in 1928 and completed in 1936. In addition to providing
water for agriculture, community, and industrial use, the
dam also generates 4 billion kilowatt-hours of hydroelectric
power annually for California, Arizona, and Nevada.
As of May 2002, USBR managed 348 reservoirs that
hold a capacity of 245 million acre-ft (302.2 billion m
3
)of
water. The Bureau is the largest wholesale water supplier in
the United States, supplying irrigation water for 10 million
acres of farmland and 31 million people across the West.
In addition, USBR generates over 42 billion kilowatt hours
of hydroelectric power annually from its 58
power plants
.
1476
Along with the U.S.
Army Corps of Engineers
, the Bureau
is responsible for the majority of national water projects.
Environmental impact
Although they occupy a smaller area compared to land
and oceans, freshwaters are home to a relatively high propor-
tion of
species
(animals, plants, and
microorganisms
),
with more per unit area than any other
environment
(10%
more than land, and 15% more than oceans). However, some
areas, such as the Amazon, Congo, Nile, and Mekong basins
are densely populated with species and are called “hotspots.”
In the United States, legislation of water diversion
and reclamation programs initially focused on agricultural
development, job creation, and power generation. Eventu-
ally, the long-term environmental impact of some of these
big river projects became apparent as western
wetlands
disappeared and scores of migratory
salmon
and other
wild-
life
were designated endangered and threatened under the
Endangered Species Act
(ESA).
Diversion projects prevent migrating fish from re-
turning to their native upstream spawning grounds. The
California Department of Fish and Game estimates that
two-thirds of the winter-run chinook salmon that spawn in
the Sacramento River do not make it to the Pacific. Water
diversion channels can be difficult to navigate, and water
diversion pumps that feed the California Water Project kill
and maim a large percentage of the migrating population
each year. In addition, diversions for irrigation and residen-
tial water diversion lowers the water level of the river, slowing
the progress of the salmon and increasing river water temper-
ature to inhospitable levels. Despite the integration of fish
lifts and fish ladders into modern dams, populations of native
fish stocks are still greatly depleted by dam structures.
In addition to the problem of depleted fish stocks,
migrating fish such as salmon and trout transport nutrients
from oceans to rivers. When this fish population declines, so
also does a significant amount of
nitrogen
and
phosphorus
,
which is typically released into rivers by decomposing car-
casses. This
nutrient
loss affects the
ecosystem
as well
as the fish supply. A renewed interest has been placed on
modifying diversion projects to recover river ecosystems and
biodiversity
.
The impact of water diversion products on habitats in
and around rivers, wetlands, and streams can be profound.
The U.S. Army Corps of Engineers estimates that there are
over 77,000 dams of significant size over 6 ft (1.8 m) in
the United States. Levees, dams,
shoreline armoring
, and
other diversion structures change the very geography, geol-
ogy, and
hydrology
of the river, influencing flow levels,
altering channels, and preventing natural
erosion
. These
structures also block the natural flow of
silt
and sediments.
The natural
floodplain
is frequently impacted, resulting in
a two-fold effect: destroying wetland ecosystems and elimi-