Advanced Level Geography @ SJP
GG5: Sustainable Water Supply –
Key Terms and Concepts
Sustainable Water Supply Issues - Word Bank
Key Term/Concept
Aquifer
Arizona
Definition
An aquifer is an underground layer of waterbearing permeable rock or unconsolidated
materials (gravel, sand, silt, or clay) from
which groundwater can be usefully extracted.
For example the Arizona aquifer and Ogallal
aquifers in the US. The Arizona aquifer is a
fossil aquife, however, see fossil aquifer
below.
The key case study of a region experiencing
water stress in the US. Located in the South
West of the US (be able to draw key location
map) it is one of the desert (Sonoran) states
whose population has grown rapidly in the
last 30 years (est at 6.5 million in 2008) due
to a high level of in-migration. Known as one
of the sun-belt states – it has attracted
footloose high-tech industries.
ADWR – Arizona Department of Water
Resources
AWBA – Arizona Water Banking
Authority
Established in 1980 to manage the state’s
most precious resource – its water. The
primary mission of ADWR is to ensure an
adequate quantity of water of adequate
quality for Arizona’s future. This means it has
to formulate and implement policies to
increase supply and control demand.
The Arizona Water
Banking Authority
(AWBA; Water Bank) was
established in 1996 to
increase utilization of the
state’s Colorado River
entitlement and develop
long-term storage credits for the state. AWBA
stores or “banks” unused Colorado river water
to be used in times of shortage to secure
water supplies for Arizona.
Each year, the AWBA pays the delivery and storage costs to bring Colorado River water into
central and southern Arizona through the Central Arizona Project canal. The water is stored
underground in existing aquifers (direct recharge) or is used by irrigation districts in lieu of pumping
groundwater (indirect or in-lieu recharge). For each acre-foot stored, the AWBA accrues credit that
can be redeemed in the future when Arizona’s communities or neighbouring states need this
backup water supply.
The Central Arizona Project (CAP) is a 336
CAP – Central Arizona Project
mi (541 km) diversion canal in Arizona in the
United States. The aqueduct diverts water
from the Colorado River from Lake Havasu
City behind the Parker Dam into central and
southern Arizona. The CAP is the largest and
most expensive aqueduct system ever
constructed in the United States. CAP is
managed and operated by the Central
Arizona Water Conservation District
(CAWCD). It is a 336-mile (approx 500km)
long system of aqueducts, tunnels, pumping
plants and pipelines and is the largest single
resource of renewable water supplies in the
state of Arizona. It is a $4 billion inter-basin
water transfer project. You must be able to
evaluate this water management scheme i.e.
a cost/benefit analysis.
China
Chongqing
Colorado River
China is your key case study of a LEDC that has
adopted a western-centric approach to its water
management issue in the Yangtze Valley. It has used
the mega-dam approach by building the world’s largest
super-dam – the Three Gorges.(see Three Gorges
below). This multi-purpose dam project has been
particularly controversial so you must be able to
evaluate its +/- aspects and its sustainability.
Chongqing was separated from Sichuan province and
made into a municipality in March 1997 in order to
accelerate its development and subsequently China's
relatively poorer western areas (see China Western
Development or Go-West’ strategy). It is located at the
far western end of the Three Gorges Reservoir and it
is expected to act as an economic catalyst in the
development of China’s interior – central/western
provinces – that have lagged increasingly further
behind the rapidly developing coastal zone.
The Colorado River or the Red River, is a river in the
southwestern United States and northwestern Mexico,
approximately 2,330 km (1,450 US miles) long,
draining a part of the arid regions on the western slope
of the Rocky Mountains. The natural course of the river
flows into the Gulf of California, but the building of
major dams and high level of water abstraction by
neighbouring states has desiccated the lower course
of the river in Mexico such that it no longer consistently
reaches the sea.
Colorado River Compact
The Colorado River Compact is a 1922 agreement
among seven U.S. states in the basin of the Colorado
River in the American Southwest governing the
allocation of the river's water among the parties of the
interstate compact.
The compact divides the river basin into two areas, the
Upper Basin (comprising Colorado, New Mexico, Utah
and Wyoming) and the Lower Basin (Nevada, Arizona
and California). The compact requires the Upper Basin
states to deliver water at a rate of 7.5 million acre feet
per year (293 m³/s), averaged over a moving ten-year
average. Based on historical rainfall patterns, the
amount specified in the compact was assumed to
allow a roughly equal division of water between the
two regions. The states within each basin were
required to divide their 7.4 million acre foot per year
(289 m³/s) share allotment among themselves. The
compact enabled the widespread irrigation of the
Southwest, as well as the subsequent development of
state and federal water works projects such as the
CAP.
Common property water
rights
Groundwater use from Arizona aquifer is based on the
principle of common property resource rights i.e.
subsurface water can be abstracted by whoever owns
the land above such water.
An area of land drained by a river and its tributaries
and its boundary is marked by ridges of highland to
create a watershed. You must be able to draw the
drainage basin system (open) diagram and refer in
detail (+ draw key map) to Colorado River, Yangtze
River and Niger Rivers = key case studies.
A period of below-average precipitation. You studied
the problems of drought in Arizona and Mali. Drought
is a ‘creeping hazard’ associated with high
atmospheric pressure and it has different components
(GG4 synoptic link) i.e. meteorological, agricultural,
hydrological and socio-economic drought.
Lake Faguibine is located in the Sahelian−sub desert
zone to the west of Timbuktu in northern Mali. Annual
precipitation in the Faguibine area is in the range of
250 mm/yr, with the rainy season beginning in midJune and lasting 3 to 4 months. When full, the lake is
among the largest in West Africa − an estimated 590
Drainage Basin
Drought
Faguibine (lake)
Fossil aquifer
Gila (River)
Grey water
square kilometers in 1974 − and is an important
source of water for the surrounding area. In the late
1980s Lake Faguibine essentially dried up, making the
traditional economic practices of fishing, agriculture
and pastoralism difficult or impossible. Reduction in
the discharge of the Niger River is one of the causal
factors.
Fossil water or paleowater is groundwater that has
remained in an aquifer for millennia. Water can rest
underground in aquifers for thousands or even millions
of years. When geologic changes seal the aquifer off
from further "recharging," the water becomes trapped
inside and then becomes known as fossil water. The
Ogallala Aquifer and Arizona Aquifer Systems are
among the most notable of fossil water reserves.
Extraction of fossil water is sometimes referred to as
water mining because it is a non-renewable resource.
Groundwater depletion is a major problem in Arizona
as a result of unsustainable use resulting in
subsidence problems.
The Gila is a tributary of the Colorado River, 650 miles
(1,044 kilometers) long, in the southwestern states of
New Mexico and Arizona. The Gila River and its main
tributary, the Salt River, would both be perennial
streams carrying large volumes of water, but irrigation
and municipal water diversions turn both into usually
dry rivers. Below Phoenix to the Colorado River, the
Gila is usually either a trickle or completely dry.
Greywater, is non-industrial wastewater generated
from domestic processes such as dish washing,
laundry and bathing. Greywater comprises 50-80% of
residential wastewater. Greywater comprises
wastewater generated from all of the house's
sanitation equipment except for the septic tank (water
from toilets is blackwater, or sewage). Greywater is
distinct from blackwater in the amount and composition
of its chemical and biological contaminants (from feces
or toxic chemicals). Greywater gets its name from its
cloudy appearance and from its status as being neither
fresh (white water from groundwater or potable water),
nor heavily polluted (blackwater). According to this
definition wastewater containing significant food
residues or high concentrations of toxic chemicals from
household cleaners etc. may be considered "dark
grey" or blackwater.
In recent years concerns over dwindling reserves of
groundwater and overloaded or costly sewage
treatment plants has generated much interest in the
reuse or recycling of greywater, both domestically and
for use in commercial irrigation. However, concerns
over potential health and environmental risks means
that many jurisdictions demand such intensive
treatment systems for legal reuse of greywater that the
commercial cost is higher than for fresh water. The
ADWR is promoting greywater use as one of its goals
to achieve a sustainable water future.
Groundwater
Groundwater comes from rain, snow, sleet, and hail
that soaks into the ground. The water moves down into
the ground (infiltration and percolation) because of
gravity, passing between particles of soil, sand, gravel,
or rock until it reaches a depth where the ground is
filled, or saturated, with water. The area that is filled
with water is called the saturated zone and the top of
this zone is called the water table. In Arizona there is a
fossil (non-rechargeable) aquifer that has been
pumped in an unsustainable manner to supply the
needs of the cities of Phoenix and Tucson with their
exponential growth in water use. This has caused the
water table to fall and the ground to subside. The
ADWR and AWBA are now trying to recharge the
aquifers using Colorado River water from the CAP and
store water for the future.
Groundwater overdraft
Groundwater overdraft occurs when water removal
exceeds water recharge. The slow natural recharge
rate of most aquifers and high rate of pumping has led
to groundwater overdrafts in most irrigated areas of the
U.S. over the past century. Impacts associated with
groundwater overdraft are the results of falling water
levels as the water stored in an aquifer is depleted.
Groundwater overdraft is a significant problem
because it results in land subsidence and
desertification. In Arizona, land subsidence due to
groundwater overdraft is a serious problem because
the water supporting the land is being mined. Arizona
is mining groundwater at almost twice the natural
replenishment rate, and 90% of this water is used by
irrigation (Wolman 1987). Arizona has become the
first state to limit the pumping of ground water.
Lake Havasu is a large reservoir behind Parker Dam
on the Colorado River, on the border between
California and Arizona. The lake's primary purpose is
to store water for pumping into two aqueducts – the
Central Arizona Project and California Aqueduct.
Havasu (Lake)
Hydropolitical Conflict
Mali
In Africa, most major rivers, freshwater lakes, and
aquifers are shared by two or more countries. These
nations are becoming increasingly vulnerable to hydropolitical conflict, and their vulnerabilities are made
more acute by climatic variations in precipitation,
increasing urbanization, industrialization and
environmental degradation. Disputes over water
resources are likely to escalate in the future as water
stress increases as a result of climate change. In the
South-West United States the there is potential for
hydro-political conflict/dispute between the US and
Mexico and within the US between competing states
e.g. California, Arizona, Nevada etc.
Your case study of an LEDC (LLEDC) in Sahelian
Africa that experiences major water stress. This is the
key synoptic link for drought hazard and management
studied in GG4. Be able to draw key map of Mali and
main geographic features/places. Here there is a need
to promote more traditional forms of water
conservation and management e.g. rain-water
harvesting, stone bunds, xerophytic planting etc.
Niger River:
The Niger is the principal river of western Africa, extending about 4200 km. Its drainage basin is
2.2m square kilometres in area. ts source is in the Guinea Highlands in southeastern Guinea. It
runs in a crescent through Mali, Niger, on the border with Benin and then through Nigeria,
discharging through a massive delta, known as the Niger Delta. The Niger is the third-longest river
in Africa, exceeded only by the Nile and the Congo River. This vital source of life needs to be
managed by international agreement and presents major potential for hydropolitical conflict
because of the dryness of the environment it flows through, plus the growing threat from climate
change.
The Ogallala Aquifer, also known as the High Plains
Ogallala Aquifer
Aquifer, is a vast yet shallow underground water table
aquifer located beneath the Great Plains in the United
States. One of the world's largest aquifers, it covers an
area of approximately 450,000 km in portions of the
eight states of South Dakota, Nebraska, Wyoming,
Colorado, Kansas, Oklahoma, New Mexico, and
Texas. About 27 percent of the irrigated land in the
United States overlies this aquifer system, which yields
about 30 percent of the nation's ground water used for
Parker Dam
Phoenix
Salt (River)
Sonoran Desert
Subsidence
irrigation. In addition, the aquifer system provides
drinking water to 82 percent of the people who live
within the aquifer boundary. This aquifer is being used
in an unsustainable manner as demand grows but
recharge is very slow due to the fact that it is a fossil
aquifer.
Parker Dam is a concrete arch dam which spans the
Colorado river, at a point 155 miles (250 km)
downstream of Hoover Dam. The dam's primary
functions are to act as a reservoir, and to generate
hydroelectric power. The dam straddles the border
between California and Arizona. The reservoir behind
the dam is called Lake Havasu and can store 647,000
acre-feet (798,000,000 m³) or over 210 billion US
gallons of water. This water supplies the Californian
and Central Arizona Aqueducts.
Phoenix is the capital and largest city in the U.S. state
of Arizona, as well as the fifth most populous city in the
United States – with a metropolitan population of 4.5
million. The exponential growth of this metropolitan
area has placed enormous stress on the states water
resources, especially its groundwater stores. For years
it has drawn its water from the surface stores of the
Gila and Salt Rivers and the Arizona Aquifer. Future
water shortage is now being monitored and managed
through the Central Arizona Project and its
Groundwater Management Programme i.e. Water
banking for the future.
The Salt River is the main tributary of the Gila River,
approximately 322 km (200 mi) long, in central Arizona
in the United States. It has its confluence with the Gila
at approx 25km south west of the city. The discharge
has decreased over time due to surface water
abstraction for irrigation and urban/municipal use.
The Sonoran Desert (sometimes called the Gila
Desert after the Gila River or the Low Desert in
opposition to the higher Mojave Desert) is a North
American desert which straddles part of the United
States-Mexico border and covers large parts of the
U.S. states of Arizona and California and the northwest
Mexico. The largest city in the Sonoran Desert is
Phoenix, Arizona, U.S.A., with a 2008 metropolitan
population of about 4.5 million. This metropolitan area
in central Arizona is one of the fastest-growing
metropolitan areas in the United States. In the North
Phoenix area, desert is losing ground to development
at a rate of approximately 4,000 square metres
(0.99 acres) ) per hour.The next largest cities are
Tucson, in southern Arizona, U.S.A., with a metro area
population of around 1 million.
Land subsidence has plagued many portions of
Arizona since highly efficient means of groundwater
extraction were developed in the early to mid 1900s.
As groundwater extraction exceeded natural aquifer
recharge, groundwater levels dropped by as much as
500 feet and the dynamics needed to initiate land
subsidence were put in place. With the increasing
occurrence of land subsidence and resultant earth
fissures in certain areas of the state, the
consequences of dropping water tables become
distinct, physical and sometimes dramatically visible.
Land subsidence and fissuring provide tangible
evidence that the over withdrawal of groundwater has
geological as well as public policy consequences.
Three Gorges Dam
The Three Gorges Dam is the world’s largest hydropower project and most notorious dam. The
massive project sets records for number of people displaced (more than 1.2 million), number of
cities and towns flooded (13 cities, 140 towns, 1,350 villages), and length of reservoir (more than
600 kilometers). The project has been plagued by corruption, spiraling costs, technological
problems, human rights violations and resettlement difficulties.
The environmental impacts of the project are profound, and are likely to get worse as time goes on.
The submergence of hundreds of factories, mines and waste dumps, and the presence of massive
industrial centers upstream are creating a festering bog of effluent, silt, industrial pollutants and
rubbish in the reservoir. Erosion of the reservoir and downstream riverbanks is causing landslides,
and threatening one of the world’s biggest fisheries in the East China Sea. The weight of the
reservoir's water has many scientists concerned over reservoir-induced seismicity. Since 2007,
Chinese scientists and government officials have become increasingly concerned about the
environmental and social impacts of the project
The Three Gorges Dam is a model for disaster, yet the Chinese government is replicating this
model both domestically and internationally. Within China, huge hydropower cascades have been
proposed and are being constructed in some of China’s most pristine and biologically and culturally
diverse river basins - the Lancang (Upper Mekong) and upstream of Three Gorges Dam on the
Yangtze River and tributaries.
Governments and companies from around the world have helped fund and build the Three Gorges
Dam. Yet through this project, China has acquired the know-how to build large hydropower
schemes, and is now exporting similar projects around the world.
While Three Gorges is the world’s biggest hydro project, the problems at Three Gorges are not
unique. Around the world, large dams are causing social and environmental devastation while
better alternatives are being ignored.
International Rivers protects rivers and defends the rights of the communities which depend on
them. We monitor the social and environmental problems of the Three Gorges Dam, and work to
ensure that the right lessons are drawn for energy and water projects in China and around the
world.
This article is clearly one sided and was written by an organisation called International Rivers.
Our mission: To protect rivers and defend the rights of communities that depend on them. We oppose
destructive dams and the development model they advance, and encourage better ways of meeting people’s
needs for water, energy and protection from damaging floods. We seek a world in which rivers and the life they
support are valued, and where all people have a voice in decisions affecting their lives and livelihoods. We work
toward a world where everyone has access to clean water and energy, and where development projects neither
degrade nature nor destroy communities. Based in five continents, our staff has expertise in dams, energy and
water policy, climate change, and international financial institutions. We work with a global network of damaffected people, environmentalists, human rights advocates and experts who are committed to fighting
destructive river projects and promoting better alternatives. International Rivers (formerly known as
International Rivers Network or IRN), was founded in 1985 and the focus of our work is in Latin America, Asia
and Africa.
Click here for hyperlink to International Rivers and some useful video clips that can be used to help you
evaluate the negative aspects of mega dams in general and Three Gorges specifically or if it does not
work use this address:
http://internationalrivers.org/en/node/287
Obviously, you need to be able to provide a more balanced view of this water management project
if you are asked to evaluate it. Clearly the project brings major benefits in terms of flood control in
the Lower Yangtze and HEP generation to fuel China’s exponential economic growth. This will help
to reduce China’s carbon footprint – it is now the world’s biggest producer of greenhouse gases
(C02) due to its dependence on its own high sulphur content coal. Use your file notes to help you
develop the arguments in favour of the Three Gorges. However, could some of these objectives
been achieved by using alternative, smaller-scale more sustainable projects i.e. micro-dams,
afforestation etc.
Tucson
Water Balance Equation
The second largest city in Arizona with 1.5 million
people and the end point of the CAP aqueduct.
This is synoptic link to GG1 and you should be able to
apply this in an exam answer:
P=E+S+D
The problem of growing water scarcity can be
exemplified by MEDC case study of S W United States
(focus on Arizona) and LEDC case study of Mali. Both
experience water stress. Arizona is the only US state
where the demand for water exceeds the available
supply which means it experiences water overdraft
from its rivers and groundwater stores. The demand
for water is 10.8billion gallons/day but the supply is
10.3bg/d. In order to manage this problem the ADWR
and AWBA have put in place a number of strategies to
increase supply and to manage demand (see below).
Use the see-saw diagram of Arizona to illustrate the
imbalance with demand outweighing supply. To
manage demand needs to be controlled (water
efficency and conservation)and supply increased
(CAP).
The Yangtze River is the longest river in China and
Asia, and the third-longest in the world, after the
Amazon in South America and the Nile in Africa.
Water Stress
Yangtze (River)
The river is about 6,385 km long and flows from its
source in Qinghai Province in the Tibetan Plateau
eastwards into the East China Sea at Shanghai.
The Three Gorges Dam and reservoir is located on the
river upstream from Wuhan and it stretches upstream
to Chongqing.
Xerophytic plants and
xeriscaping.
Plants that have adapted to survive in relatively dry
conditionst are called xerophytic. In Arizona the ADWR
has been promoting water conservation through
policies that promote the use of xerophytic vegetation
in residential and municipal.urban landscaping
projects. This is known as xeriscaping.
Words that were not inserted at right place.
Laser levelling
Land Leveling through Laser Leveler is one such proven technology that is highly useful in
conservation of irrigation water.
Laser land leveling is leveling the field within certain degree of desired slope using a guided laser
beam throughout the field. Unevenness of the soil surface has a significant impact on the
germination, stand and yield of crops. Farmers also recognize this and therefore devote
considerable time resources in leveling their fields properly. However, traditional methods of
leveling land are cumbersome, time consuming as well as expensive.
Effective land leveling is meant to optimize water use efficiency, improve crop establishment,
reduce the irrigation time & effort required to manage crop. This is being used in Arizona to
reduce wastage of water due to inefficient irrigation practices.
Micro-irrigation
Rainwater harvesting
Conventional irrigation systems, such as channel
irrigation and wild flooding tend to waste water as large
quantities are supplied to the field in one go, most of
which just flows over the crop and runs away without
being taken up by the plants.
Micro irrigation is an approach to irrigation that keeps
the water demand to a minimum. The drip irrigation
system works so that water goes straight to the roots
of the plants.It has been driven by commercial farmers
in arid regions of the United States of America and
Israel. Typically, these commercial irrigation systems
consist of a surface or buried pipe distribution network
using emitters supplying water directly to the soil at
regular intervals along the pipework. They can be
permanent or portable.
Rainwater harvesting is the gathering, or
accumulating and storing, of rainwater.
Traditionally, rainwater harvesting has been practiced
in areas where water exists in plenty, and has provided
drinking water, domestic water, water for livestock,
irrigation and a way to increase ground water levels.
There are many types of systems to harvest rainwater.
Notable systems are systems for runoff rainwater (eg
hillside run-off that is trapped behind mini-stone dams
(bunds) and rooftop rainwater harvesting systems.
These are more sustainable low tech solutions for
people living in marginal environments in LLEDCs
such as Mali.
Water efficiency – one of the
main objectives of ADWR to
achieve a sustainable water future.
Though the two are often used interchangeably, there
is a difference between water conservation and water
efficiency. Water efficiency differs from water
conservation in that it focuses on reducing waste It
also emphasises the influence consumers can have in
water efficiency by making small behavioural changes
to reduce water wastage and by choosing more water
efficient products. Examples of water efficient steps
includes fixing leaking taps, taking showers rather than
baths, installing displacements devices inside toilet
cisterns, and using dishwashers and washing
machines with full loads. These are things that fall
under the definition of water efficiency, as their
purpose is to obtain the desired result or level of
service with the least necessary water.
Water Pricing
Some groups believe that the ADWR should increase
water prices to users so that they are paying the true
cost for water supply rather than the subsidized price.
Use the water supply and demand graph to show how
the current prices being paid are subsidized so water
is not being used efficiently. Raising the price to
consumers will force them to adopt more efficient use
practices and thus reduce water waste. Learn the
graph we used for this – using the subsidized and the
true market price.