Water on Earth


On the earth's surface, 70% is covered by water. Of this water, 97% is contained in oceans as salt water, and is therefore not usable for drinking or irrigation.  Of the 3% that is freshwater, only 0.3% is easily accessible and clean enough to drink.  That means that of the massive stores of water we imagine across the globe, 99.7% are essentially unusable.
  • The result is that water must be conserved and used efficiently. Therefore, the need to manage water arises is a response to matching the supply of water to people with their domestic and industrial needs- needs such as household use, manufacturing, irrigation, recreation and navigation.

Water Scarcity 101

From the UN Food and Agricultural Organization, some basic facts on water and its scarcity worldwide.

The ways in which water is utilized at the regional scale.

There are three ways in which water is utilized at the regional scale:
  1. Water extraction
    • Irrigation of agriculture
    • Urban areas
  2. Generating Electricity
    • Hydroelectric power
  3. Recreational activities
    • Boating, swimming, etc.

Case study: The Colorado River
Located in the southwestern United States and northwestern Mexico, the Colorado River is a 2,330-kilometers long. The river is the primary source of water for a region that receives little annual rainfall. The Colorado River system, including the Colorado River, its tributaries , and the lands that these waters drain, is called the Colorado River basin. It drains a total area of 637,000 square kilometers. Today nearly 17 million people depend on the Colorado's waters. 
The Colorado River spans across 7 states and part of Mexico.
This article from the Smithsonian Institute discusses how the Colorado River, once one of America's largest, has been drastically reduced by dams for hydroelectric power, irrigation for agriculture and climate change.  Is this the direction in which the world is heading?  
Colorado River Runs Dry - Smithsonian Institute

1. Water extraction
  • Irrigation of Agriculture
    • Colorado River
      • Each year, an estimated 18,000 million cubic meters of water is extracted from the Colorado River
      • States that are extracting water are: California, Arizona, New Mexico, Colorado, Utah, Nevada and Wyoming. Mexico also extracts the rivers water.
      • 90% of extracted water on the Colorado River is used for agriculture
      • Since 1922, each State on the Colorado River is a part of the Colorado River Compact In which each state is allocated a certain amount of water it is allowed to extract per year
        • Though this is a good way of limiting the water withdrawn from the river, an editorial in the New York Times explains that the water extracted is based on measurements in 1922. Since then, water levels have dropped, and in order to keep up to date with the river flow, states need to intensify water conservation efforts.
        • The Colorado River's Future - The New York Times
      • The Colorado River evidently a very important source of accessible, drinkable water
    • Pros
      • An importance source of agricultural irrigation
    • Cons
      • Over extraction can lead to water scarcity
      • LEDCs sometimes have inefficient irrigation systems, which involve:
        • silt entering the system
        • over-watering
        • water escaping
        • salinisation of water and fields
        • run-off of pesticides and chemical fertilisers resulting in polluted water
  • Urban usage
    • Colorado River
      • 10% of extracted water is left for urban uses
      • Used for municipal drinking water
    • Pros
      • An importance source of drinking water in cities
    • Cons
      • The Colorado River contains large amounts of solids (mostly salt) in the water
      • Salinity increases downstream primarily due to agriculture, evaporation, and the leeching of salts from soils - As a result,  expensive desalination plants must be built
      • In LEDCs, water supplies are often very polluted and the government lacks the funds to upgrade water treatment facilities
Numerous dams were built on the Colorado and its tributaries during the twentieth century. The purpose of these dams was primarily to generate hydro electricity, control floods, and provide recreational opportunities. They also store water during wet times for use during the dry months and, in some cases, during dry years.

2. Hydro Dams
  • Colorado River
    • Many Hydro dams have been built on the Colorado River including: The Glen Canyon Dam, Hoover Dam, Parker Dam and Davis Dam
    • The basin dams are able to store more than 86 billion cubic meters of water along with producing an estimated 10 million mega-watt hours annually
  • Pros
    • Storage of water on the river
    • Produces power
    • Controls flooding and provides an area for recreational activities
    • Renewable energy source
  • Cons
    • Hydroelectric power production require flooding of entire valleys and scenic areas.
    • Disrupts natural seasonal changes in he river, and ecosystems can be destroyed.
    • Ends flooding that help to clean out the silt in rivers, causing them to clog 
    • Dams are expensive
    • Due to drought dams may become useless, or produce much less power than originally planned.
The Glen Canyon Dam


3. Recreational Activities
  • Colorado River
    • The Colorado River is a place for a wide range or recreational activities like:
      • Boating
      • Canoeing
      • Fishing
      • White water rafting
    • There are also many on-land activities that rely on the river like:
      • Hiking
      • Biking
      •  Camping
      • Horseback riding
  • Pros
    • These activities are vital to the local economy. They stimulate tourism and without the river many small towns would vanish.
  • Cons
    • Large amounts of tourism or recreation can disturb the local areas and wildlife
White Water Rafters on the Colorado River
For another case study on how water is used at the regional scale, read about the Karakum Canal in Turkmenistan in the Planet Geography Textbook.

References:
Planet Geography Textbook - Stephen Codrington

Hoover Dam - Hydroelectric Power on the Colorado River

The Hoover Dam, one of the world's largest, is an example of water use on the Colorado River. The dam provides electricity to thousands of people, but has massive environmental effects. By controlling the flow of water, annual flooding has ended, and the salinity levels of Lake Mead at its base is changing. As a result, the ecosystems are affected, with 4 species of native fish now listed as endangered.

Environmental and Human Factors Affecting Patterns and Trends in Physical Water Scarcity and Economic Water Scarcity

The Need to Manage Water is Becoming More Pressing as Demand Increases



  • By 2025, water use for domestic, industrial and livestock purposes is projected to increase by at least 50%.
  • This significant increase will severely limit the water available for use in irrigation, which will increase by just 4%, restricting increases in food production in some parts of the world.
  • 1/3 of the world's population live in countries that are experiencing moderate to high stress on their water supplies.
  • Much of the increase for demand of water will occur in LEDCs or developing countries.

This article from the BBC discusses the pending scramble for water, due to increasing physical water scarcity.  Water-poor but cash-rich nations are looking to purchase territory in LEDCs to have renewed access to water with which they may become self-sufficient in food production and water supplies.  The Pending Scramble for Water - BBC News

  • Physical Water Scarcity occurs in places where the demand for water exceeds the supply
    • This is most common in arid and semi-arid areas where rainfall is low and river flow fluctuates
    • As seen in the map above, this includes North Africa, the Middle East, and North-Central Asia.  Similar issues face the Southwest of the United States, Northern Mexico, and Southern Australia

  • Human and Environmental Factors:
    • Location
      • The environment of the region; areas with low rainfall, low groundwater supplies, few lakes or rivers, and generally arid conditions have difficulties accessing water, simply because it is not readily available
      • An example is Saudi Arabia, where desert conditions mean that there is little accessible fresh water.  Most water must be removed from the ocean and desalinated, a costly procedure.
    • Depletion
      • Increasing human use has resulted in limited water supplies shrinking continuously (especially groundwater supplies, which in essence are a non-renewable resource, and rivers that are diverted for a variety of reasons)
      • Competing agricultural, industrial and human interests.  In many nations, increasing population results in a corresponding need for increased agricultural and industrial production.  As all three grow, and water supplies do not, there is invariably a conflict.  This is only in cases where the environment dictates low existing water supplies, thus affects mainly the nations coloured in red on the map above.
    • Waste and Misuse
      • In LEDCs, 60% to 75% of water used in irrigation is lost through leakage, evaporation or runoff, and is never used for its intended agricultural purpose. In regions with limited water supplies, this is critical.
      • Some urban areas insist on using water for ornamental purposes (ex. fountains), when much water is lost to evaporation or leakage.  Similarly, water used to irrigate ornamental plants, especially grass, severely affects many wealthy nations (for causes like golf courses)
The Gobi Desert in Asia is a region with very low water supplies,
yet a growing population in areas like Western China.
This article discusses the increasing physical water scarcity in the Middle East resulting from declining water supplies.  The authors credit global warming for continuing scarcity, and claim that the future holds only more danger and difficulty in accessing water for these regions.  Climate Change Threatens Mideast Water Supply - The Montreal Gazette

  • Economic Water Scarcity occurs when water is available but some people cannot afford to obtain it for reasons of poverty
    • This is most common in LEDCs, especially among poor living in shanty settlements in the cities
    • This includes Sub-Saharan Africa, and some parts of Southern and Southeast Asia.

  • Human and Environmental Factors:
    • Price of Water
      • As mentioned under the section referring to Cost in the "Access to Clean Drinking Water" post of this blog, governments sometimes purposely raise the cost of water to cajole consumers not to waste it.  In LEDCs, water is difficult to attain or unaffordable to begin with, and this causes severe issues.
    • Distance and Cost
      • Water supplies may not be in accessible locations (namely in many African villages, where women are forced to walk miles to have access to fresh water)  The loss of income associated with this, or perhaps the price of water once it is found, results in economic scarcity
    • Pollution
      • The cost of technology to clean water makes it impossible for many people to gain access to clean water, resulting in the use of water polluted by chemicals, household materials or human and animal waste, or no water at all
    • Societal Factors
      • Housing, especially in slums or shanty towns, means that water is difficult for regular people to access, due to nonexistent household connections (pipes) or wells.  Wars or conflicts often result in regions already affected by limited water supplies, disrupting access to that water.
Indian women carrying water long distances from the source
to their homes.  This restricts their access to water.
The countries listed above are all subject to economic water scarcity.


Access to Safe Drinking Water

Access to safe drinking water is a major concern, and it's addressed in one of the targets of the Millennium Development Goals - to halve the proportion of people without sustainable access to safe drinking water and basic sanitation, by 2015.


Some terminology:
  • Drinking Water is water that is used for domestic purposes, including drinking, cooking and personal hygiene.
  • Access to drinking water means that the source of water is less than 1 kilometre away from the place it will be used. It is possible to obtain at least 20 litres per person per day on a reliable basis.
  • Safe drinking water is water with bacterial, chemical and physical characteristics that meet World Health Organization guidelines or national standards for drinking water quality.
  • Access to safe drinking water is the proportion of a population using improved drinking water sources.  This includes access to household connections (piped water), public standpipes (similar to free-standing faucets or pumps), bore hole (similar to a well, but with pipes), dug wells, protected natural springs, or clean rainwater.


Proportion of the population without access to safe drinking water


Unclean or unsafe drinking water is highly dangerous, namely due to the risk of disease.  Cholera, schistosomiasis, hookworm (and other parasites), hepatitis, and even common diarrhoea are diseases commonly contracted from dirty water.  In LEDCs, where people are most likely to encounter unsafe drinking water, and where healthcare is often lacking, these diseases can prove deadly.


Read this article, by Jan Eliasson, former Swedish ambassador to the US and President of the UN General Assembly, and Susan Blumethal, former assistant surgeon general of the US.  They discuss access to clean water across the globe, namely the factors and effects of this critical issue.  
Dying For a Drink of Clean Water - The Washington Post

So the question remains - with the dangers so clear, why isn't access to safe drinking water universal?  What factors affect access to clean water for household purposes?
  • Water supplies are unevenly distributed
    • The world has abundant supplies of freshwater, yet these supplies are unevenly distributed between, and even within countries.
  • Stores of water are being depleted
    • Populations are growing at such a rapid rate that easily accessible surface water stores are being depleted across the globe
    • 1/3 of the earth's population lives in countries whose water supplies are under moderate to high stress; their consumption levels exceed available supply by 20%
    • By 2025, this proportion will rise to 2/3 of the global population
  • Competition with industry and agriculture
    • Manufacturing is increasing to such an extent that it is predicted global water use by industrial sources will double from 2000 rates by 2025
    • Agriculture currently makes up a staggering 70% of water use, and will increase between 50% and 100% by 2025
  • Pollution
    • Pollution of water supplies is a huge issue, as it makes existing clean water supplies unusable
    • In LEDCs, where water scarcity is worst felt, the need to industrialize sidelines the preservation of the integrity of clean water
      • See this article about governments and corporations, even in MEDCs like the United States, ignore the right of their citizens to access clean water. 
      • Toxic Waters - The New York Times
    • Problems like eutrophication (abundant growth of algae), acidification, heavy metals and persistent organic pollutants (POPs, such as the pesticide DDT which is subject to biomagnification/bioaccumulation, and can be deadly to those animals high up in the food chain)
    • When pollutants descend into the groundwater, dilution becomes very slow, and purification very expensive.  This is especially dangerous in Asian countries, where over 50% of water supplies come from groundwater
  • Cost
    • Conflicts between urban and rural water users may result in government legislation and quotas (ex. USA and Australia), or the deliberate increase in water price so as to discourage waste or pollution
    • This is difficult for those living in LEDCs, where clean water is already difficult to find

Industrial and agricultural interests compete with people for access to clean water.

An Indonesian family uses polluted water to bathe.
A TED Talk discussing the ability to convert dirty water into drinkable water.  Technology like this could spell success for millions of people currently suffering without access to clean water.
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