There are different phrases used to describe the different water issues in the world.
Different organisations or individuals may describe different things when using these phrases, and may use them in different contexts.
To clear up some of the potential uncertainty or confusion, what we’ve done in this guide is give a unofficial definitions of each phrase individually, and also relative to each other.
*Note – separate water issues outside of the scope of this guide are 1. Natural disasters involving water such as floods, and 2. Access to clean and safe drinking water, and basic sanitation and hygiene (a common issue to underdeveloped or developing regions)
Summary – Global Water Issue Phrases
Global water issues generally revolve around these key problems:
- Quantity of water supplies (volume of available fresh water supplies, and the ratio of water being withdrawn and consumed vs the water resources being renewed)
- Quality of water supplies (whether water is in adequate condition for it’s end use – for example, drinking water vs water used for irrigation … potable vs non potable water)
- Access to water supplies (being able to extract, treat, transport and deliver water to it’s end use)
The different phrases used to describe different aspects of these problems are:
- Water Availability – relates to quantity
- Water Stress – relates to quantity
- Water Scarcity – relates to quantity
- Water Shortage – relates to quantity
- Water Access – relates to quantity (mostly for developing and underdeveloped regions though)
- Water Pollution & Contamination – relates to quality, but also affects quantity
- The Water Crisis – relates to access, and quantity
- Water Security – general water phrase
- Water Risk – general water phrase
Water availability is the water available to withdraw or consume from a water supply resource in a particular geographic region. This could be water from a surface water source (like a river or lake), or ground water source for example.
Water that is not available (at least not immediately without further technology or treatment methods) is water such marine water, brackish water, frozen water, and some types of underground water.
Non available water can also include rainfall that doesn’t inflow into a usable water supply source (because it evaporates, drains into a non usable water source, or is transpired by plants).
The mdba.gov.au resource has a good explanation of Australia’s water availability.
Water access usually refers to basic access to safely managed and clean fresh water resources – which people can drink, or use for other uses such as household, industry or agricultural activities.
Water access is critical for both drinking water, and socio-economic development.
Water access usually has three main barriers:
- Physical Water Access – only available water can be accessed. Some water can’t be accessed because of physical limitations such as being too isolated, or frozen
- Economic Water Access – having the financial resources to invest in water infrastructure and systems to extract, treat, transport and deliver the water to the end user
- Political/Institutional – inadequate political or institutional management of water access services and infrastructure
Water access differs by region and country.
For example, a developing region may use simple water wells to extract drinking water from the ground, whilst a developed region may have full water treatment plants, pipes, taps, and so on.
Water stress is a term used to describe the ratio of water demand (withdrawals) to water supply at any one time, and also, how much water resources may be remaining.
High water stress is an indicator that water demand and withdrawals might be outpacing renewal rates of a water supply source (a dam, a river, a ground water aquifer, and so on), and also that water supplies are usually trending towards being lower and lower.
Low water stress is an indicator that water supply renewal rates might be outpacing withdrawal/consumption rates, and that water supplies might be higher and not as much of a concern.
Countries with dry climates (low or variable rainfall), or that have low natural fresh water resources with growing populations and increasing demand might be in the highly water stressed country category.
Other descriptions of water stress are:
- Water stress is the ratio of total withdrawals to total renewable supply in a given area. A higher percentage means more water users are competing for limited water supplies, and therefore that area/country is more stressed
- Compared to water scarcity, water stress is a more inclusive and broader concept. It considers several physical aspects related to water resources, including water scarcity, but also water quality, environmental flows, and the accessibility of water
- Water stress is defined based on the ratio of freshwater withdrawals to renewable freshwater resources.
- Water stress does not insinuate that a country has water shortages, but does give an indication of how close it maybe be to exceeding a water basin’s renewable resources.
- If water withdrawals exceed available resources (i.e. greater than 100 percent) then a country is either extracting beyond the rate at which aquifers can be replenished, or has very high levels of desalinisation water generation (the conversion of seawater to freshwater using osmosis processes)
The World Resources Institute (WRI) define baseline water stress based on the ratio of annual water withdrawals to renewable resources.
It defines water stress categories based on this percentage (% of withdrawals to renewable resources) as follows:
- <10% = low stress
- 10-20% = low-to-medium stress
- 20-40% = medium-to-high stress
- 40-80% = high stress
- >80% = extremely high stress
Wri.org defines a country using/withdrawing 80% or more of their total water supply as ‘highly water stressed’
Some of the countries projected to be most water stressed by 2040 (wri.org) are: Bahrain, Kuwait, Qatar, San Marino, Singapore, United Arab Emirates and Israel.
According to the UN:
- … the global average water stress is only 13 per cent [total withdrawal vs available water resources]
- [But,] 32 countries experience water stress between 25 per cent (when stress begins) and 70 per cent
- And, 22 countries are above 70 per cent and considered seriously stressed
Water scarcity is generally more extreme than water stress.
It could be described as ‘the lack of sufficient available water resources to meet the demands of water usage within a region’
At the point of water scarcity, the water demand (withdrawal) rate is usually exceeding the renewal rate of internal water resources, and the volume of available water at this point (usually around 20% of total capacity or lower) relative to demand is a concern.
So, where water stress is a sliding scale (from low to extreme), water scarcity is a phrase used to describe the point where a population may be experiencing high or extreme water stress.
Similar to water access, water scarcity can be described as physical (lack of water, or over consumption of water) or economic (lack of financial investment or good governance) water scarcity.
There’s several ways to measure or assess water scarcity.
Pacinst has one example of a measurement of water scarcity compared to water stress:
- If the amount of renewable water in a country is below 1,700 m3 per person per year, that country is said to be experiencing water stress; below 1,000 m3 it is said to be experiencing water scarcity; and below 500 m3, absolute water scarcity
- [At levels between 1,700 and 1,000 cubic meters per person per year, periodic or limited water shortages can be expected]
Globalwaterforum.org also outlines some ways to measure or assess water scarcity:
- 1. Using the ‘Falkenmark indicator’ or ‘water stress index’ – measure scarcity as the amount of renewable freshwater that is available for each person each year [to a region or population of people, such as a city]. This indicator uses the same indicators that Pacinst outlines above
- 2. Criticality ratio – define water scarcity in terms of each country’s water demand compared to the amount of water available; measuring scarcity as the proportion of total annual water withdrawals relative to total available water resources. Using this approach, a country is said to be water scarce if annual withdrawals are between 20-40% of annual supply, and severely water scarce if they exceed 40%
- 3. International Water Management Institute (IWMI) Approach – assess scarcity by considering each country’s water infrastructure (such as desalination plants and recycled water) as well as internal fresh water sources (such as surface and ground water sources), and measuring it against consumptive water use rather than total withdrawals, whilst also considering the adaptive capacity of a country by assessing its potential for infrastructure development and efficiency improvements.
- Using this approach, the IWMI classifies countries that are predicted to be unable to meet their future water demand without investment in water infrastructure and efficiency as economically water scarce; and countries predicted to be unable to meet their future demand, even with such investment, as physically water scarce.
- 4. Water Poverty Index – considers the role of income and wealth in determining water scarcity by measuring: (1) the level of access to water; (2) water quantity, quality, and variability; (3) water used for domestic, food, and productive purposes; (4) capacity for water management; and (5) environmental aspects. The complexity of this approach, however, means that it is more suited for analysis at a local scale, where data is more readily available, than on a national level.
Perth in Western Australia is an example of a city that experienced water scarcity, but has since addressed it with technology such as desalination and ground water replenishment (amongst other measures)
Note that is possible a city could be water stressed or have scarce supplies of non potable water, but actually have secure supplies of drinking water. So, identifying the type of water that is scarce is important.
Water scarcity and a shortage of water is often grouped as the same issue or event.
But, ‘water shortage’ is sometimes a phrase used to describe a specific type of water scarcity event where clean fresh water supplies are getting to low enough levels where extreme water restrictions (say, level 7 or 8 water restrictions – sometimes called ‘Day Zero’) have to be enforced, and municipal tap water has to largely be turned off.
Cape Town currently lives with stringent water restriction in terms of per capita per day allowances.
Water Pollution & Contamination
Water pollution and contamination initially impacts the quality of the water.
But, if water can’t be treated or purified, it also impacts quantity of water.
Water security is composed of two factors:
- A population having an adequate quantity and quality of water for all their needs
- That population and their water supplies being adequately protected from water related risks
Wikipedia.org defines water security as:
- … the reliable availability of an acceptable quantity and quality of water for health, livelihoods and production, coupled with an acceptable level of water-related risks
Countries with high water stress, who are experiencing water scarcity or a water shortage, or who experience high levels of water contamination and pollution, might be considered as having poor water security.
Countries with low water stress, high quantities of internal accessible fresh water resources, and have no foreseeable threat to the quantity or quality of their available water supplies in the future might be seen as having high water security.
Water Risk refers to the possibility [or probability] of an entity experiencing a water-related challenge (ceowatermandate.org)
A water related challenge can be a challenge like the ones listed above (e.g. water scarcity, water stress), but could also be other challenges like natural disasters affecting water supplies, water infrastructure leaking or being inadequate, and so on.
Pacinst has this to say on water risk:
- Companies and organizations and governments cannot gain robust insight into water risk unless they have a firm understanding of the various components of water stress (i.e. water scarcity, accessibility, environmental flows, and water quality), as well as additional factors, such as water governance
- Many water-related conditions, such as water scarcity, pollution, poor governance, inadequate infrastructure, climate change, and others, create water risk for many different sectors and organizations simultaneously
The Water Crisis
The ‘Water Crisis’ is the term used in two main ways:
1. To refer to the serious health crisis whereby people in mostly low income or underdeveloped regions lack access to basic water services such as clean and safe drinking water, and basic sanitation and hygiene. Nearly 1 million people die each year from water, sanitation and hygiene-related diseases which could be reduced with access to safe water or sanitation. Every 2 minutes a child dies from a water-related disease. Over one billion people in developing countries have inadequate access to clean water.
The significant challenge in many of the regions affected is low income, and/or poor institutional governance/management.
Read more in these guides:
2. To refer to other water issues getting worse in the future, whereby an increasing number of even developed countries are heading towards higher rates of water stress unless they address these issues (much like Perth in Western Australia has done) – and, this of course has the potential for worsening consequences.
2. Hannah Ritchie and Max Roser (2018) – “Water Access, Resources & Sanitation”. Published online at OurWorldInData.org. Retrieved from: ‘https://ourworldindata.org/water-access-resources-sanitation’ [Online Resource]
18. Downloads/642-progress-on-level-of-water-stress-2018.pdf, ‘Progress On Level Of Water Stress’ (from unwater.org)