Water Stress Is Not Your Destiny
Water stress is just one dimension of water security. Like any challenge, its outlook depends on management. Even countries with relatively high water stress have effectively secured their water supplies through proper management.
Saudi Arabia, ranked #8 for water stress, prices water to incentivize conservation. Its new Qatrah program sets water conservation targets and aims to reduce water usage 43% within the next decade. Namibia, one of the most arid countries in the world, has been turning sewage water into drinking water for the past 50 years. And Australia nearly halved domestic water use to avert its own Day Zero moment during the Millennium Drought. The countrys water-trading scheme, the largest in the world, allows for smart allocation of water among users in the face of variable supplies.
Why Rank Water Stress in Countries and States?
Water does not follow boundaries set by humans–rivers run across countries, and a flood may only affect a few city blocks. For this reason, most water-related information is collected at a watershed or sub-watershed scale. Yet the policy decisions required to reverse water stress like setting withdrawal caps, encouraging wastewater treatment and establishing pricing schemes primarily take place at an administrative scale, such as at a country, state or provincial level.
Expansion Of Agricultural And Industrial Users
Scarcity as a result of consumption is caused primarily by the extensive use of water in agriculture/livestock breeding and industry. People in developed countries generally use about 10 times more water daily than those in developing countries. A large part of this is indirect use in water-intensive agricultural and industrial production processes of consumer goods, such as fruit, oilseed crops and cotton. Because many of these production chains have been globalized, a lot of water in developing countries is being used and polluted in order to produce goods destined for consumption in developed countries.
Many aquifers have been over-pumped and are not recharging quickly. Although the total fresh water supply is not used up, much has become polluted, salted, unsuitable or otherwise unavailable for drinking, industry and agriculture. To avoid a global water crisis, farmers will have to strive to increase productivity to meet growing demands for food, while industry and cities find ways to use water more efficiently.
Strategies To Increase Water Supply
Over 60% of the worlds landmass is filled with water. There is enough water for everyone. However, availability and supply vary from place to place. The difference in these areas is primarily due to the strategies of conserving water and increasing its amount. Some of these strategies require substantial monetary investment. Others are small-scale and are less expensive to manage, and a few plans are natural.
Strategies for increasing water supply can be grouped into these categories:
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Water Supply & Conservation
Disadvantages | ||
River, lakes and other natural bodies of water | Water is naturally available and it is easy to access it and distribute it to users. Dams and reservoirs can be build to further increase water storage. | In LEDCs these sources can become easily polluted and if water is not treated it can carry diseases such as cholera. |
Wells and bore holes | Water is naturally purified by filtration through bedrock and can exist in arid areas where there is limited surface water eg. Great Artesian Basin in Australia | Constructing wells costs money as does extracting the water through pumps. It is usually limited in quantity and can not sustain large populations or agriculture. |
Desalinisation plants | Supply is virtually unlimited | It is extremely expensive and uses a lot of energy |
Rainwater harvesting | Water is usually very pure and can be consumed with limited treatment | Rain is unpredictable and storage of water can be difficult. |
Water condensing |
The Earths Water Supply
Key Words
- Water Surplus: There is more fresh usable water that is needed for the needs of the area .
- Water Deficit: There is not enough fresh usable water to meed the needs of the area
In this Unit we will be examining the Fresh Water Supply.Using the graphs to examine where the Earth’s water supply is found and determine what percentage is usable for People and Agriculture and where it comes from. The distribution of the Earth’s Fresh water reserves | The distribution of the earths water supply |
Using the data in the table create a graph showing the percentage of water usage in the USA. | |
Uses of Water | Quantity in million of litres a day |
Public use |
Access to safe drinking water | Fresh water availability per person |
Whole class discus the factors that affect water shortages supply and demand |
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Example Bucket Water Budget
A simplified sample annual water budget of the South Okanagan at elevation is included below . In this case, the amounts of precipitation, evapotranspiration, surplus and storage are all expressed in millimetres . The size of the bucket, which represents the Water Holding Capacity of the soil, has been set to be 150 mm of storage available in the soil column.
Figure 9.2.WebWIMP. Source: G. Krezoski, CC-BY-NC-SA 4.0.
Month | |
118 | 12 |
In the winter months precipitation includes some rainfall but mostly snowfall. During this period, the bucket is filling up during a recharge phase, which is expressed in Table 9.1 as storage . Surplus water escapes via stream systems rapidly in the late spring, often causing flooding.
One should note that because of snowmelt occurring in the late spring, the South Okanagan especially at elevation is a bit more complex than Table 9.1 suggests. Since that snow already fell as precipitation earlier in the year, it is not accounted for in this simple soil-water balance exercise. In reality, the surplus in the spring is much higher due to the snowmelt.
Ex: Completing A Water Budget
A water budget can be useful for city planning and for irrigations needs. Indeed, after examining water budgets, city planners and engineers in the Okanagan built reservoirs to capture spring runoff for agricultural and city needs.
In this exercise you will complete a water budget local to your area.
Water Budget Location: _______________________________________________
Once complete, answer the following questions in 2-3 sentences. Remember, this is individual work.
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Water Resources Supply And Demand
Key WordsWater quality – Quality can be measured in terms of the chemical, physical, and biological content of water. The most common standards used to assess water quality relate to health of ecosystems, safety of human contact and drinking water.Water security – The reliable availability of an acceptable quantity and quality of water for health, livelihoods and production.Water stress – Water stress occurs when the demand for water exceeds the available amount during a certain period or when poor quality restricts its use.Water surplus – This exists where water supply is greater than demand.Water insecurity -When water availability is not enough to ensure the population of an area enjoys good health, livelihood and earnings. This can be caused by water insufficiency or poor water quality
Water is an essential resource for human survival, but its distribution and availability vary within countries and across the planet. Only 2.5% of the water on the Earth is freshwater, the rest is found in the oceans. Unfortunately, a lot of the freshwater is locked up in ice caps and glaciers so is unavailable for human use. This poses problems for people as freshwater is a scarce resource.
Water surplus and deficit :
Reservoirs – Humans can create artificial lakes by buildings big concrete walls known as dams across rivers to prevent them flowing. We can then treat the water and consume it. Kielder water in Northumberland is a good example of this.
Case Study: Drought In California
California is a coastal state in western USA. It has deserts to the east, but there is usually plenty of rainfall to provide water along the coast.
California has experienced drought since 2011. Irrigated crops use a lot of the freshwater supplies in the region. Rising temperatures, falling rainfall levels and a growing population are also contributing to the problem.
The drought has lowered groundwater levels. This can cause lots of problems, such as:
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A Implementation Of The Model
1) Flowchart of simulation
Fundamentally, the model equations are based on micrometeorology, and are used on short timescale . However, some meteorological factors such as S and P are monthly total values, which need to be interpolated into diurnal values. In the present study, we simply used monthly total values divided by the number of days in each month and obtained diurnal values. On the other hand, the meteorological measurements of 107 stations were interpolated into each 0.25° lat × 0.25° long grid cell with the distance weight least squares methods, and the land surface parameters in each grid cell were derived from various maps of China mentioned above. Figure 4 shows the flowchart of data processing and simulation.
2) Distribution of estimated values
3) Seasonal changes in estimated values
Seasonal variations in E0, Ea, and WDI were very clear in the study area. The averages of 107 grid cells over the whole plateau are shown in Fig. 6a, in which E0 and Ea had the lowest values in January and the highest values in June, whereas WDI had the lowest value in July and highest value in December.
To analyze regional differences in seasonal changes, the averages of E0, Ea, and WDI in four subzones were computed. The results showed that the characteristics of seasonal variation were similar in the four subzones but their amplitudes were different according to the zone. One interesting characteristic is that regional differences are small in winter, but large in summer .
Middle East And North Africa Is The Most Water
Twelve out of the 17 most water-stressed countries are in the Middle East and North Africa . The region is hot and dry, so water supply is low to begin with, but growing demands have pushed countries further into extreme stress. Climate change is set to complicate matters further: The World Bank found that this region has the greatest expected economic losses from climate-related water scarcity, estimated at 6-14% of GDP by 2050.
Yet there are untapped opportunities to boost water security in MENA. About 82% of the regions wastewater is not reused harnessing this resource would generate a new source of clean water. Leaders in treatment and reuse are already emerging: Oman, ranked #16 on our list of water-stressed countries, treats 100% of its collected wastewater and reuses 78% of it. About 84% of all wastewater collected in Gulf Cooperation Council countries is treated to safe levels, but only 44% goes on to be reused.
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The Changing Demand For Water
In the past, people used far less water. Water use has increased as more people wash cars, take longer showers and water their gardens. People are now wealthier and have luxury goods such as washing machines and dishwashers which also increase water use.
Only a proportion of the UK’s total water use comes from within the country. Imported products, like food and cotton, use up water resources in the countries where they are grown. The UK’s water footprint is a measure of the total water used both within the UK and in other countries through imported products.
The UK government has also considered creating a national water grid. This would work in a similar way to the national electricity grid, but it would be used to link up the country’s water supplies.
What Do You Mean By Water Conflict
Water conflict refers to local, national, or opposing international interests of different states, countries, or even groups of public and private users over the use and management of water resources. The leading cause of water conflicts is water scarcity or water stress. Which are often due to low rainfall, overpopulation, industrialization, climate change, water pollution, and other non-water related conflicts due to historical tensions?
References
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The Relationship Between These Terms
Water scarcity is an indicator of a problem with water availability where there is a high ratio of water consumption to water resources in a given area. Water availability, water quality, and water accessibility are the three components that are comprised by water stress. As such, water scarcity and additional indicators can be used to assess water stress. Scarcity and stress both directly inform ones understanding of risks due to basin conditions. Companies and organizations cannot gain robust insight into water risk unless they have a firm understanding of the various components of water stress , as well as governance and other non-water-related-stress factors.
Student Activity: Processes: Defining Water Scarcity
Read the following text and complete the gap-fill on your worksheetWater stress: When the demand for water exceeds the supply of water and shortages exist.
Physical Water Scarcity: When the supply of rainfall is lower than the demand of water.Economic Water Scarcity: When water supplies exist, but the local population can not access them because of pollution, lack of technology, etc.
Water scarcity is both a natural and a human-made phenomenon. There is enough freshwater on the planet for the human population but it is distributed unevenly and too much of it is wasted, polluted and unsustainably managed.
Hydrologists typically assess scarcity by looking at the population-water equation. An area is experiencing water stress when annual water supplies drop below 1,700 m3 per person. When annual water supplies drop below 1,000 m3 per person, the population faces water scarcity, and below 500 cubic metres “absolute scarcity”
Student Activity – Water in the Anthropocene – Processes and Spatial Interactions
Watch the folllowing video and make notes on the ways humans are impacting access to water
Student Activity _Spatial Interactions and Place_ The Causes of Water scarcity
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Water Scarcity _Spatial Interactions_FAO Video on Water Scarcity
Watch the following video and answer the question on your worksheet
Student Activity_Processes_ Water Scarcity Card Sort
Work with the card sort to
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Causes And Contributing Factors
Around fifty years ago, the common perception was that water was an infinite resource. At that time, there were fewer than half the current number of people on the planet. People were not as wealthy as today, consumed fewer calories and ate less meat, so less water was needed to produce their food. They required a third of the volume of water we presently take from rivers. Today, the competition for water resources is much more intense. This is because there are now seven billion people on the planet, their consumption of water-thirsty meat is rising, and there is increasing competition for water from industry, urbanization biofuel crops, and water reliant food items. In the future, even more water will be needed to produce food because the Earth’s population is forecast to rise to 9 billion by 2050.
In 60% of European cities with more than 100,000 people, groundwater is being used at a faster rate than it can be replenished.
Over-exploitation of groundwater
Infrastructure Monitoring And Repairs
Another key in the water savings puzzle is the ongoing need worldwide for infrastructure monitoring and repair to prevent loss of water through delivery systems. These small amounts become increasingly larger over time. Monitoring aging infrastructure and creating new technologies such as wireless smart valves and pipe defect and leak-detection sensing devices are helping, but they must be used along with water policies such as routine reporting and repair plans.
How big is the problem? According to a 2013 report from the Center for Neighborhood Technology, in the U.S., an estimated 2.1 trillion gallons per year about 16% of the water used in the nation daily is lost through outdated and leaky infrastructure. In Europe, the estimated value of water lost through leaky infrastructure is roughly 80 billion euros per year, according to the Community Research and Development Information Service.
Contributing to the problem is inadequate funding for infrastructure repair or replacement. Even in the U.S., investments of more than $1 trillion are needed to repair and expand the nations aging drinking water infrastructure, according to a 2013 American Water Works Association report. Estimates for repairing and upgrading wastewater treatment systems throughout the nation were similar.
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