The human body, in average, is made of 50-65 percent of water. Babies have the highest percentage of water; newborns are 78 percent water. Every day, every person needs access to water for drinking, cooking and personal hygiene. Water is essential for sanitation facilities that do not compromise health or dignity. The World Health Organization recommends 7.5 liters per capita per day will meet the requirements of most people under most conditions. A higher quantity of about 20 liters per capita per day will take care of basic hygiene needs and basic food hygiene. Despite impressive gains made over the last decade, 748 million people do not have access to an improved source of drinking water and 2.5 billion do not use an improved sanitation facility. Investments in water and sanitation services result in substantial economic gains. The return on investment of attaining universal access to improved sanitation has been estimated at 5.5 to 1, whereas for universal access of improved drinking-water sources the ration is estimated to be 2 to 1. To cover every person worldwide with safe water and sanitation is estimated to cost US$ 107 billion a year over a five-year period. The reality is that water is not confined to political borders. For instance, an estimated 148 states have international basins within their territory and 21 countries lie entirely within them. There are 276 showing transboundary river basins in the world and the configuration of these transboundary river basins includes:
- 64 in Africa;
- 60 in Asia;
- 68 in Europe;
- 46 in North America; and
- 38 in South America.
A transboundary river is a river that crosses at least one political border, either a border within a nation or an international boundary. Furthermore, 185 out of the 276 transboundary river basins, about two-thirds, are shared by two countries. 256 out of 276 are shared by 2, 3 or 4 countries (92.7 Percent), and 20 out of 276 are shared by 5 or more countries (7.2 Percent), the maximum being 18 countries sharing a same transboundary river basin. 46 percent of the globe’s (terrestrial) surface is covered by transboundary river basins. 148 countries include territory within one or more transboundary river basins. 39 countries have more than 90 percent of their territory within one or more transboundary river basins, and 21 lie entirely within one or more of these watersheds. Russian Federation shares 30 transboundary river basins with riparian countries, Chile and United States 19, Argentina and China 18, Canada 15, Guinea 14, Guatemala 13, and France 10. Africa has about one-third of the world’s major international water basins – basins larger than 100,000 km2. Virtually all sub-Saharan African countries, and Egypt, share at least one international water basin. Depending on how they are counted, there are between 63 and 80 Transboundary River and lake basins on the African continent. Rich nations are tending to maintain or increase their consumption of natural resources, but are exporting their footprints to producer, and typically, poorer, nations. European and North American populations consume a considerable amount of virtual water embedded in imported food and products. Each person in North America and Europe (excluding former Soviet Union countries) consumes at least 3 m3 per day of virtual water in imported food, compared to 1.4 m3 per day in Asia and 1.1 m3 per day in Africa. Demographic projections suggest that world population will increase from 7.0 billion by a third -to 9.3 billion- by 2050. Most of this increase will occur in developing countries. Currently food production (Agriculture) in order to feed 7 billion people in the world consumes 70 percent of the available water in the world.
According to the World Water Development report (2014), the industrial and domestic sectors account for the remaining 20 percent and 10 percent, respectively, although these figures vary considerably across countries. In most of the world’s least developed countries, agriculture accounts for more than 90 percent of water withdrawals. Rainfed agriculture is the predominant agricultural production system around the world, and its current productivity is, on average, little more than 1/2 the potential obtainable under optimal agricultural management. Without improved efficiencies, agricultural water consumption is expected to increase globally by about 20 percent and 60 percent more food needed by 2050. Additionally, just to keep in mind that:
- Freshwater withdrawals have tripled over the last 50 years. Demand for freshwater is increasing by 64 billion cubic meters a year (1 cubic meter = 1,000 liters);
- Changes in lifestyles and eating habits in recent years are requiring more water consumption per capita;
- The production of biofuels has also increased sharply in recent years, with significant impact on water demand. Between 1,000 and 4,000 litres of water are needed to produce a single litre of biofuel; and
Energy demand is also accelerating, with corresponding implications for water demand. Various estimates indicate that, based on business as usual, ~3.5 planets Earth would be needed to sustain a global population achieving the current lifestyle of the average European or North American. Global population growth projections combined with changing diets, result in a predicted increase in food demand of 70 percent by 2050. Another way to look at this challenge, with expected increases in population, by 2030, food demand is predicted to increase by 50 percent (70 percent by 2050), while energy demand from hydropower and other renewable energy resources will rise by 60 percent. These issues are interconnected – increasing agricultural output, for example, will substantially increase both water and energy consumption, leading to increased competition for water between water-using sectors. The justification for high estimates for agriculture demand could be associated with the economic growth and individual wealth which are shifting diets from predominantly starch-based to meat and dairy, which require more water. Producing 1 kg of rice, for example, requires ~3,500 L of water, 1 kg of beef ~15,000 L, and a cup of coffee ~140 L. This dietary shift is the greatest to impact on water consumption over the past 30 years, and is likely to continue well into the middle of the twenty-first century. The Intergovernmental Panel on Climate Change (IPCC) predicts with high confidence that water stress will increase in central and southern Europe, and that by the 2070s, the number of people affected will rise from 28 million to 44 million. Summer flows are likely to drop by up to 80 percent in southern Europe and some parts of central and Eastern Europe. Europe’s hydropower potential is expected to drop by an average of 6 percent, but rise by 20–50 percent around the Mediterranean by 2070. Here is another reality. Fresh water makes up about 2.5 percent of all the water on earth. Meanwhile, humans have already reached “peak water,” according to Bank of America. That means we’re at the limit, or approaching the limit, of environmental, physical and economic demands on the renewable freshwater supply. Consequently, in order to overcome the shortage of fresh water, countries like India, China, and USA started pumping groundwater recurrently and repetitively. Groundwater is the largest source of usable, fresh water in the world. In many parts of the world, especially where surface water supplies are not available, domestic, agricultural, and industrial water needs can only be met by using the water beneath the ground. The US Geological Survey compares the water stored in the ground to money kept in a bank account. If the money is withdrawn at a faster rate than new money is deposited, there will eventually be account-supply problems (Overdraft). Pumping water out of the ground at a faster rate than it is replenished over the long-term will cause similar problems. According to the National Groundwater Association:
- 99 percent of all water on earth is unusable for humans;
- Of all water on earth, only 1 percent is available for humans use;
- Of the usable 1 percent: 99 percent comes from groundwater which is a combination of:
- 0.86 percent from lakes; and
- 0.22 percent from rivers.
- Of all fresh water on earth:
- 68.7 percent is icecaps and glaciers;
- 30.0 percent is groundwater;
- 0.3 percent is surface water; and
- 0.9 percent is other.
Groundwater is a source of recharge for lakes, rivers, and wetlands. Groundwater can be found almost everywhere. The water table may be deep or shallow; and may rise or fall depending on many factors. Heavy rains or melting snow may cause the water table to rise, or heavy pumping of groundwater supplies may cause the water table to fall. Groundwater supplies are replenished, or recharged, by rain and snow melt that seeps down into the cracks and crevices beneath the land’s surface. In some areas of the world, people face serious water shortages because groundwater is used faster than it is naturally replenished. In other areas groundwater is polluted by human activities. As can be seen from the graph presented below that water in aquifers is brought to the surface naturally through a spring or can be discharged into lakes and streams. Groundwater can also be extracted through a well drilled into the aquifer. A well is a pipe in the ground that fills with groundwater. This water can be brought to the surface by a pump. Shallow wells may go dry if the water table falls below the bottom of the well. Some wells, called artesian wells, do not need a pump because of natural pressures that force the water up and out of the well. Although groundwater exists everywhere under the ground, some parts of the saturated zone contain more water than others. An aquifer is an underground formation of permeable rock or loose material which can produce useful quantities of water when tapped by a well. Aquifers come in all sizes and their origin and composition is varied. They may be small, only a few hectares in area, or very large, underlying thousands of square kilometres of the earth’s surface. They may be only a few meters thick, or they may measure hundreds of meters from top to bottom. Furthermore, groundwater may be used as a source of heat. Ground source heat pumps are receiving increased attention as energy efficient commercial and residential heating/cooling systems. Although initial costs are higher than air source systems — due to the additional costs of the underground installations — the much greater energy efficiency of ground source systems makes them increasingly attractive. Groundwater can be defined as the water found underground in the cracks and spaces in soil, sand and rock. It is stored in and moves slowly through geologic formations of soil, sand and rocks called aquifers. Here are some facts about groundwater:
- Groundwater is the world’s most extracted raw material with withdrawal rates currently in the estimated range of 982 km3/year;
- About 60 percent of groundwater withdrawn worldwide is used for agriculture; the rest is almost equally divided between the domestic and industrial sectors;
- In many nations, more than half of the groundwater withdrawn is for domestic water supplies and globally it provides 25 percent to 40 percent of the world’s drinking water; and
- Globally, about 38 percent of irrigated lands are equipped for irrigation with groundwater.
The 15 nations with the largest estimated annual 1: Irrigation %, 2: Domestic %, and 3: Industry % Groundwater extractions (2010)5 are:
|Country||Population2010(in Thousand)||Estimated Groundwater Extraction 2010 (Km3/YR)||Groundwater Extraction|
|Breakdown by Sector|
|National Groundwater Association|
Here is a quick analysis on the graph presented above:
- 15 nations included on the graph, represent a total population of 4.15 billion in 2010;
- These nations covered a total of 769.91 Km3/year estimated groundwater extraction in 2010 with the following classification:
- Irrigation 60 Percent;
- Domestic 29 Percent; and
- Industry 11 Percent.
- The top three countries, India, China, and USA, covered a total of 474.65 Km3/year estimated groundwater extraction in 2010 which represents 61.65 percent of the total estimated groundwater extraction for all 15 nations.
Even though the data presented in the graph only elucidated the magnitude of groundwater which was propelled by each country in 2010 but it allows us to imagine about the potential increase in the use of groundwater in those countries. For instance, as far as the USA is concerned, California is now in its fourth year of a record-breaking drought. This past winter was the hottest and driest since the state started keeping written records. And yet, pay a visit to California’s Central Valley and out of that parched land you’ll see acre upon acre of corn, almond trees, pomegranates, tomatoes, grapes. And what makes them all possible: water. Where do you get water in a drought? You take it out of the savings account: groundwater. Farmers in California are saying that “we have no choice but to keep drilling more wells and chase the water down.” At his office on the leafy campus of California State University, Sacramento, hydrogeologist Tim Horner said, “In California, we are pumping out groundwater faster than it can recharge.” Horner chairs his school’s geology department and many of his former students have flocked to the Central Valley to search for water and advise drilling operations. But the science is hampered by the Golden State’s antiquated regulatory structure, Horner said. California is the only state Horner is aware of that does not require water well logs to be made available to scientists and regulators. In dry Texas, in contrast, well data must be posted online so that officials can track the status of aquifers. Even worse, “in California we don’t regulate our pumping at all,” said Horner. “There’s nothing that says someone can’t pump a well until it’s dry.” A July 31 report from Stanford University’s Water in the West program pointed out that in normal years, groundwater provides about 40 percent of the water California uses. But during drought, that number jumps to 60 percent. “Using groundwater to supplement California’s water supply has allowed farmers and communities in California to limp through the current drought, but at the cost of dramatically drawing down the aquifers,” the report warns. According to Horner, not only does emptying aquifers pose a risk for a water-scarce future, but it also can decrease the amount of water that may be available to recharge springs and streams and nourish ecosystems. And as water is removed, it can cause soil to collapse. Not only can this permanently decrease the amount of water that an aquifer can hold, but it can also lead to disruptions on the surface through land subsidence. In some places in the Central Valley, land has dropped by a foot. This has damaged roads, pipes, and other infrastructure and has caused some canals to stop working. California pumps 10.7 billion gallons per day of groundwater for all purposes, a third more as much than the second-ranked state — Texas (8.02 bgd). Looking at the bigger picture of the use of groundwater, the United States uses 79.6 billion gallons per day of fresh groundwater for public supply, private supply, irrigation, livestock, manufacturing, mining, thermoelectric power, and other purposes. Approximately 500,000 new residential wells are constructed annually, according to NGWA estimates. The construction of these vitally needed water supply systems involves the use of more than 18,460 drilling machines by an estimated 8,085 groundwater contracting firms. Here is a graph which illustrates the overall used of groundwater every day in the USA:
|Use of Groundwater in America Million Gallons Per Day (mgd)|
Unfortunately, people who are pumping groundwater extensively only to meet their need, they don’t realize the following the negative effects: Groundwater depletion is primarily caused by sustained groundwater pumping. Some of the negative effects of groundwater depletion:
- Lowering of the Water Table: Excessive pumping can lower the groundwater table, and cause wells to no longer be able to reach groundwater;
- Increased Costs: As the water table lowers, the water must be pumped farther to reach the surface, using more energy. In extreme cases, using such a well can be cost prohibitive;
- Reduced Surface Water Supplies: Groundwater and surface water are connected. When groundwater is overused, the lakes, streams, and rivers connected to groundwater can also have their supply diminished;
- Land Subsidence: Land subsidence occurs when there is a loss of support below ground. This is most often caused by human activities, mainly from the overuse of groundwater, when the soil collapses, compacts, and drops; and
- Water Quality Concerns: Excessive pumping in coastal areas can cause saltwater to move inland and upward, resulting in saltwater contamination of the water supply.
Here is an interesting angle to minimize the use of groundwater which was reported recently. Land grabbing is another increasingly common phenomenon. Saudi Arabia, one of the Middle East’s largest cereal growers, announced it would cut cereal production by 12 percent a year to reduce the unsustainable use of groundwater. To protect its water and food security, the Saudi government issued incentives to Saudi corporations to lease large tracts of land in Africa for agricultural production. By investing in Africa to produce its staple crops, Saudi Arabia is saving the equivalent of hundreds of millions of gallons of water per year and reducing the rate of depletion of its fossil aquifers.Nearly all Arab countries suffer from water scarcity. An estimated 66 percent of the Arab region’s available surface freshwater originates outside the region.Perhaps the only way to stop abusing groundwater is to find inventive ways of meeting human needs for water. Resources:
- UN Water – Humanity Needs Water;UN Water – Agriculture is the biggest water user;
- UNESCO – An Increasing Demand;
- National Groundwater Association – Facts about Groundwater;
- The Groundwater Foundation – The Basics;
- Environment Canada – Groundwater;
- National Groundwater Association – Facts about Global Groundwater Usage;
- The 60 Minutes – Water;
- National Geographic – California Drought Spurs Groundwater drilling Boom in Central Valley;
- Water in the West – Understanding California’s Groundwater;
- National Groundwater Association – Groundwater Facts; and
- The Groundwater Foundation – Potential Threats to Our Groundwater.