Groundwater Depletion

This section looks at a groundwater definition and a groundwater depletion definition, causes of groundwater depletion, effects of groundwater depletionsolutions to groundwater depletion and groundwater facts. The latest groundwater news is included at the foot of the page.

Ground water definition: groundwater is any freshwater that lies beneath the surface of the Earth. Groundwater depletion definition: groundwater pressures that remove more water than contribute and can be caused by natural and man-made processes. Groundwater accounts for around 30% of all freshwater. Fresh water is characterised by having low concentrations of dissolved salts and occurs above ground in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, rivers, lakes and streams and underground in aquifers and streams filling in the porous spaces between soil,sand and rocks.

Causes of groundwater depletion

Nature goes through a unique process to provide us with groundwater. The surface water that we can see is heated by the Sun and goes into the atmosphere as evaporation.

 

Water vapour then creates precipitation, water that falls from the sky as rain and snow. Once water falls from sky and onto the ground, it is absorbed into the Earth and is then stored as groundwater in aquifers.

Groundwater depletion background

Credit: National Geographic, groundwater is the water that seeps into the earth and is stored in aquifers—areas of soil, sand, and rock that are capable of holding liquid.

 

The water sits in between particles or in cracks and fissures. These saturated underground areas—some replenished by rain and snow, others not—can be found close to the Earth’s surface or hundreds of feet underground.

 

Threats to this underground source increase as population and development accelerate. Agricultural and urban runoff tainted with chemical pesticides and fertilisers seeps into groundwater sources but the biggest threat is simply withdrawing too much of this limited resource.

 

The overpumping of groundwater is causing water tables to fall across large areas of northern China, India, Pakistan, Iran, the Middle East, Mexico, and the western United States.

Causes of groundwater depletion: overuse

Credit: www.conserve-energy-future.com

 

Groundwater depletion most commonly occurs because of the frequent pumping of water from the ground.

 

We pump the water more quickly than it can renew itself, leading to a dangerous shortage in the groundwater supply.

 

As a growing world with a population that continues to rise, the more we pump water from the ground at a rapid rate, the more difficult it is for the groundwater to provide us with the amount of water that we need.

 

We continuously pump groundwater from aquifers and it does not have enough time to replenish itself. Water flows freely through the saturated rocks known as aquifers. There are large and small aquifers, and they are the underground water reserves that absorb water and hold it, enabling us to pump it for use.

Causes of groundwater depletion: agricultural needs

Credit: www.conserve-energy-future.com.

 

The amount of water that aquifers hold is impressive and can provide us with billions of gallons of water per day.

 

However, whilst usage happens on a constant basis, replenishment often takes much longer to achieve.

 

Agricultural needs require a large amount of groundwater - a steady supply of water to meet crop and livestock requirements, linking food security directly to water security. Agriculture is the largest consumer of freshwater resources in the world - In the U.S. about 65% of groundwater is used for agricultural irrigation.

 

It’s frightening to think that there isn’t very much groundwater left when you consider how much water we use on a daily basis to support our population of billions and our personal lifestyles.

 

The availability of groundwater is steadily declining.

Causes of groundwater depletion: pollution

Credit: www.groundwater.org.

 

Groundwater contamination occurs when man-made products such as gas, oil, road salts and chemicals get into the groundwater and cause it to become unsafe and unfit for human use.

 

Materials from the land's surface can move through the soil and end up in the groundwater.

 

For example, pesticides and fertilisers can find their way into groundwater supplies over time.

 

Road salt, toxic substances from mining sites, and used motor oil also may seep into groundwater.

 

In addition, it is possible for untreated waste from septic tanks and toxic chemicals from underground storage tanks and leaky landfills to contaminate groundwater.

 

Atmospheric contaminants in the air and from aerosols have an impact on groundwater availability through the constant actions of the water cycle.

Effects of groundwater depletion

As the world’s largest distributed store of fresh water, ground water plays a central part in sustaining ecosystems and enabling humans to improve resilience to climate variability and change. The strategic importance of ground water for global water and food security will undoubtably intensify in future due to rising global temperatures and population growth.

Groundwater depletion and climate change

Under a warming atmosphere, precipitation rates are predicted to increase, particularly in the tropics. Projected shifts in the timing of rainfall itself (e.g. changes to seasonal patterns) will result in more variable river discharge and soil moisture.

 

River dishcarge changes will impact on in-year freshwater shortages and the risk of flooding whereas soil moisture changes threaten food security through reduced crop yields.

 

Projected changes in the geographic distribution of average rainfall are substantial but remain highly uncertain for most of the world. Many current reports point to inadequacy of modelling techniques in not being able to draw firm predictions of future impact.

 

Strategies to adapt to more variable freshwater resources will, in many environments, increase dependence upon groundwater. Few climate impact models consider how climate variability and change affect groundwater recharge and the sustainable development of groundwater despite its central role in enabling adaptation in domestic and agricultural water sectors.

Groundwater depletion environmental effects

The following are common effects:

 

Land subsidence - the collapse of land from lack of structural support (from the water that is being depleted). 


Reduction of water volume in streams, lakes and wetland environments. Plants and animals that depend on streams and lakes for food, water and habitat are adversely affected - reducing biodiversity.

 

Deteriorating water quality.


Crop production decrease from lack of water availability (40% of global food production relies on groundwater).


Groundwater depletion interrupts the 'natural' water cycle putting disproportionately more water into the sea.

Groundwater depletion socio-economic effects

Water security and food security

Many countries are overpumping aquifers as they struggle to satisfy their growing water needs, including each of the big three grain producers— China, India, and the United States. These three, along with a number of other countries where water tables are falling, are home to more than half the world’s people.

 

Nearly half of our food comes from the warm, dry parts of the planet, where excessive groundwater pumping to irrigate crops is rapidly shrinking the porous underground reservoirs called aquifers.

 

Vast swaths of India, Pakistan, southern Europe, and the western United States could face depleted aquifers by mid-century, a recent study finds—taking a bite out of the food supply and leaving as many as 1.8 billion people without access to this crucial source of fresh water.

 

Computer simulation models predicted that California’s agricultural powerhouses—the Central Valley, Tulare Basin, and southern San Joaquin Valley, which produce a plentiful portion of the nation’s food—could run out of accessible groundwater as early as the 2030s. India’s Upper Ganges Basin and southern Spain and Italy could be used up between 2040 and 2060. And the southern part of the Ogallala aquifer under Kansas, Oklahoma, Texas, and New Mexico could be depleted between 2050 and 2070. 

 

Farming has mushroomed across arid regions like these in the past half century. With scarce rains and few rivers and lakes, they depend on water pumped up from underground. Since 1960, excessive pumping has already used up enough groundwater worldwide to nearly fill Lake Michigan. With climate change and population growth, future groundwater use will soar. 

 

A 2015 study based on satellite observations showed that most of the world’s largest aquifers—21 out of 37—are being drained faster than they can refill. “A number of studies point to the overuse of groundwater and the tremendous risk that our water and food security are under,” says water scientist Jay Famiglietti of the NASA Jet Propulsion Laboratory, who led the satellite study. “The problem is, we don’t know how much groundwater is left.”

 

The cost of water to the consumer rises. This is due to the water table lowering so more energy is needed to pump further down. Once the depth of extractable water falls below 300 feet, it becomes uneconomical for most companies to recover.

Crop Irrigation Is Closely Tied to Groundwater Depletion Around the World: NASA Goddard video   

Solutions to groundwater depletion

Government actions to conserve groundwater 

While groundwater use has increased manyfold, with major socioeconomic benefits, little attention has been given to its governance and to resource conservation and protection.

 

Given the major concern about the future of groundwater, the Global Environment Facility (GEF) and the UN Food & Agriculture Organization (UNFAO), together with the UNESCO International Hydrological Programme (IHP), the International Association of Hydrogeologists (IAH) and the World Bank, initiated a major program which ran between 2011 and 2016 to review and strengthen groundwater governance.through a shared Vision and a Framework for Action.

 

The objective of the project  was to embed a process of improved groundwater governance to halt the current trend of resource depletion and degradation and lead to positive environmental, social and economic outcomes. 

 

The project team worked together with groundwater stakeholders worldwide in a series of five regional consultations. 

 

The outputs generated resulted in a Shared Vision and a Framework for Action.

 

Thematic areas addressed were:

No.1 – Trends in groundwater pollution; trends in loss of groundwater quality and related aquifers services. 
 
No.2 - Conjunctive Use and Management of Groundwater and Surface Water. 


No.3 – Urban-rural tensions; opportunities for co-management. 


No.4 - Management of aquifer recharge / discharge processes and aquifer equilibrium states.

 

No.5 - Groundwater Policy and Governance.

 

No.6 – Legal framework for sustainable groundwater governance. 


No.7 – Trends in local groundwater management institutions / user partnerships. 


No.8 - Social adoption of groundwater pumping technology and the development of groundwater cultures: governance at the point of abstraction. 

 

No.9 – Macro-economic trends that influence demand for groundwater and related aquifer services. 


No.10 - Governance of the subsurface and groundwater frontier. 


No.11 - Managing the Invisible - Understanding and Improving Groundwater Governance. 


No.12 - Groundwater and climate change adaptation. 

Personal actions to conserve groundwater

Top 10 ways to protect and conserve groundwater. Credit: www.groundwater.org.

 

Go native

Use native plants in your landscape. They look great, and don't need much water or fertiliser. Also choose grass varieties for your lawn that are adapted for your region's climate, reducing the need for extensive watering or chemical applications.

 

Reduce chemical use

Use fewer chemicals around your home and garden, and make sure to dispose of them properly - don't dump them on the ground!

 

Manage waste

Properly dispose of potentially toxic substances like unused chemicals, pharmaceuticals, paint, motor oil, and other substances. Many communities hold household hazardous waste collections or sites - contact your local health department to find one near you.

 

Don't let it run

Shut off the water when you brush your teeth or shaving, and don't let it run while waiting for it to get cold. Keep a pitcher of cold water in the fridge instead.

 

Fix the drip

Check all the taps, fixtures and toilets in your home for leaks and fix them right away, or install water conserving models.

 

Wash smarter

Limit yourself to just a five minute shower, and challenge your family members to do the same! Also, make sure to only run full loads in the dish and clothes washer.

 

Water wisely

Water the lawn and plants during the coolest parts of the day and only when they truly need it. Make sure you, your family, and your neighbours obey any watering restrictions during dry periods.

 

Reduce, reuse, and recycle

Reduce the amount of "stuff" you use and reuse what you can. Recycle paper, plastic, cardboard, glass, aluminum and other materials.

 

Natural alternatives

Use all natural/nontoxic household cleaners whenever possible. Materials such as lemon juice, baking soda, and vinegar make great cleaning products, are inexpensive, and environmentally-friendly.

 

Education

Get involved in water education! Learn more about groundwater and share your knowledge with others.

Groundwater news

For the latest groundwater news stories and other environmental news, check out our news page

 

Water security news published on www.eco-business.com.

 

Groundwater articles published on www.theconversation.com.

 

Water security news published on www.watersecuritynetwork.org.

 

Water security news published on www.unesco.org.

 

Water crisis articles on www.nationalgeographic.com.

 

 

 

 

 

 

Groundwater facts

Groundwater accounts for 30% of all freshwater, freshwater accounts for only 3% of all water on Earth

Only 3% of the Earth's water is fresh water. Most of it in icecaps and glaciers (69%) and groundwater (30%), while all lakes, rivers and swamps combined only account for a small fraction (0.3%) of the Earth's total freshwater reserves.

Groundwater depletion raises sea-levels by around 1mm per year

Various studies have estimated the impact of groundwater depletion on global sea levels. Dutch scientists claim groundwater depletion adds about 25 percent to projected rates of sea-level rise, making it the largest contributor from land to sea-level rise other than the melting of the Greenland and Antarctic ice sheets.

23 million cubic kilometers of groundwater held globally

If this volume is hard to visualise, imagine the Earth's entire land surface covered in a layer some 180m deep. Source: www.nature.com.

80% of the world's population live in areas with threats to water security and 50% of the world's population relies on groundwater for drinking water

According to a 2010 Nature report, about 80% of the world's population live in areas with threats to water security. 

40% of global food production now relies on irrigation with groundwater

Since 1960, groundwater extraction has increased by over 300%

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