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AC Atienza, Brendan Bate, Shannon Smithwick, Steff Stephansson, Kaleigh Watson, Andrew Wilson.
Groundwater is a vital natural resource which, although mostly out of sight, sustains life on Earth. Amongst other things, groundwater provides drinking water, and is widely used by agriculture and industry. In fact, in Canada, about 30% of the population depends on groundwater for domestic use [1]. When looking at the world’s population, that number rises to an estimated 50% [2].
However, extracting too much water from the ground can lead to serious consequences for both communities and ecosystems.
In this article, we explore some of the challenges which surround groundwater use and will look at ways to manage those complexities.
First of all, let’s define groundwater. For the purposes of this discussion, groundwater is subsurface (i.e. underground) water which originates from rainfall or snowmelt that penetrates the layer of soil just below the surface. For us to be able to access it, the groundwater must be in an aquifer.
There is a lot of groundwater– some sources estimate there is a thousand times more groundwater than surface water such as lakes and rivers [3]. However, much of it cannot easily be accessed or is contaminated with salt or other chemicals (e.g. silt, road salt, pesticides, metals) which makes it impossible or impractical for us and ecosystems to use [4].
There is a saying that “nature abhors a vacuum” which basically means that where there is a gap, something will fill it – think of water being poured into a glass holding ice-cubes and filling up the gaps between the ice-cubes. When groundwater is extracted from an aquifer, things happen such as the water table dropping. which may cause more water to move in through surface water recharge or from nearby aquifers or the sea. Or, the ground that holds the water may settle and become more compact. If settling happens, the aquifer may no longer hold as much water as it used to.
A lot depends on how quickly that water is extracted. Time is important to the issue in several different ways:
In many parts of the world, groundwater is being extracted far faster than it can be replaced through natural recharge. In effect, the water currently being used is water which has accumulated in previous years, centuries or millennia depending on how quickly the recharge happens in that area. The effect of this over-extraction is that the amount of groundwater available in that area is reduced and the water table drops further below the surface. The ground level may also drop because of the water extraction. Well known areas of significant storage depletion include the California Central Valley [5] (causing the surface of the earth in some locations to settle as much as 8.5 metres [6]) and the Arabian Aquifer System (potentially running dry in ~60-90 years) [7]. It’s estimated that:
Land subsidence is a phenomenon where the land surface sinks. This often is a result of pore spaces in aquifers collapsing due to reduced water pressure caused when water is removed. This allows the ground above and, in the aquifer, to compact and settle.
This subsidence damages infrastructure such as houses, roads, buildings, bridges and pipelines. This may directly threaten community safety (e.g. Jakarta [9]) and economic development but can also require expensive repair work. Also, land subsidence alters surface drainage patterns which may worsen flooding in low-lying areas and so threaten communities and disrupt ecosystems.
It is currently estimated that almost 2 billion people are at risk from the ground level subsiding (i.e. dropping) more than 5 mm per year [10] although not all of that subsidence is related to groundwater extraction.
In the natural state groundwater levels or the water table fluctuate between drawdown through extraction and recharge from rainfall and other naturally occurring inflow. When extraction and recharge are not in balance, problems arise. If there is too high a water table flooding may occur in low-lying areas including in home basements and underground parking spaces. As the water table drops, wetlands, rivers, wells and springs dry up, posing a threat to communities reliant on groundwater for drinking and irrigation. This depletion exacerbates water scarcity, particularly in arid and semi-arid regions, where groundwater may be a vital lifeline during droughts.
Agricultural communities reliant on groundwater for irrigation face reduced crop yields and income instability due to declining water availability and crop quality. As water becomes scarcer and more expensive, communities, particularly those in rural and impoverished areas, may struggle to meet their basic needs. This can lead to increased poverty, human migration, changed land use patterns and reduced quality of life especially where water quality is also being compromised. As water stress increases, tension over water resources can arise, both within and between communities, potentially leading to social unrest and instability [11] [12].
Industries dependent on groundwater (e.g. mining, oil and gas, power generation, apparel) [13] for core processes may face production constraints, leading to job losses and economic downturns. Socioeconomic disparities may deepen as marginalized communities bear the brunt of water scarcity and environmental degradation.
Groundwater plays a crucial role in sustaining ecosystems, particularly in arid and semi-arid regions where surface water may be scarce. Aquifers feed springs, rivers, and wetlands, supporting a diverse range of plant and animal life across landscapes ranging from mountain valleys, oceans and deserts [14].
Excessive groundwater extraction can reduce the flow of water to these ecosystems, leading to their degradation and potential collapse. For example, reduced water flow can affect the migration, spawning and feeding patterns of fish and other aquatic species, leading to declines in biodiversity and a decrease in climate resilience. Wetlands, which provide critical habitat for numerous species, can dry up resulting in the loss of biodiversity and the ecosystem services they provide, such as water purification, flood control, and carbon sequestration.
Intensive groundwater extraction increases the risk of groundwater contamination, as pollutants from agricultural runoff, industrial activities, and improper waste disposal infiltrate aquifers more rapidly in depleted systems. Contaminants such as nitrates, pesticides, and heavy metals pose potential health risks to communities reliant on groundwater for drinking water, leading to waterborne diseases and long-term health issues. Further, contaminated groundwater can have cascading effects on ecosystems, affecting aquatic species and soil fertility.
In coastal areas, excess groundwater extraction can result in the inland movement of the freshwater-saltwater interface leading to seawater intrusions into the groundwater. This results in a decreased water quality in the aquifer which can affect the ecosystems dependent on that groundwater and, potentially, render it unfit for consumption. Sea-level rise amplifies this effect.
In summary, groundwater contamination may render the aquifer unusable to humans and the ecosystems that depend on the aquifer [15].
The range of uses and users of groundwater and the fact that it is, literally, underground makes groundwater over-extraction challenging to manage. What follows is a high level discussion of some approaches to doing so.
Managing groundwater extraction and addressing the consequences of that extraction requires robust legal and regulatory frameworks to ensure sustainable management of the resource. However, implementing effective regulations faces a number of challenges:
Creating sharing agreements requires collaborative approaches that prioritize long-term sustainability over short-term gains which is not easy when parties to the agreement have pressing needs which require addressing in the short term. The work of the Prairie Provinces Water Board is a promising step in the right direction at the inter-jurisdictional level. At an international level, the United Nations General Assembly has endorsed a set of 19 draft articles related to groundwater for use in the management of transboundary aquifers [20].
Relevant legislation and regulations need to be established and enforced to ensure extraction does not exceed recharge rates. This can include permitting systems for well drilling and caps on the amount of groundwater that can be extracted.
It is difficult to effectively manage something which is not well understood. Groundwater data is lacking in many areas, especially in the Global South [21], and that lack of data can make effective management of the resource impossible [22]. A further complication is that even when necessary information is known, it is not always available to elected decision makers (e.g. government ministers) who may be setting policy. Even if the information is available, the decision-makers are typically not groundwater specialists, and so may lack the knowledge of how best to use that information [23].
Groundwater levels and usage must be monitored to detect over-extraction trends early, allowing for timely interventions. Strengthening monitoring and enforcement mechanisms is essential to ensure compliance with regulations and prevent over-extraction and pollution of groundwater resources.
Managed Aquifer Recharge (MAR) is a process whereby aquifers are deliberately recharged in some way [24]. In effect, excess surface water is directed into aquifers during wet periods to enhance groundwater supplies. The suitability of methods depends on factors such as the quality of the water source, local soil and hydrogeology conditions and local land use. For example, there may be little point in recharging an aquifer if the recharge water moves beyond future reach or is contaminated while underground.
It should be noted that MAR is relatively expensive with costs estimated at US$0.04 – US$1.61 per cubic metre of water although it was estimated in 2019 that global MAR has reached 10 cubic kilometres of water [25]. MAR can be done in several ways:
In urban areas, it is possible to encourage the creation of recharge zones, such as parks, stormwater ponds, bioswales, wetlands and open spaces that allow rainwater to percolate into the ground, reducing surface runoff and replenishing groundwater supplies [27]. These spaces may also offer other benefits such as flood mitigation, urban cooling and various mental health benefits such as lowered stress levels. Such nature-based solutions oriented or “Enhanced Aquifer Recharge” approaches tend to be cheaper to implement than more complex MAR mentioned above.
Groundwater is a hugely important but largely invisible resource which, in many parts of the world, is being used unsustainably. In many respects, groundwater over-extraction is a classic “tragedy of the commons ” [29]. However, given the severity of the consequences of damaging or destroying the resource, there is an urgent need to rethink how we manage and use groundwater.
We need to improve our governance of groundwater by ensuring that our governance and water management structures at the international, national, sub-national and community levels of society are fit for purpose. We need to address gaps in our knowledge and ensure that decision-makers are both informed and able to use that information. We need to involve all stakeholders in developing sustainable management of a common and shared resource.
Ensuring the sustainable use of groundwater is not only critical for the health of the planet’s ecosystems but also for the well-being and prosperity of communities worldwide now and in the future. The balance between utilizing groundwater resources and preserving them for future generations is a delicate one, requiring informed decision-making, cooperation, and commitment at all levels of society.
Become informed! If you’re in an area where groundwater is being used, doing nothing will probably result in the unsustainable extraction of groundwater in your area with long-term consequences ranging across issues such as ground subsidence, groundwater contamination, negative economic outcomes and ecological changes. So:
Educating children about the dangers of groundwater over-extraction is crucial for fostering a generation that values and practices sustainable water use. Teachers can implement various education campaigns and activities that are engaging, informative, and age-appropriate. Here are some strategies and ideas:
By implementing these educational campaigns and activities, teachers can instil an understanding of the critical role groundwater plays in our environment and the importance of conserving this precious resource. Engaging students in hands-on learning, critical thinking, and community involvement prepares them to be informed, responsible citizens who can contribute to sustainable water management efforts.
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Ross has extensive executive experience in Operations, Governance, Information Technology and Strategy at the board and senior management level including Mancal Corporation, Mancal Energy, Highridge Exploration and Atlantis Resources. He has worked in Oil and Gas, Coal, Commercial Real Estate, Portfolio Management, Recreation, Retail and Water and Wastewater Treatment. His experience is also geographically diverse having overseen operations in Canada, the United States, United Kingdom and Northern Ireland. Additionally, he has been on the board of companies with operations in Argentina, Azerbaijan, Barbados, Kazakhstan, and Russia. He has served on numerous Public, Private and Not for Profit Boards across a number of industries.
Ross has been active on several industry Boards and committees including the Canadian Association of Petroleum Producers (CAPP) and The Schulich School of Engineering Industry Advisory Council at the Schulich School of Engineering.
Brian is a seasoned Cleantech entrepreneur with a proven history of successfully bringing complex water technologies to the market. With over 25 years of experience, he has led various organizations to achieve significant milestones in the industry.
Having started as the founding CEO of the Pressure Pipe Inspection Company (PPIC) and later taking the helm at the Water Technology Acceleration Project (WaterTAP), Brian’s entrepreneurial spirit has been instrumental in driving innovation and growth within the sector.
He is an active investor in the cleantech sector and has served on many boards including the Ontario Clean Water Agency.
Actively engaged in industry associations like AWWA, WEF, IWA, and ASCE, Brian enjoys collaborating with fellow professionals to promote advancements in the field.
Brian holds an undergraduate degree and a PhD in Physics from Queen’s University, which has provided him with a solid technical foundation. As a member of the Institute of Corporate Directors, he brings valuable insights to corporate governance.