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UCL Department of Risk and Disaster Reduction


The Global Water Crisis is a Local Problem

By Mohammad Shamsudduha, on 11 July 2024

map of arsenic concentrations around the world. A zoomed in image of arsenic concentration in Bangladesh shows higher values in the south of the country close to the Bay of Bengal. Another smaller image shows arsenic incidents and concentrations in a village.
Machine learning algorithm generated map showing groundwater contamination (i.e., probability of arsenic concentrations >10 μg/L which is the WHO standard for drinking water) from a global study.

We often hear that the world is facing an imminent water crisis as demand for freshwater outstrips supply and water quality is degrading globally. This is true for many parts of the world. However, is it accurate to label this a “global water crisis”? The term conjures images of a unified, worldwide struggle against dwindling freshwater resources. This perspective often obscures the true nature of the crisis: a series of highly localised problems that vary significantly from one region to another. Global-level policies, though well-intentioned, frequently fail to address the specific needs and challenges faced by local communities. By examining issues such as groundwater depletion, water quality challenge (e.g., salinity, arsenic, faecal contamination), water poverty, and poor governance, we can better understand why the global water crisis is, in reality, a collection of local problems requiring tailored solutions.

Groundwater depletion in India

According to a World Bank report, India is the largest user of groundwater, extracting over 230 km3 annually, which accounts for about 25% of the global total. Groundwater serves as the lifeline for agriculture, drinking water, and industry across India. Over-abstraction of groundwater, particularly in states like Punjab, Haryana, and Uttar Pradesh, has led to severe depletion of aquifers. This overuse is driven by policies that encourage water-intensive crops and subsidise electricity for pumping water, without considering the long-term sustainability of water resources. Despite global efforts to promote sustainable water use, the issue persists due to the local agricultural practices (e.g., water-intensive rice crop cultivation) and policy incentives that need to be reformed.

Water salinity in coastal Bangladesh

In coastal Bangladesh, water salinity has become a major concern. New research led by a PhD student at RDR shows that reduction in river discharge, rising sea levels, and frequent cyclones, exacerbated by climate change, have increased the salinity of both groundwater and surface water sources. This has made it difficult for local populations to access fresh drinking water and has adversely affected health and agricultural production. Global climate policies may address the broader issue of climate change, but they do not provide immediate solutions to the salinity problems faced by coastal communities in Bangladesh. Localised strategies, such as building freshwater reservoirs, rainwater harvest, and adopting salt-tolerant crops, are essential to address these specific challenges. A study from the World Bank highlights that over 25 million people in Bangladesh are currently exposed to saline groundwater.

Arsenic contamination in Bangladesh and India

Arsenic contamination of groundwater has been a severe issue in parts of Bangladesh and India, particularly in the Ganges-Brahmaputra-Meghna Delta since early 1990s. Millions of people are exposed to arsenic levels far above safe limits, leading to serious health problems. Recent reports show that around 20 million people in Bangladesh and 13 million in India are exposed to very high arsenic contamination in drinking water. While international guidelines and global health policies raise awareness about the dangers of arsenic, the solution requires localised intervention. This includes identifying contaminated wells, providing alternative water sources, and educating communities about the risks and mitigation strategies. Global policies cannot replace the need for targeted, on-the-ground action to manage this public health crisis.

Water poverty in Sub-Saharan Africa

Water poverty remains a significant challenge across various regions globally, impacting millions of people daily. In many parts of Sub-Saharan Africa, access to clean water is a daily struggle. Water poverty, defined by lack of access to adequate, safe, and affordable water for a healthy life, affects millions. Global initiatives often focus on large-scale infrastructure projects, but these can overlook the specific needs of remote or impoverished communities. Local solutions, such as community-managed water supply systems, rainwater harvesting, and mobile water treatment units, can be more effective in addressing the unique challenges faced by these populations. According to the United Nations, over 400 million people in Sub-Saharan Africa lack access to basic drinking water services.

Sewage disposal and water pollution in the UK

Here in the UK, ongoing issues with sewage disposal by water companies highlight significant governance failures in managing water resources. Water companies have been criticised for discharging untreated sewage into rivers and coastal waters, leading to severe water pollution. This practice has contaminated waterways, affecting ecosystems and public health. Despite regulatory frameworks intended to protect water quality, enforcement has been lax, and infrastructure investments have lagged. According to the Environmental Agency, in 2023, England’s rivers and seas endured over 3.6 million hours of untreated sewage discharges, a 54% increase from the 1.75 million hours in 2022, with the total number of spills reaching 464,000​​. This severe water pollution impacts ecosystems and public health, underscoring the urgent need for stronger local governance and enforcement to address these issues effectively. Watershed Investigations has recently published a UK-wide map of water pollution that contains 120 datasets, ranging from river health, bathing water health, to historic landfill sites, sewage dumping, intensive farming, heavy industry and more.

Global awareness and local realities

While the global narrative of a water crisis is useful in creating public and policy awareness, it often fails to solve specific local problems on the ground. Unlike the global climate crisis, which is primarily driven by carbon emissions affecting the entire planet, water issues are highly localised and influenced by regional natural and anthropogenic factors.

Global policies tend to generalise the water crisis, leading to solutions that do not fit local contexts. For instance, the UN’s global water development report highlights broad issues, but without localised strategies, these insights do not translate into actionable solutions on the ground. Global campaigns such as the Sustainable Development Goals (SGD) may raise awareness, produce lots of reports, and mobilise resources but fall short in addressing specific local challenges such as the infrastructural deficits in Sub-Saharan Africa or the unique ecological impacts on Bangladesh’s coastal regions due to water and soil salinity.

Addressing the global water crisis through localised strategies is essential for real change. For instance, India’s severe groundwater depletion due to over-extraction for agriculture necessitates local policy reforms and sustainable water management practices. Coastal Bangladesh faces increasing water salinity from rising sea levels and cyclones, which can be mitigated through localised solutions like freshwater reservoirs, rainwater harvesting and salt-tolerant crops. In Sub-Saharan Africa, sustainable groundwater development, including managed aquifer recharge, solar-powered boreholes, and community-based management, effectively addresses water scarcity. The UK’s severe sewage disposal issues underscore the importance of stringent governance, regulation, and infrastructure investments. These examples illustrate that while global awareness is important, tailored, region-specific interventions (“global water crisis but local solutions”) are critical for effectively addressing diverse water challenges worldwide.

Dr Mohammad Shamsudduha | Department of Risk and Disaster Reduction

Dr. Mohammad Shamsudduha (Shams) is an Associate Professor at UCL RDR, specialising in water crises and risks to human health, irrigated agriculture, and climate adaptation. His research focuses on sustainable water management, water risk, and resilience strategies, with significant contributions to understanding groundwater quality and quantity crises around the world. Dr. Shams has been promoted to Professor of Water Crisis and Risk Reduction, effective from October 2024.

The views expressed in this blog are those of the author(s).

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Mapping the world’s largest hidden resource

By Mohammad Shamsudduha, on 15 February 2024

photograph of a water pump in wet agricultural land
Groundwater-fed irrigation in southwest Bangladesh (credit: Ahmed Rahman, UCL IRDR)

Water sustains life and livelihoods. It is intrinsically linked to all aspects of life from maintaining a healthy life, growing food, and economic development to supporting ecosystems services and biodiversity. Groundwater—water that is found underneath the earth’s surface in cracks and pores of sediments and rocks—stores almost 99% of all liquid freshwater on Earth. Globally, it is a vital resource that provides drinking water to billions of individuals and supplies nearly half of all freshwaters used for irrigation to produce crops. But are we using it sustainably?


Groundwater is dug out of subsurface aquifers by wells and boreholes, or it comes out naturally through cracks of rocks via springs. Today, about 2.5 billion people depend on groundwater to satisfy their drinking water needs, and a third of the world’s irrigation water supply comes from groundwater. It plays a crucial role in supplying drinking water during disasters such as floods and droughts when surface water is too polluted or absent. Despite its important role in our society, the hidden nature of groundwater often means it is underappreciated and underrepresented in our global and national policies as well as public awareness. Consequently, A hidden natural resource that is out of sight is also out of mind.

Some countries (e.g., Bangladesh) are primarily dependent on groundwater for everything they do from crop production to the generation of energy. Other countries like the UK use surface water alongside groundwater to meet their daily water needs; some countries (e.g., Qatar, Malta) in the world are almost entirely dependent on groundwater resources. Because of its general purity, groundwater is also heavily used in the industrial sector.

photograph of man taking measurements at a borehole
Measuring groundwater levels in a borehole in Bangladesh by IRDR PhD student Md Izazul Haq


Despite our heavy reliance on it, there is a lack of groundwater monitoring across the world. Monitoring of groundwater resources, both quality and quantity, is patchy and uneven. Developed countries like Australia, France and USA have very good infrastructure for monitoring groundwater. Monitoring is little or absent in many low- and medium-income countries around the world. There are some exceptions as some countries in the global south such as Bangladesh, India and Iran do have good monitoring networks of groundwater levels.

Groundwater storage changes are normally measured at an observation borehole or well manually with a whistle attached to a measuring tape, so when it comes into contact with water, it makes a sound. It can be also monitored by sophisticated automated data loggers. Groundwater can be monitored indirectly using computer models and, remotely at large spatial scales, by earth observation satellites such as the Gravity Recovery and Climate Experiment (GRACE) twin satellite mission. Models and satellite data have shown that groundwater levels are falling in many aquifers around the world because of over-abstraction and changes in land-use and climate change. However, due to lack of global-scale monitoring of groundwater levels, mapping of world’s aquifers has not been done at the scale of its use and management.

Current research

New research published in Nature (Rapid groundwater decline and some cases of recovery in aquifers globally) led by researchers from UCL, University of California at Santa Barbara and ETH Zürich has analysed groundwater-level measurements taken over the last two decades from 170,000 wells in about 1,700 aquifer systems. This is the first study that has mapped trends in groundwater levels using ground-based data at the global scale in such an unprecedented detail that no computer models or satellite missions have achieved this so far. The mapping of aquifers in more than 40 countries has revealed great details of the spatiotemporal dynamics in groundwater storage change.

The study has found that groundwater levels are declining by more than 10 cm per year in 36% of the monitored aquifer systems. It has also reported rapid declines of more than 50 cm per year in 12% of the aquifer systems with the most severe declines observed in cultivated lands in dry climates. Many aquifers in Iran, Chile, Mexico, and the USA are declining rapidly in the 21st century. Sustained groundwater depletion can cause seawater intrusion in coastal areas, land subsidence, streamflow depletion and wells running dry when pumping of groundwater is high and the natural rates of aquifer’s replenishment are smaller than the withdrawals rates of water. Depletion of aquifers can seriously affect water and food security, and natural functioning of wetlands and rivers, and more critically, access to clean and convenient freshwater for all.

The study has also shown that groundwater levels have recovered or been recovering in some previously depleted aquifers around the world. For example, aquifers in Spain, Thailand as well as in some parts of the USA have recovered from being depleted over a period of time. These finding are new and can shed light on the scale of groundwater depletion problem that was not possible to visualise from global-scale computer models or satellites. This research highlights some cases of recovery where groundwater-level declines were reversed by interventions such as policy changes, inter-basin water transfers or nature-based but technologically-aided solutions such as managed aquifer recharge. For example, Bangkok in Thailand saw a reversal of groundwater-level decline from the 1980s and 1990s following the implementation of regulations designed to reduce groundwater pumping in the recent decades.

Groundwater is considered to be more resilient to climate change compared to surface water. Experts say climate adaptation means better water management. Globally, the awareness of groundwater is growing very fast. It has been especially highlighted in the latest IPCC Sixth Assessment Report, the UN World Water Development Report 2022 (Groundwater: Making the invisible visible), the UN Water Conference 2023, and more recently in COP28 (Drive Water Up the Agenda). Groundwater should be prioritised in climate and natural hazard and disaster risk reduction strategies, short-term humanitarian crisis response and long-term sustainable development action.

Read the full nature article.

Dr Mohammad Shamsudduha “Shams” is an Associate Professor in IRDR with a research focus on water risks to public health, sustainable development, and climate resilience.

The views expressed in this blog are those of the author.

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