Lack of data, illegal abstraction, population growth, and unsustainable agricultural practices are putting the continued supply of good quality groundwater at risk. Based on an IWA webinar earlier this year, The Source looks at the challenges to managing groundwater faced by water professionals around the world.
To mark this year’s World Water Day (22 March), IWA hosted a webinar with groundwater practitioners from India, Brazil, Africa, and Denmark. The purpose was to explore the significance of groundwater for human needs, particularly in urban areas, and the dilemma between unsustainable abstraction and water-related livelihoods.
Dependency on groundwater
Almost half the global population relies on groundwater, although outside of the USA and Europe limited data inhibits knowledge of just how vital groundwater is.
During the webinar, Julia Gathu of Drilling For Life, Kenya, described the value of groundwater in supporting rural livelihoods and food security, enabling provision of health clinics, and widening access to education across Africa. Many African countries do not meet Sustainable Development Goal 6 (Availability and sustainable management of water and sanitation for all).
Gathu believes that access to groundwater could close this gap, and that reliable groundwater improves life for pastoral communities who suffer conflict, banditry, and cattle rustling when there is a continued lack of access to water.
In Europe, Denmark is 100% reliant on groundwater for drinking (producing 400Mm3/yr) and has a national policy that treatment must be simple, utilising aeration and sand filtration, with production based on clean groundwater. However, according to Troels Bjerre, head of projects at utility VCS Denmark, it is difficult for Danish water utilities to meet drinking water standards without advanced treatment due to intensive agriculture. He added: “Intensive agriculture is one of the major threats towards the quality of shallow and vulnerable groundwater resources. The main issues are the use of pesticides and fertilisers used in agriculture.”
Groundwater and the city – an evolving relationship
As urbanisation accelerates, groundwater problems increase. Dr Stephen Foster, chair of the IWA Groundwater Management Specialist Group, described the direct but invisible relationship between urbanisation and groundwater. Key factors include the location of abstractions (within and outside of urban areas), the relationship with surface water, and critically what happens to sewage and wastewater.
Despite swathes of impermeable land surfaces, urbanisation often leads to increased recharge from mains water leakage and wastewater disposal. Foster confirmed that urbanisation can cause significant degradation to the quality of groundwater, particularly in shallow aquifers. He explained that high-density sanitation results in microbiological pollution and high nitrates that are incompatible with shallow aquifers, such as those along the Brazilian Atlantic coast. One water utility in Natal, north-eastern Brazil, recently abandoned a groundwater source because of very high nitrates from in-situ sanitation, seeking alternative supplies in less densely populated areas.
Pollution is not the only problem. Foster says that “excessive abstraction can cause infrastructure damage if there is land subsidence, and when water tables in urban areas rebound, there can be damage from inundation and uplift problems”. He concludes that urban groundwater needs to be managed practically, otherwise it can be costly and even hazardous. The difficulty is that no single agency is responsible. In the long run, development of conjunctive use of surface and groundwater is recommended, although it is institutionally difficult to organise.
Private urban supplies
In many developing cities, particularly across Asia and Latin America, private self-supply is a major phenomenon. Although this increases the number of people with access to water, private supplies greatly increase the risk of pollution and impacts on human health. Faiz Alam of IWMI India explained that private access to groundwater is important, especially for irrigation and domestic use, as it gives people more control compared to canal or piped water.
The resilience of groundwater to short-term drought combined with energy subsidies that make pumping more affordable has made groundwater a ‘go-to’ source. Alam explained that “initially private supplies were a reaction against poor utility service, and while it reduces demand for the utility, ultimately it distorts water utility operations and has implications on finance.” The other significant consequence of this is over-exploitation. There are now large parts of India where annual abstraction exceeds natural recharge and Alam expressed concerns that groundwater may become inaccessible or highly degraded if levels continue to fall.
Ricardo Hirata, Professor of the Institute of Geosciences at the University of São Paulo, explained that studies in Latin America reveal that around 90% of groundwater use there is illegal, making it impossible to understand and manage the resource effectively. In São José do Rio Preto, Brazil, half a million people are supplied from wells and from the Preto river. Of those wells, 83% are illegal and unofficially meeting 30% of the urban demand. Despite the increasing cost of groundwater, it is still 50% cheaper than the water from the public system and so remains a popular choice. This is a common situation and one which is hiding the importance and vulnerability of groundwater from official data.
Along the Atlantic coastline of Brazil, the potentiometric level of the water table is now 90 metres below sea level. Climate change scenarios used to model recharge and sea level rise in the aquifer supplying the major city of Recife suggest the resource will be lost within 30-40 years if nothing is done.
In contrast, Denmark’s precipitation and geology makes groundwater easily accessible and there is no abstraction without permission. A very decentralised network of 2600 water utilities manage a concession system which has been in place since 1926.
Private groundwater abstraction, especially in urban areas, is increasing in popularity in Africa. Here groundwater is more accessible than ever before as the number of private drilling contractors has heightened competition and reduced drilling costs, and increasing numbers of manufacturers and suppliers are available to support borehole maintenance. However, there are serious concerns about the number of contractors with no hydrogeological training and the prevalence of unregulated groundwater abstraction.
These cases highlight the dilemma around acting on unsustainable groundwater abstraction that is providing drinking water to marginalised communities, ensuring food security and supporting the livelihood of farmers. It is estimated that unsustainable abstraction in India is producing food for 173 million people. Alam emphasised: “Water managers can’t just focus on groundwater metrics, all aspects of the nexus need to be taken into account.” The need is urgent. Research suggests that if nothing is done, groundwater will reduce by 68% and cropping intensity will fall by 20%, triggering major food security issues and subsequently loss of livelihoods.
According to Hirata, these problems persist because countries don’t have the resources to analyse every aquifer and the authorities tend to regulate all aquifers to the same level, with minimal focus on only drawing from the most strategic resources. Weak command and control systems and little pressure from society on governments to respond proactively compound the problem.
Alam highlighted that despite the importance for urban water security, groundwater is a ‘blindspot’ in Indian urban water planning because there is little reliable data, there are no abstraction records, and private wells have become dominant.
Solutions to make groundwater ‘visible’
Across Africa and India, in addition to more readily available drilling, the proliferation of electric pumps is making it easier to access groundwater. In Africa, this is seen as a positive, lifting people out of poverty and ill-health and into education and livelihoods. For example, the Kenyan government is subsidising solar equipment for boreholes, as powered boreholes can serve more people.
Alam highlighted the strong correlation in India between concentrations of electric pumps and the worst groundwater depletion. In these areas energy for irrigation is virtually free, providing no incentive for efficient water use. In both situations managing energy is key to managing groundwater.
In areas blighted by illegal, uncontrolled private boreholes, more education is needed for both communities and governments on the risks and to help encourage legal and sustainable water use. Many key stakeholders have a role to play in ensuring that groundwater is accessible but also well managed. This includes the international donor organisations that fund community projects providing access to groundwater.
Denmark is an example of how targeted measures can protect groundwater from over-abstraction and pollution. To achieve its revised aim of providing 100% drinking water from ‘clean groundwater’ by 2050, water utilities have vigorously targeted demand and land-use management. After introducing a tax on drinking water in 1988 and including the value of water on bills, production has fallen by 50% despite continued urbanisation and population growth.
Groundwater quality is being targeted through strict land-use regulation in areas with strategically important, vulnerable groundwater resources. Afforestation to increase forest cover from 13-25% by the end of the century is a top national priority.
This is supplemented with agricultural land use agreements, the closing of old and unused wells, and public awareness campaigns.
Technology is part of the solution, but Denmark is clear that a purely technological fix could lead to sub-optimal solutions. •
View this webinar at: https://iwa-network.org/learn/groundwater-protecting-tomorrows-resources/
The webinar marked a step on the ‘Road to Copenhagen’ as the IWA World Water Congress & Exhibition in Copenhagen (11-15 September 2022) approaches.
Visit the Groundwater Forum at the World Water Congress, Copenhagen
The Groundwater Forum at the World Water Congress in Copenhagen on 12 September will explore examples of groundwater management from around the globe.
This will include examples from South Africa, Kenya, Australia, the USA and, of course, Denmark, in three sessions focusing on groundwater management, sustainability and the protection of groundwater quality.
Delegates are invited on a technical tour of a water treatment works to find out how Copenhagen protects its groundwater resources and a 3D model of the city’s process for removing chemical solvents from contaminated groundwater can be viewed at the Bella Center.
Young Water Professionals are encouraged to take part in an interactive session on best practices in groundwater management. To find out more about the IWA World Water Congress & Exhibition visit: https://worldwatercongress.org/