Groundwater: A valuable ‘invisible’ resource

The theme for this year’s World Water Day (March 22) ---- “Groundwater: Making the Invisible, Visible” ---- could not be more relevant for India, particularly cities. India is by far the largest user of groundwater in the world, accounting for 25% of the global water withdrawals. Approximately 45% of the water supply in India’s cities is sourced from groundwater. Unfortunately, this dependency on groundwater has not translated into its judicious management. The Central Groundwater Board (CGWB) estimates that about 17% of the groundwater blocks across the country are overexploited, where the rate of extraction is more than that of renewal.

Unlike surface water (rivers, lakes, ponds, etc.), groundwater is “invisible”. A quick internet search will yield that thousands of images of rivers or lakes are victims of encroachment, scarcity, and pollution. But while groundwater faces the same challenges, there is hardly any visual evidence. This is why groundwater-related issues and crises often go unnoticed, especially at smaller scales. It is only when extensive studies involving huge budgets are carried out that these come to the fore.

From an urban perspective, “making the invisible, visible” essentially involves having an improved understanding of this “hidden” resource, and mainstreaming it within the overall water management strategy of the city in a sustainable manner.

How do our cities go about achieving this?

For starters, cities need to map their groundwater resources to develop credible knowledge about the quantity and quality of the resources available. Very few cities in India can claim success with confidence in this regard. Given that most of our urban areas rely heavily on groundwater, having a robust database of this resource is key to informing sustainable strategies to reduce the demand-supply gap.

Encouragingly, an enabling environment for this has already been created with the National Project on Aquifer Management (NAQUIM) initiated by CGWB, and the reforms proposed in the Atal Mission for Rejuvenation and Urban Transformation (AMRUT 2.0) by the ministry of housing and urban affairs. It is now up to the cities to leverage these.

Next, far too often, cities extract way more groundwater than can be replenished naturally. This is the primary reason why cities like Delhi, Bengaluru, and Hyderabad have seen a rapid depletion in their groundwater levels. Researchers coined the term “sustainable yield” of groundwater to address such challenges in the late 1990s. This is defined as the amount of groundwater extraction that can be maintained indefinitely without causing unacceptable environmental, economic, and social consequences.

This concept has already been adopted for groundwater management by several countries across the globe. For example, as early as 1999, the US Geological Survey issued comprehensive national guidelines to ensure the sustainability of groundwater resources in the United States (US). Incidentally, similar to India, groundwater is the source for approximately 51% of the drinking water supply in urban areas in the US. The sustainable yield of groundwater depends upon a number of site-specific factors; therefore, it is vital for our cities to have a contextualised understanding of this parameter to avoid irreversible damage.

As with any management strategy involving natural resources, citizen engagement is vital for success. It becomes even more crucial for groundwater because the “invisible” nature of the resource makes it easy for people to get away with indiscretions. A city may impose all the required regulations to control the extraction of groundwater and incentivise the rejuvenation of depleted groundwater resources; however, monitoring this is a herculean task. With the advent of technology, it is possible to have boreholes as small as four inches in diameter dug as deep as two hundred feet. Even if only 25% of the households in the city have such boreholes, it is still a monitoring nightmare for any city administration. Likewise, households may install a rainwater harvesting unit to avail the incentives provided to do so, or to abide by the mandatory regulations imposed in that regard. But it is challenging for city authorities to ascertain whether these units remain functional year after year.

Citizens will need to step up and share the onus of action. And the first step to make this happen is to engage them in two-way dialogues for building collective consciousness on the need for community ownership of groundwater management.

As the climate crisis concerns escalate, its impacts are causing significant changes in the flow of rivers, and in some cases, a shift in their course. There are, therefore, credible concerns about the access and availability of surface water to meet future water demands of cities. The good news is, unlike some natural resources such as minerals or oil, groundwater is renewable. If managed sustainably, it can continue to serve as a reliable source of water supply for our cities in the future.

Victor R Shinde is lead — Water and Environment, National Institute of Urban Affairs; and Hitesh Vaidya is director, National Institute of Urban Affairs.

The views expressed are personal