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World Water Day: Rural Water Planning is Caught Between an Egg Carton and a Bathtub

World Water Day: Rural Water Planning is Caught Between an Egg Carton and a Bathtub

A farmer gazes at his field in Anad, Kerala, June 2018. Photo: Nandhu Kumar/Unsplash

  • Groundwater in India is abstracted by millions of small farmers, who typically own 2-10 acres of land.
  • They make pumping decisions based on the availability of water and electricity, and the types of crop that will help them maximise income while minimising risk.
  • The twist is that aquifers – from where farmers pump groundwater – behave differently based on rainfall and geology. 
  • Understanding how farmers behave when faced with different aquifer behaviours is therefore key to solving this puzzle. 

India faces a looming groundwater crisis. The Central Ground Water Board estimates that groundwater in about a quarter of India’s blocks are overexploited or critical.

But to be able address this effectively, we need solutions to work at scale and a clear grasp of ‘what works where’. Can better information about groundwater use and impact of past interventions prompt behavioural change among farmers? Why does this succeed in one place but fail in another ?

To solve this puzzle about why informational interventions seldom scale well requires understanding how groundwater works, how information about it is used, by who, how and why. Interventions need to be tailored specific to how farmers might behave, which in turn depends on the aquifer’s characteristics.

State responses to depletion

The common approach to groundwater depletion, enshrined in programmes like the Jal Shakti Abhiyan, has been to harvest as much rainwater as possible before it ‘runs off’ the watershed. This idea has merit  – slowing down the flow of runoff, allows the water to percolate and recharge aquifers (underground water bearing layers of rock or sediments that store water) locally.

However, harvesting rainwater doesn’t really create ‘new water’. It merely captures water that might have otherwise flowed downstream. In many parts of semi-arid India, stream-flow has declined in part because of diversions for various purposes, to the point that there is very little rainfall left to harvest in most years. As a result, there has been a shift toward demand-side management, i.e. agricultural practices and crop choices that use water more prudently, and participatory groundwater management in such watersheds.

Recognising the need to focus on demand management, the Indian government has launched several schemes including Atal Jal Yojana that require communities to prepare water security plans. Water security plans outline the water challenges of a region and suggest interventions to address them. But a review of water security plans showed that many suffer from both a data and capacity gap, in being able to estimate the amount of water available and in use accurately.

In November 2021, CSEI-ATREE launched Jaltol V1 –  a free, open-source water-accounting tool that makes water balance estimation easy in grassroots communities.[footnote]The author works at ATREE.[/footnote] The Jaltol plugin simplifies the most technical part of the water balance estimation exercise. Yet, one of the questions we frequently get is, “But how does correctly estimating the water budget actually induce change in farmer behaviour?”

To understand this, we need to first understand how and why having better information might induce communities to manage water better.

Informational interventions

Groundwater in India is abstracted by millions of small farmers (who typically own 2-10 acres of land). They make pumping decisions based on the availability of water and electricity, and the types of crop that will help them maximise income while minimising risk. The twist is that aquifers – from where farmers pump groundwater – behave differently based on rainfall and geology.

Understanding how farmers behave when faced with different aquifer behaviours (e.g. how quickly water tables rise and fall in response to rainfall and pumping, how small the aquifers are) is, therefore, key to solving this puzzle.

The simplest distinction of aquifers in India is unconsolidated (alluvial) vs consolidated (crystalline hard rock) aquifers. Unconsolidated sediment contains granular material such as sand, gravel, silt, and clay.

Consolidated rock may consist of such materials as sandstone, shale, granite, and basalt. Unconsolidated aquifers occur along the coastal regions and the Gangetic plains, while much of peninsular and western India is hard rock. (There are, however, subtle differences between the granites and gneisses of Karnataka, Andhra Pradesh and Tamil Nadu; basalt aquifers of Maharashtra; and sandstone aquifer systems of Gujarat).

Image: USGS

These aquifers differ in the extent to which local rainfall and pumping affect the water table locally. To explain how farmers interact with aquifers, economists have traditionally asked whether the aquifer could be treated, from an individual irrigator’s point of view, as an ‘egg carton’ or a ‘bathtub’ (originally proposed in 1981). The egg carton analogy assumes that the aquifer is local and therefore the pumping impacts are local and experienced by a small group of people  –  say one or two villages.

In India, the hard-rock aquifers of peninsular India tend to behave like egg cartons. They are fast responding and local –  like filling and emptying the individual cups in an egg carton. They quickly empty in the dry season if local rains have been deficient but also fill up in wet years. The filling and emptying is driven by local rainfall and local pumping and relatively insulated from what happens in the neighbouring district or state.

The massive alluvial aquifers in the Indo-Gangetic plain behave more like a massive bathtub. In such a system, each farmer’s pumping has a relatively small impact as water moves relatively quickly across the aquifer system. These systems don’t respond much to local rainfall . If pumping exceeds recharge, these aquifers gradually get drawn down over decades like a bathtub that’s leaking faster than the tap filling it.

Behavioural change and collective action

These metaphors have traditionally been used by economists to understand who is impacted by pumping. But in the Indian context, they are equally useful to understand where collective action might work.

Our fieldwork in Anantapur and Maharashtra, where participatory groundwater management has been successful, found that farmers are well aware of the behaviour of the aquifer underlying their villages

Since they live in an egg-carton aquifer, they are motivated to attempt to institute some manner of pumping regulations across the aquifer in order to maintain local groundwater levels. They know that the aquifer is fast responding, so if they over pump in a dry year, they will collectively lose their winter crop as the aquifer dries up. They know that if all the farmers in the village collectively agree on growing less water-intensive or only cultivate a part of their land in a dry year, that would assure everyone continued access to their water and a guarantee that their winter crop will survive. Even if the neighbouring village pumps water excessively, their wells would still be protected.

This is why participatory groundwater management works here  –  collective action is spurred by farmers acting in their own self-interest. In egg-carton aquifers, helping farmers budget accurately can help communities collectively change behaviour.

In Punjab, the situation is very different. Interviews with local organisations show that farmers know they live in a bathtub aquifer. They know that even if they and their immediate neighbours agree to pump less, neighbouring villages can suck the water out from under them. And because they do not experience seasonal or dry-year drops in the water table, the immediate risk to their crops from long-term groundwater depletion is minimal.

The aquifer underlying the Indo-Gangetic plain is a very slowly draining system that they share with millions of others across many districts and states. As long as they occasionally deepen their wells (and budget for it) they can chase the water table.

Simply put, farmers in these regions have no incentive to collectivise. If farmers have no incentive to engage in collective action, the only way to change behaviour is individual incentives that somehow allow farmers to earn more while pumping less. In such situations, solar irrigation, or simply, guaranteed prices for low-water-using crops may all work, but participatory groundwater management won’t. In bathtub aquifers, helping agencies budget accurately can help them offer schemes that induce changes in individual behaviour.

We need solutions to work at scale, if we are to solve India’s groundwater crisis. But a key part of this is understanding ‘what works where’. Ultimately, we need better typologies – both of aquifers and socio-economic conditions – that can be mapped to solutions.

Veena Srinivasan is the director of the Centre for Social and Environmental Innovation and Senior Fellow at the Ashoka Trust for Research in Ecology and the Environment (ATREE), Bengaluru.

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