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The International Day of Action for Rivers on Thursday passed by without a murmur in Bangalore. A city that drew on two reservoirs of the Arkavathy for its water supply, now has no words

left for the river that satiated a third of its water needs. Yet, plans to rejuvenate it cannot be implemented given the existing knowledge gaps on the issue, says Subir Ghosh March 14 is

observed as the International Day of Action for Rivers. Every year, thousands lift their voices to celebrate the world’s rivers and those who struggle to protect them. Yet, this Day went

virtually unremembered and unobserved this year in Bangalore. Historically, the city may not have cropped up by a riverside, but it is not that Bangalore has nothing to do with rivers. The

city is located in the 4,253 sq km Arkavathy basin, and there is another river (Vrishabhavathy), for all practical purposes now only a stream, that flows out of the city carrying all the

heavy metals that you know to be toxic. One of the two major tanks of the Arkavathy river has dried up and now longer overflows downstream (Hesaraghatta). The other one (Thippagondanahalli,

or TG Halli for short) is barely able to supply 30 million litres per day (MLD) to Bangalore, far lower than the design capacity of 148 MLD. In other words, the river has outlived its

utility. It’s a different thing that the river once took care of water needs of a third of Bangalore’s population. The state government has earmarked funds for rejuvenation of the Arkavathy

basin, but it is a plan many deem to be doomed given that it is moored more in rhetoric than in facts. There are far too many knowledge gaps that need to be bridged before the city and its

authorities concerned can salvage the damage that has been wrought on the Arkavathy. Whether there is sufficient water to meet the current needs of users in the Arkavathy sub-basin and which

users face water scarcity, where and when, is the first poser, Lele and his team of researchers have said in a soon-to-be-released situational analysis. The spatial patterns and extent of

domestic water scarcity is still quite unclear. In rural areas, data from the National Rural Drinking Water Programme (NRDWP) reflect only installed capacities and do not include self-supply

(like drilling one’s own borewells), not to mention, seasonal variation. While overall scarcity in Bangalore city itself is not so high, pockets of scarcity are not clearly identified and

the understanding of scarcity is much weaker for small towns. There are four Class II towns: Doddaballapur, Nelamangala, Ramanagara and Kanakapura drawing water from the same soon-to-be-arid

basin. In the case of agriculture, it is not yet clear to what extent farmers are facing borewell failures and reductions in tank irrigation are being compensated by borewells and by shifts

to drip irrigation. Thus, the role of water scarcity in influencing agricultural cropping shifts needs to be understood, according to Sharachchandra Lele, senior fellow and convenor with

the Centre for Environment & Development at the Ashoka Trust for Research in Ecology and the Environment (ATREE). Little is known about commercial and industrial use of water, and

whether such activities are seriously affected by scarcity of water. And the fact that innumerable agencies are responsible for water governance on the Arkavathy basin (see graphic) does not

make matters simpler. At a conceptual level, there is little debate and clarity on what constitutes fair or unfair allocation across sectors, or between upstream and downstream users. There

is no formal system of water rights, and the National Water Policy gives priority to domestic needs without clarifying what agriculture or industry might be entitled to. Thus, the

development of a water rights structure is in itself a major need at this juncture. The lack of knowledge about the relationship between upstream groundwater pumping and changing inflows

into tanks or rivers downstream remains a major knowledge gap. Theories abound. “The causes of declining flows in the Arkavathy and TG Halli are yet to be fully understood. There is no

scientific consensus on which of the alternative explanations is dominant,” explains Lele. The sustainability of groundwater extraction here has not been understood, beyond the observation

of dropping groundwater levels. It is also not clear whether and how much water is being pumped from the shallow aquifer versus the deeper aquifer, what the connectivity between these two

(or more) aquifers is, and therefore what the recharge rate of the deeper aquifer is or whether borewells are simply ‘mining’ millennia-old aquifers. ATREE researchers found that while

scarcity is not immediately apparent to many domestic users in Bangalore, the problem has already affected rural pockets, and commercial and industrial users. Similarly, there are a few

major water quality hotspots in the sub-basin, water use is clearly not sustainable, and distribution among users is also not always fair. Many studies examining these dimensions attest to

these findings. Perhaps, the least understood are the specific locations and communities affected by rural water scarcity, the extent to which groundwater is mined, and the impacts on

aquatic ecosystems. Also poorly understood is the water budget for the region vis-à-vis imports from the Cauvery, an aspect that will become important as the Cauvery award is implemented. At

the same time, there are major gaps in the general understanding of the causal pathways of many of these outcomes. For instance, in spite of commissioned studies, the causes of the TG Halli

reservoir drying up remain unclear. This, says Lele, is related in part to the generally poor understanding of linkages between groundwater and surface water and between shallow and deeper

aquifers. The implications of these for sustainability of groundwater are also not understood. Similarly, the sources and contamination pathways of heavy metal pollution in the

Vrishabhavathy and of nitrate pollution in areas are poorly understood as well. In the bargain, what is happening is that water agencies are focusing on immediate supply solutions rather

than long-term sustainability, groundwater extraction being completely unregulated, inter-user norms and priorities being unclear, the implications of the Cauvery Water Dispute Tribunal

(CWDT) award yet to sink in, and the incapacity of the pollution control board to enforce effluent control norms against a city like Bangalore. If science cannot help resuscitate the river,

a requiem for the Arkavathy should be on the cards.