The ignored side of the Cauvery debate

The Cauvery dispute has been aggravated by years of water mismanagement in Tamil Nadu and Karnataka. Receiving the right share of the river water alone is will no longer be enough to solve the problem.

Last year saw yet another outbreak of protests over the 125-year-old Cauvery dispute between Karnataka and Tamil Nadu. The demonstrations quickly escalated to violence in both states, leaving two people dead and over 300 arrested for instigating agitations in Karnataka. But while effigies and buses were set on fire, establishments owned by natives of the opposing state attacked, businesses and schools shut down, and the states continued to drag each other to the Supreme Court (SC), a vital point in the debate was overlooked.

In 2007, the Cauvery Water Disputes Tribunal (CWDT), after 16 years of its formation fixed the distribution amount between the states: 419 thousand million cubic feet (TMC) to Tamil Nadu, 270 TMC to Karnataka, 30 TMC to Kerala, and 7 TMC to Pondicherry. But even this final award could not put the conflict to rest as the numbers were far below the expectations of the two main states which overestimated the volume of water carried by the river and wanted 641.5 TMC and 410 TMC respectively.

The allocation by the CWDT was based on the 1900–1907 and 1971–72 flow of the river, which put water availability at 740 TMC. However, unlike the Ganga, the Cauvery does not originate from a glacier, but is fed by rainfall. Hence, it’s only in years of good rainfall that there is ample amount of water to distribute based on the tribunal’s stipulations — scarcity brings out the ugly side of the strife. And in recent years, rainfall patterns in the area as well as the behaviour of Cauvery tributaries have altered considerably, which combined with a multitude of other factors, have increased water troubles, especially for farmers in the Cauvery belt.

Week after week, the SC directed Karnataka to release water to Tamil Nadu last September, orders which the state repeatedly defied due to drought. The Karnataka government asserted that it didn’t even have enough water for drinking purposes, let alone farming. Tamil Nadu, on the other hand, which depends upon water from Cauvery for irrigation during the Samba season before the northeast monsoon sets in in December, blamed Karnataka for making false claims and diverting water from the river to other sources. But no amount of accusations, court verdicts, appeals, protests, or strikes will resolve the problem unless both the states (and Centre) acknowledge that the Cauvery does not have the capacity to meet all their needs.

Receiving the right share of Cauvery water alone will not relieve the states of water shortage. Poor management and unregulated human activity in and around water sources have created a crisis in Karnataka and Tamil Nadu, making the struggle for the river water more desperate. It is likely that the situation will worsen in the years to come as the effects of environmental and man-made changes manifest themselves in irreversible ways. Hence, unless the following aspects are collectively addressed by the state governments, the conflict cannot be resolved:

Change in rainfall patterns

Karnataka and Tamil Nadu’s Cauvery basin reservoirs witnessed a decline in water availability by 30 percent and 49 percent (it is important to note that the capacity of Karnataka’s reservoirs is a quarter less than Tamil Nadu’s) respectively last year as a result of irregular and below average rainfall. According to IndiaSpend, based on a review of national and international studies, “Extreme rainfall events in central India, the core of the monsoon system, are increasing and moderate rainfall is decreasing — as a part of complex changes in local and world weather.” While rainfall is decreasing by two millimetres (mm) per annum in the Cauvery basin in Karnataka, other regions like Bengaluru and Kolar are seeing a rise by one mm. Similarly, the share of the stable southwest monsoon from July to September in Tamil Nadu’s annual rainfall fell from 48 percent to 24 percent, while the erratic northeast monsoon increased. A study by the Bangalore Climate Change Initiative- Karnataka (BCCI-K) says the Cauvery basin will see a decline in rainfall by 20 percent for some districts and between zero and 10 for others in the 2020–2050 period, adversely affecting both the kharif and rabi seasons. Such variations in rainfall and reduced water availability in the Cauvery without a plan to cope with smaller shares will surely intensify the dispute over the next few decades.

Sand mining

Uncontrolled sand mining in riverbeds or along the banks of the Cauvery and its tributaries has altered the course of the river as well as polluted it, leading to contamination of the irrigation and drinking water supply. Despite the ban on illegal sand mining, partnerships between corrupt miners, police, and politicians ensure its continuance. It’s not just the Cauvery but other rivers such as the Coleroon, Amaravathi, Palar, and Vellar in Tamil Nadu, and Kapila and Suvarnavathi in Karnataka that are being abused for sand to provide the construction sector. If such extensive and unregulated sand mining carries on in both states, it will drain the rivers of life.

Decreasing groundwater levels

Rampant exploitation of groundwater has depleted the freshwater source across both states. For example, in Hassan district of Karnataka, the static water level has declined from 8.47 metres (m) to 15 m, i.e., people now have to dig as deep as 800–900 feet for water as opposed to 150 feet only five years ago. In Tamil Nadu, only four out 30 districts recorded a rise in average groundwater level. Chennai recorded a fall from 4.68 m in 2010 to 5.63 m in 2015, and Coimbatore has the lowest level at 13.12 m.

Pollution and land encroachment

The Central Pollution Control Board (CPCB) recently identified 15 polluted rivers in Karnataka, unfit for human consumption. The release of untreated sewage water and industrial effluents into all major rivers including the Cauvery were stated to be the main reasons. Similarly, seven rivers in Tamil Nadu were listed as polluted, with five of them identified as critical by the CPCB. Noyyal, a major tributary of the Cauvery in the state, has been rendered unusable and can no longer provide for the villages in its basin, forcing residents in the area towards other rivers for their supply.

Additionally, agricultural and industrial encroachments are destroying water bodies in both states. For example, the banks of the Bhavani in Tamil Nadu have been occupied by paddy, banana, and turmeric fields to which water from the river is diverted, affecting supply to other farmers in Erode district. Similarly, encroachments by industrial buildings in the Arkavathy river valley killed the water source, which the Bangalore Development Authority (BDA) is now trying to revive to increase the water flow to Thippagondanahalli Reservoir.

Water-intensive cultivation

The two main crops grown in the Cauvery belt are paddy and sugarcane, both of which require a tremendous amount of water (1200 mm and 1800 mm respectively). Dryland crops like ragi on the other hand, need only 500 mm but receive similar support prices. With decreasing precipitation and groundwater levels in Karnataka and Tamil Nadu, existing crop patterns are no longer suitable. In Tamil Nadu, farmers grow three paddy crops in June, August, and September respectively. Switching to less water-intensive crops, at least for one or two seasons, can decrease water stress in the region.

Additionally, practices like the System of Rice Intensification (SRI), which has already been introduced in Tamil Nadu, can reduce water requirement, increase land productivity, as well as reduce dependence on artificial fertilisers. Such sustainable approaches to farming are necessary to adapt to increasing climatic pressures.

Poor water management in cities

Subpar water management in cities like Bengaluru and Chennai is the primary cause of recurring water woes. Water bodies are fast disappearing due to widespread pollution and encroachment by residential and industrial buildings, slums, and encampments. Similarly, uncleaned storage tanks in several areas now have decreased capacities due to silt formation. Additionally, a significant amount of water is lost during transit as well, especially in Bengaluru, decreasing the actual amount of water supplied to the city. Concepts like rainwater harvesting are negligibly applied while borewells are mindlessly drilled deeper and deeper, misusing available groundwater.

While a distress sharing formula is necessary for years of deficit rainfall to avoid a flare up of the dispute, it is important to improve or restore existing sources and encourage water conservation. Inter basin water transfer, a method by which water from the westward flowing rivers of Karnataka (which have a capacity of 2,000 TMC per year) can be diverted to the Cauvery, has been suggested as a possible solution to the conflict. But even this abundant supply could fall short if the states continue to mismanage their water.