Climate change and anthropogenic factors are having a detrimental effect on the Cauvery delta region, a study spanning almost four decades reveals

The Cauvery delta region, widely regarded as the granary of Tamil Nadu, has shrunk, with cultivable lands increasingly deteriorating into waste lands — this is the finding of a recently concluded study undertaken by retired professor of the Madras Institute of Development Studies (MIDS) S. Janakarajan.

Funded by the Indian Council of Social Science Research (ICSSR), the study was conducted between 2014 and 2016 and covers a period spanning almost four decades, beginning from the 1970s. Through the comparison of the geographic information system (GIS) imagery for May 2014 with the 1971 toposheet obtained from the National Remote Sensing Centre at the Indian Space Research Organisation (ISRO), the researcher has tracked land use and changes to land cover to show that the delta region has shrunk by 20% due to anthropogenic factors such as diversion of land for non-agricultural purposes, as well as factors linked to climate change.

For a once-prosperous agricultural belt, the drastic reduction in crop cover and a 13-fold increase in wastelands between 1971 and 2014 indicate a worrisome phenomenon. “Much of this is because the land is kept fallow due to lack of water and other adverse climatic conditions,” Mr. Janakarajan says.

Risk of sinking

Another phenomenon reported by the study is the increase in mangrove cover in the region as sea water ingress has grown in the coastal areas. The data shows that mangrove cover has gone up nearly 14 times since 1971.

“Increasing mangrove cover is nothing to be happy about, because what that means is that more and more cultivable agricultural land is coming under sea water and the soil is turning saline,” Mr. Janakarajan says. With 72% of the low-lying land in the State falling under the delta region along the coast, the land in this region is at greater risk of submergence as a result of rising sea levels due to climate change. The author cites studies by Sujatha Byravan and others to show how a substantial portion of land in the delta region is at an elevation of merely a metre from the sea. He raises the issue of reduced sediment flow to the delta, which otherwise helps maintain the critical elevation level from the sea.

“There is an almost near-unanimity among researchers that the withholding of the river flow upstream through the construction of a series of dams is the fundamental reason for the reduced or no sediment flow downstream, and that delta subsidence [ Imminent threat to coastal populations] is in a large measure attributable to these kinds of human intervention in the rivers,” Mr. Janakarajan says, pointing out that the Cauvery delta has witnessed a decline of 80% in sediment deposit over the last century.

This is borne out by the loss of storage capacity in the Mettur dam as a result of siltation, for instance. The dam, constructed in 1934, used to have a storage capacity of 2708.8 million cubic metres (MCM). By 2004, this was reduced to 1994.2 MCM. Besides, data reveal that its capacity had reduced further to 1,889 MCM in 2015. Sediment flow to the Cauvery delta has been practically nil of late, as per a 2015 report by the Central Water Commission cited by the study.

Cycle of drought and flood

A noticeable consequence of climate change has been the cycle of drought and flood that coastal areas have been enduring. While there has been a decline in the overall rainfall between 1974 and 2004, the study reports an increase in rainfall, occurring in spurts, at the local level. The overall decline in rainfall has not been borne out across the Cauvery basin in the State. During several years, the delta districts received 1,200 mm of rainfall, which is high. However, this pattern has not spread out. Usually, the rain occurs within a span of a few days, resulting in heavy flooding. The fields get flooded and the crops are destroyed. On the other hand, there is the prevalence of droughts such as the one that the State is currently reeling under.

All these factors have resulted in a drastic reduction in land under crop cover to the tune of 27%, as against 1971 levels. Due to sea water ingress, there has been a substantial rise in shrimp farming along the coast, which is detrimental to agricultural practice, the author points out.

Periodic storm surges in the delta region have exerted additional stress on the 14 tail-end regulators in the canals at Nagapattinam district, which help keep sea water at bay. These regulators help divert the drainage water flowing from the Cauvery river system for irrigation purposes, which would otherwise end up in the sea. The total area irrigated by the water impounded by these regulators is 25,509 hectares. With a rise in sea levels, this arrangement could turn dysfunctional.

Another major vulnerability is the soil type. “The delta region has clay soil, of which 52% is cracking clay, which is very vulnerable if it doesn’t receive continuous irrigation,” Mr. Janakarajan says.

The study also points to the decline of dairy as a secondary occupation in the delta districts, with the cattle population also registering a steep decline, as revealed by the livestock census data. This means that when agriculture fails to support farmers, back-up options such as livestock and poultry rearing may not be of much help either. “Poultry farming cannot withstand rough weather conditions, which are not uncommon for the delta,” the author observes.

The decline of agricultural prospects in the Cauvery delta has been disastrous for the socio-economic well-being of the local population. Indebtedness is a major issue and alcohol addiction is high as job opportunities decline, the study shows. Economic vulnerability is very high, the author warns.

What farmers say

Voices from the Cauvery delta region have shed some light on the ground reality, as well as the sort of State intervention which might help tide over the current crisis.

Voicing his concerns over the implications that the decline in land under crop cover may have for food security, Mannargudi S. Rangathan, general secretary, Tamil Nadu Cauvery Delta Farmers’ Welfare Association, says, “Food security is of utmost importance and the delta region plays a very important role in this regard. In the face of changing climatic conditions and sea-level rise, both the government and the farmers must devise strategies that will help address the situation rather than merely throwing up their hands in despair.”

“The former Thiruvarur Collector, S. Natarajan, undertook a very good rainwater harvesting effort in the delta areas, which helped farmers to produce a bountiful harvest later on. This is just one instance of how, even during a water crisis, timely government intervention could help address some of the problems identified by the MIDS report,” he says.

However, not all farmers are happy with the way the State has intervened to address the crisis in the delta districts. P.R. Pandian, president of the Tamil Nadu Farmers Association, says that although several schemes have been announced by the State for the farmers’ welfare, it remains unclear as to who is benefitting from them.

Recently, the treasurer of the association, S. Kannappan, sought details under the Right to Information Act regarding the implementation of the livestock fodder distribution scheme, under which farmers are eligible for 22 kg of livestock fodder per cow per week.

“No farmer that I know in my village has received any livestock fodder under the scheme, though in the RTI documents, the government has accounted for all the money on paper,” Mr. Kannappan claims. He says depots were proposed under the programme for distributing the fodder, but he couldn’t find any in his area. Farmers in the delta region have particularly been hit hard by the recent drought, and are struggling to feed their cattle, with many selling them under distress, he says.

Building resilience

Mr. Pandian further points out that with the objective of improving irrigation structures to benefit farmers, the government had envisaged the strengthening of irrigation canals and bunds to handle incidents such as floods. However the Public Works Department (PWD) has been moving at a snail’s pace on this project while contractors have been swindling money.

One thing that the study makes clear is that there is no escaping the need to build resilience, in the light of climatic changes. The Tamil Nadu State Climate Action Plan, drafted in 2014, anticipates many of the challenges that the report has raised, and envisages a slew of measures to make agriculture sustainable, given the climate variability. Promotion of drought- and flood-tolerant varieties of paddy, micro-irrigation to promote efficient use of water and use of bio-fertilizers to improve soil health are among the proposals aimed at helping farmers improve their yield with available resources.

However, there is no clarity on the extent to which these proposals have been incorporated in government interventions. H. Malleshappa, Director of Environment, claims that most of what the report advocates have already been implemented by the departments concerned such as the PWD and the Department of Agriculture, adding that ultimately, only the individual departments could account for the progress made, and he can’t answer on their behalf.

Agriculture Secretary Gagandeep Singh Bedi says the State would, in the future, adopt two varieties of paddy recently developed by the Tamil Nadu Agricultural University, which are said to be flood- and drought-tolerant.

Though the work on introducing climate resilient crop varieties is only beginning, the efforts of the State thus far have placed greater focus on promoting efficient use of water in agriculture through the expansion of the System of Rice Intensification (SRI).

“Now, almost 60% of paddy grown in Tamil Nadu is covered under SRI,” Mr. Bedi says, adding, “We have also placed emphasis on crop rotation and are asking farmers to grow pulses, millets or cotton after paddy cultivation. Further, we have also encouraged cultivation of black gram by the bunds of paddy fields to ensure nutritional value of soil.”

However, wasteland reclamation work is currently concentrated in the dry regions of Tamil Nadu around the Mettur dam, Pennaiyaar basin and parts of Krishnagiri, and not in the Cauvery delta regions.

The State government’s 2017-18 policy note on agriculture admits that agricultural production has been severely affected due to natural factors such as cyclones and drought. Though it outlines several schemes for the benefit of farmers and also uses the term ‘climate-smart’ numerous times, it lacks clarity on the specific resources that would be dedicated to developing such ‘climate-smart’ practices. One promising initiative is the collective farming scheme, which aims to promote farmer-producer groups with a corpus fund of ₹5 lakh per group. This will help reduce the vulnerability of small and marginal farmers to natural hazards as it allows them to pool their resources and scale up farm production. However, these schemes have only been proposed for the dry regions of the State, rather than delta regions. Agriculture Minister R. Doraikannu points out that the State government has announced a sustainable agriculture programme focused on rain-fed areas to promote dry land agriculture. But this does not cover the delta regions. He also notes that ₹1,250 crore has been released to insurance companies towards crop insurance payments for drought-affected farmers across the State.

That said, the worsening economic vulnerability of the delta farmer is a clear indication that something is amiss despite the climate action plans drawn up by the State. With the Cauvery delta region accounting for 30% of the food grain production in the State, it is imperative that the crisis engulfing the region is resolved sooner rather than later.