Southwest monsoon, Tamil Nadu’s ‘other’ monsoon, is setting the year on fire

One month is left for the Southwest Monsoon to officially return. But Tamil Nadu, for which it is not even the primary monsoon, is enjoying a bountiful monsoon with 90% surplus rainfall (as on 2nd September). While this has had a massive impact on major reservoirs in the state, which are rapidly filling up, concerns about crop losses and optimum utilization of surplus water cannot be ruled out.

Incessant rains in most of the districts mean that the 90 reservoirs are at about 88.70% of their capacity. In this monsoon, about 18 districts have recorded more than 100 percent rainfall.

This year August proved to be a record breaking month. Meteorologists said this is the third highest rainfall in 122 years as the state has received 93% more rainfall than the monthly average. The copious flow in the Cauvery set a new record for water receipts from Karnataka, the volume of which crossed 200 thousand million cubic feet (tmc ft).

This year, the Mettur dam has maintained its absolute level of 120 feet for the last 50 days. Earlier, it was filled for 78 days in 1959, 62 days in 1981 and 60 days in 1961. According to officials, this year the dam has a chance of breaking its record of maintaining its absolute level for more than 78 days. Water Resources Department (WRD).

The Agriculture Department has said that heavy rains in Karnataka and Kerala have also brought water to major reservoirs this season. Agriculture Secretary C. Samaymurthy has said that about 80,000 acres of Kuruvai paddy has already been harvested in the Cauvery delta region. The Mettur dam was opened on May 24, 19 days before the customary date of June 12, and this helped in early harvest. The area under Kuruvai paddy this year in the Cauvery delta region has crossed 5.36 lakh acres, which is the highest in the last 40 years.

There have also been cases of crops being submerged. District officials have been directed to assess the area where the yield loss due to crop damage is more than 33 per cent. Shri Samayamurthy said that farmers are also being advised to take precautions like harvesting coconut, supporting banana trees and removing excess water from their fields.

request for better use

However, the abundant inflows in the Cauvery and Kolidam, which have swelled thrice since July with flood discharges from the Mettur dam, have not directly benefited agriculture in the Cauvery delta region, say farmers.

PR Pandian, chairman of the coordinating committee of all farmers’ unions of Tamil Nadu, expressed regret, saying, “We have not benefited from the heavy floods from Karnataka, but it has gone into the sea to a large extent.”

There has been an uproar over projects to increase storage. The Kaveri-Vaigai-Gunder link scheme, which envisages diverting flood flows in the Cauvery to water-scarce southern districts, has taken some small steps in recent months.

Mr. Pandian blames the lack of planning for the state’s inability to tap the flow in the Cauvery during surplus years. Instead of citing financial constraints, the government should constitute a committee of experts to recommend measures.

Given the limited scope for building storage infrastructure on flat terrain at Cauvery and Kolidam, experts and engineers feel that the time has come to look at alternatives like lift irrigation.

“Floods in recent years have brought 100 tmc ft-200 tmc ft of water into the Mettur dam between June and August. Sixteen pumping stations should be set up at six locations along the banks of the Cauvery and water can be pumped through pipes on either side of the river at Mettur, Jeddarpalayam, Mayur, Mukkombu and Kallanai. Seven barrages should be built at Kaveri and Kolidam. About 50 tmc ft-60 tmc ft can be utilised through these measures,” says A Veerappan, state secretary, Tamil Nadu PWD Senior Engineers Association, a forum of retired engineers of WRD.

Farmer representatives have also criticized the WRD for failing to use the effluent in the Cauvery to fill irrigation tanks in Tiruchi and Thanjavur districts. But WRD officials note that many of the 187 irrigation tanks under the River Conservation Division – including those in Tiruchi, Thanjavur, Karur, Ariyalur and Pudukottai districts – have storages of 50% and above.

Conservation of surplus water remains a challenge in many other districts as well.

While the monsoon has brought abundant water to the Bhavanisagar dam in Erode district, the excess is being released into the Bhavani river because of the Athikadavu-indestructible groundwater recharge and drinking water supply scheme, which proposes to draw water from the river and divert it into tanks. . In Coimbatore, Erode and Tiruppur, not yet completed.

Farmers in five districts of the Madurai region, who are usually demanding release of water from the Mullaperiyar reservoir every year, are happy with the timely release of water in June for two consecutive years. The water released from the Vaigai dam, which has also filled thrice in the last 15 months, is being carried to the tail end in Ramanathapuram and Sivagangai districts. Small and marginal farmers have also swung into action this time.

Efforts to desilt the tanks and ‘Uranis’ have yielded greater flows: the Madakkulam tank in Madurai and the larger tank in Ramanathapuram district are full of water. The farmers of Usilampatti have benefited from the 58-canal scheme in Madurai district.

On the other hand, farmers express concern about surplus in dams for the second year in a row. Last time the rain, just before the paddy harvest, had flooded many fields. While campaigns are being run for insurance of crops, R. Representatives of farmers’ unions like Palanichamy allege that they have not received proper compensation from insurance companies for crop damage.

Experts have suggested that the government explores modalities for formulation of minimum support prices for paddy growers during such situations. Former Tamil Nadu Additional Director (Agriculture) S. Kanagaraj has said that technology should be used to assess the loss accurately and the compensation should be deposited directly into the bank accounts.

Pointing out that other ‘kharif’ crops including maize, bajra and groundnut may not be affected, agriculture experts have called for measures to save paddy, especially in the delta.

SP Ramanathan, head of Tamil Nadu Agricultural University’s Agro Climate Research Center, wants paddy to be harvested in early September depending on the maturity of the crop. In the event of heavy rains, the release of water from the Mettur dam should be temporarily stopped so that the water can escape from the channels and fields.

“Small dams can be built on rivers. We can prevent the damage to Kuruvai crop with appropriate technology. River-linking projects, such as the Cauvery-Gunder link, which will help divert excess water to arid regions, should be expedited,” he said.

The Agriculture Department and the district administration have also taken stock of the situation and initiated measures to minimize the damage. Theni Collector KV Muraleedharan said that sensitization programs were organized for the farmers before releasing the water for irrigation. Disaster Management Plan has also been prepared.

Notification is being issued to enroll farmers in the crop insurance scheme under Rabi season. The state government has provided ₹2,057.25 crore as its share of premium subsidy for the scheme.

The Agriculture Department is also confident of good samba paddy cultivation in 35.8 lakh acres in the delta, which is full of Mettur dam. Chief Minister MK Stalin has got consent from the central government to go ahead with the purchase till September. The state government has fixed the paddy purchase price at Rs 2,160 per quintal for good varieties, says Mr. Samaymurthy.

Chennai Well Established

Healthy storage in reservoirs in and around Chennai has kept the shortage of drinking water at bay this year. The storage in three major reservoirs has already crossed 90% level.

WRD officials said several conservation projects – whether it is to build new reservoirs, improve water bodies around the city and build storage structures in rivers – will take a few years. Meanwhile, efforts are being made to reduce urban flooding.

“We are monitoring the water level and are ready to pre-empt a portion of the storage to maintain a cushion space for heavy inflows during the northeast monsoon. An official says that most of the channels being built as part of flood mitigation projects worth Rs 434 crore will work this year.

more to come?

As per the India Meteorological Department’s prediction for the country, September may also bring heavy rains before the retreat of monsoon. Generally, the Western Ghats districts have an increase during the southwest monsoon over other parts. But, this time it has got a good spell in most areas of Tamil Nadu.

Chennai Deputy Director General of Meteorology S. Balachandran says that various factors including strong westerly winds, low level troughs and circulation and wind instability have contributed to the incessant rains in the state. Although most of the districts have recorded more rainfall this southwest monsoon, it has occurred in different periods and not in one go.

“We cannot attribute climate change to any single monsoon or individual event. It requires analysis of data over a large period of time,” he explains the reason.

Meteorologists have noted that the state has experienced several episodes of good rains as the Monsoon remained active or even vigorous, bringing in more than four times the average rainfall, which is somewhat unusual for the season.

Senior meteorologist YEA Raj says that several years ago the southwest monsoon performed well across the country as well as in Tamil Nadu in 2022. Rain deficiency can also be met in Kanyakumari. Places like Chennai have seen an increase of 10%-15% in southwest monsoon rainfall over the past two decades. “A good southwest monsoon over Tamil Nadu often may not correlate well with the upcoming northeast monsoon. Tamil Nadu has been marginally deficient in the north-east monsoon during years of abundant south-west monsoon. But there is no conclusive evidence,” he added.

(With inputs from Deepa H. Ramakrishnan in Chennai, L. Srikrishna in Madurai, S. Ganesan in Tiruchi, M. Sabri in Salem and SP Saravanan in Erode.)