Saline intrusion threatens survival of Kerala’s kole fields

Saline intrusion due to improper management of regulators threatens survival of kole fields, a highly productive wetland system in 13,612 hectares in Thrissur and Malappuram districts.

Updated - August 18, 2023 10:51 am IST

Published - August 17, 2023 09:09 pm IST

The remains of a temporary mud bund which was built last season on the mouth of the Enamavu regulator.

The remains of a temporary mud bund which was built last season on the mouth of the Enamavu regulator. | Photo Credit: K.K. NAJEEB

Staring at his paddy field filled with weeds and bushes, Goerge J. Ukken, a septuagenarian farmer at Thanneerkayal, laments: “I am not going to cultivate paddy in these fields anymore.” 

Thannerkayal forms part of the kole fields, located in the northwest stretch of the Vembanad-kole wetland ecosystem, a Ramsar Site spread over 13,612 hectares in Thrissur and Malappuram districts. 

“I could not harvest even a spike of paddy from the 25-acre area where I cultivated paddy last season. Saline water intrusion destroyed the crops along the entire stretch, wasting my efforts and pushing me into debt trap,” cries Ukken, who incurred a loss of ₹15 lakh last season alone.

He raised the money for cultivation taking a loan from a nearby cooperative bank. And his case reflects the plight of the 152 farmers of the Thanneerkayal polder, a stretch of paddyland spread over 67.07 hectare in Venkitangu panchayat. 

“When approached for compensation, authorities said the crop damage occurred due to my negligence. Crop damage due to saltwater incursion does not come under insurance coverage,” says Ukken, looking glum and at his wit’s end. 

The situation is no different in the Manaloorthazham paddy cluster with 284 hectares in Manalur grama panchayat. The farmers in the cluster suffered a loss of ₹2.81 crore in terms of paddy alone in the past two seasons. This is apart from the loss of paddy straw and other interim crops. 

Saline intrusion due to improper management of regulators meant to prevent its occurrence threatens the survival of the fragile ecology of the kole fields. The Thrissur-Ponnani kole fields are known for their bumper yield and contribute substantially to the rice requirement of Kerala.

The fields remain submerged for almost six months a year when the area resembles a vast bed of water. Extending from the Chalakudy river in the south to the Bharathapuzha river on the north, the kole fields come in the Central Asian Flyway of migratory birds.

The Enamavu regulator was built in 1956-57 to function as a barrier against saltwater intrusion.

The Enamavu regulator was built in 1956-57 to function as a barrier against saltwater intrusion. | Photo Credit: K.K. NAJEEB

Lying 0.5 to 2.5 metre below the sea level, the threat of saline intrusion has been perennial for the kole fields. Realising the ecological and economic importance of the wetland system, an automatic regulator called Enamavu lock was built in 1956-57 with the technologies available at that time to function as a barrier against saltwater intrusion. 

“The regulator, which operated with motors, had saline monitors too,” recalls P. Parameswarn, an elderly farmer and president of the Enamavu-Mullassery Kole Farmers’ Samiti.

A bus ran into the regulator’s electrical system in 1987 damaging its operation. Its motors, taken away for repairs, never returned. The regulator has been functioning manually ever since, he says. Two other regulators were commissioned at Idianchira and Munayam in 1998 with the same objective.

Over the years, all three regulators developed leakage and became defunct. Most of their shutters, submerged in saltwater, rusted and got stuck due to improper management and lack of timely service, say farmers in the area. 

A regulator has two functions in the kole system. During rains, it allows draining of floodwater collected in the kole fields to the backwaters through Canolly Canal and further to the sea through the Chettuva Azhi. In other seasons, it blocks the entry of saltwater from the sea to the kole fields, which are below the sea level.

The Irrigation department now manages the system by constructing temporary mud bunds every year in front of the mouth of the regulators. But they are not built in time to check saline water intrusion, say the farmers.

“They are not concerned about farmers’ issues. They build and break each year without any planning and without considering the changes in rainfall,” says Parameswaran. 

“The farmers of Venkitangu and Mullassery panchayats, the most productive panchayats in the kole fields, suffered a cumulative loss of ₹12.57 crore (4,424 tonnes of paddy) in the past two years alone. There are 3,024 farmers in the 19 paddy polders spread over 1,332.4 hectare in the two panchayats,” says K.K. Aneesh Kumar, who conducted a study on the impact of saline intrusion in the two panchayats. 

The kole fields were three times more productive compared to the paddy lands elsewhere in Kerala, thanks to the yield from the panchayats of Mullassery and Venkitangu, which used to yield 6.5 tonnes of rice a hectare. It has now plunged to 1.79 to 2.7 tonnes in the past two years, says Kumar. 

“Salinity has degraded the quality of our paddy,” laments E.D. Sunny of the North Mathukkara paddy polder. “Buyers would vie with one another to procure the rice, popularly known as kanji rice, we produced. Now the weight of the grain has dropped. The tonnage does not match with the volume,” he says. 

Even though water drains out to the sea, salt gets deposited on the canal beds. When the canals were desilted recently, salt-deposited soil was piled up on either side of the canal. But the rains brought it all back into the fields. This affected the paddy badly in many areas, including in our paddy cluster at Mathukkara, Sunny adds.

According to farmers, the saline tolerance level of paddy is up to 2 parts per thousand (ppt). But the salinity of water in the kole fields in April this year was about 20 ppt, they say.

“Worse, in most cases, the farmers get to know about the increase in salinity only when the crops start wilting. By that time, high quantities of saline water may have entered the fields,” says Kumar. 

The kole fields are not only the source of livelihood for farmers but also the lifeline of Thrissur and Malappuram districts, says E.J. James, former Director of the Centre for Water Resources Development and Management and member on the governing body of the Wetland International South Asia. 

“The fields protect Thrissur city and Ponnani town from flooding by receiving the entire floodwater during rains. These fields that remain submerged for many months in a year recharge the water table in the entire area,” says Dr. James.

It is estimated that about 233.74 m3 water is contained in the vast stretch of kole lands, which is more than the storage capacity of the Chimmony and Peechi dams – both in Thrissur district – counted together. 

The leakage in the regulators also lowers the fertility of the fields. Floodwater that enters the kole fields through the Kechery and Karuvannur rivers brings fertile soil along with it, which gets sedimented in the fields and canals. That is one reason why fertilizer use has been traditionally low in the kole fields. The word kole in Malayalam suggests bumper yield, which ensures high return. 

A season of farming begins with dewatering of the kole fields. Excess water is pumped into the network of main and cross canals that punctuate the fields. This water is meant to be used later in farming during the dry season. The leakage in the regulators allows this mineral-rich water to get drained to the sea. 

“Protecting farming in the kole fields has great ecological importance. The kole fields are a habitat for 200-odd birds. This apart, a large number of migratory birds visit the fields every year. The vast stretch of the fields is also home to fish varieties. Once the farming activity stopped, the biodiversity of this unique ecosystem will perish,” says Dr. James. 

It will lower the groundwater level and lead to saline intrusion in the waterbodies in the area. “Farming should be sustainable and profitable to attract the next generation of farming enthusiasts. It is the responsibility of the government and society to protect this farming culture. Renovation of the three regulators with most modern technologies is the need of the hour,” he says.

Tonnes of soil scooped out from the hills are dumped in the lake to make temporary bunds every year.  This gets washed away by rainwater and this ecological crime is repeated annually, he reasons why the regulator work should get priority.

At present, water released from the Chimmony reservoir for irrigation is used to flush out  saline water to the sea. Around 30% of the water released from Chimmony is thus wasted, he says.

A recent convention of kole farmers came out with a resolution called the ‘Mullassery Declaration’ in which the call to renovate the three faulty regulators topped the charter of demands. They urged the government to use Artificial Intelligence to aid the automatic functioning of the saline sensors. 

The farmers also demanded insurance coverage, compensation package, and a single window system for service delivery. 

Meanwhile, Shibu Tharakkal, Assistant Engineer, Irrigation department, Enamakkal, says that the tendering process for the renovation of regulators is expected to start soon. 

“Earlier, a company based in Pune showed interest in renovation. But its bid amount was much higher than the estimate. So, the tender got cancelled. Now a revised estimate has been submitted. The department is waiting for the revised administrative sanction,” he says.

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