Tamil Nadu: Rivers
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Seawater enters up to 20km upstream
Yogesh Kabirdoss & D Vincent Arockiaraj, Tamil Nadu rivers in reverse gear, Sep 9, 2017: The Times of India
The deteriorating quality of waters in the rivers of Tamil Nadu
Threats to the six main rivers of Tamil Nadu
Seawater Incursion, Up To 20km Upstream, Is Turning Farmland Saline In Cauvery Delta
Follow the river and you will find the sea. Those who follow the Cauvery in Tamil Nadu, how ever, will be disappointed, as the lifeline of ag riculture on some 88,000sqkm across Karnataka, Andhra Pradesh, Tamil Nadu and Puducherry , is dry hundreds of kilometres before it meets the Bay of Bengal. And the sea, as if in search of the river, is making incursions inland--with disastrous results.
Seawater incursionup to 20km upstream in parts of the Cauvery delta which includes Thanjavur, the rice bowl of TNis ruining soil fertility in Tiruvarur and Nagapattinam districts of the state.S Janakarajan of Madras Institute of Development Studies says groundwater in Nagapattinam, at the tail-end of the Cauvery , is 100% saline and up to 60% in Tiruvarur.
“The incursion has been rapid in the past few years. It has also affected the soil in Nagapattinam.If water doesn't flow in In partnership with our rivers, our food security will be threatened,“ he says.
This salinity has rendered 2.32 lakh hectares of farmland in Cuddalore, Nagapattinam and Thanjavur districts unsuitable for cultivation, says S Dhanapalan, president of the Cauvery Delta Farmers' Association. “ About 57% of this is completely affected by salinity and cultivation in the rest is dependent on rain,“ he added.
In such a situation, many growers have re verted to traditional va rieties of paddy that can be cultivated in saline water, says `Nel' R Jayar aman (Nel means paddy).
“About 37,000 farmers across the state grow these varieties. Of them, about 5,000 are from coastal villages in Cud dalore, Nagapattinam and Tiruvarur,“ he said.
While farmers get about 2,100 kg of paddy worth Rs 24,000 per acre by cultivating hybrid seeds, traditional varieties yield 33% less, but fetch up to Rs 30,000 per acre in the market. With robust traditional varieties, farmers can afford to spend less on fertilizers, pesticides and weeding.
Besides, seawater incursion into Kollidam river, a branch of Cauvery , river, a branch of Cauvery , has also contaminated groundwater. As many as 150 villages, including Chidambaram and Bhuvanagiri, along the coastal belt are struggling for drinking water, says P Vinayagamoorthi, president of Kollidam, Keelanai Farmers' Association. The situation improves a bit occasionally , when Kollidam is in spate, he added. Former chief minister J Jayalalithaa had in August 2014 announced construction of a barrage across Kollidam to stop seawater incursion. Unless the project is implemented, people will continue to suffer, Vinayagamoorthi said adding that the government should also put an end to excessive extraction of groundwater wherever it is potable.
Besides sea incursion, excessive use of chemicals and fertilizers in the catchment areas is also affecting the tail-end regions of the river. “Much of the fertilizers and pesticides used in the coffee estates of Kodagu Hills and Hassan district in Karnataka end up as deposits in the tail-end of the Cauvery and its branches,“ says S Dhanapalan.
Unless a series of measures are taken like building check dams and barrages and renovating drainage channels, farmers will have to permanently give up agriculture, he added.