The Hindu : Sand-mining poses threat to Vellayani lake

Online edition of India's National Newspaper
Tuesday, Jul 08, 2003

Southern States

Southern States - Kerala-Thiruvananthapuram

Sand-mining poses threat to Vellayani lake

By T. Nandakumar

THIRUVANANTHAPURAM July 7. Ravaged by pollution and land reclamation, the Vellayani freshwater lake here is facing a fresh threat to its existence from illegal extraction of sand in the fallow paddy fields along its periphery.

Truckloads of sand are being removed daily from the vast lowland fields that were reclaimed from the lake by local farmers for paddy cultivation. Scientists warn that sand extraction from the fields would destroy the aquifer layer which helps retain the water table in the lake. They fear that this would in turn affect the recharge and freshwater capacity of the lake and also lower the groundwater table in the region.

Experts feel that the Government has to step in and check the sand-mining if the lake is to be maintained as a freshwater source. The Kerala Water Authority is reportedly drawing up a scheme to tap the lake for water supply to the five surrounding panchayats.

Vellayani is one of the three rainfed freshwater lakes in Kerala, the other two being Sasthamcotta lake in Kollam and Pookkode lake in Wayanad. The lake, which was spread over 750 hectares in 1926, has undergone an alarming rate of depletion in area, now covering hardly 450 hectares.

The lake was a tourist resort during the erstwhile Travancore era. Till 1953, it was used only to grow lotus flowers for the Sri Padmanabha Swamy temple. The `Grow more Food' programme launched by the Government in the early 1950s had led to the reclamation of vast areas for cultivation.

Bunds were constructed along long stretches to carve up the water body and facilitate easy drainage. The lake was dewatered twice annually for paddy cultivation by the 500-odd farmers.

Replenished by 64 rivulets, the Vellayani lake is about a metre above sea level, permitting easy dewatering through the Madhupalam spillway, near Thiruvallam, which empties into the Karamana river. The annual dewatering had led to severe ground water depletion. The five surrounding panchayats - Thiruvallam, Kalliyoor, Venganoor, Nemom and Kovalam - go dry during summer forcing the Government to spend a huge sum to reach water in mobile tankers.

Alternately, during the monsoon, the same areas are inundated, again forcing the Government to shell out lakhs of rupees as compensation to the flood-hit.

Over the years, as local farmers gave up paddy cultivation citing heavy loss, the fields were left fallow.

The Kerala Agricultural University, which had a sizeable area under cultivation, also gave up the unremunerative venture. The Head of the Resource Analysis Division at the Centre for Earth Science Studies, K. Soman, says, "Having been part of the lake, the fields retain a lower layer of sand caused by sedimentation. Removal of this layer is bound to affect the water table in the region.

The resultant decrease in hydraulic pressure will also lead to salinity intrusion beyond the spillway."

Local people say that the arrack lobby had shifted its operation to illegal sand quarrying, which is more remunerative and less risky. They allege that Revenue authorities and police are turning a blind eye to the issu,e which threatens to upset the fragile ecological balance of the region.

Unauthorised removal of laterite soil from the hills in the neighbouring Thiruvallam is another factor that has impacted on the lake and its environs. An Environment Impact Assessment by the CESS had pointed out that these operations drastically change not only the `wetland landscape' but also its ecology and habitat characteristics.

In 1992, the Assembly Committee on Environment had reported about the dangers to the lake and called for a coordinated effort to preserve it but the Government has been dragging its feet on the proposals.

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