Indiscriminate sand mining creates water shortage in Kerala

Kochi, May 4 Drinking water shortage in several parts of Kerala, especially in the high and midland areas of many districts, has become so acute that the inhabitants have to depend on water supply by private operators for whom it has turned out to be a lucrative business.The sharp fall in the ground water table, even in the embankments of major rivers like Pampa, Manimala, Achankovil etc, following indiscriminate sand mining, has resulted in the wells drying up even in February, environment activists said."Ever increasing human intervention in several major rivers in Kerala in recent years has changed their physical structure in such a way that it might sound the death knell to these rivers, if the authorities continued to remain indifferent," they told Business Line.One of the major victims of these activities is the River Pampa. Sand mining has removed the sand bed, which used to remain as a carpet, exposing the clay soil in several parts.Indiscriminate sand mining during the past two decades has deepened the riverbed by an average three to four metres, while there are points where it has dropped by six metres.Consequently, the water table in the wells in the catchment areas and in the river basins also have fallen sharply to the surface water levels in the rivers, Mr N.K.S. Nair, General Secretary of an NGO, said.Sand mining, check dams across the rivers, separating a large part of the sand bed as an enclosure for other purposes by dividing the river using permanent construction and so on, have been pointed out as reasons for the degradation of the rivers.When the riverbed level falls, the hydraulic gradient increases leading to higher velocity. As a result, immediately after the monsoon the water that flows into the rivers is drained out quickly. Unlike in the past, rivers are filled during the rains but after a few days of dry weather they become skeleton, said Mr Nair, a retired engineer."In the absence of sand no natural retention of water takes place. Sediment deficient flow of 'hungry water' picks up more sediment from the stream below the mining site, furthering the degradation process," he claimed.Thickets have come up at many points in Bharathapuzha and Periyar rivers also, he said.Normal monsoon season in Kerala is from June 1 to November 30 and the State used to receive on an average 3,000 mm of rainfall. Until a decade ago, the water table used to remain at higher levels up to March.But the situation has totally changed now. Immediately after the southwest monsoon, the water level in the rivers falls drastically leading to drought conditions. The wells in the river basin and the catchment areas dry up fast following the drop in underground water table, he pointed out. Environmental degradation is held as the reason for this situation.According to a study of the Kozhikode-based Central Water Research, the water availability by 2050 in the rivers Achankovil, Pampa and Manimala would drop by 459 million cubic metres, 3,537 million cubic metres and 398 cubic metres, respectively. If all these activities were not controlled and regulated by the authorities the water scarcity in the State would acquire serious dimensions in the years to come; this is already experienced in mid and high lands in several districts of the State, they warned.

The Business Line, 5th May 2009