The Hindu : Kerala / Thiruvananthapuram News : Study finds imbalance in groundwater availability

Online edition of India's National Newspaper
Saturday, Oct 22, 2005

Kerala

Kerala - Thiruvananthapuram

Study finds imbalance in groundwater availability

T. Nandakumar

Fifty blocks have been included in unsafe category

Thiruvananthapuram: An increased demand and unregulated exploitation are threatening to accelerate depletion of groundwater resources in Kerala, according to a joint survey conducted by the Central Groundwater Board and the State Groundwater Department.

The study reveals a heavy imbalance in the availability of groundwater resources in the State over the past five years, with one-third of the development blocks reporting higher exploitation. There has been a spurt in groundwater extraction during the last decade. While all the blocks were in the safe category in 1992, a computation in 1999 revealed overexploitation in three blocks — six each were classified as critical and semi-critical.

Fifty blocks have moved into the unsafe category in the latest assessment, which used a network of monitoring wells to measure the pre- and post-monsoon water levels in the blocks. Five blocks were classified as overexploited, 15 as critical and 30 as semi-critical. This indicates that groundwater extraction in the State is showing an increasing trend, warranting a systematic and planned response through regulation, artificial recharge and conservation.

Kasaragod on top

The data released by the survey reveal that Kasaragod district taps 79.07 per cent of the groundwater reserves, the highest rate of exploitation in Kerala. Thiruvananthapuram comes second with 66.82 per cent and Wayanad the last with 24.58 per cent. Of the 151 blocks surveyed, 101 fall in the safe category. The survey has recommended restrictions on groundwater development in the unsafe blocks.

Athiyannoor in Thiruvananthapuram tops the list of blocks with overexploited resources, followed by Kozhikode, Kasaragod, Chittoor in Palakkad and Kodungalloor in Thrissur. Chiryankeezh block in Thiruvananthapuram, the most over-exploited region in the 1999 assessment, has moved down to the critical position, occupying the fifth place. Parassala comes next.

All the blocks in Pathanamthitta, Alappuzha and Kottayam districts are in the safe category. Sixteen blocks show a falling trend in groundwater extraction, indicating a lesser stage of development.

At a meeting of the estimation committee, representatives from the Agriculture Department expressed concern over the conversion of paddy fields for non-agricultural use and its impact on groundwater recharge. Between 1985 and 2005, the extent of paddy fields in Kerala had shrunk from 8-lakh hectares to 2.7-lakh hectares, they said.

Four-million wells

The number of open wells in the State is estimated at four million, roughly one well for every eight to 10 persons. Reliance on well water is showing an increasing trend because piped water at the national benchmark rate of 40 litres per capita a day is available in only about 25 per cent of the panchayat wards.

The survey shows that Kerala extracts 46.88 per cent of the net annual groundwater availability of 6,229.55 MCM (million cubic metres). Palakkad district has the highest availability of 750.33 MCM, while Idukki has the lowest of 246.32 MCM. Some of the blocks in the foothills or high ranges, such as Pathanapuram and Anchal in Kollam district, Attapady in Palakkad and Sultan Bathery in Wayanad, have shown a sharp decline in water level despite low extraction.

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