Periyar river in Aluva turns dry. Though Kerala got 33% excess rain in three monsoon months, there is a deficiency of 86% in first week of September. (Photo: Prashanth Chandran) Periyar river in Aluva turns dry. Though Kerala got 33% excess rain in three monsoon months, there is a deficiency of 86% in first week of September. (Photo: Prashanth Chandran)

An unusual dry spell coupled with the reported fall in the groundwater level in flood-hit areas of Kerala has emerged as a cause of concern.

IMD, Thiruvananthapuram, director S Sudevan said the state has received hardly any rain since the beginning of this month. Weekly rainfall for the whole of Kerala from August 30 to September 5 was a mere 7.9 mm as against 56 mm, the normal figure during the same period. Although Kerala has got 33 per cent excess rainfall in the three months of monsoon, there is a deficiency of 86 per cent in the first week of September.

“As per our extended forecast, rain would pick up only after September 17. The present dry period is unusual. Due to no rain, the temperature has also increased, mainly in southern parts of the state,’’ said Sudevan.

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The IMD, however, said the dry spell was not limited to Kerala but was spread to most parts of the country, except the north-eastern region and some parts of north India. D Sivananda Pai, head of climate prediction department at IMD, said this dry spell could, in part at least, be attributed to an “evolving El Nino-like condition” in the equatorial Pacific Ocean.

“The El Nino has not reached a maturity stage, but we are seeing some warming in the Pacific Ocean. This is having an indirect impact on the monsoon rainfall over India, as the moisture is being pulled out,” Pai said.

Kerala Groundwater Department director Justine Mohan said the department has come across incidents of fall in groundwater level in flood-affected areas. “We have started collecting data from sample wells of the department for analysing the situation,’’ he said.

Mohan said surface soil is the most important factor that enables groundwater recharge or infiltration of water into the earth. The flood has caused large-scale soil erosion in some places and in such areas, water infiltration would not be at the expected normal level, leading to a dip in groundwater level, he said. However, in areas where soil got deposited in flood, water infiltration would increase, leading to better groundwater storage, he said.

Groundwater department sources in Pathanamthitta said there is an unusual fall in water level in wells in flood-hit areas. The department has received a complaint from one village, where water level in wells have gone down after the flood. The issue is mainly in wells where water has been flushed out as part of cleaning of drinking water sources after the floods. In such wells, water level hasn’t recovered to a level that is expected in the monsoon.

In Ernakulam, another flood-hit region, a similar trend was reported, but officials said a conclusion cannot be arrived at this stage as water level has to be monitored in phases.

Centre for Water Resources Development and Management’s executive director Dr A B Anitha said people have started informing them about the sudden fall in water level in rivers, which were flooded a month back. “We have to study in detail the situation in every river. The flow of water is fast after the flood has cleared all obstacles. In such a situation, the depth may be affected, leading to an impression that water level has come down. Another factor is that regulators in certain rivers have been kept up to drain water after the flood. That would also contribute to the sudden dip in water level. No rain in the last two weeks might be another factor,’’ she said.

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