The Kerala Water Authority (KWA) has sought to allay fears of muddy water in the Periyar affecting the drinking water supply to lakhs of Kochiites from its Aluva pumping station.

Anitha C.O., assistant executive engineer of the head works section at Aluva, rejected reports that the turbidity level in the river had turned alarming. The maximum level was only 22 ntu (nephelometric turbidity units) on Wednesday. The turbidity level on Tuesday was 25 ntu. The level was brought down to the prescribed limits by adding water treatment chemicals in the water supply system to improve the quality.

Ms. Anitha said that water started getting muddier owing to the heavy rain. “We could ensure uninterrupted water supply even when the turbidity level went up to 100 ntu a month ago,” she said.

KWA officials said that removal of silt at the Kallarkutty and Bhoothathankettu dams would result in the discolouration of the Periyar in the coming days. Usually, the heavy discharge triggers a colour change in the river and water starts getting muddier, they said.

Continuous monitoring of water levels is progressing to check the water quality. Alum and lime are also used to bring the water quality level within acceptable limits. Efforts are also on to keep pH (the pH of a solution indicates whether it is acidic or alkaline) and turbidity levels within the permissible limits.

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