High rate of siltation a threat to Nainital Lake, says scientist
Since 1881, level of silt in the lake has increased by 1.8 m, quite high compared to other water bodies in regiondehradun Updated: Jul 20, 2016 21:18 IST
Silt and debris washing up in Nainital Lake – a mile-long natural freshwater body fringed by willows – could soon choke the lake to death, a scientist has warned.
Drinking water for Nainital is sourced indirectly through tube wells dug in the vicinity of the lake. The fall in the carrying capacity of the lake affects water supply to the city as it did this summer – the water level had gone down by around 18-20 feet, leading to water rationing.
Professor BS Kotlia, a research scientist in climate change and palaeontology at Kumaon University studying silting in Nainital lake, said the silt accumulation rate of the lake beats the natural pace witnessed in other such water bodies by an alarming range. “We have conducted geological studies in other lake of the region and found lesser silting. The deposition of 1.8 metres of silt in a time span of 135 years is a big issue as such silting should have taken place in a time frame of thousands of years,” said Kotlia.
He said the sedimentation for other lakes is 50 cm per thousand years.
The lake witnessed massive silting in 1881, when a landslide in Mallital, the north-end of the lake, killed around 151 people and dumped large volumes of silt into the lake. Since 1881, the level of silt in Nainital Lake has increased by 1.8 metres, which is clogging the lake, said Kotlia.
Kotlia took samples of lake soil by drilling, and estimated it to be around 50,000 years old.
Nainital Lake is one of the four main lakes in the Kumaon hills – Bhimtal, Naukuchiyatal and , Sattal being the other three.
“We have also conducted geological studies in other lake of the region and found lesser silting,” he said.
Kotlia said unscientific constructions at the lakeside must be checked. “A lot of buildings have been built here in the city without any planning for waste management etc, which might have taken its toll on the lake.”
The rains that lashed the district in the last five days had not replenished the lake to the desired levels, said CM Shah, the project manager of Nainital Lake Development Authority. Shah said commercial constructions were banned in Nainital. “People have to take LDA permission for residential construction and this has been done to check unplanned construction.”