The government has launched a geophysical survey to probe the emergence of sinkholes in Armala VDC of Kaski district from Saturday.
The need of such a survey was proposed by the experts in their report submitted to the government some four months ago, following a month-long research.
The Department of Water Induced Disaster Prevention under the Ministry of Irrigation has assigned Professional Network for Engineering Services (P-NET) to conduct the geophysical survey.
As per the agreement, P-NET will have to submit the survey report to the government by the last week of the current fiscal year.
According to Umesh Bhusal, a member of the team which also comprises geologists and environmentalists, the survey is being conducted to find out what exactly is happening underneath the surface.
“Sinkholes in Armala VDC have been emerging for around six months. However the factors that are causing the sinkholes are yet to be established,” Bhusal said.
“The survey will find out soil and rock formation and flow of water inside the surface of Armala,” added Dr Moti Rijal, associate professor of the Central Department of Geology at Tribhuvan University.
Once the survey is completed, preventive measures can be devised to stop further sinkholes in Armala, he added.
For geophysical survey, 60 electrically charged iron rods are being inserted a meter part in Armala and a wide range of sensing instruments are being used for systematic collection of geophysical data for spatial studies, including the flow of water and formation of rock up to 20 meter beneath the surface.
“The preliminary report will be submitted to the government within the first week of last month for the current fiscal year,” Bhusal added.
More than 160 sinkholes have emerged in Armala since the first one was reported around six months back.
Meanwhile, farmers in Armala are at loss whether to plant paddy crops before the survey is over.
Ram Prasad Parajuli, secretary of Armala Disaster Concern and Construction Cooperation Committee said, “Geophysical survey was our demand. But we are also farmers, and it the harvest season is round the corner. Now we are in dilemma whether to plant paddy for not. If we are to wait till the survey is completed and the report is out, the harvesting season might be over.”
The construction of embankments at Kalikhola near Armala has also started to prevent further sinkholes.
To prevent from further deepening of the river and to stop water flowing inside the survey, stones and aggregates are currently placed in the river, Parajuli informed.
A team of experts deployed to investigate the sinkholes in Armala in December last year had attributed the disaster to rampant human encroachment of the seasonal rivers.
According to experts, the sinkholes will continue to be formed until streams that have been encroached upon are allowed to resume their original course.
The sinkholes were formed after the underground water kept eroding the soil beneath the surface.
Locals in the VDC have encroached on the seasonal rivers and streams to construct houses and grow crops. In the past three years, the Kali River that passed through the VDC has already sunk three meters due to the illegal excavation of stones and gravels from the riverbed .This activity should also be taken under control to stop the sinking of land, according to expert.
Last year the government had formed a seven-member team comprising technicians and geologists to investigate the sinking of lands in Armala.
In 1998, the Department of Mines and Geology along with a German company had said that Pokhara and its nearby regions are vulnerable to catastrophe related to geology. Despite the warning, locals had continued to construct tall buildings and encroach on the seasonal streams and rivers.