After a relentless monsoon in Himachal Pradesh brought the hill State to its knees this year by causing immense damage to life and property, separate interim government reports suggest that deforestation, ill-planned construction activities, illegal mining along the riverbeds coupled with climate change were a few reasons responsible for the natural calamity in the State.
During this year’s monsoon season, the State witnessed unprecedented damage as heavy rains triggered several incidents of cloud bursts, flash floods, and landslides. The State saw major losses in two different spells of monsoon depressions — the first was between July 9-11 when the monsoon depression coincided with that of a Western Disturbance, and the second spell during August 13-16, wherein, the continuous and heavy precipitation resulted in loss of human lives and property, especially in Shimla — the state’s capital.
‘Construction on debris cover a key reason’
A preliminary report of a multi-expert committee that was set up to assess the cause and impact of the damage that occurred in and around Shimla, revealed that deposition of thick debris on fragile slopes and construction on these debris cover, unplanned drainage system, decreasing binding force of trees amid relentless rain were among major reasons for the damage.
The committee included members from Himachal Pradesh Council For Science, Technology, & Environment (HIMCSOTE); Geology wing of the Industries Department; Public Works Department and Shimla Municipal Corporation.
The report pointed out that the Himalayas’ hill slopes are fragile by virtue of their origin, and over a period of time, these slopes are characterised by thick debris cover in the form of overburden overlying the metasediments at varying depths by virtue of erosion, deforestation, and other ill-planned construction activities, and the changing land use patterns have resulted in the slopes being highly fragile.
“Most of the events that took place during the current monsoon season in Shimla may be due to the thick debris cover, as observed in most of the cases, which resulted in slope failure by virtue of the over-saturation of the unconsolidated subsurface material supporting these slopes,” said the report.
Also, over a period of time, the expansion in Shimla town has resulted in the development of unplanned drainage systems, and their open disposal on the slopes has further contributed to making them more unstable, it added.
‘Felling deodar trees loosens soil along slopes’
The report said the uprooting of the ‘deodar’ (cedar) trees from the almost vertical slopes during heavy precipitation has also resulted in the failure of the slopes supporting thick soil cover or debris cover, leading to debris flow in most of the cases in the recent disaster.
The report also points out that considerable expansion has been seen in Shimla, leading to unplanned urbanisation on these fragile hill slopes, which is another major cause of concern in the recent disaster. “The slopes that support the built-up environment on the debris cover were unable to withstand the heavy rains, which caused slope failure and collapsing of the structure along the debris flow path,” it said.
According to another multi-expert committee report regarding the natural disaster, apart from the effects of climate change, the unscientific and illegal mining along the riverbeds was responsible for the recent natural calamity in the State.
This panel included members from the Department of Environment, Science, Technology and Climate; Geology wing of Industries Department among others.
In Beas river basin
The report said that out of 131 stone crushers set up in the Beas river basin, 68 did not have the necessary permission, and only 50 operators were found to have valid permits. Due to excessive muck dumping in the Beas river and on its banks, the flash floods caused enormous damage to life and both public and private property, said the report, adding that the environmental balance of the river basin is under great pressure, which needs to be studied scientifically.
The monsoon that started on June 24 this year in Himachal Pradesh, withdrew from the hill State with a delay of 12 days from its normal date of departure, i.e. September 24, and saw 21% excess monsoon rainfall this year, according to the India Meteorological Department (IMD) at Shimla.
