Disasters in the Uttarakhand Himalayan region and other Himalayan States
Himalayas, as a region, have always been susceptible to disaster, due to the neo-tectonic mountain-building process, like earthquakes, landslides, floods, etc. The spread of reckless developmental activities has transformed many natural disasters into man-made events. Such calamities play a grave negative socio-economic role on the national economy and exert additional pressure on an already strained national economy.
It is important to discuss the origin of the Himalayan Mountains for understanding the natural seismicity in the Himalayas. Around 45 million years (during the Eocene period on Geological Time Scale), India collided with Eurasia. This was due to the continued northward migration of India. Since then, India has penetrated some 2000 km into Asia leading to the creation of Himalayan Mountain Range and this process is still in continuation. In this process, the Himalayan plate is undergoing beneath the Eurasian plate.
Thus, the Himalayan Mountains are the only ‘living’ mountains in the world as the plate tectonic activities churning within the Himalayas are leading to increase in its height. This internal turbulence within the Himalayas is solely responsible for their active seismic nature as corroborated by a large number of earthquakes traversing the entire belt from time to time, taking a heavy toll of life and property. Overall, more than ninety percent of the earthquakes occurring in India fall within the Himalayan mountain zone and its foothills. Scientifically, it has been experimentally shown that the seismicity creeps in an area through pre-existing zones of weakness and the neo-tectonic activities of Himalayas make it a zone of weakness. In last ten years, two major earthquakes have occurred in Uttaranchal namely the Uttarkashi earthquake (1991) and the Chamoli earthquake (1999).
It should be noted that the damages in the event of an earthquake primarily result from the unplanned developmental activities in seismicity-prone areas, which increase the casualties of life and loss of property manifold. Therefore special attention should be paid in undertaking major developmental activities like human settlements, urbanization, road building, laying of railway tracks etc. Japan, seismically one of the most vulnerable countries, has successfully shown that the damages accruing from an earthquake, even with a higher magnitude of 7 on Richter Scale, can be minimized by adopting an integrated approach of generating awareness, building earthquake resistant structures, always keeping the level of preparedness at a higher level, and preparing and regular updating of elaborate disaster management plan in case of an eventuality.
Landslides are defined as the mass movement of rocks, debris or earth down a slope dislodging earthen material on its way. Often they are associated with other calamities like earthquake, floods or volcanoes, involving movement of earth. Prolonged rainfall also causes heavy landslides, especially in mountain areas devoid of vegetation cover, blocking the flow of river. These river blocks, if and when they burst, can cause havoc to the settlements downstream. Landslides are common occurrence in the hilly states of India . For example, 380 people were killed when massive landslides washed away the whole village Malpa, Uttarakhand in 1998. In recent years a number of landslides occurred during the monsoon season, triggered by the heavy rains. This led to the blockade of roads in most parts of the state, like, Shimla-Kalka road (Himachal-Haryana link road), the Hindustan Tibet Highway,and other similar events. Incidents of landslides were also reported from Solan, Sirmaur, Bilaspur, Hamirpur and Palampur.
In recent times extreme rainfall events as cloudbursts are dominant phenomenon trigger large scale mass movement and flash floods in the Himalayan region. Cloudburst is a natural and common phenomenon in the Himalaya, especially in Garhwal and Kumaon region of uttarakhand. Cloudburst and associated disaster affect thousands of people every year and cause loss of life, property, livelihood, infrastructure and environment. Almost every year several parts of Uttarakhand Himalaya experience cloudburst and associated hazards. Cloudburst during August 1998 at Ukhimath (Rudraprayag) and Malpa (Pithoragarh), August 2001 at Phata (Rudraprayag), August 2002 at Burakedar (Tehri), August, 2012 in Asi Ganga (Uttarkashi), September, 2012 at Ukhimath (Rudraprayag) and June 2013 at Kedarnath (Rudraprayag) are some of the examples of recent cloudburst incidences associated with flash floods and landslides in Uttarakhand Himalaya. The Cloudburst is a natural phenomenon that generally occurs during monsoon period over many regions of the Himalaya. Generally, cloudburst refers to particularly heavy precipitation in a short period of time over limited geographical area. It is often defined as more than 100 mm/hour rainfall within a limited geographical area of a few square kilometres. The landforms of the Uttarakhand Himalaya located above 1200 meter altitude are extremely sensitive for the cloudburst induced landslides during monsoon season.
Cloudburst incidences over many areas of Himalaya often go unnoticed due to the absence of meteorological observatories. Many a times these come to notice only when these are accompanied by losses and casualties. In the absence of losses these can only be identified on the basis of inundation occurring along streams. Mostly upper reach of first order and second order drainages (seasonal streams) have been observed to be overwhelmed by debris flow during these incidences. Slope failures and bank erosion are common during this phenomenon which result sedimentation and sometimes block the river course, turn them into big lake and create flood condition.
Considering extreme rainfall events in Uttarakhand Himalaya, it is suggested that instead of valleys and along abandoned channel of drains people should inhabit on the hard rock or firm ground of slopes for safety reasons. At locations where ground fissures have developed and subsidence has taken place appropriate measures are required for checking infiltration of rainwater as well as surface water. This should precede implementation of permanent treatment measures. People living around these slopes should remain vigilant, particularly during the monsoon period and any physical change in the slope should immediately brought into the notice of authorities. On the basis of information collected from the local people, strong wind and lightning are very common during cloudburst. Even though locals consider it to be a cloudburst event it is hard either to accept or reject their assertion in absence of authentic meteorological data from the proximity of slope failure incidences.
Indiscriminate and unscientific construction should be banned especially in landslide affected areas. Besides this safe disposal of rainwater needs to be given due importance. Both surface and subsurface drainage measures should therefore be planned and executed. For this drain pipes could be provided on debris slope. The planned drainage network should be stepped and wide enough to accommodate heavy downpour events. Increasing anthropogenic activities, venturing in unsafe areas due to limited land availability and heavy localized precipitation, these are continuously increasing the landslide vulnerability in Didihat town as well as hilly terrain of Uttarakhand. In case indiscriminate and unscientific construction could not be regulated all mitigation and treatment measures would remain a mere formality and would be of little use. The bioengineering technology can be successfully implemented by using specific and local vegetation along with engineering measures to reduce instability and soil erosion. Although it is difficult to forecast cloudburst events, dense network of rain gauges particularly in the areas identified as being vulnerable to cloudburst is required for better understanding of this phenomenon. Accurate measurement of such events and studies based on different aspects of geology, geomorphology and climatology could help in developing a cloudburst forecasting model. Such studies would at the same time result in efficient landslide risk mitigation. At the same time the awareness about the extreme precipitation events and associated disasters among the dwellers of the area is needed.
Avalanches are common in Himalayan region with altitude more than 3500 meters and where slope is generally more than 30 degree. North facing slopes are known to have avalanches in winter whereas south facing slopes usually get them during spring time. In recent past many incidences of avalanches have been observed in higher reaches of the state like Gomukh Glacier, Hemkunt Sahib, Ghastoli and Kalindi–Badrinath track.
A flood caused by heavy or excessive rainfall in a short period of time, Flash floods are usually characterized by raging torrents after heavy rains that rip through river beds, urban streets, or mountain canyons sweeping everything before them. They can occur within minutes or a few hours of excessive rainfall. They can also occur even if no rain has fallen, for instance after a levee or dam has failed, or after a sudden release of water by a debris or ice jam. The intensity of the rainfall, the location and distribution of the rainfall, the land use and topography, vegetation types and growth/density, soil type, and soil water-content all determine just how quickly the Flash Flooding may occur, and influence where it may occur.
The youngest mountain ranges of the Himalayas have been assessed as the most vulnerable stretches of world with regard to forest fires. In 1999, forest-fires in the hills of Uttaranchal destroyed more than 3,75,000 hectares of forest.
In terms of the incidences of forest fires, 2016 was particularly bad. According to data from the environment ministry, a total of 18,451 incidents of forest fires were reported from across the country in 2013, compared with 19,054 in 2014 and 15,937 in 2015.
Uttarakhand Rehabilitation and Reconstruction Authority
Uttarakhand Reconstruction and Rehabilitation Authority was constituted and entrusted with the task of rehabilitation of the disaster-affected persons and reconstruction of affected areas after cloudburst and flashflood disaster in 2013.The statutory body,is chaired by the Chief Minister,takes into account safeguards required in view of challenges to be faced 100 years from now.
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