• NSDMA Report of Terrain Stability Study of Kohima Town released
• Rapid urbanization, haphazard developments had deteriorated diversely the stability of the terrain
Our Correspondent
Kohima | April 18
Kohima town has been experiencing rapid urbanization and haphazard developments with little planning and such activities had deteriorated diversely the stability of the terrain.
This requires systematic and comprehensive assessment of factors promoting instability such as topography, lithology, geological structures, hydrology, land use and land cover, soils, rainfall and anthropogenic activities, which collectively causes slope instability, according to a report of Terrain Stability Study of Kohima Town by Nagaland State Disaster Management Authority (NSDMA).
The field study shows that the major triggering factors of instability are anthropogenic activity and excessive rainfall received during the monsoon. It stated that the overloading of slopes or removal of slope support by human interference is a prime concern for slope failure in many areas.
“Thus, keeping in view the vulnerability of landslide and seismic activities, proper planning and regulation with strict enforcement of building byelaw would be helpful for planners and administrators to visualize the concept of safety structures and for safer habitant,” the report stated.
Terrain instability caused by landslide, subsidence etc in the state capital Kohima were mostly observed to be occurring within settlement areas, induced naturally or by anthropogenic activities, the report stated.
Some observations made in the report on the instability of Kohima were construction of roads and buildings without adequate slope structure; inadequate surface and sub-surface drainage in colonies /wards of Kohima town and random obstruction of drainages, poor maintenance of natural drainages, random erection of buildings without site investigation in previous landslide areas and without following proper technical specifications, no proper building/infrastructure development code for regulation, random increase of overhead load pressure (storied buildings) in steep slope etc.
Nagaland Chief Secretary, Pankaj Kumar who released the report in book format on Monday said the study is the result of an investigation carried out by NSDMA during 2014-15 to determine the factors responsible for terrain instability and to map stability zones and hazard zones on GIS platform.
In the foreword of the report, the Chief Secretary pointed out that “Kohima, the state capital, is geologically unstable and vulnerable to disasters such as landslide and earthquake.” He said the report marks a “milestone in the journey in preparing Kohima town for taking effective measures against vulnerability to disasters.”
Maintaining that the study enables identification of vulnerable zones for land use planning, design early warning systems, and initiate mitigation measures in unstable zones or landslide prone areas, the Chief Secretary noted that the report would be useful for identifying sustainable areas for development in future and taking steps to reduce vulnerability of areas developed.
He was also hopeful that the study report would help in enhancing “our preparedness to counter hazards by paving the way for informed and effective decision making at micro and macro levels for developmental and regulatory activities in the state.”
Kekhriezavi Lea, geologist at NSDMA, Home Department said terrain stability study of Kohima town was carried out within the constraints of slope pattern, geo-factors, anthropogenic activities land-use/land cover and hydrological conditions. Inherent adverse geological conditions and ecosystem of the hilly terrain cause instability of the area, he said.
The geologist said the report would be helpful for planners and regulators for planning purposes in various developmental activities in the state capital. It would also help in dovetailing building codes with the substandard man-made and natural instability of the terrain for mitigating systematically the natural hazards pursuant to the “react-to-known” hazard principle, he added.
