GIS modeling to investigate environmental change and degradation in Kohima district, North East Hill (NEH) region of India.

Abstract

As a part of the Himalayan mountains, the North East Hill (NEH) region of India is geophysically dynamic and seismotectonically active since its formation about 55 million years ago with a head-on collision of the Indian plate and the Eurasian plate. The region still has been underthrusting at a rate of 4.5-5cm/year causing the reshaping and changing of its geophysical characteristics (geology, geomorphology, relief, slope gradient, drainage system, etc.), whereas anthropogenic activities, particularly shifting cultivation and technological intervention, have caused changes or degradation of the ecological environment (air, land, water, vegetation, crop pattern, climate, wildlife, etc.). Addressing this burning geoecological problem, a geospatial technology-based case study from the Kohima district of Nagaland in the North East Hill region of India is presented here. Through the development and integration of multiple GIS modules, this reconnaissance study suggests that continuous seismic activities (about 27 seismic events/year) along tectonic faults, thrusts, and lithological shear zones have been reshaping and changing the geophysical environment, whereas the ecological environment has been changing or degrading due to decreasing natural landscape and habitats (forest area, water bodies, and shrubs) at an annual rate of 5.91 km2 (0.60%), increasing built-up area, agricultural land, and wasteland at an annual rate of 2.73 km2 (0.28%), 2.69 km2 (0.27%), and 0.49 km2 (0.05%) respectively. Results also suggest that environmental degradation results in accelerated trends of climate change (rising temperature at the rate of 0.13°C/year, decreasing annual rainy days at the rate of 2days/year, decreasing annual rainfall at the rate of 9.55cm/year, mounting climatic zones at the rate of 175m/year) and its adverse impacts (increasing extreme rainfall events at the rate of 3 events/year and causing cloud burst, erosion, landslides, and floods) in the region.