Quantification of geomorphodiversity and its spatial distribution with the flood inundation areas for Assam, India

Assam, located in the Northeast of India, is highly flood-prone, and the erosional and depositional processes highly influence the landforms. The formation and development of landforms are directly related to the geology, geomorphology, drainage basin characteristics, and soil types of the region. In the present study, a remote sensing and GIS-based geomorphodiversity index (GMI) assessment of Assam is performed using three sub-indices: geodiversity, morphometric diversity, and drainage diversity index. Sixty-six potential geomorphosites are identified with their geological, geomorphological, and GMI classes. With the help of a flood inundation map, the inundated area of each GMI class is calculated. According to the result, 27.02%, 10.76%, and 3.7% of the total area of Assam fall under moderate, high, and very high GMI classes, respectively. Barak Valley and Central Assam region exhibit high to very high GMI values. Geology and geomorphology have a strong influence on GMI values. About 22.32%, 28.33%, 37.18%, 38.25%, and 35.37% of areas with low, moderate, high, and very high GMI are inundated, respectively. This study determined that areas having high GMI can increase the geomorphological heritage value of the region and can play a significant role in promoting geotourism with an increase in the scientific, educational, and aesthetic value of geomorphosites. This study can also help the local governing authorities to conduct and implement better management and conservation policies for vulnerable locations.