Author(s)

Karamat Ali^1,2*, Roshan M. Bajracharya¹, Bishal Kumar Sitaula³, Nani Raut¹, Hriday Lal Koirala⁴

¹Department of Environmental Sciences and Engineering and Aquatic Ecology Center, Kathmandu University, Kathmandu, Nepal.
²Department of Environmental Sciences, Karakoram International University, Gilgit, Pakistan.
³Department of International Environment and Development Studies (Noragric), Norwegian University of Life Sciences (UMB), Akershus, Norway.
⁴Central Department of Geography, Tribhuvan University, Kirtipur, Nepal.

Watershed morphometric analysis of a basin is key to understand the hydrological processes. The Gilgit river basin is situated in the Hindu Kush and Karakoram Mountains of Pakistan. The provincial capital of Gilgit-Baltistan is located in the lower part of the basin. Morphometric evaluation of the Gilgit river basin was carried out to study its drainage characteristics and overall water resource potential. The entire Gilgit river basin has been divided into six sub-basins to calculate and analyze the selected morphometric parameters. Morphometric parameters have been classified into linear, aerial and relief aspect. Geographic Information System (GIS) provides a viable method to extract and evaluate the characteristic of hydrological response behaviour of the basin. In the present study the utilization of remote sensing data such as Thermal Topography Mission and Global Elevation Model (ASTER-GDEM), Sentinel 2A image, coupled with geological and field data into GIS environment for morphometric analysis of Gilgit Basin. The drainage area of the basin is 13,538 km² and shows a dendritic drainage pattern for all sub-basins. The analysis reveals that drainage network of entire Gilgit river basin constitutes a 7^th order basin. Out of six sub-basins, Gilgit-Gahkuch (B1), Ishkoman (B2) and Phunder (B4) are 6^th order sub-basins. Yasin (B3) and Gupis (B5) are 5^th order sub-basins, while Bagrot (B6) is a 4^th order sub-basin. The Gilgit Basin drainage density value is 0.50 km/km², which indicates a well-drained basin. Morphometric parameters like stream number, order, length, bifurcation ratio, drainage density, stream frequency, elongation ratio, circularity ratio, form factor, relief and relative relief, slope, length of overland flow, ruggedness number, and hypsometric integral are calculated. The results indicate that the entire drainage basin area reflects youthful to early mature stage of the fluvial geomorphic cycle and high potential of stream discharge which is dominated by high relief, rainfall, glacier and snow fed order streams.

Drainage Morphometry, Gilgit Basin, Remote Sensing

Ali, K. , Bajracharya, R. , Sitaula, B. , Raut, N. and Koirala, H. (2017) Morphometric Analysis of Gilgit River Basin in Mountainous Region of Gilgit-Baltistan Province, Northern Pakistan. Journal of Geoscience and Environment Protection, 5, 70-88. doi: 10.4236/gep.2017.57008.