A study of knickpoint surveys and their likely association with landslides along the Hunza River longitudinal profile

Abstract

Mass wasting and tectonic uplift are the major factors, responsible for reshaping the northern Pakistan that contains the world's most steeply inclined mountainous regions including: Karakoram, Himalayas, and Hindukush Ranges. The role of GIS and remote sensing is inevitable to study the river geomorphology for the identification and evaluation of different mass wasting processes. digital elevation models (DEMs) are frequently used to extract the longitudinal profile of the rivers to identify the knickpoints and their related geomorphic attributes. For this study, ASTER DEM of 30 m spatial resolution satellite data was utilized to perform the geomorphological analysis of the longitudinal profile of the Hunza River in ArcGIS and Matlab environment. The Hunza River channel with having the watershed area of 13571 km 2 , has witnessed a number of historic landslide dams (i.e. Attabad, Ganesh and Boultar glacier, etc.) that blocked the main river channel at multiple sections in different episodes of time. These past landslides presumably preserved in the river channel as knickpoints at their respective locations. In this study, a total of 77 knickpoints were identified along the main stem of the river channel. The spatial locations of the extracted knickpoints and their normalized steepness index (ks) values were compared with the Hunza River landslide inventory map, lithologic contact, tectonic faults and historic landslides data. Furthermore, the likely role of these geomorphic factors was evaluated to ascertain their association with knickpoints formation. The results of this GIS-based geomorphic analysis of the river profile and subsequent field visit of the area revealed that the formation of landslide dams and their subsequent breaching is one of the major trigger factor of knickpoints along the channel. Such studies highlight the benefits of inexpensive remote sensing data and GIS tools to assess the likely role of various geomorphic features in the formation of significant knickpoints along the river profiles on a regional scale.

Improving landslide inventories by combining satellite interferometry and landscape analysis: the case of Sierra Nevada (Southern Spain)

“…Galve et al 2017;Reyes-Carmona et al 2021;Gaidi et al 2021;Cigna and Tapete 2021) as well as the k s and k sn index analysis (e.g. Pánek et al 2007;Walsh et al 2012;De Palézieux et al 2018;Ahmed et al 2019;Gu et al 2021). Nevertheless, the advantages of combining both data sets have not been explored until the present study.…”

“…Knickzones are reflected as clearly higher values than the rest of values along the river profile, which are considered as anomalous values. The successful application of gradient-related indexes to detect landslides has already been proven in several studies (Pánek et al 2007;El Hamdouni et al 2010;Walsh et al 2012;Troiani et al 2014Troiani et al , 2017Penna et al 2015;De Palézieux et al 2018;Ahmed et al 2019;Subiela et al 2019;Piacentini et al 2020;Gu et al 2021;Liu et al 2021). In recent years, GIS platforms and high-resolution DEMs have facilitated the application of geomorphometric techniques in terms of time-consumption and cost-effectiveness (Troiani et al 2014(Troiani et al , 2017.…”

Earthquake-triggered landslides and mudflows: Was this the wave that engulfed Ancient Helike?

“…During the geomorphologic analysis of the Katourlas basin, we considered the possibility of knickpoints. Lithological changes, fault tectonics and landslide damming of a river channel are commonly related to the formation of a knickpoint (Ahmed et al, 2019;Korup et al, 2010;Lague, 2014;Leopold and Wolman, 1960). At least two knickpoints are identified away from any lithological contact or faulting along the Katourlas River channel.…”

Impact of Climate Change on the Stability of the Miacher Slope, Upper Hunza, Gilgit Baltistan, Pakistan

“…The upper Hunza basin in the Karakoram Range has been reported to have higher rates of erosion [24]. The Hunza area is well-known for avalanches, debris flows, torrential slides and floods [26][27][28][29][30][31][32]. The noticeable events of calamitous occasions in locales of the Himalayan Karakorum region are the 1972 mud flow in upper Hunza, the 1974 Shishkit event BaltBar Valley mud flow with slurry avalanche, the 1977 Darkot and upper Yasin debris avalanche and the 2010 Attabad debris landslide.…”