Landslide hazard zonation, mapping and investigation of triggering factors in Phewa lake watershed, Nepal

Abstract

The landslide triggering factors were investigated followed by the thematic maps and landslide distribution map prepared and classified using the GPS and GIS Softwares like CartaLinx, ArcView and ERDAS IMAGINE in Sarangkot and Kaskikot Village Development Committees, Kaski district. In analytical hierarchy process, the factors for zonation were compared by Couple Comparison Method and their weights were determined using Arithmetic Mean Method and earned weight values of each factor. The landslide hazard zonation model was employed to prepare landslide hazard zonation map of the study area, and then classified into five relative hazard classes using the equal interval classification method. Finally, the landslide hazard zonation map was crossed with the landslide distribution map and the model applicability was confirmed by determining the per hazard class percent of area covered by the landslide. In the land hazard zonation map, 0.44% of the study area was in very low hazard, 2.11% in low hazard, 54.92% in moderate hazard, 21.34% in high hazard and 21.19% in very high hazard area. The major portion of the study area was on the moderate zone whereas the least portion was on the very low hazard zone. In the study area, most of the high and very high hazard class areas were found occupying the areas closer to the linear triggering factors like presence of linement and fault, presence of motorable road and presence of rivers and streams. The landslide density of the study area was found to be 0.44 per km2 indicating the higher hazard susceptibility of the area.DOI: http://dx.doi.org/10.3126/banko.v22i2.9198Banko Janakari: A Journal of Forestry Information for NepalVol. 22, No. 2, 2012 November Page: 43-52 Uploaded date: 12/1/2013

Quantifying the Spatiotemporal Pattern of Urban Expansion and Hazard and Risk Area Identification in the Kaski District of Nepal

“…Thulibesi phant in Armala, where 117 sinkhole spots were observed, is exposed to severe sinkhole hazards [55]. Sarangakot and Kaskikot within the Phewa watershed [56] and the Rupakot area of the Rupa watershed [57] are prone to landslide hazards. The Phewa Lake catchment area in Pokhara witnessed a shallow seated landslide due to extreme rainfall in 2007 [51].…”

“…A detailed geographical study of Pokhara, Kaski was carried out by Gurung in 1965 [66]. Yet, there are few studies have assessed the hazard risk scenario [54][55][56][57][58] and urbanization trends [67,68] of Pokhara City and the Seti watershed [8]. However, long-term time-series studies of urbanization and the hazard risk of the entire Kaski District is lacking.…”

Landslide Hazard Mapping in Panchase Mountain of Central Nepal

“…With 556 landslides, the landslide density in the Panchase area was found to be 1.99 per km 2 . In research conducted at a location nearby this experimental site, landslide densities of 0.44 per km 2 (Basnet et al, 2006) and 0.571 per km 2 (Bhatt et al, 2013) were found in Phewa and Rupa watersheds, respectively. Phewa watershed is a part of the present study area.…”

“…In the case of land use, we can observe a higher amount of landslide area in forests and cultivated lands which are 0.762 km 2 and 0.358 km 2 respectively which together accounted for 75% of the total landslide area. A study in Phewa watershed had also found higher landslides among forests (Basnet et al, 2006) whereas cultivation lands had higher landslides in a study at Mugu District (Budha et al, 2016). Bhatt et al (2013) also found higher landslides in cultivated lands than in forests.…”

“…The landslide densities had increased by four folds since 2006 when the first research was carried out in Phewa watershed. Only 16 landslides recorded by Basnet et al (2006), in Sarangkot and Kaskikot which are now ward number 18 and 24 of Pokhara respectively, had now increased to 30. The landslide susceptibility mapping done in 2016 used 80 landslides (Pradhan and Kim, 2016) which had increased to 260 during the time of this research.…”