scholarly journals Understanding erosion rates in the Himalayan orogen: A case study from the Arun Valley

2015 ◽  
Vol 120 (10) ◽  
pp. 2080-2102 ◽  
Author(s):  
Stephanie M. Olen ◽  
Bodo Bookhagen ◽  
Bernd Hoffmann ◽  
Dirk Sachse ◽  
D. P. Adhikari ◽  
...  
Keyword(s):  
Himalayan Orogen ◽  
Erosion Rates

scholarly journals MATLAB Virtual Toolbox for Retrospective Rockfall Source Detection and Volume Estimation Using 3D Point Clouds: A Case Study of a Subalpine Molasse Cliff

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 75
Author(s):  
Dario Carrea ◽  
Antonio Abellan ◽  
Marc-Henri Derron ◽  
Neal Gauvin ◽  
Michel Jaboyedoff
Keyword(s):  
Point Cloud ◽  
Natural Hazard ◽  
Point Clouds ◽  
Volume Estimation ◽  
Natural Phenomena ◽  
Frequency Distributions ◽  
Erosion Rates ◽  
3D Point Clouds

The use of 3D point clouds to improve the understanding of natural phenomena is currently applied in natural hazard investigations, including the quantification of rockfall activity. However, 3D point cloud treatment is typically accomplished using nondedicated (and not optimal) software. To fill this gap, we present an open-source, specific rockfall package in an object-oriented toolbox developed in the MATLAB® environment. The proposed package offers a complete and semiautomatic 3D solution that spans from extraction to identification and volume estimations of rockfall sources using state-of-the-art methods and newly implemented algorithms. To illustrate the capabilities of this package, we acquired a series of high-quality point clouds in a pilot study area referred to as the La Cornalle cliff (West Switzerland), obtained robust volume estimations at different volumetric scales, and derived rockfall magnitude–frequency distributions, which assisted in the assessment of rockfall activity and long-term erosion rates. An outcome of the case study shows the influence of the volume computation on the magnitude–frequency distribution and ensuing erosion process interpretation.

Effects of simulated water level management on shore erosion rates. Case study: Baskatong Reservoir, Québec, Canada

2001 ◽  
Vol 28 (3) ◽  
pp. 482-495 ◽  
Author(s):  
Diane Saint-Laurent ◽  
Bachir N Touileb ◽  
Jean-Phillippe Saucet ◽  
André Whalen ◽  
Benoit Gagnon ◽  
...  
Keyword(s):  
Bank Erosion ◽  
Water Levels ◽  
Reservoir Water ◽  
Field Surveys ◽  
Erosion Rates ◽  
Sandy Material ◽  
Water Level Management ◽  
Wave Erosion ◽  
Main Factor

This study was carried out as part of a feasibility study on the construction of a hydroelectric generating station at Mercier dam at the outlet of the Baskatong reservoir in Québec. The study dealt mainly with a comparison of the current and future bank erosion rates of the reservoir. Given the year of impounding of the Baskatong reservoir, i.e., 1927, it was possible to track bank erosion rates using field surveys and photogrammetric and numerical analyses. It was noted that in certain areas, such as Du Diable Bay and Windigo Bay, the Baskatong reservoir banks were substantially affected by erosion. Estimates indicate that the banks have receded by about 10 to 15 m over a 20-year period. The banks most affected by erosion are those containing sandy material of fluvioglacial or glaciolacustrine origin with bluffs greater than 2 m in height and characterized by the longest fetches. In one section of Windigo Bay, banks had receded by about 30 m in 20 years. Wave action is the main factor responsible for bank erosion, especially in areas highly exposed to long fetches. In fact, there is a correlation between bank erosion rates, fetch distribution, and the erosive energy of waves. It has been noted that receding banks with the highest erosion rates are linked to the greatest wave erosion energy. Based on the values obtained using simulated reservoir water levels, while taking into account the future construction of a new generating station, bank erosion rates appear to be comparable to those measured under actual conditions, though erosion rates could increase by about 28–30% in the areas most affected by erosion at the present time.Key words: bank erosion, waves and fetch, erosion rates estimated, Baskatong Reservoir, Québec, Canada.

scholarly journals Channel Planform Dynamics along Distributary Channels: Case Study of the River Nun a Major Distributary of the River Niger

2019 ◽  
pp. 1-11
Author(s):  
Tombra S. Akana ◽  
O. C. Adeigbe
Keyword(s):  
Gis And Remote Sensing ◽  
Migration Rates ◽  
Erosion Rates ◽  
Sensing Applications ◽  
Accretion Rates ◽  
Remote Sensing Applications ◽  
The Right ◽  
River Niger ◽  
Channel Planform

Channel planform dynamics were analyzed for the River Nun; a major distributary of the River Niger from 1985 to 2015 using GIS and Remote sensing applications. Satellite imagery of the area from 1985, 1995, 2005, and 2015 were analyzed by means of GIS and used to determine the planform characteristics and changes in width, sinuosity, and shoreline migration rates. The channel planform dynamics were determined by comparing sequential changes in the position of the shorelines in these years. Sinuosity adjustments during the study were small and range between 1.74–1.76. The initial sinuosity (1.74 in 1985) increased to 1.75 in 1995 and then increased to 1.76 in 2015. Channel expansion is observed to be the dominant planform process, owing to periodic floods within the study area. The river’s channel width barely expanded from 1985 to 1995 (by 0.1 %). However, there is a constant increase in expansion within the study years that by 2005-2015 expansion had increased to 9%. The bank erosion was prevalent. Mean erosion rates ranged from 0.7 m/year in 20 years (1985-2005) to 2m/year in 30 years (1985-2015). In the 1st 10 years (1985-1995) less than 0.1 m of deposition was observed. The mean erosion rates ranged from 1.3 to 1.6 m/year on the left side and 2.8 to 3.8 m/year on the right side of the channel. Mean accretion rates of 1.2 m/year on the left side and 1.8 m/year on the right side were observed. The channel is observed to move generally towards the east (right).

Assessment of gully erosion rates through interviews and measurements: a case study from northern Ethiopia

2006 ◽  
Vol 31 (2) ◽  
pp. 167-185 ◽  
Author(s):  
Jan Nyssen ◽  
Jean Poesen ◽  
Maude Veyret-Picot ◽  
Jan Moeyersons ◽  
Mitiku Haile ◽  
...  
Keyword(s):  
Gully Erosion ◽  
Northern Ethiopia ◽  
Erosion Rates
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