Original paper
Analysis of geomorphic changes and quantification of sediment budgets of a small Arctic valley with the application of repeat TLS surveys
Kociuba, Waldemar
Zeitschrift für Geomorphologie, Supplementary Issues Volume 61 Supplementary Issue 2 (2017), p. 105 - 120
published: Nov 1, 2017
DOI: 10.1127/zfg_suppl/2017/0330
ArtNo. ESP023106102006, Price: 29.00 €
Abstract
The article reports the application of high-resolution repeat Terrestrial Laser Scanning (TLS) surveys in the assessment of erosion and deposition volumes in the valley of the Tyvjobekken Creek (NW part of the Wedel-Jarlsberg Land, Spitsbergen, and Svalbard). High resolution (> 300 points m– 2) data was obtained across the estuarial part of the valley with an area of 92,631 m 2 during the culmination of melt- water seasons 2010 and 2013. The field works involved the application of a Leica Scan Station C10, and Real Time Kinematic Global Positioning System (GPS RTK). A complex survey was carried out from 5 (2010) and 24 (2013) interrelated measurement sites. Three square-shaped test areas (of 10,000 m2 each) located in the central and lower parts of the valley were designated for the evaluation of medium-scale morphological transformations. 3D scanning at each of the sites permitted obtaining a point cloud of ~5 million points (M pt.). The resulting clouds of data of 25.5 and 155.5 M pt (respectively) were used for the development of digital elevation models (DEMs) of the river valley with a length of more than 0.6 km and width of up to 0.2 km for both of the field campaigns (in 2013 1.2 km and 0.45 km, respectively). TLS-based difference digital elevation models (DoD) were compared. High definition TLS surveys showed great registration accuracy 0.009 m during field campaign 2010 and better than 0.02 m in 2013. Changes in morphology were identified throughout a 3-year period. 55% of the study area was eroded (51,339 m2), particularly in the lower parts of the valley floor (gorge section), south slope, and alluvial fan. This resulted in the removal of 6,691 m3 of sediment volume. Deposition concerned 45% of the study area – 5,207 m3 of sediment volume respectively. The subtraction of consecutive DEMs of the test areas revealed downstream spatial and volumetric differentiation: from deposition predominance in the central part of the gorge (65%, 6,475 m2, 128.6 m3), through erosion predominance in the mouth part of the gorge (60%, 6,021 m2, 196.6 m3), to the dominance of erosion in the central part of the alluvial fan (98%, 9,534 m2, 601.2 m3).
Keywords
morphological sediment budgeting • small arctic valley • geomorphic changes • repeat tls surveys • dem of difference (dod)