ISPRS-Archives The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ISPRS-Archives Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci. 2194-9034 Copernicus Publications Göttingen, Germany 10.5194/isprs-archives-XLII-4-W18-1065-2019 LIDAR AND PHOTOGRAMMETRY APPROACHES FOR MONITORING LAND SURFACE MORPHOLOGY IN EPHEMERAL GULLY SYSTEM Xu X. 1 Tang Q. https://orcid.org/0000-0002-0886-6699 1 Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, PR China 19 10 2019 XLII-4/W18 1065 1069 Copyright: © 2019 X. Xu 2019 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://isprs-archives.copernicus.org/articles/XLII-4-W18/1065/2019/isprs-archives-XLII-4-W18-1065-2019.html The full text article is available as a PDF file from https://isprs-archives.copernicus.org/articles/XLII-4-W18/1065/2019/isprs-archives-XLII-4-W18-1065-2019.pdf

LIDAR and photogrammetry techniques were used to quantify the land surface morphology dynamics of ephemeral gully system based on the field investigation. LIDAR monitoring results showed that ephemeral gully occurred in the same location on the slope surface after every rainy season in the ephemeral gully system, then lateral topsoil was tilled and brought into the ephemeral gully channel, inducing 2 cm decrease around channel before rainy season of next year, which make it a cycle of erosion-tillage-erosion. During this process, imbricated landform was formed in ephemeral gully system. The photogrammetry monitoring results showed that most drop-sills distances in ephemeral gully channel were in 10 to 25 cm, while slope gradients were among 15° to 40°. The drop-sills distance and slope gradient showed negative exponent relationship. The results of this study showed that LIDAR technology can quickly acquire the topographic characteristics of the whole ephemeral gully system, while photogrammetry method could quickly acquire detailed morphology in ephemeral gully channel.