Research for detecting structural deterioration on sea dikes using low altitude aerial photography image analysis taken by UAV

Ooishi, Tetsu; Shiratani, Eisaku; Kiri, Hirohide; Takahashi, Junji; Mizukami, Koji; Muraki, Hirokazu

doi:10.2208/kaigan.71.i_1717

Cited by 4 publications

(1 citation statement)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Examples of aerial photogrammetry using UAVs are increasing because the economic efficiency and mobility of UAVs are excellent in small-range surveys. The accuracy of aerial photogrammetry using our UAV is approximately 25-40 mm when the height of the UAV is less than 50 m (Oishi, 2015).…”

Section: Aerial Photogrammetry Using Uavsmentioning

confidence: 99%

Sediment dynamics of mountain streams as a function of variation in sediment deposition

Nakanishi

Okajima

Baba

et al. 2018

Journal of Nepal Geological Society

View full text Add to dashboard Cite

In Japan, the management of sediment in dam reservoirs has become challenging owing to heavy rain. Unexpected increase of sediment volume in dam reservoirs can increase flood risk owing to a rise in the level of the riverbed. It is therefore necessary to conduct sediment management to clarify the area of sediment production to control the amount of sediment transported and the timing of its movement. Sediment discharge from tributaries is often calculated based on catchment area and the deposited sediment volume already present in the dam reservoir. However, our preliminary surveys have implied that it is also necessary to consider regional geology in the evaluation of sediment transport. Moreover, variations in sediment deposition should be evaluated for each site where the geology changes. In this study, we observe in detail changes in the riverbed in two tributaries with different regional geologies. Changes in the shape of the riverbed were analyzed from unmanned aerial vehicle observation data, following which the effects of erosion and sedimentation on the riverbed were quantitatively evaluated. Finally, sediment discharge was calculated by a one-dimensional numerical model of sediment transport. These results indicate that the tributary that is mostly composed of mudstone produced considerably more sediment than the tributary composed mainly of sandstone. This suggests that an understanding of regional geology is necessary in the evaluation of sediment dynamics and should be considered in addition to the catchment area.

show abstract

Section: Aerial Photogrammetry Using Uavsmentioning

confidence: 99%