HR: 0800h
AN: H41G-0847    [Abstracts]
TI: Monitoring Of Soil Erosion Using Digital Camera Under Simulated Rainfall
AU: * Moritani, S
EM: hatshige01@alrc.tottori-u.ac.jp
AF: Arid Land Research Center, Tottori University, 1390 Hamasaka, Tottori, Tottori, 680-0001, Japan
AU: Yamamoto, T
EM: yamamoto@alrc.tottori-u.ac.jp
AF: Arid Land Research Center, Tottori University, 1390 Hamasaka, Tottori, Tottori, 680-0001, Japan
AU: Henintsoa, A
EM: kojaina2002@yahoo.com
AF: Arid Land Research Center, Tottori University, 1390 Hamasaka, Tottori, Tottori, 680-0001, Japan
AU: Muraki, H
EM: muraki@ajiko.co.jp
AF: Asia Air Survey co., Ltd, 1-2-2 Manpukuji, Asao-ku, Kawasaki-shi, Kanagawa, Kanagawa, 215-0004, Japan
AB: The photogrammetry is often used to measure the amount of erosion from Digital Elevation Model (DEM). A set of DEM data for different periods is particularly important for soil erosion measurement. It helps in evaluating surface roughness changes. The photogrammetry application to soil erosion has been studied for the purpose of river channel shifting, landslide movement and gully erosion. However, there is a lack of information in monitoring small scale of soil erosion like sheet erosion, which is a slight change in soil surface compared to gully. Due to the limitation in the accuracy of photogrammetry, the objective of this study was to assess the precision of photogrammetry. A new system equipped with an automated photogrammetry was developed in our laboratory. The system consists of two digital cameras, a rain simulator with a twelve meters high tower, and a set computer image analysis program of three-dimensional algorithm. The precision was first assessed by comparing the measured data against photogrammetry under no rainfall condition. The assessment was based on the statistical parameters, the absolute error (AE) and relative error (RE), which are 0.0946 kg/m2 and 8.59%, respectively. In the second step, the precision was assessed for under simulated rainfall on soil surface packed to two different dry bulk densities. At 1.20 g/cm3 density, the AE and RE were 6.62 kg/m2 and 1490%, respectively and corresponding values at 1.30 g/cm3 density were 0.675 kg/m2 and 86.0%, respectively. The soil saturated with water and whose bulk density was 1.38 g/cm3, was subjected to rainfall of intensities of 40, 80, 120 mm/h continuously for 1 hour. They had AE (RE) of 0.0313 (36.1%), 0.0183 (26.4%), 0.0268 kg/m2 (29.8%), respectively, at each intensity. It was concluded that is possible to measure soil sheet erosion of small scale with high precision and under the rainfall.
DE: 1815 Erosion
DE: 1824 Geomorphology: general (1625)
DE: 5415 Erosion and weathering
DE: 6017 Erosion and weathering
SC: Hydrology [H]
MN: 2007 Fall Meeting