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Comparing the accuracy of several field methods for measuring gully erosion

Castillo, Carlos and Pérez, Rafael and James, Michael and Quinton, John and Taguas, Encarnación V. and Gómez, José A. (2012) Comparing the accuracy of several field methods for measuring gully erosion. Soil Science Society of America Journal, 76. pp. 1319-1332. ISSN 0361-5995

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Abstract

Most fi eld erosion studies in agricultural areas provide little information on the probable errors involved. Here, for the fi rst time, we compare the accuracy, time and cost of conventional and new methodologies for gully surveying, and provide a model to estimate the effort required to achieve a specifi ed accuracy. Using a terrestrial LiDAR survey of a 7.1-m-long gully reach as a benchmark data set, the accuracies of different measurement methods (a new 3D photo-reconstruction technique, total station, laser profi lemeter, and pole) are assessed for estimating gully erosion at a reach scale. Based on further fi eld measurements performed over nine gullies (>100 m long), a simulation approach is derived to model the expected volume errors when 2D methods are used at the gully scale. All gullies considered were located near Cordoba, Spain. At the reach scale, the fi eld measurements using 3D photo-reconstruction and total station techniques produced cross-sectional area error values smaller than 4%, with other 2D methods exceeding 10%. For volume estimation, photo-reconstruction proved similar to LiDAR data, but 2D methods generated large negative volume error (EV) values (<–13% for laser profi lemeter and pole). We show that the proposed error expressions derived from the model are in line with the reach-scale fi eld results. A measurement distance factor (MDF) is defi ned that represents the ratio between cross-section distance and the gully length, and thus refl ects relative survey effort. We calculate the required MDF for specifi ed values of EV, illustrating how MDF decreases with increasing gully length and sinuosity.

Item Type: Article
Journal or Publication Title: Soil Science Society of America Journal
Uncontrolled Keywords: Soil erosion ; SfM-MVS
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 53798
Deposited By: ep_importer_pure
Deposited On: 01 May 2012 11:41
Refereed?: Yes
Published?: Published
Last Modified: 17 Aug 2012 10:51
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/53798

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