The Uncertainty of Local Flow Parameters During Inundation Flow Over Complex Topographies with Elevation Errors

Tsubaki Ryota

Kawahara Yoshihisa

Journal of Hydrology

Since the topographical data obtained from LiDAR (Light Detection and Ranging) measurements is superior in resolution and accuracy as compared to conventional geospatial data, over the last decade aerial LiDAR (Light Detection and Ranging) has been widely used for obtaining geospatial information. However, digital terrain models made from LiDAR data retain some degree of uncertainty as a result of the measurement principles and the operational limitations of LiDAR surveying. LiDAR cannot precisely measure topographical elements such as ground undulation covered by vegetation, curbstones, etc. Such instrumental and physical uncertainties may impact an estimated result in an inundation flow simulation. Meanwhile, how much and how these topographical uncertainties affect calculated results is not understood. To evaluate the effect of topographical uncertainty on the calculated inundation flow, three representative terrains were prepared that included errors in elevation. Here, the topographical uncertainty that was introduced was generated using a fractal algorithm in order to represent the spatial structure of the elevation uncertainty. Then, inundation flows over model terrains were calculated with an unstructured finite volume flow model that solved shallow water equations. The sensitivity of the elevation uncertainty on the calculated inundated propagation, especially the local flow velocity, was evaluated. The predictability of inundation flow over complex topography is discussed, as well as its relationship to topographical features.

inundation simulation

complex topography

LiDAR

shallow water flow model

LIC

water level profile

Construction. Civil engineering [ 510 ]

eng

Copyright (c) 2013 Elsevier B.V. All rights reserved.

[ISSN] 0022-1694

[DOI] 10.1016/j.jhydrol.2013.01.042

[DOI] http://doi.org/10.1016/j.jhydrol.2013.01.042