Nationwide Digital Terrain Models for Topographic Depression Modelling in Detection of Flood Detention Areas

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openAccess

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Journal Title

Journal ISSN

Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2014

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Mcode

Degree programme

Language

en

Pages

271-300

Series

WATER, Volume 6, issue 2

Abstract

Topographic depressions have an important role in hydrological processes as they affect the water balance and runoff response of a watershed. Nevertheless, research has focused in detail neither on the effects of acquisition and processing methods nor on the effects of resolution of nationwide grid digital terrain models (DTMs) on topographic depressions or the hydrological impacts of depressions. Here, we quantify the variation of hydrological depression variables between DTMs with different acquisition methods, processing methods and grid sizes based on nationwide 25 m × 25 m and 10 m × 10 m DTMs and 2 m × 2 m ALS-DTM in Finland. The variables considered are the mean depth of the depression, the number of its pixels, and its area and volume. Shallow and single-pixel depressions and the effect of mean filtering on ALS-DTM were also studied. Quantitative methods and error models were employed. In our study, the depression variables were dependent on the scale, area and acquisition method. When the depths of depression pixels were compared with the most accurate DTM, the maximum errors were found to create the largest differences between DTMs and hence dominated the amount and statistical distribution of the depth error. On the whole, the ability of a DTM to accurately represent depressions varied uniquely according to each depression, although DTMs also displayed certain typical characteristics. Thus, a DTM’s higher resolution is no guarantee of a more accurate representation of topographic depressions, even though acquisition and processing methods have an important bearing on the accuracy.

Description

VK: T20508

Keywords

ALS, DTM, nationwide DEM, grid size, topographic depression, flood detention

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Citation

Vesakoski , J-M , Alho , P , Hyyppä , J , Holopainen , M , Flener , C & Hyyppä , H 2014 , ' Nationwide Digital Terrain Models for Topographic Depression Modelling in Detection of Flood Detention Areas ' , WATER , vol. 6 , no. 2 , pp. 271-300 . https://doi.org/10.3390/w6020271