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

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 OPEN ACCESSWater 2014, 6 272 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.

Accuracy of DSM By Using Unmanned Aerial Vehicles on the Downstream of Welang Riverbank, District of Pasuruan, Jawa Timur

“…To model a river flood, topography data with sufficiently high resolution are necessary to represent the geometric features of the river channels and floodplains [1], [2]. However, most areas vulnerable to floods are relatively flat.…”

Synergistic Approach of Remote Sensing and GIS Techniques for Flash-Flood Monitoring and Damage Assessment in Thessaly Plain Area, Greece

“…Qian et al [57] also used LiDAR-derived DEM for the extraction of uncultivable trails, ditches, and cultivated field parcels within flood plains in order to evaluate flood risk. Furthermore, Vesakoski et al [58] investigated the effect of various sources of digital terrain models (DTM) on the delineation of topographic depressions and their hydrological impacts.…”

Combining SAR and Optical Earth Observation with Hydraulic Simulation for Flood Mapping and Impact Assessment

“…Especially, in a flat plain area, the precision of flood assessment directly depends on the analysis of the DEM [13,45]. A high-resolution DEM is crucial to extract the details of the topography, acquire the water surface elevations, and simulate flood inundation and depth [13,46,47].…”