Possibilities of Using Low Quality Digital Elevation Models of Floodplains in Hydraulic Numerical Models

Abstract

Abstract:The paper presents a method for the correction of low quality DEMs, based on aerial photographs, for use in 2D flood modeling. The proposed method was developed and tested on the example of the floodplain of the Warta River, which is the third biggest river in Poland. The correction of DEM is based on a series of a small number of measurements using GPS-RTK, which enable calculations of the global statistics like mean error (ME), root mean square error (RMSE) and standard deviation (SD). The impact of DEM accuracy was estimated by using a 2D numerical model. The calculated values of flow velocities, inundation area and volume of floodplain for each tested DEM were compared. The analyses indicate that, after the correction procedure, the predictions of corrected DEM based on poor quality data is in good quantitative and qualitative agreement with the referenced LIDAR DEM. The proposed method may be applied in the areas for which high resolution DEMs based on LIDAR data are not available.

River Bathymetry Model Based on Floodplain Topography

“…Both evaluated errors for the ALS model are >1. Note that the mean water depth in the channel at the time of acquiring ALS data was around 1 m. This suggests that the ALS model neglected almost the entire flow area of the river channel [16,20,28,42]. The RMSE and MAE values for the CRO model were 0.46 and 0.36 m, respectively.…”

“…Thalweg derived from the ALS model was shifted toward the water surface, where it fluctuated. Thus, it is evident that almost the entire flow area was neglected [16,20]. The CRO model had higher deviations relative to the BAT…”

“…The most commonly used method for creating a DEM with correct bathymetry is to merge topographic (e.g., ALS) data with another source of bathymetric data. Often used for this purpose are acoustic Doppler current profilers (ADCP), Sound Navigation and Ranging (SONAR) techniques, theodolites, and Global Positioning System (GPS) stations [3,19,20]. The main advantage of these methods is their high accuracy of the acquired data.…”

Reduction of the Warta River Flow Caused by Seepage From River Bed, During Additional Discharge From Jeziorsko Reservoir

“…Tutaj, przy wszelkich analizach istotne znaczenie ma dokładność stosowanego numerycznego modelu terenów przyległych do rzeki [Bates 2012, Yan i in. 2015, Laks i in. 2017] jak również wiarygodne rozpoznanie geotechniczne [Tschuschke 2006b;Tschuschke i in.…”

Hydraulic Conditions of Water Flow in Seminatural Fish Pass, a Case Study of the Skórka Barrage on the Głomia River

“…Such structures can vary from small hydraulic engineering objects to large facilities such as power plants, reservoirs or barrages. Hydraulic structures have a significant impact on their immediate surroundings [Laks et al 2013, Wiatkowski 2015, Laks et al 2017. They change natural habitats of living organisms, particularly those prevailing in rivers [Mazur et al 2015, Michalik et al 2015, Radecki-Pawlik 2015.…”