Hydrological processes modeling using GIS ARCGIS and module HEC-RAS

Aim of this research is to determine the area of land flooding according to a reasonably chosen hydrological model for a complex section of the Dniester River at the place of transition from the foothill to the plain with complex meandering and significant shifts of the river. Methods. The method of investigation of flooded areas as a result of water rise to a certain level has been processed. It includes: survey of the area with UAVs; the implementation of geodetic and hydrological activities in the field of research; creation of DEM based on survey results and analysis of its accuracy; hydrological modeling using the HEC-RAS software package; and determination of flood areas. In order to obtain the digital elevation model, which is the basis for hydrological modeling, a Trimble UX5 UAV with a Sony NEX-5R camera was used. To accurately determine DEM coordinates, a standard error for horizontal coordinates of 6 cm was established; elevation coordinates depending on the basis of images and the underlying surface equals 0,21m. The DEM was created using the specialized software Pix4D. GPS data was given as input to the hydrological modeling. Results. The DEM was created according to the results obtained from the UAV to the average quadratic error of 0.2 m. The technique of hydrological modeling implemented on the part of the Dniester River with a complex configuration of the channel was processed. Areas have been designated including the area of flooding at different water levels of. Scientific novelty is the development of a methodology for determining flooded areas based on the hydrological modeling using the HEC-RAS module for the Dniester River section, which is characterized by significant erosion of coastal soils, complicated meandering and transition from foothill to plain topography. Such conditions require precise determination of modeling parameters. In order to obtain input data for flood modeling, the UAV survey was carried out with a preliminary justification of the accuracy characteristics. The practical significance. Hydrological modeling is performed in order to predict the consequences of material losses due to flood events occurring in the Pre-Carpathian region. The timely receipt of information about these processes; and the monitoring of hydrological posts on the water level, which fills the beds and floodplains, allow through appropriate administrative structures to notify the population and take measures to reduce the losses resulting from these devastating phenomena. The proposed study is aimed at obtaining information on flood areas due to different levels of water uplift in the Dniester River.