چکیده:
A significant deficiency of most computer models used for stream floodplain analysis is that the locations of structures impacted by floodwaters, such as bridges, roads, and buildings, cannot be effectively compared to the floodplain location. This research presents a straightforward approach for processing output of the HEC-RAS hydraulic model, to enable two- and three dimensional floodplain mapping and analysis in the ArcView. The methodology is applied to a reach of Polasjan River Basin, located in Iran central plateau. A digital terrain model is synthesized from HEC-RAS cross-sectional coordinate data and a digital elevation model of the study area. The resulting surface model provides a good representation of the general landscape and contains additional detail within the stream channel. The results of the research indicate that GIS is an effective tool for floodplain mapping and analysis.
خلاصه ماشینی:
Floodplain mapping using HEC-RAS and GIS in semi-arid regions of Iran Abstract A significant deficiency of most computer models used for stream floodplain analysis is that the locations of structures impacted by floodwaters, such as bridges, roads, and buildings, cannot be effectively compared to the floodplain location.
This research presents a straightforward approach for processing output of the HEC-RAS hydraulic model, to enable two- and three dimensional floodplain mapping and analysis in the ArcView.
The approach establishes a connection between the HEC-RAS hydraulic model and ArcView GIS, allowing for improved visualization and analysis of floodplain data.
The main research objective is develop a procedure to take computed water surface profiles generated from the HEC-RAS hydraulic model and draws a map of the resulting floodplain in ArcView GIS.
In the HEC-RAS coordinate system, the coordinate of any given point is based on its river station along a one-dimensional stream centerline, location along the cross-section line, and elevation.
In order to map the hydraulic modeling output in GIS, the differences between the HEC-RAS and ArcView coordinate systems must be resolved.
The approach is based on assigning map coordinates to stream cross-sections and computed water surface profile data stored in HEC-RAS model coordinates.
Because the approach presented herein assumes that input terrain model is not the source of the cross-section descriptions, the GIS data export option in HEC-RAS is not employed.
HEC-RAS represents stream floodplains as a computed water surface elevation at each cross-section.
The procedure consists of several steps: data import from HEC- RAS, stream centerline representation, cross- section georeferencing, terrain modeling, and floodplain mapping.