Under to tools, add new terrain and browse through the location of the float file. Once a float is created open RAS Mapper within HEC-RAS. Unfortunately, before this can be used in HEC-RAS, this needs to be converted to a float file (flt) using any third party software.ĩ. Go back to Civil3D and export the surface as a DEM file.

HEC-RAS is a complex hydraulic design tool which is capable of conducting 1D and 2D analysis of rivers or streams.Ĩ. This process can be done separately and does not depend on the above steps. A model may contain Junctions, Lifting Station, Culverts or storage area. Aside from the hydraulic design input and quality of terrain data, The accuracy of the result will also depend on how the stream is modelled. check each cross-sections to make sure that it is still in the proper configuration.ħ. Proceed with running HEC-RAS analysis by inputting all the design parameters and assumptions. In doing this, always keep in mind that the cross-section will not reverse. > To reverse the flow, within the Geometric Data Window, go to GIS Tools and select search for. This is important to ensure that the design peak flow (discharge) will start at the Upstream and not on the Downstream. If you followed the recommendation on Step 1, you will have to reverse the direction of flow by using the tool within the HEC-RAS geometry editor. file is imported, check the stream ensuring that the direction of flow is from upstream to downstream. Within the geometry editor dialogue box, import the Geo. *Tip: having proper folder filing system is always important it is because you will be creating several file of different file types.ĥ. This should be a straight forward thing to do. if the edge (bank) of the river or stream on both side is known, trace each edge using a polyline.Ĥ. *Tip: care must be taken when creating each polylines (it would be ideal to start from left to right) although each cross-sections can be reversed within HEC-RAS.ģ. Using the Sample line command, create polylines that will represent the cross-sections along the stream alignment. I would recommend to create the alignment starting from downstream to upstream.Ģ. *Tip: Since the current version of HEC-RAS is still having some issues with regards to importing geo files from Civil3D. From Civil3D, create an alignment along the river or stream adjacent to the land or development being analyze.

Civil3D ->(Export surface to DEM) ->(Use SAGA Gis to Convert DEM to flt.

HEC-RAS ->(Import GEO file) ->(Input parameter for steady flow or unsteady flow and run analysis).

It is not intended to provide a procedure on how to conduct an analysis HEC-RAS due to the complexity of the software. This is a procedure on how to model the flood plain along rivers or streams to analyze the impact on its surrounding land or development.

Run a flt file on hec ras