HEC-RAS Guides and Tutorials Current: Guides PDF Download PDF Download page Guides. Current page Include child pages All pages Guides Guides are intended to be short overviews of how to do something. Downloading Terrain Data GDAL Projection File Warning Skip SRS Translation For Terrain Imports Export Channel Data for Terrain Re-projecting Model Geometry Creating a Terrain Dataset to Model a Flume Experiment Modeling Steep Reaches Aligning Cell Faces in Channels with Refinement Regions Creating an Combined 1D/2D Model — This document describes the general steps required to create a river hydraulics model comprised of 1D River Reaches combined with a 2D Flow Area in HEC-RAS. Modeling Weirs in 2D Areas — This document summarizes options for modeling weirs for 2D models in HEC-RAS and provides guidance on when to use each option. Terms of Use Any use or reproduction of this material must be attributed to the US Army Corps of Engineers Hydrologic Engineering Center. ×