Geometric data consist of establishing the connectivity of the river system (River System Schematic), entering cross-section data, defining all the necessary junction information, adding hydraulic structure data (bridges, culverts, dams, levees, weirs, etc…), pump stations, storage areas, and two-dimensional flow areas. The geometric data is entered by selecting Geometric Data from the Edit menu on the HEC-RAS main window. Once this option is selected, the Geometric Data window will appear as shown in Figure 5-1. The drawing area will be blank on your screen, until you have either drawn in your own river system schematic or imported data from a GIS.

IMPORTANT NOTE: The current version of HEC-RAS has the ability to lay out the geometry of a model (i.e. stream centerline, cross sections, storage areas, 2D flow areas, and hydraulic structures) in either the Geometric Data editor or HEC-RAS Mapper. HEC is moving towards having a completely geospatial layout system for developing the geometry using HEC-RAS Mapper. The tools in the Geometric data editor are the original tools for developing a geometric model. All of the new tools for geospatially laying out the model geometry are in HEC-RAS Mapper. If you want to use HEC-RAS Mapper to layout the geometric data model, please read the HEC-RAS Mapper User's manual. Once you have a model laid out within HEC-RAS Mapper, you can extract terrain data for cross sections, storage areas, 2D flow areas, and hydraulic structures. However, to complete the parameterization of the model (i,e, cross section coefficients, structure modeling approaches and coefficients, etc…) you must come back into the Geometric data editor to complete all the required Geometric data for the model.
This chapter describes how to enter and edit all of the necessary geometric data for a river system using the Geometric Data editor.

The following topics will be discussed in this section:

  • Developing the River System Schematic
  • Cross Section Data
  • Stream Junctions
  • Bridges and Culverts
  • Multiple Bridge and/or Culvert Openings
  • Inline Structures (Weirs and Gated Spillways)
  • Lateral Structures (Weirs, Gates, Culverts, and Rating Curves)
  • Storage Areas
  • Two-Dimensional Flow Areas
  • Storage Area/2D Flow Area Hydraulic Connections
  • Pump Stations
  • Cross Section Interpolation
  • River Ice
  • Viewing and Editing Data Through Tables
  • Importing Geometric Data
  • Geometric Data Tools
  • Georeferencing an HEC-RAS Model
  • Attaching and Viewing Pictures
  • Saving the Geometric Data