The basic computational procedure is based on the solution of the one-dimensional energy equation. The steady flow component is capable of modeling subcritical, supercritical, and mixed flow regimes water surface profiles. The system can handle a full network of channels, a dendritic system, or a single river reach. This component of the modeling system is intended for calculating water surface profiles for steady gradually varied flow. User-Defined Rules for Controlling Gate Operations.Transport and fate of a limited set of constituents.The latest version HEC-RAS includes the following new features: Tabulation and Graphical Displays of Input and Output Data.The interface provides for the following functions: The main focus in the design of the interface was to make it easy to use the software, while still maintaining a high level of efficiency for the user. The user interacts with HEC-RAS through a graphical user interface (GUI). X-Y-Z (pseudo 3-D) graphics of the river system.Tributary/diversion flow network capabilities, allowing for fully looped river system analysis in which reaches can be subdivided and combined.Inline weirs and gated spillways analysis, including both radial and sluice type gates and Ogee, broad and sharp crested weirs.Geometric model schematic can be placed over background maps and incorporate clickable scanned images of structures.User Defined Rules for Controlling Gate Operations.Water Quality Capabilities (Temperature Modeling).Sediment Impact Analysis Methods (SIAM).Sediment Transport/Movable Bed Modeling.Lateral flow, split flow, overbank dendritic networks.FEMA Floodplain and floodway encroachment modeling.Bridge design editor and graphical cross section editor.Bridge scour computations following FHWA Publication HEC-18.Multiple bridge and culvert openings of different types and sizes at a roadway crossing.Bridge and culvert analysis and design, including FHWA culvert routines for elliptical, arch, and semi-circular culverts.Mixed flow regime analysis, allowing analysis of both subcritical and supercritical flow regimes in a single computer run.

Hec ras 2d manual