Model Library

Hydrologic Engineering Center’s River Analysis System (HEC-RAS)

Model name: Hydrologic Engineering Center’s River Analysis System (HEC-RAS)

Developed by: U.S. Army Corps of Engineers (Last update: 2024)

Model type: 1D/2D, process-based, hydraulic, hydrodynamic and water quality, waterbody model

Computational requirements: 64-bit Windows, Linux, 64-bit Tiles Server

Software requirements: GIS (optional): HEC-Geo RAS

Link to download model

Capabilities and Limitations:

Capabilities

  • HEC-RAS is a highly precise model for predicting water levels and flood-affected areas during extreme hydrological events, even with limited input data (Zainal and Abu Talib, 2024);
  • HEC-RAS is widely regarded as one of the best software tools for flood inundation mapping (Namara et al., 2022);
  • One of the most popular hydrodynamic models (Kumar et al., 2017;
  • HEC-RAS 5.0.1 and later versions enable independent 2D modeling, including comprehensive flood analysis and mapping within the RAS Mapper tool (Pathan & Agnihotri, 2020);
  • The model can simulate flooding events and generate water surface profiles along the modeled stream (Namara et al., 2022).

Limitations

  • HEC-RAS cannot model supercritical flow, for which both discharge and water level are controlled by the upstream boundary (Armas Andrei et al, 2017);
  • Model code is not publicly available;
  • HEC does not provide support to non-USACE users (USACE, n.d.).
  • HEC-RAS 2D lacks infiltration loss and spatially distributed rainfall (Garcia et al., 2020);
  • Currently, the types of hydraulic structure that could be modeled within HEC-RAS 2D are few and do not have the same computational detail of the 1D version of the model (Garcia et al., 2020);
  • The model assumes channel slope is equal to zero (Toombes and Chanson, 2011);
  • HEC-RAS model has not been generally adopted as a water quality model (Zainal and Abu Talib, 2024).
  • HEC-RAS does not offer considerations to wind speed, wave radiation, infiltration and eddy viscosity (Shrestha et al., 2020)

Model Inputs and Outputs:

Inputs

Aerial map, DEM, Channel cross-section data, Land use, Hydraulic structures, Sediment, Water quality, Streamflow data, Water surface elevation, Discharge

Outputs

HEC-RAS model can simulate discharge, flood animations, flood inundation map, water surface elevation, cross-section and profiles, and transport and diffusion process of water quality indicators such as total nitrogen, ammonia nitrogen, nitrous nitrogen, orthophosphate, algae, ammonia nitrogen, and chemical oxygen demand.

Examples:

References

Kim, J., Jonoski, A., Solomatine, D. P., & Goethals, P. L. M. (2023). Water quality modelling for nitrate nitrogen control using HEC-RAS: Case study of Nakdong River in South Korea. Water, 15, 247. https://doi.org/10.3390/w15020247


Tamiru, H., & Dinka, M. O. (2021). Application of ANN and HEC-RAS model for flood inundation mapping in lower Baro Akobo River Basin, Ethiopia. Journal of Hydrology: Regional Studies, 36, 100855. https://doi.org/10.1016/j.ejrh.2021.100855

Objectives

The objective of this study is to suggest guidelines for designing strategies to control NO3-N in Nakdong River using a process-based model developed with HEC-RAS.

The main objective of this study is to integrate the ANN flood prediction technique with HEC-RAS model to generate flood hazard areas by developing flood inundation depths.