About the Software

The CD-ROM in the back of this book contains an academic version of HEC-Pack. HEC-Pack includes HEC-RAS, HEC-HMS, and HEC-GeoRAS from the U.S. Army Corps of Engineers Hydrologic Engineering Center (HEC) and Graphical HEC-1 from Haestad Methods. The following provides a brief summary of the individual software packages. For detailed information on the software and how to apply it to solve floodplain modeling problems, see the help systems included on the CD-ROM.

HEC-RAS

Lay out your river networks graphically.
Calculate water surface profiles based on steady and unsteady, gradually varied flow for channel networks, dendritic systems, or a single river reach.
Predict energy losses based on Manning's friction coefficients, and expansion and contraction losses.
Evaluate floodway encroachments for floodplain management and insurance studies.
Determine changes in water surface profile due to levees, bridges, and culverts.
Handle rapidly varied flow conditions automatically, such as hydraulic jumps and bridge contractions.
Modify a range of cross sections using the channel improvement options (and obtain the cut and fill volumes).
Include in-line weirs and gated spillways in the river system.
Compute bridge scour based on the routines outlined in HEC-18 (Hydraulic Engineering Circular 18, from the Federal Highway Administration).
Follow the methods for low-flow computations laid out by the Federal Highway Administration using the WSPRO bridge routines.
Analyze culverts under supercritical and mixed flow regimes, and adverse slopes.
View the results three-dimensionally with X-Y-Z perspective plots.
Conduct stable channel design, levee breach and dam break analysis, ice jam analysis, and other specialized modeling tasks.

HEC-HMS

Schematically build your hydrologic network, including such elements as sub-basins and routing reaches.
Model hypothetical storm events based on frequency.
Consider historical storm events through cell-based precipitation data.
Import precipitation data from other sources.
Specify gages and a method of weighting the gages, including user-defined and inverse distance-squared weighting.
Compute sub-basin runoff in either a lumped or linearly distributed fashion.
Determine losses based on several methods, including Green and Ampt, SCS Curve Number, gridded SCS Curve Number, and the Initial/Constant method.
Transform precipitation to runoff through either unit hydrograph methods (Clark, Snyder, or SCS) or Kinematic Wave methods.
Route hydrographs using Kinematic Wave, Modified Puls, Muskingum, or Muskingum-Cunge.
Divert flow, either "losing" the diverted hydrograph or adding it back in further downstream.

Graphical HEC-1

Build your hydrologic network graphically, by dragging and dropping elements (such as sub-basins, routing reaches, reservoirs, etc.) into your schematic.
Use gauged rainfall data, standard design rainfall distributions, or synthetic rainfall patterns.
Enter rainfall distributions, basin areas, infiltration losses, and routing methods.
Convert rainfall to direct runoff using any combination of five different loss methods, including SCS Curve Number, HEC Exponential, Initial and Uniform, Green and Ampt, and Holtan.
Generate runoff hydrographs using SCS, Clark, Snyder, or a user-defined unit hydrograph method.
Divert and route hydrographs through natural and man-made reaches and reservoirs.
View hydrographs at any point in the network, in tabular form or graphically.
Work with hydrographs on-screen, print them out, or export them to other software programs (spreadsheets, word processors, etc.) via the Windows Clipboard.

HEC-GeoRAS

Use GIS to create HEC-RAS import files including river, reach, and station identifiers; cross-sectional cut lines; downstream reach lengths for the left and right overbanks and main channel; and cross-sectional roughness coefficients.
Automate the creation of additional geometric data from your GIS including information for defining levee alignments, ineffective flow areas, and storage areas.
Export water surface profile and velocity data from HEC-RAS to your GIS in order to perform additional spatial analyses and mappings.