What the HEC?
Past, Present, and Future
2024 marked the 60th anniversary of the founding of the U.S. Army Corps of Engineers Hydrologic Engineering Center. One year later, we celebrated the 30th anniversary of HEC-RAS software, with Version 1.1 released in 1995.
Watch our free Australian Water School webinar covering a nostalgic look into the past, some demonstrations of current capabilities, and a look at the road ahead.
Download a pdf version of the webinar slides below:
Webinar Resources
Following are links to some of the historical manuals, papers, and other resources referenced during the webinar:
The HEC team in 1967:
The HEC team in 2024:
Related Webinars
Tune into our free physical modelling webinar for a guided tour of the Mississippi River Basin Model, a predecessor to the code in HEC-2!
Tune into our free rip rap sizing webinar for a historical review of the physical models and equations that form the background for today’s code:
HEC VS. HEC
H&H trivia question: Does the “H” in HEC stand for hydrologic or hydraulic?
H&H trivia answer: Well, the answer depends whether you’re dealing with the U.S. Army Corps of Engineers or the U.S. Department of Transportation Federal Highway Administration. In relation to the Corps of Engineers’ Hydrologic Engineering Center, the “H” stands for Hydrologic, but to the Department of Transportation that publishes Hydraulic Engineering Circulars, it stands for Hydraulic. If you want to avoid confusing them, just remember that the FHA publications always use two digits and avoid dashes (HEC 05 is FHWA whereas HEC-5 is USACE).
For reference, here’s a list of the HEC programs and publications of which I’m aware. If I’ve missed some, please let me know.
Legacy U.S. Army Corps of Engineers Hydrologic Engineering Center Software along with the current software packages that followed from the original FORTRAN code:
- HEC-1 Flood Hydrograph Package => HEC-HMS
- HEC-2 Water Surface Profiles Program => HEC-RAS
- HEC-3 Reservoir Analysis for Conservation => ?
- HEC-4 Stochastic Streamflow Generation Program => ?
- HEC-5 Simulation of Flood Control and Conservation Systems => HEC-ResSIM
- HEC-6 Scour and Deposition in Rivers and Reservoirs => HEC-RAS
Current software supported by the Hydrologic Engineering Center:
- CWMS Corps Water Management System
- HEC-DSS Data Storage System
- HEC-DSSVue Data Storage System Viewer
- HEC-EFM Ecosystem Functions Model
- HEC-EFM Plotter Ecosystem Functions Model Plotter
- HEC-FDA Flood Damage Reduction Analysis
- HEC-FIA Flood Impact Analysis
- HEC-GeoDozer Terrain data editor for HEC-GeoHMS
- HEC-GeoEFM ArcGIS extension for Ecosystem Functions Model
- HEC-GeoHMS ArcGIS extension for HEC-HMS
- HEC-GeoRAS ArcGIS extension for HEC-GeoRAS (no longer supported)
- HEC-GridUtil HEC-DSS gridded data set utilities
- HEC-HMS Hydrologic Modeling System
- HEC-LifeSim Life loss and economic damage simulation system
- HEC-RAS River Analysis System
- HEC-ResPRM Prescriptive Reservoir Model
- HEC-ResSim Reservoir System Simulation
- HEC-RPT Regime Prescription Tool
- HEC-RTS Real Time Simulation
- HEC-SSP Statistical Software Package (Originated with FREQFLOW, includes former HEC-FFA flood frequency analysis and Bulletin 17B & 17C, formally called HEC-WRC Water Resources Council)
- HEC-WAT Watershed Analysis Tool, including FRA Flood Risk Analysis
- Water Quality Modules built into HEC-RAS, HEC-ResSIM, and HEC-HMS
Federal Highway Administration Hydraulic Engineering Circulars:
- HEC 01 Selected Bibliography of Hydraulic and Hydrologic Subjects (Archived)
- HEC 05 Hydraulic Charts for the Selection of Highway Culverts (Archived)
- HEC 09 Debris Control Structures Evaluation and Countermeasures (October 2005)
- HEC 10 Capacity Charts for the Hydraulic Design of Highway Culverts (Archived)
- HEC 11 Design of Riprap Revetment (Archived)
- HEC 12 Drainage of Highway Pavements (Archived)
- HEC 13 Hydraulic Design of Improved Inlets for Culverts (Archived)
- HEC 14 Hydraulic Design of Energy Dissipators for Culverts and Channels (July 2006)
- HEC 15 Design of Roadside Channels with Flexible Linings (September 2005)
- HEC 16 Addendum to 1975 Highways in the River Environment (Archived)
- HEC 17 Highways in the River Environment – Floodplains, Extreme Events, Risk, and Resilience (June 2016)
- HEC 18 Evaluating Scour at Bridges (April 2012)
- HEC 19 Hydrology (Archived)
- HEC 20 Stream Stability at Highway Structures (April 2012)
- HEC 21 Design of Bridge Deck Drainage (May 1993)
- HEC 22 Urban Drainage Design Manual (September 2009)
- HEC 23 Bridge Scour and Stream Instability Countermeasures (Vol. 1, September 2009)
- HEC 23 Bridge Scour and Stream Instability Countermeasures (Vol. 2, September 2009)
- HEC 24 Highway Stormwater Pump Station Design (February 2001)
- HEC 25 Highways in the Coastal Environment (October 2014)
- HEC 26 Culvert Design for Aquatic Organism Passage (October 2010)
Another area of overlap between USACE and FHWA (not to be confused with FHA, the Federal Housing Administration) is that the Federal Highway Administration publishes the Hydraulic Design Series documents, one of which (HDS 5) serves as the basis for inlet-control culvert computations in HEC-RAS. Here are the HDS publication of which I’m aware:
- HDS 2 – Highway Hydrology (October 2002)
- HDS 3 – Design Charts for Open Channel Flow (August 1961)
- HDS 4 – Introduction to Highway Hydraulics (June 2008)
- HDS 5 – Hydraulic Design of Highway Culverts (April 2012)
- HDS 6 – River Engineering for Highway Encroachments (December 2001)
- HDS 7 – Hydraulic Design Safe Bridges (April 2012)
Have a look inside HDS 5 in our Hydraulic Structures Webinar:
If anyone happens to know what became of the FHWA documents HEC 02 through 04 and HEC 06 through 08 along with HDS 1, please let me know so I can complete my list! I’m also curious what current USACE programs HEC-3 and HEC-4 morphed into if anyone has further information to offer around that.
Finally, for the real retro fans, here is a list of FORTRAN programs that the Corps of Engineers was using in 1973, most of which ended up incorporated into one or more of the subsequent HEC programs (from Bugliarello and Gunther, Computer Systems and Water Resources, 1974):
HEC Chronology 1964 – 2014 from a photo I took of a wall poster in the HEC offices. [Note: if anyone has the original pdf or a better quality version of this, please let me know so I can replace these images]
- For nostalgia’s sake, here is a screen shot from HEC-RAS Version 1.0 from Chris Maeder’s “Road to HEC-RAS” article:
- HEC history from the Corps of Engineers website
- Did you know that your iPhone stores $6 million worth of memory in 1990’s prices? From punch cards and reel-to-reel tapes to today’s code, watch our recent webinar for a retro journey into the past!
More HEC Trivia
HEC trivia question: Is “HEC” pronounced as one syllable or three? Tune into the webinar to find out!
And just for fun, here is a bit of the background around HEC and the Corps of Engineers as addressed in the online polls during our recent HEC-HMS webinar:
The HEC offices are located on the second floor of a shop in Davis, California. Pop quiz Question #1:
Are the HEC offices located above:
a) Cookie Shop
b) Shavery
c) Kava bar
d) Wine bar
Other nearby choices include a smoke shop, sushi shop, Bizarro World, Ho Ho Market, and lots of pizza and coffee but the answer is all of the above. Here is a map for the key:
Pop Quiz Question #2:
Which is oldest?
a) Australia
b) United States
c) Corps of Engineers
Answer:
c) The “Corps” of Engineers comprised a chief engineer and two assistants who were appointed by George Washington when the Continental Congress organised an army on 16 June 1775, with the first task being the construction of the Bunker Hill fortifications. More from Wikipedia: U.S. Army Corps of Engineers
Pop Quiz Question #3:
What are these kayakers doing?
a) looking for the remains of Greased Lightning
b) bathymetric surveying
c) publicity stunt questioning the definition of “navigable waterways”
Read more about the controversial expedition here.
HEC Training
Visit the Australian Water School’s on-demand training page for HEC-RAS course offerings – sign up any time and complete at your convenience!
Be sure to use coupon code hydroschool-10 for a 10% discount on registration fees.
The Australian Water School also offers HEC-HMS, HEC-LifeSim, and other HEC training courses, Visit the on-demand training page to learn more, and be sure to use coupon code hydroschool-10 for a 10% discount on registration fees!
Please let us know if you are aware of any other resources we should highlight here!