Climatologists predict El Niño may bring torrential rainfall to Arizona in 2016. If they’re right, many civil engineers in the state will be better prepared having completed a training course for a new hydraulic modeling program at the University of Arizona.

Nearly 50 engineers, hydrologists and others working in flood control attended two-day training workshops on the UA campus Jan. 11 and 12, 2016, and previously in July 2015 to get hands-on practice using HEC-RAS 5.0, the forthcoming upgrade of the Army Corps of Engineers’ flow-simulation software. The workshops were free for state and local government employees.

Arizona presents special flood-control challenges, said Jennifer Duan, associate professor in the Department of Civil Engineering and Engineering Mechanics, who led the workshops. The state’s combination of dry, poorly absorbent desert soil and few culverts or canals to divert surface water flows can lead to rapid flooding, especially in urban areas like Tucson.

“Most Arizonans reside in alluvial fans, expanses of land formed by river sediment, with no defined open channels, she said. “When flooding occurs, the water can flow everywhere.”

In 1997 and 1998, during the last major El Niño event -- a periodic warming of Pacific Ocean waters that affects weather patterns worldwide -- Arizona received record-breaking snow and rainfall causing widespread structural damage and road closures in Tucson, Phoenix and Flagstaff.

Engineers use hydraulic modeling to predict how water and sediment travel through rivers and streams and determine which areas are most likely to get inundated during storms. Until 10 years ago, these programs were one-dimensional, limiting users’ ability to accurately map water flows, especially in shallow water.

The Army Corps of Engineers’ forthcoming Hydrologic Engineering Center River Analysis System, or HEC-RAS 5.0, is its first two-dimensional version of the software. Duan and her UA students have been beta-testing the program, which should become available in the next few months.

Duan, a leading expert in flow simulation, has developed another 2-D hydraulic modeling software, CHRE2D, or Computational Hydraulics and River Engineering 2-D, and has worked with Tech Launch Arizona, the UA office that commercializes inventions stemming from University research, to make it commercially available.

“Everyone who works in floodplain mapping is going to have to learn to use this new software,” said Ann Moynihan, civil engineering manager for the Pima County Regional Flood Control District and member of the UA civil engineering and engineering mechanics department’s Alumni Industry Council.

“Dr. Duan’s rapid response to this training need and the workshops’ success suggest the department could offer more such courses for professional engineers in Arizona,” she said.

City of Tucson hydraulic engineer Loren Makus attended the January workshop to help him evaluate proposed projects’ compliance with drainage regulations.

“I get a lot of data from engineers and hydrologists using HEC-RAS for designing residential and commercial projects,” he said. “I took this course to make sure I understand the methods developers use in coming up with their numbers -- and to determine just how good those numbers are.”

The department of civil engineering and engineering mechanics sponsored the UA workshops. For more information on hydraulic modeling training opportunities at the UA, contact Jennifer Duan.