Coastal Engineering Contractor Assists Flood Modeling in California and Washington

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Coastal engineer Babak Tehranirad recently joined the USGS Pacific Coastal and Marine Science Center in Santa Cruz, California, to work on the Coastal Storm Modeling System (CoSMoS). This state-of-the-art forecasting tool predicts coastal flooding and erosion under multiple storm conditions and a suite of sea-level rise scenarios.

This article is part of the December 2018-January 2019 issue of the Sound Waves newsletter.  

A man sits at a desk with 2 large computer monitors and a keyboard in front of him

Contractor Babak Tehranirad works on an operational model for forecasting flooding around San Francisco Bay. (Credit: Rex Sanders, USGS. Public domain.)

Many agencies and communities in California already use CoSMoS interactive maps for planning purposes. Babak will help the CoSMoS team expand the modeling system to cover Puget Sound in Washington State and launch an operational model for San Francisco Bay. Operational models produce routine predictions for practical use, such as weather forecasts. The San Francisco Bay model “would forecast flooding for the next 72 hours,” said Babak. The team is working with the National Oceanic and Atmospheric Administration (NOAA) to model not just offshore factors—like waves, tides, and storm surge that drive coastal flooding—but also the effects of rainfall on the rivers that flow to the bay.

Three researchers walk on a beach on a clear day with blue sky and calm seas.

Left to right: USGS scientist Josh Logan, USGS contractor Babak Tehranirad, and USGS contractor Rae Taylor-Burns (University of California-Santa Cruz graduate student) collect beach elevation data near Moss Landing, California, with precision GPS units carried in their backpacks. (Credit: Alex Snyder, USGS. Public domain.)

Because CoSMoS incorporates details of coastal terrain and the adjacent seabed, it must be tailored for each location. The modeling system is available for much of the California coast, with additional stretches continually being added. Its expansion to Puget Sound was born out of collaboration with the Environmental Protection Agency (EPA) and other partners. The CoSMoS team aims to provide flood projections along the entire Puget Sound shoreline, which hosts many communities, including Seattle and Tacoma.

“It’s a very complicated area,” said Babak, "with a tangle of inlets and islands." He will accompany the CoSMoS team to Puget Sound in February. “I’m always interested in fieldwork,” he said. “As a modeler, I want to know the environment that I’m modeling.” Meanwhile, “when I go home at night, I spend a lot of time on Google Earth” looking at the complex shoreline.

“Babak’s background in coastal-flood modeling makes him a valuable addition to our team,” said USGS research geologist Patrick Barnard, who leads the CoSMoS project.

Babak earned B.S. and M.S. degrees in Civil Engineering (Marine Structures) at the University of Tehran, Iran. For his master's thesis, he generated a numerical model to calculate how far waves would run up on the shore and how much force they would exert on coastal structures. He came to the United States to study at the University of Delaware, where he earned a Ph.D. degree in Coastal Engineering. During that time, Babak worked on several aspects of tsunami modeling, including source simulation (creating models of the events that produce tsunamis, such as earthquakes and underwater landslides), ocean-basin wave propagation (modeling how tsunami waves move through the open ocean), and inland flooding (modeling how tsunami waves change as they interact with the shore and flood over coastal areas). As part of the National Tsunami Hazard Mitigation Program for the U.S. East Coast, he participated in several tsunami inundation mapping projects, including one that assessed tsunami hazards in New York City.

After receiving his Ph.D. degree, Babak came to the San Francisco Bay area and worked for two years as a coastal engineering consultant. He was involved in several projects focused on bluff recession and wetland restoration, as well as sea-level rise vulnerability, mitigation, and adaptation. Babak was eager to get back into research, and in September of 2018, the USGS hired him as a contractor. “He has just the skill set we need,” said research oceanographer Li Erikson, modeling director for the CoSMoS team.

When he’s not working, Babak might be hiking or skiing (he has skied since he was two years old, and his college team won the speed-skiing championship in a 2005 competition among Iran’s public universities). Additionally, “I picked up being a big fan of American football since I moved to the U.S.,” said Babak, “and I'm an Eagles fan. I love playing beach volleyball, and I have a podcast, in Persian, about European soccer.”

Welcome, Babak!