DamsLessons from the Oroville Dam incident

Published 12 April 2017

U.S. dams and levees received a grade of “D” in the American Society of Civil Engineers’ 2017 report card on national infrastructure, meaning they are in poor to fair condition and mostly below standard, with many components near the end of their service life. Experts examining the recent Oroville dam incident in California, say that the massive hole in the dam’s primary spillway and excessive erosion in the emergency spillway, along with a levee breach near Manteca, “clearly demonstrate how extreme events, land-cover and land-use changes, and the emerging climatic changes can threaten the integrity of our aging dams and levees.”

Water cascading through football-field-sized hole in the Oroville dam // Source: theconversation.com

In a letter in Science magazine, Farshid Vahedifard, a Mississippi State University (MSU) Bagley College of Engineering assistant professor of civil and environmental engineering, examines lessons gleaned from the recent Oroville dam incident in California. Vahedifard says recent incidents, including a massive hole in the dam’s primary spillway and excessive erosion in the emergency spillway, along with a levee breach near Manteca, “clearly demonstrate how extreme events, land-cover and land-use changes, and the emerging climatic changes can threaten the integrity of our aging dams and levees.”

MSU notes that Vahedifard penned the letter, along with MSU doctoral student Shahriar Shahrokhabadi and civil and environmental engineering colleagues from the University of California, Irvine, including Amir AghaKouchak, Elisa Ragno and Iman Mallakpour.

The letter in Science notes that the Oroville dam incident occurred when the wettest year on record (as of mid-rainy season) followed a record-setting five-year drought. The authors assert, “We need to reevaluate failure probability of all major dams and levees under multi-hazard scenarios. Ignoring the underlying relationships between multiple events can lead to underestimation of extreme events and their impacts.”

The nation’s dams and levees received a grade of “D” in the American Society of Civil Engineers’ 2017 report card on national infrastructure, meaning they are in poor to fair condition and mostly below standard, with many components near the end of their service life.

Vahedifard studies how a variety of hazardous conditions, including droughts, heavy rainfall, high temperatures, high levels of air moisture and other natural conditions may affect critical infrastructure, including levees and dams. However, his research interests also include how urban development and other anthropogenic activities may intensify the impact of natural hazards on various infrastructure and increase the likelihood of damage during climatic events.

“These are very important issues that need to be studied closely so that we can begin to close the gap in our understanding in terms of uncertainty in climatic extremes under a changing climate and their impacts on the resilience of infrastructure. We should incorporate research findings into engineering practice for evaluating existing infrastructure, as well as planning and designing future infrastructure,” Vahedifard said.

MSU says that Vahedifard, principal investigator of a $212,000 National Science Foundation grant, is leading a three-year collaborative and interdisciplinary research project to quantitatively assess the performance of critical geotechnical infrastructure, including natural and engineered earth structures like levees, to climatic extremes and natural hazards under current and changing climatic conditions. The outcome is expected to increase understanding about the resilience and reliability of infrastructure under current climate trends.

— Read more in Farshid Vahedifard, “Lessons from the Oroville Dam,” Science 356, no. 6330 (17 March 2017) (doi: 10.1126/science.aan0171)