This project was initiated following a recent increase in significant weather-related events that impacted California’s transportation system over the past few years. California legislation requires consideration of climate change for all state investments.
In 2015, heavy rains washed out a bridge on Interstate 10, impacting travel and goods movement on this critical roadway. In June 2017, a major landslide deposited tons of rock along Highway 1. And last December, dry weather conditions contributed to wildfires in both Northern and Southern California, which had a significant impact on travelers.
Near Santa Barbara, the loss of protective landcover due to wildfires resulted in a major mudslide during heavy rains that closed Highway 101 for weeks. In the last year alone, Caltrans incurred over $1.2 billion dollars in highway damage. The state also has over 840 miles of coastline that raise concerns about long-term coastal flooding and the impacts of climate change.
“This report provides Caltrans with its first inventory of assets that require additional consideration due to climate change,” Flood said. “It covers a broad set of stressors so that Caltrans can focus its efforts on maintaining the resiliency of the highway system to ensure it can withstand changing conditions, additional forces and long-term water levels as a part of new infrastructure design.”
While climate change studies typically focus on the impact of rising sea levels, this study also paid close attention to other factors, such as storm surge, precipitation change, temperature change, wildfires and coastal erosion/cliff retreat.
“Temperature change, for example, is important to consider when designing roadway pavement, to ensure that it remains viable for longer periods,” Flood said. “Precipitation change can impact how bridges and culverts are designed, and the potential for increased damage caused by flooding can be important to asset management considerations. Precipitation is also an important consideration in landslide risk.”