addressing climate change adaptation in regional transportation plans

Addressing Climate Change Adaptation in Regional Transportation PlansA Guide for California MPOs and RTPAs6.2 ADAPTATION PROJECTS ELEVATED DUETO EXTREME WEATHER EVENTSThe impetus for planning for climate adaptation can be instigated by majorextreme weather events or natural disasters that have the potential to becomemore frequent and/or more severe with climate change.For example, the Confusion Hill Bypass in Mendocino County is an example ofhow a project can be accelerated due to extreme weather events. The ConfusionHill Bridges are a pair of high bridges carrying two lanes of U.S. Highway 101over the South Fork Eel River in Mendocino County in northern California. Theold route weaved through a river canyon that was closed yearly due tolandslides. Between 1997 and 2006, landslides would become an annualoccurrence, with earth and rocks covering the road and bringing traffic andbusiness to a halt. Caltrans spent more than $33 million in the nine-year periodclearing debris and repairing the road under Confusion Hill. Because of the highcosts of maintaining the old section and potential safety issues that perpetuallyposed a risk to travelers, Caltrans and the County secured $65 million inemergency relief funding from the FHWA and constructed the Bypass,completed in 2009.Another example is the proposal by Caltrans to move three miles of Highway 1in Big Sur as far as 475 feet inland in order to protect against expected clifferosion underneath the current stretch of highway. In 2011, a landslide closedHighway 1 near Big Sur in Monterey County, a major regional and recreationroute, forcing motorists to make a long inland detour using U.S. Highway 101.The two-month closure prompted Caltrans to review this stretch of roadway toconsider the most relocation as a form of adaptation; in this case, an extreme andcostly adaptation option.These examples reflect how existing extreme weather events already posehazards to the regional transportation system. Using these examples as extremepossibilities can help provide insight into the types of impacts that climatechange may intensify.6-6 Cambridge Systematics, Inc.