How to Plan for More Extreme Climate Conditions
New report assesses adaptation strategies for transportation infrastructure
September 30, 2020: A recent SACOG report on how to assess and plan for climate risks to transportation infrastructure suggests installing drinking fountains for some transit stops and installing fiber optic cable along the US 50 to improve communications for wildfire evacuation routes.
These are just a couple of possible adaptation strategies from “Project-Level Climate Adaptation Strategies for Transportation in the SACOG Region,” which examines the risks facing individual transportation assets. That report is paired with a “Vulnerability and Criticality Assessment” report that examines climate risks at a systemic level.
Recent events, from the 2017 failure of the Oroville dam spillway to the current record-breaking wildfire season, show the potential consequences of increasingly extreme climate conditions. The spillway failure came during the wettest months on record in the 110-year history of the Feather River hydrologic record and as of September 28 in the current record-setting wildfire season, there have been 7,982 fire incidents with 3,627,010 total acres burned, including 7,630 structures damaged or destroyed and at least 26 fatalities. The first, third, fourth, fifth, and sixth-largest fires in California’s history are all currently burning or have recently been contained.
Under a changing climate, extreme weather events are projected to pose increasing risks to the transportation system. And climate hazard resiliency is an area of growing emphasis at both the state and federal levels — state agencies and the projects they fund must take climate change impacts into account.
SACOG’s report provides guidance for transportation practitioners to address climate change risk at the project level in the region and offers recommendations for advancing the resilience of the region’s transportation system. Among the high-level advice is the importance of considering timing. For example, if risk is tolerable early in an asset’s lifecycle and adaptation options are costly to implement, then it may make sense to monitor conditions and implement the action at a later point. However, agencies should be mindful of the potentially long duration of the project planning, design, and construction process and not delay addressing issues for too long.
Construction of new assets gives the opportunity to address climate risk in the design of the asset. The marginal costs of adapting a planned future asset to a climate-related risk are often relatively small compared to a baseline alternative that assumes the climate will remain the same in the future. Worth bearing in mind: investigations following the Oroville spillway failure showed that the risks were present in the project documentation but had been overlooked or ignored. The cost of repairing the damage was more than $1 billion.
At a smaller scale, the report includes case studies of representative projects from the Metropolitan Transportation Plan/Sustainable Communities Strategy to demonstrate the following principles:
•How to use FHWA’s ADAP to guide project-level climate change assessments
•How to modify project-level assessments based on assets and hazards reviewed
•How to develop and review adaptation options,
•How to compare cost-effectiveness of different adaptation options
•How to holistically review variables that affect decision-making and account for uncertainty
•How to develop a set of responses at the asset level.
In the case of extreme heat at a bus stop at Zinfandel Plaza Rancho Cordova, the report authors considered that the bus stop had a single shade canopy but no other shade options. The bus stop was in the middle of a parking lot and idling vehicles could exacerbate heat pollution there.
Potential cost-effective adaptations included:
•Install a water fountain
•Install a high-pressure water mister
•Install a cool wall shelter
•Develop a list of shade trees adapted to future climate conditions through a partnership with the Sacramento Tree Foundation
•Plant shade trees
•Install permeable/green pavement at the site (could be on the concrete pad the shelter sits on).
A bonus of planting a tree is that according to research by scholars at the University of Minnesota, having a shade tree near a bus stop can make a 10-minute wait for a bus feel like seven minutes. So stay cool out there, transportation planners!