Sustainable Resilience Program
The Arizona Department of Transportation (ADOT) manages 30,000 maintenance lane miles, 4,750 bridges, and one international border, all spread over 114,000 square miles. The agency and its assets need to function from sea level to 6,000 feet and withstand temperatures from below 0°F to over 120°F. ADOT’s mission to provide a safe, efficient, cost effective transportation system can be compromised from the effects of heat extremes, dust storms, wildfires, flooding, landslides, rockfall incidents, and slope failures. In order to cope with the ever-growing cost of these threats, ADOT set out to develop a resilience program that could incorporate existing planning, design, construction, operations, and maintenance criteria; identify a strategic and systematic framework, take advantage of available technologies, tools, and partnerships; build upon their 2014 Preliminary Study of Climate Adaptation for the Statewide Transportation System in Arizona and the 2015 Extreme Weather Vulnerability Assessment Final Report; and contribute to the national conversation surrounding these topics. Since ADOT has had a long history considering the balance between predictable asset deterioration curves and the unknown, erratic, and abrupt incidents of flood, overtopping, system hotspots, hydraulic-related failure, and extreme weather impacts, these topics were identified to make up the core of the resilience program. Moreover, the program represents the partnerships undertaken to further evidence-based decision making, the opportunities from next generation ground based LiDAR (Light Detection and Ranging) and drone-based photogrammetry services, and data collection platforms that can advance magnitude of peak flow engineering efforts.
Transportation infrastructure is a complex system of assets required to deliver a myriad of services and functions. As fiscal constraint for the development and rehabilitation of such structures continues to be cost prohibitive, new and novel approaches to life cycle costing and long term planning become paramount. In addition, the management of these infrastructure systems has now evolved from a decentralized, project based focus to one that now encompasses enterprise wide Agency undertakings – extreme weather and future climate impacts is one such endeavor. Three areas of vexing concern for state DOTs and the main catalyst for developing an ADOT Resilience Program involve how to:
- Centralize to one operating area the unknown, erratic, and abrupt incidents of stormwater and its contributors of flooding (overflow of water that submerges land), overtopping (rise over or above the top), system hotspots (roadway flood prone history), hydraulic-related failures (structure failure mechanisms)
- Introduce extreme weather adaptation to agency and engineering design processes and establish transportation asset sensitivity to extreme weather
- Handle scientifically-informed climate data downscaling as it relates to transportation systems
At the national level, enhanced flood event decision making is the current focus of NCHRP 20-59 (53) synthesis and was initiated to identify “existing tools, methods, data and models” that could contribute to a scalable flood event planning framework. The localized effects of overtopping and known system hotspots have the largest impact on maintenance budgets. Hydraulic-related failure and the subsequent difficulty in modeling groundwater flows, roughness coefficient, channel energy, and critical shear stress is the focus of NCHRP report 761. The ADOT resilience program links risk, science, technology, and engineering to advance probabilistic methodology.