2014/07/16 Council Agenda Packet

As mentioned previously, the potential impacts to transportation infrastructure from climate change include, among other things, increased flooding and deterioration of roadways. The planning horizon currently extends 20-30 years, but adaptive response to a changing climate may call for a much longer planning horizon. Other potential strategies could include the following: ■ Changes to the design assumptions of roadway and other facilities. • For example, the design of facilities such as bridges may have to be reevaluated, similar to what has been done on the three projects mentioned in Section 5, to consider the potential future impacts from increased flooding and higher water levels. ■ Changes to the siting of new facilities. ❖ For example, current planning may allow the siting of facilities and infrastructure in locations that may be vulnerable under scenarios of increased flooding or sea level rise. ■ Creating operational response plans. ❖ To create a more resilient transportation system, expanding the redundancy of systems could be considered, including an analysis of the connectivity and vulnerability of the system. ■ Incorporation of the expected increases in maintenance costs in long-range planning and capital budgets. • Inventory of critical, high -value infrastructure to evaluate the potential risks from the impacts of climate change. There is much additional research and analysis that can and should be conducted in this area to provide technical assistance and policy guidance as the region and all levels of government begin to incorporate adaptation into their planning processes. By its very nature, the topic of adapting to a changing climate is filled with uncertainties and unknowns. Since climate change has the potential to affect so many diverse sectors of the economy, the benefits of future research and analysis can be shared among them, including the transportation community. For example, the Gulf Coast Study Phase 1 suggests the following additional information will be critical in estimating the impacts of a changing climate on transportation infrastructure and services: ■ Climate Data and Projections: higher resolution of climate models for regional and subregional studies, and additional information regarding the projections of extreme weather events and storms. • Risk Analysis Tools: new tools to address the inherent uncertainties in climate projections, and to identify thresholds for adaptive response. Region -Based Analysis: demographic responses to climate change, land use interactions and economic impacts to the loss of transportation services, identifying challenges among different regions. ■ Interdisciplinary Research: collaboration between the transportation community and climate researchers. Within the central Puget Sound region, as mentioned in Section 3, the installation of land motion sensors near high -value assets such as the waterfront and port areas would provide measurement of the vertical motion of the land (i.e., uplift and subsidence) and would provide useful data in performing future risk assessments related to sea level rise and the vulnerability of these areas. A more thorough evaluation of specific facilities, population and employment centers potentially impacted by the scenarios described in Sections 3 and 4 would be required should the region choose to pursue a more robust approach to the issue of adaptation and its incorporation into long-range planning efforts. This could include a consideration of the priority of certain facilities, such as access to hospitals or schools, or in terms of the resiliency of the system. This paper is not intended to provide a comprehensive overview of this issue, nor to make recommendations for action or provide policy guidance. This paper is intended to provide an initial summary of the issue of adaptation to a changing climate and the implications to transportation infrastructure in the central Puget Sound region. While there may be significant costs involved with the incorporation of adaptation into transportation planning, as described in Section 4 there are also significant costs from the impacts of increased flood and storm events. This is an important topic and will most likely continue to be addressed at the national and state levels. As already mentioned, Ecology and the Federal Highway Administration have begun work in this area and have L-21 Appendix L: Climate Change Background