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Transportation, Climate Change & Extreme Weather Vulnerability Assessment Webinar Series

Session 1 Q&A: "Getting Started: Determining Assets to Study and Using Climate Information"

May 16, 2013 Question and Answer Session Summary

Question: Please explain subsidence as an issue in vulnerability assessments.

Response (Rob): Some parts of the East and West Coasts don't have much subsidence. Some areas of Alaska and the Gulf Coast, however, do have subsidence issues. Subsidence is a factor that goes along with future rise in sea level. If land is subsiding, that can magnify the effect of storm surges or sea level rise. Conversely, uplift can moderate the effect of sea level rise.

Question: I noticed on one of the Gulf Coast 2 maps that "critical pipelines" were mapped. Could you talk about assessing the criticality of pipelines?

Response (Mike): For the criticality of pipelines, we had to rely on engineering judgment. The system was developed based on the volume of pipeline facilities, what was in them, and whether they made connection to power plants in the region. That was the basic framework of how pipelines were assessed for the region.

Question: Will any of these studies (i.e. the New Jersey Transportation Planning Authority or Gulf Coast Study) actually result in actual transportation improvement, for example more elevated highways or higher seawalls?

Response (Becky): The pilot studies are too recent to have resulted in actual transportation improvements, and they were primarily for planning. The Washington State Department of Transportation (WSDOT) did generate a map of vulnerable facilities that they have incorporated into their State NEPA guidance. As a result, if WSDOT is planning work on a project at a facility identified as vulnerable, they will need to look at climate change adaptation considerations as part of the project development process. There are not many examples such as this though, as it is all happening at the planning level.

Response (Joel):Transportation infrastructure is being adjusted. In the Gulf they've rebuilt higher after Katrina. People are looking at improved defenses post-Sandy and people are looking at making infrastructure more robust. Climate change is being taken more seriously. These studies help contribute to the knowledge base to inform these types of decisions.

Question: Did any of the studies integrate the results into decisionmaking?

Response (Becky): WSDOT did and the Metropolitan Transportation Commission (MTC) is using their results further. The third webinar in this series will discuss incorporating results into planning. These pilot studies were completed two years ago and the results are going into the planning process, but the process is long, so they may not have been incorporated yet.

Response (Rob): We are talking about six or seven different studies, but other areas are considering vulnerability beyond the ones we are talking about today.

Question: When determining scope, is project-level better than corridor study?

Response (Becky): That depends on what you are looking for, particularly whether you are interested in a specific project or a broader look at vulnerability.

Response (Joel: )When we were looking at the New Jersey Transportation Planning Authority (NJTPA), we didn't just look at individual projects. You can downscale to the project level but it's more reliable at a broader, regional scale. You can still use that information to look at effects across a corridor or region.

Response (Mike:) One of the keys is to think about the risks that are associated with each of the levels and then figure out the cost increment at the project level to obtain a higher level of risk avoidance. It's a similar process, but it could be applied at either the project/corridor or system level.

Question: What are your thoughts on migration of barrier islands with changes in sea level?

Response (Rob): One would expect sea level rise to make barrier islands move and change more quickly than they otherwise would. These are questions that depend on how fast things change.

Question: What are the prospects for greater precision and accuracy in the models? Are the ranges of outputs likely to be narrowed over time?

Response (Joel): These models have been around since the 1960s. The models have gotten better over time as our knowledge and technology have improved. The resolution has improved, for example. At some point in the future even global models will be down to 60 miles across. They are doing a better job of simulating climates now than ever. They are on average, better at simulating climates. One problem, however, is whether we are getting more agreement. Even as the models have gotten better, there are still variations of findings and wide ranges of projections. Unless there is a scientific breakthrough it is unlikely we will see a narrowing of those projections. We have to live with uncertainty for the time being, but we do have model information to use to understand the range of outcomes. If you need to make adaptation decisions you have to work with what we have.

Question:What effects does harbor dredging have in reducing storm surge impacts?

Response (Mike): In terms of whether flood depth was used to assess damage to transportation infrastructure, we are at the phase where the whole Gulf Coast Project is coming together. We are taking downscaled climate data and methodologies to break it down to the engineering level and conduct benefit/cost assessments to see how you would walk through one of these at the project level. One of these studies will be completed by end of this year with a publication in 2014. That's the end phase of the Gulf Coast 2 Project.

Response (Becky): Boston Harbor Association did a recent study that may have looked at dredging. A new pilot is being conducted by the Massachusetts Department of Transportation (MassDOT) that is looking at impacts on the Central Artery and potential solutions, so they may look at dredging.

Response (Rob): We do know that with coastal modeling there is a factor called depth-limited waves. If depths increase, say due to dredging, that can lead to higher wave heights. If you look at a particular dredging situation there are many local factors that come into play to determine how dredging would affect storms.

Question: Do you have knowledge of transportation projects where climate change adaptation has influenced the selection of alternatives for a given project, based on the vulnerability of the area? What about modeling/projections and its uses in the project development process and the NEPA process?

Response (Joel): The New Jersey study calculated inland flood depth as well. We used storm surge to look at the level of flood depth in coastal areas. The U.S. Army Corps of Engineers (USACE) also has policy out on sea level rise for its civil works projects

Response (Mike): Caltrans has strong guidance on sea level rise that it needs to be incorporated into the development process. North Carolina did some work on climate change for a coastal bridge and Maryland has started to assess sea level rise and its implication on bridges to barrier islands. There is NEPA guidance out that addresses long-term climate change in terms of long-range transportation planning and how that fits into documenting the potential environmental impacts, particularly in coastal areas.

Response (Becky): In Washington State, many projects have looked at potential climate change impacts. Several states do look at potential vulnerabilities and the impacts of climate change.

Question: Is the next Intergovernmental Panel on Climate Change (IPCC) assessment expected to provide new or better information for modeling and climate predictions?

Response (Joel): The information will be new and the models do get better as I mentioned, in terms of resolution, physics, and observations. As an aside, these are the same classes of models as those used for weather forecasting. The British forecasted Sandy's turn into New Jersey from the Atlantic a week in advance. That wouldn't have happened ten years ago. Models now are doing a better job at simulating weather and climate. Just the same, there is the same level of disagreement, but they represent better science that the older set of models. The IPCC is issuing its fifth assessment on the science of climate change this fall.

Question: Does the FHWA have formal guidance for incorporation of sea level rise into project design?

Response (Becky): We do not have formal guidance. We agree that you probably should consider SLR if you have that information.

Response (Rob): We allow places to do things with federal funds. There was a joint memo between Federal Lands, the Office of Infrastructure, and the Office of Environment & Planning that explained that funds can be used to address climate assessments, but there is not specific guidance on incorporating sea level rise into project development at this point.

Question: Do you know of a transportation project that has published an Environmental Impact Statement (EIS) that addressed climate change in the impact analysis?

Response (Becky): You can look at recent EIS's from Washington State and California that included sea level rise analysis and climate change impacts. New York State's EIS's do as well. They all look at greenhouse gas analysis. These EIS's sometimes look at climate change impacts, for example the Columbia River Crossing and State Route 522 projects in Washington State. The Government Accountability Office (GAO) put out a study recently on how federal agencies are addressing climate change impacts, including FHWA, Washington State, and Louisiana.

Question:Is the HEC25b effort going to provide guidance for sea level rise modeling?

Response (Rob): There is currently guidance for designing transportation facilities in the coastal environment called HEC25 and we currently have an effort to put together information on how to do modeling on storm surges and sea level rise. That's an ongoing research project.

Response (Joel): The National Resource Council (NRC) put out a report for the West Coast states and they recommended 0.5 -1.5 meters. The Gulf Coast Study used up to 2 meters. It depends on how risk adverse you are. I suggest using multiple scenarios. You want to at least test how your responses hold up under a wide range of scenarios. That's critical for this type of analysis. Test for a reasonable range of potential changes.

Updated: 03/27/2014
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