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9 Chapter 3 â Findings and Applications This chapter details the outcomes of the literature review, surveys and interviews, gap analysis, and guidebook development. Current State of the Practice Review The research team reviewed a broad range of materials during Phase I. Topics included in the literature review included: ï· Transportation system climate vulnerabilities and assessment methodologies ï· Capital investment frameworks ï· Operations and emergency management frameworks ï· Hazard mitigation frameworks ï· Climate resilience/adaptation approaches for transportation assets and systems ï· The state of the practice for DOTs using CBA in their decision-making processes ï· Economic guidance regarding discounting future climate impacts The team consulted materials such as academic literature, industry research, and transportation-related publications (e.g. Federal Highway Administration [FHWA], American Association of State Highway and Transportation Officials [AASHTO], and NCHRP). Tools, methods, data, and existing frameworks were a central focus of this work. Using the literature review as a basis, the research team developed an online survey that was distributed to DOTs via the Transportation Research Boardâs Committee Communication Coordinators. The results of the surveys, which are included in Technical Memorandum No. 1 attached as Appendix A of this report, indicated that expecting or experiencing adverse weather events resulting in damage may be a key driver in resilience investment decisions. However, over 90 percent of respondents had not performed economic analyses at the program level to consider investment in extreme weather and climate change. While several respondents do perform CBAs for projects considering climate resilience, many others cited limitations in existing tools, guidance, and funding (Figure 2). These efforts also enabled the research team to gain an understanding of the needs of DOTs and other infrastructure owners. The research revealed barriers and opportunities to integrate CBA into climate adaptation decision making for transportation assets and systems. Gap Analysis As a follow-up to the surveys, the research team conducted in-depth telephone interviews with several DOTs that indicated availability for follow-up interviews. The interview findings further supported the literature review findings that extreme weather impacts or, more generally, resilience, may be a factor in ClimateÂ RiskÂ Identification VulnerabilityÂ AssessmentÂ &Â Prioritization CBAÂ ofÂ AdaptationsÂ &Â Alternatives AdaptationÂ Selection Implementation Figure 2. The transportation sector has begun performing vulnerability assessments, but does not usually have a formal CBA framework to distinguish between adaptations addressing identified vulnerabilities. CBA is a key link between climate vulnerability assessments and adaptation implementation.
10 selecting projects; however, formal CBAs are rarely conducted. The results of the interviews are included in Technical Memorandum No. 2, which is attached as Appendix B to this report. Despite the factors mitigating against CBA use, DOTs indicated that they require analytical tools that will allow them to balance investments across a wide range of needs and time scales while addressing increasing risks posed by climate change and extreme weather. Ideally, such tools: ï· Make use of available data ï· Fit into existing processes ï· Complement existing methods ï· Yield cost-benefit ratios (CBR) calculated using net present value (NPV) to inform objective decision making ï· Are simple enough for immediate use, yet sophisticated enough to evolve and improve with use All methods and tools that DOTs use must be tailored to the context and decision support needs of the DOT. Tools also must be scalable so that they can apply equally to a small project and a full program and results can be compared. The results of the literature review and the interviews were analyzed to identify practitioner needs that are not sufficiently addressed at the time the data was collected: ï· Simple but effective tools targeted to infrastructure must lower the perceived barrier of complex data entry needed to perform climate resilience CBAs. ï· Inputs, data availability, and tool format need to be familiar to practitioners so that they will feel comfortable completing a CBA. ï· Outputs from CBAs that improve communication about the value of potential projects. Some CBA outputs that might be of use to practitioners include CBR, NPV, return on investment (ROI), and (modified) internal rate of return ((M)IRR). ï· The goal of a CBA is to assess costs, benefits, and trade-offs, and often to compare these across various design options, perhaps in combination with operations strategies. Costs and benefits should be discounted such that results are easily comparable across design options, alternatives, and projects. ï· CBA tools should be applicable to multiple hazards in order to quantify risks across hazards and changing climate conditions. ï· CBA tools should consider social and environmental factors to allow users to consider the full costs and benefits of a design or project. ï· Projects and plans can take place across a variety of scales ranging from a single site or transportation corridor to an entire region, state, or multi-state (cross-border collaboration) area. CBA methods need to be scalable to these levels. Table 1 summarizes how existing frameworks meet CBA needs.
11 Table 1. Summary of four existing frameworks' abilities to meet CBA needs Needs Currently Satisfied Can Be Satisfied With Minor Modification Will Require New Approaches Capital Investment Framework Data Readily Available to Transportation Practitioners X Support for Multi-Asset and Operations Analysis X Consideration of Hazards X Consideration of Non-Stationarity (Changing Climate) X Consideration of Other Resilience and Sustainability Factors X Relevance for Design-Level Alternatives Comparison X Relevance for Communication to Funding Entities and Public X Scalability from Project- to Planning-Level Analyses X Geographic Scalability X Operations, Emergency Response, and Recovery Planning Frameworks Data Readily Available to Transportation Practitioners X Support for Multi-Asset and Operations Analysis X Consideration of Hazards X Consideration of Non-Stationarity (Changing Climate) X Consideration of Other Resilience and Sustainability Factors X Relevance for Design-Level Alternatives Comparison N/A N/A N/A Relevance for Communication to Funding Entities and Public X Scalability from Project- to Planning-Level Analyses X Geographic Scalability X Hazard Mitigation Framework Data Readily Available to Transportation Practitioners X Support for Multi-Asset and Operations Analysis X Consideration of Hazards X Consideration of Non-Stationarity (Changing Climate) X Consideration of Other Resilience and Sustainability Factors X Relevance for Design-Level Alternatives Comparison X Relevance for Communication to Funding Entities and Public X Scalability from Project- to Planning-Level Analyses X Geographic Scalability X Climate Resilience Framework Data Readily Available to Transportation Practitioners X Support for Multi-Asset and Operations Analysis X Consideration of Hazards X Consideration of Non-Stationarity (Changing Climate) X
12 Needs Currently Satisfied Can Be Satisfied With Minor Modification Will Require New Approaches Consideration of Other Resilience and Sustainability Factors X Relevance for Design-Level Alternatives Comparison X Relevance for Communication to Funding Entities and Public X Scalability from Project- to Planning-Level Analyses X Geographic Scalability X Framework Development How Earlier Tasks Inform Framework Development DOTs have a number of adaptation-related tools already. For example, the FHWA Vulnerability Assessment Scoring Tool (VAST) helps DOTs think through vulnerability assessment for climate change and adaptation, but not at a cost-benefit level. Some adaptation pilots are attempting cost-benefit analysis, usually on relatively small scales such as a sample project or area. Lifecycle cost assessment resources are targeted to individual assets and systemic assessment of assets, but do not include environmental changes or vulnerabilities, or the assetsâ vulnerability to climate change or extreme weather. NCHRP Project 20- 59(50) may come the closest in utility; that projectâs application, Costing Asset Protection: An All- Hazards Guide for Transportation Agencies (CAPTA) (http://www.trb.org/NCHRP/Blurbs/176162.aspx), looks at cost asset protection guidance, though it does not specifically look at climate change impacts. The initial interviews conducted by the team during Task 2 stressed the utility and more customary usage of detailed information in the design stage. When rebuilding and answering the question of whether âbettermentsâ are justified rather than replacing in-kind, DOTs perform a cost-benefit analysis of the construction costs. However, when it comes to CBA for incorporating âbettermentsâ to address the impacts of climate change or extreme weather events specifically, many DOTs were not sure what their future analysis considerations, methodologies, or needs would be and some felt it would be âprematureâ to guess what they might be. On the other hand, some national and large-scale regional analyses from the private sector, as in Zillowâs analysis of flooding impacts for the residential sector, have been performed, using a business-as-usual (most conservative) assumption. This seems reasonable as the U.S. continues on its existing course of moderate investment in renewables while continuing a fossil-fuel dominated system (it would take departing from the latter to alter course). In most states, any consideration of climate change and extreme weather events in project decision making, or resilience or flood mitigation, is currently done on a case-by-case basis with more of a qualitative analysis than a quantitative analysis. Several states have ventured further, though, in part due to FHWAâs Climate Resilience Pilot studies. While DOTs stressed that CBA is not typically used currently, they said CBA would be useful in design and planning. There was particular emphasis on the planning level, given the importance of that stage for programming and understanding long-term demands on and direction for the agency (Figure 3), including
13 the financial burden, long-term public sector costs, and system functioning costs that temperature extremes, worsening storms, rising sea levels, and more frequent and higher nuisance flooding will impose. Some practitioners thought the benefits of CBA could be greater on capital projects, but the inputs and costs are also much greater at that level of application. If they did use CBA, DOTs variously answered that they would be most likely to use CBA in a research project (such as infrastructure impacts, future costs, and the CBA of alternate pathways versus business-as-usual) or a large project, such as a bridge or tunnel decision. In the climate change or extreme weather arena, DOTs could also use CBA for a betterment decision on an FHWA Emergency Relief project. DOTs see the need and utility for broader scale analysis in advance, so that the agency is prepared if and when disasters occur and reconstruction needs to take place quickly.
14 Figure 3. Incorporating climate adaptation and CBA into the transportation planning process could help understand future needs and determine long-term strategies for transportation agencies.
15 Good analysis in planning and prior to programming helps agencies to choose projects wisely and ensures that proper and adequate funds are budgeted for adaptation and other projects. It ensures scarce infrastructure dollars are not wasted. This is so important in Maryland that in 2017 Maryland DOT started combining their climate change, asset management, and traffic groups to be able to combine assessment in planning prior to programming. Framework Purpose â Closing the Gaps NCHRP 20-101 emphasizes the need to understand whether, when, and to what extent to incorporate adaptation measures. Adaptation projects or programs can involve a combination of engineering and operational measures, and transportation agencies have the opportunity to implement adaptations at a number of points in time, such as: ï· in advance of losses (hazard mitigation); ï· at the planning level â realizing impacts to infrastructure and costs to the public, choosing transportation and emissions trajectories/policies that minimize climate change or continue with business-as-usual; ï· at the project level; ï· as part of capacity expansion/capital improvement projects; and/or ï· during recovery, after losses have occurred. Although funding entities require different types of documentation in each of these scenarios, the proposed CBA framework would ideally be sufficiently flexible to accommodate the spectrum of projects or programs a transportation agency might develop. The study teamâs preferred approach was to integrate climate resilience into project and program planning by integrating a hazard mitigation-type CBA framework with a hybrid CBA framework encompassing both capacity expansion (considering the full lifecycle) and operational activities. The team identified three potential framework levels that could be further developed: 1. âLow Regretsâ Sketch-Level Resilience Analysis Framework is the least detailed and can answer the questions, âShould adaptation be considered at a certain location or in a region?â or âWould the public, infrastructure and the transportation system be better off on another path? Can we afford to continue on the climate change path? Should the DOT be looking for and implementing alternatives?â This goes beyond the information available in a vulnerability assessment by helping DOTs calculate a âback-of-the envelopeâ CBA. This approach would entail and rely on a significant number of simplifying assumptions. Unlike the other two options, this CBA approach is unable to provide insight about the role of timing in adaptation implementation. 2. Climate Resilience Framework requires moderate detail and can answer the question, âWhich combinations of adaptations are likely to increase resilience by reducing losses?â This approach can include incremental adaptations and phasing for operations-based strategies and facilitates considerations. 3. Detailed Engineering Resilience Analysis Framework is the most detailed and can answer the question, âHow resilient is this particular design under a variety of possible futures?â This approach has the most appeal for resilience assessment at the site- and project-specific level and has significant data requirements.
16 A prototype tool could also be developed to implement the selected framework and would be based on a flood hazard, as a significant amount of data and models are readily available to support development. During the Interim Meeting with the NCHRP 20-101 Advisory Panel, the members of the panel reviewed the information the research team provided and determined that developing the low regrets and climate resilience frameworks would be beneficial, but developing another tool was not in the best interest of practitioners at this time. Rather, they determined a simplified methodology that could be accomplished by hand would be more useful to practitioners. The panel decided that this approach would result in guidance that could be used more widely, and is necessary for agencies to evaluate their programs and adaptation options broadly. Framework Development The research team set out to develop two framework levels, with one building on the other. The sketch- level framework (Study Level 1 analysis) is intended to be useful for agencies with limited resources and/or data, or that want to conduct an initial screening to identify which assets warrant a more detailed evaluation of adaptation alternatives. The climate resilience framework (Study Level 2 analysis) builds on the sketch-level framework to evaluate the costs and benefits of different adaptation measures. The frameworks were developed with flooding in mind as the basis for development because the value of mitigation for flood loss avoidance is well documented. In addition, mapped floodplains correspond to the National Weather Serviceâs flood stage categories and are thus relevant to not only the asset management and operations and maintenance (O&M) perspectives, but also to the emergency management perspective. FHWAâs HEC-17, Highways in the River Environment: Extreme Events, Risk, and Resilience informed development of the frameworks, which are based on analysis Levels 1 through 3 as described in HEC-17. HEC-17 offers five levels of analysis with increasing complexity and accuracy for estimating future discharges: 1) Historical Discharges, 2) Historical Discharges plus Confidence Limits, 3) Precipitation Projection Trend Test, 4) Projected Discharges using CMIP Tool, and 5) Customized Projected Discharges with Climate Science. As the frameworks were developed, the research team looked for other ways to expand their applicability beyond flood hazards by considering data and climate models available to support analysis for adaptation to other natural hazard types. Because the frameworks use recurrence intervals as a basis for evaluation, they should be adaptable to other hazard types for which recurrence intervals exist or can be calculated. Recurrence intervals were used as the basis of evaluation because the design criteria commonly used for transportation facilities, including drainage work and flood control projects, is based on annual exceedance probability (AEP) and its reciprocal, the return period. The frameworks allow practitioners to complete an analysis based solely on financial considerations, or to incorporate environmental and social factors as well. Each framework considers the capital costs associated with the adaptation project, the associated operations and maintenance costs, and any costs that might be associated with delays to asset or corridor users during construction or other implementation of the measure. Benefits are primarily based on losses avoided, which could include physical damages, delays or loss of service to users, detours, and frequency of accidents. Environmental and social factors, such as reduction in greenhouse gas emissions, may also be considered.
17 A Study Level 1 analysis is an approximate test to see if it would be cost-effective to upgrade a transportation asset to accommodate climate change future conditions. The basic premise of this approach is that frequency-discharge relationship may change over time, but the frequency-damage relationship should remain constant. In other words, this approach assumes a given discharge, Q, will cause a given level of damage, D, regardless of climate change. However, the return period, T, associated with the given discharge of Q may be reduced due to climate change. This means that the resulting level of damage, D, will occur more frequently in the future than it does now. The goal of a Level 1 analysis is to determine how to improve the asset to maintain the frequency-damage relationship such that the same level of expected damages occurs under future flow conditions. For example, a practitioner might analyze the costs and benefits of adapting an asset that can handle the current 50-year flow to handle the future 50- year flow. A Level 1 analysis estimates a net present value for which adaptation actions would likely be cost-effective. A Study Level 2 climate resilience analysis builds on a Level 1 analysis and improves the accuracy of projected frequency-damage curves, accounting for life cycle costs and evaluating a benefit-cost ratio for an adaptation project under climate change conditions. In Study Level 2 analysis, the future damages considering climate change are calculated with and without adaptation measures in place. Transportation planners and designers are reminded that although design discharges and flood levels may increase under climate change scenarios in comparison to current conditions, facilities do not necessarily need to incorporate mitigation strategies against events with larger return periods. What it does mean is the same return period (i.e., same failure probability) will feature higher discharges and flood elevations. Ensuring the system will accommodate the increased discharges will make it resilient to the impacts of climate change. While the potential damages associated with a specific flood discharge will not change in the future (i.e., the damage-discharge relationship remains the same), the overall hazard level will increase if the same discharge will occur more frequently (i.e., smaller return period). Therefore, planners and designers must evaluate levels of acceptable risk and the event for which they will design based on that risk. For example, an asset that is critical to the system such that failure is unacceptable might be designed for an extreme event occurring at the end of its useful life, whereas a situation in which there is some level of acceptable risk might result in designing for the extreme event at 60 percent of the assetâs useful life and then re-evaluating at some point in the future when the incremental residual risk can be better predicted based on conditions at that time. The frameworks were evaluated in Chapters 7 and 8 of the accompanying guidebook using case studies from the HEC-17 manual and FHWAâs Climate Resilience Pilot program. A Study Level 1 CBA was applied to the data from the Minnesota Department of Transportation (MnDOT) Climate Resilience Pilot for Culvert 5648. The results of this screening-level analysis indicate a project costing less than approximately $1 million will be cost-effective when factoring in environmental and social benefits. A Study Level 2 CBA was completed for this same case study and found the proposed Option 1 to replace the culvert with a larger two-cell culvert would be cost-effective and have a benefit-cost ration (BCR) of approximately 1.65. Option 2, replacing the culvert with a 52-foot simple span bridge costing approximately $1.1 million, was found not to be cost-effective and have a negative BCR. These findings are consistent with those of the climate resilience pilot.
18 In addition, a Study Level 2 analysis was completed using data from HEC-17 for the Airport Boulevard Culvert. The results of the Study Level 2 analysis found the project to be cost-effective with a NPV of $11 million and a BCR of 7.43. These findings are reasonably consistent with those of the HEC-17 study, in which the project was found to have a NPV of $11 million and a BCR of 7.3. The frameworks were also applied to analyze the impacts of adaptation to sea level rise (SLR) to both a fictitious scenario in Galveston, Texas and the Maine DOT Climate Resilience Pilot study. Tide elevations were used in place of flows. These analyses can use projections from sea level rise calculators such as the U.S. Army Corps of Engineers (USACE) Sea Level Rise Curve Calculator or the SLR calculator developed for the Federal Transit Administration (FTA), or tide elevations can be interpolated based on known/estimated return periods for sea level rise flooding. The results of a Study Level 2 analysis for Route 1 in Scarborough, Maine found the proposed project to replace in-kind with 3.3 feet of SLR to be cost-effective. In addition to flooding and extreme precipitation, the research team found that extreme heat is also a significant concern to DOTs. Extreme heat can affect transportation assets by deforming pavement, stressing bridge joints and decks, and increasing cooling requirements for buildings and shelters. Extreme heat can also have significant health and safety impacts on workers, particularly those who construct and maintain transportation facilities, and system users (such as those who might have to wait at bus stops). This topic is relatively new, and while quantifiable information is becoming available regarding potential impacts on human health and safety, little information is publicly available that allows extreme heat impacts on transportation assets to be quantified. The general consensus is that transportation agencies first need to determine which question they need to ask: ï· Are they most concerned with operational impacts and costs, such as increases in energy usage and the associated costs due to increased demand for cooling, increased frequency of maintenance, etc.? ï· Are they most concerned about continuity of operations and the potential length and frequency of interruption if the power grid has stability issues during periods of excessive demand? ï· Are they most concerned with physical impacts to assets such as damage associated with deformation? Once a DOT determines which question they are most concerned with, they will need to evaluate the level of acceptable risk: can the function go offline for a while, and if so, for how long? If not, what must be done to ensure long-term functionality? Another concern regarding extreme heat is identifying if, when, and how adaptation might be needed for changes in hazard regimes. For example, some geographies that have not historically been subject to days exceeding 100 degrees Fahrenheit may experience several 100 degree days per year in the future under climate change conditions. Some chemicals and fuels used in the transportation industry have flash points near 100 degrees Fahrenheit, requiring special storage conditions in hot weather. Agencies that did not previously have this concern will, in the future, need to account for this essentially new hazard by implementing appropriate storage protocols, which could mandate changes to physical facilities as well as maintenance practices.
19 Because extreme heat events do not have associated recurrence intervals, traditional cost-benefit methodologies are not easily adapted to analyze them. While heating degree days and cooling degree days traditionally used in engineering design can be estimated in the future to reflect possible extreme heat events, accounting for humidity is more difficult because wet and dry bulb temperatures are not readily available in a format that architects and engineers can use. In an attempt to address this concern, the Transportation Engineering Approaches to Climate Resilience (TEACR) project conducted a case study in Texas to evaluate the impacts of changes in temperature and moisture on transportation asset performance. The study used the Thornthwaite Moisture Index (TMI), which is a dimensionless measure that indicates the humidity or aridity in a geographic region as a predictor of changes in humidity. The TEACR study correlates TMI with the various representative concentration pathway (RCP) scenarios in CMIP5 through 2100. This data could allow transportation practitioners to anticipate asset performance under changing temperature and precipitation and hence humidity conditions so they can determine if they should consider different design approaches, such as using a different asphalt binder in roads to decrease asphalt pavement rutting. Lifecycle costs can be computed based on scenarios to evaluate the impacts of extreme heat on transportation assets and potential adaptation options, and the results compared to evaluate cost- effectiveness; however, traditional benefits are more difficult to quantify. If the question of concern relates more to continuity of operations, an economic impact analysis of an asset or system outage could be useful to DOTs in decision-making processes regarding adaptation for extreme heat.