The National Academies Press

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From page 68... ... 68 Introduction to Levels of Analysis Historically, many DOTs have used CBA only for large or complicated projects; however, with increased emphasis on asset management planning, transportation practitioners increasingly recognize that CBA would be useful in design and planning. They also realize that CBA could be applied to a betterment decision on an FHWA ER project, but CBA is generally regarded as cumbersome and costly, and transportation practitioners are reluctant to undertake the analysis for decisions regarding smaller capital projects. Read the entire page →
From page 69... ... Study Level 1 Climate Resilience Cost-Benefit Analysis 69 cases, designing for the absolute worst case scenario might not be cost-effective, as discussed in Box 3. Flooding is one of the most frequent and costliest natural hazards to damage transportation assets and systems, as well as one of the natural hazards likely to be most affected by climate change; average annual flood losses in the five most at-risk cities in the United States are expected to be approximately $8 billion by 2050 (Hallegatte et al., 2013) Read the entire page →
From page 70... ... 70 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change -- Guidebook non-stationarity. HEC-17 offers five levels of analysis with increasing complexity and accuracy for estimating the future discharges: 1. Read the entire page →
From page 71... ... Study Level 1 Climate Resilience Cost-Benefit Analysis 71 Process Walk-Through with an Example for Riverine Flooding Select Data Inputs and Data Sources Establish Base Conditions Study Level 1 analysis is basically an approximate test to see if it would be cost-effective to upgrade the hydraulic structure for the future conditions posed by climate change. The central point in this approach is that a given discharge, Q, will cause a given level of damages, D, with or without climate change. Read the entire page →
From page 72... ... 72 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change -- Guidebook occurring more often (Figure 21) Read the entire page →
From page 73... ... Study Level 1 Climate Resilience Cost-Benefit Analysis 73 are included in HEC-17, Chapter 7, such as Rational Method, Unit Hydrograph, and the Natural Resources Conservation Service's Peak Graphical Method. Read the entire page →
From page 74... ... 74 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change -- Guidebook 7. Use Equation 12 to calculate the total annualized damages, which is the sum of Dacmod and Dacmax: Equation 12. Read the entire page →
From page 75... ... Study Level 1 Climate Resilience Cost-Benefit Analysis 75 start by identifying the climate change scenario or level of risk to be used for analysis (see Chapter 3 in this guidebook and Chapters 4–6 in HEC-17) Read the entire page →
From page 76... ... 76 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change -- Guidebook Figure 23. Peak discharge and associated damages under current conditions for example project. Read the entire page →
From page 77... ... Study Level 1 Climate Resilience Cost-Benefit Analysis 77 for the base flow (in this example, approximately 33 years) Read the entire page →
From page 78... ... 78 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change -- Guidebook 6. Calculate the annualized damages with climate adjustment using a similar approach to Equation 10, substituting the climate-adjusted values for the current condition values. Read the entire page →
From page 79... ... Study Level 1 Climate Resilience Cost-Benefit Analysis 79 This value represents the additional present value of the expected damages from climate change during the remaining bridge useful life. A hazard mitigation or resilience measure aimed at maintaining the current frequency-damage structure (design level) Read the entire page →
From page 80... ... 80 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change -- Guidebook Figure 26. MnDOT evaluated Culvert 5648 for cost-effective adaptations to climate change (MnDOT, 2014) Read the entire page →
From page 81... ... Study Level 1 Climate Resilience Cost-Benefit Analysis 81 MnDOT used a software tool called SimCLIM to evaluate future projections for three precipitation scenarios: RCP 4.5, RCP 6.0, and RCP 8.5. All three scenarios considered 24-hour precipitation depths. Read the entire page →
From page 82... ... 82 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change -- Guidebook Depth-damage data and a depth-damage curve were provided for Option 1. Because no data were available for the base case, the Option 1 data were applied to base conditions as well. Read the entire page →
From page 83... ... 628.00 626.00 624.00 622.00 620.00 618.00 616.00 614.00 612.00 Base Case Option 1 Option 2 Option 3 610.00 608.00 606.00 7,000 1,000 0 2,000 3,000 4,000 5,000 6,000 Flow Rate (cfs) H ea dw at er E le va tio n Low Point El. Read the entire page →
From page 84... ... 84 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change -- Guidebook This means that the in-kind replacement culvert is expected to sustain damages totaling $90,698 over its useful life of 80 years under current climate conditions. Next the analysis was adjusted to account for climate change. Read the entire page →
From page 85... ... Study Level 1 Climate Resilience Cost-Benefit Analysis 85 Multiplying $10,052 by the present value coefficient of 39.745 results in total damages of $399,517. So, the expected damages over the life of an in-kind replacement culvert under the medium scenario climate change conditions will be approximately $399,517. Read the entire page →
From page 86... ... 86 Incorporating the Costs and Benefits of Adaptation Measures in Preparation for Extreme Weather Events and Climate Change -- Guidebook 11. For the selected gauge and project useful life duration, find the adjusted return period under SLR conditions for the flood elevations used to establish current conditions (i.e., Tide Elcnd, Tide Elcmod, and Tide Elcmax) Read the entire page →
From page 87... ... Study Level 1 Climate Resilience Cost-Benefit Analysis 87 The 50-, 100-, and 500-year recurrence interval information for current conditions was used to reflect current pre-resilience conditions. These recurrence intervals were selected because the adaptation/resilience project is intended to protect against the current 500-year event. Read the entire page →

From page 68...

... 68 Introduction to Levels of Analysis Historically, many DOTs have used CBA only for large or complicated projects; however, with increased emphasis on asset management planning, transportation practitioners increasingly recognize that CBA would be useful in design and planning. They also realize that CBA could be applied to a betterment decision on an FHWA ER project, but CBA is generally regarded as cumbersome and costly, and transportation practitioners are reluctant to undertake the analysis for decisions regarding smaller capital projects.