1. MnDOT Flash Flood Vulnerability and Adaptation Assessment Pilot Project January 2015

2. Project Background Minnesota GO Vision & Statewide Multimodal Transportation Plan identified the risk of flash flooding as a result of changing precipitation patterns due to climate change. From 1958 to 2011, 45% increase in very heavy precipitation in the Midwest (NOAA)

3. MnDOT’s Pilot Project Objectives Better understand the trunk highway network’s risk from flash flooding Identify cost-effective options to improve the network’s resiliency Support MnDOT’s asset management planning Provide feedback to FHWA on the Draft Framework

4. Funded by FHWA Climate Change Resilience Program Program Goals: Advance transportation climate resilience activities Assist FHWA in building the Vulnerability Framework into an Adaptation Framework Funded 5 pilot projects in 2010-2010 to test an assessment conceptual model Funded 19 pilot projects, including Minnesota, in 2013 as part of an effort to test the Framework 4

5. Project Roles and Responsibilities Consultant:

6. Pilot Project Overview Phase 1: System-wide vulnerability assessment – High-level screen of trunk highway network in Districts 1 & 6 Phase 2: Facility-level adaptation analysis – Two high risk facilities (one in each district)

7. Defining Vulnerability “Climate change vulnerability in the transportation context is a function of a transportation system’s exposure to climate effects, sensitivity to climate effects, and adaptive capacity.” (Vulnerability Framework) Exposure- whether the asset or system is located in an area experiencing direct impacts of climate change Sensitivity - how the asset or system fares when exposed to an impact Adaptive capacity - the systems’ ability to adjust or cope with existing climate variability or future climate impacts

8. Systemwide Vulnerability Assessment Approach

9. Criteria Weighting Example: Culverts Sensitivity Exposure Adaptive Capacity

10. Number of Assets Scored Bridges Large Culverts Pipes Roads Paralleling Streams (segments) Total District 114016054318 861 District 617636137744 958 Total316521920621,819

11. Highly vulnerable (Tier 1 and 2) assets are not necessarily in imminent danger of flooding, nor are lower vulnerability assets immune from flooding. Values are indicators of relative vulnerability compared with other assets in the same district.

13. Vulnerability By Asset Type District 6 District 1

14. Vulnerability By Asset Type District 1 District 6

16. 1.Describe the site context 2.Describe the facility 3.Identify climate stressors - Heavy precipitation 4.Develop climate scenarios (Low, Medium, High) 5.Assess performance of the facility 6.Identify adaptation options – Meet MnDOT 50-year clearance guidance – Meet FEMA 100-yr floodplain impact regulations 7.Assess performance of the adaptation options 8.Conduct an economic analysis 9.Evaluate additional considerations 10.Select a course of action 11.Plan and conduct ongoing activities Adaptation Assessment General Approach

17. Adaptation Analysis Case Study Example

18. Culvert 5722 Crosses Spring Valley Creek south of Rochester Drainage Area: 14 mi 2 AADT 5,700 Detour: 0.6 miles Floods at current 10 year storm District 6 – Spring Valley Creek

19. 24-Hr Storm Return Period Atlas 14 Precip. Depth (in) Low Scenario Precipitation Depth (in) Medium Scenario Precipitation Depth (in) High Scenario Precipitation Depth (in) 204020702100204020702100204020702100 2-yr storm2.792.802.81 2.943.043.153.013.213.46 5-yr storm3.73.723.73 3.873.984.094.144.615.11 10-yr storm4.494.524.534.544.684.814.955.306.167.07 25-yr storm5.695.735.765.775.946.106.276.938.249.66 50-yr storm6.76.766.796.817.007.207.418.229.8311.61 100-yr storm7.817.907.947.968.188.438.699.5811.4513.59 500-yr storm10.810.9711.0511.1011.4011.8012.2312.9615.3318.25 Projected Climate Conditions

20. Adaptation Options: Culvert 5722 Base: Replace in-kind – Construct cost: $460,000 Option 1: Add 2 6’x10’ culvert cells to existing design – Construction cost: $690,000 Option 2: same as option 1 + floodplain enhancement – Construction cost: $1,130,000 Option 3: Replace Culvert three span 84-foot long bridge – Construction cost: $4,210,000

21. COAST Model Option 1 Construction Cost

22. Cost Effectiveness: Culvert 5722 Without Social CostsWith Social Costs Social costs include safety and detour costs Discount Rate: 2.0%

23. Conceptual Adaptation Screening Framework

24. Lessons Learned Data availability/accuracy/consistency System-level screen is possible Build more time for variable weight discussion/ sensitivity analysis Adaptive capacity needs more discussion Adaptation doesn’t have to be scary – might be more incremental

25. Next Steps – Complete assessments in other districts and/or other types of “assets” (i.e. slopes) – Explore partnerships with floodplain managers to develop real-time monitoring and warning systems for tier 1 and 2 assets – Incorporate considerations of risk into ongoing culvert and bridge improvement programs – Incorporate scores into asset management databases and the asset management plan

26. QUESTIONS? www.mndot.gov/climate Project Contact: Philip Schaffner Policy Planning Director MnDOT Office of Transportation System Management philip.schaffner@state.mn.us philip.schaffner@state.mn.us 651-366-3743