Translating Dreams into Reality:

Transcription

1 Translating Dreams into Reality: Assessing risk in an unpredictable world Surge from Hurricane Sandy crashes over a sea wall in Kennebunk, Maine on October 29, 2012 Judy Gates, Director, Environmental Office Maine Water and Sustainability Conference, March 31, 2015

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3 Northeast Observed Change in Heavy Precipitation National Climate Assessment 2014

4 100-year precipitation event Capacity Current precipitation yr event Current precipitation Pipe lifespan Appropriate planning horizon?

5 The Lingo Capacity = ability to convey precipitation; based on familiar hydrology Resiliency = ability to withstand precipitation, sea level rise, storm surge; paradigm shift Criticality = function, e.g. emergency access, traffic volume, detour availability Vulnerability = exposure, sensitivity, adaptive capacity Green Infrastructure = using natural resources to protect built infrastructure Risk = [probability of event x probability of failure] x consequences

6 IMPLEMENTATION PLANNING Image courtesy of Renjith Krishnan at FreeDigitalPhotos.net

7 All we have to do Consider lifecycles and context in planning and design decisions to make even-handed, risk-based, consistent decisions at a predictable cost.

8 USACE Stream Mitigation FHWA Climate Resiliency Grants MaineDOT 3-year Work Plan MAP-21 Risk-based asset management Permit by Rule Updates? EO Flood-risk based management standard Eco-Logical & SHRP2 Landscape scale effects assessment FHWA Order 5520 Climate and extreme weather resiliency USACE Maine General Permit Expires October 2015 Maine Stream Barrier Assessment Sustainability Solutions Initiative FEMA Disaster Mitigation Program USACE Silver Jackets Report FEMA Public Assistance Program Gulf Coast Study Part 2

9 FHWA Order 5520 Transportation System Preparedness and Resilience to Climate Change and Extreme Weather Events December 15, 2014 EO (modifies EO 11988) Establishing a Federal Flood Risk Management Standard and a Process for Further Soliciting and Considering Stakeholder Input January 30, 2015

10 Engineering Project Timeline Benefit-Cost Analysis $ Benefit-Cost Analysis $ Design Build $ Planning

11 What the conversation is really about When will the next big storm hit? How do we know what to protect first? How much risk can we tolerate? What do customers expect? How much will it cost? Who is going to tell us how to engineer our way out of this?

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13 Elevation Basis of COAST New exceedance curves for future (i.e. how likely is a 10-yr storm to occur?) Exceedance curve based on FEMA flood studies Probability

14 Using the lingo 1. Identify vulnerable infrastructure 2. Select critical transportation structure 3. Develop a Decision Support Tool (DST) to rank asset priorities within each town 4. Run highest priority assets through T-COAST scenarios 3 bridges 2 culverts 1 road 5. Pick most cost-efficient, resilient alternative

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17 CRITICALITY VULNERABILITY DST Data needs 1. Feet of freeboard under bridge between lowest chord and 100 yr BFE or road segments < 5 ft above 100 yr BFE 2. % of bridge length at height of lowest chord or degree culverts/drainage structures are prone to failure during rain/tidal storm events 3. Approaches flood or road included in TIP for rehab or reconstruction 4. Scour critical 5. NBIS score > 5 or road surface asphalt or concrete 6. Functional classification of roadway 7. Utilities/other modes associated with bridge or road 8. Roadway is identified evacuation route 9. Hospital, emergency access way?

18 New Question: What asset to you worry about during a storm? ME Route 209, south of Sam Day Hill Rd, Phippsburg ME Route 127, at Sequinland Rd, Georgetown ME Route 1 over Scarborough Marsh, Scarborough New Meadows Rd on Old Bath Road, Bath ME Route 25, Bowdoinham Meadow Rd, Topsham

19 Methods Key elements of the approach: For each asset, the software analyzed cost-benefit relationships of three alternatives: Replace to current design standards Replace with structure built to standards for 3.3 of SLR Replace with structure built to standards for 6.6 of SLR

20 Methods Key elements of the approach: For each asset, the software analyzed cost-benefit relationships of three alternatives: Replace in-kind Replace with structure built to standards for 3.3 of SLR Replace with structure built to standards for 6.6 of SLR In general: Costs: Initial replacement or construction costs Maintenance and repair over time, after each storm surge event Benefits: Avoided damages provided by each structure in the face of a range of SLR and storm surge scenarios tallied cumulatively over time.

21 Depth Damage Functions Designed for Each Structure Elev. Damage Cost Extreme = $E/event Bridge cord height Severe = $D/event 8-11 Moderate = $C/event 7-8 Minor = $B/event 0-7 Slight = $A/event Waterway Base Elevation

22 Scarborough Low Sea Level Rise (3.3') Initial Construction Costs Total Damage/Repair Costs by 2100 TOTAL LIFE CYCLE COST BY 2100 Replace in Kind $3,600,000 $ 349,128 $3,949,128 Replace with 3.3' SLR design $4,300,000 $ 181,330 $4,481,330 Replace with 6' SLR design $6,000,000 $ 3,323 $6,003,323 High Sea Level Rise (6') Initial Construction Costs Total Damage/Repair Costs by 2100 TOTAL LIFE CYCLE COST BY 2100 Replace in Kind $3,600,000 $ 823,325 $4,423,325 Replace with 3.3' SLR design $4,300,000 $ 642,948 $4,942,948 Replace with 6' SLR design $6,000,000 $ 69,547 $6,069,547

23 Bath Low Sea Level Rise (3.3') Initial Construction Costs Total Damage/Repair Costs by 2100 TOTAL LIFE CYCLE COST BY 2100 Replace in Kind $ 400,000 $697,476 $1,097,476 Replace with 3.3' SLR design $ 594,000 $697,476 $1,291,476 Replace with 6' SLR design $1,000,000 $281,242 $1,281,242 High Sea Level Rise (6') Initial Construction Costs Total Damage/Repair Costs by 2100 TOTAL LIFE CYCLE COST BY 2100 Replace in Kind $ 400,000 $1,867,580 $2,267,580 Replace with 3.3' SLR design $ 594,000 $1,867,580 $2,461,580 Replace with 6' SLR design $1,000,000 $ 916,598 $1,916,598

24 Bowdoinham Initial Construction Costs Low Sea Level Rise (3.3') Total Damage/Repair Costs by 2100 TOTAL LIFE CYCLE COST BY 2100 Replace in Kind $250,000 $1,656,830 $1,906,830 Replace with 3.3' SLR design $394,000 $1,162,080 $1,556,080 Replace with 6' SLR design $491,000 $ 205,159 $696,159 Replace with 6' SLR design $491,000 Initial Construction Costs High Sea Level Rise (6') Total Damage/Repair Costs by 2100 TOTAL LIFE CYCLE COST BY 2100 Replace in Kind $250,000 $2,163,283 $2,413,283 Replace with 3.3' SLR design $394,000 $1,900,813 $2,294,813 Replace with 6' SLR design $491,000 Replace with 6' SLR design $491,000 $ 908,565 $1,399,565

25 Back to that conversation Q: When will the next big storm hit? A: Next week, next decade, next century Q: How will we know what to protect first? A: Use the best data and know-how available Q: How much risk can we tolerate? A: It depends who is footing the bill Q: What do customers expect? A: 100% accessibility, 100% of the time Q: What will it cost? A: too much zip, zero, zilch wiggle room Q: Who is going to tell us how to engineer our way out of this? A: Not it

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27 Insanity Doing the same thing over and over again and expecting different results. Albert Einstein

28 Current Practices Bridges: Culverts: 90% full at Q50 Check that Q100 runs full, but not over road surface Check scour to Q500 Sized for Q50 90% full at Q50 Full at Q100 Check 1.2 bank full width

29 Back to our friend Albert You can t solve a problem at the same level of consciousness that created it. Albert Einstein

30 Getting at context and opportunity Surrounding landscape (e.g. land cover, topography) Flood potential Ecosystem services (current and potential) Debris potential (e.g. large woody debris, bed load) Risk of failure (e.g. condition ratings)

31 Route 2, Mercer

32 Route 4, the Berwicks

33 A few pesky realities Can t throw the baby out with the bathwater Can t love the new baby more Uncertainty is a fact of life Data will always be incomplete Money will always be a limiter Analysis paralysis is not effective asset management It only takes a small adjustment to avoid the iceberg

34 The road ahead See opportunity in necessity Risk resistant is the goal, not risk-proof no regrets decision-making Understand that everything relies on benefit:cost Lack of catastrophe breeds complacency Be clear that not getting in the way is not the same as helping The eaten by wolves factor

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