Culvert Risk Mitigation Planning - Transportation.org...2019/08/09 · Proposed Culvert Mitigation...
Transcript of Culvert Risk Mitigation Planning - Transportation.org...2019/08/09 · Proposed Culvert Mitigation...
Culvert Risk Mitigation Planning
Lizzie Kemp, CDOT Resiliency Program Manager
August 29, 2019
AASHTO CTSSR Meeting
1. Background – Why a mitigation plan for minor culverts?
• CDOT Resiliency Program
• I- 70 Risk and Resiliency Pilot
• Prioritizing Risks Based on Study Results
2. Method for Identifying Highest Risk Minor Culverts
3. Goal: Developing a Mitigation Plan for Highest Risk Culverts
Overview
CDOT Resiliency Program
Lessons Learned
1976 and 2013 floods destroyed many of the same facilities
What can we do now ….
… To avoid this in the future?
Colorado Resiliency Framework
Created by the Colorado Resiliency Office (DOLA)
Defines re·sil·ience for Colorado
“The ability of communities to rebound, positively adapt
to, or thrive amidst changing conditions or challenges—
including human-caused and natural disasters—and to
maintain quality of life, healthy growth, durable systems,
economic vitality, and conservation of resources for
present and future generations.”
CDOT Resiliency Program
• Created in 2018, with Policy Directive
1905.0 – the vision for resilience at CDOT
• Works to integrate resilience in CDOT
functions
• Coordinates resilience activities at CDOT
• Conducts research to support resilience
• Provides resilience knowledge and
resources to CDOT staff
I 70 Risk and Resiliency Pilot
I-70 Corridor Risk & Resiliency Pilot
• Analysis of risk potential from physical threats on I-70 from Kansas to Utah
• Looked at – all assets – roads, bridges, culverts, etc.– Wide range of threats – flood, avalanche,
rockfall, etc.
• Proactive look at optimal investments we can make now, in advance of future events, to improve system resilience
• Builds on the 7-step RAMCAP process utilized in flood recovery effort
I 70 Pilot Results
Asset Criticality – Some Roadways are More Critical Than Others
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• Usage: AADT + Roadway Classification
• Economic Impact: Freight value ($) + Tourism value ($)
• Social Impact: SoVI
• System Impact: System Redundancy
Equal weight assigned to each of the six selected variables.
SOCIAL ENVIRO ECON
✓ ✓ ✓
✓
✓
✓ ✓ ✓
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Criticality Map for System Resilience
AADT 16.7%ASHTO Road Classification 16.7%Freight $ (County) 16.7%Tourism $ (County) 16.7%SoVI 16.7%Redundancy 16.7%
Reminder: Criticality reflects the importance of each asset to overall operations within CDOT’s network as related to system resilience only. Criticality is part of Step 1 in a 7-step Risk and Resilience Analysis process.
Equal Weight
53.8% Low
25.5% Moderate
20.7% High
Consequence Analysis ($ per threat-asset pair)
Given the worst reasonable event, what are the consequences? ($)
Owner Cost• Asset Replacement
Cost
User Cost• Value of time
(delay/detour)
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Prioritizing Which Risks to
Mitigate
Prioritizing I 70 High Risk
Assets
• Highest owner risk on all of I-70 is rockfall (63%). Rockfall also presents a pretty big portion of the corridor wide user risk (22%).
• Flood is the largest corridor user risk (72%) with most of that related to minor culverts (80%).
• Direction from Executive Committee –Focus first on Rockfall and Minor Culverts
I 70 Pilot Results
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$6,136,494
$164,667,186
$-
$20,000,000
$40,000,000
$60,000,000
$80,000,000
$100,000,000
$120,000,000
$140,000,000
$160,000,000
$180,000,000
Owner Risk (OR) User Risk (UR)
All Threats
Owner Risk (OR) User Risk (UR)
User Risk -- Share of Each Threat
Flood $118,190,629 Rockfall $35,781,405 Avalanche $8,516,650
Landslide $2,161,863 Wind $9,738 Bridge Strike $6,901
$-
$20,000,000
$40,000,000
$60,000,000
$80,000,000
$100,000,000
$120,000,000
ApproachFlood
BridgeFlood
MinorCulvertFlood
NBI CulvertFlood
Road Flood Wall Flood
User Risk Related to Flood
Prioritizing At Risk Culverts
• With nearly 60,000 culverts under 4 feet across the state, which subset should we create a maintenance plan for first and when should the plan be completed?
• Proposal: Focus first on culverts in poor condition that are also on critical routes
• First Tier (approx 18 k)– culvert scores 6-9 plus all unrated Target completion -- ?
• Second Tier (approx 14.5 k) – culvert scores 3-4 Target completion -- ?
• Third Tier (approx 24 k)- culvert scores 1-2 – no plan, accept the risk?
GIS At Risk Culverts tool
• Created by Gerry Shisler, CDOT GIS Team
• In development – data available statewide
• Able to identify culverts and their condition and whether they are located on “critical” roadways
CULVERTS CONDITIONS,LESS THAN 48” (4 FEET)TOTAL = 54,716 PIPES
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Criticality Map for System Resilience
AADT 16.7%ASHTO Road Classification 16.7%Freight $ (County) 16.7%Tourism $ (County) 16.7%SoVI 16.7%Redundancy 16.7%
Reminder: Criticality reflects the importance of each asset to overall operations within CDOT’s network as related to system resilience only. Criticality is part of Step 1 in a 7-step Risk and Resilience Analysis process.
Equal Weight
53.8% Low
25.5% Moderate
20.7% High
CULVERTS CONDITION POORHIGHWAY CRITICALITY HIGH
Proposed Culvert Mitigation Plans
Step 1: maintenance patrols complete an inspection of identified high-risk culverts (update condition in database)
Step 2: identify and document specific proposed mitigation action for each culvert based on inspection
* e.g. replace culvert, slip line, etc.
Step 3: if no mitigating treatment is possible or is too costly, identify and document a specific operations plan
* e.g. increased cleanout frequency, install technology to monitor flows, etc.
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HIGHWAY CRITICALITY
ONLY POOR CONDITION CULVERTS
Extra slides
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COLOR MATRIX
Three vehicles lie in a creek after raging
floodwater undercut Dillon Road near
U.S. 287 in Broomfield on Sept. 12,
2013. The three motorists were rescued
after emergency workers secured the
vehicles with ropes and the motorists
scrambled up the banks of the creek.
Credit: Andy Cross, The Denver Post
The 2013 Flood Was…
A Human
Disaster
• 10 fatalities
• 28,000 people force from home
• 2nd largest airlift in U.S. History
• 32 CDOT Permanent Repairs
required
The 2013 Flood Was…
A Costly
Disaster
• $555 billion impact to economy
• $4 billion in total damages statewide
• $736 million damage to infrastructure
– $130 million Emergency Repair
– $616 million Permanent Repair
– $708 from FHWA Emergency Fund
I-70 Corridor Risk & Resilience Pilot
• “Pilot” the data, assumptions, and methodology needed to quantify:– What are CDOT’s assets?
• Location, value, condition, criticality
– What are relevant physical threats?• Likelihood and location
– What impact would they have on our system?• Consequences and vulnerability
– What are the optimal investments we can make now to improve resiliency in advance of future events?
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Key Concepts – Risk Definition
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Risk (R) C x V x TRisk (R) ($) Potential cost of asset losses in a threat-filled environmentConsequence (C) ($) Result of asset failureVulnerability (V) (%) Susceptibility to the threatThreat Likelihood (T) (%) Potential of threat occurrence
Risk – potential cost of losses to CDOT assets (direct and indirect)Resilience – ability to remain functional even in presence of risks
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Threats Assets
Avalanche Bridges
Flood (scour) Bridge Approaches
Flood (Overtopping / debris) Roadway Prism
Fire (wildland) Post Tension Concrete Slabs
Landslide Tunnels
Rockfall NBI Culverts
High wind (special wind zone)
Minor Culverts
Tornado Walls
Bridge strike ITS Devices