Halcrow.com Risk-Based Coastal Asset Management Adam Hosking Louise Trim Ben Hamer Richard Harpin Gulf Coast Hurricane Preparedness, Response, Recovery

halcrow.com

Risk-Based Coastal Asset Risk-Based Coastal Asset ManagementManagement

Adam Hosking

Louise Trim

Ben Hamer

Richard Harpin

Gulf Coast Hurricane Preparedness, Response, Recovery & Rebuilding Conference. Mobile, AL. November 11-14, 2008

Gulf Coast Hurricane Preparedness, Response, Recovery & Rebuilding Conference. Mobile, AL. Nov. 11-14, 2008

Outline

• UK Strategic Risk Analysis

• Applications of approach

• Asset Management System

• Conclusions


Strategic Risk Analysis in the UKStrategic Risk Analysis in the UK


Risk Management - Background

• In UK 5 million people in 2 million homes live in flood risk areas

• Over 120,000 residential and commercial properties at erosion risk

• Significant geographic variation • Widespread flooding experienced in 1998 and 2000

• “Lessons Learned” led to an enhanced emphasis on flood risk management

UK Government Flood & Erosion Risk Management Objective:

In order to ensure the best use of public money, target spending in those areas of greatest flood risk, whilst seeking to maximise the return

on investment in terms of reduction of flood risk.


Risk Assessment for Strategic Planning (RASP)

(HR Wallingford, 2001)

www.rasp-project.net

• Structured approach to the analysis and management of the

flooding system

• Focus on risk, explicitly recognising that defences and flood

plains perform as ‘systems’


Analysis Philosophy

• Performance of flood risk structures represented as ‘fragility curves’

• Relates loading on an asset to the conditional probability of failure of that asset given that loading.


Predicting to flooding pathway

True Fragility Curve

RASP

• Based on: field inspections, empirical models, limit state equations, expert judgement

• Developed for approx. 60 generic asset types


Asset Condition Grades

• Five condition grades

• Based on asset performance, not just traditional condition.


Load

Probability

SourceProbability of failure

Load

Pathway

PathwayDamage

Receptor

Depth

The Analytical Approach

www.rasp-project.net


Performance-based Asset Management System (PAMS)

PAMS project:

• Developing performance-based approach to identifying and prioritizing management of flood defences

• Ongoing studies, including:

– Improved failure mode analysis to determine key performance features, and hence condition grade

– Local applications to determine site specific fragility curves

www.pams-project.com

Assess for control structure condition

Condition = 5Condition = 4Condition = 3Condition = 2Condition = 1

None

Damage to walings, ties or

fixings?(b*)

Evidence of damage to or absence of

planks?(a*)

Wednesday, 27 February 2008

Asset Type = Beaches Performance Feature = Condition of control structures (timber)

B4a

Notes:

(a*)Severe = Substantial loss of or damage to planks significantly reducing arrest of beach material drift.Minor = Minimal damage to, loss or absence of planks. Groyne still ensures arrest of majority of beachmaterial drift.

(b*)Severe = Significant damage or loss of ties, walings and fixings affecting structural integrity of structureMinor = Minimal structural damage to ties, walings or fixings not affecting structural integrity of structure

No

Severe

Structure still able to arrest sediment drift?

Yes

Minor

No

Partly

Damage to walings, ties or

fixings?(b*)

MInor

SevereNone

Minor

Severe


Applications of approachApplications of approach


Tiered Approach

Level Decisions to inform Data sources Methodologies

High National assessment of economic risk, risk to life or environmental risk

Prioritisation of expenditure

Regional planning

Flood warning planning

Defence type

Condition grades

Standard of Protection

Indicative flood plain maps

Socio-economic data

Land use mapping

Generic probabilities of defence failure based on condition assessment and crest freeboard

Assumed dependency between defence sections

Empirical methods to determine likely flood extent

Intermediate Above plus:

Flood defence strategy planning

Regulation of development

Maintenance management

Planning of flood warning

Above plus:

Defence crest level and other dimensions where available

Joint probability load distributions

Flood plain topography

Detailed socio-economic data

Probabilities of defence failure from reliability analysis

Systems reliability analysis using joint loading conditions

Modelling of limited number of inundation scenarios

Detailed Above plus:

Scheme appraisal and optimisation

Above plus:

All parameters required describing defence strength

Synthetic time series of loading conditions

Simulation-based reliability analysis of system

Simulation modelling of inundation

(HR Wallingford, 2002)


Application of RASP

• Set-up within GIS

• National Assessments:– 2002, 05, 06 & 08

– 2004 Foresight Future Flooding

• Used to inform policy and decision making

• Provide consistent national flood risk mapping (public access)

• Local scale assessments:

– Project development

– Assist in the planning maintenance and replacement of assets


Asset Management SystemAsset Management System


• Based on existing GIS data platform (SANDS)

• Import, visualize and manipulate asset data• Basis for consistent data capture

• Record asset types and condition, hence fragility

• Identify asset systems

• Link assets to risk areas and receptors

• Use cost models to optimise investment strategies

Asset Management System (AMS)


1. Base mapping

2. Asset inventory

3. Relationship between loading and asset condition (fragility curve)

4. Cost models for upgrading from different condition grades (hence improving performance) for a given asset type

5. Flood extent and receptor data

Key Components of System


System Components


System Components


System Components


System Components


System Components


System Components


• Use of optimization engine to automate decision-making

• Tool to provide user with top ten outcomes (against multi-criteria objectives), to enable considered selection of preferred option

• Possible development for use at higher, regional & national level to inform policy makers and budget setters

Ongoing Development


• Benefits of Risk-based Asset Management:

– provides for systematic and co-ordinated approach to asset management

– requires comprehensive asset information (facilitates collection)

– focus on asset function and reduction of risk

– avoid surprises (physical or financial)

– evidence-based decision-making

Conclusions

• AMS benefits:

– built on established database platform

– consistent data storage and analysis

– facilitates improved decision-making

– maximize risk management benefits from finite budgets

halcrow.com

THANK YOU!THANK YOU!

Adam HoskingAdam HoskingHalcrow Inc, Tampa, FLHalcrow Inc, Tampa, FL

Tel:Tel: (813) 876 6800 (813) 876 6800

Email: Email: [email protected]@halcrow.com

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Halcrow.com Risk-Based Coastal Asset Management Adam Hosking Louise Trim Ben Hamer Richard Harpin Gulf Coast Hurricane Preparedness, Response, Recovery