hr wallingford ltd 2002 overview of the cfmps and the mdsf rob cheetham hr wallingford ltd
TRANSCRIPT
HR Wallingford Ltd 2002
Overview of the CFMPs and the MDSF
Rob Cheetham
HR Wallingford LTD
HR Wallingford Ltd 2002
INTRODUCTION
The following presentation aims to give:
•a brief overview of Catchment Flood Management Planning (CFMPs) and the Modelling and Decision Support Framework (MDSF)
•show methods of developing catchment wide rainfall runoff and flow routing models
•Demonstrate how to carry out socio-economic impact analysis within the MDSF
•Show how “what-if” scenarios can be developed to address policies
HR Wallingford Ltd 2002
PURPOSE OF CFMPs
• To determine the socio-economic risks associated with flooding;
• To investigate the efficacy of different flood management in reducing unacceptable risk at a catchment scale;
• To provide the basis for sustainable flood management policies within each catchment over the next 50 years.
PURPOSE OF MDSF
• To support implementation of CFMPs
•To provide tools to aid socio-economic and uncertainty analysis
• Manage data and results of “what if” scenario testing
HR Wallingford Ltd 2002
HR Wallingford Ltd 2002
Scoping Study dataSteps 1 and 2
Existing conditionsdatabase
Steps 3, 4 and 8
Flood extent anddepthStep 7
Economic and socialimpactsStep 9
Policy evaluation forexisting conditionsand future scenarios
Steps 9&10
Flood damage andsocial impact tools
Flood mapgeneration tools
Flow routing tool
Hydrology tool
Uncertaintyestimation procedure
TOOLKIT
Scenario definitionStep 5
CFMPStep 11
MDSF SYSTEM
CUSTOMISEDGIS
Figure 3.1 MDSF System
Note: Step numbers refer to steps inCFMP methodology
Flows, levels andflood duration.
Steps 4 & 6
Sensitivity tests:scenarios and storage
CASE MANAGEMENTFRONT END ANDUSER INTERFACE
CORE DATA- OS Background- Flood maps- Flood defences- Topography- Land use- Environmental- Social information- Existing reports- etc
Local orcatchment-specificdata
SECTION 105MAPS &MODELS
CFMP OUTPUTS(Electronic
CFMPs)
AGENCYDATABASES
PROCEDURES
MDSF system diagram
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Import base data
HR Wallingford Ltd 2002 Downstream boundary
Croal/Tonge confluence
Upstream boundary
Farnworth GS
Section 105 hydraulically modelled reaches
Routeing modelling
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Sub-catchment 1-9 FEH lumped catchment
Sub-catchment 1-9i (intermediate sub-catchment)
Sub-catchment 1-6
Linked with rainfall runoff model
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Import water levels and hydrographs
HR Wallingford Ltd 2002External model results
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Economic damages
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Social vulnerability
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• Rainfall runoff - routing model generates water levels for present and future conditions
• MDSF generates flood outlines and socio-economic impacts, thus defining the present and likely future flood risks
• THESE ARE THE BASE CONDITIONS
• Policies are developed to address flood risks
• In the following example, the policy for the Croal catchment is ‘ensure River Tonge water levels do not increase in the future for the 100-year event’
Policy development
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• Flood management options are developed to try to achieve the policy
• Each option consists of a set of measures
• Flood management measures include:
– On-line/off-line storage
– Flood diversion
– Channel works/maintenance
– Walls and embankments
– Non-structural measures
Flood management option appraisal
Overview
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Off-line Storage facility
River Tonge
HR Wallingford Ltd 2002
HR Wallingford Ltd 2002
• Model used to determine feasibility of options. Objective is to achieve “sufficient and robust” options
• MDSF used to determine benefits of different options
• Off-line storage facility for the River Tonge:
– Requires modification to achieve stated policy for the Tonge
– Difficult to locate within Bolton (consider upstream sites)
• This is an example only - need to investigate other options
Flood management option appraisal
Conclusion
HR Wallingford Ltd 2002
Overview of the CFMPs and the MDSF
Rob Cheetham
HR Wallingford LTD