About MDSF
DEFRA and The Environment Agency are embarking on a major exercise to
develop Catchment Flood Management Plans (CFMPs) for all river catchments
in England and Wales and Shoreline Management Plans (SMPs) for coastal areas.
MDSF (the Modelling and Decision Support Framework) has been developed to support the
implementation of these projects. The purpose of the MDSF is to automate and standardise
parts of the process and make these types of study easier and quicker to prepare.
The MDSF consists of:
- Procedures
- Software and user guide
Procedures
The procedures relate primarily to CFMPs and provide guidance on using MDSF
including:
- Advice on catchment hydrological and hydraulic modelling
- Advice on future land use and climate scenarios
- Advice of flood management policy evaluation
- Procedure for estimating uncertainty in results
Software
The MDSF software consists of
- Relational database
- Customised GIS
- Modelling tools
- User guide
The software provides the following functionality.
- Facilities to manage and view geographical and tabular data
- Import of flood level data from external sources (models)
- Rapid calculation of flood extent and depth maps
- Calculation of economic damages
- Calculation of social impacts of flooding
- Comparison of results from a variety of cases to assist the user in policy
evaluation
- A procedure for estimating uncertainty in the results
Base data
 Base data is referenced into a relational database and then automatically
added to an ArcView project for visualisation.
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External Modelling Results
 External model results are supported through a
simple ASCII format transfer file. This allows MDSF to easily support many different
modelling methodologies. Note that MDSF does not perform any modelling itself but it is
able to intepret the results of external models.
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Flood Extents and Depths
 The flood extent and depth tool takes water
surface levels from the external models and applies them to cross the topography grid.
A TIN is generated representing the water surface. This TIN is then converted to a depth grid
and assessed for defended areas. Although a SAR ground grid is the default, any grid based
digital elevation model (DEM) can also be used.
If an alternative approach to depth calculations is required, this can be undertaken
externally. MDSF then supports the import of depth grids or flood extent polygons for
use in economic and social impact assessment.
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Economic Calculations
 Economic calculations are undertaken using a database
of individual property locations and types (which can be taken from the National
Property Database). Damages can be assessed for a full set or selection
of return periods. In addition, an Annual Average Damage value can be calculated.
In addition, Agricultural damages can also be assessed by calculating the damage
to each square of an agricultural land use grid.
Damages can be aggregated up to any set of polygons. Typically these are Enumeration
districts, river reaches or user defined 'impact zones'.
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Social Impact Assessment
 Social impacts can be assessed in terms of
estimates of the number of people flooded, the percentage of specified areas flooded,
and the relative vulnerability of people living in those areas.
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Erosion Losses
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For coastal projects, MDSF is able to estimate the value of lost agricultural land
and properties lost to coastal erosion. In addition MDSF can calculate an extended life
factor (ELF) to evaluate the benefits of potential coastal defences. MDSF does not
perform erosion modelling but calculates losses based on externally generated erosion
contours.
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Case Evaluation
 A case is a unique combination of a land-use,
climate and flood management (CFMP) or policy (SMP) scenarios. Typically, case
comparison will be against a reference 'base' case representing the best estimate
of the current situation. Sometimes the base case is taken as a 'defences removed'
case.
Absolute and relative tabular comparisons are easily produced. Results can be
easily exported to Microsoft Excel or other packages using the Windows clipboard.
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Uncertainty Estimation
 MDSF provides tools for assessing the uncertainty
in the results.
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Should you require any further information regarding MDSF, please email
.
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