Flood Plain Modelling

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Flood Plain Modelling
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Flood Plain Modelling

• Flood Plain Model Options
• 1 - D - Lump River and Flood Plain as Single
  branch (Limitation Same Water Levels in River
  and Flood Plain)
• Quasi 2-D - River and Flood Plain separate
  Flow Paths - Requires accurate and detailed
  Data - Relevant for Flood Mapping, Flood
  Plain Inundation and Drainage Modelling Flood
  Damage assessments

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One dimensional flood flows
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Two dimensional flood flows
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START
N
Flood plain model not needed
Does the river spill?
Y
N
Do the spill areas convey significant flow
discharges ?
Are levees present ?
N
Y
Y
Flood Cell with link channel
Additional Flooded Area
Are spill flows conveyed parallel to the river ?
N
Flood plain attached to cross section
Y
1-D
N
Are levees present ?
Y
Is the flood plain flow frequent interrupted by
roads and other flow obstructions?
Y
N
Q 2-D
Interlinked Flood Cells
Routing Channels
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Flood Plain Modelling
RIVER MODEL 1D
RIVER CROSS-SECTIONS
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Flood Plain Modelling
SCHEMATIZATION (1 DIMENSION)
LOOPED RIVER NETWORK
TRIBUTARIES
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Flood Plain Modelling
SCHEMATIZATION OF FLOODPLAINS (QUASI 2D)
PARALLEL RIVERS
FLOODED AREAS
LINK CHANNELS
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Channel Center-Lines
SCHEMATIZATION (1 DIMENSION)
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Non-Channel Flow Axes
SCHEMATIZATION OF FLOODPLAINS (QUASI 2D)
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Inundation Flow Network
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Integrated Flood Plain
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Flood Plain Schematisation
Flood Plain Description, definitions
FP2 Add. Storage
FP1 Ignored
River
Flood plain
River
Flood plain?
FP3 Part of Cross section
FP4 Separated from River
River
Flood plain
River
Flood plain
Linkchannel
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Flood Plain Schematisation
?
?
FP1 FP2 FP3 FP4


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MIKE 11 Descriptions FP2 and FP3
FP2 Add. Storage area in processed data
Raw data view
Processed data table
FP3 Relative Resistance in raw data
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MIKE 11 Descriptions FP4
River channel and floodplains modelled
separately. Link channels define flow exchange
properties
Channel 1
Channel 2
Channel 3
Link1
Link2
Link Channels (Network Tabular View)
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River-Floodplain Flow Exchange
Floodplain
Connection to
River Branch
U/S Bed Level
D/S Chainage
Link Structure
Manning's Coefficient
River
U/S Chainage
D/S Bed Level
Connection to
Floodplain Cell
or Branch
Longitudinal Parameters of a Link Structure
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Flood Plain Inundation
Flood Plain Inundation, definitions
No FloodingFL1 Local Rainfall FloodingFL2
Flooding via KhalsFL3 Flooding via Levees
No Flooding
FL3
FL2
FL1
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Flood Plain Drainage
Flood Plain Drainage, definitions
Flood Plain Inundation, definitions
DR1 Drainage via ChannelDR2 Drainage via
Levees
Flood Plain
River
Channels
DR1
Flood Plain
River
Levee
DR2
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Storage calculated from cross section width
dx
/2
dx
/2
1
2
b
b
2
1
b
3
A
b
(dx
/2dx
/2)
s
2
1
2
dx
dx
1
2
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User Defined Storage
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Total Surface Storage
Total surface storage Storage width . dx Add.
Storage Area
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Flooded Area