Flood Plain Modelling

Flood Plain Model Options Flood Plain Model Options: 1 - D : 1 - D : - Lump River and Flood Plain as Single branch ( Limitation: Same Water Levels in River and Flood Plain) Quasi 2-D: 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

One dimensional flood flows

Two dimensional flood flows

Do the spill areas convey significant flow discharges ? Does the river spill? Flood plain model not needed Are levees present ? Are spill flows conveyed parallel to the river ? Flood Cell with link channel Are levees present ? Additional Flooded Area Flood plain attached to cross section Is the flood plain flow frequent interrupted by roads and other flow obstructions? Interlinked Flood CellsRouting Channels 1-D Q 2-D N Y N N N N Y Y Y Y Y N START

RIVER MODEL 1D RIVER CROSS-SECTIONS Flood Plain Modelling

SCHEMATIZATION (1 DIMENSION) LOOPED RIVER NETWORK TRIBUTARIES Flood Plain Modelling

SCHEMATIZATION OF FLOODPLAINS (QUASI 2D) PARALLEL RIVERS FLOODED AREAS LINK CHANNELS Flood Plain Modelling

Channel Center-Lines SCHEMATIZATION (1 DIMENSION)

Non-Channel Flow Axes SCHEMATIZATION OF FLOODPLAINS (QUASI 2D)

Inundation Flow Network

Integrated Flood Plain

Flood Plain Schematisation Flood Plain Description, definitions: RiverFlood plain RiverFlood plainRiverFlood plain RiverFlood plain ? FP2: Add. Storage FP3: Part of Cross section FP4: Separated from River FP1: Ignored Link channel

Flood Plain Schematisation FP1 : FP2 : FP3 : FP4 : ? ?

MIKE 11 Descriptions: FP2 and FP3 FP2 Add. Storage area in processed data Processed data table FP3 Relative Resistance in raw data Raw data view

Link2 Channel 1Channel 2 Channel 3 Link Channels (Network Tabular View) River channel and floodplains modelled separately. Link channels define flow exchange properties Link1 MIKE 11 Descriptions: FP4

River-Floodplain Flow Exchange U/S Bed Level D/S Bed Level U/S Chainage D/S Chainage Link Structure Connection to River Branch Connection to Floodplain Cell or Branch Longitudinal Parameters of a Link Structure River Floodplain Manning's Coefficient

Flood Plain Inundation Flood Plain Inundation, definitions: No Flooding: FL1 : Local Rainfall Flooding FL2 : Flooding via Khals FL3 : Flooding via Levees River Khal High ground No Flooding FL3FL2FL1

Flood Plain Drainage Flood Plain Drainage, definitions: DR1 : Drainage via Channel DR2 : Drainage via Levees Flood Plain River Levee Flood PlainRiver Channels DR1 DR2 Flood Plain Inundation, definitions:

Storage calculated from cross section width dx /2dx 2 /2 b 1 b 2 b 3 A s =b 2 (dx 1 /2+dx 2 /2)

User Defined Storage

Total Surface Storage Total surface storage =Storage width. dx + Add. Storage Area

Flooded Area