Veeder-Root — 1 Executive Summary

7.3.2.3 Roughness ............................................................................................... 77 7.3.3 Numerical precision ....................................................................................... 77 7.3.4 Common Problems with 2D Models ............................................................... 77 7.4 1D-2D models...................................................................................................... 78 7.4.1 Common Problems with 1D- 2D Models ........................................................ 78 7.5 Boundary Types and Locations ...........................................................................

79 7.5.1 Fluvial Models (1D and 2D) ............................................................................ 79 7.5.2 Pluvial Models (2D) ........................................................................................ 79 7.5.3 Coastal Models (2D) ...................................................................................... 79 7.6 Initial Conditions .................................................................................................. 79 8 Calibration, Validation & Sensitivity Analysis ................................................................

81 8.1 Introduction .......................................................................................................... 81 8.2 Calibration ........................................................................................................... 81 8.2.1 Fluvial ............................................................................................................ 83 8.2.2 Coastal .......................................................................................................... 85 8.2.3 Pluvial ............................................................................................................

86 8.3 Common Issues with Calibration ......................................................................... 86 8.4 Sensitivity Analyses ............................................................................................. 87 8.5 Confidence .......................................................................................................... 89 9 Scenarios ..................................................................................................................... 92 9.1 Introduction ..........................................................................................................

92 9.2 Fluvial .................................................................................................................. 93 9.3 Coastal ................................................................................................................ 93 9.4 Pluvial .................................................................................................................. 93 9.5 Integrated Catchment Studies ............................................................................. 94 10 Climate Change ........................................................................................................

95 10.1 Introduction .......................................................................................................... 95 10.2 UKCP09 Projections ............................................................................................ 95 10.3 Fluvial .................................................................................................................. 96 10.4 Pluvial ................................................................................................................ 100 10.5 Coastal ..............................................................................................................

101 10.5.1 Extreme Still Water Level Rise ..................................................................... 101 10.5.2 Waves.......................................................................................................... 102 11 Defences ................................................................................................................ 103 12 Natural Flood Management .................................................................................... 104 12.1 Introduction ........................................................................................................

104 12.2 Modelling Approaches for NFM Studies ............................................................. 104 12.2.1 Short Listing of Measures ............................................................................ 104 12.2.2 Options Appraisal ........................................................................................ 106 12.2.3 Detailed Design ........................................................................................... 106 12.3 Consideration of NFM within Flood Studies ....................................................... 106 12.4 Hydraulic Modelling as part of an NFM Study ....................................................

107 12.5 Hydrological Modelling as part of an NFM Study ............................................... 109 13 Flood Mapping ........................................................................................................ 112 13.1 Introduction ........................................................................................................ 112 13.2 Fluvial ................................................................................................................ 112 13.2.1 1D flood Mapping .........................................................................................

112 13.2.2 2D Flood Mapping ....................................................................................... 113 13.3 Coastal Flood Mapping ...................................................................................... 113 13.3.1 Horizontal Projection Method ....................................................................... 113 13.3.2 2D Coastal Flood Mapping ........................................................................... 113 13.4 Pluvial Mapping .................................................................................................

114 13.5 Post-Processing ................................................................................................ 114 13.6 Quality Checking ............................................................................................... 114 14 Quality Assurance and Quality Control ................................................................... 115 Flood Modelling Guidance for Responsible Authorities v1.1 4