Hydraulic characterization of flood drainage systems (FDS), as outlined in Paper 11320,(1) is the focal point of this paper and is discussed in nine separate case studies, The hydraulic characterization of each case is presented after broadly outlining its general perspective, context, and modelling details, The studies are wide in scope and each one can be inclusive of the following characters (a) attenuation character: a mechanism of slowing down caused by storage and dynamic effects, with storage being more significant than dynamic effects in floodplains or perched main rivers spilling over on to floodplains (b) storage-based systems: a character describing the suppression of dynamic effects and the prevalence of reservoir effects (c) responsive systems: a character describing the dominance of gravity, which may be associated with flood drainage of upper catchments (d) retarding basins: another floodplain feature causing main river flows to be slowed down (e) inertial character: specific to nearly-flat tidal and similar waterways (f) distributive systems: a physical feature concerned with confluence, bifurcation and loops often associated with many encroached FDS or deltaic conditions (g) locally-governed systems: a reflection of the effects of man-made and natural features of flow regimes as in industrial valleys (h) complex hydrodynamic, composite and compound systems.