Towards a 2D x 1000 sq km Catchment Flood Alleviation Model of Adaptive Landuse

The animation shows primary Upper Severn tributaries and indicative 2D modelling of a 40km2 stream within the 1000km2 main river catchment perimeter.  Presented also are the scope and goals of a Mid-Wales project, in association with River Trusts, to quantify the effect of both floodplain and landuse roughness on the depth and flow of extreme events. The map of c. Q80 mid-storm flood-depth is indicative of opportunity for c. Q40 porous (high roughness low impact RURAL) green storage.

40km2 Pilot Settings: 10/100m grid; applied synthetic 75mm x 24 hour rainfall; normal outflow; no infiltration; existing riparian features; baseline homogeneous non-strategic roughness.

Parameters of Opportunity (never forgetting the importance of benign lateral impact):  Agri-roughness, infrastructure crossing adaptation, terrain-hillslope, stream-sinuosity (vector difference), soil moisture/permeability, coarse-fine rainfall-runoff analysis (as above); ; All towards a goal of remotely sensed hotspots sampled, ground-truthed and weighted.

(For full screen, press ‘play’ and left-click the lower RH corner of the animation)

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Acknowledgements