RAA were commissioned as Sub-Consultants to Royal Haskoning to undertake all the hydraulic modelling work in connection with the Surface Water Management Plans for
Stafford, Lichfield, Tamworth, Cannock and part of South Staffordshire.
The modelling was undertaken using the InfoWorks CS 2D in two stages. The initial stage was simply pluvial modelling with no sewers or culverts included in the model. The flows were generated by applying the rainfall directly onto the 2D simulation mesh for the whole of the catchment areas uphill and including the towns.
The second stage of modelling was more sophisticated and included all the sewers and culverts within the urban areas. The hydrology for this model was refined to take better account of the more rapid runoff from the impermeable surfaces within the developed urban areas.
Model outputs were presented as a series of maps showing flood depths and also the hazard ratings; this enables the plans to be used immediately for spatial planning purposes.