Overland Flow Modelling
When examining extreme flooding events, water can often break out of its traditional flow routes. Rivers, brooks and streams can spill out into the surrounding flood plain. This overland flow is usually responsible for most damage to homes, businesses and other properties. It is therefore important to be capable of accurately modelling such an event and estimating the potential flow routes and properties most at risk.
Overland flows are highly complex and often awkward to represent accurately using the traditional 1D model. In such an event, a 2D simulation is more appropriate.
Waterco also use these simulations to assess the impact of new developments on potential downstream flooding. Both PPS25 and TAN15 require new developments to have no unreasonable adverse off-site impacts compared with the existing situation.
Using MIKE 21 (a component of the software package MIKE Flood), extreme flood event hydrographs are routed over a Digital Elevation Model (DEM) of the area using high resolution LiDAR data. We use the results to simulate flow velocities, flood depths and overland flow routes
Waterco also has the capability of incorporating the local drainage system, flood defences and buildings into models using MIKE URBAN. Structures can have a significant effect on the final flood extent predictions and so where possible will be included.
