Hydraulic computer modelling involves the use of computer software to solve advanced mathematical equations, based on a variety of parameters, to provide an estimate on water levels, flows and velocities along a river system.

AWN Consulting uses DHI MIKE 11 1 dimensional (1D) and MIKE 21 2 dimensional (2D) computer modelling software. 1D models simulate the flow of water in one dimension only; along the direction of the river flow. 2D models simulate the flow of water in two dimensions: both along and across the floodplains. DHI MIKE FLOOD software is used as a dynamic coupling programme for both MIKE 11 and MIKE 21.

During any flood modelling exercise baseline information on the dimensions of the river channel and floodplain is gathered as part of the topographical surveys. A hydrological assessment is then carried out to assess the flows in the river channel. The physical make-up of the river channel and floodplains is determined from site visits and photos. Following this the information is input into the flood modelling software.

Outputs from the MIKE models provide data on water levels, flows, depths and velocities for a range of annual exceedance probability (AEP) events.