Increasing the maximum size of JFlow simulations 

JFlow has recently been developed to make use of multiple graphics cards, allowing a single simulation to be executed on more than one device. This can help to either speed up model runs, or substantially increase the maximum grid size. 

This functionality, combined with another new feature called 'Indexed Grids', allows JFlow to model large catchments (or even small countries) in a single simulation at high resolution.  For example, the Severn or Thames catchments could be modelled on a 10m grid.  Ultimately, however, any limits on the scale of JFlow models are now entirely due to the hardware available.

These new features are enabling clients to do more with JFlow and to streamline existing models. For example: 

• JBA Risk Management are using these features to produce a global rainfall inundation map. As whole catchments can be modelled in one go, the time required for setting up the model and post-processing the results has been substantially reduced.  In addition, the 'Indexed Grids' code has substantially reduced runtimes.

• The multi-GPU code has been used by JBA Consulting for simulating flooding within the Sacramento Valley in California. It has enabled rapid assessments of complex catchment management options that incorporate levee realignments, additional bypass channels and changes to weir operations.