• [ M98 ][ V2 ]    The design menu includes something called a Diversion structure. What is this used for?

You may design a pipe to carry a 5 year flow, but if this subjected to a 100 year storm the pipe will be unable to capture all of the runoff. The diversion command allows you to separate the total runoff hydrograph into the two components that will be conveyed by the minor systems and the major system. The major system is simply the flow that will remain on the surface of the road.

• [ M98 ][ V2 ]    In the Diversion design there is a check box labelled "Computed outflow peak." What is this for?

In the diversion design the excess flow is defined as the difference between the current peak flow and the overflow threshold. This can be split in two ways. You can either define the fraction of the excess flow that will be diverted or, by clicking on the "Computed outflow peak" check box, you can define the required outflow peak and MIDUSS will calculate the corresponding diverted fraction.

• [ M98 ][ V2 ]    When doing a Diversion structure design where does the diverted hydrograph go?

The diverted hydrograph is saved as a file which has the name given by DIVnnnnn.hyd where ‘nnnnn’ is the node number at which the diversion takes place. This file can be recovered at a subsequent stage of your MIDUSS design session in order that you can check the capacity of the major system.