• [ M98 ][ V2 ]    When I look at the hydrograph menu several of the options are grayed out or not available. Why is this?

MIDUSS in general will make items available only when the prerequisite information has been obtained. For instance the Combine command can not be used until an outflow hydrograph has been created. Similarly the Confluence command is disabled until flow at a junction node has been created.

• [ M98 ][ V2 ]    In the hydrograph menu there is an item labelled "Undo." This is not always available. What is it for?

MIDUSS provides you with the opportunity to reverse an action that has modified one of the hydrographs. The Undo command is available only if some change has occurred in one of the four hydrographs. It allows you to reverse some actions such as adding the runoff from a new catchment to the inflow. If you decide that you made a mistake, clicking on the Hydrograph/Undo command will restore both the runoff and the inflow to their original values. Only one level of ‘Undo’ is available.