To delete any object (node, link, river point), simply right click on it and select Delete. You will be prompted for confirmation before the object is deleted (except for river points). Transmission and return flow links to the deleted object will also be deleted. If you delete a river, all its river nodes will also be deleted.  Objects cannot be deleted if the schematic is Locked.

Deleting Multiple Elements at Once

For convenience, there is a way to delete several objects at a time. To select multiple objects, hold down the Alt key as you click and drag on the main schematic to draw a rectangular grouping box around the intended objects. (To create a non-rectangular shape, hold down both the Control and Alt keys when you click.  Thereafter, each click will create a new point of the shape.  Double click to finish it.)  When you release the mouse button, a red box will appear. Right click inside this red box and choose Delete All Objects in Selected Group from the popup menu to delete them all.  To delete a river, the entire river line must be inside the red box.  Note: If the red box encompasses any nodes that are temporarily hidden, they will NOT be deleted.  Hit the Escape key to cancel without deleting.