1. Indicating the length of time (in time units, or in per cent of total time) for which runoff equals or exceeds any given intensity.
2. Footnote, page 126. Stage, Sven, and Larsson, Yngve:Incremental Cost of Water Power. Power Apparatus and Systems (AIEE), August 1961.
3. Stage, Sven, and Larsson, Yngve:Incremental Cost of Water Power. Power Apparatus and Systems (AIEE), August 1961.