Note: Each of the RDII UH's has a base time for the convolution of the RDII from each UH. The Time Base is T + T*K from the Time(T) and Storage (K) values used in the RTK data. In this particular case:
· The Fast UH has a time base of 22 hours,
· The Medium UH has a time base of 430 hours, and
· The Slow UH has a time base of 4212 hours.
If this is altered as in the bottom image you can see the difference in the total RDII I&I Flow
· The Fast UH has a time base of 22 hours,
· The Medium UH has a time base of 36 hours, and
· The Slow UH has a time base of 52 hours.
via Blogger http://www.swmm5.net/2013/07/the-time-base-is-t-tk-from-timet-and.html