The System CA results for a catch basin are lower than the CA results for the upstream catchment
This is related to the bypass flow at the catch basin. If you have a catch basin with a gutter and the captured flow is less than full or 100% capture, some of the flow will be diverted into the gutter. If you look at the results for the catch basin, you will see sections related to bypass flow and intercepted flow, as shown in the screenshot below.
There are results for Bypassed CA and Intercepted CA. Depending on where you are in the system, this will have an impact of the System CA results in the catch basin.
Why is the system time at one of my nodes much larger than the upstream node's Tc or system time?