(I apologise to the many experienced cavers here who will be only too familiar with what follows but I thought it may be useful to give a very basic summary of Ken Ashton's flood pulse work, for those who haven't come across these ideas.)
What actually matters to potholers is that a sump can be thought of as a U tube. Pour water in one end and it's displaced from the other end almost immediately. It doesn't really matter how long the sump is (for practical purposes) so, for example, a sudden rise in water level in the west Kingsdale Master Cave (during a summer storm) will result in a sudden increase in flow from Keld Head, even though the intervening sump is over a mile long.
However, the movement of a flood wave along a vadose streamway will be considerably slower. (A useful analogy here is that anyone who has watched the Kingsdale bore, or the Ease Gill bore, will know that these pulses travel down their respective becks at something like walking pace; it's a similar effect underground - but with a roof on.)
These two situations are extremes; the reality is often complicated by pitches, canals, etc - but knowledge of this situation has very practical uses for cavers trying to establish what a cave system is like between a sink and a rising. (By this I mean the last place the water is seen and where it reappears - either or both could be underground of course.) For example:
1. A flood pulse hits a sink and the resurgence flows faster almost immediately = you're unlikely to find much dry passage on the direct flow route - although of course divers may encounter high level passages which are dry).
2. A flood pulse hits a sink and there's a delay of many hours before the resurgence responds = a good likelihood of a long (non submerged) streamway being found in between.
3. An area has three sinks and two risings; damming and releasing each stream separately and watching the risings for flood pulses can determine the underground drainage routes without the use of chemical tracers - and tell you a lot about the nature of the cave systems likely to exist in between.
etc,
Here's an often quoted example of where observations as above were made, leading to predictions about the nature of the underground flow, which were subsequently proved pretty much right by direct exploration. If dye is placed into Fell Beck, sinking into GG, it takes many days to arrive at the resurgence (Clapham Beck Head) in dry weather. However, when there's a summer storm and a flood pulse hurls itself down GG Main Shaft, Clapham Beck Head responds sometimes in less than 30 minutes. Both these observations led to the idea that much of the intervening passage is submerged. Apart from the now vadose sections of streamway in Ingleborough Cave, this has largely proved to be the case.
From memory, Ken Ashton's classic work is in Cave Research Group Newsletters (along with many other fascinating articles of course!).