Short answer (from cave diving experience): Not much (if the water flow and passage size allows divers to swim thru)
Bit longer (scientific): Assume a 10cm/sec flow, 1 meter diameter tunnel, 10cm wall roughness, 1500 meter length -> http://www.pressure-drop.com/Online-Calculator/ Gives a pressure drop: 7.56 mbar / 0.01 bar br, Robert On 26.06.2013 14:42, Footleg wrote: > I am working on a master survey of the Kingsdale System in Yorkshire, > UK. There is a substantial submerged portion to the system. Over a > rough distance of 1500m of sumped passage, what difference in water > levels could be expected between the upstream and downstream ends of > the sump? > > The diving data just records water depth, so it computes both ends of > the sump as having identical water levels. We know in flood conditions > the upstream sump level backs up considerably. But assuming the diving > is done in conditions of low flow, what typical difference might be > reasonable to expect in the altitude of the resurgence and of the > upstream end of the sump (determined by survey data from an entrance)? > My data shows a significant difference, but I do not know how much of > that difference might be expected and how much is due to errors in the > dry passage survey and entrance altitudes? > > Footleg > _______________________________________________ > Therion mailing list > Therion at speleo.sk > http://mailman.speleo.sk/mailman/listinfo/therion > > >
