The river is maintained at an artificially high level and falls a couple of metres when the sluice is lowered to allow access to the fourth and fifth chambers, two small air spaces. Normally, however, these are only accessible by cave diving. Beyond the fifth chamber a roomy submerged route may be followed for a further , passing under three large rifts with air spaces, to surface in the ninth chamber – a roomy chamber over long and the same high. High level passages here lead to a former resurgence, now blocked, some above the current resurgence.