With these changes in mind we have recently been working on a stream classification project on the lower northern slopes of the Bombay Hills. Here there are many small headwater streams running through rolling pastoral and horticultural country that drain north and east under the Southern Motorway. Whereas some of the streams have been heavily impacted by farming activities and many hanging culverts are preventing the upstream migration of fish we were amazed to find a very large number of springs.
Springs were bubbling out of the ground at the head of every watercourse, despite there not being any higher land nearby to supply the water pressure. In places we also found lava outcrops in the streams, which recall the Bombay Hill's volcanic origins. The spring water is moving below the rock and emerging wherever it can find a way out, a reminder that we also need to remember water in aquifers when we consider the management of this vital natural resource.