Rain Forest Express

I never knew about this, could be something to check out, although it looks to be aimed at the younger generations. Visual experience of where Auckland's water comes from... 

Its been going since 1998 and receives 12,000 visitors a year. It offers a unique and upclose experience through the Waitakere Ranges. You travel into the Waitakere Catchment area and experience of :

•   Ten pipeline tunnels and nine bridges, including the dramatic Quinn’s Viaduct
•   The historic and tranquil Upper Nihotupu dam - a working water supply dam
•   Personalised commentary on local history, flora and fauna
•   Close-up views of glow-worms and cave wetas
•   Scenic picnic spot with tables and barbecue

View to the Manukau Harbour

The bridge and pipeline

During the journey your train driver will tell the story of the Rain Forest Express from its role in building the dams which now help to sustain Auckland, through to its use today. After visiting the dam, take a stroll to Seaver's Camp, overlooking the Nihotupu Valley and Manukau Harbour. The train will collect you from the Camp for the return journey.

http://www.watercare.co.nz/community/rain-forest-express/Pages/default.aspx