Little bridges span the streams, filling the dams and ultimately gushing from Aucklanders' taps. The Waitakere forest gets half as much rain again as the city and it pays to pick the time of year when you do the trail.
The Hillary Trail connects with other trails into a single 70km walk from the Arataki Visitors' Centre to Muriwai. Around every corner there is a magnificent view - kauri soaring above the grey-green canopy, distant ocean views, even the dams are a thrilling sight. The Slip Track takes us across the Nihotipu tramline to the Pipeline Track and on to the Lower Nihotipu Dam Road.
The walking is easy, although steep dropoffs send my heart into my mouth as my daughter negotiates occasionally muddy paths with the cocky surefootedness of someone who doesn't know the words "spinal injuries". We clamber over fallen trees and around deep puddles and hug kauri trees.
By the time we emerge six hours later at the Karamatura Valley we are looking forward to taking off our boots and enjoying a lie-down.
But the call of icecreams at the Huia Store prove too much and we decide the half-hour diversion is worth the effort. Finally, in the campground with its dramatic volcanic rock backdrop, up went the tent and, after an early dinner of cooked dried food, we turned in.
The next day was a matter of retracing our steps - uphill. The Karamatura Track descends 150m, goes up 250m and down again to sea level.
By day two we felt every uphill step. But it was a privilege to watch my daughter - who is driven to and from school every day - persevere, despite her tiredness.
Introducing her to the beauty and adventure of the New Zealand bush was a priceless experience.
Keep a-walking
Grace Jack, aged 10
My legs ached. I could have done with more sleep but I knew today was going to be just like yesterday. In reverse. The day had begun with us signing in at Arataki Visitors' Centre and then we walked into the bush. There were beautiful waterfalls and the bridges over the streams were fun. There was a giant kauri which I tried to hug but couldn't get my arms around.
I saw the dams where our drinking water comes from. They were like huge lakes. We finally came out of the bush and I got icecream at Huia Store. I think I deserved it. I was so relieved to see our campground. The next morning we had to walk up all the stairs we'd walked down the day before. Mum kept saying it's going to be the next corner and we finally came back to the lookout place.
