I live in Canterbury New Zealand and year round rely upon water that comes to me from the Waimakariri river.

Waimakiriri is one of the largest rivers in the province and comes down from the Southern Alps to fan out across the Canterbury Plains. The river has over time built the plains up from what was once sea into one of the largest and most productive farming areas in New Zealand.
I decided to explore the river to try and see the source of the river- the White Glacier far up in the Southern Alps.
You can drive up to near the glacier on the state highway and from their trek up the Waimakiriri river towards the glacier.
There are numerous huts in the area mostly ones built and maintained by the government and provided for anyone to use at a small cost.
So starting from where the road ends my target was a hut called Carrington which is a good base from which to explore the upper reaches of the river system, including my ultimate target, the White Glacier.

Started from the southern side of the river which is possible when the river is low, but if the river is up you need to start from the other side as on that side there is a track that avoids the river bed and goes through bush above the river...but that track is harder and slower and further than starting from the north side (Klondike Corner)
So from the north side of the river there is no track- you just follow the riverbed up towards Carrington Hut which is about 14 km.
The first part of the trek is up the very wide riverbed when in dry times the river can be completely submerged under the rocks. There are broad fans of rock scree coming down from tributary streams on either side of the main river.
After about 2-3 hours you you pass the Anti-Crowe hut on your left and just past there the river goes through several turns where you will almost certainly have to cross the river. At times the river is too high to cross and access to Carrington Hut is cut off and so the Anti-Crowe hut provides a fallback.

Got to Carrington hut after about 5-6 hours. It is located in beech forest on a rise near a major compound fork in the river where the Waimakiriri braches into several major tributaries.

If you stay in the hut it costs about NZ$20/night but I decided to save my sats and bring a tent. There is a really large sheltered area near the hut where you can camp and its free.

You can also get an even better view than from the hut.

As evening closed in a helicopter came and landed near the tent- I went out to see what was up and followed the noise and strong kerosene fumes coming from the helicopter to find it a rescue helicopter that had come so try and lift out an injured tramper in the mountains behind Carrington.
Carrington is right on the 'main divide' between the east and the west coats and the huge mountain range mostly blocks the cloud coming from the west and forcing them to rise in altitude creates rain on the western side while the east side mostly remains dry. You could see this divide in the weather very clearly from Carrington where the sun was still out, but in the valleys to the west thick cloud and rain were visible- this is where the helicopter had been searching all day for the injured tramper. They lifted off for one last try before dark and a few hours alter came back successful.
They had only landed at Carrington to drop off the medic and his gear to lighten the helicopter and make it possible to winch down to the tramper.

This was a reminder of the dangers up in these mountains and stayed with me the next day as I walked up the White River branch of the Waimakiriri towards the White Glacier and Barker hut which sits just below the glacier.

I decided to make it a day walk rather than trying to carry a pack and gear to stay in the Barker hut which would have taken up another day and risked being caught by bad weather that was due within the next 48 hours.

The weather stayed good all day and once the sun came up it got quite hot. From Carrington hut you walk up to the left fork on the river and that is the White River branch.
A rainbow and pot of gold at the start of White River?

As you walk up White River it gets steeper and the rock get larger and less settled. You need to take care both from the risk of falling rocks and a rock moving under your feet.

There are large screes and cliffs on either side and this closes in more and more until you reach a pinch point in the valley where you need to climb up on the true left side of the river (right hand side if you are facing up river) where the scree slide is partly grown over with pioneering plants and where there are occasional marker posts indicating which is the best way to follow although you really need to decide that for yourself as the scree slopes are constantly changing.
Every winter snow and ice will cover the sides on the valley, prizing apart more of the rock from its virgin state into large and small boulders that then obey the laws of gravity.

At one point sidling across the scree I looked up to see what looked like a beached whale- it turned out to be a large slab of ice left over from last winter and working its way down the scree I was traversing. It was covered in dust and debris so was not immediately visible as ice.

Once you pass this final pinch in the valley there is still a short section of the river to cover and then a steep climb up to the hut and the glacier above it.
Decided that was far enough as it was now afternoon and still had to return back to the tent and hut, though would like to return sometime to get up to the hut which is in an amazing location perched up on the ridge below the glacier and amongst the highest peaks of the area.