South Westland's rivers don't have time to lazily meander their way to the sea as their counterparts across the Southern Alps in Canterbury do.
Born in those mountains, often only a few kilometres from the coast, they plunge down, deep, wide and fast, full of eddies and undercurrents rushing towards the Tasman Sea.
They are rivers to be treated with caution. Death by drowning was an especially common cause of demise in the 19th century - and among those claimed by the water was my Great Uncle Fred.
Fred had been fording the Big Wanganui River, north of Franz Josef, on horseback but was never seen alive again. Instead, his body was found washed upon the beach at Hokitika with all his possessions intact apart from the money he was carrying to buy cattle for the family farm.
What we'll never know now is did the river claim Fred all on its own or was he assisted into a watery grave and, if so, who relieved him of most of the family's cash?
I think of Fred every time we cross the bridge that now spans the Big Wanganui - a small West Coast tragedy among many - one ordinary man among a cast of many larger-than-life figures.
One such character was Arawata Bill, a legendary bushman and prospector whose exploits were well known to my Coaster ancestors.
William O'Leary's nickname came from the river south of Haast, on the road to Jackson Bay; the absolute end of the road on the West Coast.
The Arawata sweeps out of the steep forested valleys of Mount Aspiring National Park and during the gold fever era of the 19th century it was believed that the Arawata Valley was going to prove a rich source of gold nuggets.
Arawata Bill spent most of his life looking fruitlessly for this treasure. It was hardly surprising that he'd been struck with gold fever as he'd been born in Central Otago in 1865 and experienced the gold rushes there.
He didn't restrict himself to the Arawata either. A few mountain ranges towards the sea was the Cascade River where - the story goes - a French sea captain had once buried a ship captain's bootful of gold.
And then there was the legend of the lost ruby mine...
Arawata Bill, along with his mare Dolly, prospected in the Arawata and surrounding valleys for 40 years.
It must have been a lonely existence but Arawata Bill's obsession never lost its grip on him and his years in the wilderness remain a testament to pioneering grit.
Just a few weeks ago I stood on the Arawata River bridge and looked upstream into Bill's realm of lost dreams.
The Arawata swirled deep, silent and emerald green beneath me, the mountain peaks were sharply incised against a cloudless sky.
There is no road access up the Arawata which is perhaps as it should be but there is a 'No Exit' gravel road that leads up the Jackson River, one of its tributaries. The turn-off beckoned just over the bridge.
A sign warned us that ahead lay 20 or more kilometres of winding road but the lure of the unknown was too strong. If we stayed the course we'd end up in the Cascade Valley - home to the Frenchman's gold-stuffed boot and just a mountain range or so from Milford Sound.
The Jackson River flowed bank to bank, rippling over a bed of granite stones, worn, rolled smooth.
Beech forest fringed the banks, the only sign of life a tomtit flitting among matagouri bushes in a grassy clearing beside the river.
The road eventually parted from the Jackson to wind up a forested ridge, now in deep shadow.
We stopped at the Martyr River where the water was flowing not towards the Jackson but down into the Cascade. The water churned and foamed through a chasm about 10 metres below the bridge.
Beyond this point the forest was replaced by scrublands and to the south were the peaks that just a few days earlier we'd seen from Paradise at the head of Lake Wakatipu. But this felt even more remote.
Regrettably we never made it to the end of the road - a ford littered with rocks we judged would not do our car's exhaust system any good defeated us.
One day I'll go back but in the meantime I can, as Denis Glover wrote in his poem dedicated to Arawata Bill, be filled with "wild surmise" about what might lie ahead in this terrain he loved so well.