Noel and her family were following in the footsteps of the great explorer Alexander Mackenzie, gliding their way down 2,000 kilometres of the waterway that bears his name.

Paddling a pair of two-person kayaks northward, the foursome was just past Camsell Bend, about five kilometres below the mouth of the Nahanni River when, as Noel puts it, "something came out of the river to get us."

Noel's husband, Serge, noticed a patch of what appeared to be white water ahead. Because the spot didn't appear on any maps, he decided to take a look and peered ahead through his binoculars.

What he saw was as odd as it was frightening: a six-foot-high wall of water that soon grew to encompass more than half of the river's width. The water was fast approaching their kayaks -- heading upriver.

Screaming "Paddle hard! Paddle to the left!" Serge aimed for the western shore. His bow had barely touched shore when the wave passed by, rocking the kayak in its wake.

"It scared the bejeezus out of the four of us," said Elizabeth.

So it's not a surprise what word Elizabeth uses to describe the river after stroking 45 days on its expansive waters.

"I think of 'power' -- it's a very powerful river. It's not something you want to mess with," she says.

But plenty of people are messing with the river and the six major feeder rivers that are its lifeblood. From hydro-electric dams to sawmills and oil extraction, the Mackenzie River system is a nearly pristine system, but also a river at work.

Compare it, for instance, with the St. Lawrence River. Both rivers have similar discharges. The Mackenzie gushes water into the Beaufort Sea at an average rate of 9,000 cubic metres a second; the St. Lawrence is nearly the same.

But most similarities end at discharge rates. The St. Lawrence is a critically important shipping lane. Millions of people live along its shores.

In contrast, the number of people who live along the Mackenzie barely reaches five figures. In fact, the entire Mackenzie River basin -- an enormous puzzle piece that makes up a full sixth of the Canadian land mass -- is home to less than half a million people and a healthy variety of animal life. Six tributaries -- mighty rivers in their own right -- make up the basin: the Liard, Athabasca, South Nahanni, Peace, Peel and Great Bear.

It's a lot of land offering a lot of resource development with a lot of potential costs.

As an example, the NWT government estimates that the Mackenzie could be tapped for 10,000 megawatts of hydro-electric power, and that's not including the massive potential of its feeder rivers.

But while the NWT government may have its eyes on developing the Mackenzie, the basin in all its romantic vastness is a multi-governmental legislative nightmare.

The waters that exit into the Beaufort Sea flow from five provinces and territories. Although 45 per cent of the basin lies within NWT borders, a full quarter is in Alberta -- raising countless jurisdictional questions.

The Mackenzie River Basin board, created in 1997, seeks to define the answers.

The product of a master agreement signed by the governments of Alberta, British Columbia, Saskatchewan, Yukon and the Northwest Territories, one of the board's major projects is a state of the environment report, to be released sometime this year.

One hundred authors from all points of the basin are collaborating on the report to compile statistics and rankings for numerous facets of the basin's environmental health.

Questions to tackle include: what sort of economic potential does the Mackenzie have? What are environmental indicators telling us today? And what are governments doing to control the use of these precious waters?

Oily trouble ahead The oil and gas industry estimates that 70-80 per cent of Canada's petroleum resources lie within the Mackenzie basin's bounds.

Go to Fort McMurray, Alta., to see a boomtown of 40,000 at ground zero of a massive exploration investment, as huge companies shovel out millions of tons of bitumen and oil from the black sand.

Oilsands operations require massive amounts of water to operate. Steam is used to bring the oilsand to the surface, and water is used to extract the oil.

All those operations pull water from -- and eventually pour used water back into -- the Athabasca River, a large tributary of the Mackenzie River.

B.C. juggles Mackenzie

Alberta isn't alone in being a major manipulator of Mackenzie basin water.

Two huge hydro-electric dams in British Columbia have dramatically affected the way water flows down the Peace River, another of the Mackenzie's tributaries.

The biggest dam -- the W.A.C. Bennett produces 30 per cent of British Columbia's power (2,730 mega-watts). The second is Peace Canyon, a 694-megawatt hydro-electric station. The Bennett Dam is 160 kilometres up the Peace River from the B.C.-Alberta border.

With a spillway that releases about 14,000 cubic metres of water a second, W.A.C. Bennett controls enough of the Mackenzie water basin that engineers at the dam can raise or lower water levels on the Mackenzie River by a third of a metre.

Water today, gone tomorrow Then there are the thirsty parts of the basin-use puzzle. Southern Alberta could run out of water in the next 25-50 years -- or so said some people at consultations held by the Alberta government this summer to discuss a new water strategy. One of the solutions is what's called an inter-basin transfer.

In other words, take a river that naturally channels its water toward the Beaufort Sea and reroute it so the water flows south. The idea was quickly dispelled because the costs were enormous -- as much as a third of a trillion dollars.

What's important is that the idea has been proposed. It could resurface in the future, especially if Alberta's water woes continue.

A hard-working river

Then there are the impacts from human and wildlife transportation -- on the basin's rivers, in them and alongside them.

The river and its tributaries are criss-crossed by popular recreation areas, including Wood Buffalo National Park and Nahanni Territorial Park.

Highways for vehicles of all sorts have effects on what seeps into the river waters. One way or another it all accumulates into the Mackenzie River and down it to the Beaufort Sea. But despite all that, the Mackenzie River system continues to be pure at heart, largely untapped of its resource potential.

"It's probably one of the most intact major river eco-systems in the world," said Jack VanCamp, director of the Mackenzie River basin board. Untapped, but not lazy.

"My image of it is that it's a working river," VanCamp says. "It's not working as hard as some rivers and it's not as badly impacted by development (like the) Danube or the Mississippi, but it's doing it's job."

Monster-sized fish

One job it does well is produce monster-sized fish.

"If you listen to the people out there, and you probably should, the fish populations are stronger now than they were 30-40 years ago," said Sam Stephenson, an Inuvik-based environmental science biologist with the department of fisheries and oceans. "If we hear anything from some people it might be that there's way more pike than there was before. For the fish stocks itself it's probably a good thing, but if you listen to the fishermen it's a bad thing because they're getting too many in their nets (to handle safely)."

How plentiful are the fish? Stephenson has heard his share of stories about six-foot long inconnu actually hauling fishermen out of their boats. For example, he said a few years back a person in Fort McPherson was trying to pull in his net at the Peel River crossing.

"There was this enormous inconnu," said Stephenson. "As the guy tried pulling it into the canoe, the fish actually flipped the guy out of the canoe. The people who were watching and laughing had to rescue this fellow. And the fish got away."