Equinox Wilderness Expeditions offers this paddling trip as the naturalist's quintessential arctic canoe adventure. The Nigu and Etivluk, swift and clear, begin in the high country just north of the Arctic Divide, in the heart of the Western Brooks Range. The Nigu and Etivluk rivers flow across treeless tundra for their entire journey. The Nigu River meanders northwesterly through a deep, narrow valley, surrounded by mountains, then opens up, joining the Etivluk, where the rivers turn north, eventually reaching the Colville River. In the hills and valleys in the upper Nigu we find great hiking, as well as archeological sites from the Arctic Small Tool Tradition 1,200 years ago. We hike on dinosaur-backed ridges in the path of early indigenous hunters.

Small and intimate, the Nigu and Etivuk offer canoeing at a relaxed pace through seldom-visited valleys, where wolves, bears and caribou roam, all five species of loons have been spotted, and peregrine falcons find refuge. We enter the Colville Special Area, known for its high concentrations of peregrine falcons and rough-legged hawks. The Colville is part of the National Petroleum Reserve, the largest single block of undeveloped land left in the United States. This vast arctic ecosystem, comprising 22.5 million acres of wetlands, wild rivers, rolling hills and coastal plain, is one of America's most spectacular bird, wildlife and wilderness sanctuaries. We're pushing for National Wild and Scenic designation for the river.

We've timed our trip to take advantage of autumn's colors, the southward migration of the half-million-strong Western Arctic caribou herd, and ripe berries on the tundra (blueberries and cranberries). The Nigu and Etivluk rivers are off the beaten path by Alaska standards, and offer pristine wilderness paddling. We enter the Colville River and explore a section of its distinctive canyon country, pausing to search for fossils and ancient coal beds. With luck, we may see thousands of caribou.

Here's one of our 2005 participant's report on the river:

One of the curiosities of the North Slope is that even though it receives only between five and eight inches of rain a year (similar to some deserts in the Southwest), the underlying permafrost can't be penetrated by water and the surface remains constantly saturated. When I visited the North Slope in June with William Weber, director of the North American Program for the Wildlife Conservation Society, and Steve Zack, an ornithologist and director of the conservation society's Northwest office, the ice had just broken up, and Zack continually (and only half jokingly) referred to the pervasive marshes, bogs, and thaw ponds as "Pleistocene water." We were at the headwaters of the Nigu River, in a valley on the north-facing slopes of the Brooks Range that an outfitter later told us was the most remote part of all Alaska. In the twenty-four-hour sunlight, the snow pack around us was melting off the mountainsides, and water was pouring from the tundra. The caribou herds were returning from their forest wintering grounds closely trailed by predatory wolves and grizzlies. The earth around us was aflame with stands of fireweed, wild lupines, and miniature rhododendrons.

The Nigu flows eventually into the Colville, the North Slope's largest river and one that flows in turn through what is known as the National Petroleum Reserve–Alaska. At twenty-three and a half million acres, the NPR-A (as it's known) is the largest tract of undisturbed public land in the United States and, despite its unprepossessing name, it was the NPR-A we had come to visit.
-PETER CANBY NEW YORK REVIEW OF BOOKS