Black Canyon National Park reaches milestone

By Andy Piper   |   August 21, 2009   |   3:01 PM

The Black Canyon of the Gunnison isn’t black. In sunlight, it’s more the color of a chocolate-mango smoothie.

The name comes from the shadows that darken its depths — shadows cast by sheer rock walls that average 2,000 feet high along the 14 miles contained in the national park that bears its name. In places, the walls are only 40 feet apart at the base.

This year, the Black Canyon of the Gunnison National Park turns 10, one of the four most recent parks added to the National Park system. This year also marks the 100th anniversary of the Gunnison River diversion tunnel. Opened in 1909 at the head of the canyon, the tunnel transfers irrigation water nearly six miles to the Uncompahgre River, so unused water flows back into the Gunnison downstream at Delta.

The park is planning events in September and October to commemorate both anniversaries.

The Black Canyon is neither the largest nor the deepest canyon in the U.S., but it has taller sheer vertical cliffs than the deepest canyons (the Grand Canyon and Hell’s Canyon of the Snake River) and a greater depth or average narrowness than other steep-walled canyons (Royal Gorge, Zion and Yosemite). The face of the Painted Wall, 2,250 feet high, is the tallest cliff in Colorado.

It is a dizzying sight to look over the rim and realize that a brightly colored sesame seed moving along the riverside is actually a kayak being portaged past rapids.

Two factors give the Black Canyon its unique geology. First, the walls are formed of hard metamorphic gneiss and schist, which hold their shape and don’t crumble to form shallow slopes and steps like those found at the Grand Canyon. This mass of rock is known as the Gunnison Uplift.

Second, the Gunnison River is an effective cutting tool, falling more than half a mile in the 50 miles below Blue Mesa Lake, and filling with silt from the eroding West Elk mountains and Collegiate Peaks. Before being dammed and diverted by humans, its natural spring runoff flow approached 12,000 cubic feet per second. Today, flows rarely exceed 3,000 — likely a good thing for kayakers, since the park’s advisory signs say that in flows “above 3000 cfs … death is probable.”

The Gunnison had an easy time cutting through surface layers of volcanic ash from the formation of the San Juan mountains, and by the time it hit the hard rock of the uplift, about 2 million years ago, it no longer could overflow its banks to find a new path. With nowhere to go but down, it began grinding out today’s Black Canyon at the rate of an inch per century.

The canyon’s dark beauty is accented by intrusions of pegmatite, an igneous (volcanic) rock that forced its way into cracks in the uplift over the eons. It is most visible in the form of dyke walls that jut into the canyon (making impressive overlooks), and in the pale stripes that decorate the face of the Painted Wall and other cliffs.

Like many 10-year-olds, Black Canyon park doesn’t get a lot of respect. Despite its drama and the fact that it is at the center of a recreational complex along the Gunnison that includes Blue Mesa Reservoir, the Curecanti National Recreation Area and the Gunnison Gorge National Conservation Area, Black Canyon is the least popular of Colorado’s national parks, drawing only about one-twelfth as many visitors as Rocky Mountain National Park. The South Rim campground has not filled up in more than 25 years.

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Visitors to Colorado’s national parks in 2006

• Rocky Mountain N.P. – 2,745,626
• Mesa Verde N. P. – 557,248
• Great Sand Dunes N. P. – 258,660
• Black Canyon of the Gunnison N.P. – 219,576 (2007)

Source: National Park Service

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Getting there

Perhaps one reason the Black Canyon has relatively few visitors is that it’s a little off the beaten path.

Montrose is the closest city to the canyon. The fastest route from Denver is to take Interstate 70 west, then:

• For the North Rim, turn south at Glenwood Springs on Colorado 82; turn south again on Colorado 133, passing through Carbondale and Redstone and over McClure Pass to Hotchkiss; and go south on Colorado 92 past Crawford State Park to find the Black Canyon Road.
• For the South Rim, continue on I-70 to Grand Junction and backtrack southeast on U.S. 50 through Delta and Montrose to Colorado 347.

The scenic — well, other scenic — route is to take U.S. 285 southwest to Salida and pick up U.S. 50 over Monarch Pass and through Gunnison, then:

• For the South Rim, just stay on U.S. 50 to Colorado 347, about 7 miles east of Montrose
• For the North Rim, turn off U.S. 50 onto Colorado 92 at the foot of Blue Mesa Lake near Sapinero, and follow 92 to the Black Canyon Road.

Both rims have campgrounds, rim roads and unique overlooks. The south rim is more developed, with a paved road, road access to the Gunnison river and tunnel portal (a steep drive), and the visitors’ center and park entrance.

Activities include canyon hiking, rock climbing and kayaking.

(Roll your mouse pointer over a full-size photo to see the caption.)

Categories: Region, Video

Tagged: black canyon, canyons, cliffs, gunnison river, gunnison uplift, kayakers, national park, san juan mountains, uncompahgre river