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Canyon Country; Green River - Lodore, Whirpool, and Split Mountain Canyons
Lodore, Whirpool, and Split Mountain Canyons

Green River

Lodore, Whirpool, and Split Mountain Canyons
Since William Ashley's first descent in 1825, the Green River through today's Dinosaur National Monument has become known as one of the West's great river trips. True, the whitewater on the Green has been partially tamed by Flaming Gorge Dam. But the scenery is every bit as breathtaking as when Ashley and Powell explored here (see sidebar).

The three canyons featured in this chapter present a constantly changing panorama, from precipitous walls of red sandstone in Lodore to dramatically folded layers of grey limestone and pale sandstone in Split Mountain. Side canyons hold more intimate wonders: the cool rock sanctuary of Winnies Grotto, the delicate cascades of Rippling Brook, the lush verdure of Jones Hole, and much more. The open flats of Browns Park, Island Park, and Rainbow Park offer stunning views of some of the most dramatic and abrupt canyon entrances in the West.

The Green's flow within Dinosaur National Monument is controlled by Flaming Gorge Dam some 46 miles upstream from the Lodore put-in. River runners negotiating Disaster Falls and Hells Half Mile at low summer flows may wonder why these seemingly moderate rapids inspired such fear in early explorers. However, those who have seen the river during its rare modern periods of high water have a better appreciation for the hazards faced by boaters before Flaming Gorge Dam was built. In 1983 a record snowpack pushed flows above 10,000 cfs. In 1984 a brief flood forced a commercial trip to do the unthinkable: portage Hells Half Mile.

Below Lodore boaters sometimes get a feel for what the untamed Green was like. At peak runoff the Yampa can add 10,000 to 15,000 cfs at Echo Park, transforming normally mild Whirlpool Canyon into a cauldron of swirling, turbulent currents, and turning Split Mountain's easy Class III rapids into a wild joyride down big, chocolate-brown waves. In an average year the Yampa actually carries more water than the Green at their confluence; however, the undammed Yampa yields most of its water in one relatively brief pulse of snowmelt, so at most times boaters find more water in the Green.

The popularity of the Lodore stretch of the Green has brought about a permit frenzy for high-use season trips. Commercial and private groups each get half the launch dates, and the daily number of put-ins is restricted to avoid crowding. It's not easy, but private boaters who persist can usually land a permit, either in the initial draw or by calling in for unused or cancelled dates.

Fifteen million years ago there was no Canyon of Lodore. From the broad flats of Browns Park along what is now the Utah-Colorado border, the ancestral Green River flowed east to join the North Platte and Missouri Rivers. The uplift of the Rockies along the Continental Divide forced the Green to change its course to the south. Then the Uinta Mountains began to rise in the river's new path. This time the river held firm, carving steadily downward as the mountain range grew around it.

One result of this process is the Canyon of Lodore, a narrow cleft incised deep into colorful sedimentary rocks. A brief opening at Echo Park separates Lodore from the next chasm, Whirlpool Canyon. Below Whirlpool the broad flats of Island Park and Rainbow Park divide the upper canyons from their smaller cousin, Split Mountain Canyon. At Split Mountain the Green slices directly through an isolated bulge in the earth's crust, taking a seemingly illogical course through, rather than around, a 7,600' peak. Here, as at Lodore, the ancient Green predates the younger mountain in a classic example of what geologists call antecedence.

On August 17, 1909 the southern slope of Split Mountain was the stage for one of the greatest scientific discoveries of all time, when paleontologist Earl Douglass found eight tail bones from the dinosaur Brontosaurus exposed in a bed of Morrison Sandstone. Further excavations over the next 14 years unearthed some 350 tons of fossils. Scientists concluded that 140 million years ago this incredibly rich site had been a riverside sandbar where dead dinosaurs drifted to shore, decayed, and were buried by sediments. In 1915 President Woodrow Wilson designated the quarry a national monument, and in 1938 President Franklin Roosevelt expanded the preserve to include the canyons of the Green and Yampa. The Dinosaur Quarry Visitor Center makes a fascinating side excursion for river runners.

Despite the fact that they run through a National Monument, the Green and Yampa Rivers were nearly destroyed in the 1950's. As part of the Colorado River Storage Project, the Bureau of Reclamation proposed a dam just below the Green-Yampa confluence in Echo Park. It would have flooded the Yampa all the way to Deerlodge (46 miles) and the Green all the way to Flaming Gorge Dam (67 miles). The fledgling conservation movement fought Echo Park Dam as a dangerous precedent of a major water project encroaching on a National Park. In a compromise still debated today, Glen Canyon of the Colorado River was essentially traded for the Green River in Dinosaur: the former was flooded and the latter was saved.

Difficulty: III; some IV at rare high water.
Length: 44 miles. Shorter runs possible.
Gradient: 13 ft./mi.
Drainage Area and Average Annual Discharge: 19,350 sq. mi. and 1,581,000 af at Flaming Gorge above put-in. 29,660 sq. mi. and 3,298,000 af at Jensen below take-out.
Put-in: Lodore Boat Ramp (5,335').
Take-out: Split Mountain Boat Ramp (4,780').
Peak Recorded Flow: 19,600 cfs at Flaming Gorge; 40,000 cfs (May 18, 1984) at Jensen.

Season: April - Oct. Year-round boatable flows. Controlled by Flaming Gorge Dam, but the undammed Yampa adds considerable flow at mile 19 during spring snowmelt. Spring dam releases range up to 4,700 cfs (and occasionally higher), then taper off beginning in mid-June. Typical releases from July through October of 800 - 2,000 cfs.
Recommended Levels: 800 - 6,000 cfs.
Flow Information: NWS tape, (801) 539-1311, gives the release from Flaming Gorge Dam (put-in), the Yampa flow at its mouth (added to the Green at mile 19), and the Green flow at Jensen (take-out).
Special Hazards: Peak runoff on the Yampa can create big waves on the lower part of this run.
Permits: Required year-round. Much sought after and difficult to get. Group limit 25. For high-use season (second Monday in May to second Friday in September), apply Dec. 1 - Jan. 31 for lottery held in February. Odds are worst for launch dates in May and June, much better in late summer or off-season. No waiting list; call after March 1 for unused dates or cancellations, which account for about a third of the starts. For low-use season, call for dates on a first-come, first-served basis beginning March 1. Apply separately for one-day, 8-mile runs through Split Mountain Gorge.
Managing Agency: River Office, Dinosaur National Monument, P.O. Box 210, Dinosaur, CO 81610; (303) 374-2468.
Commercial Raft Trips: Yes. For a list contact the managing agency.
Land Ownership: Public; mostly National Park.
Scenery: Excellent, varied. Three distinct high-desert sandstone canyons.
Solitude: Very good in high-use season; excellent at other times.
Wilderness: Yes.
Fishing: Fair for catfish and trout.
Wildlife: Bighorn sheep, reintroduced in the 1950's, are commonly seen. Also deer, beaver, raptors.
Weather: Early season (through May) can be cold and rainy; occasional snow. Summers are warm to hot; occasional thundershowers.
Water: Flaming Gorge Dam releases cold, desilted water that should be considered undrinkable. The Yampa adds a heavy load of sediment in spring and early summer. Purify water from side streams and/or pack water and refill at Echo Park (mile 19).
Camping: Excellent, but allowed only at established campsites (which are assigned during high-use season). Only one overnight stop allowed between Echo Park and the Split Mountain take-out.
Side Hikes: Of special note are Pot Creek, Rippling Brook, Echo Park and especially Jones Hole.
Side Excursions: Superb fossil exhibits at Dinosaur Quarry near the take-out. Several scenic viewpoints along Harper's Corner Road and Trail, including a panoramic overlook more than 2,000' above Echo Park and Whirlpool Canyon. (Follow Harper's Corner Road from Dinosaur National Monument Headquarters on U.S. 40). Outlaw Trail and Diamond Mountain Route (see Logistics).

Guides and References:

  • Evans and Belknap, Dinosaur River Guide.
  • Gernant, Hinton, & Hughes, The Canyons of Dinosaur.
  • Wheat, Floater's Guide to Colorado.
  • Riverguide Bandana to the Green and Yampa (Rivers & Mountains). Cloth map.
  • Hayes & Simmons, River Runners' Guide to Dinosaur National Monument and Vicinity. Detailed geologic river log.
  • Hagood, Dinosaur: The Story Behind the Scenery. Geology, fossils.
  • Webb, If We Had A Boat. History and exploration of Upper Green.
  • Zwinger, Run, River, Run. Personal essays, natural history.
  • Stegner, This Is Dinosaur. Geology, human and natural history.
  • Collins & Nash, The Big Drops. Essays on Hell's Half Mile and other famous Western rapids, emphasizing early boating history.
  • Rennicke, Rivers of Colorado and River Days. Essays on this and other Colorado rivers.
  • Maps:

    • USGS 7.5': Canyon of Lodore North, Canyon of Lodore South, Jones Hole, Island Park, Split Mtn, Dinosaur Quarry.
    • USGS: Dinosaur National Monument sheet, the best overall map, covers the entire run plus Yampa Canyon at 1:62,500.
    • Auto Shuttle: About 135 miles (3 - 4 hours) one way. For shuttle services contact River Runner's Transport, P.O. Box 1361, Vernal UT 84078; (801) 781-1180.
      Logistics: Lodore Campground and Boat Ramp is about 10 miles up the "Gates of Lodore" dirt road. Please see Western Whitewater, page 223, for details.

      Excerpted from Western Whitewater from the Rockies to the Pacific
      Copyright 1994 Jim Cassady, Bill Cross, and Fryar Calhoun. Reproduced in cooperation with Fryar Calhoun.


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