an old river trip

Geomorphology of the Yampa and Upper Green

Friday 2:30 p.m. “We should be there in four hours,” Jack bellows to the dozen or so newly acquainted students huddled around the rented minivans. An hour and a half later, barely out of Brigham City and frozen in twenty miles of construction traffic, the driver in front of us rolls down the window of his sedan and rests his head on the highway median barrier.

7:20 p.m. Trying to distract myself from the sickening bounces of our cream-colored minivan, I peer out the overly tinted window. “We will be safe, respectful and successful.” The Duchesne elementary school’s motto seems strangely applicable to our expedition as we caravan into the volatile and educational Dinosaur National Park for our geomorphology fieldtrip. When we get to Vernal, Jack jovially addresses us. “McDonalds has been knocked down but there’s still a Taco Bell.” Sure enough, only a field of dismembered plumbing appendages and cement blocks litter the field beneath the golden arches sign which is still rotating proudly.

10:30 p.m. Our strange group of “carrot snappers” (Jim’s Idaho nickname for Utahans), “potato heads,” and easterners roll into Echo Canyon. It has been a long four hours. Beyond the fecund jungle of tamarisk, the Green River curls around Steamboat Rock, a 300’ sandstone butte bathed in blue moonlight. We set up camp in the sheltered amphitheater of stone and cottonwood.

Saturday 7:00 a.m. Today is qualitatively different—five river miles on a stream with a discharge double what we expected. “Don’t worry, we hiked up to Warm Springs Rapid over the weekend and it was only chest deep,” the seasonal employee’s reassurance is ominous at best.

9:49 a.m. The Yampa River, undammed, laden with sediment and highly variable in flow merges with the cool, clear Upper Green. Jack teaches that the constant 800 cubic feet per second minimum release from the Flaming Gorge Dam allows boating all summer long, “as much as we love to hate dams.” Incised meanders, layer-cake stratigraphy, and fan-eddy complex are the terms of the morning. The width of the river valley depends on the erodibility of the bed material. Bounded by the cemented silicate of Uinta and Morrison formation sandstone, the narrow canyon we stand in is the longest section of sandstone canyon on a free flowing river in the United States. The flood of record, which occurred in 1984, reached at least where we were standing—fifteen or twenty feet above the current water level. Tamra, the park botanist pulls a woody plant from the sandy soil. “Perennial Pepperweed,” she justifies her action, “an exotic that didn’t exist here before but got established in that flood.” Jack describes how with each flood event, the floodplain is raised by sediment deposition. The flood banks slowly separate themselves from their active channel, making it harder for the stream to interact with its floodplain. Eventually the fossil floodplain becomes a dry terrace. Somehow it seems like a metaphor for failed marriage.

11:43 a.m. Patrick waves his arms at us, describing how the Colorado Pikeminnow spawns on the descending limb of the hydrograph. As the river’s discharge diminishes, the fry are distributed in backwaters and eddy shelters. The fish are more pike than minnow—the largest minnow in the U.S., growing up to six feet long and ranging from the Sea of Cortez to the headwaters of the Green and Yampa. The river system’s fragmentation has endangered the fish which currently only have a few known spawning sites—one of which is next to us on the Yampa.

12:20 p.m. We skirt along the south side of the river until the trail cliffs out against the 1,000’ sheer walls. Most of the class descends to the river. Marshal and I stay high, watching the diminutive Lisa go in almost to her neck. “I bet she never did that at Texas A&M,” Marshall quipped as we shuffled across a precarious ledge. We ford the river after the constriction to join the rest of the group at the undeveloped rafting campsite, Box elder Park. We only get drenched to our bellybuttons.

1:27 p.m. We eat our lunch sitting on the fine-sand of the point bar. Patrick pulls out a camp stove and re-hydrates a gourmet pack of egg plant lasagna. I eat a pop tart and a slice of greasy American cheese. Tamara teaches us that while the riparian zone only makes up 1-2% of the park’s land area, it accounts for 50-90% of its biodiversity. I strip down to my shorts, swim across the river and jump off a 25’ cliff into what I know from class is theoretically the deepest part of the channel (right against the outside bank). Jack cautions me publicly when I get back to the group, “You never know what’s down there hidden by the silt, you gotta be careful.” but pats my shoulder and whispers, “nice jump Ben,” as I walk back to my gear.

3:00 p.m. Our group splits up and Jack asks me to make sure the river right half is doing alright. I lope past Lisa and Heather and tell Loles, a Spanish student visiting from Madrid to follow David and I around a boulder rather than going through the river. “I cann move!” I spin around to see Loles standing thigh-deep in the river. “I cann move!”

“OK then Loles, just walk back to the bank.” David assures her calmly.

“No I cann move.” Dave and I smile at one another, finally understanding her through her accent and step down into the stream to pull her out. She loses a sandal in the silt which David fishes out with his foot.

4:25 p.m. Jon and I sprint around the last meander to the famed Warm Springs Rapid. House sized boulders lie in the channel, half exposed like crocodile teeth slicing through the tissues of the muddy river. I toss my near-empty backpack to David and dive off a rock into the turbid channel—bound for the actual warm springs on the other side of the river. As I slip into the twisting flow I see Jon lower himself in and hear Jack shout “I wouldn’t . . .” from the bank but his warning is drowned by the power of the stream. I side stroke to the opposite bank and jog up to the spring’s source. Seeing the piles of bighorn droppings surrounding the pool like clumps of fibrous grapes, I decide not to quench my readily growing thirst but return to the group.

4:32 p.m. Christy is expounding on the creation of the rapid. In 1965 a giant debris flow completely blocked the river at this point. There were several groups of camper in the area who saw the stones and dirt march into the river—destabilized by a rain event. This area was particularly prone for such mass wasting events since it is the mostly denuded remains of a landslide which occurred 10,000 years ago when the canyon wall collapsed. In 1965, even two days after the debris flow, holes were still shifting in the rapid. The first raft to try the passage flipped and one of its crew drowned. They helicoptered in supplies to the remaining campers. Eventually the nique-point, or area of steepest gradient, migrated downstream naturally steepening itself to be able to transport the sediment. A large field of watermelon sized cobbles forms a bar downstream on the outside bank of the first meander below the constriction. Ten or so channel-widths downstream of that bar on the opposite bank, a bar of baseball sized cobbles pushes out into the channel. Jack names the whole feature a fan-eddy complex and says that frequency of these systems can determine overall stream slope.

6:45 p.m. Thunder rolls through the canyon like a Cadillac Escilade. We quicken our pace, following the river left trail that Marshal and I had discovered. Jack stands calf-deep in the river below shouting combat directions up to us. “Ben you take the lead! Marshal you run sweep, we need to get out of here!” We are still scattered across the cliff as the wind and thunder claps intensified. Dry, dust-bearing, gusts blinded us as we squeezed across the even more perilous ledge to get back to the main trail. The rain hit us as we sprinted back to our tents.

3:00 a.m. Christy wanders over to Patrick’s tent and asks meekly, “Do you think we’re on the active floodplain?” The curve of the Green around Echo Park does seem to swell around us like a coil of a constrictor as the rain resurrects the ephemeral desert tributaries around us. I slip out of my bivy sac, pad by Jon—lying on his back snoring like a mountain lion—and curl up on the uncomfortable floor of our Kia minivan.

Sunday 11:42 a.m. Everyone is tired and Lisa is shivering, despite the fact that she’s wearing three coats, gloves, and two pairs of pants—every article of clothing she has. We dig trenches in a reattachment bar below Steamboat Rock to examine the ripple deposit foresets. Like geomorphological forensic scientists, we draw arrows indicating flow direction when the feature was deposited. We dig down a few inches and brush the layered sand to reveal the ripple crests. “They’re perpendicular to the ripple’s travel direction.” Jack digs around a tamarisk trunk showing how you can use the germination horizon to determine sediment deposit age. “Once a section of stem is covered with sand, the growth rings from that point on get constricted. There’s a whole cottage-industry sprung up around sediment/vegetation dating.” Sarah uncovers an anomalous twist which Jack explains is a marble cake formation—caused by soft sediment deformation not flow conditions.

6:50 p.m. We eat the last of our wheat thins, on the road back to Logan. We’re no longer “newly acquainted.” I write a poem as the sun goes down

I’ve died and have been reborn

at least the quadrant of my flesh where you

were embedded has turned to history.

The pages have crystallized

in that dry wind which rakes

through my splayed fingers

and aches my brain—the mucous tacky,

binding up my tendons and conscience.

Oh what a painful shedding

this departure of our mutual dream.

Kindness is a forgotten river rock

but may we both touch it again

when the waters rise.