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40.89693898053995°N 109.18542840751803°W
Green River — CO, UT

Swallow Canyon

12 miles Class I–II 1 days
Flow Monitor Greendale gauge (USGS 09234500) for dam-release flow — 800–2,500 cfs is...
Season Open most of the year; summer is most popular; cold water year-round demands...
Duration 1–2 days (typical 1)
Permit No permit required — day-use fee may apply at Little Hole; no overnight launch...
Shuttle 20 mi — 0.6 hrs
Logistics Easy paved access at Little Hole put-in; Indian Crossing take-out requires a...
Overview

Swallow Canyon is a cold, clear, and accessible 8-mile float below Flaming Gorge Dam — regulated flows, easy riffles, osprey nests, and cottonwood-lined canyon walls make it one of the most approachable river segments on the upper Green.

Swallow Canyon is a short, scenic float on the Green River just downstream of Flaming Gorge Dam, straddling the Colorado-Utah border in the Browns Park region where cold, clear dam-release water winds through a narrow canyon lined with cottonwoods and canyon walls. The flow is regulated by dam operations rather than seasonal snowmelt, making it one of the most consistent and accessible river segments on the upper Green — no significant whitewater, just mellow riffles, osprey nesting cliffs, and a canyon atmosphere that rewards casual paddlers and wildlife watchers alike.

Trip styles
day trip, overnight
Ideal for
families, beginning paddlers, wildlife watchers, fly fishers, day-trippers from Flaming Gorge
River type
canyon river, dam-regulated tailwater
12 miles
1 days typical
Flows & Hydrology

Flow is controlled by Flaming Gorge Dam operations and tracked at the Greendale gauge — more predictable than snowmelt-driven sections but still cold year-round from the dam release.

Reference Gauges

Green River near Greendale, UT

Historical Green River gauge above Flaming Gorge reservoir area. Primary reference for Lodore Canyon and Gates of Lodore trip planning when used in context with current downstream releases.

Current flow — Green River near Greendale, UT

Updating… Provisional

The Greendale gauge (USGS 09234500) is located just below Flaming Gorge Dam, upstream of Little Hole, and reflects dam-regulated flow that directly determines conditions in Swallow Canyon.

7-Day Forecast

Loading forecast…
Seasonality
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Dam-regulated flow from Flaming Gorge is relatively consistent year-round; natural seasonal peaks are reduced.

Spring
cold dam-release water, unpredictable dam flow changes
Summer
afternoon thunderstorms, competition for camping at Indian Crossing
Fall
cold water, rough Indian Crossing road if wet
Geology

Swallow Canyon cuts through the Browns Park Formation — a mix of volcanic ash, sandstone, and conglomerate deposited in an ancient lake basin. The canyon walls are lower and more colorful than the deep gorges of Lodore and Whirlpool, with exposed limestone and conglomerate bands creating a varied visual texture.

Rock Record
Browns Park Formation
Uinta Mountain Group
Province
Middle Rocky Mountains
Rock types
sandstone · limestone · conglomerate
Ecology
History
Logistics

No permit required and easy Little Hole access make Swallow Canyon one of the least logistically demanding floats on the Green River; the main variable is the dirt road condition at Indian Crossing take-out.

Gear
Camp Kitchen

On a seven-day trip, you'll cook roughly 20 meals on a folding table in the sand. The constraint isn't ambition — it's ice management. Days one through three, you have real cooler capacity. Days four and five are the transition zone. Days six and seven are pantry cooking.

The best river cooks plan backward from the last night. If your final dinner is still good — not just edible, but genuinely good — the trip ends on a high.

Dinner Ideas by Trip Day
12River miles
Reading the River

Books that shape the science, history, and stories behind this place.

Canyon Country

Canyon Country

Donald L. Baars · 1989

An accessible introduction to the rock layers, canyon formation, and landscapes of the Colorado Plateau and canyon country.

knowledge
Down the Great Unknown

Down the Great Unknown

Edward Dolnick · 2002

The dramatic story of John Wesley Powell's first expedition through the Grand Canyon and the birth of river exploration in the American West.

storytelling cultural context knowledge
Fluvial Processes in Geomorphology

Fluvial Processes in Geomorphology

Luna B. Leopold, M. Gordon Wolman, John P. Miller · 1964

A foundational scientific text on river geomorphology, covering sediment transport, channel form, fluvial dynamics, and the physical processes that shape river systems.

knowledge
Geology of Utah's Rivers

Geology of Utah's Rivers

William T. Parry · 2016

A geological exploration of Utah’s major river systems explaining how tectonics, sedimentation, and erosion shaped the canyon landscapes of the Colorado Plateau and surrounding regions.

knowledge
How to Read Water

How to Read Water

Tristan Gooley · 2016

A guide to understanding the subtle clues in water movement—from puddles and rivers to oceans—teaching readers how currents, waves, surface textures, and patterns reveal information about wind, depth, obstacles, and landscape.

knowledge tone
Introduction to Physical Hydrology

Introduction to Physical Hydrology

Martin R. Hendriks · 2010

A rigorous, university-level introduction to physical hydrology covering the full water cycle — precipitation, evapotranspiration, infiltration, groundwater, runoff generation, and streamflow — with quantitative methods throughout. The scientific foundation for understanding how rivers work at the watershed scale, from snowpack in the Rockies to baseflow in canyon rivers.

knowledge
River Mechanics

River Mechanics

Pierre Y. Julien · 2002

A rigorous graduate-level treatment of river hydraulics and sediment transport, covering flow resistance, bedforms, channel stability, and the physical mechanics that govern river behavior.

knowledge
River Runners' Guide to Utah and Adjacent Areas

River Runners' Guide to Utah and Adjacent Areas

Gary C. Nichols · 2009

A comprehensive guidebook to whitewater rivers in Utah and neighboring regions, covering river access, rapids, flow considerations, trip logistics, and historical context for river runners.

knowledge
The Colorado Plateau

The Colorado Plateau

Donald L. Baars · 1983

A key geological reference for understanding the uplift, stratigraphy, tectonics, and erosional history of the Colorado Plateau.

knowledge
The Control of Nature

The Control of Nature

John McPhee · 1989

Three deeply reported narratives about humanity's attempts to stop rivers, lava, and debris flows — and what the land does in return. A masterwork of geological journalism that asks whether nature can ever truly be controlled.

tone storytelling philosophy knowledge
The Exploration of the Colorado River

The Exploration of the Colorado River

John Wesley Powell · 1875

Powell's original account of the first scientific expedition through the Grand Canyon, documenting the geology, natural history, and challenges of navigating the unknown Colorado River.

knowledge storytelling cultural context
The Secret Knowledge of Water

The Secret Knowledge of Water

Craig Childs · 2000

Craig Childs explores the hidden water sources and desert hydrology of the American Southwest, revealing how water shapes and sustains life in the most arid landscapes on Earth.

tone philosophy knowledge
Where the Old West Stayed Young

Where the Old West Stayed Young

John Rolfe Burroughs · 1962

A historical portrait of the ranching and outlaw culture of Browns Park and the remote canyons of the Colorado Plateau, illuminating how geography shaped the final stronghold of the old frontier.

cultural context storytelling knowledge
Upstream B Section
Downstream Browns Park