Lake Powell

Where Lake Powell's water comes from

The reservoir behind Glen Canyon Dam, filling about 186 miles of Glen Canyon and its side canyons.

Map of the Lake PowellLake PowellHenry MountainsColorado RiverNavajo Mountain 10,346 ftMount Ellen 11,522 ftMount Hillers 10,723 ftHanksvilleHiteBullfrog / Halls CrossingEscalante (Hwy 12)Mexican HatRainbow BridgeAntelope CanyonLees FerrySan Juan RiverEscalante RiverDirty Devil RiverNavajo CreekWahweap CreekBullfrog CreekNorth Wash25 miles
Lake Powell. River lines from the USGS National Hydrography Dataset.
Lake Powell and Glen Canyon Dam, from the EPA's Documerica project (1971–1977).
Lake Powell and Glen Canyon Dam, from the EPA's Documerica project (1971–1977).EPA Documerica. U.S. National Archives, public domain · source

Headwaters

Probably Narrow Canyon, just above where the Dirty Devil comes in, now the head of Lake Powell; 1870s.
Probably Narrow Canyon, just above where the Dirty Devil comes in, now the head of Lake Powell; 1870s.Powell Survey (John K. Hillers). U.S. National Archives, public domain · source

Rocky Mountain snow

Most of the water in Lake Powell is snowmelt from the Rocky Mountains of Colorado, Wyoming and Utah, carried by the Colorado and Green rivers. They meet in Canyonlands and enter the lake below Cataract Canyon, near Hite. Most of the year's inflow arrives from April to July.1,2

The San Juan

The San Juan, from the San Juan Mountains by way of Navajo Lake and the Animas, enters its own long arm of the lake. It is the lake's second largest river.3,1

Desert rivers and side canyons

The Escalante and the Dirty Devil bring smaller amounts from the high plateaus of southern Utah. Dozens of side canyons, from North Wash to Wahweap, are dry most of the year and run only after storms.4,5,6

The river, top to bottom

  1. HiteThe Colorado (with the Green) enters from Cataract Canyon; the Dirty Devil joins.
  2. North Wash, Trachyte & White CanyonSide canyons near Hite.
  3. Bullfrog & Halls CrossingBullfrog and Halls creeks join; ferry across the lake.
  4. Escalante armThe Escalante River comes in from the north.
  5. San Juan armThe San Juan joins from the east.
  6. Navajo & Antelope creeksSide canyons near Page.
  7. Wahweap & Glen Canyon DamThe lake ends at the dam; water is released to Lees Ferry and the Grand Canyon.

Main tributaries

StreamJoinsNotes
Colorado RiverHiteWith the Green, most of the lake's water.
San Juan RiverSan Juan armSecond largest; snowmelt plus fall storms.
Dirty Devil RiverNear HiteFrom the Fremont River and Muddy Creek.
Escalante RiverEscalante armSmall but flashy.
Side canyonsAll along the lakeNorth Wash, Halls, Bullfrog, Navajo, Wahweap and others: dry until a storm.

Why it matters for floods

The lake rises slowly with each spring's snowmelt from the Rockies. Glen Canyon Dam holds those floods; in 1983 a huge snowmelt year filled the lake and the spillways were damaged. Summer thunderstorms flash the side canyons, which can be dangerous for hikers and boaters even when the lake itself barely moves.2,1 The live map watches the gauges along the way.

Lake Powell and its Tributaries

Map of Lake Powell and its tributaries in southern Utah and northern Arizona, with Henry Mountains, Kaiparowits Plateau: rivers, side canyons, contour lines and summit elevations, in a classic survey style.
A classic map of the river and the mountains around it. Full size · Vector (SVG) · © 2026 Southwest River Watch
Sources
  1. Lake Powell (Wikipedia)
  2. Bureau of Reclamation: Glen Canyon Unit
  3. San Juan River (Wikipedia)
  4. Escalante River (Wikipedia)
  5. Dirty Devil River (Wikipedia)
  6. NPS: Glen Canyon National Recreation Area

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