Lower Colorado River

Lower Colorado River

Lees Ferry, Marble Canyon and the Grand Canyon: since 1963 the river's flow is set mostly by Glen Canyon Dam, but floods still pour in from the side canyons.

Map of the Lower Colorado RiverKaibab PlateauCoconino PlateauUinkaret MountainsColorado RiverLees FerryNavajo BridgePhantom RanchKanabFredoniaKanab Creek mouthSupaiDiamond CreekPearce Ferry25 miles
Lower Colorado River. River lines from the USGS National Hydrography Dataset.
Looking into Marble Canyon, with Shinumo Altar in the distance, 1870s.
Looking into Marble Canyon, with Shinumo Altar in the distance, 1870s.Powell Survey (John K. Hillers). U.S. National Archives, public domain · source

People and the river

The Colorado at the foot of Toroweap, Grand Canyon, photographed by the Powell Survey in the 1870s.
The Colorado at the foot of Toroweap, Grand Canyon, photographed by the Powell Survey in the 1870s.Powell Survey (John K. Hillers). U.S. National Archives, public domain · source
  1. For centuriesAncestral Puebloans, and the Havasupai, Hualapai, Hopi, Navajo and Southern Paiute peoples, lived in and around the canyon.1
  2. 1869Powell's expedition made the first recorded trip through the Grand Canyon.2
  3. 1872John D. Lee started his ferry at Lees Ferry, still the starting point for Grand Canyon river trips.3
  4. 1919Grand Canyon became a national park.1
  5. 1963Glen Canyon Dam began holding back the river's floods and sediment.4

Biggest flows

Major Powell's boat, his armchair lashed on, in the Grand Canyon on the 1871-72 expedition.
Major Powell's boat, his armchair lashed on, in the Grand Canyon on the 1871-72 expedition.Powell Survey (John K. Hillers). U.S. National Archives, public domain · source
210,000–300,000cfs
Colorado at Lees Ferry, 1884: the largest flood of the historic record5,6
estimated
170,000–220,000cfs
Colorado at Lees Ferry, June 1921: the largest gauged flood5
estimated
over 490,000cfs
a flood 1,200–1,600 years ago, from canyon deposits5
estimated
~51,000cfs
Colorado near Grand Canyon (Phantom Ranch), Oct 23, 2026, fed by the Little Colorado and Paria7
provisional reading

Measured: a USGS gauge reading. Estimated: reconstructed after the fact from high-water marks or flood deposits. Provisional: USGS readings not yet reviewed.

Floods that mattered

Aug 2008: Havasu Creek

Overnight storms and a small dam failure upstream flooded Havasu Canyon; more than 400 campers and residents were evacuated from Supai.8,9

Oct 2026

The Little Colorado ran near 18,000 cfs at Cameron and the Paria above 5,000 cfs, pushing the Colorado at Phantom Ranch past 50,000 cfs (provisional).7

The Colorado River in the Grand Canyon and its Tributaries

Map of the Colorado River in the Grand Canyon and its tributaries in northern Arizona, with Kaibab Plateau, Coconino Plateau, Shivwits 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. NPS: Grand Canyon history and culture
  2. Utah Geological Survey: Powell's 1869 river journey
  3. NPS: Crossing of the Fathers, Explorers and Settlers
  4. Bureau of Reclamation: Glen Canyon Unit
  5. USGS: Floods of the Colorado River at Lees Ferry, reanalysis (PP 1677)
  6. Eric Kuhn: Floods on the Colorado
  7. NOAA National Water Model archive of USGS 15-minute readings (provisional)
  8. NBC: Grand Canyon flooding forces evacuation of 400 people (Aug 2008)
  9. Supai, Arizona (Wikipedia)

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