Colorado River
Colorado River
Map of the Colorado Watershed
Origin
La Poudre Pass Lake
Mouth
Gulf of California
Length
2,330 km (1,450 mi)
Source elevation ~2700 m (~9000 ft)
Avg. discharge
620 m³/s (22,000 ft³/s)[1]
Basin area
629,100 km² (242,900 mi²)
Downstream view of the Colorado River at
river mile 175 in the Grand Canyon
The Colorado River (’Aha Kwahwat in
Mojave)[2], or the Red River, is a river in the
southwestern United States and northwest-
ern Mexico,
approximately 1,450 miles
(2,330 km) long, draining a part of the arid
regions on the western slope of the Rocky
Mountains. The natural course of the river
flows into the Gulf of California, but the
heavy use of the river as an irrigation source
for the Imperial Valley has desiccated the
lower course of the river in Mexico such that
it no longer consistently reaches the sea.
The Colorado River drains 242,900 sq mi
(629,100 km²). Total flows of the river range
from 4000 cubic feet per second (113 m³/s) in
droughts to 1,000,000 ft³/s (28,000 m³/s) in
severe floods. With the construction of
massive power dams on the lower course of
the river, flows of over 70,000 ft³/s (2000 m³/
s) are unusual. The mean flow of the river
was 22,000 ft³/s (620 m³/s) during the period
between 1903-34. From 1951-80, the average
flow was less than 4,000 ft3/s.[1] Historically
the flow was much higher before water usage
began in the basin.
History
Early records
The existence of the Colorado River was first
noted in the records of written history in
September, 1539, when Francisco de Ulloa
sailed to the head of the Gulf of California
and rowed a short distance upstream.[3] It
was next seen by Hernando de Alarcon who
in 1540 led the maritime contingent of
Coronado’s expedition. The plan was to meet
the land based force and resupply them. Alar-
con ascended the river about 85 Spanish
miles to the limit of navigation near present-
day Yuma, Arizona. He waited for Coronado,
but eventually despaired, cached some sup-
plies and correspondence, left a note on a
tree, and departed. Coron