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| PUBLICATIONS—Water-Resources Investigations Report |
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By Theodore S. Melis, William M. Phillips, Robert H. Webb, and Donald J. Bills
U.S. Geological Survey Water-Resources Investigations Report 96—4059
Havasu Creek, the second largest tributary of the Colorado River in Grand Canyon National Park, attracts numerous visitors each year owing to its spectacular scenery. Perennial streamflow seldom exceeds 2 cubic meters per second (m3/s), but supports important stands of riparian vegetation, forms unique travertine pools, and spills over spectacular waterfalls. Havasu Canyon is home to the Havasupai Tribe, consisting of 423 members living in Supai, Arizona. Flooding in Havasu Creek poses a hazard to both visitors and residents of Supai. Frequent, large floods occurred in winter and summer during the late 19th and early 20th centuries; the largest occurred in January 1910. Smaller, summer floods occurred between 1935 and 1990. In September 1990, the largest flood in Havasu Creek since 1935, and possibly 1910, was generated by intense thunderstorms that lasted several days. The 1990 flood peaked at 575 m33/s, caused severe damage to Supai, killed hundreds of ash trees (Fraxinus sp.), and altered travertine deposits in lower Havasu Canyon. Smaller floods in July 1992 and February 1993 also damaged Supai, eroded waterfalls, destroyed riparian vegetation, filled pools with gravel, and deposited coarse debris in the Colorado River. Most ash trees in Havasu Canyon germinated after 1940; peak recruitment occurred in the late 1960s and early 1970s, possibly in response to human disturbance. Nearly 80 percent of historical Havasu Creek floods have occurred during or immediately following El Niño years. Recent 1990s flooding reflects the flood regime of the first third of the 20th century, and frequency of intense daily precipitation at stations near Havasu Creek has followed patterns in recent flood frequency.
Frontispiece
Abstract
Introduction
Physical Setting of Havasu Creek
Recreation and Habitation Within Havasu Canyon
Purpose and Scope
Sources of Information on Floods in Havasu Creek
Units and Place Names
Acknowledgments
Methods
Historical Accounts of Flooding
19th-Century Flooding
Floods of 1904-1905
The Flood of January 2, 1910
The Flood of February 23, 1920
The Floods of August 1921
The Flood of August 1, 1928
The Flood of July 1935
Regional Flooding of 1939
Flooding from 1940 to 1970
Small Floods in the summer of 1970
The Floods Between 1970 and 1990
The Flood of September 3, 1990
The Flood of July 25, 1992
The Flood of February 20, 1993
Summary of Historic Flood Accounts
Photographic Evidence of Flood Damage in Havasu Canyon
Havasu Canyon near Supai
Fiftyfoot Falls
Navajo Falls
Havasu Falls
Havasupai Campground
Mooney Falls
Mooney Falls to Beaver Falls
Beaver Falls
Beaver Falls to the Colorado River
The Confluence of Havasu Creek and the Colorado River
Summary of Photographic Evidence
Dendrochronology of Ash Trees
Response of Riparian Forest to Flooding
Summary and Discussion
Hydroclimatology of Floods in the Havasu Creek Drainage Basin
Summary and Discussion
Discussion and Conclusions
References Cited
For more information about USGS water resources studies in Arizona, visit the USGS Arizona Water Science Center home page: http://az.usgs.gov
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