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 m3/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.
|Title||When the blue-green waters turn red: Historical flooding in Havasu Creek, Arizona|
|Authors||Theodore S. Melis, William M. Phillips, Robert H. Webb, Douglas J. Bills|
|Publication Subtype||USGS Numbered Series|
|Series Title||Water-Resources Investigations Report|
|Record Source||USGS Publications Warehouse|