Floods of November 1965 to January 1966 in the Gila River Basin, Arizona and New Mexico, and Adjacent Basins in Arizona GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1850-C Floods of November 1965 tc January 1966 in the Gila River Basin, Arizona and New Merico, and Adjacent Basins in Arizona By B. N. ALDRIDGE FLOODS OF 1965 IN THE UNITED STATES GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1850-C UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1970 UNITED STATES DEPARTMENT OF THE INTERIOR WALTER J. HIGKEL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director For sale by the Superintendent of Documents, U.S. Government Printing O<"ice Washington, D.C. 20402 - Price $2.50 (paper cover) CONTENTS Page Abstract._-_______--_______-____-_-_-__----__--___--_-_----___-_ Cl Introduction. __-__________________-___-_--------_---_-_-_--_--____ 2 Acknowledgments. ____________________________________________ 2 Geographic setting.___________________-_--__-_-___---_--_---____-__ 3 Storms and weather conditions.___________-_---_______-_-_____--____ 3 Storms of November 22-25, 1965________._..___.-___---_-______ 6 Storms of December 9-11 and December 14-15, 1965.______ _______ 7 Storm of December 22-23, 1965_____.______-__-_-______-_.____ 10 Storm of December 29-30, 1965.______._.______________ 10 Floods and runoff_---_____-___-_-_-_----_----_-_---__-------_-_--__ 11 Gila River basin above Coolidge Dam______----____-_-----_---_- 12 Gila River basin between Coolidge Dam and Salt River_____ ________ 14 Salt River basin and Gila River below Salt River. -____-______.-__ 17 Reservoir inflow________-______-_______--_________-_-_-_- 17 Regulated discharge at Stewart Mountain and Bartlett Dams... 18 Stages and discharges downstream from Granite Reef Dam during the Phoenix flood._____--______-_.._-__--____-____- 19 Effects of the Phoenix flood_____-_.__-___-__._____---_-- 22 Reduction in peak discharge by storage in reservoirs. ___.. _____ 25 Comparison with previous floods. _________________________ _. 25 Effects of the floods on ground-water levels.__________________________ 29 Streamflow data at gaging stations and miscellaneous measuring sites..__.. 31 Determination of flood discharges_________-___-___-___-_______,__ 31 Summary of flood stages and discharges.__----__---__---_-_______ 31 Explanation of station data_-__-_-__-_---__-----_-__---_-_------ 33 Station data._________________________________________________ 41 References cited.__________________________________________________ 171 Index... _._...___.... ... ..__.....___. ..........._._...._... 173 ILLUSTRATIONS [Plates in pocket] PLATE 1. Map showing area of report and sites where hydrologic data were collected, Gila River basin, Arizona and New Mexico. 2. Maps showing precipitation, November and December 1.965, in the Gila River basin, Arizona and New Mexico. 3. Hydrographs showing discharge at selected gaging stations, Santa Cruz and Gila River basins, Arizona and New Mexico. 4. Graphs showing discharge and stage at selected stations on the Salt, Verde, and Gila Rivers, Ariz. 5. Photographs and flood map of the Salt River in the Phoenix metro­ politan area, Arizona. 6. Maps and hydrographs showing daily mean discharge and rise in water levels at selected wells along Rillito and Tanque Verde Creeks and Salt and Gila Rivers, Ariz. in IV CONTENTS Page FIGURE 1. Map showing ma] or areas where large amounts cf runoff originated from storms of November and December 1965-_ C4 2. Profile of flood crest on Rillito Creek and the Santa Cruz River. _ 16 TABLES Page TABLE 1. Snowfall and snow on the ground, December 1965___________ C8 2. Snow-survey data, December 1965-_______________________ 10 3. Times when the Phoenix flood reached different points on the Salt and Gila Rivers__-_---__. ________-__..____ 21 4. Runoff of the Salt and Gila Rivers downstream from Granite Reef Dam____________-__-___________-__._____________ 22 5. Summary of damages from the Phoenix flood along the Salt and Gila Rivers_______________________________________ 24 6. Discharge data for major floods, Salt River and main tribu­ taries, 1888-1965._________________________ 26 7. Sources of data for major floods, Salt River and main tribu­ taries, 1888-1965_._____________________ 28 8. Representative rises in ground-water levels along major flood plains in the Gila River basin, spring 1965 to spring 1966_ 30 9. Summary of flood stages and discharges.___________________ 36 FLOODS OF 1965 IN THE UNITED STATES FLOODS OF NOVEMBER 1965 TO JANUARY 1966 IN THE GILA RI^ER BASIN, ARIZONA AND NEW MEXICO, AND ADJACENT BASINS IN ARIZONA By B. N. ALDREDGE ABSTRACT Above-normal precipitation, which fell over much of Arizona and New Mexico in November and December 1965 during five distinct storm periods, caused flood­ ing in several parts of the Gila River basin. The floods caused about $5 million in damages in the Gila River basin upstream from Salt River anc' about $6 million in damages along the Salt River and Gila River below Salt River. The most significant flood was the Phoenix flood, which resulted from the release of water from storage reservoirs on the Salt and Verde Rivers. A large volume of fall and winter runoff added to a large carryover storage from the preceding spring raised the contents of the reservoirs to an unusually high level for De­ cember. The regulated discharge in the Salt River below Granite Ree* Dam was the highest since the reservoir system was completed-in 1939; however, several larger floods had occurred in earlier years. The maximum discharge of the Salt River through the downtown £ rea during the Phoenix flood was 66,000 cfs (cubic feet per second) on December 31, 1965. Without the storage provided by the upstream reservoirs, the peal- discharge during the flood would have been more than 80,000 cfs, and the peak discharge on December 23 might have exceeded 120,000 cfs. If the reservoirs were not present, a peak discharge of 66,000 cfs, equal to that of December 31, would occur on an average of about once every 6 years. The peak discharge during the Phoenix flood was reduced only sl'ghtly as it traveled from Granite Reef Dam on the Salt River to Gillespie Dam on the Gila River; however, the volume of flow was reduced considerably in the same reach. More than 500,000 acre-feet of water passed over Granite Reef Dam, but only 37,000 acre-feet of water reached the mouth of the Gila River. Rises in ground- water levels in the flood plains indicate that a large amount of the streamflow loss went to ground-water recharge. Cl C2 FLOODS OF 196i5 IN THE UNITED STATES INTRODUCTION Five major storms moved into Arizona and western New Mexico from the Pacific Ocean in November and December 1965. From the last week in November until the end of December, stcrms were a weekly occurrence, and rain or snow fell on about four out of every 10 days. The major storms occurred November 22-25, December 9-11, December 14 15, December 22-23, and December 29-30, Only the last two storms caused appreciable flooding, although the earlier storms did cause extremely high flows in some areas. The earlier storms set the stage for the floods later in December by thoroughly soaking the soil at low altitudes and by depositing snow in the mountains. The most significant flood with respect to property damage began December 31, when water was released from storage reservoirs into the normally dry channel of the Salt River below Granite Ree f Dam; the reservoirs were full because of the unusually heavy autumn and winter runoff and the above-normal carryover storage from the 1965 irriga­ tion season. The flood, which is called the Phoenix flood, caused severe damage along the Salt River below Granite Reef Dam and along the Gila River below Salt River. Flood runoff continued until May 1966 in the lower reaches of the Gila River. Severe flooding also occurred in the Gila River basin upstream from the Salt River following the storm of December 22-23 and in the Gila River basin upstream from Coolidge Dam following the storm of December 29-30. The purpose of the report is to summarize the conditions preceding the floods, to give a factual account of the floods, to describe the floods in proper perspective to past floods, and to show the effects of the reservoirs on the floods in the Salt and Verde Rivers. Although the report deals primarily with the Phoenix flood, it contains data for the other floods (fig. 1). ACKNOWLEDGMENTS The author wishes to acknowledge the assistance given by L. C. Goldsmith, hydrology analyst, Salt River Valley Water Users'- Asso­ ciation; Paul Kangeiser, State climatologist, U.S. Weathe*' Bureau; R. W. Enz, snow-survey supervisor, U.S. Soil Conservation Service; Ralph Edde, supervisor of county mapping, Photogrammetry and Mapping Division, Arizona Highway Department; and the Los An­ geles district, U.S. Army Corps of Engineers, who supplied hydrologic data concerning the area. GILA RIVER BASIN, ARIZONA AND NEW MEXICO C3 GEOGRAPHIC SETTING The Mogollon Rim extends across the eastern half of Arizona and divides the north-flowing tributaries of the Little Colorado River from the south-flowing tributaries of the Verde, Salt, and Gila Rivers (pi. 1). The Mogollon Rim rises sharply above the surrounding area and is generally at altitudes between 6,500 and 7,500 feet. TYQ, White Mountains in Arizona and the Gallo and Mangas Mountain? in New Mexico form the eastern end of the divide between the Gila and Little Colorado Rivers. The floods of November 1965 to January 1966 originated along this divide, in the rugged mountainous area south of the divide, and in a few small areas in southern Arizona (fig.