THE AUTHORS 



RESEARCH SUMMARY 



JOEL E. FLETCHER, professor of hydrology— emeri- 

 tus, Utah Water Research Laboratory, Utah State 

 University, Logan, conducted water research with 

 the U.S. Department of Agriculture in Tucson, Ariz.; 

 Gallup, N. Mex.; Davis, Calif.; and Boise, Idaho. His 

 principal interests have been rainfall- run off relations, 

 soils and instrumentation, before coming to Utah. 



A. LEON HUBER, assistant professor, Utah Water 

 Research Laboratory, conducted water research 

 with the U.S. Department of Agriculture in Idaho 

 before coming to Utah State University in 1961. 



EUGENE E. FARMER, forest hydrologist on the Water- 

 shed Protection and Rehabilitation research work 

 unit at Logan, Utah, joined the staff of the Inter- 

 mountain Station in 1 964. His primary investigations 

 have been in the areas of mined land reclamation and 

 hydrology and in mountain rainfall characteristics 

 and soil erosion. 



KEITH R. MCLAUGHLIN is presently with the USDA 

 Forest Service, Rocky Mountain Region, Medicine 

 Bow National Forest, Laramie, Wyo., as a forest hy- 

 drologist. In his past 6 years with the agency, he has 

 been assigned to the Cache and Manti-LaSal Na- 

 tional Forests in Utah, respectively. He received a 

 bachelor of science degree in forest watershed 

 management from the University of Minnesota in 

 1970. 



JOHN RECTOR is the forest hydrologist on the Manti- 

 LaSal National Forest in Price, Utah. Previously, he 

 has had assignments with the Tonto National Forest 

 in Phoenix, Ariz., the Dixie National Forest, and Inter- 

 mountain Region headquarters in Utah. He received 

 a bachelor of science degree in forest management 

 from Michigan Technological University, 1966, and 

 a master of science degree from the University of 

 Arizona in watershed management and soil physics, 

 1968. 



LARRY J. SCHMIDT is presently with the Forest Ser- 

 vice, Southwestern Region, Albuquerque, N. Mex., as 

 regional hydrologist. In his past 10 years with the 

 agency, he has been assigned to the Intermountain 

 Region and to the Manti-LaSal and Toiyabe National 

 Forests in Utah and Nevada, respectively. He re- 

 ceived a bachelor of science degree in forest water- 

 shed management from Utah State University in 

 1967. 



ACKNOWLEDGMENT 



Precipitation data for this report were collected on 

 the Straight Canyon barometer watershed, Manti-LaSal 

 National Forest. The authors appreciate the coopera- 

 tion of personnel on the Manti-LaSal National Forestfor 

 providing the data base. This watershed is part of a 

 national program to tailor, apply, and demonstrate 

 research-derived management prototypes in broad- 

 scale forest management programs. This publication is 

 part of the barometer program to characterize the 

 hydrologic and climatic environment of the area. 



This paper presents results of data analyses for 10 

 precipitation intensity stations at Straight Canyon baro- 

 meter watershed in central Utah located at elevations 

 between 7,250 ft (2 2 1 m) and 1 0,400 ft (3 1 70 m) m.s.l. 

 All data were collected between 1 967 and 1 974 during 

 the months of May to October, with all records complete 

 for July, August, and September. 



The following analyses were made: (1) record con- 

 sistency, (2) definition of local precipitation zones, (3) 

 intensity-duration-frequency characteristics, (4) 24- 

 hour precipitation depths, (5) monthly depths and num- 

 bers of storms, (6) storm occurrence by time of day, (7) 

 storm occurrence by storm duration, (8) annual maxi- 

 mum erodent values for Straight Canyon gages, Davis 

 County experimental watershed, and Great Basin ex- 

 perimental area. The precipitation zone between 7,000 - 

 8,000 ft (2 1 34 - 2 438 m) m.s.l. is expected to receive the 

 highest rainfall intensities. Rainfall intensity decreases 

 with elevation. The zones receiving the greatest rainfall 

 receive the lowest intensities. The major portion of 

 storms occur between the hours of 1 1 :00 a.m. and 3:00 

 p.m. Eighty percent of the storm have durations shorter 

 than 2.8 hours, with the highest elevations having the 

 shortest durations. Erodent values are inversely propor- 

 tional to the elevation and penetration past the uplift 

 barrier. The use of erodent values is described. 



CONTENTS 



Page 



INTRODUCTION 1 



METHODS 2 



Record Consistency 2 



Frequency Analysis 2 



Precipitation Zones 3 



24-Hour Precipitation Depth 3 



Average Monthly Depth and Number 



of Storms 3 



Storm Occurrence by Hour 3 



Storm Penetration 3 



Erodent, R, Values 3 



Storm Duration 4 



RESULTS 4 



Consistency Test 4 



Precipitation Zones 4 



Intensity-Duration-Frequency 



Characteristics 4 



24-Hour Precipitation Depth 5 



Average Monthly Depth and Number 



of Storms 5 



Storm Occurrence by Hour 6 



Storm Penetration 6 



Erodent Values, R 6 



Use of R Values 6 



Storm Occurrence by Storm Duration 9 



DISCUSSION 10 



PUBLICATIONS CITED 11 



