(1956; minimum flow was 11.1 c.f.s. (1961). 

 The 13 -year mean run-off was 16,219 acre feet. 

 Maximum value of 25,378 acre feet was in 1956; 

 the lowest, 8,027 acre feet, was in 1961. 



The temperature and flow data in tables 

 4,5, and 6 were formulated on a May through 

 April basis and are presented in this manner for 

 convenience in relation to the experimental fish 

 testing program of the Station . 



Figure 4 illustrates the general trend for 

 the mean annual air and water temperatures for 

 the 13 -year period and clearly indicates the se - 

 verity of the winter of 1951-52 with its extremely 

 low air and water temperatures . A general but 

 sharp rise in air and water temperature was evi- 

 dent between 1956 and 1960 . From 1960 through 

 1962 temperatures had begun to decline to near 

 average values . 



Figure 5 shows the relation of mean monthly 

 rate of flow to air and water temperatures, il - 

 lustrated by maximum and minimum run -off 

 years for the 13 -year period. Even though the 

 run -off was markedly different between the two 

 years it is evident that snow melt is initiated and 

 flow increases near the latter part of April when 

 mean monthly air and water temperatures reach 

 40° F. Run-off usually peaks in late June and 

 decreases sharply through the months of July 

 and August. Flow begins to level off during 

 September, at which time cooler temperatures 

 at the higher elevations prevent any further snow 

 melt and the flow stablizes at a low level (unless 

 unusual weather conditions prevail) until the 

 following spring. Convict Creek is like other 

 small lotic situations in that the water temper- 

 ature closely parallels the air temperature . 



The maximum air temperature recorded in 

 the 13-year period was 94* F. on June 20, 1961; 

 minimum air temperature recorded was -22.0*F. 

 on January 4, 1955; maximum water temperature 

 recorded was 74° F. on August 11, 1960; mini- 

 mum water temperatures of 32° F. are recorded 

 every year during the winter and early spring 

 months . 



Maximum rate of flow recorded in the 13- 

 year period was 183.9 c.f.s. on June 25, 1958; 



minimum rate of flow recorded was 1.3 c.f.s. 

 on January 10, 1951. In the 35 "years the meter 

 station has been in operation the maximum flow 

 recorded was 234 c.f.s. on June 29, 1932; mini- 

 mum flow recorded was 1.3 c.f.s. on January 

 10, 1951. 



Extreme variation in temperature and pre- 

 cipitation was evident during this 13-year period. 

 The winter of 1951-52 was by far the most severe, 

 with snow depths between 5 and 15 feet (fig. 3), 

 gusty winds to 80 m.p.h. , and below-normal 

 temperatures. U.S. Highway 395 was closed 

 periodically throughout this winter . During the 

 latter half of December 1955 a large Pacific 

 warm front originating east of Hawaii failed to 

 follow the normal pattern of moving in a north- 

 eastern direction and swung due east, inundating 

 this area with heavy rain that lasted for 36 hours 

 and eventually turned into heavy, wet snow which 

 continued for another 48 hours. Flooding was 

 extensive , and sleet and snow snapped power and 

 telephone lines and even toppled power poles. 

 The winters of 1959-60 and 1960-61 were rela - 

 tively mild with below-normal precipitation. 

 Although the long-range forecast for the winter 

 of 1961-62 was for a continued pattern of below 

 normal precipitation, between February 7 and 

 February 14, 1962, a persistent low-pressure 

 system dumped 53 inches of snow in the immedi- 

 ate area. This situation was paralleled in Feb- 

 ruary 1963 except that heavy amounts of rain 

 followed the heavy snowfall and reduced the 

 snowpack to one-fourth its original depth, and 

 flooding was common throughout the area. 



Precipitation was measured during 1 year, 

 October 1, 1957, tJirough September 30, 1958, 

 by means of a standard Weather Bureau type 8- 

 inch rain gage. A total of 17.4 inches of pre- 

 cipitation was measured which included approx- 

 imately 200 inches of snow with a water content 

 of 11.2 inches . Rain made up the rest of the 

 precipitation, 6.2 inches, and was primarily 

 from thunderstorms . The first snowfall of this 

 period was on October 20, 1957, and the last on 

 April 7, 1958. Heaviest snowfall recorded was 

 26 inches (water content of 2.75 inches) on 

 March 15 and 16, 1958. Heaviest rainfall, amount- 

 ing to only 0.35 inches, was recorded on August 

 18 , 1958 . This was probably an average year of 

 precipitation. 



