242 



REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



rary expansion i)roduciug secondary maxima in 1876 and 1S87, until in 

 the fall of 1898 it stood at about 2.J feet on the Garfield gauge, or 

 barely a foot above the level of the corresponding season of 1850. 



In addition to the nonperiodic oscillation described, there is also an 

 annual fluctuation, due to the temperature and precipitation character- 

 istics of the region, the lake reaching its maximum elevation in June 

 and its minimum in November. This is referred to, as follows, by 

 G. K. Gilbert, in his monograph on Lake Bonneville: 



The cause of this annual variation is at once apparent. The chief accessions of 

 water to the lake are from the melting of snow on the mountains, and this occurs in 

 the spring, occasioning the rise of the water from March to June. Water escapes 

 from the lake only by evaporation, and evaporation is most rapid in the summer. 

 Before the inllux from melting snow has ceased it is antagonized by the rapidly 

 increasing evaporation, and as soon as it ceases the surface is quickly lowered. In 

 autumn the rate of evaporation gradually diminishes; in November it barely equals 

 the tribute of the spring-fed streams, and in wiuter it is overpowered by such 

 aqueous product of mountain storms as is not stored up in snow banks. 



There is still another variation affecting the lake level locally, 

 although its average level is not disturbed. Under the influence of 

 strong winds the water is rolled uj) on the shelving lee shores to a 

 height of several feet above the normal water line, while on the oppo- 

 site or windward shores there is a corresponding depression. Even 

 with gentle winds, not exceeding 6 or 8 miles per hour in velocity, the 

 writer has known the water to rise an inch or two on the flats forming 

 the eastern shore of the lake between the deltas of the Bear and Weber 

 rivers. 



Each of these variations in the lake's level has an important indirect 

 bearing on the subject of the present investigation, the first two aflect- 

 ing the salinity of the lake both generally and locally, while the third 

 has a jiurely local efiect. It is evident that as the water rises, during 

 either an annual or a nonperiodical elevation, the general density of 

 the lake water must decrease, for the increased volume is due to the 

 addition of fresh water, and the total quantity of salt in the lake 

 remains practically, though not absolutely, the same. During a period 

 of subsidence the contrary is true, although some of the saline matter 

 is left by desiccation upon the shores from which the water has receded, 

 part of this being gradually returned to the lake by leaching and part 

 of it being covered and entrapped in the soil. There are no data avail- 

 able to illustrate the effects of the annual oscillation, but the effects of 

 the nonperiodic fluctuation are shown in the following table: 



Date. 



1850 



3869 (summer). ., 

 1873 (Augu.st) ... 

 1885 (December). 

 1889 (August).., 

 1892 (August) ... 

 1897 (November) 



Sp. gr. 



1.170 

 1.111 

 1.102 

 1.122 

 1.157 

 1.156 

 1.168 



Locality. 



Garfield Beach. 



Authority. 



L. D. Dale. 

 O. D. Allen. 

 H. Bassett. 

 J. E. Talmage. 



Do. 

 E. Waller. 

 H. F. Moore. 



