138 BULLETIN OF THE BUREAU OF FISHERIES. 



DESCRIPTION OF LAKE TAHOE. 



Location, size, and physical features. — Lake Tahoe is situated in eastern Cali- 

 fornia and western Nevada. The boundary line between these two states passes 

 through it in a north and south direction, only a short distance west of the eastern 

 shore, so that more than two-thirds of the area of the lake lies in California and less 

 than one-third in Nevada. The thirty-ninth parallel of latitude crosses the southern 

 end. To quote from Le Conte (1883, p. 506): 



This lake, the largest and most remarkable of the mountain lakes of the Sierra Nevada, occupies 

 an elevated valley at a point where this mountain system divides into two ranges. It is, as it were, 

 ingulfed between two lofty ridges, one lying to the east and the other to the west. As the crest of the 

 principal range of the Sierra runs near the western margin of this lake, this valley is thrown on the 

 eastern slope of this great mountain system. 



The greatest dimension of the lake is in a north-south direction, and is said to be 

 aoout 22.5 miles; its greatest width is about 13 miles, and it has an area of about 195 

 square miles. The tributary watershed has an area of more than 300 square miles 

 exclusive of the area of the lake, the whole basin having an area of a little more than 

 500 square miles. The altitude of the lake is 6,225 feet and the greatest depth found 

 bv Le Conte was 1,645 feet (501 meters). 



Affluents. — Le Conte further saj's: 



Probably more than a hundred affluents of variouscapacities, deriving their waters from the amphi- 

 theater of snow-clad mountains which rise on all sides from 3,000 to 4,000 feet above its surface, con- 

 tribute their quota to supply the lake. The largest of these affluents is the upper Truckee River, 

 which falls into its southern extremity. The only outlet to the lake is the Truckee River, which 

 carries the surplus waters from a point on its northwestern shore out through a magnificent mountain 

 gorge, thence northeast, through the plains of Nevada, into Pyramid Lake (and Winnemucca Lake). 

 This river in its tortuous course runs a distance of over one hundred miles. 



Generally a large amount of snow falls on the Iakeward slopes of the surround- 

 ing mountains and thus supplies many of these affluents with water during the entire 

 summer. Muir (1878) states that observations were made at a station on the west 

 shore of the lake and it was found that the amount of snow, measured as it fell, was 

 a little less than 10 feet one winter and over 47 feet another winter. On the 21st of 

 June, l!»t)4, vast areas were found along the upper courses of some of the affluents 

 where the snow was from 5 feet to probably 30 feet deep. The warm summer's sun 

 was melting this snow rapidly and by midafternoon these streams had increased 

 enormously in size. 



Variations of level. — On this subject Le Conte says (1884, p. 41): 



As might be expected, the waters of Lake Tahoe are subject to fluctuations of level, depending 

 upon the variable supplies furnished by its numerous affluents. In midwinter, when these streams are 

 bound in icy fetters, the level falls; while in the months of May and June, when the snows of the 

 amphitheater of mountain slopes are melting most rapidly, the level of the lake rises ami a maximum 

 amount of water escapes through its outlet. According to the observations of Capt. John McKinney, 

 made at his residence on the western shore of the lake, the average seasonal lluctuation of level is 

 about 0.61 meter (2 feet); but in extreme seasons it sometimes amounts to 1.37 meters (4.5 feet). 



As a dam several feet in height is now maintained at the outlet, the fluctuations at 

 present may be greater than those recorded above. According to Mr. Murphy, who 

 has lived many years on the shores of the lake, the water was about 3 feet higher 



