Lake Louise, Alberta, Canada. 379 



lake by the stream throughout the year probably does not 

 exceed 90 parts per million. Most of the sediment trans- 

 ported into the lake is deposited on the bed of the lake, 

 for the outlet stream is nearly clear. 



The inflow into the lake by the stream from Victoria 

 glacier in June, 1921, during a period of moderate rain- 

 fall and melting of the ice, was estimated at 85 c. ft. per 

 sec. Four determinations by Sherzer, in 1904, upon the 

 inflow at the head of the lake gave an average of 80 

 c. f. s. ; two at the outlet gave an average of 88 c, f. s., 

 the small additional flow coming from Mirror Lake and 

 Lake Agnes. 5 The inflow from these lakes is partly by 

 underground passages and the water is clear. The 

 greater part of the flow from the lake is carried by two 

 pipes, one 33 and the other 20 inches in diameter. It is 

 stated by Mr. Gartom that the flow during the summer 

 months never falls below the capacity of these two pipes. 

 During the winter months the inflow is greatly reduced 

 as is obvious from the fact that, during the heat of a 

 summer day, the flow from the glacier is much greater 

 than at night. It is probable, therefore, that the average 

 flow throughout the year does not exceed 50 c. f . s. 



Taking the average flow from the glacier as 50 c. f. s., 

 the average amount of material carried in suspension by 

 the stream as 90 parts per million, the weight of the dry 

 silt as 75 lbs. per c. ft. and the area of the lake as 1,000,000 

 sq. yds., the average thickness of the annual layer, if 

 evenly distributed over the lake bottom, would be nearly 

 1 6 inch in thickness. This estimate is of course very 

 approximate ; it merely shows that the annual layer, if 

 evenly distributed, probably would not exceed 1/6 inch in 

 thickness. As the greater part of the sediment is 

 deposited near the upper end of the lake, the annual 

 layer is thickest near the upper end and thinnest at the 

 lower end. The lake is being gradually filled by deposi- 

 tion of the glacial silt, but the process is so slow that at 

 the present rate of sedimentation it will take over 1000 

 years to fill the basin; so that there is no danger of this 

 "Gein of the Canadian Bockies," as it is popularly called, 

 disappearing in the near future. 



5 Opus cit. p. 28. 



Am. Jour. Sci.— Fifth Series, Vol. IV, No. 23.— Xoyember, 19-3'2 

 25 



