THE LIFE OF DEVILS F.AKE 17 



seepay:e. During the sumraor of 1916 in spite of an estimated 

 daily flow of 13,249 cu. ni. ■ from the Mauvaise Coulee, the lake 

 fell about 0.24 m. from May 1 to November 5. 



The future of Devils Lake can only be read in the record of 

 the past. With present climatic conditions continuing it will prob- 

 ably disappear during the next forty or fifty years. The annual 

 drop is apt to increase with decrease in depth. "From him that 

 hath not shall l)e taken away even that which he hath" is ap- 

 plicable to lakes as well as to men. The eastern section of Devils 

 Lake, which was separated from the main body in 1903 by a high- 

 way at the Narrows, and which in 1913 had an average depth of 

 1.8 to 2.4 m. was more than 0.9 m. lower than the latter in 1922, 

 and is now (1923) little more than a mud flat, covered in places 

 with a few centimetres of water, while Minnewaukan Bay, which 

 in 1916 contained 0.9 to 1.2 m. of Avater (plate 10) virtually dis- 

 appeared in 1917, while the main body fell only 0.4 m. 



Whether climatic cycles may ensue to raise the lake to its for- 

 mer high estate must be left to the future to decide. Such changes, 

 however, are reckoned in centuries, not years. The immediate 

 prospect is one of continued and increasing fall and ultimate dry- 

 ness, the fate of so many other glacial lakes in North America. The 

 youth and maturity of Devils Lake are past, the period of old age 

 has arrived. 



MAIN LAKE, PHYSIOGEAPHY 



As may be seen from the map (fig. 2) Devils Lake has the 

 form of a long, narrow body with several arms at right angles to 

 the latter. These arms or bays probably mark the course of tribu- 

 taries of the old pre-glacial river in whose valley the lake now lies 

 The area of Devils Lake in 1883 was approximately 401.5 square 

 km. with a shore line over 290 km. long. Today the area probably 

 does not exceed 180-200 km. and the shore line has also been consid- 

 erably reduced, tho not to the same extent as the former. 



The recession of Devils Lake, together with the construction of 

 highway embankments at various points across the lake, has resulted 

 in the development of several smaller lakes, besides the separation of 

 the glacial lake Minnewaukan into the present Devils and Stump 

 Lakes. Some of these smaller parts, which are spring fed, have re- 

 tained their freshness; while others have a high concentration of 

 salts, the proportions of which vary of course in each individual 

 ease. At present Devils Lake proper is divided into four chief 

 parts — Minnewaukan Bay*, Main, East and Lamoreau Lakes ; the 

 principal of which, and that on which most of the data in this 

 treatise are based, is Main Lake. This is an irregular sheet of 



•Aug. 15. 



♦Virtually dry — 1924. 



