175 



of the first chiss reiire.seut devcloiied resources; while those of the second 

 class repi-cseiit resources that are for the most part undeveloped. This 

 accounts for the difference in the atten.tion that each receives. The prob- 

 lem is not the prevention of floods Ijut the production of regular discharge 

 in our streams. The rainfall is irregular, and if it is allowed to run 

 off as it falls an irregular discliarge must result. Each drainage system 

 presents a different set of conditions that must l)e met in solving this 

 prolilem. The solution of the problem in northern Indiana is intimately 

 associated with the development of our lakes. 



'Ihis paper is limited to a discussion of some lakes of Kosciusko 

 County aiid tiieii' relation to the Tippecanoe drainage system of which they 

 foi'm a ]iari. 



'That I he Tiiiiie'iiiioe Kiver has a more regular flow than the 

 Waliasli is due to the fact that the Tipix'canoe has many more lakes and 

 swamps in its headwaters. (The closer pi'oximity of the Waliash to 

 bed-rock jirobalily has some intlueUve on the irregularity of its flow.) 



Some of the facts concerning the Wal)ash at and above Logansport. 

 and the Tippecanoe Kiver at and above Delphi are as follows: 



That is, the minimum discharge pei' square mile of drainage basin in 

 the Waliash is .IT. 7 i»er cent of that of a s(piare mile in tlii' Tippecanoe, 

 while the maximum ilischarg(> jier s(|uare mile of basin is is; per cent of 

 that of the Tippecanoe. This indicates I'oughly the value of lakes under 

 natural conditions. 



The most important factor in the ec(Hi(iniy of lakes is the treatment 

 of the outlet. This may be left in a natural condition, it may be dredged, 

 or it may lie dannued. I wish to describe the effect of these three con- 

 ditions on the drainage systems below the lake and upon the lake itself. 



A lake with a natural outlet usually imjiounds water early in the 

 year. With the first warm months their outlets liecome obstructed with 



