175 



uf the lirst class rei»i;esi'iit ilcNi'loiied resources; while those of the secuud 

 class reiuvsent resources tluit are for the most part undeveloped. This 

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

 lem is not the prevention of floods but 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 discharge must result. Each drainage system 

 iiresciits a difft'rent set of conditions that must he met in solving this 

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

 associated with the development of our lakes. 



'J lus ] taper is limited to a discussion of some lakes of Ko.sciusko 

 County and their i-elatioii to the Tippecanoe drainage system of which they 

 form a part. 



That the Tippecanoe River has a more retrular fiow than the 

 Wabash is due to the fact that the Tippecanoe has many more lakes and 

 swamps in its lieadwaters. (The closer proximity of the Wabash to 

 bed-rock probably has some intlueuv^e on the irregularity of its flow.) 



Some of the facts concerning the Wabash at and above Logansport. 

 and the Tiripecanoe River at and above Delphi are as follows: 



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

 the Wabash is .17.7 per cent of that of a s(iuare mile in the Tippecanoe, 

 while the maximum discharge per square mile of liasin is 18'! i)er cent of 

 that of the Tippecanoe. This indicates roughly the value of lakes under 

 natural conditions. 



The most important factor in the economy of lakes is the treatment 

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

 or it may l;e dammed. 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 inqiounds water early in the 

 vear. ^Vitll the first warm months their outlets become olistructed with 



