230 American Fisheries Society. 



STREAMS IN DRAINED AREAS. 



As an example of the effect of drainage on lands lying 

 around the headwaters of streams mostly in cultivated areas, 

 usually in the prairie region, we may take the headwaters of 

 Root River in Mower County. Here much of the land is nearly 

 level and the stream itself was originally a succession of prairie 

 sloughs of considerable size connected by running streams over 

 gravel, all being fed by seepage from marshy springs. Con- 

 siderable areas of these sour, marshy lands have been drained, 

 resulting in such a reduced regular flow into the sloughs as to 

 admit of a highly increased water temperature, and such a re- 

 duction in flow that the former running sloughs are mere stag- 

 nant pools in midsummer and early fall. The incomplete drain- 

 age of these lands has produced results sufficient to clearly indi- 

 cate that with complete drainage of the area, now under 

 progress, the sloughs will be so reduced very shortly as to func- 

 tion merely as catch-basins during a considerable portion of the 

 year, destroying most of the aquatic life now present, and, as pre- 

 viously pointed out, reducing the flow of the entire stream for 

 miles below. This seems to be the case with hundreds of spring 

 or marsh-fed streams in the prairie region of the southern half 

 of the State, and it is only a question of time till drainage will 

 have absolutely annihilated the aquatic life over a vast area. 



However, about 50 per cent of the streams tributary to the 

 eastern half of the Root River are still maintaining themselves 

 by copious springs situated deep in forest-clad, abundantly 

 shaded ravines, and while the food supply usual to such streams 

 is becoming limited, still produce sufficient food to maintain ex- 

 cellent trout fishing throughout their upper waters, but usually 

 warming up to such an extent in the lower half, where Ihey ap- 

 proach the main valley, as to exclude trout from the waters there. 

 The abandonment of many water povv^er projects, most'y mills, in 

 the Root River and Whitewater basins, is directly traceable to 

 the great reduction in the permanent water supply of those 

 regions. 



STREAMS IN FORESTED AREAS SURROUNDED BY INTENSIVELY CULTI- 

 VATED LANDS. 



The Whitevv'ater valley in Olmsted and Winona counties, to 



