662 



CONSERVATION 



and wholly beyond human control ; but 

 with advancing conquest of the earth's 

 surface, the mystery of rivers has been 

 cleared away, and their origin and 

 growth no less than their uses are com- 

 ing within everyday knowledge. To- 

 day the commercial and industrial val- 

 ues of our running waters can be ap- 

 praised and controlled about as defi- 

 nitely as those of our lands. 



In a state of nature the slopes of 

 the land, the texture of the soil, and 

 the vegetable cover are brought into 

 adjustment during ages in such man- 

 ner that most streams flow fairly clear, 

 and in fairly uniform volume through- 

 out the year — there is a general equilib- 

 rium or balance extending all the way 

 from the hillsides on which the storm- 

 waters gather to the coast where the 

 flow returns to the sea. When the rain 

 falls on a forest the beating drops are 

 broken into spray which soaks gently 

 into the mulch or trickles down the 

 trunk and roots into the earth ; the 

 moisture seldom collects in gully- 

 making rills, but forms a ground- 

 water which soaks deeply, to finally re- 

 appear as clear springs or seepage in 

 the banks and beds of the spring 

 branches. Over prairies the sward in 

 time grows so tough as to resist the 

 beating of the storm, while the grass 

 helps to retain the moisture and reduce 

 run-off, with attendant gullying; yet 

 in a state of nature the slopes of prairie- 

 lands are always gentler and flatter 

 than those of woodlands, in which the 

 surface is better protected from the 

 elements. In both types of surface 

 (and in all intermediate types) the final 

 or optimum condition toward which 

 all the agencies tend is one in which 

 nearly all of the precipitation soaks 

 into the earth to form a ground-water, 

 leaving little run-oflF on the surface ; 

 in which condition springs abound, 

 floods seldom reach great heights, and 

 the streams are seldom dry or even low 

 in summer or between storms. In this 

 condition there is little soil erosion, and 

 comparatively little scouring of beds, 

 building of bars, or shifting of chan- 

 nels in the lower reaches of the rivers. 

 Judging from the best geological data 



available, the annual soil-wash from 

 the 400,000 square miles of what may 

 now be called the Appalachian states 

 was less than 75,000,000 tons, perhaps 

 less than 50,000,000 tons annually ; 

 while the range from high to low water 

 in the mill streams, and even in such 

 rivers as the Tennessee, Cumberland, 

 Alabama, and Savannah, was not such 

 as to interfere seriously with control 

 for power in the upper reaches or with 

 navigation in the lower reaches. 



The efifect of settlement throughout 

 this region has been, as elsewhere, to 

 distribute the natural equilibrium or 

 balance, whereby both the soil and its 

 cover and the running waters are con- 

 trolled. It is everyday knowledge that 

 springs have failed in thousands ; that 

 spring branches have run dry ; that it 

 has become necessary to deepen wells ; 

 that brooks once clear and fairly uni- 

 form throughout the year now run 

 muddy when they run at all, and range 

 from destructive torrents after storms 

 to trifling rivulets during droughts ; 

 and that the utility of the upper reaches 

 for power and the lower reaches for 

 navigation has been greatly reduced. 

 The reason is now a commonplace of 

 daily knowledge : The leading factor 

 is deforestation of the uplands, where- 

 by the surface is exposed to the ele- 

 ments, and the storm waters gather in 

 torrents, cutting gullies, flooding bot- 

 toms, carrying debris over the low- 

 lands, and choking the channels even 

 of the larger rivers. Next in gravity 

 is thoughtless farming, so conducted as 

 to expose a thin layer of friable soil 

 to storms, whereby the fields are gul- 

 lied and impoverished, and the richest 

 and most soluble portions of the soil 

 are swept away — to accumulate in the 

 lower reaches and either bar navigation 

 or compel expensive dredging to main- 

 tain it. The change from the natural 

 condition cannot be measured without 

 extensive observations and surveys ; 

 yet any one familiar with the region 

 and observant of the changes of the 

 past quarter century must estimate that 

 the annual soil-waste is at least doubled 

 and that the range from freshet stage 

 to low water is increased from fifty to 



