no 



FORESTRY AND IRRIGATION. 



March, 



rents change to quieter streams. Here 

 boulders are left during one freshet in 

 bars, guiding the current, until a greater 

 freshet moves them or forms a new chan- 

 nel around them. Here eddies collect 

 silt and form fertile farm land that ma}- 

 either be swept awa}' the next year or 

 remain during many years of profitable 

 cultivation. In addition to the move- 

 ment and lodgment of earth and stone, 

 driftwood has caused even more dam- 



WRECK OF A RAILROAD BRIDGE, DOE RIVER, TENN 



age, especially to bridges, mo.st of which 

 would have staid had not floating forest 

 debris, logs, buildings, and other bridges 

 lodged against them and pushed them 

 over or formed dams to spread the flood. 

 The debris from the forest is com- 

 posed largely of branch wood, logs, and 

 uprooted trees left along banks and bars 

 by former freshets ; but in this flood 

 were also many culled logs, fresh from 

 stump land, valuable logs from broken 

 booms, and a verj' large number of 

 freshly uprooted trees, torn from river unusually 



banks and from wooded islands, or- 

 chards, and flats. A large portion of 

 other debris con.sisted of fence rails, 

 slabs, edgings, and lumber from saw- 

 mills ; wreckage from barns, outhouses, 

 houses, stores, mills, and bridges, among 

 which there was much furniture and 

 machinery. 



The amount of damage is very difficult 

 to estimate, owing to its variety and the 

 far-reaching effect of the changes made. 

 Besides the usual items of loss, 

 such as human lives, domestic 

 animals, buildings, mills, logs 

 and lumber, bridges, railroads, 

 wagon roads, and growing crops, 

 agricultural and other lands were 

 washed away or gullied, de- 

 prived of humus, or covered 

 with sand or other debris. The 

 streets of towns and villages were 

 covered with slime, and wells 

 have been filled with polluted 

 water. The flood was followed 

 by epidemics of fever and dys- 

 entery'. Stagnation of business 

 and the discouragement of enter- 

 prise was caused through lack of 

 transportation. 



Several of the counties of 

 eastern Tennessee suffered a di- 

 rect loss of over $1 ,000,000 each. 

 Four railroads in Carter and 

 Washington counties lost $300,- 

 000 by damage to tracks, bridges, 

 and buildings. 



Why so much damage? 

 There has been much careless- 

 ness in placing buildings , bridges , 

 roads, and railroads in exposed 

 situations, and few people have 

 considered the increased liabil- 

 ity to floods through the effect 

 of fire, grazing, and clearing 

 upon the forests that once covered the 

 mountain sides. 



Rain must fall before it can run off, 

 but the rapidity of the run-off may be 

 greatly modified. How much was the 

 run-off modified in this case? Before 

 the flood the streams were full and the 

 ground was thoroughly saturated ; they 

 could hold no more water ; then the 

 heavy rain came, during which 8 8 

 inches of water fell in 12 hours. The 

 amount of water to be disposed of was 



great. 



In this region there 



