376 A NATIONAL PLAN FOR AMERICAN FORESTRY 



miles of the Buffalo River and some such land on tributary streams. 

 From the 170 gullies individually mapped had been removed 3,247,000 

 cubic yards of soil, or an average per gully of some 20,000 cubic 

 yards. Since on the average these gullies have been active for about 

 10 years, erosion is removing annually from this small area approxi- 

 mately 300,000 cubic yards of soil, or about 4,000 cubic yards per 

 square mile. With more than 100 square miles in the watershed under 

 cultivation, it is estimated that the average annual silt load of the 

 Buffalo River may total as much as a million cubic yards. 



On the adjoining Black River there is no large area where gullying 

 is so prevalent, but some gullies of enormous size have formed in the 

 deep and wide terrace, mostly concentrated in one locality of about 

 8 square miles. A single one of these gullies has, in about 15 years, 

 dumped directly into the Black River slightly more than a million 

 cubic yards of coarse and fine material. Examination of the drainage 

 revealed 31 active gullies. The volume of soil removed amounted 

 to some 3,850,000 cubic yards, or an average of about 125,000 cubic 

 yards per gully. 



Similar conditions exist on loess areas in various places along the 

 upper Mississippi Kiver, as in Calhoun and other counties in southern 

 Illinois. 



The fact that so much of the land in the silt loam uplands is being 

 eroded, that the eroded material is dumped so promptly into the 

 Mississippi, and that all run-off from this area is so closely related to 

 the floods in the lower river make this situation one of the really 

 critical national problems. Plans have been proposed for a gigantic 

 waterway system linking the Great Lakes with the Gulf. Because of 

 the excessive erosion now taking place, exceedingly costly dredging 

 would be necessary to construct and to maintain this channel. The 

 silt brought down by streams into the upper portion of the river is 

 creating difficulties for the present 9-foot navigation channel in the 

 upper part of the river. 



GULLYING OF BLUFFS 



In addition to sheet erosion and the deep gullying of terrace soils a 

 type of erosion independent of the character of cover occurs on the 

 uncultivated bluff area, induced solely by run-off from the cultivated 

 or pastured ground above. Such run-off is often diverted from natural 

 channels to some artificial channel over the bluff. Even though it 

 left the fields without picking up a heavy load of soil, it is capable 

 of causing immense destruction as it passes over the steep rocky 

 slopes, cutting away the loose residual soil mass, undermining and 

 uprooting trees, and eventually, in extreme cases, causing landslides. 

 Coarse detritus deposited by these streams in the valleys often ruins 

 tillable land, and the torrent of water often destroys roads, bridges, 

 and other improvements. 



MEASURES NEEDED FOR WATERSHED PROTECTION 



To prevent erosion on a private property in the upper Mississippi 

 River Basin is often beyond the power of the owner. Effective 

 control can be brought about only through the initiative and partici- 

 pation of governmental agencies. Great as is the local interest of 

 various public agencies, such as the States and counties in these 



