32 BULLETIN 211, U. S. DEPARTMENT OF AGRICULTURE. 
moisture and the soil, as well as for the maximum production of 
forage, and it should be brought about wherever possible. __ 
All arroyos should be gradually filled. This can not be done 
economically except very slowly and by letting the water do it. 
The cutting occurs because of the velocity of the water, which de- 
pends upon the quantity of water and the slope of the land. It is 
necessary to begin work at the heads of such channels, deflect the 
water from the main channels, and cause it to run over the more 
gently sloping land asasheet. Large obstructions across deep ditches 
or gullies are of little value unless they are so strong as to hold all the 
water which can collect behind them, as in a tank or lake. 
The same is, of course, true of the broader channels, where more 
extensive dams would be necessary. If such dams were built and 
should burst, much greater damage would be done, because of the 
large volume of water stored before the obstruction gave way. Small 
obstructions which allow a small quantity of soil to collect behind 
them upon which the grass may grow are of great advantage in chan- 
nels, provided most of the flood waters can be kept out of the channel 
by deflection at the head. 
All permanent lakes or tanks become local levels below which cut- 
ting can not occur in the drainage basin above them and are, of 
course, desirable. 
The general principle to be kept in mind is that the transporting 
power of water varies as the sixth power of its velocity. In other 
words, if the velocity of a stream be doubled, the weight of the largest 
particles it will push along is 64 times as great as that of the stream 
at the original velocity. But the velocity increases with the depth 
and with the gradient. The importance of inducing the water to 
flow slowly over the surface as a thin sheet is thus apparent. Anda 
relatively small amount of work properly applied will produce im- 
portant results in restoring to productivity land which is now only 
used to carry away water that should go into the ground. But none 
of this improvement work will be done until the worker knows he will 
be allowed to reap the benefit of his labor. 
Reseeding operations.—So far, experiments attempting to reseed 
artificially the ranges of most of New Mexico have resulted negatively. 
There are good reasons for this, to which we wish to call attention. 
There are, however, large areas where artificial reseeding will prove 
successful. Many high mountain valleys that receive considerable 
water, but have a short, cool season, can be set in timothy or redtop. _ 
Orchard grass, tall fescue, or brome-grass will grow in many localities 
if properly treated. Oats, barley, and wheat are already grown in 
many of the open parks of the higher mountain timbered lands, and 
much of the plains country of the eastern side of the State will grow 
-_ kafir, milo, or some of the other sorghums. Such lands are range lands 
