RANGE WATERING PLACES IN THE SOUTHWEST 33 
important palatable plants, as a silt and erosion-control measure 
and as insurance against the severe effects of overgrazing during 
dry periods. During drought years it will be necessary to cull the 
herds heavily and dispose of the surplus animals early. The chances 
for success in revegetating overgrazed southwestern ranges by arti- 
ficial seeding with introduced species are so hmited that it is neces- 
sary to place most dependence on proper care and development of the 
vegetation native to the region. 
INCLOSURES ABOVE RESERVOIRS ESPECIALLY VALUABLE IF PROPERLY GRAZED 
Concentration of stock at water and in drainage troughs with con- 
verging of stock trails, causing gullies, can not ‘be avoided entirely. 
The damage to vegetation from unavoidable concentration will be 
lessened if the range immediately above the storage basin is not 
overgrazed. Silting i is decidedly reduced by a good stand of vegeta- 
tion in the channels. The velocity of moderate volumes of muddy 
storm water is decreased, considerable silt is caught in the grass, 
eddies around shrubs cause many small deposits, ‘and the water is 
clearer when it reaches the reservoir. Gully washing is retarded and 
sometimes prevented, and gullies may even be reclaimed. For these 
reasons a fenced inclosure in which grazing can be rigidly regulated 
will be of great benefit in improving and maintaining satisfactory 
vegetation in the channels of dry washes or little valleys above many 
reservoirs. (Pl. XVI, fig. 2.) It is of especial importance to allow 
the vegetation in such a “pasture to attain a vigorous and substan- 
tial erowth each season before it is grazed, and overgrazing and 
excessive trampling should never take place. The length of such 
an inclosure from the water to the upper fence is of more importance 
than the area. Such rigidly regulated areas, 200 or 300 acres in size 
and one-half to three-fourths mile long have given highly satis- 
factory results. For the fullest benefits the pasture should be fenced 
before the sodded channel begins to erode. 
The entire cost of such a pasture is not a proper charge against the 
cost of the water development, since it can often be of aid in the 
handling of stock and can usually be grazed under proper regulation 
without the loss of much forage and without affecting the “mainte- 
nance of good vegetation in the channel. It is not considered prac- 
ticable to have pastures above all reservoirs. The use of such in- 
closures primarily for reduction of silting is limited by the expense, 
by the blocking of free movement of stock over the remainder of the 
range, and by “their small value in valleys of large size with badly 
eroded channels. Advantage can sometimes be taken of existing 
pastures by locating new reservoirs along their lower fences. 
Lf it is essential to have corrals or other facilities for handling 
livestock at the water they should be located below the dam. This 
will help in preventing excessive trampling above the dam and the 
washing of much dust and other débris into the storage basin. 
DEGi:RABILITY OF SPILLWAY NEAR UPPER END OF RESERVOIR 
Flood waters usually carry considerable silt. If the spillway is 
hear the upper end of the body of water the silt deposited in the 
