HYDROLOGY, TANKS AND WELLS. 
O nO 
w 
6 Montana Stat! 
■*Summerville 
.Mill co 
-no 
J £~Tonopah Well 
Seattle Well 
The precipitation both in winter and summer is greater on such 
mountains, and forested areas retard the run-off and permit the water 
to sink into the rocks. The flow is subject to 
seasonal changes, and during August and Sep- 
tember many springs are dry or greatly dimin- 
ished. Heavy rains also cause fluctuations. 
The water is cool, sometimes even cold, and is 
usually palatable, though a few of*the springs 
are slightly saline, and some contain other salts. 
From the direct dependence of the flow of 
the cold springs on seasonal rotation and on un- 
usually heavy rains it is evident that these 
springs are in greater part, at least, the vents 
of shallow circulating 1 waters. 
TANKS. 
Tanks are natural depressions in an impervi- 
ous stratum, in which rain or snow water col- 
lects and is preserved the greater portion of 
the year. In the area studied the principal 
formations upon which tanks occur are the 
playa clay and the more compact layers of the 
basalt. The water in tanks decreases in vol- 
ume and becomes poorer in quality as summer 
progresses; by August some are dry, and the 
water of others is scarcely drinkable. 
WELLS. 
Wells have been sunk at a number of places 
in the gravels of either the flats or the gulches. 
Wells sunk in gulches where there are signs 
8 Rose's Well 
a 
;; Miller No.l 
of water have almost without exception proved 
successful ; wells in the flats have been almost 
as uniformly successful. In the inclosed val- 
leys the water table near the mountains, where 
the desert gravels are very permeable to water, 
seems to lie at considerable depths below the 
surface, but at the play as the tw T o planes ap- 
proach each other. In Death Valley water 
stands upon the surface, while in Sarcobatus 
Flat the water table is but 2 feet below the sur- 
face (fig. 2). In other flats the depth is con- 
siderably greater, but by analogy wells located 
near playas should encounter water at less 
depths than those on alluvial slopes. The supply seems sufficient for 
stock, but insufficient for extensive irrigation. 
-Mud Spring 
Amargosa Mine 
(Dry) 
Miller No.2 
