176 
PLAYA DE LOS PIMAS AS A WATER SOURCE. 
of the Copper Mine mountains. In its course southward, its valley bed widens, and travelling 
over the grits and sandstone, which are loose and porous, it sinks down and disappears. Its 
volume carried down and the point of sinking varies with the season, some summers higher up, 
and others lower down ; thus, at some seasons, the crossing at Cook’s trail is dry, and at others 
a running stream. 
The former was the case this summer, hut the water was found about six miles higher up, 
where it existed as a large collection of fresh standing water in pools or lagoons, surrounded 
by willow thickets. Four or six miles higher up still, it was a running stream, about 8 feet 
wide, and from 18 inches to 2| feet deep, travelling 2^ miles per hour. The valley of the river 
contained everywhere abundance of grass, with cotton-wood and walnut. 
As the river runs in a line of fault in the strata, if it he desired to obtain water in the river 
valley, at or below where Cook’s trail passes it, the river bottom and bed ought to he the spot 
selected for experiments. This is in a line running south 20° east from the magnetic meridian. 
Selecting such a line, and getting as close to the west side of a porphyry butte or hill would he 
the most likely method of tapping the river flowing beneath. A sinking to 12 or 15 feet near 
Cook’s trail, and less than 25 feet for ten miles down, would be the utmost depths required. 
From the volume of water which the Mimhres carries down, as well as from its uncertain 
presence at the trail crossings, it would appear necessary to take the river higher up (four miles 
above camp) and carry it down in a channel, and fill reservoirs or tanks constructed on the line 
of road. Basins of water, of great capacity, might thus beobtained; and by taking the river at 
this point, the supply would be constant the year round. The conveying channel might he an 
open sequia, hut the reservoirs would require to he covered. This stream, because small, is 
liable to he under estimated in its capability of supplying water. When crossed a few miles 
above the trail crossed upon this route, it has been found a constant stream by those who have 
crossed it. As such, Bartlett and Emory describe it, and as such it appeared when visited in 
the neighborhood of Ojo Caliente. When Major Emory crossed it, he describes it as 15 feet 
wide and 3 feet deep. Taking the lesser measurement, near Ojo Caliente, at 8 feet wide and 2 • 
feet deep, with a velocity of 2| miles per hour, there is a capacity for supplying water to fill a 
tank equal to 211,200 cubic feet per hour, or equal to a supply of 3,068,800 cubic feet in twenty- 
four hours. Thus, a single days’ supply would fill a large tank. 
Indeed, the Mimbres might he dammed higher up when the valley is narrow, and thus have a 
small lake formed, which could be constantly drawn upon, and form a reservoir, whence, by 
sequias, the wants of a railr-oad, several miles down, could be supplied. Sequias, though 
wasteful, are yet efficient for many miles. The town of Dona Ana, on the Rio Grrande, is sup¬ 
plied by sequias, which come off from the river ten miles above. 
The Ojo Caliente, described page 156, might also, if drawn upon, afford a large supply of pure 
water, palatable, though hard. 
Ojo de la Yacca, page 155. This spring exists in a depression in the general plain, which is 
most likely formed by a fault; in the angle of uptilted strata the water rises. The central 
spring is surrounded by rush and tule, is about fifteen feet across, and yields hut a small excess 
of water, which, owing to the depressed form of the basin, cannot overflow, and merely soaks 
the clay in the vicinity. As it does not flow, it does not admit of measurement; but as the re¬ 
moval of 200 gallons in twelve hours’ stay did not appear to affect the spring, perhaps 1,000 
gallons might be calculated on for every twenty-four hours as the surplus water of the spring. 
The Ojo de Inez was not visited ; it lies further up the canon than the water holes at Camp 
