The contrast between the districts east and west of Great Salt Lake illustrates the combination of physical conditions essential to agriculture in our arid territories. An atmosphere endowed with but a small share of moisture precipitates freely only when it is reduced to a low temperature. Agriculture is dependent on the precipitation of moisture, but cannot endure the associated cold climate. It can flourish only where mountain masses turn over the aqueous product of their cold climates to low valleys endowed with genial climates. The Wasatch and Uinta crests stand from 6,000 to 9,000 feet higher than the valleys bordering Great Salt Lake. Their climate has a temperature from 20° to 30° lower. The snows that accumulate upon them in winter are not melted by the first warmth of spring, but yield slowly to the advancing sun, and all through the season of growing crops feed the streams that water the valleys. The Bear, the Weber, and the Jordan carry the moisture of the mountains to the warmth of the valleys, and fertility is the result.
To the north and west of the lake there are many mountains, but they are too low and small to store up snow banks until the time of need. Their streams are spent before the summer comes; and only a few springs are perennial. The result is a general desert, dotted by a few oases.
CHAPTER VIII.
IRRIGABLE LANDS OF THE VALLEY OF THE SEVIER RIVER.
By Captain C. E. Dutton.
As an agricultural region, the valley of the Sevier River and of its tributaries is one of the most important in Utah. The amount of arable land which may be reached by the waters of the stream is very much larger than the stream can water advantageously, and the time is probably not far distant when all the water that can be obtained will be utilized in producing cereals, and there is probably no other region in Utah where the various problems relating to the most economic use of water will be solved so speedily. It is, therefore, a region of unusual interest, regarded in the light of the new industrial problems which the irrigation of these western lands is now bringing forward. Fortunately, there is a smaller prospect of difficulty and obstruction in the settlement of the legal controversies which must inevitably arise elsewhere out of disputes about water rights than will be encountered in other regions, for the Mormon Church is an institution which quietly, yet resistlessly, assumes the power to settle such disputes, and the Mormon people in these outlying settlements yield to its assumptions an unhesitating obedience. Whatever the church deems best for the general welfare of its dependencies it dictates, and what it dictates is invariably done with promptitude, and none have yet been found to resist. This communal arrangement has been attended with great success so far as the development of the water resources are concerned, and the system of management has ordinarily been so conducted that the general welfare has been immensely benefited; and if individuals have suffered, it has not been made manifest by any apparent symptoms of general discontent or of individual resistance. The system is by no means perfect as yet, but its imperfections may be found in details which produce no present serious inconvenience, and they will no doubt be remedied as rapidly as they attain the magnitude of great evils.
The Sevier River has its course along the southeastern border of the Great Basin of the west, and its upper streams head in the lofty divide which separates the drainage system of the Colorado River on the south and east from the drainage system of the Great Basin on the north and west. The general course of the upper portion of the stream is from south to north, though its tributaries flow in many directions. The lower portion of the stream, within 60 miles of its end, suddenly breaks through one of the Basin Ranges on the west—the Pavant—and then turns southwestward and empties into Sevier Lake, one of the salinas of the Great Basin.
The main valley of the Sevier River has a N. S. trend, and begins on the divide referred to, about 270 miles almost due south of Great Salt Lake, and continues northward a distance of about 170 miles. There are three principal forks of this stream. The lowest fork is at Gunnison, 140 miles south of Salt Lake City, and called the San Pete, which waters a fine valley about 45 miles in length, and which is at present the most important agricultural district in Utah. About 80 miles farther up the stream, at Circle Valley, the river divides into two very nearly equal branches; one coming from the south, the other breaking through a great plateau on the east. These are called, respectively, the South and East Fork of the Sevier. The South Fork has its principal fountains far up on the surface of a great plateau—the Panguitch Plateau—whose broad expanse it drains by three considerable streams, which finally unite in the valley at the foot of its eastern slope.
The East Fork of the Sevier receives the waters of a beautiful valley lying to the eastward of and parallel to the main valley of the Sevier, and separated from it by a lofty plateau 90 miles in length from north to south, and from 10 to 20 miles in breadth, called the Sevier Plateau. Through this great barrier the stream has cut a wide gorge 4,000 feet in depth and 10 miles long, called East Fork Cañon, and right at its lower end it joins the South Fork of the Sevier.
The physical geography of the region drained by the waters of the river is highly interesting, and has an important relation to the subject. The area in question consists of a series of tabular blocks, of vast proportions, cut out of the general platform of the country by great faults, and lifted above it from 2,000 to nearly 6,000 feet, so that the absolute altitudes (above sea level) of the tables range from 9,000 to 11,500 feet. Where the valleys are lowest the tables are highest, and vice versa. The valleys or lowlands stand from 5,000 to 7,500 feet above the sea. The plateaus have areas ranging from 400 to 1,800 square miles, and collectively with the included lowlands within the drainage system of the Sevier have an area of about 5,400 square miles. The tables front the valleys with barriers which are more continuous and which more closely resemble long lines of cliffs than the mountain chains and sierras of other portions of the Rocky Mountain Region, and there are stretches of unbroken walls, crowned with vast precipices, 10, 20, and even 40 miles in length, which look down from snowy altitudes upon the broad and almost torrid expanses below. If the palisades of the Hudson had ten times their present altitude and five or six times their present length, and if they had been battered, notched, and crumbled by an unequal erosion, they would offer much the same appearance as that presented by the wall of the Sevier Plateau which fronts the main valley of the Sevier. If they were from six to eight times multiplied, and extended from Hoboken to West Point, and were similarly shattered, they would present the appearance of the eastern wall of Grass Valley. If they were eight to ten times multiplied, and imagined to extend around three-fourths of the periphery of an area 40 miles by 20, and but little damaged by erosion, they would represent the solemn battlements of the Aquarius Plateau. These great plateaus are masses of volcanic rock overlying sedimentaries, the latter so deeply buried that they are seldom seen even in the deepest chasms, while superposed floods of volcanic outflows are shown in sections, reaching sometimes a thickness of 5,000 feet. The dark colors of these rocks give a somber aspect to the scenery, and the gloomy fronts of the towering precipices are rendered peculiarly grand and imposing.