| Districts. | Square miles cultivated during 1877. | Acres cultivated during 1877. | Square miles of irrigable land. | Acres irrigable land. |
|---|---|---|---|---|
| San Pete Valley | 17 | 11,000 | 31.2 | 20,000 |
| Gunnison | 4.4 | 2,800 | 6.2 | 4,000 |
| Sevier Valley above Gunnison | 16.5 | 10,500 | 54.7 | 35,000 |
| Circle Valley | 1.2 | 750 | 6.3 | 4,000 |
| Panguitch and above | 2.8 | 1,800 | 11 | 7,000 |
| Total | 41.9 | 26,850 | 109.4 | 70,000 |
Nevertheless, I am persuaded that it will be practicable to extend the possibility of irrigation by an increase of water supply to a degree sufficient to irrigate every acre of the main valley of the Sevier which can be reached by canals, and which is also fit for cultivation. It is by the method of artificial reservoirs. There is probably no region in the world more admirably suited to the easy, cheap, and efficient application of this method than this very region drained by the Sevier River. The sources of this river are found at high altitudes, but these high places are not mountains in the ordinary sense, but great plateaus with broad summits. These table tops have vast numbers of large basins broad enough for great ponds, which are now drained by narrow gorges cut through volcanic sheets and leading down to lower levels. These gorges are in most cases narrow cañons, which, being once barred across, will dam the waters above them. I could not select a better example than the following: About 15 miles southwest of the town of Panguitch is a broad basin, the central part of which is occupied by a shallow lake, about 1¹⁄₄ miles long and nearly a mile wide, called Panguitch Lake. Its altitude is about 8,200 feet. It is completely surrounded with barriers, nowhere less than 100 feet in height, and finds its drainage through a narrow cleft on the northeast side. It receives the influx of two fine streams, which in May and June must carry heavy floods of water from the lofty rim and broad watershed of the Panguitch Plateau lying to the westward. Even in August their united flow must reach 50 feet per second. By throwing a dam 30 feet high and 50 or 60 feet long across the outlet between its walls of solid trachyte, a lake would be formed with an area of 6 or 7 square miles. There are many such basins upon the Panguitch Plateau, and it would be a low estimate to say that it would be possible, at comparatively small expense, to create 30 or 40 square miles of lake surface, with an average depth of 20 feet, upon that plateau alone. The precipitation upon its surface would be more than sufficient to fill these lakes every year. A dam across the upper part of East Fork Cañon would create a lake behind it which might have an area of 12 to 15 square miles. Numerous reservoirs could be created at small expense in Grass Valley, upon the Fish Lake Plateau, and upon the Sevier Plateau, and in those valleys which are drained by Salina Creek and its tributaries. The Sevier River itself can be cheaply dammed at several gorges and made to overflow swampy flats above—notably at the head of Marysvale Cañon, and again just north of Van Buren’s ranch. Other things equal, it would be better, as well as cheaper, to build dams at higher levels, since the evaporation is much less there than in the valleys, and the natural facilities for creating lakes are also greater.
In this way, I believe it to be practicable to reserve a store of water sufficient to irrigate every acre of ground in the Sevier Valley, which is by the nature of its soil and its situation suitable for irrigation. It may be noted, too, that the “tank system” thus suggested would not interfere with or take the place of the present system, but would be supplementary to it. The streams would in June and early July run through the lakes and over the dams, yielding about as much water as they now yield in those months, and the reservoirs would not have to be drawn upon before the middle of July.
A very interesting subject connected with the peculiar conditions of agriculture in the west is the origin and distribution of alkaline salts in the soil. In moist regions such occurrences are rare. They are peculiar to arid regions, and, in truth, very few arid regions fail to exhibit them. The cause in a general way is well known. The small amount of rain which falls during the wet season penetrates deeply into the earth, where it gradually takes up such soluble salts as it encounters there. During the dry season which follows, there is always going on an evaporation from the surface, however dry it may appear to the senses. It is a mistake to suppose that because the saline soil is as dry as ashes no evaporation is in progress. In many cases this may be true; but often in the most arid regions there are many localities where the water collects far below the immediate surface. By capillary action, this water always tends to diffuse itself throughout the loose materials which make up the overlying soils. As fast as it is evaporated at the surface, more water from below rises by capillary action to take its place. When the air is exceedingly dry, as it invariably is in summer throughout the whole Rocky Mountain Region at moderate altitudes, the evaporative power becomes so great and extends to such a depth below the immediate surface, that we are unable to recognize the slightest traces of moisture indicating that evaporation is going on. The water which may have accumulated beneath has gradually risen by percolation through the interstices of the unconsolidated materials of the soil, bringing with it whatever soluble salts it may have taken into solution during its sojourn beneath the surface. These soluble salts are left at the surface by the final evaporation of the water, and, as the process is continuous until the reservoir beneath is exhausted, the salts accumulate. Contrast this now with the action going on in a moist country. Here the copious waters wash the soils as rapidly as the salts come up from below, and carry them in solution into the drainage channels. During the greater part of the year the movement of the waters is partly from the surface downward into the subterranean water courses, from which they emerge in springs; partly by surface drainages into rills, and thence into living streams. By both movements, any tendency to accumulate soluble salts at the surface during the relatively brief periods of dryness is prevented. In a dry country the periods of dryness are very much longer, and the rainfall is seldom sufficient to wash the accumulated salts from the soil. There is, however, usually a limit to this accumulation, since at long intervals rains occur sufficient to remove a large portion of the salts. The difference between a dry and wet country in this respect is therefore one of degree rather than of kind. In a dry country the periods of accumulation of salts at the surface are long and continuous, while the washings of the soil are rare and imperfect. In a wet country the periods of accumulation are short and rare, while the washings are frequent, copious, and thorough.
The saline materials vary widely in character and constitution. They are, however, chiefly salts of soda, lime, potash, and magnesia. Sometimes they exist in the condition of chlorides, sometimes of carbonates, and sometimes of sulphates. The reactions from which they are derived are many, and it will be proper here to give only a few illustrations. A portion of the salts of magnesia and soda are derived from the decomposition, by atmospheric influences, of volcanic, granitic, and other crystalline rocks. Where these materials exist in the form of felspar, hornblende, and pyroxene, the great decomposing agent is water charged with the carbonic acid of the atmosphere, by the action of which soda, magnesia, and lime are, with inconceivable slowness, dissolved out of the constituents of these rocks. There is no stream, however pure it may apparently be, which does not carry more or less of chlorides and carbonates in solution. The sulphates are derived mainly from subterranean sources. In the Rocky Mountain Region, one of the most common forms of sulphate is found very abundantly in the rocks of the Carboniferous, Triassic, Cretaceous, and Tertiary Ages, in the forms of gypsum and selenite, which are sulphates of lime. Whenever waters containing carbonate of soda are filtered through strata containing these sulphates, a double decomposition takes place, by which carbonate of lime and sulphate of soda are formed. The carbonate of lime is very slightly soluble in water, while the sulphate of soda is highly so, and it is well known that waters emanating from the sedimentary rocks just spoken of are very frequently highly charged with it. Such, doubtless, is the origin of this mineral in the so called alkaline waters of the west, and of all the soluble minerals which pass under the name of alkali it is one of the most common. Carbonate of soda is also abundant in the soils. It is frequently found in the summer time, coating the surface of bottom lands which earlier in the season have been submerged by the augmented streams. Common salt (chloride of sodium) is even more abundant than the sulphate. It is well known, however, that many of the sedimentary rocks, particularly those of the Triassic and Jurassic Age, contain an abundance of it, and there are many localities in the west where a very fair article of common salt is obtained by the lixiviation of the detritus of the red Triassic rocks. Incrustations of these soluble saline materials occur most abundantly in the vicinity of the rivers and in the bottom lands. This may at first seem somewhat strange, but it is susceptible of a ready explanation. In order that these salts may accumulate at the surface, there must be going on continually a slow transmission of moisture from under ground upward, and since a continuous supply of water is more frequently found in the bottom lands than elsewhere, it follows that the conditions of these accumulations are here more frequently fulfilled. They may, however, and do occur at localities which probably contain subterranean reservoirs of water, which are annually filled during the wet season. Sometimes these salts are so abundant that the land requires a thorough washing before it is fit for agriculture, and the Mormons have on several occasions, when founding settlements, been obliged to allow the waters from their ditches to leach the land for many months, and in one or two cases for two, and even three, years, before a good crop could be raised. There is no difficulty, however, in removing any quantity of these readily soluble salts from the soil, provided this leaching process be continued long enough; and it is usually found that lands which were originally highly akaline become, when reclaimed from their alkalinity, among the most fertile.
There yet remains for mention a number of small areas served by some minor streams in southwestern Utah. These little creeks head in the mountains, but are soon lost in the deserts of that arid and torrid region, none of their waters finding their way to the ocean. The greater number of them belong to the drainage basin of Sevier Lake. In each case the water supply is small, and inadequate to supply the available land. In nearly every case the competence of the supply has been determined in the most practical way—by the operations of settlers; but some allowance has been made for an increase of the irrigable land by the more economic use of the water. This can be accomplished by the construction of better waterways, and by more carefully flowing the water over the lands.
The following table exhibits the extent of these areas:
| Districts. | Square miles. | Acres. |
|---|---|---|
| Cherry Creek | .2 | 100 |
| Judd Creek | .2 | 100 |
| Levan | 3.1 | 2,000 |
| Scipio | 2.6 | 1,700 |
| Holden | 1.6 | 1,000 |
| Fillmore and Oak Creek | 5.5 | 3,500 |
| Meadow Creek | 1.9 | 1,200 |
| Kanosh | 3.1 | 2,000 |
| Beaver Creek and tributaries | 21.9 | 14,000 |
| Paragoonah | 1.5 | 1,000 |
| Parowan | 1.5 | 1,000 |
| Summit | .6 | 400 |
| Cedar City, Iron City, and Fort Hamilton | 3.6 | 2,300 |
| Mountain Meadows | .3 | 200 |
| Pinto | .3 | 200 |
| Hebron | 1.6 | 1,000 |
| Total | 49.5 | 31,700 |