Report on the lands of the arid region of the United States, with a more detailed account of the lands of Utah

By G. K. Gilbert.

The field of my work in 1877 included so large a portion of the drainage basin of Great Salt Lake and so little else that it has proved most convenient to report on all of that basin, or rather on that part of it which lies within the Territory of Utah. In so doing, I have depended, for nearly all the lands draining to Utah Lake, upon the data gathered by Mr. Renshawe, of this survey, in connection with his topographic work. The remainder of the district, with very slight exception, I have myself visited.

The officials and citizens of the Territory have all freely contributed such information as I have sought, and have aided me in many ways; but I have been especially indebted to Mr. Martineau and Mr. Barton, the surveyors of Cache and Davis Counties; to Mr. Fox, the territorial surveyor; and to the Hon. A. P. Rockwood, the statistician of the Deseret Agricultural Society. Mr. Rockwood prepared a statistical report on the Territory in 1875, which has been of great service to me, and he has kindly placed at my disposal the manuscript details of his work as well as the published summary.

METHOD AND SCOPE OF INVESTIGATION.

Where agriculture is dependent upon irrigation, the extent of land that can be put to agricultural use is determined by the relation of the quantity of available water to the quantity of available land. There is a certain amount of water needed by a unit of land, and wherever the land susceptible of cultivation requires more water than is obtainable, only a portion of the land can be utilized. But there is also a limit to the amount of water that can be profitably employed on a unit of land, and where the supply of water is in excess of the quantity required by such lands as are properly disposed to receive and use it, only a portion of the water can be utilized. In order to ascertain, therefore, the extent of agricultural land in a given district, it is necessary to make a measurement of land, or a measurement of water, or perhaps both, and it is necessary to know the amount of water demanded by a unit area of the land under consideration.

The proper quota of water for irrigation depends on climate and soil and subsoil, as well as on the nature of the crop, and varies indefinitely under diverse conditions. As a rule, the best soils require least water; those which demand most are light sands on one hand and adhesive clays on the other. Where the subsoil is open and dry, more water is needed than where it is moist or impervious. Wherever there is an impervious substratum, the subsoil accumulates moisture and the demand for water diminishes from year to year. These and other considerations so complicate the subject that it is difficult to generalize, and I have found it more practicable to use in my investigations certain limiting quantities than to attempt in every case a diagnosis of the local conditions. By comparing the volumes of certain streams in Utah, that are now used in irrigation to their full capacity, with the quantities of land that they serve, I have found that one hundred acres of dry bench land (i. e., land with a deep, dry, open subsoil) will not yield a full crop of grain with less than one cubic foot of water per second, and this under the most favorable climate of the Territory. Where the climate is drier, a greater quantity is required. Where there is a moist subsoil, a less may suffice.

In the drier districts, where the streams are small, they are usually employed upon the dry benches, because these are most convenient to their sources; and it is very rarely the case that their utility is increased by the presence of a moist subsoil. But it is also in the drier districts that the extent of agricultural land is ascertained by the measurement of streams; and hence there is little danger of error if we use in all cases the criterion that applies to dry bench land. In the discussion of the lands of northern Utah, I have therefore assigned to each cubic foot per second of perennial flow the reclamation of one hundred acres of land, with the belief that the consequent estimates would never underrate, though they might sometimes exaggerate, the agricultural resources of the districts examined.

In the measurement of streams the following method was employed: A place was sought where the channel was straight for a distance equal to several times the width of the stream, and where for some distance there was little change in the dimensions of the cross section. Measurement was then made of the width (in feet), of the mean depth (in feet), and of the maximum surface current (in feet per second). The mean current was assumed to be four-fifths of the maximum current; and four-fifths of the product of the three measured elements was taken to give the flow in cubic feet per second. This method of measurement is confessedly crude, and is liable to considerable error, but with the time at my disposal no better was practicable, and its shortcomings are less to be regretted on account of the variability of the streams themselves.

All of the streams of Utah that flow from mountain slopes are subject to great fluctuations. They derive a large share of their water from the melting of snow, and not only does the melting vary as to its rapidity and season, but the quantity of snow to be melted varies greatly from year to year. A single measurement standing alone is quite inadequate to determine the capacity of a stream for irrigation, and as it was rarely practicable to visit a stream more than once, an endeavor was made to supplement the single determination by collating the judgments of residents as to the relative flow of the several creeks and rivers at other seasons and in other years. In districts where the water is nearly all used and its division and distribution are supervised by “watermasters”, those functionaries are able to afford information of a tolerably definite character, but in other districts it was necessary to make great allowance for errors of judgment. Certainly, that element of my estimates which is based on inquiries cannot claim so small a probability of error as the element based on measurements.

Streams that are formed in high mountains reach their highest stage in June, and their lowest in September or October. Streams from low mountains attain their maxima in April or May, and reach their low stages by August or September. In the low valleys the irrigation of wheat and other small grains begins about the first of June, and continues until the latter part of July. The irrigation of corn and potatoes begins in the early part of July, and continues until the middle of August. In the middle of July all of the land calls for water, and if the supply is sufficient at that time, it is sure to meet all demands at other times. It will be convenient to call that time the critical season. In the higher agricultural valleys corn and potatoes are not grown, but the irrigation of small grains and hay is carried on from the middle of June to the middle or latter part of August. Through all this time the volume of the streams is diminishing, and if they fail at all it is at the end of the season. The critical season for the higher valleys is about the middle of August.

In order to estimate properly the agricultural capability of a stream, it is necessary to ascertain its volume at its critical season. In the investigations of the past summer, this was accomplished by direct measurement in but a limited district. For the remainder of my field of operations I was compelled to depend on the estimates of others as to the relation between the volumes of streams at the time of measurement and at the critical season.

As will appear in the sequel, the uncertainty attaching to these determinations of volumes affects the grand total in but small degree. The utility of the large streams is not limited by their volumes so much as by the available land suitable for overflow, a quantity susceptible of more accurate determination, and the extent of land irrigable by the large streams is many times greater than that irrigable by the small.

No streams are used throughout the year, and few can be fully utilized during the spring flood. Wherever it is practicable to store up the surplus water until the time of need, the irrigable area is correspondingly increased. Enough has been accomplished in a few localities to demonstrate the feasibility of reclaiming thousands of acres by the aid of reservoirs, and eventually this will be done; but except in a small way it is not a work of the immediate future. For many years to come capital will find greater remuneration in taking possession of the large rivers.

In estimating the agricultural resources, it was, of course, necessary to take account of all future increase, and wherever storage by reservoirs seemed practicable a rough estimate was made of the extent of land that could be thus reclaimed.

There are a few restricted areas in Utah that yield remunerative crops to the farmer without the artificial application of water. Their productiveness is doubled or trebled by the use of water, and so far as they are susceptible of irrigation they need not be distinguished from the irrigable lands. When the greater rivers shall have been diverted to the work of irrigation, nearly all such areas will be supplied with water, but a few will not. The endeavor has been to include the latter as well as the former in the estimate of the agricultural land.

The term “agricultural land” is construed to include that which is used or may be used for the production of hay as well as that cultivated by the plow. Most irrigable lands may be utilized in either way, but there are some tracts which, on account of the severity of the climate or the impurity of the water, are adapted to the growth of grass only.

I have sought in the foregoing remarks to set forth as briefly as possible the methods and scope of my investigations, and to indicate the degree of accuracy to be anticipated in the resulting estimates. To these estimates we will now proceed.

IRRIGATION BY THE LARGE STREAMS.

Three rivers enter Great Salt Lake—the Bear, the Weber, and the Jordan, and upon their water will ultimately depend the major part of the agriculture of Utah. By a curious coincidence, the principal heads of the three rivers lie close together in the western end of the Uinta range of mountains.

The Bear River runs northward at first, and a little beyond the foot of the mountains enters the Territory of Wyoming. Swerving to the left, it passes again into Utah, and swerving again to the right returns to Wyoming. From Wyoming it runs northward into Idaho, and after making a great detour to the north returns on a more westerly line to Utah. It reënters in Cache Valley, and passes thence by a short cañon to its delta plain on the northwestern border of Great Salt Lake. Its principal tributaries are received in Idaho and in Cache Valley. Bordering upon the upper reaches of the river, there is little land available for cultivation, and the climate forbids any crop but hay. I am informed that the meadow land there somewhat exceeds two square miles in area. Where the river next enters Utah it runs for 30 miles through an open valley, the valley that contains the towns of Woodruff and Randolph. At the head it passes through a short defile, and can readily be thrown into two canals at such a level as to command the greater part of the valley, bringing about 90 square miles of land “under ditch”. For the irrigation of this amount the river is sufficient, but if the necessary water were thus appropriated, too little would remain for the use of the lands which border the contiguous portions of the river in Wyoming. These have equal claim to the use of the river, and a proper distribution of the water would assign it to the reclamation of the best selection of land in the two Territories. I estimate that such an adjustment would permit the Utah valley to irrigate 45 square miles with the water of the river. The minor streams of the valley will serve, in addition, 24 square miles. The climate is unfavorable to grain and the chief crop must be of hay.

Where the river next enters Utah it has acquired so great a volume that it is impracticable to make use of its entire amount. The portion of Cache Valley which lies in Utah can nearly all be irrigated. What is on the left bank of Bear River can be served by Logan River and other tributaries without calling on the main stream. The right bank will have to be served in connection with an adjacent tract in Idaho, and by a canal lying entirely in that Territory. The expense will be great, but not greater than the benefit will warrant. I estimate that the Utah division of Cache Valley will ultimately contain 250 square miles of irrigated land. The climate admits of the growth of wheat, oats, and corn, and such fruits as the apple, pear, and the apricot.

In leaving Cache Valley the river tumbles through a short, narrow cañon, and then enters the plain that borders the lake. The limestone walls of the cañon offer a secure foundation for the head works to a system of canals to supply the plain. Here, again, a large outlay is necessary, but the benefits will be more than commensurate. Not only will the entire alluvial plain of the Bear be served, but the valley of the Malade, as far as Oregon Springs, and the valley which extends from Little Mountain to Connor’s Spring. After deducting from these areas the land along the margin of the lake that is too saline to afford hope of reclamation, there remains a tract of 214 square miles. One-tenth of this is now in use, being in part watered by Box Elder Creek and other small creeks, and in part cultivated without irrigation.

In the following table are summed the agricultural resources of that portion of the Bear River drainage basin which lies in Utah:

The entire area of the Bear River District is about 3,620 square miles, 2¹⁄₂ per cent. being now under cultivation, and over 15 per cent. susceptible of cultivation.

The Weber River runs with a general northwesterly course from the Uinta Mountains to Great Salt Lake, entering the latter at the middle of its eastern shore. The Ogden is its only important tributary. At the foot of the mountains it enters Kamas Prairie, in which it can be made to irrigate a few square miles. Thence to Hennefer, a distance of 30 miles, it is continuously bordered by a strip of farming land about one-third of a mile broad. Then it passes a series of three close cañons—in the intervals of which are Round Valley, with a few acres of land, and Morgan Valley, with 7 square miles—and emerges upon its delta plain. Within this plain are no less than 219 square miles of farming land, of which about two-fifths are now in use. A part is unwatered, a part is watered by the Ogden River and by a number of creeks, and the remainder is watered by the Weber. To serve the higher portions of the plain a great outlay would be required, and I am of opinion that the highest levels cannot profitably be supplied. Still, a great extension of the irrigated area is inevitable, and I anticipate that when the water of the Weber has been carried as far as is economically practicable, not more than 15 miles of the plain will remain unsupplied. Deducting this amount, as well as the area served by the minor streams and springs of the plain, there remain 185 square miles dependent on the Weber and Ogden Rivers. The Ogden River has also to water 8 square miles in its upper course, and the Weber 34, making a total of 227 square miles dependent on the two streams. Whether they are competent to serve so great an area may well be questioned. On the 8th of October I found in the Ogden River, at the mouth of its cañon, a flow of 115 feet per second, and three days later the Weber showed 386 feet. There was almost no irrigation in progress at that time, and the total of 501 feet included practically all the water of the streams. To irrigate 227 square miles, the rivers need to furnish at the critical season (in this case about the 10th of July) 1,450 feet, or nearly three times their October volume. Of the ratio between their July and October volumes I have no direct means of judging, and the problem is too nice a one to be trusted to the estimates of residents unaided by measurements; but indirectly a partial judgment may be reached by comparing the rivers with certain tributaries of the Jordan which were twice observed. City Creek was measured on the 5th of July, and again on 1st of September, and Emigration and Parley creeks were measured July 5th, and again September 3rd. These streams rise in mountains that are about as high as those which furnish the Weber and its branches, and their conditions are generally parallel. Their measured volumes were as follows:

The comparison is not decisive, but it seems to show that the problem demands for its solution a careful examination at the “critical season.” If the Ogden and Weber had been measured in September, as were the other streams, their volumes would probably have been found less than in October; and this consideration appears to throw the balance of evidence against the competence of the rivers to water the contiguous lands.

But if their incompetence shall be proved, it does not follow that the lands must go dry. The Bear at the north and the Jordan at the south have each a great volume of surplus water, and either supply can be led without serious engineering difficulty to the lower levels of the delta of the Weber.

In the following table are summed the agricultural resources of the Weber drainage basin:

The estimate of 219 miles of cultivable land on the Delta Plain includes 15 miles that will probably never be irrigated, but may nevertheless be farmed.

The total area of the Weber basin (including the whole plain from Bonneville to Centerville, and excluding the main body of Kamas Prairie) is 2,450 square miles; 4³⁄₄ per cent. of the area is now under cultivation, and 10¹⁄₃ per cent. is susceptible of cultivation.

The Jordan River is the outlet of Utah Lake, and runs northward, entering Great Salt Lake at its southeastern angle. On the right it receives a number of large tributaries from the Wasatch Range. The largest tributary of Utah Lake is the Provo River, which rises in the Uinta Mountains close to the heads of the Weber and Bear.

From the mouth of its mountain cañon the Provo enters Kamas Prairie, and it hugs the south margin of the plain just as the Weber hugs the north margin, passing out by a narrow defile at the southwest corner. At one time in the history of the prairie the Provo flowed northward through it and joined itself to the Weber. The surface of the prairie was then lower than now, and the sand and gravel which the river brought from the mountains accumulated upon it. Eventually the Provo built its alluvium so high that its water found a new passage over the wall of the valley. The new channel, affording a more rapid descent than the old, quickened the current through the valley, and caused it to reverse its action and begin the excavation of the material it had deposited. So long as the river built up its bed, its channel was inconstant, shifting from place to place over the whole plain; but so soon as it began to cut away the bed, its position became fixed and the plain was abandoned. The river now flows in a narrow valley of its own making, 150 feet below the surface of the plain. As a result of this mode of origin, Kamas Prairie slopes uniformly from the Provo to the Weber, and it would be an immense undertaking to irrigate it with the water of the Weber. But the Provo River can be returned to its ancient duty with comparative ease. A few miles of canal will suffice to carry its water to the upper edge of the plain, and thence it can be led to every part. Already a small canal has been constructed and its enlargement may convert the whole prairie into a meadow. Thus the prairie, although part of the drainage basin of the Weber, belongs to the irrigation district of the Provo.

The Provo next follows a narrow rock bound valley for 7 miles, being skirted by bottom lands that admit of some farming. It then enters Provo Valley, an opening about as large as the last, and favored by a warm climate that permits the growth of breadstuffs. Thence to Utah Valley it follows a deep, close cañon.

The volume of the Provo is sufficient to water about 100 square miles. If it be permitted to serve 28 miles in Kamas Prairie and 40 miles in Provo Valley and its adjuncts, there will remain for Utah Valley the quota for 32 miles. The minor streams of the valley, American Fork, Spanish Fork, Hobble Creek, Payson Creek, etc., will irrigate 120 miles, making a total of 152 square miles supplied with water. The total land of the valley which might be irrigated if the water were sufficient amounts to no less than 225 miles.

Thus it appears that if all available lands on the upper Provo are reclaimed, one-third of Utah Valley must go unwatered, while if none of them are irrigated, nearly the whole of the valley will be supplied. A middle course would appear most wise, and will undoubtedly be followed. A gradual extension of the canals, as the demands and means of the communities dictate and permit, will bring lands successively into use in the order of their value and convenience, and when the limit is reached and title has been acquired to all the water, the most available lands in each of the three valleys traversed by the Provo will have been reclaimed. The residents of Kamas Prairie will probably have increased their meadows so as to furnish winter hay for herds sufficient to stock the summer pastures of the vicinity; Provo Valley, having a less favorable climate than Utah Valley, will have irrigated only its choicest soils; and the major part of the river will belong to Utah Valley. The apportionment may be roughly estimated as—Kamas Prairie, 10 miles; Provo Valley and Waldsburg, 20 miles, and Utah Valley, 70 miles.

Below Utah Lake there is little inequality of volume dependent on season. The lake is a natural reservoir 127 square miles in extent, and so far equalizes the outflow through the Jordan that the volume of that stream is less affected by the mean level of the lake than by the influence of northerly and southerly winds. With suitable head works its volume can be completely controlled, and, if desirable, the entire discharge of the lake can be concentrated in the season of irrigation.

The highest stage of the lake is in July, and the lowest in March or April; and the natural volume of its outlet has of course a corresponding change. In July I found that volume to be 1,275 feet per second, and I am informed by residents that the stream carried more than one-half as much water in its low stage; 1,000 feet is perhaps not far from the mean volume. When all possible use is made of Provo River and other tributaries the annual inflow of the lake will be diminished by about one-eighth, and the outflow by a greater fraction, which we will assume to be one-quarter. (This postulates that the evaporation is at the rate of 90 inches per year for the whole lake surface.) The remaining perennial outflow of 750 feet per second, if concentrated into four months, would irrigate for that period 350 square miles. It will be practicable to include under canals from the Jordan only about 160 square miles of farming land, and I think it safe to assume that the supply of water will be greatly in excess of the demand.

At the present time the Jordan is little used, the chief irrigation of Salt Lake Valley being performed by the large creeks that flow from the mountains at the east. It will not be long, however, before large canals are constructed to carry the Jordan water to all parts of the valley that lie below the level of Utah Lake. They will include 120 square miles of farming land.

The mountain streams, being no longer needed in the lower parts of the valley, will be carried to higher land and made to serve the benches at the base of the mountains. By these means the total agricultural area of the valley will be increased to 192 square miles. Eventually, the western canal will be carried about the north end of the Oquirrh range and made to irrigate the northern third of Tooele Valley. It will pass above the farming lands of E. T. City and Grantsville, and enable the streams which irrigate the latter town to be used upon the higher slopes. The service of the Jordan will amount to no less than 40 miles and the agricultural area of the valley will be increased to about 45 square miles.

Including Tooele Valley and Kamas Prairie with the drainage basin of the Jordan, its agricultural resources sum up as follows:

The drainage district has an area of 4,010 miles; 4¹⁄₂ per cent. are cultivated, and 11³⁄₄ per cent. may be cultivated.

It will be observed that in these estimates the available water above Utah Lake is regarded as insufficient for the available land, while below the lake there is a superabundance of water, and yet the lower stream is only a continuation of the upper streams. The difference arises from the function of the lake as a reservoir. Below the reservoir the whole of the annual supply can be controlled, but above it I have assumed that irrigation will merely make use for the irrigating season of the quantity which flows at the critical period. If artificial reservoirs can be constructed so as to store water for use in Utah Valley, a greater area can be cultivated. With adequate storage facilities the streams tributary to the lake can irrigate in Kamas Prairie 28 miles; in Provo Valley and vicinity 40 miles; in Thistle Valley 6 miles; on Salt Creek 16 miles, and in Utah Valley 225 miles, making a total of 315 miles; and there will still escape to the Jordan enough water to serve all the land assigned to that stream. If such storage is practicable, the estimate tabulated above should show 552 instead of 473 miles of cultivable land. The region most likely to afford storage facilities lies in the mountains where the waters rise. I did not visit it, and until it has been examined I shall not venture to increase the estimate.

The following table gives a summary for the Great Salt Lake river system:

This region includes an eighth part of the land area of the Territory, and more than one-half the agricultural land. It is the richest section of Utah. Nearly one-third of its available land is already in use. The cost of the canals by which its cultivated lands have been furnished with water has been about $2,000,000. To complete its system of irrigation will probably cost $5,000,000 more.

IRRIGATION BY SMALL STREAMS.

Through the remainder of the drainage basin of Great Salt Lake there are no large bodies of farming land. At wide intervals are small tracts, dependent on springs and small creeks, and the available land is in nearly every case greatly in excess of the available water. A few exceptional spots are cultivated without irrigation, but so far as they have been discovered they are so situated as to be moistened from beneath. No crops have been raised on dry bench lands.

The principal facts are gathered in the following table:

Nineteen tracts have not yet been surveyed by the land office.

The total area of the district is 13,370 square miles, of which one-tenth of one per cent. is cultivated, and one-fourth of one per cent. may be cultivated.

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.