THE AMERICAN GEOLOGIST VOL. I. FEBRUARY, 1888. No. 2. THE NIOBRARA RIVER, CONSIDERED WITH REFERENCE TO ITS CAPACITY FOR IRRIGATION. BY DR. L. E. HICKS. The modern scientist is not a recluse. He has, indeed, his hours of seclusion, his days and weeks of patient labor in labo-. ratory or cabinet, but he does not bury himself there like the alchemist or astrologer of the middle ages. He walks abroad and is conversant with nature and with men, both in the gath-, ering of material for study and in the communication of the results of study. For it is the crowning glory of modern science that its results are not for the private gratification of the investigator, but for the benefit of mankind. Science is a teacher of men but also a servant of men. If, upon the one hand, it furnishes forth for the instruction of mankind crystal truths from deepest mines, eternal laws and principles from starry hights, on the other hand it helps to lift heavy burdens, helps to guide the farmer's plow, the carpenter's plane, the mariner's ship, lends a hand even for the most common drudgeries of life. A principle discovered is soon transmuted into a process for the production of wealth. All industrial progress is due to the application of scientific principles to the problems encountered in each line of effort. Geology, no less than other sciences, touches at many points the practical life of the millions. The problems of economic geology are numerous, and some of them are so far-reaching that a single one underlies the whole fabric of modern industries. The occurrence of iron ores, for instance, and the production from them of iron and steel, is a problem of economic geology, and it is so interwoven with all human industries that if the geologist should announce the speedy exhaustion of the supply of iron ore it would produce greater consternation than war or plague. Agriculture, the most ancient and the most important of all industries, is especially benefitted by the labors of the geologist. The very soil which the farmer cultivates depends for its fertility upon the rocks which have produced it by their disintegration. In arid regions the problem of water supply for domestic purposes, for power, and for irrigation, falls to the geologist for investigation. While THE AMERICAN GEOLOGIST will be for the most part devoted to pure science, yet it will not slight or ignore the problems of economic geology. An earnest of the disposition of its editors to do full justice to the claims of applied science may be found in the following discussion of the Niobrara river as an irrigation stream. Many other Nebraska rivers are well adapted for irrigation and I may perhaps report upon them in subsequent papers. Although such a discussion is primarily of greatest interest to citizens of the localities mentioned, it is not purely local. Irrigation has been practiced from the remotest ages. It is honorable on account of its antiquity, if for no other reason. Incidentally the geology of western Nebraska will be involved in the discussion; also the topography, the scenery, the general physical features and conditions of that region. These topics, it is hoped, will interest all readers however indifferent they may be to the practicability of irrigation. The early French voyageurs in North America had a quick eye for topographical features and striking natural phenomena of any kind. The names they conferred upon natural objects are often as significant as they are beautiful and appropriate. "La Belle riviere," the beautiful river, as they called the Ohio, is an example of their good taste and felicity of diction. So they called the Niobrara river "L'eau qui court," or Rapid river, from the swiftness of its current. It does indeed glide down its narrow bed with arrowy speed, stretching a silvery thread along the bottom of its valley as it descends from the high plateau of Wyoming, 5,000 feet above the level of the sea. Its mouth is about 1300 feet above tide, so that in the course of 300 miles it falls 3,700 feet, or 123 feet to the mile. This is the average slope, but in some places it descends much more rapidly. The upper portion of its valley is excavated in the loose friable strata of the newer Tertiary. It is accordingly a broad shallow trough with gentle slopes rising to the adjacent tablelands which are some 300 feet above the river. The serpentine course, the grassy slopes, and the clear swift water, all contribute to impart a peculiar charm to this region, in marked contrast to the rugged features of its lower course. In the vicinity of Valentine, in Cherry county, it is still flowing between walls of Tertiary age, but the rock is more compact and stands up in bold cliffs to the hight of 400 or 450 feet. The broad valley is reduced to a gorge or canon which continues to a point somewhat eastward of the 100th meridian, where the softer Cretaceous rocks yield more readily to aqueous and atmospheric erosion. From this point to its confluence with the Missouri river, the valley is of considerable breadth, and is bounded by moderate slopes. The Niobrara is an interesting stream throughout its whole course. For the first hundred miles from its mouth the geologist find the peculiar chalky rocks of the Cretaceous period, with their numerous and very interesting fossils. The Tertiary rocks along its middle and upper course contain the relics of a mammalian fauna unsurpassed in richness and variety. General Warren has stated that the Niobrara flows lengthwise upon the back of an anticlinal fold. This statement I have not personally verified, but, whether true or not, certainly enough is true of this river to make its exploration unusually fascinating to the geologist. The botanist finds in the valley of the Niobrara a flora quite unique for Nebraska. Great pines wave their branches where, according to any published map of the distribution of pines, none of them ought to be found. A remarkable eastward extension of the Rocky mountain pine (Pinus ponderosa) clothes the banks of the Niobrara and its tributaries with an evergreen fringe. The lover of the picturesque is delighted with the wild and varied scenery of the canons along the middle course of the Niobrara, as well as the broad green meadows above and the pretty islands below. A waterfall just below Fort Niobrara is worth taking a long journey to see. But the practical value of the Niobrara for irrigation is of greater consequence than its picturesque scenery. In determining this value the first question is whether the volume of water is sufficient to irrigate much land. On the 4th day of September, 1887, I measured it in the southern part of Dawes county with the following result: breadth, 21 ft., depth, 2 ft., velocity per second, 23 ft. The Niobrara at this point was therefore discharging 98 cubic feet of water in each second of time. This measurement was taken on its upper course and in one of the driest months of a dry year. Lower down, after it has received its large tributaries, the volume of water is far greater, but its use for irrigation is impracticable by reason of the high and steep banks. Just in proportion as the scenery becomes more picturesque, the utility of the stream becomes less. But in the counties Sioux, Box Butte, Dawes, Sheridan, and the western part of Cherry county, the valley is from one to five miles broad, and within it there is an abundance of good irrigable land. The rapid descent of this stream makes it possible to raise its waters to a considerable hight (relatively to its bed) by means of a ditch of no great length. Counting two feet per mile for the slope of the ditch, which is rather more than experience has shown to be necessary, we gain 10 feet per mile. Most of those beautiful stretches of land which the geologist calls terraces, while the farmer calls them second bottoms, and which offer the greatest facilities for irrigation, lie from fifteen to twenty-five feet above the stream. Along the Niobrara these could be watered from a ditch no more than two miles long on the average, since that would give an elevation of 20 feet.. How much land can be irrigated from a stream of the size of the upper Niobrara? If we knew just how many acres can be watered by a flow of one foot per second the answer would be But different soils, different sub-soils, and different crops make such vast differences in the conditions of the problem that its solution is by no means easy. Even when we take into consideration the differences of soils and crops we are hardly pre |