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Show i SURVEYS IX COLORADO RIVER RASIN" One of the largest and most hazardous haz-ardous project undertaken by trie! department of the interior, through the Geographical survey lias been that of mapping Colorado river' and its tributaries. From time to time since 1SG9, when Maj. J. W. Powell, afterward director of the Geological survey, first explored the Grand' canyon of the Colorado, topograph- ers, engineers, and geologists of thej survey have been making surveys in parts of the 244.000 square miles drained by the river. Systematic surveys sur-veys for a series of large-scale maps of the river and. the adjacent areas were begun in 1909. and the field work required for these maps Is now practically completed. Much of thisj field work was hazardous and the surveying parties at times suffered treat hardships. ' When Major Powell made his first historic trip west stretches of the basin of the Colorado were still uu-j explored, and the great canyon itself j was practically unknown except as t theme for fantastic tales by the Indians. In-dians. Today the maps prepared and, j the information collected by the Geo logical survey furnish an accurate' knowledge of nearly 2,000 miles of I the watercourses in this basin,, showing show-ing every turn of every stream, the location and the fall of all the rapids, rap-ids, the topography and geology of the canyon walls, and the location and cross sections of the more feasible feas-ible dam sites. Some of these maps have been included in-cluded in books; others are published pub-lished separately, in sets. The Geological Geo-logical survey's water supply paper 369, "profile surveys in the Colorado River basin in Wyoming, Utah, Colorado Col-orado and New Mexico," contains 43 maps showing plans and profiles of the Colorado above Green river, of Green River and its tributaries, and of a part of Gila river. The more recent re-cent maps are printed in three colors, col-ors, black, blue and brown, used respectively res-pectively for the geographic names, the rivers, and the levels in the region, re-gion, and represent the highest type of river survey maps. The following maps have already been published; Green River from Green River, Utah, Ut-ah, to Green River, Wyoming, comprising com-prising 16 sheets; Colorado River from Lees Ferry, Arizona to mouth of Greenriver Utah, and San Juan River to Chinle Creek, Utah, comprising com-prising 22 sheets. Other maps now in press or in co;urse of preparation are; Yampa River from Green River to Morgan Gulch, Colo., 5 sheets; Colorado River from Lees Ferry Arizona Ari-zona to Black Canyon, Arizona, Nev. and Virgin River, 21- sheets; Colorado Colo-rado River from Black Canyon to the Mexican boundary. These maps are sold for 10 cents each. The preparation of these maps constitutes one part of the work done by the Geological survey in determining de-termining the water resources of the United; States and in classifiying the public lands. It is part of a systematic syste-matic program for obtaining the basic ba-sic data essential to1 a comprehensive comprehen-sive national scheme for the development develop-ment of rivers for power, irrigation, and other uses. Another part of the work is that of gaging the streams to determine their flow. On Colorado river such stream gaging has been in progress since 1S9 5, and 77 gaging stations are now regularly maintained in us basin. The measurements that made are published annually in the Geological Geolo-gical survey's series of reports on surface water supply. The maps and the records of stream flow are from time to time supplemented by other publications. A paper entitled "Colorado "Col-orado River and its Utilization," published some time ago as Water SunDlv Paner 395 can still be obtain ed, and three other reports are now in preparation that will show how much water is available in the basin and will contain suggestions as to its best use. i |