Their dramatic achievements stand out boldly in this age of engineering triumphs. The mighty floods of western rivers have been checked behind enormous masonry dams, several of which are ranked among the highest in the world. Physical geography has been altered by transferring rivers from one drainage basin into that of another. Whole rivers are now flowing through tunnels that pierce lofty mountain ranges, and the water is being distributed in thousands of miles of canals to a million acres of desert. [Illustration: FIRST SETTLERS ON DESERT LANDS Settlers’ houses where once was the haunt of the buffalo] Owing to limitation of space only a few of these interesting irrigation projects of the United States Federal Government are here mentioned, although each is worthy of extended description. The annual reports of the Service are obtainable from the Superintendent of Public Documents in Washington, and these contain full details. In the order of their magnitude and the spectacular character of the engineering work, the Arrowrock dam in Idaho, Elephant Butte dam in New Mexico, Roosevelt dam in Arizona, Shoshone and Pathfinder dams in Wyoming, and Gunnison tunnel in Colorado, take first rank. Several of these are described at length elsewhere. [Illustration: AN OREGON MELON PATCH] _The Most Capacious Irrigation Reservoir_ In a region rich in thrilling reminiscence along the pathway trod by the Conquistadores of Spain, Federal engineers recently completed a monumental structure of masonry known as the Elephant Butte dam in New Mexico. This enormous mass of rock and cement effectually and permanently blocks the canyon of the Rio Grande just below the isolated basaltic peak from which it derives its name. It rises from the depths of the canyon 318 feet, and its crest length is 1674 feet. It owes its place among the greatest structures of the age to the enormous capacity of the reservoir created by it. Behind this towering monolith the greatest floods of the turbulent Rio Grande are held in a lake forty-five miles long and four miles wide. When full it will contain enough water to cover 2,627,700 acres to the depth of a foot, or sufficient to submerge the entire State of Connecticut ten inches deep. This stored water, when needed for irrigation, is turned back into the river and taken out at several points above and below El Paso, Texas; 180,000 acres in New Mexico, Texas and Old Mexico are being brought into cultivation. The charm of antiquity pervades the whole region. Here irrigation was practiced long before the first written word of our history. Centuries before the coming of the Spanish missionaries, a pastoral race dwelt here and cultivated this fertile valley along the stream. A later civilization merely absorbed and extended the primitive canals until the era of national reclamation aroused the valley to new life and purpose. While some of the primitive methods of agriculture, differing but slightly from those of Biblical days,