Meanwhile private enterprises are reclaiming extensive tracts in Klickitat county, and in fact nearly all the counties bordering on the Columbia and Snake rivers in eastern Washington. It is probable that there are more lands capable of irrigation in the state than can be irrigated with available waters. This fact adds to the importance of the question of what to do with arid lands when no water can be put upon them.
METHODS OF IRRIGATION.
There are three methods in use in supplying water to the arid lands. The first and the one most generally adopted for obvious reasons is the gravity system. The waters are impounded in lakes or artificial reservoirs and carried thence in large main canals, winding about the hills so as to secure a low uniform grade. Once established, no other force is needed but the usual flow of the water.
Another method resorted to when the gravity system is impossible is to pump the water from the big rivers into smaller reservoirs leading to the canals, the pumps being kept busy only during the months in which the water is needed. This method is quite successful, but requires a somewhat larger annual expenditure. It is being used in some extensive projects, the water being taken out of the Columbia river.
The third method is in securing the water by means of artesian wells. This method is naturally limited to small areas, the projects being undertaken by individual private owners. Several spots have been found in the arid belt where this method is successful.
SOILS.
The soils over the entire areas of eastern Washington on the arid lands is a volcanic ash mixed with disintegrated basaltic rocks and some humus, varying in depth and in the amount of sand it contains. The low lands are usually more sandy and warmer and earlier in season. The depth of this soil is in some places 80 feet and generally so deep as to insure great permanency to its fertility. It readily absorbs and holds moisture, and is admirably adapted to artificial watering. In some spots there is an injurious surplus of alkali. It is generally covered with sagebrush and has the appearance of sterility, but upon cultivation under irrigation, produces wonderful results in quantity and quality of grains and grasses and fruits and vegetables.
GRAINS.
Wheat, oats and corn are successfully grown, but not in large acreage, because larger profits can be realized from other crops.