AZ vs. CA:04 California Exhibits, Vol. IV; Nos. 151-192

page 80

80 THE ALL-AMERICAN CANAL. similar material as a temporary means and by the irrigation of the sand areas, upon which grass and other shrubs are started. The soil of the mesa is composed of sandy material with sufficient gravel mixed in so that when distributed in the spoil banks it will be stable from any wind movement. These spoil banks are to be spread out so as to cover a strip as wide as construction methods will permit on each side of the canal. During the period of construction and the first years of operation, temporary barriers will be necessary, or the sand that drifts behind the spoil banks upon the 30-foot berm or into the canal must be removed. To cover this item during the period of construction we have roughly estimated 500,000 cubic yards will have to be so moved from the canal prism. When the canal is in operation the area for 1,000 to 1,200 feet behind the spoil banks can be irrigated by pumping, so that grass and shrubs may be started, to hold the drifting sand. This method can not be practiced through the three large sand ridges. The sand entering the canal prism in these sections can either be removed by suction dredges from the canal or can be removed from the canal berm before it reaches the water section, by steam shovels and cars. (d) While the blow sand is a menace and will need constant attention to prevent its encroachment upon the canal, our observations, while not extending over a sufficient time to lead to final conclusions, have, however, led us to the opinion that it is not an obstacle to the successful and economical operation of a large canal. At least two years will lapse before construction on this section can be undertaken, during which time further studies concerning the sand movement and methods to reduce their movement should be carried on. CLASSIFICATION OF MATERIAL. (a) From Laguna Dam to siphon drop the character of material is either shown where exposed by the excavation of the canal or in the abrupt faces of the bluffs just above the present canal prism or in the log of the original test pits. The rock is confined to the first 76 stations below the dam. The balance of this section is composed largely of sand, gravel, and loose rock, with some sand that is found well compacted. Below station 76 the material is of a character that can be handled by^team shovels or drag lines without the use of powder. From siphon drop to Araz 11 test pits were put down several years ago on or near the line of the proposed canal, by the Reclamation Service. These show the material to be sand, gravel, and compacted sand, all of which can be handled with steam shovels and drag lines without the use of powder. From Araz to a mile west of the west edge of the sand hills during the last 14 months a