Report of the Board of Commissioners on the Irrigation of the San Joaquin, Tulare, and Sacramento Valleys of the State of California

Report of the Board of Commissioners on the Irrigation of the San Joaquin, Tulare, and Sacramento Valleys of the State of California

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1874 edition. Excerpt: ...may contradict themselves, as, indeed, they actually do in the Ganges Canal. The question of the proper velocity to be given may thus not admit of positive solution in some cases; but when the solution is possible, its importance cannot be overestimated. Upon this point may hinge the success or failure of the canal. If the velocity be too great, it may involve heavy expenditures for repairs, which finally may become so burdensome that the canal has to be lined with inasonry, as is the case on the canal of Caluso and others in Italy; or, if the velocity be too low, the canal-section has to be increased to carry the requisite quantity of water, thus entailing increased expense, and perhaps the canal must be closed once or twice a year for clearance, at a large outlay. The canals in India show great differences in the cost of repairs. In some cases the canal-section at its head for a mile or so is made wider than the general section to insure the deposit in this part, so that when clearance has to be made it is done at one place rather than all along the line. Then, too, the river at the head of the canal may silt up to the level of the crest of the dam, and the canal-supply may thus be cut off. This is generally provided for by placing a number of sluices in the dam or adjoining it, so arranged as to scour out a channel above and leave the canal-head clear. For clearance of flood-water in the canal, waste weirs are sometimes placed in its banks connecting with natural channels, which shall carry off the surplus water. DRAINAGE. Standing pools of water as connected with irrigation are, of course, the result of defective drainage, but they may be produced in different ways or proceed from different causes. lu India these cases occur when an...show more

Product details

  • Paperback | 50 pages
  • 189 x 246 x 3mm | 109g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236574346
  • 9781236574343