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Show ARROWRDCK DAM IS ! ENGINEERING MAHVEL Engineer D. F. Seerey Describes De-scribes Construction Near Boise. LOG CHUTES PROVIDED Modern Machinery Installed to Protect Dam From j Heavy Drives. Special to The Tribune. j OGDEN, Feb. 27. AVhy visit thf ' ; Panama canal in order to see a great J engineering accomplishment when the Arrowrock dam and various construe- j tions connected with it are almost mar- ; velous? This is the confidential advice ; of P. F. Seerey, logging engineer for the j Fourth forest district, who has just re- ' turned from an Idaho trip. He was in conference with officers of the Id:iho- ; Oregon Fruitgrowers' association, and) also with F. E. Weymouth, an ofiicer of j the United States reclamation service. ! who is located at the Arrowrock dam ; near Boise. ! : According to llr. Seerey. the use of la- I i bor-saving devices has been so success- t ful that this project will be completed ! within the estimate and soon the gigan- tie concrete structure connecting the granite walls of the Boise '260 feet above ; the level of the river with ninety feet i of foundation below will impound a lake ; I of water reaching up the middle and 1 south fork of the stream a distance of j seventeen miles The total width of the ! ; great dam is 10,5 feet. j ! Lumbermen Favored. , Concerning the special attention that i has been given to the lumber industry j iu the construction of the Arrowrock j dam, Mr. Seerey says: j I Illustrative of the foresight in j f building this dam is the arrange- 1 ! ment for transporting large logs ! ! ovpt it. which can thus in the r'u- 1 iiiro, as in the past, be brought ! down the Boise in the large river ; ' drives. The Boise river has from earliest times been an important . i channel of transportation, large io's : '. of yellow pine having been floated ! down the river in the spring freh- ; i cts from the times of early settle- . i menr. . j It will be necessary to introduce I a protective breastwork so that not only logs but possibly floating trees I and other heavy debris will not come in contact" with sudden impact nr in great quantities with the dam. Probably if the drive is a large one it will he necessary to collect it in several booms along the shore of the 1 artificial lake, these to be brought down one at a time and taken over the dam to the stream below to resume re-sume the journey to the sawmill. Chains Catch Logs. At the left bank near the dam a boom will convey the logs into a chamber and at the right hand side of this chamber tour chains are au- : '-hored which will run parallel at four-foot intervals to a drum on the shore propelled by electric motor. : These chains are of sufficient lecgth to drop in the form of loops below the surface of the water in the chamber, and as logs float in the drum will be started, tightening the chains and thus raising the Ings so that the inclined p!ane of the chains rolls the logs to the right and the farthermost is caught on rollers equipped with spikes which carry it at once to the mouth of the chute, down which it descends to the rier below. The rollers are run automatically by moto in such way that four or five" logs introduced into the chamber at a time will be sent down the chute four feet apart. Chutes Steel Lined. Tne "dry" chute is of concrete lined with hVel rails and has a Ot per cent grade. The descent of th logs will be governed by a bull r.Lain controlled by motor. Xear the bottom the grado is gradually changed to 30 per cent, and at the bottom it turns to an upward curve so that the Jogs are landed flat in the river. The Barber Lumber rompanv has completed its twenty or th:rv Triles of railroad from the line of the re 'amtion service up Moorn'g crei; to the large tract of fine timber pur-'Lased pur-'Lased from the state of Idaho. A -ood road bas been built, with a steel r ridge across the Boise river at the ' mouth of Moore's creek. |