Douglas Island news., 1905-01-18
AN ALASKA DAM AND PLUME.

Juneau, Alaska, has beeu designed and
 built to intercept and divert the water, at all stages of Gold creek, for the pur- pose of draining the basin, and con- trolling the water so that hydraulic
 operations can be started and carried
 on with safety. The dam is built at the upper end of the basin diverting
 the water into the Hume which is con-
 structed along the south side of the
 basin and returns the water to the creek channel at the lower end of the
 basin. All the drainage water on the
 south side is picked up in small side
 fumes and dumped into the large
 Hume. The drainage from the north
 side is handled in another way. The
 dam and Hume were put into success ful operation on November 27, 1904, in the presence of 300 residents of Juneau with appropriate ceremonies. The dam is a solid, rock-filled crib resting on bedrock and gravel. 24 feet wide and F feet deep, with piers and abutments rising 13 feet higher and also rock fill ed. Upon this foundation, between the piers and abutments, are placed the intake of the Hume, 42 feet wide, and the superstructure F feet high, in 20 sections of 6 feet each, any one of which can be removed and accumula- tious of gravel and debris sluiced out over the dam. The dam is not intend ed to have water overflow it's crest The entrance to the Hume is 42 feet wide and F feet deep and reduced by curves in the distance of 7G feet to the head gates iu the Hume 10 feet in the clear. The water is controlled by two gates 10 feet inches by F feet inches, weigh ing over 2OOO pounds each and moved by a train of gears by which two men can operate the gates at any stage of the water There are also twelve gates in the side of the headpiece 4x4 feet operated by special gearing, which have a greater combined discharge than the carrying capacity of the Hume, in case such an emergency is required. 1. Out of these gates such water will be discharged as will be required for by wash in the operation of the mine, the water for piping being obtained from a high line Hume on the north side of the basin. The face of the dam is two thicknesses of 2-inch plank, laid to break joints, and is carried down be- low the foundation crib as much as feet to tight gravel, and puddIed with clay A hydraulic jet pump was used in sinking the facing. The structure is 196 feet over all.
 The Hume is 425O feet in length and 20x9 feet in cross-section on a grade of l.66 feet per 100 feet, except at the head where there is an increased grade for the first 400 feet to rapidly bring the water up to its velocity The sills are 6x8 inches and the posts and caps are 6x6 inches; the sides and bottom are of . 2-inch plank battened and the bottom has a false bottom of 1 inch making a . total thickness of 3 inches. The pro- jectiDg ends of the caps and sills are sway, braced to the posts top and bot tom to overcome the wind strains. The trestle work is q feet wide with bents 12 feet, centers of hewed mud siIIs, SKIS . inch posts and caps carrying six string CTS of 6x12,inch timbers. There is about 22jO feet of trestle, the highest of which is + feet. There is about 2OOO feet of grading through earth and rock 26 feet wide. The Hume has a capacity ofabont 24O,OOO cubic feet of water per minute, and is designed to carry all the flood waters of Gold creek. In the construction of the Hume and dam 100000 feet of lumber has been used, over 5000 linear feet of hewed timber, and about twenty tons of nails and . drift bolts. Work was commenced . June 15 and the structure completed Novemb Der 20. 1904, after being subject ed to numerous delays through short, age of material.
 A tunnel 2Ooo feet long taps the gravel in the basin 90 feet below the surface and is being extended 400 feet farther, 8xS feet in the clear, when an upraise will be made on the surface and hydraulicking com- menced next season.
 This operation was commenced after a favorable report and careful examina- tion by w. H. lille of Philadelphia, i with Eastern capital. The work of ]