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Title:	Navigation Lock for Lower Granite Dam, Snake River, Washington : Hydraulic Model Investigations
Authors:	United States. Army. Corps of Engineers. North Pacific Division. Hydraulic Laboratory.
Keywords:	Locks (Hydraulic engineering) Washington (State) Lower Granite Lake Dam (Wash.) Snake River (Wyo.-Wash.)
Publisher:	United States. Army. Corps of Engineers. Walla Walla District.
Abstract:	The Lower Granite navigation lock is designed for maximum, average, and minimum lifts of 105, 100, and 87 ft, respectively. The filling and emptying systems are dynamically balanced hydraulic systems that include a unique arrangement of eight longitudinal floor culverts symmetrically placed around the center of the 86- by 675-ft lock chamber. Portions of the forebay and tailrace, two adjacent spillway bays, and elements of the lock chamber and hydraulic system were reproduced in a 1:25-scale model. Tests of the proposed system Indicated that turbulence and longitudinal hawser forces on barge tows in the lock chamber were excessive with a 4.0-min valve schedule at the design head of 105 ft. Pressures on the culvert roofs downstream from the filling valves were satisfactory when both valves were operated. With one valve, the minimum instantaneous pressure was -19 ft of water. Revised ports and baffles along the walls and over the ports were developed to reduce turbulence in the lock. Average maximum hawser forces of 6.2 tons on an eight-barge, 9-ft-draft tow and 9.9 tons on a four-barge tow in the original design lock were reduced to 1.4 and 1.7 tons, respectively, in the final design. A filling time of 9.8 min was obtained with a 1.11-min valve period and still maintained acceptable flow conditions, pressures, and hawser forces. Conditions were satisfactory when the lock was emptied in 11.5 min with two 1.03-min valves and an eight-barge tow. Air entraining vortexes over the intake manifolds should not occur unless the left filling valve only is used when the initial head is 105 ft and flow in adjacent spillway bays is more than 6,000 cfs per bay or when the initial head is 87 ft and spillway flow is slightly less than 4,000 cfs per bay. The 12-ft-wide culverts increased in height from 14 ft near the filling valves to 22 ft in a distance of 76 ft. A low average pressure of -5 ft on the culvert roofs downstream from the filling valves was desired to provide a continuous flow of air through the air vents and to prevent pressure reversals that might cause objectionable noises during filling. Low average pressures of 6, -6, and -11 ft of water were measured when the right culvert transition was moved downstream 25, 57, and 76 ft, respectively (two 1.11-min valves, initial head 105 ft). Pressures were within the range of cavitation when a single (right) valve was tested with the original culvert roof transition. (During testing the model air vents and culvert bulkhead slots were filled with water and sealed to prevent air intrusion and relief of low pressures.) The adopted transitions are 55 ft downstream from the original position, four 12-in.-diam air vents were used, and 16-ft-long steel culvert liners were installed downstream from the filling valves. Tests made with the prototype lock were duplicated in the model. Essentially good agreement between the two occurred.
Description:	Technical Report
Rights:	Approved for Public Release; Distribution is Unlimited
URI:	https://hdl.handle.net/11681/42920
Size:	102 pages / 17.41 MB
Types of Materials:	PDF/A
Appears in Collections:	Technical Reports