Tioga Outlet Works, Tioga and Hammond Lakes, Susquehanna River Basin, Pennsylvania. Hydraulic Model Investigation.
Final rept. Mar-Jun 74,
ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MISS
Pagination or Media Count:
A 125-scale model of the Tioga outlet works was used to determine the adequacy of the stilling basin to perform as desired for discharges up to 15,860 cfs, to study flow conditions in the exit channel, and to determine minimum riprap requirements for the exit channel. A schematic of the intake tower, the outlet conduit, the stilling basin, and about 600 ft of the exit channel were reproduced in the model. The original design stilling basin performed satisfactorily for discharges ranging from 2,000 to 14,000 cfs however, flow separation and adverse vortex action occurred with lesser flows and a pulsating jump that overtopped the basin walls occurred with greater flows. Performance with low release rates was determined for both single- and double-gate operations. Recommended changes to the original design stilling basin included widening the basin from 55.5 to 72 ft, decreasing the flare of the outlet transition from 1 on 4,683 to 1 on 6, raising the basin apron 4.5 ft from el 1005.5 to 1010.0, raising the elevation of the sidewalls from 1043.0 to 1048.0, and lengthening the basin approximately 30 ft to the 38.64-ft-long horizontal floor at the outlet portal. The minimum size riprap required for stability in the exit channel was determined with the design discharge of 15,860 cfs.
- Civil Engineering