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I I I I I I I I I I I I I I I I I I I turbine can be above the penstock outlet to avoid cavitation. Because the elevation in this configuration is 10 feet, cavitation may occur and result in shorter impeller life. Piping Plan B (Figure 7.2) is a modification of the first alternative, except that the turbine is placed on the floor to eliminate the pedestal and cavitation problems. The inlet piping to the turbine is more complicated. The piping has a 180 degree bend and another 90 degree bend to the turbine. The valving is the same as for Plan A. The bypass and outlet piping are simpli- fied. The major problem with this configuration is the friction head loss through the piping which is 0.2435Q2 in the inlet and 0.0508Q2 in the outlet, for a total of 0.3384Q2 including the 15% contingency. This would result in 57 feet of head loss at 13 cfs and 27 feet at 9 cfs. Piping Plan A (Figure 7.3) is the simplest piping plan and has the least friction head loss; 0.1352Q2 in the inlet and .0508Q2 in the outlet for a total of 0.2139Q2 including 15% contingency. The head loss at 13 cfs is 36 feet and at 9 cfs is 17 feet, which is significantly less than the other configura- tions. The major problem with this plan is that the concrete block encasing the first 90 degree upward bend must be removed so that the bend can be removed and the pipe extended. The concrete is an approximate two-foot cube which will probably have to be jack- hammered out. Care will be required so that neither the chamber nor the pipe in the concrete is damaged. The bend will be cut off and an 8-inch to 10-inch reducer welded to the existing pipe. A new 10-inch gate valve will be installed after the cone, followed by an upward "T" for the bypass pipe. Butterfly valves 7.0-7