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-3- November 1, 2011 <br />approximately 40 feet where the concrete bulkhead upstream of the control valves is <br />located. <br />The tunnel surfaces and concrete were found to be in generally good to satisfactory <br />condition. There were a number of cracks and small holes observed in the tunnel walls that <br />displayed seepage flows that will require repair to return the concrete to a more watertight <br />and acceptable condition. The floor of the tunnel was not visible and completely covered in <br />an approximately 8 inches of silt and silt -laden flow. Additional inspection of the floor is <br />recommended after the silt has been flushed from the tunnel and once upstream flow control <br />is established during the rehabilitation process. <br />3.3 Rockcut Intake Tunnel From Concrete Tunnel to Bulkhead <br />This section of the outlet works tunnel was typical for what would be expected for tunnel <br />bored using handheld equipment and completed in 1929. The cross section was not <br />uniform with many jagged rock edges and points. The exposed rock face was found to be <br />sound with no lose or displaced rock material. The tunnel floor was generally smooth and <br />even. <br />3.4 Rockcut Intake Tunnel Concrete Bulkhead <br />The bulkhead concrete was found to be smooth on both the upstream and downstream side <br />with no cracks or holes in the concrete. Joints against the rockcut tunnel were tight and the <br />rock face at the joints was sound. Previously documented inspections by the SEO found <br />little or no seepage through the bulkhead on the downstream side under full reservoir head. <br />The current control configuration with the valves on the downstream side of the bulkhead <br />relies on the pressure integrity of the bulkhead and the 30 -inch pipe penetrations through <br />the bulkhead. If the bulkhead were to fail and lose pressure integrity, the result would be an <br />uncontrolled reservoir release. <br />3.5 30- Inch - Diameter Intake Pipes From Bulkhead to Control Valves <br />The 15- foot -long pipe sections from the downstream end of the bulkhead to the control <br />valves were found to be severely corroded, thin in wall thickness, and generally in very poor <br />overall condition. The bottom half of the pipes was bedded in concrete. If the pipes are to <br />be used for outlet rehabilitation where pressure integrity is required, replacement or lining <br />will be required. <br />3.6 Control Valves <br />The two 30- inch - diameter control valves will only open approximately 50 percent before the <br />operators become very difficult to turn and the operators have more than 50 turns of slack <br />before the valve stems begin to move. The right valve stem is relatively straight and vertical <br />but the left valve stem is bent near the bottom of the vertical rockcut shaft so that it can line <br />up with the left valve, which is not located under the vertical rockcut. Previously <br />documented inspections by the SEO found little or no seepage through the valve faces and <br />seats under full reservoir head. The valves and operators will require replacement or repair <br />if they are to be used for rehabilitation of the outlet works. <br />3.7 Downstream Rockcut Discharge Tunnel <br />The downstream rockcut discharge tunnel was found to be similar in cross section as the <br />upstream tunnel but undulating in alignment. The floor of the tunnel was found to be very <br />irregular with holes and high points differing by as much as 2 vertical feet. The rock <br />