• Task 1: Repair measures shall commence at the exterior foundation wall to repair that area and limit water infiltration into the structure. Prior to any repair measures: o A dive inspection shall be performed at the exterior northeast corner of the Office Building to obtain a more detailed understanding of the extents of voids/leakage present at the silt level at that location. o Erosion and sediment controls shall be established. o Silt removal shall be performed prior to the dive inspection. Task 2: Once the dive inspection has been performed: o Repair extents shall be refined, and a steel bulkhead shall be fabricated. o Normal water levels will be maintained during the execution of Work at this location. o Deteriorated and unsound foundation wall material at the exterior northeast corner shall be removed and disposed of off-site. o The repair entails the installation of hooked dowels, reinforcement, and waterstops in preparation for a steel bulkhead installation. o The steel bulkhead shall be lowered into place and anchored to sound material of the existing structures. o Concrete shall be tremie placed into the bulkhead to seal voids and provide a structural overlay at that location. Task 3: Once repairs have been completed at the exterior corner of the Office Building: o Repairs to the interior Water Chamber may be performed. o Intake gates will be lowered and the area allowed to drain into the tailrace. o First, access shall be established to the Water Chamber through the 32-inch-diameter hatch in the Powerhouse Building Turbine Room floor. o All leakage inside the Water Chamber shall be observed and reported to the Engineer. o Additional repairs may be required if leakage has not been stymied by exterior bulkhead repair...
