Information on Construction for Seismic Remediation
Status Update - November 2002
The Saluda Dam seismic remediation project has progressed to a point where all major design issues are concluded, construction and environmental permits have been obtained or have been applied for and shortly will be issued, and the start of major construction is approaching.
Barnard Construction Company was awarded the general contract for the major civil work on August 12, 2002, and is currently mobilizing men and equipment to the site and performing preliminary construction activities.
Revised Schedule and Plans
The contractor has rearranged the design engineer's original schedule and plans to construct the rockfill dam foundation portions first. They will start with excavation at the toe of the existing dam some time during January 2003. Excavations for the foundation of the new concrete dam sections may commence in May 2003.
Critical Construction Phases
The critical construction phases of excavation at the toe of the existing dam for the foundation of the new dam involves lowering the phreatic (or water table) surface in the existing dam to increase stability and guard against pore pressures that could lead to a process termed "piping." This is accomplished by lowering the reservoir, and installing a system of pumps and wells on the downstream slope and toe area. The owner, SCE&G, elected to manage this portion of the construction directly, as it required planning and installation long before selection of the general contractor. A large fleet of well drilling rigs have been massed on the downstream slope during the late summer and fall months to complete this work and to install a vast array of instrumentation to monitor the effectiveness of the dewatering effort and the dam response to excavation.
SCE&G has recently obtained the services of a renowned dewatering consultant to aid in maximizing the efficiency of this system and ensure that the design drawdown in the embankment is accomplished prior to excavation. Initial tests of portions of the dewatering system have been encouraging.
The FERC and SCE&G have held numerous meetings in the last year to inform the public of the upcoming construction. Presentations regarding the project and its progress will continue to be offered by SCE&G and/or FERC.