Projects Survey

Seneca Power Station Upper Reservoir Floor Relining

Mead Township, Pennsylvania

DLZ provided a staff of engineers, field technicians, laboratory technicians and surveyors to perform surveying services, construction monitoring and field and laboratory quality assurance testing for the relining of the reservoir floor.  During Pre-Construction, DLZ performed numerous surveys, participated in the Board of Consultant meetings with the Federal Energy Regulatory Commission (FERC) and confirmed the asphalt concrete mix designs in the laboratory.

All work was governed by FERC’s Chapter 14 Engineering Guidelines. This multi-million dollar construction project included milling 3-4 inches of the existing surface, placement of 3-4 inches of hydraulic asphalt concrete over the entire 86.8 acres of the reservoir floor, 12.6 acres received 3 layers of geosynthetic materials (1 layer of geomembrane and 2 layers of geotextiles), 8-12 inches of compacted asphalt millings and 4 inches of open graded asphalt concrete beneath the hydraulic asphalt concrete.

DLZ was responsible for the selection and recommendation of sub consultants to perform SUE (Subsurface Utility Engineering), GPR investigation (Ground Penetrating Radar), and video inspections. Throughout construction DLZ provided additional support for the FERC mandated board of consultants with various daily construction reports, dam inspections and monitoring. During construction DLZ performed detailed Surveying and 3D Scanning of the basin surface to define the pre-milled, milled and final paved surfaces.

The site survey included both area and volume calculations reported on a weekly basis.  Survey monitoring of the entire upper reservoir and certain sections of the earth dam were established in order to verify any horizontal and vertical movement. Deliverables consisted of a twenty-four page as-built plan set which included a survey control plan, milling progress plan, hydraulic asphalt paving plan, truck ticket placement plan, open graded asphalt plan, geomembrane plan, inspection of structures plan, GPR investigation plan, asphalt coring plan, and sealing installation plan.