Southern California Edison Tehachapi Renewable Transmission Project

Client

Southern California Edison

Services Provided

Site investigation, Soil stabilization plan, Best management practices (BMPs) for cost and sustainability, Implementation of stabilization design, Construction oversight by QSP/D through the duration of the project, Regulatory liaison

Four wind turbines stand on a grassy landscape with trees and bushes in the foreground, beneath a partly cloudy sky during daylight.

Location

California

Project Practice Areas

Water & Wastewater, Water and Natural Resources

Type of Facility

Transmission

Project Specifics

Geosyntec provided turn-key water quality environmental services to Southern California Edison (SCE) on one of its largest ongoing construction projects, the Tehachapi Renewable Transmission Project (TRTP).

Geosyntec Scope of Services

Geosyntec evaluated transmission sites and substations for Construction General Permit (CGP) close-out, developed mitigation measures and construction plans, and implement soil stabilization strategies that allowed for successful termination of coverage under the California Construction General Permit for portions of the TRTP. Prior to Geosyntec’s involvement, site conditions and modeling attempts did not demonstrate readiness for termination. Geosyntec evaluated soil stabilization conditions along TRTP Segments 3 and 5 as well as several substations (Windhub, Whirlwind, and Highwind) and developed recommendations for termination, including site-specific Revised Universal Soil Loss Equation, Version 2 (RUSLE2) analysis which either directly demonstrated conditions adequate for termination or was used to verify new stabilization designs that were prepared. Based on the success of this project, Geosyntec provided similar support to SCE on TRTP Transmission Line Segments 7 and 8, and now has an as-needed construction stormwater services contract with SCE.

Notable Accomplishments

Geosyntec provided site review of existing conditions to make recommendations for termination under the California Construction General Permit.
Recommendations allowed the RUSLE2 model to be refined by the developer to better reflect site-specific pre-construction vegetation conditions, thus allowing termination.
Geosyntec coordinated with multiple SCE departments, and construction subcontractors to implement solutions and remove substation sites from permit coverage.
Geosyntec finished the project on budget and within an accelerated time frame, allowing SCE to eliminate CGP compliance costs.
Work was completed safely with safety tailboard for all field days.
Geosyntec provided well-written deliverables that received rapid approval from SCE, and supported quality field implementation of the approved design, which met regulatory approval.
Geosyntec exceeded SCE’s 40% disadvantaged business enterprises (DBE) goals.