The general plans for Riverside County and for the cities of Chino and Ontario forecast that over the next 20 years, the project area will have approximately 59,000 new residential units, 1,140 acres of new commercial developments, 970 acres of new light-industrial development, and several new schools and colleges. Southern California Edison (SCE) proposes to construct a new 66/12kV substation (Kimball Substation), four 12kV distribution lines, 0.4 mile of new 66kV subtransmission line, and to upgrade existing 66kV lines to meet projected electrical demand requirements and improve reliability in the eastern area of Riverside County and southern portions of the cities of Chino and Ontario.

The project is required to improve the reliability of the electrical power system and meet the projected load growth. SCE plans to submit a PEA to the California Public Utilities Commission in support of an application for a Permit to Construct. EPG was retained by SCE to prepare the PEA in compliance with CEQA regulations. The studies included environmental inventory and analysis of a proposed 2-acre substation site and two alternative substation site locations in San Bernardino and Riverside County that would be suitable to interconnect the 66kV and 12kV systems. EPG conducted the inventories and assessment for land use, visual resources, soils, geology, water, and air quality. The project also includes the preparation of biological resource surveys (flora, fauna, and threatened and endangered species).