Environmental Consulting

Alton Parkway Extension EIR | Orange County, CA

City of Lake Forest and City of Irvine

Lead Agency

County of Orange


CEQA Documentation (EIR)
Focused Surveys for Special Status Plants, Least Bell’s Vireo, and Southwestern Willow Flycatcher
Noise Analysis
Jurisdictional Delineation
Habitat Mitigation and Monitoring Program
Habitat Restoration

Complex Roadway Improvement Project

The Alton Parkway Extension improves traffic by closing the 2.1-mile gap between Alton Parkway and Irvine Boulevard, just south of the State Route 241 toll road. Due to multiple jurisdictions (cities of Irvine and Lake Forest, County of Orange, and U.S. Department of Defense) and multiple land owners (County of Orange, the Navy, and Shea Baker Ranch Associates), this was a complex project.

BonTerra Psomas prepared the Environmental Impact Report (EIR) that addressed a full range of environmental issues, with the most critical being biological resources, land use, hydrology and water quality, traffic, and visual impacts. The initial preferred alignment would have required redesign of the approved Orange County jail expansion. By working with all stakeholders, the solution allowed the road to utilize jail property and maintain the court-approved conceptual design for the jail while still enhancing wildlife protections. The EIR facilitated implementation by multiple agencies by clearly identifying the mitigation responsibilities and developing separate Mitigation Monitoring and Reporting Programs for the County of Orange and the City of Lake Forest, the two agencies responsible for implementing the project.

BonTerra Psomas also prepared the Jurisdictional Delineation Report for the County of Orange portion of the site; completed focused surveys for special status plants, southwestern willow flycatcher, and least Bell’s vireo; and prepared a Biological Technical Report. A Habitat Mitigation and Monitoring Program was also prepared and a restoration program is being facilitated, providing compensatory mitigation for project impacts.