Aspen managed the preparation of the Ormond Beach Wetlands Restoration Feasibility Plan for the California State Coastal Conservancy.

Aspen prepared the EIS/EIR to support a Corps of Engineers feasibility study for the removal of Matilija Dam on Matilija Creek, which is a tributary of the Ventura River.

The VCPWA-WP contracted Aspen to prepare the required CEQA/NEPA documents and permits for the Ventura River (VR-1) Levee Rehabilitation Project.

The Ventura County Watershed Protection District (District) proposes to rehabilitate the Santa Clara River levee system upstream of Highway 101 (SCR-1) to meet the levee criteria of both the Federal Emergency Management Agency (FEMA) and U.S. Army Corps of Engineers (USACE), and provide adequate protection from a one percent annual chance (formerly known as 100-year) flood event along the Santa Clara River for approximately 1,400 structures (residential, public, commercial, industrial, and agricultural) located in North Oxnard (El Rio area), Ventura County.

The VCWPD contracted Aspen to prepare the required CEQA/NEPA documents and permits for the Santa Clara River Levee Improvements Downstream of Union Pacific Railroad (SCR-3) Project.

Heavy rains and high flows in the Arroyo Las Posas, near Moorpark, California, eroded away an approximately 500 foot section of the northern bank of the Arroyo in the winter of 2005.

Because the potential for flooding along the Santa Paula Creek channel is considered life threatening, the USACE began construction of the flood control channel at Santa Paula Creek in June 1997.

Under contract to the California Department of Water Resources (DWR), Aspen Environmental Group prepared an Environmental Impact Report (EIR) for a proposal to change the seasonal flow release schedule of Pyramid Dam, located at the southern end of Pyramid Lake in Los Angeles County, California.