Environmental Activities

Next Steps

Project design refinements must be examined to determine if the Environmental Assessment described accurately the impacts of the project; therefore, an Environmental Reevaluation will be completed. This analysis will determine the effects of the design refinements on social, economic, and environmental conditions within the project area. This effort will be concurrent with on-going project design. A public meeting to present the results was held on June 21, 2007.

Traffic Noise

The impact of the Twin Peaks Interchange on area noise levels was predicted using computer models for the year 2030. The modeling predicted where Federal Noise Abatement Criteria would be exceeded and established where walls would be constructed for noise abatement.

Prior to the construction of noise abatement walls, meetings have been held with property owners affected by the walls to determine if the walls are desired. This has resulted in the elimination of several of the proposed walls, but most of the proposed walls, especially along Linda Vista Boulevard, will be constructed. A proposed 15-foot tall wall along the east side of Continental Ranch south of Twin Peaks Road will not be constructed.

In addition to noise walls, Twin Peaks Road west to Silverbell Road will be resurfaced with rubberized asphaltic concrete. Roadway resurfacing will improve drivability of the roadway and decrease the noise from vehicle tires.

Cultural Resources

The cultural resources inventory report prepared for the project recommended mitigation of impacts to two National Register of Historic Places-eligible properties within the project area. Mitigation will involve collecting and documenting information on one site and developing and implementing a pre-construction testing plan for the other site. Test pits will be excavated to determine if significant buried archaeological deposits are within the construction area. The testing program will likely require backhoes and other light excavating equipment.

Clean Water Act Section 404 Permitting

The twin bridges spanning the Santa Cruz River, the widening of the low flow channel in the Santa Cruz River, the redirection of a wash at the intersection of Twin Peaks Road and Camino de Mañana, and wash crossings of Linda Vista Boulevard would impact Waters of the U.S. As a result, a permit under Section 404 of the Clean Water Act and water quality certification under Section 401 of the Act will be required.

To receive Public Notices for activities being considered for U.S. Army Corps of Engineers permits under the Clean Water Act, you may register on-line with the Los Angeles District of the Corps by going to http://www.cespl.us/regulatory/mailinglist.htm.