Route 580 Westbound High Occupancy Vehicle Lane Widening

Route 580 Westbound High Occupancy Vehicle Lane Widening

The Permittee proposes to widen westbound 580 along a 13.1 mile stretched to accommodate a new High Occupancy Vehicle (HOV) widening. The proposed widening will impact DFG stream jurisdiction of the following waterways: Arroyo Las Positas, Arroyo Seco Creek, and Tassajara Creek. The California Department of Fish and Game (DFG) is issuing Streambed Alteration Agreement #1600-2010-0284-R3 for this Project. Two bridges will be widened over Arroyo Las Positas. All bridge piers will be installed outside of the active channel, the new piers will require pile driving for installation. Arroyo Las Positas will be diverted around the construction site in order to protect the creek during construction activities. This work will result in approximately 1000 square feet of permanent shading of the creek and 12,000 square feet of temporary impacts from the creek diversion. The concrete box culvert at Arroyo Seco Creek will be extended to accommodate the HOV widening. Approximately 54 cubic yards of concrete and rock slope protection will be place in the waterway, resulting in approximately 1200 square feet of permanent loss of native riparian habitat. The bridges crossing Tassajara Creek will be widened into the median over a concrete lined channel causing temporary impacts from the creek diversion and permanent shading impacts.

Dublin, Livermore, Pleasanton

Alameda