Presidio Parkway (Doyle Drive Replacement) Native Plant Salvage and Erosion Control

San Francisco, Ca 

CalTrans
Fall 2009

 The Doyle Drive replacement project is designed to improve the seismic, structural and traffic safety of this roadway. Construction began in December 2009 and is expected to be completed in 2011.  Hanford ARC contracted with Caltrans in July 2009 to begin preparation and provide ongoing support for several aspects of this project.  Our scope for the project includes native plant salvage and temporary nursery facility construction (contracted as prime), civil contractor access establishment and staging area construction, erosion control and BMP maintenance, and protective fencing (contracted as subcontractor). 

In mid July we mobilized to develop and stabilize construction routes and staging areas for the numerous contractors on the project.  The staging and access areas will be utilized over a period of approximately two years.   Stabilizing these areas required temporary, durable geotextile materials and rock.

The applications for the staging areas included cellular confinement systems (CCS) secured onto existing graded surfaces.  We cleared and prepared the areas with approximately 12,000 square yards of subgrade enhancement geotextile (Mirafi 570 HP) suited for paving.  We filled and compacted the CCS with approx. 700 tons of ¾” drain rock to prevent surface damage from heavy equipment and trucks.

While completing the access and staging area work, we began the plant salvage contract.  This included preparation of a temporary nursery to hold the 300-400 native plants to be salvaged under our contract and propagated by the Golden Gate National Parks Conservancy (GGNPC). These plants will be replanted at the end of construction.  GGNPC, as a subcontractor under our contract, will water and maintain the plants.  In addition to the plants, we collected native seed to be used for propagation by GGNPC.

To protect both ecological and culturally sensitive resources, we also subcontracted to construct temporary protective fencing.  In the 2009 season, we installed a total of 4,575 LF of temporary reinforced silt fence (TRSF) and 2,365 LF of environmentally sensitive area (ESA) fence throughout the project.  We also have installed approx. 4,000 LF of tree protection fencing around specific trees and groupings of native plants to be retained.  To protect a newly completed wall and the historic pet cemetery we placed approximately 200 feet of K-rail as a perimeter.

In addition to the protective fencing, under the direction of the Caltrans Regional SWPPP Inspector, we have installed and maintain most BMPs on the Doyle Drive project.  We have installed approximately 37,000 LF of bio-wattles for erosion control on slopes and bare areas.  Approximately 600 gravel bags have been placed by our crew around drain inlets and as water diversions.  Finally we completed 2.5 acres of hydroseeding, ¾ acre of straw mulch and tack, and hand spread 480 bales of rice straw.