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Deepwater Construction Project

February 27, 2018

Location: Upper & Lower Crystal Springs & San Andreas Reservoir, San Mateo County, California

Project Overview: Contain construction sediments within each reservoir’s work zones used to provide seismic and hydraulic upgrades at the three reservoirs built between 1888. Demolition, new tunnel liners, refurbishment or replacement of water management infrastructure with frequent barge traffic with turbidity managed to utilize 9,150’ of tapered TYPE 3 HD turbidity curtains 

ABASCO Contribution: Product Design: manufacture & installation support

  • TYPE 3 tapered curtains ranging from 5’ to 110’
  • Dual 5/16” top tension cables & 3/8” HG chain
  • Aluminum ASTM Universal Slide Connectors
  • 14”, 16” and 22” flotation
  • 22 oz PVC coated fabric with skirt welded in vertical lengths; reinforces fabric corners and grommet area
  • AS 40 Anchor Packages with Danforth anchor, chain leader, 5/8” poly rope, A-2 Anchor Buoy and 5/8” painter line

Project Challenges and Features –

  • Type 3 HD curtains provided depth to 110’ depths in 50’ sections
  • Strong winds up to 45 mph at San Andreas
  • Restricted NTU release
  • Manta Ray and Danforth anchor utilized with detailed design
  • Two vestibules required and gates
  • Sulfate reducing bacteria caused H2S corrosion
  • Long term application from 3/11 to 5/13
  • Spreader bar utilized on curtains up to 1,500 lbs