AWA Gravity Supply Line

Project to upgrade and replace a complicated and outdated existing pumped raw water conveyance system involving pipeline between 2 pump stations in series that lifted water approximately 1100 vertical feet to the AWA Buckhorn Treatment Plant from the Tiger Creek Afterbay.  The new gravity-fed raw water transmission pipeline is approximately 6.6 miles of 20” & 24” HDPE, DI, Steel, and C905 Pipeline that delivers water from the Tiger Creek Regulator Reservoir to the Buckhorn Water Treatment Plant and had numerous design and construction challenges.  The majority of the pipeline is remote and involves construction on narrow roads, through narrow (as little as 10’) easements, and cross country on slopes exceeding 70% grade in places.  The pipeline was designed above ground in the steepest area and includes three aerial stream crossings, one State Highway crossing, one underground stream crossing, and one aerial flume crossing.  The pipeline intake is via a siphon at the reservoir and includes a CMU siphon control building at the reservoir.  The maximum pipeline pressures exceed 275 psi and vertical fall from the source reservoir to the treatment plant is only approximately 130 feet.  Liam Bailey completed the project predesign, design, construction plan preparation, and management of geotechnical, structural, and survey sub-consultants while an Amador Water Agency employee in 2007 and 2009.  Bailey Civil Engineering completed construction management of the project from construction notice to proceed in November 2013 to final project completion in 2016.