Los Angeles, CA

Pure Water Southern California

Metropolitan Water District of Southern California (MWD)


MWD is developing the Pure Water Southern California Program (Program) to provide a drought-resistant water source that would produce up to 150 million gallons (568 ML) of water for 15 million people in Southern California. The components of the program include an Advanced Water Treatment Plant and distribution system of 40 to 60 miles (64 to 97 km) of large-diameter pipeline and pump stations to convey the highly treated reclaimed water from the Los Angeles County Sanitation Districts’ Joint Water Pollution Control Plant in the City of Carson to various groundwater basins for groundwater recharge purposes.

Fast Facts
  • Produces up to 150 million gallons (568 ML) of water for 15 million people
  • 40 to 60 miles (64 to 97 km) of large-diameter pipeline and pump stations
  • Alignment alternatives included 150+ trenchless and tunneled crossings

Scope of Work

Through a series of contracts, Delve Underground has conducted peer review, conceptual alignment studies, and conceptual design and permitting support for multiple trenchless and tunneled crossings for the Program. 

Environmental Planning Phase – Conceptual Design of Tunnels and Trenchless Crossings: Delve Underground has undertaken the role of tunnel and trenchless designer for the initial conceptual design of conveyance pipelines. The initial backbone pipeline studied includes up to 40 miles (64 km) of 7‑foot-diameter (2.1 m) pipeline

Feasibility Study Phase — Conceptual Review of Three New Tunnel Alignments: MWD engaged Delve Underground’s experts for a high-level review of three alignments proposed as tunneled or trenchless installations. The conceptual review focused primarily on the big picture” elements associated with three pipeline segments 2.6 to 4.6 miles (4.2 to 7.4 km) long in developed urban environments.

Feasibility Study Phase — Conveyance Systems Trenchless Crossing Peer Review: Delve Underground reviewed the trenchless methods proposed for more than 69 crossings and discussed alternative methods as appropriate.

Challenges & Innovations

Our review team offered insights and recommendations on the programmatic considerations for a significant number of crossings, including project delivery, contract packaging, and risk management, which can greatly impact the cost and schedule of the program.