Depth of the California Aqueduct

The California Aqueduct (part of the State Water Project) is an open concrete-lined canal, not a deep tunnel. Its depth varies by design section:

• Typical depth: 8.5 to 20 feet (2.6–6 m)
• Average depth: ~12 feet (3.7 m)
• Width: 40–110 ft at surface; 12–30 ft at bottom (trapezoidal)

Why So Shallow?

• Gravity flow: Gentle grade (0.0001–0.001 ft/ft) moves water 444 miles from Delta to SoCal
• Evaporation management: Wide surface increases loss, but depth balances flow velocity & seepage
• Maintenance access: Shallow allows easy inspection, repair, debris removal
• Cost: Excavating deep tunnels over 400+ miles would be astronomically expensive

Key Structures

• Pumping plants (e.g., Edmonston: 1,926 ft lift over Tehachapis)
• Siphons (under rivers, faults)
• Reservoirs (San Luis, Pyramid, Castaic)

Depth is functional, not monumental. The engineering marvel is length and lift, not depth.