The Delta Conveyance program facilities, including tunnel shafts that are currently proposed to remain following construction, would be constructed at elevations greater than the 200-year flood event and projected sea level rise at year 2100 with considerations for freeboard and wind fetch waves.
June 12, 2020Are the maintenance and retrieval shafts being kept or filled after construction of the project?
June 12, 2020As currently proposed, the shaft would be constructed with a diaphragm wall or concrete shell that would extend to the bottom of the tunnel where there are structurally competent soils; therefore, the tunnel shaft would not be expected to settle. The soil on top of the ground at the shaft locations would be treated with ground improvement methods as necessary to stabilize the site for equipment and the shaft pads.