Seawater harvesting systems for desalination

Service Specifications for Seawater Intake Systems for Desalination

Seawater intake systems for desalination plants require reliable, precise construction solutions that have minimal impact on the coastal environment. Trenchless technologies enable the construction of deep intakes, subsea pipelines, and feed tunnels with high hydraulic and environmental safety. This service is defined by the following technical parameters:

• Main applications: Intake tunnels and microtunnels, pipelines carrying water to the plant, intake wells, underwater inlets, connections to pretreatment galleries, and crossings under beaches, boardwalks, or port areas.

• Construction methods used: Ground-controlled remote-operated microtunneling, pipe jacking, Direct Pipe® for steel pipelines, and ancillary civil engineering work for intake wells and intake structures. For offshore sections, integration with mooring and underwater maneuvering systems.

• Terrain and coastal environment conditions: Coastal soils, saturated sands, alluvial deposits, and a constant water table. High pressures, permeability, coastal dynamics, and the potential for sediment intrusion into the pipeline are taken into account.

• Required diameters and flow rates: Selected based on the desalination plant’s design flow rates. The conduits may be non-accessible (concrete, steel, or HDPE pipes) or accessible tunnels in higher-capacity projects.

• Typical lengths of water intakes: Sections ranging from tens of meters below the shoreline to several hundred meters out to sea, depending on the distance from the intake area, water quality, and the geotechnical characteristics of the coastal platform.

• Civil works requirements: Intake and collection wells, offshore platforms, access points for heavy machinery, space for a sludge treatment plant and pumping equipment, as well as safe areas for the fabrication, welding, or assembly of large-diameter pipes.

• Integration with underwater construction: Coordination with marine work crews for connecting the intake, installing diffusers or inlet structures, final alignment, and verification through underwater inspection or ROV.

• Water Quality and Sediment Control: Design of the intake system to prevent the ingress of sand or solids, thereby maintaining the efficiency of the desalination plant’s pretreatment process and reducing maintenance and wear.

• Quality control and verification: Monitoring of face pressure, thrusts, advance, excavated volume, and alignment during tunnel or microtunnel construction; CCTV inspection, watertightness tests, and geometric verification of the alignment. In marine construction, verification of the alignment and stability of the pipeline.