Seawater Intakes


Seawater can be used to supply Sea Spa Centers, swimming pools, fish and shellfish farming infrastructures, aquariums or desalination plants.

Many different types of seawater intakes exist. The type of seawater intake needs to be analyzed using numerous criteria like water quality (especially for desalination), water pressure, tides, and particularities of the location. The environmental and economic factors will also help determine an ideal solution.


The different seawater intakes:

First, there are the direct seawater intakes in the open sea (on the surface or deep underwater). For example, the headrace canal can serve as a seawater intake to bring water to the designated area. This channel is used for large water flows such as for hydroelectric or electronuclear plants.

A direct seawater intake can also be done using wells or suction tulips (submersible pump) which lead the water to a pumping station through pipes. There are also seawater intakes with strainers to be able to filter the water.

Then, there are seawater intakes that work using coastal catchment wells. Coastal wells are recommended when the quality of the water varies throughout seasons or when there are high turbidity peaks. A vertical coastal well can obtain 200m³ per hour while a radial well can obtain up to 1000m³ per hour. These wells are like regular wells in the water table. They can obtain water with little organic matter; however the pressure is low.


These seawater intakes are typical for desalination plants or any other projects requiring a seawater intake but there are also seawater intakes that can get water underneath the sand surface or underwater. Drains are installed under the sand, parallel or perpendicular to the coastline.


At ECOPLAGE, we recommend this seawater intake by putting drains parallel to the shoreline. Seawater catchment through the sand will then pass through a pumping station before reaching the building to provide seawater (for pools) or to provide a heat pump to heat and/or cool the infrastructure (heaters/AC). Sand is used as a natural filter and the seawater is highly filtered which is important to avoid clogging problems.

These drains prevent underwater works which are costly and need regular maintenance. Moreover, many pre-filtration processes usually used on ordinary seawater intakes can be removed from this system.

The water flows in the drains by gravity and the negative impacts on biodiversity are minimized compared to other underwater seawater intakes.


Our drainage system Enerplage® is installed on a few locations. It provides water, heating and air conditioning to sea spa centers: La Baule-Escoublac, and Saint-Jean-de-Luz. We also provide highly filtered seawater to the biggest aquarium in Europe: Nausicaa.

Seawater from the Enerplage system is ideal for marine geothermal energy (AC/Heating with a seawater heat pump), for desalination units and also for pools and basins that need seawater.