- Fairly rough, large ponds, designed to increase concentration to a high enough level to remove algae (“limu”) and crustaceans (“bigots”) - the salt worker’s enemies. This area is not mandatory, but very practical, and it appeared fairly late in the history of the salt marshes. It can typically represent 10% of the salt works.
- Smaller ponds, and thus more adapted to the meticulous maintenance along the bends, enabling a regular flow of a fine film of water (1cm). They are as level as possible, with the exception of a small ditch (fossé) along the dykes or bridges (carrière). These are the most efficient ponds for the concentration of sea water. Their surface often increases the further away from the sea they are, and they represent 30 to 40% of the salt works.