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Which conditions are needed to produce salt by solar evaporation of seawater?

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Cluster of translucent, white salt crystals with sharp cubic shapes viewed under a microscope at high magnification against a dark background. — salt Salt crystal magnified.

To produce salt (sodium chloride) through the solar evaporation of seawater, specific environmental and structural conditions must be met to ensure efficiency and purity.

Environmental Requirements

Climate: A hot, dry climate with consistent dry winds is essential.1
Evaporation Rate: The region must have a negative evaporation rate, meaning the amount of water lost to evaporation exceeds annual rainfall by at least 75 cm (about 30 inches).2
Precipitation: There must be minimal rainfall during the primary evaporating months.1
Geography: Large areas of flat land at or below sea level are required, with proximity to the sea and no risk of dilution from freshwater streams.1

Structural and Operational Requirements

Pond Infrastructure: Facilities require an almost impermeable soil base and dikes to retain the brine.1
System Design: A series of shallow ponds is used to transmit brine from the source, often utilizing pumps and canals to manage flow and elevation.12
Concentration Process: Seawater is moved through pre-concentration ponds to reach saturation before being transferred to crystallizing pans, where the salt precipitates out.12
Logistics: Inexpensive transportation or nearby markets are necessary for economic viability.1