Salt evaporation pond in Manaure, La Guajira, Colombia

A salt evaporation pond is a shallow artificial salt pan designed to extract salts from sea water or other brines. The salt pans are shallow and expansive, allowing sunlight to penetrate and reach the seawater. Natural salt pans are formed through geologic processes, where evaporating water leaves behind salt deposits. Some salt evaporation ponds are only slightly modified from their natural version, such as the ponds on Great Inagua in the Bahamas, or the ponds in Jasiira, a few kilometres south of Mogadishu, where seawater is trapped and left to evaporate in the sun.

During the process of salt winning, seawater or brine is fed into artificially created ponds from which water is drawn out by evaporation, allowing the salt to be subsequently harvested.[1]: 517 [2]

The ponds also provide a productive resting and feeding ground for many species of waterbirds, which may include endangered species.[3] However, Ghanaian fisheries scientist RoseEmma Mamaa Entsua-Mensah also noted that salt winning can destroy mangrove forests and mudflats, altering the environment and making it unproductive for other development or fish growth.[4] The ponds are commonly separated by levees. Salt evaporation ponds may also be called salterns, salt works or salt pans.

Algae and color

San Francisco Bay salt ponds

Due to variable algal concentrations, vivid colors (from pale green to bright red) are created in the evaporation ponds. The color indicates the salinity of the ponds. Microorganisms change their hues as the salinity of the pond increases. In low- to mid-salinity ponds, green algae such as Dunaliella salina are predominant, although these algae can also take on an orange hue. Halobacteria, a type of halophilic Archaea (also known as Haloarchaea), are responsible for changing the color of middle to high-salinity ponds to shades of pink, red, and orange. Other bacteria such as Stichococcus also contribute tints.[citation needed]


Notable salt ponds include:

Until World War II, salt was extracted from sea water in a unique way in Egypt near Alexandria.[11] Posts were set out on the salt pans and covered with several feet of sea water. In time the sea water evaporated, leaving the salt behind on the post, where it was easier to harvest.


Main articles: Open-pan salt making and Saltern

Salt pans are shallow open, often metal, pans used to evaporate brine. They are usually found close to the source of the salt. For example, pans used in the solar evaporation of salt from sea water are usually found on the coast, while those used to extract salt from solution-mined brine will be found near to the brine shaft. In this case, extra heat is often provided by lighting fires underneath.


See also


  1. ^ Davies-Vollum, K. Siân; Wes, Matthew (August 2015). "Shoreline Change and Sea Level Rise at the Muni-Pomadze Coastal Wetland (Ramsar Site), Ghana". Journal of Coastal Conservation. 19 (4). Heidelberg, Germany: Springer Science & Business Media: 515–525. doi:10.1007/s11852-015-0403-y. ISSN 1400-0350. OCLC 5889482841. Retrieved 27 February 2024.
  2. ^ Morrison, Philip (November 1978). "Books: The History of Salt, the Rise of the 'Chip' and How the Indians Lost Faith in Their Game". Scientific American. 239 (5). New York, New York: Scientific American, Inc.: 35–36. ISSN 0036-8733. OCLC 9986402667. Retrieved 27 February 2024.
  3. ^ Athearn, Nicole D.; Takekawa, John Y.; and Shinn, Joel M. (2009) Avian response to early tidal salt marsh restoration at former commercial salt evaporation ponds in San Francisco Bay, California, USA, Natural Resources and Environmental Issues: Vol. 15, Article 14.
  4. ^ Ashon, Enimil (10 March 2017). "The Woman Who Saw Tomorrow". The Graphic. Accra, Ghana. Archived from the original on 25 February 2024. Retrieved 27 February 2024.
  5. ^ Napa Salt Pond Complex Archived 2011-08-19 at the Wayback Machine, The Bay Institute
  6. ^ Salt ponds, South San Francisco Bay, NASA Earth Observatory
  7. ^ "NASA Helps Reclaim 15,100 Acres Of San Francisco Bay Salt Ponds". Space Daily. Moffett Field. July 14, 2003.
  8. ^ "Cargill Salt - San Francisco Bay". Archived from the original on 2011-08-07. Retrieved 2011-08-09.
  9. ^ "The Salt Works". 19 July 2011.
  10. ^ "Baleni Cultural Camp". African Ivory Route. Transfrontier Parks Destinations. Retrieved 11 September 2019.
  11. ^ Salt, Grown On Sticks Harvested From Sea, Popular Science, March 1933