For Immediate Release: June 20, 2018
Jorge Amselle: Jorge@saltinstitute.org
Park City, Utah— David Bloch, founder of the M. R. Bloch Salt Archive and a chemical engineering expert, says 3,000 years old underground aqueducts were used for irrigation and to produce purified salt. Bloch claims that the desert salt became one of the most valuable commodities traded along the legendary Silk Road. He discussed the importance of the Qanat- Karez- Falaj salt leaching system during his presentation at the 2018 World Salt Symposium in Park City, Utah today. The underground aqueducts were implemented in arid areas and used in places from Morocco to Afghanistan. Qanat is the Persian word for “channel,” while karez is the term used in Afghanistan and Central Asia.
Qanats are sloping underground tunnels and carry water from higher elevation ground water to lower elevation areas using gravity alone. These structures are serviced by a series of vertical shaft and help prevent evaporation, while delivering water long distances. Individual tunnels can stretch for 50 kilometers. More than 150,000 Qanat Karez sweet water distribution systems, including more than 200,000 kilometers of tunnels, are present in the desert communities of Central Asia. “The engineering and architecture rivals that of the Great Pyramid of Giza or the Great Wall of China,” said Bloch.
“The ancient Qanat Karez provided ‘surge flooding’ for short periods to desalinate the soil of the Sabkha basin. This produced leached salts in the form of a layered microbial salt crust, allowing the production of purified salt along the Middle Eastern section of the Silk Road, which supplied most of Europe with salt,” he added.
The Qanat Karez systems became vital in the period from 200 BCE to 300 CE, when worldwide coastal flooding caused the sea salt evaporation basins along the Mediterranean Sea and China coasts useless, and salt became catastrophically in short supply. “The conclusion is that desalination of the soil was primarily important for the production of pure layered slabs of salts and not for domestic and agricultural needs,” said Bloch.
The World Salt Symposium has been held periodically since 1962 and represents an international gathering of salt producers, researchers, journalists, business leaders and academics worldwide. It is the most comprehensive and important meeting on the subject of salt. The 2018 10th World Salt Symposium is being hosted by the Salt Institute.
The Salt Institute is a North American based non-profit trade association dedicated to advancing the many benefits of salt, particularly to ensure winter roadway safety, quality water and healthy nutrition.