Caspian Water Transfer Unwise

The plan to transfer water from Caspian Sea in the north to the drought-stricken Semnan Province will cost the country's ecosystem dear, environment experts say.

Inter-basin transfer or trans-basin diversion refers to manmade conveyance schemes that move water from one basin to another where water is scarce, usually for development purposes.

The transfer of desalinated water from Caspian Sea to the country's central plateau was first proposed by American experts in the 1960s. Since then, the plan has undergone changes and now the authorities are considering its implementation to supply water to Semnan.  

The plan involves siphoning some 7,000 liters of water out of the sea per second to be transferred to Semnan after desalination, Mehr News Agency reported.

Naghmeh Mobarqaei, an expert on environmental studies at Shahid Beheshti University, has criticized the project for increasing "the Caspian salinity and seriously harming marine ecosystems".

Desalination extracts mineral components from saline water, but it also produces large quantities of brine, possibly at temperatures above the ambient, which contains residues of pretreatment and cleaning chemicals.

Experts say brine is denser than seawater and therefore sinks to the bottom of water body, directly harming the ecosystem.

The plan is to be implemented through a technology known as reverse osmosis that will need a large number of carbon filters.

"They need to change filters frequently, producing a huge volume of waste," Mobarqaei said.

The other contentious issue is the path through which the pipeline would reach Semnan.

According to Mobarqaei, the 200-kilometer pipeline would have to pass through the Hyrcanian Forest, requiring the felling of trees in the ecologically-rich but vulnerable woodlands.

Besides, water will have to be pumped upward from 21 meters below sea level to the height of 2,000 meters.

"The pumping equipment would require at least 350 megawatts of power, equal to one-third of the output of Bushehr Nuclear Power Plant," Mobarqaei said.

The Caspian Sea’s legal status further complicates the water transfer project, as it is bordered by Iran, Russia, Azerbaijan, Kazakhstan and Turkmenistan.

"If Iran siphons water from the sea, the other four countries might do the same one day, and this would take a heavy toll on the body of water," the expert said.

-- Proposed Alternatives

Critics say there are more feasible and lasting solutions to the province’s water woes.

Rainwater harvesting, judicious water use (especially in the agricultural sector), promoting advanced  irrigation techniques, recycling wastewater, separating potable water from wastewater and implementing watershed plans are among measures suggested by experts.

Mobarqaei suggested that the modernization of irrigation systems in 1 million hectares of farmlands throughout the country, for instance, would require 3 trillion rials ($ 67 million) to help curb water scarcity in the province.

"The proposed water supply plan appears to be more harmful than helpful and the authorities should carefully evaluate the consequences before taking any hasty action," she said.