Home / General Knowledge / Human Water Use is Draining the World’s Saline Lakes

 

Via Ars Technica : Rising temperatures might not be helping, but overuse is the real problem.

Saline lakes, like the Caspian Sea, the Dead Sea, the Salton Sea, and of course the Great Salt Lake, have served as recreational playgrounds and tourist attractions, supported thriving fishing and shipping industries, and yielded minerals to be extracted for commercial and industrial applications. A slightly less quantifiable benefit they used to grant was providing habitats for waterbirds.

But these lakes are getting smaller and smaller—and becoming saltier and saltier—as we siphon off ever more of their water, predominantly for agricultural purposes. A perspective piece published in Nature Geoscience this week entitled “Decline of the world’s saline lakes” bemoans that “the ecosystem services provided by saline lakes are real, but less easily quantified [than the benefits of water consumption], and may have a constituency that is less well established in law, business, and social practice.”

The economic benefits of taking water from these lakes for agriculture is apparent, whereas the costs of doing so are not as obvious. But the costs are there. The lakes’ decreasing surface may render their shores inaccessible for mineral extraction. Their increasing salinity may cause the collapse of recreation, tourism, fisheries, and ecosystems, as the species that used to thrive in them can’t tolerate all that salt.

But perhaps the biggest problem is that as they become desiccated, they slough off fine dust particles that are bad for agriculture and cause a number of severe health problems, like asthma, lung infections, and other respiratory diseases. Each of these problems is currently playing out in Utah and near the Salton Sea in California. Utah’s Great Salt Lake is at its lowest level in recorded history—certainly since pioneers arrived from back East in their wagons in 1847. Over half of the water taken from the lake is used for agriculture.

Two tactics have been used to preserve saline lakes. One is to dam or dyke them to make them smaller, so the surface available for evaporation is better matched to the amount of water coming into the lake. This creates both a stable surface area and a stable level of salinity, both of which can be maintained. The other is to put more water into them, which is a tactic being debated for the Dead Sea.

This preservation work is often a hard sell, though, as communities want the water for agriculture. Little wonder it’s a hard sell, since those who benefit from preservation are predominantly waterbirds and brine shrimp. That kids with asthma also suffer needs to be a consideration, and a greater awareness of the harms of increased salination might shift the balance toward preservation.

 

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