The Economist December 1st 2018

Walking on desalinated water

Can a biblical body of water be saved?

The WATER level of he sea of Galilee on which Jesus supposedly walked, is a national obsession in Israel. Newspapers report its rise and fall next to the weather forecast. Lately the sea, which is actually a freshwater lake, has been falling. It is now a quarter empty. Small islands have emerged above its shrinking surface. If Jesus were to return today, he'd have a much easier time.

For the past five years Israel has experienced its worst drought in nearly a century. That has reduced the flow of the Jordan river and other streams that feed into the Sea of Galilee. Less turnover in the lake's water is leading to increased salinity and the spread of cyanobacteria (sometimes called "blue-green algae", despite not being algae). As the pressure from fresh water eases, it allows in more salt water from subterranean streams. Climate change is expected to exacerbate these problems, perhaps one day making the lake water undrinkable.

Israel can probably cope. For most of its history the Sea of Galilee was its largest source of drinking water. But over the past decade the country has invested heavily in desalination plants and projects that allow it to reclaim effluents and brackish water. Since 2016 well over half of the water consumed by households, farms and industry has been "man-made". Less than 70m cubic metres of water will be pumped out of the Sea of Galilee this year for consumption, down from 400m in the past. Some 50m will go to Jordan, which is also suffering from a severe drought.

Though it is no longer a vital water source, few want to see the lake run dry. People in the city of Tiberias and dozens of smaller communities eat and sell its fish. More importantly, its religious significance attracts thousands  of Israeli tourists and Christian pilgrims each year.

So in June the government authorised a billion-shekel ($270111) plan to pump desalinated sea water, mostly from the Mediterranean, into the Sea of Galilee. Work on a new pipeline began last month. A freshwater lake has never been replenished in this way, but the scientists monitoring the plan believe it will work similarly to rainfall and will not harm the lake's unique ecosystem.

By 2020 the new pipeline is expected to pump enough desalinated water into the Sea of Galilee to stabilise its level. But Yuval Steinitz, the energy minister, wants to go further. His ministry is preparing plans for larger desalination plants, which would double Israel's current output of nearly 600m cubic metres of desalinated water. The surplus would go to refill the lake, providing Israel with a strategic store of water, says Mr Steinitz, in case the desalination plants are hit by earthquakes or war.

Jesus impersonators should take advantage while they still can.