How much desal is too much?
Israel is predicting an operational surplus of desalinated water as soon as next year. What are its options?
For over a decade, Israel has faced a shortage of water, forcing the country to utilise precious reserves from its aquifers and the Sea of Galilee. The situation has deteriorated dramatically over the past seven years due to an ongoing drought, leading to a cumulative deficit in the country’s renewable water resources of around 1.5 billion m3.
The situation now appears to be improving due to a growing dependence on desalinated water, and the Israeli Water Authority is predicting that the country will have an operational surplus starting in 2013. At the end of next year, Israel expects to be producing nearly 600 MCM/yr (1.64 million m3/d) of desalinated water.
“With the operation of all five coastal desalination plants, we are expecting a 150- 200 MCM/yr [411,000-548,000m3/d] operational surplus,” predicts Michael Zaide, head of strategic planning at the Israel Water Authority.
“The additional volumes of fresh water will be used to replenish the aquifers and the Sea of Galilee, which have in recent years reached dangerously low levels,” he told GWI. The actual annual extent of groundwater replenishment will depend on rain levels in the coming years; the current winter is likely to be the first since 2005 in which precipitation is in line with, or possibly even higher than historical averages.
Zaide said that over the next ten years, the Water Authority’s strategy is expected to allow for a ‘steady-state’ situation, whereby water supply and demand will be in sync. The authority’s calculations take into account a 1 to 2% annual increase in fresh water demand due to demographic growth, as well as greater volumes of water being transferred to Jordan and the Palestinian territories in future. At present, Israel supplies Jordan with 50 MCM/ yr (137,000m3/d) of water, while the Palestinian territories receive 55 MCM/yr (150,700m3/d).
Fresh water consumption in Israel is Isracurrently running at 1.4 BCM/yr (3.84 million m3/d), with total consumption at 2 BCM/yr (5.48 million m3/d; this figure includes reused water, as well as transfers to Jordan and the Palestinian territories).
The Israeli government has approved a 750 MCM/yr (2.05 million m3/d) target for desalinated water production in 2020, although Zaide said that the timetable for the roll-out of future desalination infrastructure will ultimately depend on demand.
The Water Authority’s master plan also calls for increasing the volume of treated sewage effluent from just under 400 MCM/yr (1.1 million m3/d) at present to 500 MCM/yr (1.37 million m3/d) in 2020. The additional volumes will be allocated to the country’s agricultural sector, which from 2014 is not expected to face annual cutbacks in water supplies, marking the end of decades of restrictions. “The issue is likely to be a shortage of land, and not water,” Zaide observed.