SANAA Gentle showers temporarily damp the dust and cool the August heat of Sanaa, but cannot remedy a grim water outlook for the Yemeni capital's 2 million people.
Some residents receive piped city water only once every nine days and others get none at all. The sinking water table means the municipality can now operate only 80 of its 180 wells, said Naji Abu Hatim, a Yemeni expert at the World Bank.
"People don't believe the magnitude of the problem. They see a little cloud and say, 'oh, God is still there, he can give us water'," he added. "But water is Yemen's number one problem."
That might seem a startling claim given that the country is also grappling with a tribal revolt in the north, violent unrest in the south, al Qaeda militancy and widespread poverty.
But water shortages in the southern city of Aden are already fuelling violence. One person was shot dead and three were wounded, two of them police, during water protests on August 24.
And fast-depleting aquifers make Yemen's plight the starkest in a desperately water-scarce region. Local disputes over water rights may turn violent, especially in tribal areas. Competition for supplies between cities and the countryside may sharpen.
"Yemen's water share per capita is under 100 cubic meters a year, compared to the water poverty line of 1,000 cubic meters," said Hosny Khordagui, Cairo-based head of the U.N. Development Program's water governance program in Arab countries.
Arab states, except Egypt, Iraq and Lebanon, all fall short of the water poverty line and the regional trend, blamed on climate change, is toward consistently lower rainfall.
Unlike wealthy Gulf oil states, Yemen, the Arab world's poorest country, is ill-placed to fill the gap between supply and demand with desalination. "They are thinking of it, but economically I very much doubt they can do it," Khordagui said.
Desalinating seawater and pumping it 2,000 meters uphill to the inland capital would be hugely expensive. Water could be transferred to Sanaa from another basin, but this might spark conflict with nearby provinces that are also parched.
"One idea, which is politically unacceptable, is to move the capital elsewhere. I don't see it happening," Khordagui said.
Sanaa, 50 years ago a sleepy, walled town of perhaps 50,000, is among the world's fastest-growing cities, with a population exploding at an estimated 8 percent a year, according to the World Bank, of which 5 percent is due to rural migration.
Water scarcity is forcing many poorer villagers to sell up and move to Yemen's cities, where few have the skills to thrive, even though they are expected to send money home to relatives.
From the 1970s, Yemenis turned swiftly from rain-fed farming to irrigation using water pumped from new tube wells, encouraged by the government and foreign donors keen to expand production.
"Finally they found irrigated agriculture was unsustainable because of the depletion of groundwater," Abu Hatim said.
Agriculture sucks up more than 90 percent of water used and a third of that goes to irrigate fields of qat, a mild narcotic intrinsic to the daily social life of most Yemenis.
Mismanagement of water resources is one reason why Yemen's plight is worse than that of neighbors such as Oman, argues Jac van der Gun, director of the International Groundwater Resources Assessment Center in The Netherlands.
Both countries have dwindling oil resources, but Oman's oil wealth is shared among only three million, compared to Yemen's population of 23 million, which is set to double in 20 years.
"Oman is a positive example of stability and charismatic leadership, so it is much easier for them to control their water problems. Yemen is not anarchic, but it comes close," he said.
Van der Gun cited the troubled northern province of Saada, the bastion of Shi'ite tribesmen whose intermittent rebellion against the government flared into fierce battles this month.
"Saada has a huge water problem, but they can't think about the future because they are thinking about today," he added.
Despite the afternoon downpours in Sanaa, Yemen's northern highlands have been suffering a two-year drought.
"The rains this year have been poor and late," said Ramon Scoble, a water expert for the German development agency GTZ who works in Amran province, just north of the capital.
"Rural sectors of north Yemen may face famine," he said, echoing a warning sounded in June by Abdul-Karim al-Iryani, senior political adviser to President Ali Abdullah Saleh.
"They won't be producing their own foodstuffs for another year and they won't have harvested enough seed to be able to grow again next year," Scoble said.
The government, backed by foreign donors, began applying a comprehensive strategy for water resources, irrigation, water supply, the environment and capacity building in 2005.
But experts describe implementation as patchy. The World Bank's Abu Hatim said the program was a palliative measure.
"It will not solve the problems, only alleviate them to buy time. The catastrophe is coming, but we don't know when."
(Editing by Jon Hemming)