Persistent drought across much of Spain has seen reservoir water reserves slide this month to 45.3 percent of capacity, according to figures which the Environment Ministry published Tuesday.
This week's figure, equivalent to 24,108 cubic hectometres (95,000 cubic feet), was 1.5 percent down on a week earlier to fall below that of the same stage last summer, which was marked by Spain's worst drought since 1947.
The fall came only six days after the government warned persistent drought across much of Spain this year may threaten supplies of drinking water to some two million people in the south of the country within weeks.
Reserves in the region around the River Segura are under the greatest threat having fallen to a mere 13.3 percent of capacity. Further north, around the River Tagus, ministry figures show water levels at 44.8 percent of capacity.
Spanish regional authorities periodically allow suppliers to dip into the Tagus reserves to make up for the common summer slide in the Segura region.
The Buendia and Entrepenas dams, where the transfer begins, last week contained 265 cubic hectometres of water, perilously close to the legal limit of 240 cubic hectometres below which supply transfers are not permitted under Spanish environmental laws.
Environment Minister Cristina Narbona said last week in recognition of the seriousness of the situation that the government was mulling emergency measures, including the early opening of a desalination plant and drilling new wells in the affected regions.
In northern Spain the situation is less urgent with reserves standing at between 58 percent and 71.5 percent of capacity.
