Drop in the level of the river's waters means that nuclear reactor may have to close down

In Cernavoda, a small town in southeast Romania, social housing projects stretch all along the left bank of the Danube. The now dilapidated buildings sprang up in the 1970s and 1980s, after the dictator Nicolae Ceausescu decided to build the country's first nuclear power plant there.

In his ambition for power and prosperity, he also ordered a canal to be built from Cernavoda to Constantza, a port on the Black Sea, to shorten the trade route by 400km. The excavations were done by thousands of political prisoners, many of whom died.

Today, 21 years after the fall of communism, the threat to Cernavoda is not from dictatorship but the drought that has hit Romania since August. "Look at the water level," said Vasile Mogos, who lives in a council flat by the river. "I would never have imagined that the Danube could fall so low."

The Danube crosses Europe from west to east over 2,850km, from its source in Germany's Black Forest to the Black Sea in Romania. In its path Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Bulgaria and Romania all exploit the waters of Europe's second-longest river after the Volga.

The first reactor in the Romanian nuclear power plant, which uses Canadian CANDU reactor technology based on natural uranium and pressurised heavy water, came on stream in 1996. A second reactor was built in 2007, and three others are planned, since the Romanian government counts on nuclear power for energy self-sufficiency.

The two reactors in the Cernavoda plant generate 20% of those needs and were built on the banks of the Danube to use its waters for cooling.

Early this month, the Danube's flow rate in Turnu-Severin, a town in southwest Romania, home to the country's largest hydroelectric power plant, was 2,400 cubic metres per second, 63% of the usual average of 3,800 cubic metres per second. Hidroelectrica, the public corporation in charge of delivering the energy produced by the plant, is generating only 1,800MW instead of the usual 2,100 MW.

In 2003 the drought in Romania was so severe that it led to the shutdown of one of the Cernavoda reactors. Cantemir Ciurea, director of the National Committee for Controlling Nuclear Activities, said: "We immediately put in place a new system that allowed the pumps to extract the cooling water from much lower levels."

The Romanian authorities have not, however, discounted the possible closure of a reactor if the drought persists.

The lack of rain is also worrying for hotel owners in the Danube delta, who have lost some 10,000 tourists this year, with 250 boats and craft stranded, waiting for the rains before they can sail again. Losses are now counted in millions of euros.

Second world war battleships have even resurfaced on the Sava river, a tributary that joins the Danube in Belgrade, Serbia.

The drought is also threatening the fragile ecosystem. According to the World Wildlife Fund (WWF), the race to expand agricultural land in the 20th century has already eliminated 80% of the Danube's wetlands.

"The wetlands along the riverbanks were able to absorb water in the event of flooding and free it in periods of drought," explained Andreas Beckmann, director of WWF's Danube-Carpathian programme. "We are going to see more and more of these extreme situations. Our best response is to protect and strengthen our green infrastructure."

This article originally appeared in Le Monde