"The climate has certainly changed, but this is scary!" Kuljanin, 68, told AFP near the lake's receding shores in southern Bosnia.

For years, the village of Ostrozac, where Kuljanin lives, had profited from the tourists attracted by Jablanicko's emerald waters.

But the rain has dried up this year and its water levels have plummeted.

Every year as the summer ends, water is gradually released from the 30-kilometer (18-mile) long lake so that the autumn rains can be absorbed.

"Its levels vary a little—it goes down and up. But now, I don't know what's going on," said Kuljanin, pointing to the beached boats far from the remaining sliver of water left in the area.

Bosnia may be one of Europe's poorest countries but it has long been rich in one resource: water.

The World Bank estimates Bosnia's resources of renewable fresh water at nearly 10 cubic meters (350 cubic feet) per person per year.

Some of Europe's most pristine rivers run through the country's rugged terrain, making it a paradise for rafters, kayakers and other outdoor enthusiasts.

But the lack of rainfall this year has changed the equation. "The drought has been truly catastrophic," Kuljanin said.

Further upstream, the lake has completely dried out.