In what could prove a diplomatic headache for Athens in years to come, Bulgarian officials have announced plans to divert the waters of the Nestos River, which irrigates large tracts of northern Greece before flowing into the northern Aegean. Scientists in northern Greece told Kathimerini they were informed of the project, which has not yet progressed beyond the stage of a tentative idea, during a recent meeting with Bulgarian colleagues in Sofia. The Nestos, which rises in the Rhodope Mountains in Bulgaria, courses through eastern Macedonia and western Thrace to debouch east of Kavala, opposite the island of Thasos in a delta that is a significant wildlife habitat. According to Yiannis Mylopoulos, professor of hydraulics and environmental engineering at the University of Thessaloniki, Bulgaria is bound by bilateral agreements to let 29 percent of the river waters flow into Greece. «But in practice, we actually get 75 percent of the waters, as our neighbors are unable to exploit the rest,» he said. «But what will happen if they develop the possibility of using the water? The 29 percent is by no means enough to cover irrigation needs and preserve the ecosystem.» If the diversion project – to irrigate parts of southern Bulgaria – materializes, Mylopoulos said, «the Drama plain will become parched and the Nestos delta wetland will suffer irreparable damage.» A related problem is caused by high pollution levels in the waters of the Axios, which flows through the Former Yugoslav Republic of Macedonia into northern Greece to debouch near Thessaloniki. According to Nikos Arvanitidis, head of the Institute for Geological and Mining Research, 500 tons of liquid waste, including high concentrations of lead, cadmium and other toxic metals, end up in the Thermaic Gulf every year.