Hydrography

Bulgaria has a dense network of about 540 rivers, but with the notable exception of the Danube, most have short lengths and low water-level.

Most rivers flow through mountainous areas; fewer in the Danubian Plain, Upper Thracian Plain and especially Dobrudzha. Two catchment basins exist: the Black Sea (57% of the territory and 42% of the rivers) and the Aegean Sea (43% of the territory and 58% of the rivers) basins. The longest river located solely in Bulgarian territory, the Iskar, has a length of 368 km. Other major rivers include the Struma and the Maritsa River in the south.

Rila and Pirin feature around 260 glacial lakes; the country also has several large lakes on the Black Sea coast and more than 2,200 dam lakes. Many mineral springs exist, located mainly in the south-western and central parts of the country along the faults between the mountains.

The Bulgarian word for spa, баня, transliterated as banya, appears in some of the names of more than 50 spa towns and resorts including Sapareva Banya, Hisarya, Sandanski, Bankya, Varshets, Pavel Banya, Devin, Velingrad and many others.

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