Black Sea

     Black Sea is inland sea. It occupies an area of about 465,000 sq km, between SE Europe and Asia, It is 1,210 km from east to west, up to 560 km wide, and has a maximum depth of 2,245 m. Black Sea is connected with the Aegean Sea through the Bosporus, the Sea of Marmara, and the Dardanelles, and with the Sea of Azov by Kerch Strait. The Black Sea is enclosed by Ukraine on the north, Russia on the northeast, Georgia on the east, Turkey the south, and Bulgaria and Romania on the west. The total Black Sea coastline is 4090 km.
     The eastern Bulgarian coast is washed by the Black Sea. 380 km marvelous strech of beaches, calm and safe sea, clear water and healthy air, fine golden sand and natural dunes, mineral water springs, blue flag winning resorts, holiday villages and campsites.
     Average air temperature in the summer is about 28°C, water temperature - 25°C. There are more than 240 hours of sunshine in May and September and more than 300 hours in July and August. The two international airports of Varna and Bourgas connect the Bulgarian Riviera to the world.

Rivers

     The complex relief structure and the climate of Bulgaria do not create conditions for big rivers. The river network is relatively dense but unevenly distributed. Most of the rivers in Bulgaria spring from its high mountains and flow into the Black Sea (predominantly through the Danube River) and the Aegean Sea. The catchment basins of these rivers are small - the biggest one is the Maritsa River basin. There are 526 rivers in Bulgaria longer than 2,3 km. The longest one is the Iskar - 368 km.
     Length of the rivers in Bulgaria varies in the range of 100 - 300 km, the water level varies as well. With the highest level during the spring and early summer, most of the rivers' level goes very low in August-September. While their potential for power production is relatively low, most of them are used for irrigation.
     Danube is the only navigable river in Bulgaria. It flows along the northern part of the country covering 609 km of the Bulgarian northern boundary. The Danube is the second longest river in Europe behind Volga River and the only major European river to flow from West to East. It takes its source in the Black Forest Mountains of Germany, and empties after 2850 km (1770 mi) in the Black Sea on the Romanian coast. Along its way, the Danube flows through nine countries (Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Bulgaria, Romania, and Ukraine) and drains an area slightly larger than 817 000 km2, over more than a dozen countries. The Danube is an important transport link to the Central European countries and Russia and Ukraine, as well as main source of water for irrigation of the Danube Hilly Plain.
     The longest rivers on the territory of Bulgaria (in km): Iskar (368.0 km), Toundga (349.5 km), Maritsa (321.6 km), Osum (341.0 km), Struma (290.0 km), Yantra (285.5 km), Kamchiya (244.5 km), Arda (241.3 km), Louda Kamchiya (200.9 km) and Roussenski Lom (196.9 km).
     Struma River is the greatest river in the Western part of Bulgaria. Its catchment area is 10 800 sq.km. It takes its source from the Vitosha Mountain, runs first westward, then southward, enters the Greek territory at the Kulata village and flows into the Aegean Sea. The river's length to the border is 290 km. Its greater feeders are the Strumeshnitsa River, the Dragovishtitsa River, the Djerman, the Pirinska Bistritsa and the Rilska River.
     Iskar River is the longest river in Bulgaria. It springs from the Rila Mountains and does its way towards the Danube, crossing the Balkan Range, where it has formed an astounding 60 km gorge with plenty of meanders, precipices and caves. Its length is about 368 km., and its total water area is 8 646 km.
     Mesta River springs from the Rila Mountain (2716 m above sea level) in Southern Bulgaria and after approximately 230 km through the territories of Bulgaria and Greece, flows into Thracian Sea (White Sea), located east of the town of Cavalla (Greece). Its total catchment area is 5749 sq.m. 3437 sq.m. (60%) of the area belongs to Bulgaria, and the rest of it (2315 sq.m. or 40%) - to Greece. The Mesta River has as many as 25 tributaries: Dospatska River (the biggest tributary, which flows into Mesta on Greek territory), Bistritsa River, Kanina River, Matnitsa River, Breznishka River, Glazne River, Zlataritsa River, Dobrinishka River, Retije River and others. Its tributaries spring from the highest mountains in Bulgaria - the mountains of Rila, Pirin and Western Rhodopes.
     Arda River is the biggest river in the Rhodopes. It is a right tributary of the Maritsa River. Arda River flows from southwest to the northeast. Its length is about 241 km. and its water area is 10 797 sq. km.
     The merging of two small rivulets, springing from the eastern Balkan Range - Luda Kamchia and Golyama Kamchia, forms the Kamchia River. Running down through the Balkan Range it meanders through unique woodland called Longoza and flows into the Black Sea. The mouth of Kamchia River is one of the most beautiful sights of the Bulgarian Black Sea region.
     Maritsa River springs from Marichinite ezera in Rila Mountain and runs into the Aegean Sea. It is long 525 km., from which 322 km. are on Bulgarian territory. The river has about 100 tributaries. The river flows along one of the most beautiful and one of the most ancient towns on the Balkan Peninsula - Plovdiv.
     Osam is the name of a river in North Bulgaria, with a length of 314 km and a catchment area of 2 820 km. The river takes its source from the foot of the peak "Levski" in Stara Planina, at an altitude of 1821 m. The Osam flows into the river Danube near the town of Nikopol.
     Vit is a river in Northern Bulgaria with a length of 189 km. The source of Vit is in Stara Planina at an altitude of 2030 m and it is draining in Danube.

Lakes

     The high-mountain lakes in Bulgaria add to about 400 in number. Glacial lakes are most numerous.
     There are about 190 glacial lakes in the Rila Mountains. Their depth varies between three and 40 meters.
     The circus of "Seven Rila lakes" is the most beautiful one in Bulgaria. It is situated in the northwestern part of the marvelous Rila Mountain. The lakes are located in tiers. To the central part of the circus picturesque landscapes of green meadows with fragrant flowers and forests of dwarf pines and juniper can be seen and higher great steep rocks surround the lakes. The Rila lakes bear the following names: Salzata (The Tear), Okoto (The Eye), Babreka (The Kidney), Bliznaka (The Twins), Botanicheskoto or Trilistnika (The Botanical), Ribnoto (The Fish lake), and Dolnoto.
     Strashnoto Lake is settled in Rila Mountain. At its north slope is located the Strashnoto lake shelter. The lake is located at the foot of the Kupenite and Popova kapa peaks at about 2465 meters above the sea level.

     The Pirin Mountains boast about 158-164 lakes, covering an area of 180 hectares. The larger lake groups include:
     Banderishki Lakes are a group of twelve glacier's lakes, which are located in the Northern Pirin Mountain. They are situated in the Banderishki circus. The group includes also the Ovshnati Lakes. The altitude of the lakes is between 2190 m and 2345 m above sea level. Its geological base is formed by granite. The total area of the lakes is 126.7 decares. During July the temperature of the water reaches 10о-12оC. The water is low mineralized - it contains sodium and chloric ions. The lakes flow away to the Banderitsa River.
     Pleski Lakes are a group of four permanent lakes and one temporary, which are located in the northern part of the Pirin Mountain. They are situated in the Pleshki circus at an average altitude of 2200 m above sea level. The lakes have glacial origin and their base is formed by granite. The temperature of the water during the summer is 11o-14oC. The water is low mineralized -contains mainly hydro-carbonated and sodium ions. The Pleshki Lakes host trout and American Brook Char populations. They drain into Pleshka River, which is a left tributary of Dissilitsa River.
     Spanopolski Lakes are a group of nine permanent and two temporary lakes, which are located in the central part of the Northern Pirin Mountain. Eight of the permanent lakes are situated in the circus of Golyamo (Big) Spano pole and one of them - in the circus of Malko (Small) Spano pole. Their average altitude is 2350 m above sea level. They have glacial origin. The geological base of the lakes is formed by granite. The temperature of the water during the summer is 10o-12oC. The water is low mineralized - mainly hydro-carbonated ions. The Spanopolski Lakes host trout populations. They give the beginning of the Spanopolska River (Sarchaliitsa River) and Malka (Small) Spanopolska River (Malka Sarchaliitsa River).
     Prevalski Lakes (Demyanishki Lakes) are a group of four lakes in the northern part of the Pirin Mountain. They are situated in the Prevalski circus at 2330 m above sea level, with a total area of 32.5 decares. The lakes have glacial origin. Their geological base is formed by granite. The temperature of the water during the summer is 11o-14oC. The water is low mineralized - it contains mainly hydro-carbonated and sodium ions. They drain away into one another and through the short Prevalski stream flow into the Valyavitsa River.
     Bezbojki Lakes are a group of four lakes with glacial origin, which are located in the northern part of the Pirin Mountain. One of the lakes is permanent and the others are temporary. The lakes are situated in the Bezbojki circus at average altitude of 2400 m above sea level. They are formed by granite.
     Georgiiski Lakes are a group of four lakes, which are located in the northern part of the Pirin Mountain. They are situated terrace-like in the Georgiiski circus to the west of the peak of Malak Vihren (the Muratov peak). The lakes have glacial origin and are formed by granite. Their total area is 73.7 decares. The temperature of the water is 12o-13oC during the summer. The water is low mineralized (hydro-carbonated, sodium and chloric ions). The lakes host Balkan trout and American Brook Char populations. They drain into the Georgiiska river, which is a left tributary of the Vlahinska river.
     Valiavishki Lakes are group of about 15 lakes in the northern part of the Pirin Mountain, located terrace-like in the Valiavishki circus. They have a glacial origin and granite base. Their average altitude is from 2295 m to 2472 m above sea level. The water temperature reaches 13o-18oC during the summer and it has low mineral content - mainly chloric and hydro-carbonated ions. The lakes host brown trout and American Brook Char populations. They drain through one another and give rise to the Valiavitsa River, which is a tributary of the Demianitza River. Its shores are steep and rocky, overgrown with dwarf pine.
     Popovi Lakes (Papazgyolski Lakes in the past) are the biggest group of lakes in the Northern Pirin Mountain. The group consists of twenty-two permanent lakes and three or four temporary ones. It includes the lakes, which are situated in the circus of Popovi Lakes (the Papazgyolski circus) - the Popovo Lake, the Samodivski Lakes, the Polejanski Lakes, the Banski Lakes and these, which are located along the upper course of Retije river. The average altitude of the lakes is 2200 m above sea level. They have glacial origin. Their geological base is formed by granite. The temperature of the water during the summer is 11o-14oC. The water contains mainly hydro-carbonated and sodium ions (14.2 mg/l in the Popovo Lake). The lakes host trout populations. They drain into the Retije River.

     In the heart of the Rhodopes mountain are located the Smolian lakes. Many years ago the number of the lakes was twenty, but nowadays only seven have survived. The weather heaped up soils and stones, and therefore some of them were covered up. The lakes are located picturesquely on several terraces. Wonderful pine forest surrounds the lakes and makes them more impressive. The natural phenomenon Orlovi Skali (Eagle's Rocks) rises in the vicinity.
     Chirski lakes (7 in number) are situated 1600 meters above the sea level in a picturesque place with the same name in the Western Rhodopes, 27 km. from the village of Trigrad. They are natural landslide lakes formed by melting glaciers during the Ice Age. On of them is called Magicheskoto ezero (The Magic Lake). Folded in mist and vapours, surrounded by odd trees it looks like a mysterious fairy tale lake. It is told to be a home of beautiful wood-nymphs, who enchant the shepherds with their melodic songs and marvelous dances. The lakes are extremely beautiful with a crystal mountain water, where trout swims. They are surrounded by over 2000 decare of vast meadows, covered with colourful flowers in spring, high grass - green in summer, red, yellow and brown in autumn and white snow in winter.

     The natural lakes in Bulgaria are comparatively few. The biggest are along the Black Sea coast - the lagoon lakes of Alepou, Arkoutino, Pomorie, and the firth lakes of Beloslav, Bourgas, Varna, Shabla.
     Bourgas Lake is an open firth (known also as Vaya lake) of roughly oval shape with maximum length of 9.6 km, maximum width of 4.5 km. and a surface area of 2760 ha. Its depth at places reaches 1.3 m. Thus the Bourgas lake is on the first place rated by size among the natural lakes in Bulgaria. It is separated from the sea by an extensive sand bar where the industrial sector of the town has been built on. Today the Bourgas Lake is linked with the sea by a channel ending with a sluice. The rivulets Aitoska, Sandardere and Chukarska flow at the lake's western part. There are insignificant seasonal and annual fluctuations of the lake's water level.
     A rich plant and animal life is a typical feature of the Bourgas Lake. It is surrounded by a ring of reed growth which forms a very large bed in the westernmost part. More than 60 species of invertebrate have been found there along with over 20 fish species. So far 254 bird species have been recorded on and around the Vaya. Many of them are rare for Bulgaria or for Europe and 9 of them are among the globally threatened species. Some of the birds like Herons, Cormorants, Black-winged Stilts, Grebes breed there, while other species, mostly Ducks, Geese, Pelicans and Swans spend the winter or roost during migration. This was the main reason to put the lake in the European IBAs List.
     Pomorie Lake is the northernmost of all Bourgas lakes. It is a hyperhaline naturally formed lagoon and is situated in closest vicinity to the town of Pomorie, separated from the sea by a sand bar and a manmade dike. There is a canal in its southern part connecting the lake with the Black sea. The lake surface area is 850 ha but together with the surrounding wetlands adds up to about 1000 ha. Its shape is one of the elongated oval the length of it along the long axis being 6.7 km and the average width being about 2 km. In the southern part of the lake medicinal mud is excavated while its northern part has been turned into salt works.
     The lake's water great salinity has determined the presence of specific plant and animal species: Glasswort, Sea Wormwood, Sea Blite, Caucasian Goby (a species of fish that can stand up to 80 promils water salinity), the Brine Shrimp (Artemia salina - an important component of the birds diet). Some rare plants listed in Bulgaria's Red Book like the Black Sea Campion, the Water Lily (Nymphaea alba), and others also occur there.

     The lakes and the swamps along the Danube have been drained with the exception of Sreburna Lake which has the status of a natural protected zone. Located 16 km west of the town of Silistra, Sreburna is a fresh-water lake extending over an area of 600 hectares that has been declared a biospheric reserve. About 100 different kinds of migratory birds nest here, including some disappearing ones like the Dalmatian pelican, cormoran, ibis, mute swan, egret and heron. About 21 species of amphibians and reptiles live in the wetland. Special monitors have been installed among the thick reeds for undisturbed wildlife observation.

     Numerous dams have been built as parts of hydrosystems and hydrojunctions - Iskar, Arda, the Batak Hydropower System, Dospat-Vucha, Belmeken-Sestrimo. About 2000 smaller dams were built, mostly for local irrigation purposes.

Mineral Waters

     Due to its geological structure Bulgaria is very rich of mineral waters. There are more than 1000 springs of varying temperatures and chemical composition, with a total output of 400 million liters per day.
     The last ten years have seen a rapid growth in the production of bottled mineral water. Currently Bulgaria exports 10 million liters of superior quality water per year to the United States, Germany, Holland, Romania and Greece.
     The curative qualities of Bulgaria's mineral waters have been known since Roman times. Waters rich in sulphate are great for the liver and the gall bladder; salty mineralized waters are best for the treatment of orthopaedic, neurological and gynaecological diseases; other types of drinking water are good for the kidneys and the urinary tract.
     A number of Bulgaria's spa resorts are built in areas of former Thracian or Roman settlements - Sandanski, Hisarya, Velingrad, Sapareva Banya, Kyustendil. After a decline in the last decade, the infrastructure for spa tourism is improving.