The project area covers three important cross-border natural areas - the Arda and Mesta rivers and the Rhodope Mountains.

  • The Arda river basin

The Arda River is the largest river in the Rhodopes and the second largest tributary of the Maritsa after the Tundzha. The Arda River originates from the Ardabashi karst spring, located at the northern foot of Ardin peak (1730 m), at 1455 m above sea level. The spring is located 900 m northeast of the peak and 1.5 km south of the village of Gorna Arda. Municipality of Smolyan.

Boundaries and area

From the south the catchment area of ​​the river is formed by the border passing along the watershed with the rivers in Greece: Sushitsa and Filiuri, flowing directly into the White Sea and the Devil's River - a tributary of the Mesta River. To the west, the catchment area borders the rivers Tenes Dere and Shirokolashka - tributaries of the Vacha River. To the north are the rivers Chepelarska, Chinar Dere, Mechka, Kayakliyska, Harmanliyska and Biserska - all tributaries of the Maritsa River. To the east is the border with Greece and small tributaries of the Maritsa River.

The catchment area of ​​the Arda River up to the border is 5,273 km2.

The basin of the Arda River occupies the eastern part of the Rhodopes. Here the mountain gradually descends from west to east, as the Arda River with its tributaries flows between two main watersheds: one - the northern, called the Northeastern Rhodopes, which begins with G. Perelik (2191 m) and divides the river valley. Arda from the Maritsa River. The other - the southern chain, called the Southeastern Rhodopes, also begins with the Golyam Perelik newspaper. In the extreme eastern part between Krumovgrad and Ivaylovgrad there is an intermediate branch, which separates the valley of the river Arda from that of the White River.

The valley of the Arda River between the watersheds is filled with many hills and coupe-like heights, which have different directions and positions with each other. The Ardin Valley and the Eastern Rhodopes in general, as a strongly and intricately divided mountain, have quite valley extensions in the form of valleys along the rivers. These are: at the beginning of Arda the valley of the village of Smolyan, then the very large Kardzhali valley, to the east of it is Shiroko Pole, and even further alternate several insignificant valleys.


The Arda river basin was one of the best forested in all of Bulgaria. However, as a result of their unplanned use in the past and their reckless exploitation, much of the forest has been cut down, leaving large areas now deforested or covered with weak, stagnant forests.

About 40% of the total catchment area is occupied by low-stemmed and coniferous forests. Low-stemmed forests have a dominant influence. Coniferous forests are concentrated in the southeastern parts of the Central Rhodopes, while low-stemmed forests are scattered throughout the rest of the valley, mainly in the border areas and the lower reaches of the Arda River. The upper reaches of the Arda River are relatively sparsely forested. Coniferous forests and partly low-stemmed ones predominate here. The Arda River is the least forested in the middle reaches, where there are only a few small jagged forests.

  • The Mesta river basin

The basin of the Mesta River on the Bulgarian territory is limited to the south of the state border with the Republic of Greece; to the west of the catchment area of ​​the river Struma; north of the basins of the rivers Iskar and Maritsa; east of the Dospat river basin. The river is cross-border and flows into the Aegean Sea on Greek territory.

The Mesta River is formed by the confluence of the White and Black Places above the town of Yakoruda. The source of the river is considered to be the source of its right tributary Bela Mesta at an elevation of 2240 m above sea level above Lake Granchar from the group of Pottery Lakes in Eastern Rila. Initially, the Mesta River flows in a southwesterly direction, taking a southeasterly direction near Razlog and leaving the country at an elevation of 388 m.

The catchment area of ​​the Mesta river basin near the border with the Republic of Greece is 2,785 km2. The length of the Mesta River is 126 km. The Mesta river valley is the highest in the country with an average altitude of 1318 m.

The forests in the Mesta valley occupy about 49% of its catchment area. They are located in the mountain belt up to about 2000 m above sea level. Of these, 68% are coniferous, 26% low-stemmed and other beech. Mesta is the only valley in Bulgaria with such a wide distribution of White and Black Fir (Pinus peuce and Pinus heldreichii).

The Mesta river basin covers the southern slopes of Rila, the eastern slopes of Pirin and the western slopes of the Western Rhodopes. The three mountains are connected respectively by the Predel saddle (Rila and Pirin) and the saddle of Avramovi kolibi (Rila with the Rhodopes).

The river valley Places in climatic terms are characterized by great diversity. In the upper course, temperate-continental climatic conditions prevail, in the middle - transitional conditions, inland in the catchment area tending to the Mediterranean climate. The open valley in the south allows free invasion of Mediterranean climatic influence, ie. the middle and lower reaches fall into the southern Bulgarian subregion of the continental-Mediterranean climate area.

  • Rhodope Mountains

The Rhodopes occupy the eastern part of the Rila-Rhodope massif, in the central part of the Balkan Peninsula. The mountain stretches over the territory of Southern Bulgaria (parts of the districts of Blagoevgrad, Pazardzhik, Plovdiv and Haskovo and entirely of the districts of Smolyan and Kardzhali) and Northern Greece as pr

On the territory of Bulgaria the Rhodopes cover an area of ​​14,737 km2, which represents 81.88% of its entire territory. The mountain is divided into two parts - Western (high) and Eastern Rhodope (low). The average altitude of the Rhodopes is 785 m, and the western one is significantly higher than the eastern one. The highest peak in the Rhodopes is Golyam Perelik - 2191 m. The western border of the Rhodope Mountains with Rila, passes along the Yadenitsa River, crosses the Yundola Saddle and the Avramova Saddle and reaches the valley of the Mesta River. To the north the mountain borders the Upper Thracian lowland. The border between the western and eastern Rhodopes passes along the valley of the river Kayakliyka, the saddle Kitka and the valleys of the rivers Gorna Arda and its right tributary the river Madanska. The southern border of the Rhodopes unnaturally ends at the state border with Greece.

The location of the Rhodopes in the southeastern part of the Balkan Peninsula largely determines the climate. It is characterized as transient, as it is influenced by the northern colder air masses and the warm breeze of the Mediterranean. The average annual temperature of the Eastern Rhodopes is higher and more stable and ranges around 12-13 ° C. In the Western Rhodopes, under the influence of higher altitude, the average annual temperature varies from 5 to 9 ° C. The transitional nature of the climate in the Rhodopes is evident from the annual course of precipitation. In December in the Eastern Rhodopes is the maximum rainfall, and in August - the minimum. In the Western Rhodopes, on the other hand, summer rainfall predominates.

The Rhodopes are the largest accumulator of water resources in our country. Several large hydropower systems have been built here - Batashka, Ardinska and Vachinska. The regulated water outflow of the rivers is used for electric extraction, irrigation and stocking of the dam lakes. The whole mountain is cut by a densely developed river network with different directions. The drainage of the Rhodopes is entirely to the Aegean basin through three separate hydrographic systems: to the north - the river Maritsa, to the east - the river Arda, and to the south - the river Mesta.

The richness of the flora and fauna in the Rhodopes is largely due to their soil and climatic diversity. In terms of vegetation, the mountain is divided into two large areas. The Western Rhodopes are covered by a large plant area, which covers part of Rila. The Central European plant group is represented here, the most common being Spruce / Picea spp./ and White Pine / Pinus sylvestris /. The Eastern Rhodopes, which are under the influence of the Mediterranean climate, stand out as an independent plant sub-region, characterized mainly by its small population. In some places there are low-stemmed forests and shrubs, and in others - oak / Quercus spp./ and beech forests / Fagus spp./. Here reach the northern borders of some typical Mediterranean plant species, such as Jasmine / Jasminum spp./, Hairy Oak / Quercus pubescens /, Chestnut / Castanea spp./ and others. There are also many endemic species in the interior of the mountain.

There is great diversity in the animal world. There are almost all species of mammals typical of Europe.