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Article InfoThe paper deals with of the relations between the forest ecosystem, calcareous rocks and content and composition of soil organic matter in the Golo Bardo area in West Bulgaria. In that area Rendzinas are used mainly for forestry, viticulture and pastures. A specific study based on the accumulation of soil organic matter according to the data on the composition of the soil organic acids. The research on the soil organic matter composition provided information on the course of the humification processes in studied soils. Soil organic matter accumulation in Rendzinas depends on different factors, such as land use and climatic conditions. Soil has rapid transformations of organic residues and strongly decomposed plant tissue predominates. There are often signs of active work of the soil mesofauna. Studied soils have good reserves of organic carbon high degree of humification. The organic carbon content varies in a wide range from 0.8 to 7.2 %. The humic acids prevail over fulvic acids, and the degree of humification is higher in deeper horizons. According to the C/N ratio the humus type is Mull in almost all horizons. Studied soils are biologically active that have favorable impact over the soil structure and vegetation. Rendzinas have high potential of organic carbon sequestration.

The Dospat-Tesbel complex of hydraulic structures is the first stage of the Vycha sequence, which in the future will consist of six hydroelectric schemes: Teshel, Devin, Tsankov Kamyk, Mikhalkovo, Antonivaanovtsy, and Y4ichim (Fig. 2). The composition of the structures of the Dospatteshel complex, a rockflll dam with a clay core (Fig. 1), forms an alpine reservoir with volume of 445 million ms. The topographic conditions of the dam site and the reservoir basin are favorable. In addition to the flow of the Dospat River, the reservoir collects, by means of a special diversion system, a part of the flow of the rivers Vyshcheritsa, Kanina, Bistritsa, etc. The upstream diversion with a diameter of 3.1 m has a total length of 16,220 m (tunnel 15,060 m and open channel, aqueduct, and siphon 1160 m). A large part of the tunnel runs through granite with a coefficient of elastic resistance of 300-1000 kg/cm s, and the last section is in limestones with evident manifestations of a karsL The head in the diversion increases from 6 atm at the inlet to 11 atrn at the surge shaft; the power-plant complex consists of a twochamber surge shaft with a diameter of four and height of 107 m, an underground chamber for two free-discharge butterfly valves, penstock with a diameter of 2. 6 and length of 560 m with a metal lining, a machine hall for two 30 MW units, and other auxiliary ~tructures.The collection system for diverting the flow of other rivers includes the Vyshcheritsa-Kanina diversion which collects the stream flow of the. Vyshcheritsa and Kanina rivers, tributaries of the Mesta River, in a volume of 74 million m3/year and directed to the Dospat River; the. Zmeitsa diversion which collects the flow of the Karadzha, Selimkhodzhovo, and Beldonovo rivers and delivers it to the main diversion; the Bistritsa diversion which diverts the flow of the Bistritsa River, a tributary of the Mesta River, into the Dospat reservoir in a volume of 21 million mS/year.After completing the Barutin, Lyava, and Dyasna diversions it will be possible to direct into the Dospat reservoir about 160 million m3/year through the main diversion of the Teshel hydroelectric power station which will operate here at a high head. For economic considerations the installed power at the Teshel hydroelectric power station is comparatively small; the generation of electric power is also small: 180 (first line) and 274 million kWh/year after completing the entire complex.The particular value of the complex of hydraulic structures is that the diversion of the flow of the Mesta river basin into the basin of the Vycha River will permit irrigating large areas of heretofore unutilized lands and at the same time will make it possible to create on the Dospat-Vycha sequence economicaily effective hydrnelectric 305 6 Fig. 1. Dosp.atDam. 1) Upstream cofferdam; 2) surcharge; 3) slope stabilization by large stone; 4)rockfill (angle of internal friction q = 35", unit weight ~ = 1.65 t/mS); 5) three-layer fiker; 6) clay core (a= 23 ~ ], = 2.0 t/mS); 7) grouting gallery; 8) surchar...

Проведены исследования почвенного покрова в зоне воздействия полигона захоронения твердых бытовых отходов. Исследованы гранулометрический состав, магнитная восприимчивость, кислотно-щелочной показатель, редокс-потенциал, содержание гумуса в почвах. На основании полученных данных сделаны предварительные выводы о геоэкологическом состоянии почвенного покрова. Ключевые слова: почва, магнитная восприимчивость, гранулометрический состав, полигон захоронения твердых бытовых отходов.