First researches of the underwater ecosystem communities of an underground channel built in 1950s (Balaklava bay, Sevastopol)

The results of the first studies of the ecosystem state of the underwater part of the channel, artificially created in the middle of the 20th century on the western shore of the Balaklava Bay (Sevastopol) as a naval base of the Black Sea Fleet for the submarines repair, are presented. Channel's ecosystem is determined by uniqueness of anthropogenic formation and considered as analogue of natural Black Sea cave. Hydrospelological survey of the channel and biological studies allowed assessing its current state, the nature of biofouling of its walls and anthropogenic and technical pollution of the bottom. Macrofauna of the channel wall biofouling is represented by the Mytilaster lineatus community, which has a high level of species abundance (about 80 species have been registered) and quantitative development. Both in taxonomic diversity and in quantitative terms, this community is comparable to the rocky substrate community near open Crimean coasts, but with a smaller share of crustacean group development. Due to weakened hydrodynamics, well developed fauna of bryozoans forming plurannual crusty structures and single sponges is observed on the channel's walls. In contrast to the channel walls biofouling, its bottom macrofauna has relatively lower quantitative and qualitative composition. Meiobenthos in the channel’s wall biofouling is represented by 18 higher taxa (type, class, order) of Protozoa and Metazoa with predominance of harpacticoids by abundance. Meiobenthos of the soft bottom of underground channel is represented by 15 higher taxa with predominance of free-living nematodes and harpacticoids by abundance. Average density of meiobenthos in the channel’s bottom sediments is comparable with similar parameters of its development in open water areas and Sevastopol bays.

Development of the underground erosion of the soils adjoining the concrete constructions (on the example of Zagorsk pumped storage power plant, ZPSPP-2)

The matter of such a dangerous geological process as suffosion is briefly considered in the article. Some examples of destruction and removal of the suffusion unstable breeds on the contact with the concrete structure are given. Sone cases of vertical (downward and upward) and sloping streams in relation to a concrete construction are considered. It is proved that after the formation of the primary underground channel the suffosion process passes into the erosive one. This transition is smoothly and gradual, hidden from the immediate observation. However, the erosive process development leads to the repeated increase in the intensity of the incoherent soil destruction. In case of existence of soil removal zone, not only the large underground channel is formed, but also large cavities in the zone of contact of the concrete structure and the soil massif are formed. It quite often leads to the emergency situations. Studied the example of the Zagorsk PSPP-2 (ZPSPP-2). The development of the erosive process under the ZPSPP-2 building led to the formation of large cavities (up to 10 m) and to the general subsidence of the building of the plant and of the retaining wall 3 (RW3) on 1.17 m down.