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TRANSBOUNDARY WATER MANAGEMENTMankind on the shores of the Baikal:the transboundary ecosystem ofRussia and MongoliaE. I. Lishtovannii and A. N. Matveev, Irkutsk State University, Russia; B. Bayartogtokh,Mongolian State University; and T. Villemin, University of Savoie, FranceLake Baikal, located in South-Eastern Siberia, is one ofthe most unique lakes in the world. It was formed 25-30million years ago and corresponds to a rift valley that isalmost subsiding today. The lake contains about 20 per cent ofthe world’s surface freshwater supply and its transparency isstriking up to 40 metres deep. It is a place of biological waterflora and fauna diversity on a global scale. At present, more than2,630 species and varieties of plants and animals are knownto science, two thirds of which are endemic. 1 The number ofknown Baikal organisms is continuously growing, as revealedby research done by Russian and other scientists.Lake Baikal was inscribed on the United Nations Educational,Scientific and Cultural Organization’s (UNESCO) World HeritageList in 1996. In 2008, the Russian Government announced that thelake is one of the seven wonders of Russia.Lake Baikal contains about 20 per cent of the world’s surface freshwater supply and2,630 plant and animal varietiesImage: Evgeni KozyrevThe largest tributary of Lake Baikal is the Selengariver, which springs in Mongolia and brings morethan 60 per cent of the water influx to the lake. TheSelenga river basin is a transnational mega-ecosystem,the largest water basin of Mongolia and the Republic ofBuryatia region of the Russian Federation. The Selengabasin comprises more than 80 per cent of the Baikalbasin, indicating the significant role of Mongolia in thelong-term ecological health of the lake.The Selenga, flowing into Lake Baikal, forms theworld’s largest freshwater delta occupying an area of 680km². This delta was included in the Ramsar Conventionlist of Wetlands of International Importance in 1996 –a decision explained by the river’s abundance of floraand fauna, as well as its considerable role in the purificationof polluted Selenga waters coming into the lake.The drainage basin of the Selenga river is 447,060 km 2 ,with a length of 1,024 km (including the headwaters ofthe Ider River which are 1,476 km long). The length ofthe river in Russia is 409 km. The river basin is directlyaffected by industrial and agricultural sites located inMongolia and in the Republic of Buryatia, and indirectlyaffected through the air by industrial sites of the Irkutskregion. Surface pollution, caused by precipitation andanthropogenic sources, directly influences all elements ofthe Selenga ecosystem and gradually percolates throughunderground layers. There is a more intense migrationof toxic components through these structures. Linearlyelongated centres of underground toxic water pollutionare formed in the area and might enter the Selenga as wellas the Baikal water system. In such a situation, the deltaplays a significant role in Selenga river self-purificationprocesses. The delta is a massive wetland area, whichundergoes intensive processes of binding and sedimentationof river-driven organic matter and pollutants.In the Selenga delta area, the most apparent changesin the lake water level result from the natural andanthropogenic processes connected with the IrkutskHydroelectric Power Station. The dam was constructedin the late 1950s on the Baikal’s outlet, the AngaraRiver, 60 km from the place where the Angara flowsout of the lake. Seismic, tectonic and other endogenous[ 81 ]