Main Results of Complex Researches of Water Regime, River Bed Evolutions and Ecological Condition of the Argun River

The article presents the results of a comprehensive study of the water regime, channel processes and the ecological state of the Argun River. Poor water quality of the Argun river is determined by high concentrations of COD, phenols, zinc, manganese, copper, and iron; the water quality of the tributaries is higher than that of the main river. The content of most metals in the Argun River water quality according to the zooplankton saprobity index is estimated as class II (slightly polluted), and according to the indicator organisms of zoobenthos - from class II to class V. The worst quality parameters in terms of chemical and biological indicators are characteristic of the upper part of the river. As a result of the channel deformations the Argun river is highly likely to change the state border line in the direction of Russian territory, which is caused by the massive construction of bank protection facilities on the Chinese coast. We have found 80 reaches with dangerous development of channel processes, urgent measures are required for 14 of them. Mathematical modeling shows that as a result of water management measures in the territory of the PRC, the Argun River runoff decreased by an average of 1.8 km3 per year compared with the background period (1959-1971), which is more than half of the Argun River average annual runoff in the border cross section. The processing of Earth remote sensing data showed a reduction in the area and duration of flooding of the floodplain Argun and the oppression of floodplain vegetation below the channel of flow transfer. The flow transfer led to a general decrease in runoff, but did not affect the passage of catastrophic floods. To solve the problem of floods, it was proposed to repair existing and build new protective structures.