DEVELOPMENT AND DYNAMICS OF THE SUNGACHA RIVERBED

Abstract

The Sungacha river valley was laid in clay-loamy sediments of the Lake Khanka. Its meanders are dominantly steep with a complex configuration. The development of the Sungacha riverbed (activation or deceleration of the riverbed deformations) in the recent past was affected by fluctuations in the water level of the Lake Khanka. The Sungacha channel runoff, rate of bank erosion and riverbank deformations were rosen with increase of water level in the lake. By reducing of the water level the channel runoff was decreasing and deformations were slowing. Today, however, banks erosion and riverbed deformations ceased almost throughout the river except for the river mouth. Reducing the rate of riverbed deformations had begun in the second half of the XX century as a result of reducing the channel runoff due to increased water intake for agriculture and the growth of the sand bar in the Sungacha river mouth. However the possibility of the channel deformations growth is maintained due to both natural reasons (increase in water content of the rivers on the Khanka plain), and the weakening of anthropogenic impact on the lake and the rivers.