FEATURES OF THE CONSTRUCTION AND THE OPERATION OF WATER BASINS LOCATED ON LOESS TERRITORIES

At the droughty territories of Uzbekistan agricultural production is possible only if reservoirs have been created. So far as precipitations falls on the territory of the Republic of Uzbekistan during a year is very uneven, the creation of conditions for uniform irrigation may be achieved by he accumulation of winter-spring high-flood waters in reservoirs. He researches, conducted at big reservoirs (Charvak, Andijan, Tupalang, Gissarak and others), which are located in rivers Sirdarya and Amudarya, showed, that the construction and the operation of such hydro-technical objects is the reason of the rise of many unfavorable processes and phenomena.

Loess deposits of various geneses, in accordance with their nature, have weak water-stability. During the first years of operation of reservoirs, which were built on loess territories, the intensive remaking of the shores of these artificial reservoirs is observed.

In the first turn that is observed as the formation of a big number of landslides, which lead to the diminishing of reservoir's useful volume. Besides that, the change of hydro-geological conditions on all adjoining territory as a result of high filtration properties on loess rocks is marked. In particular, the steady raising of ground waters level is marked.

As a result, subsidence phenomena, flora's impoverishment on significant territories are observed, the engineering-geological conditions of the construction of ground objects get worse. One of important moments is the change of the seismic regime of reservoir and nearby territories.

According to instrumental observations the increase on order of origin intensity near the reservoir is established. That has led to the rise of additional residual deformations on significant territories near reservoir.