INVESTIGATING THE TECHNICAL CONDITION OF SMALL DAMS OF THE RIVER HRAZDAN

Abstract

The results of field studies of the cascade dams of the Hrazdan River are introduced. In the early 60s of the last century, 20 low dams were built on the section of the Davitashen Bridge-Children's Railway for recreational purposes and protection of the river bottom. The lack of proper maintenance over the past decade has resulted in the clogging of the upstream of these facilities and the failure of sealing equipment. As a result, almost all dams have failed to serve their purpose. The studies assess the technical condition of the structures, determine the volume of sediments in the upper pools, and indicate measures to restore the river system. Along with this, the studies compare the field data with the results of calculations obtained according to a criterion that describes the process of sediment deposition in the upstream of the structures. In some cases, a good correspondence is obtained, in others - significant discrepancy, which is explained by the local applicability of the formulas used in the derivation of the criterion for calculating the minimum particle velocity.

Studies show that when the dam height is low, the slope of the sediment deposit surface in the upstream (transformed, new river bottom) is mainly negative. This is explained by the fact that in the initial part of the deposits, under conditions of shallow depth and high speed, flood flows eroded the accumulated soil. The studies assessed the particle size distribution of sediment deposits. The technical condition and operating conditions of the dams were studied. Research indicates that the strength and stability of dams are provided with the necessary reserves.