Hydrologic conditions of the Khantaika river closure

Abstract

1. The closure of the Khaitanka River was made under exceptionally difficult conditions, never observed before at other hydrostations. The maximum flow during to closure, at the time of passing the second flood peak, reached 1390 m3/sec. During the third peak, it was 1130 m3/sec. The maximum drop the third peak was 5.29 meters at the upstream cofferdam and 1.46 m at the middle cofferdam. The surface flow velocity was 9.2 m/sec in the gap of the upstream cofferdam and 11 m/sec in the gap of the downstream cofferdam. 2. In spite of the adverse hydraulic conditions, the closure was successful. The contraction of the river channel by the upstream cofferdam created a backwater. This helped freezing and in three days, after the appearance of frazil ice, the river froze over and the inflow of the frazil ice in the intake and in the reach of the river below the cofferdams ceased.