Damming of the Irtysh River at the construction site of the Shul'binsk hydroelectric station

Conclusions

• 1. The final stage of damming the Irtysh River was carried out without complications, which was promoted by the favorable regime provided by streamflow regulation by the Bukhtarma and Ust'-Kamenogorsk reservoirs.

• 2. The upstream and downstream cofferdams of the pit of the first phase after their opening were subjected to intense self-erosion for several hours, and then they were dismantled by excavators and a dredge.

  The width of the gap on September 29, 1987 at 0800 h was respectively 107 and 125 m. The maximum depth at the site of the downstream cofferdam was 6.5–7.8 m.

• 3. Good dismantling of the cofferdams provided their high discharge capacity, as a consequence of which the differences of water levels and current velocities in the gap of the embankment began to decrease. In the final stage of damming the maximum velocities did not exceed 3.5 m/sec with a discharge of 73.8 m³/sec. The inflow discharge was 665 m³/sec and the final drop on the embankment was 0.67 m.