Ice-thermal reservoir regimen during first years of operation of the krasnoyarsk hydroelectric plant

Conclusions

Experience with the filling of the reservoir at the Krasnoyarsk hydroelectric plant explained certain characteristics of the ice-thermal analyses for the first year of operation of the reservoir, namely:

• 1. The water temperature in the deep low-flow reservoir during its summer filling in the first years was higher than that obtained for the operating reservoir.

• 2. Freezing of the reservoir, after filling, took place at a later time because of the increased heat reserves stored during the summer when the reservoir was filling with flood flows. As a result of the increased heat inflow from the bottom, the temperature of the bottom water layers was higher during the winter than the temperature established after prolonged operation of the reservoir.

• 3. At the downstream side, the water temperature depends upon the depth at which the intake structures are located.

  During the initial period of reservoir operation the deeper the location of the low-level outlets, the higher the temperature of the releases. The temperature difference decreases as the releases increase.

• 4. During the first winter after filling the reservoir and reduced releases at the Krasnoyarsk hydroelectric plant, a large unfrozen area persisted downstream. Its large size resulted from the warm water releases from the reservoir.

The absence of a downstream ice cover during the winter period leads to a drop in the water level. This should be taken into account in the design of intake structures within the limits of unfrozen areas.