Session K.pdf - Clarkson University

snow cover thickness, potential movements and deformation of the Fusegates. Duringthe ice melting period, the overspilling head over the fixed labyrinth and over the Fusegateswas also reported.In the winter of 2001/2002, the period of negative temperatures began in mid-November. In the second week of December, the temperature fell down to -20 o C. Thenbetween mid-December and the beginning of January, it fluctuated between -10 o C to-12 o C (Figure 3). During this period, ice thickness reached 50 cm at the surface of thereservoir and 60 cm upstream of the Fusegates (Figures 4 and 5). The Fusegate buckets,wells and drainage holes were frozen through. The downstream side of the spillway wascovered with solid ice up to 10 cm thick. Ice was formed on the vertical faces of theFusegates on the downstream side and on the walls of the concrete labyrinth. At the endof the first week and throughout the second week of January, there were temperatureswings from -21 o C to -2 o C during three days, followed by a sharp drop of temperatureto -23 o C and a rise to +2 o C. Up to mid-February, the temperature fluctuated around 0 o Cwith an amplitude of -4 o C to +4 o C (Figure 3, curve 1).Fig. 3. Plot of daily average temperature at Khorobrovskaya hydrounitfor winter period of 2001/2002 and 2002/2003Fig. 4. Ice Thickness Variation beside Fusegate No. 3Despite these severe conditions, no displacements or noticeable deformations of theFusegate elements were observed, nor disturbances in the operation of the concretelabyrinth.It should be noted that there was no Hydroplus Fusegate crest overflow during the wintermonths, as its edge level is 10 cm higher than the labyrinth spillway crest level. The354