Rehabilitation of Urft Dam - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 792

Figure 24.25 Equipotentials in the middle of the valley, monitoring and analysis (Wittke et al. 2012)
Figure 24.26 Quantities of seepage water, monitoring and analysis (Wittke et al. 2012)
The measured quantities of water seeping into the drainage system and the inspection
galleries show considerable differences between the left abutment and the remaining
areas (Fig. 24.26). This is probably caused by the higher permeability of the sandstone
layer in comparison with the silt- and claystones.
Figure 24.27 shows the measured quantity of seepage water in the middle of the valley
and at the left abutment as a function of storage level. Up to a level of 315 m a.s.l., the
quantity of seepage water increases linearly with increasing storage level. Above this
level, a higher increase in seepage water quantity is observed. This result indicates that
probably due to the large temperature changes (Figs. 24.23 and 24.24) and the corre-
sponding strains, the permeability of the masonry in the upper part of the dam is higher
than in the lower part of the dam.