Systematic observations of seepage during construction and putting the structures into operation have been being carried out since 1979. The seepage regime is monitored in the following structures:dam of the upper reservoir, including stretches where it adjoins the water intake and territory beyond the dam, including stretches of the abutments; water intake with upstream and d~. ~nstream retaining walls; natural slope serving as the base of the penstocks with territory adjoining on both sides; powerhouse with the territory of the slope adjoining it on the upstream side; downstream dam of the lower reservoir. The extent of equipping the structures with monitoring and measuring instruments (MMIs) as well as the program and composition of on-site observations of seepage were elucidated rather thoroughly earlier in [1, 2]. In connection with this, in the present article these features are presented schematically in a minimum amount; emphasis is placed on elucidating the formation of the characteristic features as well as anomalies of the seepage regime. At the same time, since the state of the slope of the penstocks, including its ancient movements, is presented in detail in a number of works [3][4][5], only a brief characterization of its seepage regime is given here.Observations of seepage are essentially combined and include measurements of the hydrostatic levels and pressures, seepage and drainage discharges, and temperature of the filtrate. They are carried out by means of free-flow drop piezometers (DPs), free-flow embedded piezometers (EPs), pressure embedded piezometers (PEPs), pressure side embedded piezometers (PSEPs), string pressure transducers with a porous nozzle (SPTPs), string temperature transducers (STrs), and means of measuring flow rates (water meters, measuring weirs).General information on the number of units of MMIs installed and operating in the structures is given in Table 1. They are installed in the design amount on the majority of structures (dam of the upper reservoir with the adjacent territory, intake, powerhouse, downstream dam). At the same time, according to the results of observations and actual state, certain structures (upstream retaining walls of the intake, slope of the penstocks) required substantially more MMIs. For it, stance, due to activation of the "Southern" landslide 130 drop piezometers instead of the 20 specified by the project were installed to monitor the seepage regime of this stretch. After filling the upper reservoir in 1989, a rise of the hydrostatic levels was noted by two piezometers under the downstream shoulder of the right-bank dam in fluvioglacial gravel--pebble deposits. Ten piezometers were installed to refine the extent of these deposits and evaluate the danger of a rise of levels.For the most part the installed MMIs are maintained in a satisfactory state. At the same time, against the background of the relatively favorable state of the piezometers and remote instruments, observations of the drainage discharges are not being carried out in the full amoun...
