HYDROELECTRIC POWER PLANT VISEGRAD
Usage of hydro potential in the lower part of the upper course, i.e. on the line Goražde-Višegrad, was observed in many variants.
In the efforts to preserve existing infrastructure, that is the road and narrow gauge railroad along the Drina valley, the two-steps variant has been considered: HPP Višegrad lower and HPP Ustiprača. After the narrow gauge railroad Ustiprača-Višegrad, Rudo had been closed, it was decided to use complete head on this part of the river course on one step, i.e. HPP Višegrad higher.
Through design documentation and voluminous economic analyses with optimal respect to infrastructure, geological and topographic preconditions, comparing more variants, a micro location 2,7 km upstream from the historical bridge in Višegrad was chosen for dam profile, with maximum water level of 336,00 m asl.
Terrain research for designing of this profile started in 1976. Paralelly with drawing up plans on different levels of processing, investigation works were carried out in the period between 1976 and 1982.
The data for these bases were collected in the long period (from 1926) from a large number of hydro and meteorology stations in the basin and on the watercourse. By processing these data authorative parameters for design documentation were adopted. They are given in the table below.
|Mean perennial discharge||342 m3/s|
|Maximum two year discharge||2.084 m3/s|
|Maximum five year discharge||2.886 m3/s|
|Maximum ten year discharge||3.400 m3/s|
|Maximum fifty year discharge||4.700 m3/s|
|Maximum hundred year discharge||5.350 m3/s|
|Maximum thousand year discharge||7.455 m3/s|
|Maximum ten thousand year discharge||9.785 m3/s|
|Minimum discharge||26 m3/s|
|Average annual rainfall||1.230 m3/s|
|Number of days with rainfalls in a year||124 m3/s|
|Average annual temperature||10 oC|
|Maximum temperature||39 oC|
|Minimum temperature||-24 oC|
On the bases of detailed engineering-geology mapping, it is established that the future reservoir area has a complex geology-tectonic construction basically consisted of paleozoic and down triasic shale and sandstone, middle and upper-triasic limestone and dolomites, hornstones, tuffs and eruptives, often covered with terraced sediments and recent alluviums.
It is estimated that these rocks will protect reservoir from water leaking. It is also proved that on several locations in the reservoir there are conditionally stable slopes and old, inactive slippery spots, which were additionally examined and their stability was estimated in conditions of planned reservoir oscilations. For some locations rebuilding measures were suggested and carried out.
Just on the damming place and its immediate surroundings terrain is made of clastic sediments, down-trias, middle-trias limestones and dolomites, products of volcano-sediment complex and eruptions with noticable tectonics.
For all this and because of detailed definition of stone mass in geological, geotechnical and hydro geological sense, voluminous examinations with examining drill were undertaken, as well as examination of waterproofness, making probation grouting fields, geotechnical tests (examination of deformity with pressing pillow, examination of removing and slippery resistance) and by application of many well-known geophysics methods.
|Module of elasticity||3.000 - 17.000 MPa|
|Module of deformation||2.500 - 14.500 MPa|
|Resistance on removing||j = 48oC - 52oC C= 2,5 - 3,5kPA|
|Seizmic zone of the area||VIIo MCS scale|
|Designing seizmicity||IXo MCS scale|
Parameters from table above are taken for design.Hydropower plant with parametres from the table below was designed on the chosen damming profile with mean perennial discharge og 342 m3/s with maximum respect to topographic, geological, geotechnical, hydrogeological preconditions as well as consumptions demands and influence on environment.
|Maximum water level||336,00 mnm/m asl|
|Minimum water operating level||331,50 mnm/m asl|
|Tail water level for Q600||291,60 mnm/m asl|
|Maximum gross head||48,20 m|
|Maximum net head||48,16 m|
|Constructive head||43,00 m|
|Total cubic capacity of the reservoir||161 hm3|
|Flooded area||850 ha|
|Type of the plant||Adjacent to the dam|
|Type,number and power of the turbine||Kaplan, 3x105MW, 315MW|
|Number and power of the generator||3x115MW, 345MW|
|Voltage of the grid connection||400 kV|
|Average annual production||1.010 GWh|