Characteristic parameters of the hydroelectric power plants on the cascade. (see table)

The system of water projects - Vah Cascade 2 was built between 1943 and 1955.

The Trencianske Bohuslavice water project consists of a dam, reservoir, dykes around the reservoir and a feeding canal for the Kostolna hydro electric power plant.

The dam is underlain by impermeable Neogene shales above which is a surface layer of sand and gravel sediments.

The area of the river basin above the dam is 9,267 km2 and the average annual precipitation is 960 mm.

Characteristic flows through the dam:
Q364 – 25.6 m3.s-1
Q355 – 34.1 m3.s-1
Qa – 142.0 m3.s-1
Q100 – 2000.0 m3.s-1
Q100 – reflects the effects of the Orava and Liptovska Mara reservoirs

Dam design
The dam has nine flowthrough fields. Four of them have an inner diameter of 25 m, are closed by steel slab sluice gates 3.5 m high, with a flap 1.4 m high located on the upper edge of the gates. They are used for discharging waters to the old riverbed of the Vah. The other four fields each have an inner diameter of 12 m, are closed by slab gates with a damming height of 5 m (control waterflow to the canal). The last, nineth field with an inner diameter of 12 m is dammed by a gate with a 5.6-m-high flap. This field should be used as a lock in the future.

On the right bank, near the dam, between a riverbank pillar and the left inundation dyke there is a 150-m-wide free water bypass. The maximum capacity of the dam with all outlets open is 3,000 m3.s-1. The free bypass serves as a reserve to be used when the dam ceases to be functional at disasterous floodwaters.

The dam holds back a water reservoir with a total volume of 3.25 million m3 and a maximum water level of 208.2 m above sea level. The reserve volume of the reservoir including part of the volume of the Skalka waste water canal is 1.75 m3. The water level near the dam is 4.9 above the riverbed and on average about 1.5 m above the surrounding country.

The reservoir's dykes rise 1 m above the calculated 100-year water level and their crest is 3-m wide. The dykes are built of sand and gravel and reinforced with and 15-cm-thick pavement set in concrete. The waterside slope's inclination is 1 : 1.75 and that of the outer slope is 1 : 2.

The feeding canal is 4.8 km long and the longitudinal inclination of its bottom is 0.08 %. It has a trapezoidal cross-section with a bottom width of 19.0 m and slope inclination of 1 : 1.75. The canal's flowthrough capacity is 180 m3.s-1 and the maximum depth of water reaches 7.56 m. The slopes and bottom of the canal are sealed by a 15-cm-thick concrete layer. The outer slopes of the dykes have a top layer of humus with grass.

The hydroelectric power plant is situated on a derivation canal km 4.8 from the Trencianske Biskupice dam.

Information & Contact:

Research Institute of Water Management,
Nabr. arm. gen. L. Svobodu 5,
811 02 Bratislava,
tel.: 00421 (2) 59343111,
fax: 00421 (2) 54415743