The Zalomka River basin constitutes just one part of the wider karst area of Herzegovina. Topographic maps and extensive geological and hydro-geological researches and studies have helped determine the boundaries of the Zalomak river basin of 512 km2 up to Pošćenje, i.e. 544 km2 up to Biograd. These basin boundaries should be regarded as conditional, for this basin is neither topographic nor hydrogeological, for there are two runoff systems, the surface and the underground one that are mainly independent.
The Dabar HPP belongs to the projected hydro power system of hydro power plants on Trebinšnjica and represents the most important hydro power plant in the Gornji horizonti system.
Basic technical data for the Dabar HPP
The Dabar Hydro power plant is a diversion plant consisting of:
Diversion tunnel with the intake house
Channel through the Dabarsko polje
Grebak and Vranjača embankments
Power N = 159.15 МW,
Production E = 251.80 GWh,
Installed flow Qi = 55 m3/s.
Normal water surface of the reservoir NWS = 836 m above sea level. Total reservoir volume (for the NWS) V= 61.80 mil. m3. Crown of the dam level 842 m above sea level. Construction height of the dam 41 m, width at the crown 5 m.
Length of the diversion tunnel L = 12 140 m, tunnel diameter 4.6 m, (part of the route in open excavation is of the length of 1 141 m).
Penstock is of the length of 900 m, and of 3.7 m in diameter.
The machine house is located on the North-Eastern circumference of the Dabarsko polje. The machine house has an underground part (under the level of 490 m below sea level) and an overground part. Three turbines of Francis type with vertical shaft are located in it.
The channel through the Dabarsko polje is of the length of 6360 m. Its cross-section is of trapezoidal shape.
The Grebak and Varnjača embankments have the function of reservoir water tightness.