Stage I - Crossing an old canal of Varna Lake. Two parallel onshore water mains were built and two water lines were installed at the bottom of the canal. The two water mains are made of PE Ø630 Рn 10 pipes. Each water pipe is dimensioned for 270 l / sec. with a length of 290 m.
Stage II - Passing through a new canal of Varna Lake. The existing pipes are used as a pipe case for laying the new water pipes Ø630 PE. The existing inlet and outlet shafts and part of the fittings in them have been preserved. Each of the new water mains has a length of L = 290 m and conducts water at 270 l / sec.
Strengthening of the dam wall between the First and Second Berms, ie. between elevation 1914m and elevation 1900m, with laying of 21000 pcs. tetrapods and gabions. The filling of the collapsed sections for restoration of the batter profile before the installation of the tetrapods is done with gabions type "steel basket" filled with stone. The laying is carried out after a precise geodetic survey of the dimensions of the collapsed sections. The laying of tetrapods is done under water in two layers. The arrangement of the tetrapods is performed by divers according to a scheme approved by the contracting authority, which guarantees the continuity of the first layer and clamping of the tetrapods with the installation of an upper (second) layer. It works simultaneously from both ends of the dam wall.