Bagaevsky Hydroelectric Complex Dewatering

Dewatering of water bodies formed by damming the right bank of the Don River

Stroytransgaz Group runs the largest infrastructure project not only in the Southern District, but also nationwide — Bagaevsky Hydroelectric Complex (BSH) — in Rostov Region near Arpachin village. The project addresses a number of challenges that affect regional quality of life: insufficient water supply for drinking, domestic, industrial, agricultural, fishing and navigational purposes.

At the moment, construction of the Bagaevsky Hydroelectric Complex requires dewatering of spillway dam pit. Reduction of groundwater level for construction of hydraulic structures is one of the primary tasks in excavation works.

Dewatering of water bodies formed by damming the right bank of the Don River

Dewatering, i. e. artificial lowering of the groundwater level, is closely related to pit excavation and includes several phases. At first, the water is pumped from the surface of the reservoirs that were formed after damming the right branch of the Don River by cofferdam structures. The works are performed using motor pumps installed on intermediate berms (horizontal platform along the top edge of the pit to protect it against collapse). Once the pit is drained, the excavation starts and is protected by relief wells located inside the pit. When the water level drops to minus five metres, the needle filter units will come in. The design provides for 7 sets of LIU-6BM needle filter units. Needle filters are 4 to 7 metres long. As the depth of the pit increases, the needle filters will be re-installed in tiers. In short, once the water level drops by 3 to 4 metres, the system moves to the next depth. Protected by needle filters, the pit will be excavated down to design elevation of minus 9.3 m.

Project background:
The hydroelectric complex under construction will be composed of a shipping lock with upper and lower approach channels, a spillway and earth fill dam, a meandering fish bypass and spawning channel and a fish passage lock, industrial and technical facilities, and a camp for operating personnel.  To ensure navigation safety, channel-regulating dams will be constructed, as well as shore protection dams that will prevent the development of bank erosion processes (washout and collapse), protect from the impact of ship waves and reduce the negative impact of waters. In order to ensure guaranteed waterway dimensions (depth – 4 m, width – 80 m, bending radius – 500 m) in the section from the Kochetovsky Hydroelectric Complex site at km 3004.5 of the waterway of the Integrated Deep Water System (IDWS) to the Bagaevsky Hydroelectric Complex site at km 3089 of the IDWS waterway, dredging and river cut-off are envisaged.