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Hydraulic engineering & harbours

Ostravice drainage tunnel and Å ance waterworks

Staré Hamry, Czech Republic / 11.2012 - 10.2013

The construction of the drainage tunnel was one of the primary measures to ensure the operational reliability of the Šance waterworks. Specifically, the project served to divert groundwater that ran down a neighbouring mountain slope and into the raised dam of the waterworks. This process had the potential to damage the reservoir’s sealed core.

When it was first established in 1968, the Šance waterworks facility was the tallest raised dam structure in the country with a height of around 65m. Today, it is the main source of drinking and utility water for the industrial areas of the cities of Ostrava and Karviná. It serves to prevent flooding and also regulates the water level of the Ostravice River below the reservoir.

Photo: tunnel section coated with jetcrete and netting; a metal grating running lengthwise down the middle of the floor; fluorescent lighting tubes on the ceiling

Facts & Figures


Company

PORR a.s.

Type

Hydraulic engineering & harbours

Runtime

11.2012 - 10.2013

Principal
Povodí Odry, státní podnik

Most modern construction materials ensure stability.

The excavation of the tunnel, which was nominated Construction of the Year 2014 by the Czech Chamber of Chartered Engineers and Technicians, was executed under very difficult hydro-geological conditions below the groundwater level. A 50m-long section of the drainage tunnel was excavated through unstable hillside scree, while blasting was required to bore the rest of the length through rock areas.

Modern construction materials, such as significant quantities of fibreglass reinforcement and anchor elements, were used to replace classic steel grating and bolts. Access structures and elevated constructions were also made from composite materials. These long-lasting materials will ensure the sustained stability of the tunnel, which is constantly exposed to the effects of groundwater.

What ultimately counts in the construction business is successfully completed projects. PORR has many of these.