The powerplant of Zarnowiec is the largest pump storage scheme in Poland and is responsible for ensuring the electric supply in peak times and the stabilisation of the voltage in the polish electrical power system.
The permanent load changes during operation and the extreme differences in temperature have imposed a severe stress to the reservoir lining.

WALO was commissioned to completely rehabilitate the surface of the lining on the steep sided slopes which have an inclination ranging from 1:2.75 up to 1:2.
After removing the surface of the upper sealing layer and refitting the damaged zones, WALO fitted a new Dense Asphaltic Layer (DAC) followed with an application of new mastic coating.
A mixing plant was installed close to the site for the production of the bituminous mixes.
WALO managed all the logistics associated with the mixing plant.

WALO constructed the cells as part of a composite lining system of some 17,800m² using DAC formulated in the company’s Zurich laboratory to a design mix unique to the project. The lining system comprised a 300mm mineral attenuation layer; 200 mm sub-base material layer; 60mm asphaltic binder layer, 80mm dense asphaltic concrete layer and a mastic seal coat to the base, side slopes and bund areas. The works involved the placing of asphalt by paver and winch on a 40m slope. Once the lining was completed, a 300mm thick layer of leachate drainage stone was applied to the whole area.