Switzerland – Construction work – Hochwasserschutz Dorf Alpthal - Vormassnahmen

The implementation of the flood protection project will be carried out in two separate lots. - Lot Preliminary Measures - Lot Main Works The present invitation to tender comprises the works from Lot Preliminary Measures. Lot Main Works is not part of this invitation to tender. The works in Lot Preliminary Measures include the following measures:

Geissbergbach Above the Hochweidstrasse, a new debris collector will be created. The inlet area will be made of concrete blocks. A concrete wall with inserted steel beams (racks) will be created as the outlet structure. Access for maintenance to the debris collector will be from the Hochweidstrasse via a new access road with gravel lawn. The existing culvert Hochweidstrasse remains unchanged. Above the gravel collector, the channel will be expanded to the necessary flood cross-section by means of a newly created pool structure with thresholds, consisting of 1.5 to 2.5 tonne heavy concrete blocks. The blocks in the slopes will not be concreted. Further up, at the exit of the forest, a diversion dam will be created by means of terrain adaptation. Hochweidbach Above the Hochweidstrasse, the channel will be expanded and the discharge cross-section increased to be able to contain the water. In the steep upper area, the brook will be designed as a pool structure by blocks and thresholds. Mattlibach In the upper course of the Mattlibach, a debris collector with a new outlet structure will be created. The inlet area will be made of concrete blocks. The outlet structure will be designed by means of a rack construction and adjoins the existing culvert. Karlismattbach Above the settlement boundary on the Haggeneggweg, a new debris collector will be created. The inlet area will be made of concrete blocks. A concrete wall with inserted steel beams (racks) will be created as the outlet structure. For the construction, prior relocations of industrial and spring water pipelines are necessary. Access for maintenance to the debris collector will be via a new access road with gravel lawn. Below the gravel collector, the channel will be expanded to the necessary flood cross-section by means of a newly created pool structure with thresholds, consisting of 1.5 to 2.5 tonne heavy concrete blocks. The blocks in the slopes will not be concreted. The small, already existing gravel collector will remain unchanged. The detailed measures and exact delimitations can be seen in the project plans. The individual construction sites are distributed over various sub-perimeters and are not contiguous. The intermediate transports of excavated material and humus are partially construction site-crossing, whereby the public roads and properties/roads of third parties must be crossed.