Hochwasserschutz Dorf Alpthal - Vormassnahmen 2026 Tender

Bezirk Schwyz - Abteilung Umwelt

About this tender

The Bezirk Schwyz (Abteilung Umwelt) is procuring the preliminary works (Los Vormassnahmen) for the flood protection project for the village of Alpthal, in the municipality of 8849 Schwyz, Switzerland. The overall project is split into two separate lots. This tender covers only the Vormassnahmen lot; the Hauptarbeiten lot (main works) is not part of this invitation. The scope comprises torrent-control works at three watercourses. At the Geissbergbach, a new debris basin (Geschiebesammler) will be built above the Hochweidstrasse, with a concrete block inlet, a concrete outlet wall with steel-beam rake, a new gravel-surfaced maintenance access road, and a block-and-concrete step-pool channel upgrade to the required flood cross-section. A deflection dam will be formed by terrain modification at the upper forest edge. At the Hochweidbach, the channel above the Hochweidstrasse will be enlarged and the steep upper reach stabilised with a step-pool structure. At the Mattlibach, a debris basin with a new outlet structure and rake construction will connect to the existing culvert. At the Karlismattbach, a new debris basin will be built above the settlement edge at Haggeneggweg, requiring prior relocation of utility and spring water pipelines, plus a step-pool channel upgrade below the debris basin. The individual sites are dispersed and not contiguous. Intermediate transport of excavation and topsoil materials crosses sites and requires crossing public roads and third-party land. Detailed measures and boundaries are shown in the project plans, which are available on simap.ch after registration. Contract performance is planned from 31.12.2026 to 30.12.2027, with a possible extension. Variants are permitted, although the contracting authority reserves the right to disregard them without justification. Partial tenders are not permitted.

Bidder eligibility

EK 1 - Own performance: the bidder or joint venture (ARGE) must perform at least 60% of the offer sum in CHF through its own work. Bidders must state which NPK chapters or parts thereof they will perform themselves, using the 'Formular Eigenleistung'. EK 2 - Company references: two references are required, provided on the 'Referenznachweis Unternehmung / ARGE' form. Each reference must show a comparable project completed within the last eight years (completion in 2018 or later), meeting both of these conditions: (1) a water construction project with a construction sum of at least CHF 0.5 million excluding VAT, and (2) construction of a debris basin with barriers/rake and retention volume above 100 m3. References must be provided by the lead bidder or a JV member. Bidding consortia (ARGE) are permitted only under Art. 28 SIA 118. ARGE partners may participate in only one bidding consortium. Subcontractors may bid with multiple consortia. Subcontractors not part of the ARGE must be definitively named before work begins.

How bids are scored

Award is based on three criteria: ZK 1 - Price (weighting 50%, max 50 points): the lowest adjusted offer sum receives 50 points. Offers that deviate by 50% or more from the lowest offer receive 0 points. Points between these are allocated linearly. ZK 2 - Quality / references (weighting 30%, max 30 points): based solely on the completed 'Referenznachweis' forms. Additional points are awarded for the size of the referenced sites (construction sum, debris basin volume), evidence of extensive block-stone and earthworks / dam fill in water-construction projects, and technical demands of the referenced sites (e.g., difficulties in building barriers/rakes, dewatering requirements). Incomplete forms will be disregarded or penalised. ZK 3 - Technical report (weighting 20%, max 20 points): assessed on the additional technical report documents required under chapter 2.9 (Besondere Bestimmungen) and all other bidder information relating to the offer.

Lots

• Lot Vormassnahmen: Los Vormassnahmen (in scope of this tender)

  Preliminary flood-protection works: new debris basins with block-concrete inlets and steel-beam rake outlets at Geissbergbach and Karlismattbach, new debris basin with rake outlet at Mattlibach (connecting to existing culvert), channel upgrades with step-pool structures at Geissbergbach, Hochweidbach and Karlismattbach, deflection dam at Geissbergbach, new gravel-surfaced access roads, and relocation of utility and spring water pipelines at Karlismattbach.

• Lot Hauptarbeiten: Los Hauptarbeiten (not part of this tender)

  Main flood-protection works. Explicitly excluded from this invitation to tender.

Key requirements

• Design and construction of sediment collectors (Geschiebesammler) with concrete intake and steel-reinforced outlet structures on four streams
• Channel widening and bed reinforcement using concrete-embedded blocks and threshold structures to increase flood-discharge capacity
• Terrain modification and deflection dam construction in upper forest reaches
• Utility relocation (water and spring-water pipelines) prior to main works
• Access road construction with gravel-grass surface for maintenance

Procurement contact

The notice names a procurement contact for clarification questions.

Relevant sectors