Third Rhône Correction (R3) — Widening and Restoring Switzerland's Largest River for Flood Safety

The Third Rhône Correction (R3) combines levee reinforcement, riverbed lowering and widening of the Rhône from Gletsch to Lake Geneva (about 162-170 km, Valais and Vaud). Widening is roughly 50% of current width on average, with local sections doubled or tripled for sediment management. The goal is to protect over 100,000 people and prevent potential damage of up to CHF 10 billion; revitalisation aims to improve aquatic and terrestrial habitats and create recreation space.
Governance: the Valais Grand Council approved the plan in 2000 and a June 2015 referendum backed financing with 57%; federal approval followed in 2016. Early estimates were CHF 2.3 billion; the Swiss Federal Audit Office now cites CHF 3.6 billion, of which CHF 2.1 billion is federal, and about 870 ha of land involved. Agricultural opponents proposed deepening instead, but independent experts judged it neither sustainably safe nor legally compliant.
Honest caveats: an audit dated August 2026 found FOEN must steer canton revisions more firmly, only partly recovered excess subsidies (CHF 0.5-1.0 million) from Valais, lacked a risk-based monitoring framework, and warned that major modifications may need new parliamentary approval. Flood-protection performance is design-based rather than yet evaluated against major floods, and carbon, fire and soil outcomes are not reported.

Read the full analysis: https://www.efk.admin.ch/en/audit/implementation-of-the-third-rhone-correction/