Public-private partnership for a new flood proof district in Bilbao, Spain

Zorrotzaurre is a formerly derelict industrial peninsula in the Nerbioi-Ibaizabal estuary in Bilbao, Spain, being redeveloped into a mixed-use residential and cultural district. The area sits in a valley exposed to river flooding, sea-level rise and increasingly intense rainfall linked to climate change, with metropolitan Bilbao flood damage estimated at EUR 5.5 million for a 1-in-10-year event and EUR 444 million for a 1-in-500-year event. A public-private partnership, the Comisión Gestora de Zorrotzaurre, was set up between the municipality, the port and provincial authorities and private landowners to finance and manage the redevelopment.

The redevelopment aims to turn the site into a flood-resilient neighbourhood of 5,473 dwellings and about 202,000 m² of economic floorspace, with existing buildings protected against 1-in-100-year rainfall events and new buildings against 1-in-500-year events, in line with Bilbao's Adaptation Plan and the Master Plan for Zorrotzaurre.

Flood protection combines five measures: opening the Deusto canal in October 2018 to turn the peninsula into an island and increase river conveyance; construction of a flood protection wall (started August 2023) to shield the 47 existing buildings on the peninsula; raising the ground level by 1.5 metres for new construction; installing three storm-water storage tanks; and creating extensive green public space along the riverbanks. Costs are shared among the public-private partnership members in proportion to their land ownership (51% public, 49% private).

Opening the Deusto canal cost about EUR 21 million, nearly double the initial EUR 12.1 million estimate; the flood protection wall is budgeted at EUR 1.68 million and the storm-water tanks at EUR 5.7 million. A study by the Basque Centre for Climate Change (BC3) estimated that the combined flood-protection works eliminate damage costs for a 1-in-10-year event and cut damage costs by around 67% for a 1-in-100-year event and around 30% for a 1-in-500-year event.

The project has been slowed by soil contamination requiring decontamination, the relocation of 30 companies, and the 2007-2008 economic crisis, leading to a phased, multi-decade implementation. The public-private governance structure, with costs shared proportionally to land ownership and coordinated through a Management and Coordination Board, is identified as a key enabling factor.