Flood risk management at municipality level in Navarra, northern Spain.

In Navarra - a 10,000 km² region in northern Spain with 700,000 inhabitants - 50 municipalities are required to implement a local plan for flood risk management.The Regional Flood Risk Management Plan of Navarra identifies these 50 municipalities based on their level of risk. It also establishes the structure of each local plan, which must follow four standardized documents.Municipal plans include one pre-emergency level and four emergency levels: 0, 1, 2, and 3. The pre-emergency level does not necessarily need to be communicated to the public. The emergency levels are defined as follows:Level 0: Flooding has not yet begun, but streamflow has significantly increased.Level 1: Expected flooding will affect low-lying areas near riverbanks.Level 2: Severe damage is expected in urban areas.Level 3: The regional government assumes control of the local plan because the situation exceeds local capacity.The activation of each emergency level of the plan has to be communicated to the population.To prepare a plan, we visit each municipality and hold technical meetings with local authorities and staff, including the local police. We inspect strategic locations where local resources have historically acted to minimize flood damage. Typical actions include door-to-door warnings, street closures, and on-site alerts in public buildings such as schools or nursing homes.The most critical task in drafting the plan is defining the thresholds that trigger each emergency level. These thresholds are based on historical rainfall and streamflow data within the river catchment. Usually, streamflow data from upstream measuring stations is used, while in small catchments, accumulated rainfall over a specific time period is also considered.Once the paper version of the plan is complete, it is transferred to a digital platform that enables coordinated operations by local authorities (mayors and other officials) and staff. This platform includes both a mobile app and a web-based interface, offering:Real-time data updates every 10–15 minutes (from different observing networks: regional government, Spanish Meteorological Agency, Water Agencies, etc.).Easy activation of emergency levels.GIS maps showing the location of all planned actions.A mass SMS alert system for rapid communication with the population using predefined messages.Since 2018, technicians from the Government of Navarra and Orekan have worked to implement these operational and consistent structures. They are based on local knowledge gathered from municipal staff, site visits, and collaborative planning. Information about the plans is shared with residents through detailed leaflets and public information sessions in each municipality.