An interactive flood‑risk map for municipalities has been created
Municipalities located in flood‑risk areas will no longer need to rely on rough estimates or different data sources. By integrating available data, the State Data Agency (Statistics Lithuania) has created a new interactive map that enables accurate assessment of potential flood risks and identification of how many and which residents and buildings fall within flood‑prone areas.
From need to solution
The solution was developed in response to the need of municipalities to provide accurate data for the flood‑risk reduction measure “Increasing resilience to extreme hydrometeorological phenomena” implemented by the Ministry of Environment of the Republic of Lithuania.
Until now, municipalities preparing various risk plans, applications, and certificates had to indicate:
- how many residents live in flood‑risk areas;
- how many buildings fall within flood‑inundation zones;
- what area would be affected under different scenarios.
The requirements set by the Ministry of Environment and its subordinate institutions specify that the data provided must be accurate. The aggregated map created by the State Data Agency makes it possible to monitor and assess current and precise indicators in real time.
Official and up‑to‑date data
This tool was created using the flood hazard and risk maps of the Environmental Protection Agency, combined with georeferenced cadastre data (building geometries), data from the Population Register on the number of declared residents by address, as well as address data and coordinates from the Address Register.
Data in the system are updated automatically, ensuring that municipalities always see current information.
Due to data security requirements, this interactive tool can be used only by authorised users of the analytical environment “Savivaldos DataLab” (Municipal DataLab) – representatives of municipalities, civil protection, and other responsible institutions. For interested parties, the standard flood hazard and risk map is available on the website of the Environmental Protection Agency of the Republic of Lithuania .
How does the map work?
The system operates on a GIS (Geographic Information System) basis: official flood‑area polygons are linked with address points or building geometries. If at least one point of a building’s contour falls within the flood zone, the building is considered to be at risk. The system allows users to select a specific municipality, highlight an area of interest, view the number of addresses and residents, and export the data.
Three different scenarios are applied in the application:
- high‑probability flood,
- medium‑probability flood,
- extreme‑event flood.
The following types of floods are distinguished:
- river floods (spring floods related to snowmelt),
- coastal (sea) floods.
It is worth noting that when converting raster flood data into vector polygons, the boundary error may be up to 3 meters. This is related to technical limitations of data processing and does not have a significant impact on the overall risk assessment.
Added value – a single version of the truth
This interactive map enables municipalities to assess risk under different possible scenarios. The solution ensures a single reliable data source, faster response in emergency situations, and the ability to integrate additional social or infrastructure indicators.
This allows municipalities not only to submit funding applications, but also to realistically model evacuation scenarios and plan social assistance and civil protection actions.
Although the tool is interactive and intuitive, the State Data Agency regularly organizes training sessions for municipal representatives in the “Savivaldos DataLab” analytical environment to ensure its smooth use. A review of the flood‑risk map and training for public‑sector specialists will take place this Friday at 10:00 a.m. More information is available at https://vda.lrv.lt/lt/renginiai/mokymai-savivaldos-datalab-lc4/.
The interactive flood‑risk map is a step toward advanced, data‑driven municipal governance that strengthens resilience to extreme hydrometeorological events.