What are Hochwassergefahrenflächen?
Hochwassergefahrenflächen are the flood hazard areas from the hazard and risk maps that German states produce under the EU Floods Directive (2007/60/EC), implemented in §74 WHG. Unlike a legal designation, they are scenario-based: for each probability class (frequent, medium, extreme) the maps model how far a flood of that magnitude could reach. That makes them a reference for graded risk assessment rather than a boundary with legal force. This layer unifies the published hazard areas of 13 states.
How legally binding are Hochwassergefahrenflächen?
Legal status
Reference data
An authoritative input for analysis and screening. It carries no legal effect of its own.
Hochwassergefahrenflächen originate from the hazard and risk maps required by the EU Floods Directive (2007/60/EC) and §74 WHG. They document modelled flood scenarios by probability class and are informational: a reference, not a designation.
What this means for you
The areas trigger no direct building bans. Their practical weight lies elsewhere: authorities consult them in planning, insurers and lenders use them to grade exposure, and they routinely surface as findings in due-diligence reports.
What attributes do the Hochwassergefahrenflächen data include?
- Scenario class: The flood probability class of each area, frequent, medium or extreme scenario, as classified by the state.
- Geometry type: Area polygons or boundary lines, depending on how the state publishes its hazard maps; the type is labelled per feature.
- Waterbody context: Where published, the risk area or waterbody the hazard mapping refers to.
- Bundesland: The source state of each area, for provenance and methodological context.
States implement the Floods Directive with their own modelling and cartographic conventions. The level of geometric detail differs between states, and some publish hazard extents as boundary lines rather than full area polygons. We deliver each state's geometry as officially published and label it clearly, so you always know what a feature represents.
What are Hochwassergefahrenflächen data used for?
- Graded portfolio risk: classify assets by scenario class (frequent, medium or extreme) instead of a binary flood flag.
- Due diligence: document which hazard scenario touches a target property, complementing the legally designated Überschwemmungsgebiete.
- Underwriting: differentiate premiums and exposure using official scenario classes from the EU Floods Directive maps.
- Infrastructure planning: stress-test siting decisions against the extreme scenario before committing to a location.
Where do the Hochwassergefahrenflächen data come from?
Sourced from the official flood hazard and risk maps published by the state water authorities and geoportals under the EU Floods Directive.
Which German states do the Hochwassergefahrenflächen cover?
Available for 13 of 16 German states. Bavaria, Saxony-Anhalt and Thuringia do not publish flood hazard areas at source. Where a state publishes them, we carry them, so the coverage reflects the official publication landscape, stated openly.
Coverage by federal state
- BBBrandenburgAvailable
- BEBerlinAvailable
- BWBaden-WürttembergAvailable
- BYBavariaNot published by the state
- HBBremenAvailable
- HEHesseAvailable
- HHHamburgAvailable
- MVMecklenburg-Western PomeraniaAvailable
- NILower SaxonyAvailable
- NWNorth Rhine-WestphaliaAvailable
- RPRhineland-PalatinateAvailable
- SHSchleswig-HolsteinAvailable
- SLSaarlandAvailable
- SNSaxonyAvailable
- STSaxony-AnhaltNot published by the state
- THThuringiaNot published by the state
Where the federal state publishes this layer, we carry it: 13 of 16 federal states today. Where it doesn't, we say so.
Coverage gap
Your region of interest isn't covered?
Coverage follows what each state and municipality has actually digitised, so there are real gaps, and they are not always where you would expect. Tell us the region and the layer you need and we will look into what can be sourced for it, including data we do not list today.
Tell us what you needHow do you get Hochwassergefahrenflächen as GIS data?
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Frequently asked questions about Hochwassergefahrenflächen
What is the difference between Hochwassergefahrenflächen and Überschwemmungsgebiete?
Hochwassergefahrenflächen come from the flood hazard maps required by the EU Floods Directive (2007/60/EC, implemented via §74 WHG): they model how far floods of a given probability could reach and are informational. Überschwemmungsgebiete are legally designated flood plains under §76 WHG with binding building restrictions under §78 WHG. A site can appear in a hazard scenario without lying in a designated area, and vice versa.
What do the flood scenario classes mean?
The hazard maps distinguish floods by probability: a frequent scenario (high probability, often around HQ10–HQ30), a medium scenario (typically the 100-year flood, HQ100), and an extreme scenario with low probability (HQextrem). Each class answers a different question. The frequent scenario flags recurring operational risk, while the extreme scenario shows the plausible worst case for resilience planning.
Are Hochwassergefahrenflächen legally binding?
No. Hochwassergefahrenflächen are scenario-based hazard areas from the maps produced under the EU Floods Directive: a reference value, not a legal designation. They do not themselves trigger building bans. Binding restrictions attach to festgesetzte Überschwemmungsgebiete under §76 and §78 WHG. In practice, hazard areas still matter: authorities, insurers and lenders use them to assess flood exposure.
Why does the dataset cover 13 of 16 German states?
Bavaria, Saxony-Anhalt and Thuringia do not publish their flood hazard areas at source. Where a state publishes them, we carry them, so the layer covers the remaining 13 states. We prefer stating this gap openly to filling it with modelled substitutes that would not match the official hazard maps the authorities themselves work from.
Why do the geometries differ between states?
Each state produces its hazard maps with its own modelling and cartographic conventions under the shared framework of the EU Floods Directive. The level of geometric detail therefore varies, and some states publish hazard extents as boundary lines rather than full area polygons. The layer delivers each state's geometry as officially published and labels its type, so analyses stay transparent.
How are flood hazard data used in due diligence and underwriting?
Hazard scenarios turn 'is there flood risk?' into a graded answer: a site touched only by the extreme scenario is a different finding from one inside the frequent scenario. Due-diligence teams document which scenario class affects each asset, insurers use the classes to differentiate exposure, and planners use the extreme scenario to stress-test infrastructure siting decisions.