General concepts
colour codes
geo portal
instructional videos

Geo portal


The geo portal lets you consult all waterinfo maps. The map layers are divided into different groups. The layers are ordered alphabetically, but can also be filtered by name or source. You can add a layer to the map by ticking "active" in the left column. The name of that layer will then also appear in the map layers module, where you can tick or untick the layer and adjust the visibility. The collapsible legend in the map contains the symbols used for each layer.
With the webmap service, you can use the maps on your own computer. 

Map query

If you click on the map, a pop up appears with available information for the item you clicked. The selected item will be yellow in the map.   

The map tools module allows you to measure distances on the map, search for addresses and locations, or add an address to your favourites. You can also generate a pdf report for a plot, with information about flooding.



In the map layer query module, you can tick the information that you wish to bring up for a specific location. You can then select this location on the map. You can select a point, a polygon drawn by you or a plot. You can view the results of your query in the map query results module. For each requested layer, a new tab page with a table is displayed here. If you click on a row of the table, the map will zoom to this location.


Description of map layers

A summary of the various map layers with explanation, can be found here:

Maps from the Flemish Hydrographical Atlas (VHA)

Map layer Explanation
Polders and waterboards This map shows the boundaries of the public bodies of water with the responsibility of realizing the objectives of integrated water management within their territory.
River basins The boundaries of the 11 Flemish river basins can be found on this map.
VHA zones A VHA zone is a sub-hydrographical unit that represents the capture zone of a watercourse or a section of a watercourse. The positioning of the boundaries of the VHA ones is based, among other things, on drainage via surface water, relief and comparable surfaces of these zones, and is included in the Flemish Hydrographical Atlas.
Watercourse axes (VHA) This map is an element of the Flemish Hydrographical Atlas and contains the axes of navigable watercourses (waterways), non-navigable classified waterways and a number of non-classified waterways.

Water assessment maps

Map layer Explanation
Run-off areas This map shows to where rainwater will run-off above ground, based on the digital elevation model.
Erosion-sensitive areas This map shows the areas that are sensitive to erosion.
Areas prone to groundwater flow This map provides a first indication of the sensitivity to disruption of shallow groundwater flow.
Slope map This map divides Flanders into four different categories of slopes.
Infiltration-sensitive soils This map shows the soils where infiltration will be relatively easy; this does not mean, however, that infiltration is excluded in soils that are not shown on this map.
Areas prone to flooding Here a distinction is made between areas actually and potentially prone to flooding. Areas actually prone to flooding are areas that were recently flooded or areas where there is a significant probability of flooding based on models. Areas potentially prone to flooding are areas where flooding is possible only under extreme weather conditions or when flood defences fail, e.g. dyke breaches. These are, in principle, historical valleys and marshlands.
Recently flooded areas (RFA) This map includes an inventory of all recorded and documented floods since 1988. The map is based on reports from local authorities, emergency services, helicopter flights, etc.
Flood-risk areas This map was laid down by the Royal Decree of 28 February 2007 and shows the locations where the possibility of damage is greatest. A fire insurance policy, which also covers natural disasters, such as flooding, is based in part on this map, both for calculation of the premium and as grounds for the possible refusal to insure new buildings.
Naturally floodable areas (NFA) This map is based on the soil map and indicates all areas where sedimentation by the water system has occurred. These may relate to sloping areas (colluvia), flooding from the waterway (alluvia) or historical flooding by the sea. In principle, this refers to historical valleys and marshlands.
Winter bed map This map shows the main flooding areas along navigable waterways.

Hazard and risk maps under the Floods Directive (ORL)

Map layer Explanation
Particularly vulnerable facilities This map shows facilities that are either difficult to evacuate (hospitals, healthcare institutions, prisons, schools, etc.) or of importance in crisis situations (police stations, fire stations, etc.) and that are located within the floodable area associated with a low probability of flooding.
Economic risk This map shows the weighted combination of all available damage maps, expressed as "the annual average damages" or €/m²/year.
Economic damages This map shows, for a particular scenario (low, medium, high probability), the economic damages, calculated as a function of water depth, time of occurrence (e.g. for agriculture), flow velocity and rate of rise of the water level, expressed in €/m².
Hydrographic network This map represents the watercourses associated with a significant potential flood risk in accordance with the Floods Directive.
Vulnerable cultural-historical objects This map shows the cultural-historical buildings (castles, mills, churches, monasteries, etc. either listed as historic monuments of not) and landscapes (anchor points, areas containing relics, etc.…) that are located within the floodable area associated with a low probability of flooding.
Line infrastructures This map shows various physical (e.g. roads and railways) and non-physical line infrastructures (e.g. bus routes) that play an important role in the movement of people and goods to, in and through the floodable area. The map shows road sections, bus routes and railway lines running through the floodable area associated with a low probability of flooding.
Flood hazard maps Flood hazard maps show the physical properties of flooding associated with the flooding scenarios (extent of flooding, water depth, flow velocity, etc.).
Floodable area This map shows the areas exposed to the risk of flooding. Such flooding may arise from both waterways and the sea. The map shows the extent of flooding for the three different flooding scenarios (low probability, medium probability, high probability).
Potential damages This map shows the potential (maximum) damages in the event of flooding and is expressed in €/m². This value is obtained by applying the damage calculation to a fictitious water depth map (all of Flanders under 10m of water) and gives an upper limit for the economic damages.
Overall flood risk maps This risk map shows the potential adverse consequences expressed in terms of inhabitants potentially affected, the type of economic activtity, the IPPC installations and the potentially affected protected areas associated with each flood scenario.
Rate of rise in water level This map shows, for a particular flood scenario, the maximum rate of the rise in the water level, as calculated using the hydrodynamic models. This map has only been created for the coast where this parameter is relevant.
Flow velocity This map shows, for a particular flood scenario, the maximum flow velocity in the floodable area, as calculated using the hydrodynamic models. Flow velocities are given only for complete 2-dimensional models that allow for an accurate estimate of the flow velocity (Coast).
Water depth map This map shows, for the floodable area, the maximum water depth associated with each scenario (low probability, medium probability, high probability), expressed in centimetres. The water depth is calculated as the distance between the water surface and the ground level, based on the hydrodynamic models and the digital terrain model (DTM) for Flanders.

Extra Map layers

Map layer Explanation
Municipal districts This map shows the boundaries of the municipal districts in Flanders.
Large-scale reference database (LRD) The large-scale reference database is a database containing large-scale data, such as buildings, plots of land, roads and their layout, waterways, railways and civil engineering structures. These objects are detailed and accurately measured (source: AGIV).
Land registry parcels This map shows the areas of land, their boundaries and the buildings on them.
Medium-scale orthophoto mosaics, winter recordings This map is built up from aerial photographs with a resolution of 25m (source: AGIV).
AGIV orthoimagery Digital photographic aerial views that provide a clear picture of the soil cover.
Integrated Water Policy – Pre-emption Right – perimeter areas The Integrated Water Policy Decree stipulates that the Flemish Region has a right of pre-emption when property or land, located in the riparian zones delineated in the basin management plans and in the flooding areas delineated in the basin management plans or catchment area management plans, is sold. This dataset delineates these areas. The digital database is not a legal document.
Signal areas Signal areas are areas that have not yet been developed but are already firmly designated under the zoning plan (residential area, industrial area, etc.) and which may also be instrumental in the approach to flooding because they are floodable or because they have specific soil properties enabling to them act as a natural sponge.