General The data source shallowgroundwater is a geospatial dataset of multipolygons that represent the estimated areas, in the Flemish region of Belgium, where the mean lowest groundwater level (MLW; Knotters & Van Walsum, 1997; Van Heesen, 1970) is less than approximately 2 m below soil surface (hence, “shallow” groundwater). We expect groundwater dependent species and communities to be present within these areas. Outside these areas we assume they are groundwater independent. We combined several data sources in order to estimate these areas. Compilation of the data source We compiled the dataset through an iterative process of adding specific data sources (referred in the description of attributes below), followed by validation steps based on both the actual presence of groundwater dependent habitat types or regionally important biotopes (Natura 2000 habitat map) and in situ measurements of groundwater levels (Watina+ database). The coverage of these validation data by shallowgroundwater was 96.9% and 98.6% respectively. Most steps to compile the data source were done manually using QGIS. Final steps were done in R; see R-code in the GitHub repository 'n2khab-preprocessing' at commit 1b004e1. Detailed properties The data source is a GeoPackage with a single spatial multipolygon layer shallowgroundwater in the ‘Belge 1972 / Belgian Lambert 72’ coordinate reference system (EPSG-code 31370). All attributes are boolean (true/false), each indicating if a polygon was selected from the corresponding data source by applying a set of criteria. Multiple attributes can be true for a given polygon. In order to reduce file size, polygons were dissolved by each unique combination of the values of all attributes. Hence the dataset consists of multipolygons (also multipart polygons) rather than single (part) polygons. The different attributes of this dataset reveal for each polygon (1) the data source(s) we relied on and (2) the selection criteria we applied to judge if the mean lowest groundwater level is less than ...