Long-term mean groundwater level dataset for nine German federal states.

Long-term mean groundwater level dataset for nine German federal states Overview This repository contains a raster dataset of long-term mean groundwater level elevation for nine German federal states: North Rhine-Westphalia Bavaria Brandenburg Mecklenburg-Western Pomerania Lower Saxony Saarland Saxony Saxony-Anhalt Thuringia The variable represents groundwater level elevation above sea level. Values are given in meters. Positive values indicate elevations above sea level; negative values indicate elevations below sea level. Negative values occur in some mining areas where topography and groundwater levels have been anthropogenically altered. Repository contents File Description Ground_water_level/GWL_L.tif Main GeoTIFF raster Ground_water_level/GWL_L.tfw World file with georeferencing parameters Ground_water_level/GWL_L.tif.ovr Overview file for faster display Ground_water_level/GWL_L.tif.aux.xml Auxiliary raster metadata and statistics Ground_water_level/GWL_L.tif.xml Additional XML metadata Raster characteristics Item Value Variable Groundwater level elevation Physical meaning Long-term mean groundwater level elevation above sea level Units Meters Sign convention Positive above sea level, negative below sea level CRS WGS84 (EPSG:4326) Grid dimensions 8192 columns x 5376 rows Pixel size in file 0.001953125° Approximate spatial resolution about 200 m; meter equivalent varies with latitude NoData value null; no explicit NoData value declared in the TIFF metadata Value range in file about -210 m to 850 m Data source and processing The raw input data were provided as isolines in shapefile format. Processing workflow: 1. Isolines were cleaned, merged, and harmonized into a common format.2. Isoline topology was validated in ArcGIS.3. A TIN interpolation surface was generated.4. The TIN was converted to raster in ArcGIS.5. For isoline-based input data, the linear method in ArcGIS was chosen over nearest neighbour.6. The raster resolution was selected based on an internal assessment that it was optimal for the source-data accuracy. Known limitations Negative groundwater level elevations in the raster are expected in some mining areas with anthropogenically altered topography and groundwater conditions. Citation Anpilova, Y., Siebert, C., Attinger, S., and Samaniego Eguiguren, L. E. (2026): *Long-term mean groundwater level dataset for nine German federal states*. Zenodo. <https://doi.org/10.5281/zenodo.19132448>