National nitrogen retention maps for Denmark

This repository contains three national nitrogen retention maps for Denmark and associated uncertainties. “TotalRetention_regioner.tif” is the total retention (nitrogen removal) from the source location to the coast, “Grundvandsretention_regioner.tif” is the retention during transport in the groundwater and “Overfladevandsretention.tif” is the retention in the surface water system, i.e. streams, lakes, wetlands and inundated areas. The maps for the total and groundwater retention are aggregated from a 100 m grid into regions with a minimum size of 50 ha based on similarity between neighbouring grids. For surface water, the spatial resolution is defined as the contribution catchment discharging to the individual retention environments, e.g. a lake catchment. The total retention is supplemented by two maps “TotalRetention_usikkerhed_regioner.tif” showing the uncertainty in the total retention estimated for each region and “TotalRetention_standardafvigelse_regioner.tif” displaying the standard deviation between the individual grids within each region. All maps are calculated using data for the period 2000 – 2021. The nitrogen retention maps have been developed in a collaboration between GEUS and Aarhus University. (2025-08-29).

Date ( Publication ): 2025-08-29

Edition: dk.geus:hydro:retention

Purpose: The purpose of these maps is to provide a comprehensive and detailed overview of nitrogen retention in Denmark, including where and how nitrogen is removed in both groundwater and surface water. The maps can be used as a tool to assess variations, uncertainties, and regional differences in nitrogen removal, thereby supporting research, management, and planning of environmental and water management initiatives.

Status: Completed

Point of contact

The Geological Survey of Denmark and Greenland (GEUS) - Anker Lajer Højberg ( )

Author

Aarhus University - Hans Thodsen

Author

Aarhus University - Christen Duus Børgesen

Maintenance and update frequency: As needed

Point of contact

The Geological Survey of Denmark and Greenland (GEUS) - GIS-support

Keywords ( Theme )

Dataset
Geology
Nitrogen
Retention
Nitrogen retention

Forskningsemner Forskningsemner ( Theme )

Geoscience and history policy

Geografisk Geografisk ( Place )

Denmark

Access constraints: Other restrictions

Use constraints: Other restrictions

Other constraints: CC BY 4.0

Spatial representation type: Grid

Denominator: 100000

Metadata language: Da

Character set: UTF8

Topic category

Geoscientific information
Environment

Supplemental Information: Documentation includes appendicies: National kvælstofmodel - version 2025. Udvikling af nye kvælstofretentionskort. Bilagsrapport. De Nationale Geologiske Undersøgelser for Danmark og Grønland. GEUS særudgivelse. ISBN 978-87-7871-620-0, https://doi.org/10.22008/gpub/38955.

Højberg, A.L., Thodsen, H., Børgesen, C.D. (red.) Andersen, A.H., Andersen, L.T., Audet, J., Bach, E.O., Christiansen, D.T., Christiansen, D.A., Conde, J.T., Falk, F.A., Frederiksen, R.R., Giannini-Kurina, F., Gudbjerg, J., Han sen, B., Henri, C.V., Henriksen, E.S., Hermansen, N., Hoffmann, C.C., Høyer, A., Iver sen, B.V., Jakobsen, R., Jørgensen, M.S., Kim, H., Kjeldgaard, A., Koch, J., Kronvang, B., , Liu, J., Madsen, R.B., Martin, N.L., Molis, M., Mortensen, M.H., Motevalli, A., Muff, E., Møller, I., Ondracek, M., Petersen, R.J., Pugliese, L., Rosenkrantz, A., Sandersen, P., Schneider, R.J.M., Sonnenborg, T.O., Stisen, S., Sørensen, P.B., Thorling, L., Tornbjerg, H., Troldborg, L., Uldall-Jessen, L., Voutchkova, D., Aamand, J.. 2025. National kvæl stofmodel - version 2025. Udvikling af nye kvælstofretentionskort. Metoderapport. De Na tionale Geologiske Undersøgelser for Danmark og Grønland. GEUS særudgivelse, ISBN 978-87-7871-619-4, https://doi.org/10.22008/gpub/38954 doi: 10.22008/gpub/38954.

Reference system identifier: ETRS 89 / UTM 32N (EPSG:25832)

Distribution format

WMS ( )

Distributor

The Geological Survey of Denmark and Greenland (GEUS) - Anker Lajer Højberg

OnLine resource: Download ( WWW:DOWNLOAD-1.0-http--download )
Download datasets from GEUS Dataverse

OnLine resource: Interactive webmap ( WWW:LINK-1.0-http--link )
Viewing the dataset on the web portal

OnLine resource: Report ( DOI )
National nitrogen model - version 2025. Development of new nitrogen retention maps.

OnLine resource: 1 ( OGC:WMS-1.3.0-http-get-capabilities )
WMS for Grundwater

Hierarchy level: Dataset

Statement: Lineage for the dataset "National Nitrogen Model – version 2020": The data originates from the development of the Danish National Nitrogen Model (NKM), designed to quantify nitrogen leaching and retention in Danish aquatic environments to support environmental assessments and decision-making. The model was developed by the Geological Survey of Denmark and Greenland (GEUS) in collaboration with Aarhus University and the Danish Ministry of Climate, Energy and Utilities, and was published in May 2021. The development included the collection of extensive data on soil conditions, precipitation, agricultural practices and hydrology, the construction of a numerical model to simulate nitrogen transport and transformation, validation against observed data, and implementation in a decision support tool. The model combines process-based and statistical methods, including the NLES model for nitrogen leaching, hydrological models for groundwater and surface water, and GIS-based spatial analysis and visualization.