Advising political decision-makers at the Federal state level:

e.g. cooperation project GROWA+ NRW 2027 for implementing EC Water Framework Directive

The Institute Agrosphere (IBG-3) has been supporting several federal German states for more than 15 years in the development of nutrient management concepts for the management planning of their water resources. For this purpose, the models mGROWA (water balance, discharge pathways), DENU-WEKU (nitrogen) and MEPhos (phosphorus) developed at IBG-3 are used to represent the following diffuse and point nutrient inputs to groundwater and surface waters in high spatial resolution: drainage, groundwater runoff, wash-off, water erosion, interflow, and atmospheric deposition on water surfaces, as well as municipal wastewater treatment plants, industrial direct dischargers, small wastewater treatment plants, storm sewers in separate systems, and combined sewer overflows. In North Rhine-Westphalia, the models have been in use since 2009.

To further develop the models for the site conditions prevailing in NRW and to update and consolidate the data basis and to incorporate the relevant state-wide and regional expertise, the GROWA+ NRW 2027 cooperation project was launched at the end of 2022. In addition to the NRW State Office for Nature, Environment and Consumer Protection (LANUV) and the NRW Geological Survey, the NRW Chamber of Agriculture, which calculates regional agricultural nitrogen balances for NRW, is also involved in the project.

The mGROWA-DENUZ-WEKU-MEPhos models are used to determine the amount of nitrogen and phosphorus currently entering groundwater and surface waters in a defined area. Based on this status quo analysis, it is estimated how high the reduction requirement of the agricultural N balance surpluses is in order to achieve the environmental protection goals. The results of the phosphorus modeling are also used to update the "eutrophic areas" (§13a DüV). Through the modeling, the Federal State of NRW is supported in the management planning for the North Rhine-Westphalian parts of the river basins of the Rhine, Weser, Ems and Meuse, e.g. with regard to providing forecasts for achieving the good surface water and groundwater status by 2027.

Key points:

  • Funding Institution: MKULNV (Ministry for Climate Protection, Environment, Agriculture, Nature Conservation and
  • Consumer Protection of the State of North Rhine-Westphalia)
  • Duration of the project: 01.09.2022 -31.08.2025
  • Project partners: Geological Service (NRW) and Chamber of Agriculture NRW (LWK)
  • Target groups:
    • Agricultural and water management authorities of the state of NRW
    • Stakeholders (water boards, water protection advisers, etc.)

Comparable advisory projects are currently also being carried out for the German states of Schleswig-Holstein, Mecklenburg-Western Pomerania, Hamburg, Hesse, Saxony-Anhalt and Rhineland-Palatinate.

Contact persons:

Prof. Dr. Frank Wendland and Dr. Björn Tetzlaff

Institut für Bio- und Geowissenschaften, IBG-3

Tel.: 0049 171 3003 594


Last Modified: 03.07.2024