Annex 4 analytical methods

model description

general description

acronym: GREEN

name: Geospatial Regression Equation for European Nutrient losses

main purpose: A statistical model used to assess the impact of different nutrient sources, i.e. agriculture, wastewater and industrial discharges, atmospheric deposition, on freshwater and coastal waters.

homepage: https://cran.r-project.org/web/packages/GREENeR/

Developer and its nature

ownership: EU ownership (European Commission)

ownership additional info: —

is the model code open-source?: YES - An R implementation of the code (GREENeR) is publicly available.

Model structure and approach with any key assumptions, limitations and simplifications

details on model structure and approach: —

model inputs

Model inputs are:

Annual climate data (precipitation)
Annual input of fertilizer application (manure, mineral fertilizers), atmospheric nitrogen deposition and biological fixation, extent of agricultural and non-agricultural area.
Discharges of N and P from industrial installations, untreated and treated wastewater. The latter are usually estimated from population density and connectivity to waste water collecting and treating systems, or available datasets of wastewater discharge points (Vigiak et al. 2018; 2020; 2023). Geomorphological information is needed in order to build the hydrographic model used in the calculation. The model consists of a set of interconnected sub-basins each containing a segment of the stream network.

model outputs

Model outputs are:

Nitrogen and phosphorus source apportionment
Annual discharge of nitrogen and phosphorus loads, and concentration in stream water.

Intended field of application

policy role

Appraisal of policy scenarios in terms of mass discharges and concentrations of N and P, by identifying areas that might be affected by nutrient pollution , evaluating the effectiveness of the legislation and policy options in reducing nutrient loads entering freshwaters.

policy areas

Agriculture and rural development
Environment

Model transparency and quality assurance

Are uncertainties accounted for in your simulations?: NO - The model is occasionally calibrated depending on the availability of data. Calibration provides an indication of the error associated to the model in predicting loads and concentrations.

Has the model undergone sensitivity analysis?: NO - The model, insofar as spatially distributed, is sensitive to the input emissions. Sensitivity analysis is only carried out for model parameters, and not on data inputs.

Has the model been published in peer review articles?: YES

Has the model formally undergone scientific review by a panel of international experts?: NO - Only in the context of the scientific peer review of journal papers.

Has model validation been done? Have model predictions been confronted with observed data (ex-post)?: YES - The model has been extensively compared with measured N and P concentration data and to other model outputs, as documented in the references provided.

To what extent do input data come from publicly available sources?: Entirely based on publicly available sources

Is the full model database as such available to external users?: NO - (To be made available with the latest release)

Have model results been presented in publicly available reports?: YES

Have output datasets been made publicly available?: YES

Is there any user friendly interface presenting model results that is accessible to the public?: YES

Has the model been documented in a publicly available dedicated report or a manual?: YES - The model does not require a user’s manual. A full description of the model can be found in Grizzetti et al. (2021). The R implementation package includes a vignette that can be used for guidance.

Intellectual property rights

Licence type: Free Software licence

application to the impact assessment

Please note that in the annex 4 of the impact assessment report, the general description of the model (available in MIDAS) has to be complemented with the specific information on how the model has been applied in the impact assessment.

See Better Regulation Toolbox, tool #11 Format of the impact assessment report).