In the end of the 1990ies the model MONERIS was developed by the IGB under leadership of Dr. Horst Behrendt. He had been working in the field of eutrophication and nutrients for a long time. Basing on the development of phytoplankton in surface waters due to eutrophication (Kozerski et al., 1984), he wanted to understand the origin of phosphorus as a major driver. This was why he studied processes of phosphorus accumulation in the soils as well as the eluviations of phosphorus from the soils (Behrendt & Boekholt, 1992). The development and calibration of the modelling approaches based on the analysis of monitoring and statistical data (Behrendt, 1994). He then recognized the tremendous influence of the catchment and its characteristics on nutrient concentrations and loads in rivers. Only when processes in the catchment are understood, processes in the rivers can be modelled.

Funded by regional authorities from Mecklenburg-West Pomerania, Dr. Behrendt created large databases and a set of approaches to quantify nutrient emissions from river catchments from 1994 to 1996. In this course he implemented the pathway concept distinguishing diffuse and point sources emisisons (Behrendt, 1993) following the modelling approaches of Werner et al. (1991). When he analysed emissions and loads in several German catchments, especially in the Elbe and Rhine catchments, discrepancies between the inventories of emissions and the measured nutrient loads became visible (Behrendt, 1996 and 1999). This led to the development of approaches to describe riverine nutrient losses and retention, considering the hydraulic load as the major driver.

During this time, the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (UBA) granted the project to calculate nutrient balances for all German catchments (Behrendt et al., 1999). Within this project the before developed approaches were completed and linked to an improved database. Nutrient emissions and loads were calculated for 300 catchments within 5-year-periods-MONERIS was born, still programmed in a Lotus environment and as a collection of single files without any documentation, but it was working.

The feedback was great and inquiries from several Federal States followed as well as many scientific projects, which allowed further understanding of processes and developments of the model. Consequently the temporal resolution could be improved to yearly calculations. As a very important mile stone, the project „Danubes" (Schreiber et al., 2003; Zessner & van Gils, 2002) was carried out, putting together information from 19 countries within the Danube catchment to calculate nutrient emissions and loads. This project also led to the introduction of the scenario manager. Calculations with the model MONERIS are still carried out and improved on a regular base, since MONERIS is used by the ICPDR.

Modelling of nutrient and heavy metal emissions for German river catchments were carried out i in various projects and the latest version was published in 2010 showing results from 1983 to 2005.

The calculation of nitrogen retention was improved by Venohr (2006), which was done by introducing the temperature as crucial parameter to consider changes in biological activity. Several projects with specific research background were carried out considering input data with higher spatial and temporal resolution. Key aspects were tile drainages (Project Agrum Weser), climate change, mining, coupling with hydrologic and climate models, cost-efficiency analysis of measures (Project GLOWA Elbe), waste water treatment plants and decentralized waste water treatment plants (Project Danube) as well as monthly disaggregation of monthly results (Project IKZM-Oder).

Because of the increased resolution of the input data the complexity and calculation time of MONERIS within the MS Excel environment lacked performance and stability. By introducing an access database and a VBA based calculation code the handling could be improved. After the death of the originator Dr. Behrendt (26.12.2008) a new MONERIS version was published, which was updated and revised under the leadership of Dr. Markus Venohr (MONERIS 2.14.1vba). Approaches to calculate the water surfaces, inputs via erosion, tile drainages, groundwater and urban systems as well as retention in wetlands and surface waters and the monthly disaggregation and the cost efficiency of measures were introduced respectively enhanced.

This new version, also having a new user-interface, was introduced to MONERIS users at the first MONERIS-User-Workshop 2010 when also a new MONERIS manual was presented. The user-interface of the new version contained measures to reduce emissions from the sources agriculture, urban systems and atmospheric deposition. The Presto-Catch Viewer is another tool which directly visualizes MONERIS results according to administration or catchments. In 2011 a Behrendt-memorandun was published with the new MONERIS methodology (Venohr et al., 2011). Further publications, conducted by Dr. Behrendt's earlier companions, can be found dealing with nutrient fluxes and their impact on water quality

In 2012 the final programming was carried out professionally, leading to a new MONERIS version in a C# environment (LINK zu MONERIS 3.0), granting a stable working environment even when when working with larger amounts of input data. Hence there is now a well functioning, stable and well documented MONERIS version. This new version runs under the suffix 3.0 and can be downloaded here. It can be coupled with the Elbe-Expert-Toolbox, which allows the connection to a set of other models and the visualization of the results in this context.

Latest developments MONERIS 3.0

MONERIS 3.0 bases on an object oriented programming, which is more stable and faster than the previous VBA version. There is a new model structure which bases on modules and sub-models representing modelling approaches for inhabitants, areas, water balances, nitrogen, phosphorus, silicium, retention, measures, cost-efficiency and monthly disaggregation. The emission pathways are calculated within these modules, which is different to the Excel and VBA-version, where the emission pathways formed the modules. The user does not necessarily have to deal with this fundamental change, since there is a user interface, which is similar to the old one. Consequently the user may combine measures and introduce the own data as usual. There is a new additional feature, which allows to adapt, enhance, program and introduce modules via a plug-in directory into MONERIS calculations. Modules are available on request. Results are stored in a MONERIS database by default, but they can also be exported as txt files.

On the base of this new structure a monthly calculation is possible which feeds back on a yearly calculation. Hence the hydrologic module could be enhanced considering negative groundwater balances. Land use specific emissions can be also calculated.


Behrendt, H. & Boekholt, A 1992. Phosphorus saturation of soils and groundwater; Joint Meeting of SETAC-Europe, Potsdam; 21-24.06.1992

Behrendt, H. 1994. Point and diffuse load of pollutants in the Rhine River Basin; Verh. Internat. Verein. Limnol. 25; pages 1922-1925.

Behrendt, H. & Opitz, D. 2000: Retention of nutrients in river systems: dependence on specific runoff and hydraulic load, Hydrobiologia, 410, pages 111–122.

Behrendt, H. 1993. Separation of point and diffuse loads of pollutants using monitoring data of rivers. Water Science and Technology Vol 28 (3-5); pages165-175.

Behrendt, H. 1999a. A comparison of different methods of source apportionment of nutrients to river basins. Water Science and Technology. 39(12): 179-187.

Behrendt H; Huber P; Kornmilch M; Opitz D; Schmoll O; Scholz G; Uebe R; (1999) Nährstoffbilanzierung der Flussgebiete Deutschlands. In: UBA-Texte 75/99.

Kozerski, H.-P., Schellenbegrer, G, Behrendt, H. & V. Mohaupt 1984. testing of a complex ecological model for shallow water bodies. Ecological Modelling; Vol. 26, pages 103-113.

Water Science & Technology; 46(8), pages 9-17.

Zessner, M. & van Gils, J. 2002. Nutrient fluxes from the Danube basin to the Black Sea

Link to publications