1.2.02 Examining the Rhine and Ems – management systems for water quality in river basins

Rivers form a crucial part of the water cycle. Among other things, they need to be protected from nutrient loading to guarantee their function in the long term. The European Water Framework Directive (WFDWater Framework Directive of the European Community; See: EU Water Framework Directive.) calls for this safeguarding measure with the demand for corresponding environmental development. The REGFLUD project saw an interdisciplinary team tackle these requirements and adopt a scientific approach to studying the systematic management of regional river basins. Using the examples of the Rhine and Ems rivers, the experts investigated agricultural measures to improve the quality of the water.

German waters are not as heavily loaded with nutrients as they were in the past; they have undergone a substantial clean-up over the last few decades. The biggest contributions to this positive development are an improved procedure for cleaning up wastewater and a reduction in the amount of phosphates used in detergents. Despite this success in water protection, there are still equally large sections of water suffering to a greater or lesser extent from nutrient loading. The majority of nutrients in rivers originate from diffuse sources – i.e. they are impossible to pinpoint precisely – predominantly as a result of farming. Agricultural production introduces nitrogen and phosphorus, which have an impact on the ecological balance and the usability of water and seas. As a further step towards improving the water balance, the 2000 EU Water Framework Directive calls for management systems to be established for all river basins.

New requirements

Many public bodies in charge of water usage and protection are entering new territory when it comes to diffuse nutrient loading. Unlike isolated loading, neither the cause nor the effect can be clearly identified. This is primarily due to the diverse natural conditions such as water balance and soil properties that affect the transportation, bonding and degradation of the nutrients underground and in the groundwater. In many cases, the authorities lack the tools and methods necessary to decide on efficient strategies or measures to reduce diffuse water loading through agriculture.

Different regions undergoing investigation

This is where the BMBF-funded REGFLUD research project stepped in to assist (full name: “Management regionaler Flusseinzugsgebiete in Deutschland (REGFLUD) – Rahmenbedingungen und Politikoptionen bei diffusen Nährstoffeinträgen (Stickstoff und Phosphor) der Landwirtschaft” – management of regional river basins in Germany – framework conditions and policy options for diffuse nutrient loading (nitrogen and phosphorus) in agriculture). The aim of the project was to devise scientific methods that could be used to help determine efficient measures for reducing the diffuse nutrient loading of river basins as a result of agriculture. The investigations took place between July 2001 and October 2005 and focused on two river basins: a section of the Rhine basinPart of the earth’s surface that is drained by a river and its tributaries. We distinguish between above-ground and underground basins. The drainage divide marks the boundaries of the basin. between the Sieg, Erft, Wupper and Ruhr tributaries, and the entire basin of the River Ems. The regions investigated differed in terms of both agricultural usage and local conditions.

Interlinking systems and models

The focus of the REGFLUD project was on interlinking the Regional Agricultural and Environmental Information System (RAUMIS) for Germany with the hydrological GROWA98 and WEKU models. RAUMIS enables the analysis of the regional effects of various agricultural and agrienvironmental policy measures on agricultural land usage, production and income and on diverse agri-environmental relationships, e.g. excess agricultural nutrients. The GROWA and WEKU models use this as a basis – while factoring in a whole host of local conditions such as soil, climate and topographyScientific discipline involving the surveying, portrayal and description of terrain, locations and landscapes. – in order to map nutrient loading of water by area. The deriving of efficient measures to reduce nitrogen loading from agriculture using the combined model was tested with a nitrogen tax and a restriction on livestock density.

Tailored measures required

The model results show that the different regional conditions lead to very different proportions of excess nitrogen from agriculture being found in the groundwater and surface water. The proven effects of a nitrogen tax and a restriction on livestock density, strongly deviating from each other within areas, document that only tailored measures to provide a sustainable solution to the nitrate problem will help in a given area. The integrated consideration of local conditions and the complex interaction through the combined model makes it possible to develop more efficient water protection measures.

Putting into practice

The AGRUM-Weser pilot project run by Germany and neighbouring countries is developing other regional solutions using the REGFLUD approach. The combined model has been expanded to include the MONERIS model, which factors in all relevant loading paths. The work is being conducted in collaboration with those responsible for executing the requirements of the WFD in the Weser river basin and also takes country-specific procedures into account. The aim is to analyse and evaluate operational measures for reducing the effects of diffuse nutrient loading from agriculture. As such, the decisive step has been taken to put the REGFLUD research project into practice.

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1.2.03 SEDYMO research project

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1.2.01 River management in the Elbe basin