Germany : River Ruhr

Revised Terms of Reference [28/11/2000] Heavily Modified Waters in Europe Case Study on the River Ruhr Research Project MAKEF Dr. P. Podraza University of Essen Institute of Ecology, Department of Hydrobiology 45117 Essen Phone: 0049-(0)201-183-3868 Fax: 0049-(0)201-183-4583 Email: [email protected] Members of the research project MAKEF (co-authors) • Dr. P. Podraza University of Essen Institute of Ecology, Department of Hydrobiology 45117 Essen • Prof. Dr. Klaus Greve Rheinische Friedrich-Wilhelms-Universität Bonn, Geographic Institute, 53115 Bonn • Martin Halle umweltbüro essen, A. Bolle & Partner GbR Rellinghauser Str. 334 f 45136 Essen • Dr. Thomas Zumbroich, Dr. Andreas Müller Büro für Umweltanalytik Bonn/ Essen Breite Str. 21 53111 Bonn • Dirk Glacer Ingenieurbüro Glacer Horster Str. 25e 45279 Essen 2 Table of Contents page PART I 4 1 Preface [to be drafted by project managers] 5 2 Summary Table 7 3 Introduction 9 3.1 Choice of Case Study 9 3.2 General Remarks 9 4 Description of Case Study Area 11 4.1 Geology, Topography and Hydrology 11 4.2 Socio-Economic, Geography, and Human Activities in the Catchment 13 4.3 Identification of Water Bodies 19 4.4 Discussion and Conclusions 21 PART II 24 5 Physical Alterations 25 5.1 Pressures and Uses 25 5.2 Physical Alterations 26 5.3 Changes in the Hydromorphological Characteristics of the Water Bodies and Assessment of Resulting Impacts 32 5.4 Discussion and Conclusions 32 6 Ecological Status 34 6.1 Biological Quality Elements 34 6.2 Physico-Chemical Elements 35 6.3 Definition of Current Ecological Status 36 6.4 Discussion and Conclusions 43 7 Identification and Designation of Water Bodies as Heavily Modified Fehler! Textmarke nicht definiert 7.1 Provisional identification of HMWB Fehler! Textmarke nicht definiert. 7.2 Necessary hydromorphological changes to achieve Good Ecological Status (GES) Fehler! Textmarke nicht definiert. 7.3 Assessment of Other Environmental Options Fehler! Textmarke nicht definiert. 7.3.1 Identification and definition of the beneficial objectives served by the modified characteristics of the water body Fehler! Textmarke nicht definiert. 7.3.2 Alternatives to the existing ”water use“ Fehler! Textmarke nicht definiert. 7.4 Designation of Heavily Modified Water BodiesFehler! Textmarke nicht definiert. 7.4.1 Identification of human benefit by achieving GESFehler! Textmarke nicht definiert. 7.4.2 Economic analysis of measures to achieve GESFehler! Textmarke nicht definiert. 7.4.3 Comparing the costs to achieve GES with the costs to achieve GEPFehler! Textmarke nicht 7.4.4 Designation of water bodies and objectivesFehler! Textmarke nicht definiert. 8 Definition of Maximum Ecological Potential 45 8.1 Determining Maximum Ecological Potential and Comparison with Comparable Water Body 75 9 Definition of Good Ecological Potential 77 9.1 Determination of Good Ecological Potential 77 PART III 79 10 Conclusions, Options and Recommendations 80 11 Bibliography 81 3 PART I 4 1 Preface [to be drafted by project managers] (1 page) [insert the standard preface - drafted by the project managers - briefly explaining the European project on heavily modified water bodies as the context for the individual case study. This should explain the context to readers of the case study, who may not be familiar with the European project. ] 5 2 Summary Table (2 pages) Annex IV: Information on Case Studies (one Table for each Case Study) Item Unit Information 1. Country text Germany 2. Name of the case study (name of water body) text Ruhr 3. Steering Committee member(s) responsible for the case text Dr. Ulrich Irmer, Dr. Bettina Rechenberg, German Federal study Environmental Agency (UBA) 4. Institution funding the case study text National Ministry for Education and Research (BMBF) 5. Institution carrying out the case study text University of Essen, University of Bonn, umweltbüro essen, Büro für Umweltanalytik, Büro Glacer 6. Start of the work on the case study Date 01.09.2001 7. Description of pressures & impacts expected by Date - 8. Estimated date for final results Date 31.03.2002 9. Type of Water (river, lake, AWB, freshwater) text River 10. Catchment area km2 4488 km² 11. Length/Size km/ km2 219.2 km (Ruhr); 5021 km (running water in the River Ruhr catchment) => Stream density in the catchment: 0.98 km/km² 12. Mean discharge/volume m3/s or m3 Mean discharge near mouth 1991-2000: 75.1 m³/s; mean discharge winter 2000: 132.1 m³/s; mean discharge summer 2000: 32.9 m³/s 13. Population in catchment number 2.2 Mio. 14. Population density Inh./km2 490 Inh. / km² 7 15. Modifications: Physical Pressures / Agricultural influences text Water abstraction for drinking water supply, cooling and industrial use 16. Impacts? text 14 reservoirs (volume: 473,6 Mio m³), 5 impounded lakes (volume: 19,1 Mio m³), 17 hydropower stations (162 Mio kWh/a), 89 wastewater treatment plants, 489 wastewater treatment and discharging units (e.g. CSO), 49 weirs in the middle and lower Ruhr 17. Problems? text Eutrophication (algal blooms) in the lower Ruhr, local oxygen depression in summer, local critical free ammonia concentration (NH3) in spring, local heavy metal pollution of river sediments, disruption of river continuum and sediment transport. smoothing of flow dynamics. 18. Environmental Pressures? text Urbanisation along the middle and lower Ruhr (one of Germany's biggest industrial centre: Ruhrgebiet), agriculture and forestry in the catchment of the upper and middle Ruhr, recreation (e.g. shipping, fishing) 19. What actions/alterations are planned? text - Restoration measures/habitat improvement - Enhanced Wastewater Treatment - Construction of fish pathways - Establishment of buffer strips. 20. Additional Information text 21. What information / data is available? text - land use patterns - data on water chemistry and discharge - survey on treatment and discharge of wastewater (e.g. wastewater treatment plants, combined sewer overflows (CSO)) - German Water Quality Survey, - German River Habitat Survey, - inventories of fish and benthic invertebrate fauna 22. What type of sub-group would you find helpful? text 23. Additional Comments text 8 3 Introduction (2 pages) 3.1 Choice of Case Study The River Ruhr was chosen as a case study object for several reasons: • The River Ruhr is located in Northrhine-Westfalia, a German state with well defined reference water courses (reference conditions on water quality, hydrology, stream morphology, macroinvertebrates, fish, vegetation). So the natural scale for assessing stream quality is available. • The catchment of the River Ruhr represents several different stream types in different landscape areas (= different reference conditions). • The River Ruhr represents rivers in highly industrialised areas. The multiplicity of different pressures and impacts increases the probability of a designation as heavily modified waterbody. • The water management association “Ruhrverband” surveys water quality and manages the discharge of the river Ruhr. Thus, detailed data on these subjects are available over long periods of time and were kindly provided to be used for the case study. • The Department for Hydrobiology at the University of Essen (Dr. Daniel Hering) is coordinating another EU-research project on the implementation of the EU WFD "The Development and Testing of an Integrated Assessment System for the Ecological Quality of Streams and Rivers throughout Europe using Benthic Macroinvertebrates (Acronym: AQEM)". This project targets is towards the development an assessment procedure for the ecological quality of streams and rivers in Europe. So for this case study on heavily modified water bodies also a river was chosen, to apply this new AQEM procedure, defining the ecological status. • This case study is carried out as a part of a three years research project financed by the German Department of Research and Development, “MAKEF”, on the development of methods and tools for the designation of heavily modified water bodies in the catchment areas of Ruhr and Mulde. 3.2 General Remarks The River Ruhr, a tributary of the River Rhine, is situated in the midwestern part of Germany with a stream length of 219.2 km. The major part of the Ruhr catchment is part of ecoregion 9 (central highlands), while the mouth and the north western tributaries belong to ecoregion 14 (central plains). (see map 3.2.-1 for the location in the ecoregions). The "Ruhrgebiet" located in the western part of the River Ruhr catchment is one of the largest and densest industrial centres in Europe. In the 18th and 19th century cities like Bochum, Essen, Mülheim, and Duisburg developed along the River Ruhr as a consequence of coal mining and steel production. While about 2.2 million people inhabit the Ruhr catchment, the water of the River Ruhr serves as a water supply for 5.2 million people, with the consequence of a water transfer of about 300 Mio. m³/a to the catchments of the rivers Emscher, Lippe, Wupper, and Ems. Map 3.2-1 Catchment of the River Ruhr in the system of ecoregions 9 In the eastern part of the catchment agriculture and forestry form the dominating land uses. 14 reservoirs with a total volume of 473.6 million m³ were built in this area to regulate the flow and to guarantee a sufficient water quantity even under low flow conditions,. Due to organisational reasons (assignment of this research project to an EU-HMW subgroup) the main impact factor on the ecological quality of the Ruhr River had to be chosen preliminarily: the supply of drinking water for 5.2 million inhabitants and the water supply for industrial use. In consequence the case study on the River Ruhr is assigned to the impact group "water supply" with dams, interrupted longitudinal continuum and modified high and low flow conditions. Together with the impact group "hydro-power generation" this impact group forms the EU-HMW subgroup No. 1. (In fact, the dams and weirs in the River Ruhr are used for hydro-power generation as well, producing 162 million kW/a).

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