257-Long-Term Integrated Water Management in the German Elbe River Basin.

Abstract

A general Integration Methodology and Approach management in large river basins. Main steps of the approach are: 1. Problem description and goals definition 2. Conceptualisation 3. Scenario definition and alternative management design 4. Simulation and estimation of effects/impacts 5. Evaluation 6. Comparison and negotiation. (IMA) has been developed to investigate multipurpose Stakeholders and decision makers are involved in all steps of the approach. The approach is now applied in the whole Elbe river basin covering the Czech Republic and Germany (148000 km2, about 1/3 Czech, 2/3 Germany). Results will be presented next year. To illustrate how the approach works selected results from an earlier study in a German tributary river basin, the Spree-Havel basin (24000 km2), in particular the Spree river basin upstream Berlin (6171 km2), will be presented here. In this river basin, the following critical conditions are given: • limited water availability, in particular in the vegetation season (summer) • increasing water demand in urban areas and industrial regions • insufficient nature protection in many wetlands • irregular winter floods • complex water management conditions. Basis for the detailed analysis has been a complex water balance and management model containing 190 users (industries, municipalities, wetlands, etc.), 122 balance points, 14 reservoirs, 50 dynamical elements (modules) representing special elements and functions in the basin (e.g. water transfers, open pit mines) and about 200 reference points where results can be registered to evaluate the investigated scenarios. In the end, a control strategy for the reservoirs, water transfers and water uses is selected, that fulfils best over time the demands throughout the basin. As an example, it should be mentioned that a sufficient water supply for the Berlin area could only be achieved by constructing a new reservoir in the upper Spree basin and by operating the system on a continuous basis considering the water demands of all users in the basin. A general conclusions from the study is that in dry periods (summers) special measures are required to provide enough water for the surface water system of Berlin, to the wetlands of the Spreewald and in the upper Spree for the refilling of the open pit mines to act against their acidification.