The overarching aim of the third phase of the GLOWA Elbe project is to understand the risks as well as the options which arise from the global change for the catchment area of the Elbe and to submit the results to the decision makers of the region for implement their aims of a sustainable management.
The target for Phase II was redefined and is as follows:
Analysis of the regional effects of global change in the Elbe Basin and the resulting policy options for surface water management. GLOWA Elbe II covers processes in the Czech and German parts of the Elbe basin, but policy options and recommendations are only analysed or made for the German part.
Among the spectrum of activities, special attention is given not only to the effects of climate change, but also to analysis of the impacts of new technologies, socio-economic change processes, land-use change and extreme events. Policy options for surface water availability and quality are formulated, analysed and assessed. The formulation of alternative policy options for water availability and quality is based on previous investigations of the potential for conflict under status quo conditions and under changes to the status quo through potential climate-change impacts. The expected final result of GLOWA Elbe II will be specific policy options for the conflicting areas of water availability and quality, and overarching recommendations for adaptation of surface water management to global change.
In various depths of analysis the scenario studies of the Elbe cachement region illustrate the water balance’s sensitivity and vulnerability towards a continued decrease of precipitation in the light of current climate change. Preceding studies of possible climate modifications have shown that both further temperature increase and corresponding precipitation decrease are plausible scenarios for the German sub-region.
According to this scenario climate change may accelerate structural change in the agricultural sector. Land area at the disposal for alternative land use will increase. If continental conditions in the lee areas of low mountain ranges (Harz, Thuringian Forest, and Erz Mountains) are accentuated further, the intensively cultivated areas in the Magdeburger Börde, Thüringer Basin, and Leipziger Lowland Plain will also be affected. A decrease in precipitation alone will not fundamentally alter the water quality in the Elbe Region. Declining substance deposition and decreasing nutrient dilution in receiving waters seem to compensate each other. Comparing changing scopes of the overall concept’s components ”preserving competitive capacity of agricultural production” and ”disburdening water balance” within the postulated global change shows that the former will tend to become narrower, the latter will tend to broaden.
A climate related reduction of water availability greatly challenges flooding remnant lignite mining pits in the Lausitz and successfully meeting the associated restoration tasks (creating the Lausitzer Lake District). Shutting down lignite strip mining that also entails tapering off water channeled into the Spree’s river network in the course of mine draining worsens the problem. The decreasing water availability is associated with the loss of wetlands and a mounting mineralization of peat soils in the Spree Forest. Further impacts include a reduction of the Spree inflow into Berlin during summer months and also a potential drop of water quality in Berlin’s water bodies. Modifying the flooding regimes of remnant lignite mining pits and transferring water from other river systems can abate the negative effects of the problems indicated. Negative effects on water quality and guaranteeing supplies would especially be cut back by reducing power plant capacities and applying modern cooling technologies.
In order to achieve this target the following questions – looking at the period up to about the year 2050 – will be examined: