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Congress: 2008
Author(s): Malte Grossmann, H. Behrendt, H. Gömann, P.Kreins, C. Sartorius
1 TU Berlin, Institute of Landscape and Environmental Planning, Dept. of Landscape Economics, EB 4-2, Straße des 17 Juni 145, 10623 Berlin, 2 Leibniz - Institut für Gewässerökologie und Binnenfischerei, Berlin 3 Bundesforsc

Keyword(s): water quality, global change, nutrients, cost-effectiveness analysis, transboundary river basin management
AbstractThe paper will report on the results of the approach to the economic assessment and modeling of water quality management adopted within the GLOWA Elbe project, which is part of the BMBF funded Program “Global Change of the Hydrological Cycle”. The primary aim of this project component is to analyze the implications of socio-economic and climatic dimensions of global change for management strategies to improve water quality at the scale of a large river basin. This is of particular relevance in the context of the European Water Framework Directive (WATECO, 2002), which requires the development of a cost-effective program of measures to achieve a good ecological status of water bodies by the year 2015. In the process of specification, potential exogenous developments of key driving forces which may impact the reduction and financial effort required to achieve these goals are to be taken into account. Beyond the Water Framework Directive, there are further political commitments to reduce nutrient load to the North Sea emanating from the Elbe Basin. The GLOWA-Elbe impact assessment methodology is the basis for an actor-oriented, river basin approach adopted in the subproject. Water management options are developed and assessed with involvement of stakeholders from water management authorities. Nutrient emissions and retention in river systems are modeled with the help of a well tested and widely applied model MONERIS (cf. Behrendt et al., 1999). The existing model was extended to include components which describe potential measures with associated costs and enable a cost-effectiveness analysis. Least cost solutions can be found with the help of a minimization routine. Advantages of an integrated ecohydrologic-economic model are (a) a consistent coverage of the complete Elbe Basin (b) inclusion of the cumulative downstream effects of measures including the retention in the river system itself (c) inclusion of interaction effects of combinations of measures. The developed goal indicators relate to (a) the water quality class in each sub basin and river stretch of the main river, based on the relation between P concentration and Chlorophyll a production, and (b) total nutrient export into the coastal sea. The included set of measures covers all major nutrient pathways and includes improvements in the waste water treatment and sewerage system, measures to regulate soil erosion, drainage and nutrient surplus in agriculture. Also included are measures that enhance the nutrient retention capacity of lowland fen and floodplain wetlands. Simple cost functions suited for the level of available data have been developed, which build on available economic assessment of measures (cf. Interviews, 2004; Böhm, 2002). Policy measures which entail non-marginal changes in agricultural production are calculated externally on the level of NUTS-3 administrative units using agricultural sector models for German and Czech Republic (cf. Gömann et al., 2004). Results indicate that surface water quality improvements within the basin have to focus on a reduction of phosphorous load, as this is the limiting factor. The reduction in phosphorous load required to actually achieve concentrations in the Elbe main river corresponding to a “good status” will require substantial effort in upstream basins. These go beyond the requirements within each sub basin taken alone. Cost- effectiveness ratios for single type measures and reduction potential vary widely between different sub basins. Key factors are related to landscape characteristics and a historically disparate development of waste water treatment between East and West German states and the Czech Republic. Differentials in cost effectiveness and reduction potential indicate both the necessity and the magnitude of cooperation benefits to be gained from a basin wide coordinated approach to nutrient reduction in contrast to a sub basin by sub basin approach. Finally an analysis of the stability of results under the conditions of different GLOWA Elbe Baseline scenarios regarding the key drivers (climate, European agricultural policy, demographic and economic development, the development of water treatment technologies) will be presented.
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