The Narew River Basin: A model for the sustainable management of agriculture, nature and water supply

摘要

This thesis is a search for a method of environmental management that may lead to sustainable development in North-eastern Poland and the Warsaw region. The methods studied in this thesis provide the components of a decision support system for managing the water quality of the Narew River Basin.udThe basin is characterised by high quality environmental, biological and cultural conditions. It has also the potential to solve the problems concerning the drinking water supply for Warsaw. The Narew River carries sufficient amounts of good quality water and therefore has the potential to solve these problems. Sustainability is defined as maintaining a high quality source for drinking water preparation while preserving of the present nature and landscape. Riveru92s water quality is the crucial aspect connecting land use, nature and drinking water. udThe created decision support system consists of an integrated model that incorporates the relevant elements of the land use u96 surface water u96 aquatic ecosystem cause-and-effect chain. The system was built and evaluated in a sequence of steps.udFirst, the sufficient data for modelling and studying different scenarios were collected. The database contains information on land use, water quality and quantity, and vegetation characteristics.udSecond, the integrated management tool (IMT) was built. IMT consists of three hierarchically linked modules that: compute nutrient emissions loads to surface waters (NULAM), model in-stream nutrient changes (STREAMPLAN) and assess response of aquatic species to changes in nutrient concentrations (INCORS). udNULAM is a lumped model, which calculates nutrient losses for each land use type and each type of livestock found in the catchment using the export coefficient approach. The results from this model were input to water quality model. STREAMPLAN uses one-dimensional, linear and steady state approach. Subsequently, the nutrient concentrations generated in the STREAMPLAN were used an input for an empirical statistical model. INCORS is a logistic regression model that describes the response of plant species to changes in nutrient concentrations. All three modules were calibrated for growing season low-flow conditions and linked together within GIS.udFinally, the IMT was used to study scenarios for possible development. In the basin two different development schemes may be expected when looking at the present political situation. The first considers Poland joining the European Union, which may lead to a rapid intensification of agricultural production and associated eutrophication. The second scenario explores the idea of sustainable development following current ideas for transition towards ecological farming in areas with high quality nature. udThe most important conclusion of the scenario study is that straightforward implementation of the EU agricultural limits may result in double the nutrient emissions, which in turn may deteriorate surface water quality and river ecosystems. Such a development will disqualify the basin as a suitable source for drinking water production. The second scenario showed that extensive agriculture might reduce nutrient emissions by half, which improves quality of surface waters and will preserve biodiversity of aquatic vegetation. In this case water of the Narew River will be the best source of raw material for drinking water production.udThe thesis illustrates the value of the IMT by demonstrating the results of two extreme development strategies for the basin. Therefore, the tool gives policy makers, local authorities and society an idea of the range within which the basin may develop. GIS-based approach permitted the development of spatially distributed scenarios dependent on present and expected dominant land use functions.udThe presented study presented is but one of a few for which a large catchment decision support system has been developed. It demonstrates that sustainability can be defined in operational variables for water managers and land use planners. The IMT complies with a standard of the European Water Framework Directive which requires all EU-member states to develop methods enabling them to quantify the effects of changes in land use and water management on ecosystems