Assessing the impact of changes in land use and management practices on the diffuse pollution and retention of nitrate in a riparian floodplain. Sci Total Environ

Centre for Sustainable Water Management, Lancaster Environment Centre, Lancaster, United Kingdom.
Science of The Total Environment (Impact Factor: 4.1). 02/2008; 389(1):149-64. DOI: 10.1016/j.scitotenv.2007.08.057
Source: PubMed


In many European lowland rivers and riparian floodplains diffuse nutrient pollution is causing a major risk for the surface waters and groundwater to not achieve a good status as demanded by the European Water Framework Directive. In order to delimit the impact of diffuse nutrient pollution substantial and often controversial changes in landuse and management are under discussion. In this study we investigate the impact of two complex scenarios considering changes in landuse and land management practices on the nitrate loads of a typical lowland stream and the riparian groundwater in the North German Plains. Therefore the impacts of both scenarios on the nitrate dynamics, the attenuation efficiency and the nitrate exchange between groundwater and surface water were investigated for a 998.1 km(2) riparian floodplain of the Lower and Central Havel River and compared with the current conditions. Both scenarios target a substantial improvement of the ecological conditions and the water quality in the research area but promote different typical riparian landscape functions and consider a different grade of economical and legal feasibility of the proposed measures. Scenario 1 focuses on the optimisation of conservation measures for all natural resources of the riparian floodplain, scenario 2 considers measures in order to restore a good status of the water bodies mainly. The IWAN model was setup for the simulation of water balance and nitrate dynamics of the floodplain for a perennial simulation period of the current landuse and management conditions and of the scenario assumptions. The proposed landuse and management changes result in reduced rates of nitrate leaching from the root zone into the riparian groundwater (85% for scenario 1, 43% for scenario 2). The net contributions of nitrate from the floodplain can be reduced substantially for both scenarios. In case of scenario 2 a decrease by 70% can be obtained. For scenario 1 the nitrate exfiltration rates to the river drop even below the infiltration rates from the river, the riparian floodplain in that scenario represents a net sink for river derived nitrate. As the nitrate contributions from the investigated riparian floodplain represent only a small proportion of the total nitrate loads within the river (1% p.a.) the overall impact of the scenario measures on the nitrate loads at the river outlet remains small. However, during the ecologically most sensitive summer periods under current conditions nitrate contributions from the riparian groundwater of the Lower and Central Havel River (which covers only 5% of the area of the Havel catchment) represent more than 20% of the river loads. By the implementation of the investigated landuse changes within the research area the groundwater derived nitrate contributions could be halved to only 10% during summer baseflow conditions.

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Available from: Axel Bronstert, Oct 07, 2015
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    • "In particular, riparian zones perform many ecological functions, including preserving biodiversity and purifying polluted waters (Batlle-Aguilar et al., 2012). However, they are also fragile systems and can be modified easily by land use change (Hlubikova et al., 2014; Krause et al., 2008). Over the past century, the scale and intensity of land use and exploitation have increased dramatically, particularly in arid regions. "
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    ABSTRACT: We analyzed the impacts of LUCC on soil properties in the riparian area zones of desert oasis.•The combination of soil experiment with RS images in a long time scale•Soil moisture and soil organic carbon can be explained by LUCC well.•Soil nutrients have no significant correlation with LUCC.
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    • "Mathematical models are broadly used in practice to tackle these policy questions through scenario analyses (Gevaert et al. 2009). Models help identifying measures to achieve a target ecological status, by taking into account possible management options (Kersebaum et al. 2003; Chaplot et al. 2004; Lohmann et al. 2007; Krause et al. 2008; Volk et al. 2009; Scheringer 2009). For example, Brock et al. (2006) assessed ecological protection goals for pesticides risk in surface waters and proposed considering multiple emission scenarios when evaluating ecotoxicological effects in support of EU policies; Zukowska et al. (2005) modeled fate and transport of selected POPs in the Vistula catchment investigating different scenarios of economic development and regulations; Gevaert et al. (2009) discussed scenarios to illustrate the usefulness of models in the implementation of the WFD for 2 priority substances in representative Western European rivers; Holzkämper et al. (2012) proposed the integrated catchment management as a tool to evaluate management options under high complexity and uncertainty; Volk et al. (2009) assessed river water quality depending on land‐use scenarios; the risk of chemicals has been considered for the Mediterranean region under crop‐specific (Ramos et al. 2007) and water scarcity (Petrovic et al. 2011) scenarios. "
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    • "One study is summarised here to illustrate the potential value of groundwater flow models for ecological investigations. Krause et al. (2008) set up a three-dimensional model of the alluvial aquifer near the Havel River, Germany. MODFLOW was used to simulate groundwater flow and aquifer-river exchange. "
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