BibSonomyburst/user/resourcemgmt/IFZBibSonomy RSS feed for /user/resourcemgmt/IFZ2012-02-16T09:58:41+01:00http://www.bibsonomy.org/bibtex/21e940ccf0432c8067a30713035c4891d/resourcemgmtresourcemgmt2008-07-15T09:29:13+02:00IFZ imported <span class="authorEditorList"><a href="/author/Pohlert">T. Pohlert</a>, <a href="/author/Breuer">L. Breuer</a>, <a href="/author/Huisman">J. A. Huisman</a>, and <a href="/author/Frede">H. G Frede</a> </span><em>HYDROLOGY AND EARTH SYSTEM SCIENCES</em> <em>11(2):997-1011</em> (<em>2007</em>)Tue Jul 15 09:29:13 CEST 2008HYDROLOGY AND EARTH SYSTEM SCIENCES2997-1011Assessing the model performance of an integrated hydrological and biogeochemical model for discharge and nitrate load predictions112007IFZ imported In this study, we evaluate the performance of the SWAT-N model, a modified version of the widely used SWAT version, for discharge and nitrate predictions at the mesoscale Dill catchment (Germany) for a 5-year period. The underlying question is, whether the model efficiency is sufficient for scenario analysis of land-use changes on both water quantity and quality. The Shuffled Complex Evolution (SCE-UA) algorithm is used to calibrate the model for daily discharge at the catchments outlet. Model performance is assessed with a split-sampling as well as a proxy-basin test using recorded hydrographs of four additional gauges located within the catchment. The efficiency regarding nitrate load simulation is assessed without further calibration on a daily, log-daily, weekly, and monthly basis as compared to observations derived from an intensive sampling campaign conducted at the catchments outlet. A new approach is employed to test the spatial consistency of the model, where simulated longitudinal profiles of nitrate concentrations were compared with observed longitudinal profiles. It is concluded that the model efficiency of SWAT-N is sufficient for the assessment of scenarios for daily discharge predictions. SWAT-N can be employed without further calibration for nitrate load simulations on both a weekly and monthly basis with an acceptable degree of accuracy. However, the model efficiency for daily nitrate load is insufficient, which can be attributed to both data uncertainty (i.e. point-source effluents and actual farming practise) as well as structural errors. The simulated longitudinal profiles meet the observations reasonably well, which suggests that the model is spatially consistent.http://www.bibsonomy.org/bibtex/2c59f28094c92755ca4407f5921a237cb/resourcemgmtresourcemgmt2008-07-15T09:29:13+02:00IFZ catchment_heterogeneity characterization patterns principle_component_analysis snapshot_sampling spatiotemporal stream_water_chemistry water_source <span class="authorEditorList"><a href="/author/Froehlich">Holger L. Froehlich</a>, <a href="/author/Breuer">Lutz Breuer</a>, <a href="/author/Frede">Hans-Georg Frede</a>, <a href="/author/Huisman">Johan A. Huisman</a>, and <a href="/author/Vache">Kelhe B. Vache</a> </span><em>HYDROLOGICAL PROCESSES</em> <em>22(12):2028-2043</em> (<em>2008</em>)Tue Jul 15 09:29:13 CEST 2008HYDROLOGICAL PROCESSES122028-2043Water source characterization through spatiotemporal patterns of major, minor and trace element stream concentrations in a complex, mesoscale German catchment222008IFZ catchment_heterogeneity characterization patterns principle_component_analysis snapshot_sampling spatiotemporal stream_water_chemistry water_source The link between spatiotemporal patterns of stream water chemistry and catchment characteristics for the mesoscale Dill catchment (692 km(2)) in Germany is explored to assess the catchment scale controls on water quality and to characterize water sources. In order to record the spatiotemporal pattern, �snapshot sampling� was applied during low, mean and high flow, including 73 nested sites throughout the catchment. Water samples were analysed for the elements Li, B, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Rb, Sr, Mo, Ba, Ph and U using inductively-coupled-plasma mass spectrometry, and for electric conductivity and pH. Principle component analysis and hierarchical cluster analysis were used to find typical element associations and to group water samples according to their hydrochemical fingerprints. This revealed regional hydrochemical patterns of water quality which were subsequently related to catchment attributes to draw conclusions about the controls on stream chemistry. It was found that various lithologic signals and anthropogenic point source inputs controlled the base flow hydrochemistry. During increased flows, stream waters were diluted causing additional hydrochemical variability in response to heterogeneous precipitation inputs and differences in aquifer storage capacities. The hydrochemical patterns further displayed in-stream mixing of waters. This implied, that stream waters could be apportioned to the identified water sources throughout the catchment. The basin-wide hydrochemical variability has the potential to outrange the tracer signatures typically inferred in studies at the hillslope scale and is able to strongly influence the complexity of the catchment output. Both have to be considered for further catchment scale tracer and modelling work. Despite the likelihood of non-conservative behaviour, the minor and trace elements enhanced the rather qualitative discrimination of the various groundwater types, as the major cations were strongly masked by point source inputs. Copyright (C) 2007 John Wiley & Sons, Ltd.http://www.bibsonomy.org/bibtex/2f845e5cac26e5f25551e0eb26d993155/resourcemgmtresourcemgmt2008-07-15T09:29:13+02:00IFZ diffuse_sources effectiveness mitigation_measures pesticides point_sources practicability risk <span class="authorEditorList"><a href="/author/Reichenberger">Stefan Reichenberger</a>, <a href="/author/Bach">Martin Bach</a>, <a href="/author/Skitschak">Adrian Skitschak</a>, and <a href="/author/Frede">Hans-Georg Frede</a> </span><em>SCIENCE OF THE TOTAL ENVIRONMENT</em> <em>384(1-3):1-35</em> (<em>2007</em>)Tue Jul 15 09:29:13 CEST 2008SCIENCE OF THE TOTAL ENVIRONMENT1-31-35Mitigation strategies to reduce pesticide inputs into ground- and surface water and their effectiveness; A review3842007IFZ diffuse_sources effectiveness mitigation_measures pesticides point_sources practicability risk In this paper, the current knowledge on mitigation strategies to reduce pesticide inputs into surface water and groundwater, and their effectiveness when applied in practice is reviewed. Apart from their effectiveness in reducing pesticide inputs into ground and surface water, the mitigation measures identified in the literature are evaluated with respect to their practicability. Those measures considered both effective and feasible are recommended for implementing at the farm and catchment scale. Finally, recommendations for modelling are provided using the identified reduction efficiencies. Roughly 180 publications directly dealing with or being somehow related to mitigation of pesticide inputs into water bodies were examined. The effectiveness of grassed buffer strips located at the lower edges of fields has been demonstrated. However, this effectiveness is very variable, and the variability cannot be explained by strip width alone. Riparian buffer strips are most probably much less effective than edge-of-field buffer strips in reducing pesticide runoff and erosion inputs into surface waters. Constructed wetlands are promising tools for mitigating pesticide inputs via runoff/erosion and drift into surface waters, but their effectiveness still has to be demonstrated for weakly and moderately sorbing compounds. Subsurface drains are an effective mitigation measure for pesticide runoff losses from slowly permeable soils with frequent waterlogging. For the pathways drainage and leaching, the only feasible mitigation measures are application rate reduction, product substitution and shift of the application date. There are many possible effective measures of spray drift reduction. While sufficient knowledge exists for suggesting default values for the efficiency of single drift mitigation measures, little information exists on the effect of the drift reduction efficiency of combinations of measures. More research on possible interactions between different drift mitigation measures and the resulting overall drift reduction efficiency is therefore indicated. Point-source inputs can be mitigated against by increasing awareness of the farmers with regard to pesticide handling and application, and encouraging them to implement loss-reducing measures of ��best management practice". In catchments dominated by diffuse inputs at least in some years, mitigation of point-source inputs alone may not be sufficient to reduce pesticide loads/concentrations in water bodies to an acceptable level. (C) 2007 Published by Elsevier B.V.http://www.bibsonomy.org/bibtex/2770adc4c4179f6bd7dc3b131156c8730/resourcemgmtresourcemgmt2008-07-15T09:29:13+02:00IFZ N-budget denitrification lysimeter mineralisation nitrification sensitivity_analysis uncertainty_estimation <span class="authorEditorList"><a href="/author/Pohlert">T. Pohlert</a>, <a href="/author/Huisman">J. A. Huisman</a>, <a href="/author/Breuer">L. Breuer</a>, and <a href="/author/Frede">H. G Frede</a> </span><em>ECOLOGICAL MODELLING</em> <em>203(3-4):215-228</em> (<em>2007</em>)Tue Jul 15 09:29:13 CEST 2008ECOLOGICAL MODELLING3-4215-228Integration of a detailed biogeochemical model into SWAT for improved nitrogen predictions - Model development, sensitivity, and GLUE analysis2032007IFZ N-budget denitrification lysimeter mineralisation nitrification sensitivity_analysis uncertainty_estimation In this study, the Soil and Water Assessment Tool (SWAT) was extended with algorithms from a detailed nitrogen turnover model to enhance the model performance with regard to the prediction of nitrogen leaching. The new model, which is further referred to as SWAT-N, includes algorithms for decomposition, growth of nitrifying bacteria, nitrification, nitrificatory as well as denitrificatory N-emissions, N-uptake by plants and N transport due to water fluxes. The model was tested with a lysimeter dataset of a long term fertilisation experiment including crop rotation conducted in Eastern Germany. A regression-based global sensitivity analysis was employed to test the impact of the new implemented parameters on the sensitivity of various model output variables. The rate coefficient for decomposition, the pH-value, and the porous fraction from which anions are excluded were identified as the most important parameters controlling nitrogen leaching and gaseous nitrogen emissions. A generalised likelihood uncertainty estimation (GLUE) was conducted afterwards to calculate conditioned prediction intervals for each simulated time step. A maximum model efficiency after [Nash, J.E., Sutcliffe, J.V., 1970. River flow forecasting through conceptual models. Part 1. A discussion of principles. J. Hydrol. 10, 282-290] of 0.4 could be achieved for the simulation of monthly nitrogen leaching. It is concluded, that the implemented algorithms enhance the model performance of SWAT, since the previous SWAT version failed to accurately simulate nitrogen leaching at the investigated site. (C) 2006 Elsevier B.V. All rights reserved.