@article{ISI:000246812000024,
  abstract = {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.},
  added-at = {2008-07-15T09:29:13.000+0200},
  author = {Pohlert, T. and Breuer, L. and Huisman, J. A. and Frede, H. G},
  biburl = {http://www.bibsonomy.org/bibtex/21e940ccf0432c8067a30713035c4891d/resourcemgmt},
  interhash = {0bc89a051de326bae5f43246acbb5099},
  intrahash = {1e940ccf0432c8067a30713035c4891d},
  issn = {1027-5606},
  journal = {HYDROLOGY AND EARTH SYSTEM SCIENCES},
  keywords = {IFZ imported},
  number = 2,
  pages = {997-1011},
  timestamp = {2008-07-15T09:29:13.000+0200},
  title = {Assessing the model performance of an integrated hydrological and biogeochemical model for discharge and nitrate load predictions},
  volume = 11,
  year = 2007
}

@article{ISI:000256958700027,
  abstract = {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.},
  added-at = {2008-07-15T09:29:13.000+0200},
  author = {Froehlich, Holger L. and Breuer, Lutz and Frede, Hans-Georg and Huisman, Johan A. and Vache, Kelhe B.},
  biburl = {http://www.bibsonomy.org/bibtex/2c59f28094c92755ca4407f5921a237cb/resourcemgmt},
  interhash = {92f435d1a628bee0094dc1d2580aaa55},
  intrahash = {c59f28094c92755ca4407f5921a237cb},
  issn = {0885-6087},
  journal = {HYDROLOGICAL PROCESSES},
  keywords = {IFZ catchment_heterogeneity characterization patterns principle_component_analysis snapshot_sampling spatiotemporal stream_water_chemistry water_source},
  number = 12,
  pages = {2028-2043},
  timestamp = {2008-07-15T09:29:13.000+0200},
  title = {Water source characterization through spatiotemporal patterns of major, minor and trace element stream concentrations in a complex, mesoscale German catchment},
  volume = 22,
  year = 2008
}

@article{ISI:000250063700001,
  abstract = {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.},
  added-at = {2008-07-15T09:29:13.000+0200},
  author = {Reichenberger, Stefan and Bach, Martin and Skitschak, Adrian and Frede, Hans-Georg},
  biburl = {http://www.bibsonomy.org/bibtex/2f845e5cac26e5f25551e0eb26d993155/resourcemgmt},
  interhash = {6c13ca8d7642d668f448862246e9ad61},
  intrahash = {f845e5cac26e5f25551e0eb26d993155},
  issn = {0048-9697},
  journal = {SCIENCE OF THE TOTAL ENVIRONMENT},
  keywords = {IFZ diffuse_sources effectiveness mitigation_measures pesticides point_sources practicability risk},
  number = {1-3},
  pages = {1-35},
  timestamp = {2008-07-15T09:29:13.000+0200},
  title = {Mitigation strategies to reduce pesticide inputs into ground- and surface water and their effectiveness; A review},
  volume = 384,
  year = 2007
}

@article{ISI:000246189800003,
  abstract = {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.},
  added-at = {2008-07-15T09:29:13.000+0200},
  author = {Pohlert, T. and Huisman, J. A. and Breuer, L. and Frede, H. G},
  biburl = {http://www.bibsonomy.org/bibtex/2770adc4c4179f6bd7dc3b131156c8730/resourcemgmt},
  interhash = {4a11c6120abdae7008129d049263a0c6},
  intrahash = {770adc4c4179f6bd7dc3b131156c8730},
  issn = {0304-3800},
  journal = {ECOLOGICAL MODELLING},
  keywords = {IFZ N-budget denitrification lysimeter mineralisation nitrification sensitivity_analysis uncertainty_estimation},
  number = {3-4},
  pages = {215-228},
  timestamp = {2008-07-15T09:29:13.000+0200},
  title = {Integration of a detailed biogeochemical model into SWAT for improved nitrogen predictions - Model development, sensitivity, and GLUE analysis},
  volume = 203,
  year = 2007
}