The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Anne Lausten Hansen - One of the best experts on this subject based on the ideXlab platform.
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Importance of including small‐scale Tile Drain discharge in the calibration of a coupled groundwater‐surface water catchment model
Water Resources Research, 2013Co-Authors: Anne Lausten Hansen, Jens Christian Refsgaard, Britt Christensen, K H JensenAbstract:[1] To use a catchment-scale model to delineate areas with high and low denitrification capacities in the saturated zone of a catchment, the model must have an accurate spatial description of both general large-scale flow patterns on catchment scale and small-scale flow patterns locally within the catchment. In this study, a coupled groundwater-surface water model based on the MIKE SHE code was developed for the 4.7 km2 Lillebaek catchment in Denmark, where Tile Drain flow is a major contributor to the stream discharge. The catchment model was calibrated in several steps by incrementally including the observation data into the calibration to see the effect on model performance of including diverse data types, especially Tile Drain discharge. For the Lillebaek catchment, measurements of hydraulic head, daily stream discharge, and daily Tile Drain discharge from five small (1–4 ha) Drainage areas exist. The results showed that including Tile Drain data in the calibration of the catchment model improved its general performance for hydraulic heads and stream discharges. However, the model failed to correctly describe the local-scale dynamics of the Tile Drain discharges, and, furthermore, including the Drain data in the calibration did not improve the small-scale spatial dynamics. This is mainly believed to be caused by the model's inadequate simulation of local spatial dynamics in hydraulic heads, which we argue is likely due to the lack of sufficient heterogeneity in the geological model.
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importance of including small scale Tile Drain discharge in the calibration of a coupled groundwater surface water catchment model
Water Resources Research, 2013Co-Authors: Anne Lausten Hansen, Jens Christian Refsgaard, Britt Christensen, K H JensenAbstract:[1] To use a catchment-scale model to delineate areas with high and low denitrification capacities in the saturated zone of a catchment, the model must have an accurate spatial description of both general large-scale flow patterns on catchment scale and small-scale flow patterns locally within the catchment. In this study, a coupled groundwater-surface water model based on the MIKE SHE code was developed for the 4.7 km2 Lillebaek catchment in Denmark, where Tile Drain flow is a major contributor to the stream discharge. The catchment model was calibrated in several steps by incrementally including the observation data into the calibration to see the effect on model performance of including diverse data types, especially Tile Drain discharge. For the Lillebaek catchment, measurements of hydraulic head, daily stream discharge, and daily Tile Drain discharge from five small (1–4 ha) Drainage areas exist. The results showed that including Tile Drain data in the calibration of the catchment model improved its general performance for hydraulic heads and stream discharges. However, the model failed to correctly describe the local-scale dynamics of the Tile Drain discharges, and, furthermore, including the Drain data in the calibration did not improve the small-scale spatial dynamics. This is mainly believed to be caused by the model's inadequate simulation of local spatial dynamics in hydraulic heads, which we argue is likely due to the lack of sufficient heterogeneity in the geological model.
Rao S Govindaraju - One of the best experts on this subject based on the ideXlab platform.
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A process‐based transfer function approach to model Tile‐Drain hydrographs
Hydrological Processes, 2020Co-Authors: Mazdak Arabi, Jennifer S Stillman, Rao S GovindarajuAbstract:Tile-Drain response to rainfall events is determined by unsaturated vertical flow to the water table, followed by horizontal saturated water movement. In this study, unsaturated vertical movement from the redistribution of water is modelled using a sharp-front approximation, and the saturated horizontal flow is modelled by an approximate solution to the Boussinesq equation. The unsaturated flow component models the fast response that is associated with the presence of preferential flow paths. By convoluting the responses of the two components, a transfer function is developed that predicts Tile-Drain response to unit amounts of infiltrated water. It is observed that the unsaturated flow component can be cast in a form that is linear in a power function of the infiltrated depth. Since the approach is process based, model parameter definitions are easily identified with soil properties at the field scale. Furthermore, it is demonstrated that the transfer function model parameters can be estimated from moment analysis. Using superposition, the transient Tile-Drain response to arbitrary amounts of infiltrated water can be constructed. Comparison with data measured from the Water Quality Field Station show that this approach provides a promising method for generating Tile-Drain response to rainfall events. Copyright © 2006 John Wiley & Sons, Ltd.
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a process based transfer function approach to model Tile Drain hydrographs
Hydrological Processes, 2006Co-Authors: Mazdak Arabi, Jennifer S Stillman, Rao S GovindarajuAbstract:Tile-Drain response to rainfall events is determined by unsaturated vertical flow to the water table, followed by horizontal saturated water movement. In this study, unsaturated vertical movement from the redistribution of water is modelled using a sharp-front approximation, and the saturated horizontal flow is modelled by an approximate solution to the Boussinesq equation. The unsaturated flow component models the fast response that is associated with the presence of preferential flow paths. By convoluting the responses of the two components, a transfer function is developed that predicts Tile-Drain response to unit amounts of infiltrated water. It is observed that the unsaturated flow component can be cast in a form that is linear in a power function of the infiltrated depth. Since the approach is process based, model parameter definitions are easily identified with soil properties at the field scale. Furthermore, it is demonstrated that the transfer function model parameters can be estimated from moment analysis. Using superposition, the transient Tile-Drain response to arbitrary amounts of infiltrated water can be constructed. Comparison with data measured from the Water Quality Field Station show that this approach provides a promising method for generating Tile-Drain response to rainfall events. Copyright © 2006 John Wiley & Sons, Ltd.
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a semi analytical model for transient flow to a subsurface Tile Drain
Journal of Hydrology, 2006Co-Authors: Jennifer S Stillman, Nathan W Haws, Rao S GovindarajuAbstract:The goal of this paper is to develop and test a semi-analytical model for event-based transient flow to a subsurface Tile Drain. A sharp-front theory was used to describe redistribution of infiltrated water in the vadose zone. New approximate analytical solutions in terms of Fourier series were sought for the Boussinesq equation describing subsurface saturated flow subject to time-dependent recharge. Both one and two-term solutions of the series approximation were compared with observed Tile hydrograph data from the Purdue Water Quality Field Station (WQFS) in West Lafayette, Indiana. In general, the models were able to capture the peaks of the Tile-Drain hydrographs, as well as the times-to-peak and the times-of-initial-response to rainfall events. The models performed particularly well for rainfall events with single-burst hyetographs, and in the prediction of the first hydrograph peak from multiple-burst hyetographs, though subsequent peaks could not be captured as well. A further comparison of results from the one-term model with those from HYDRUS 2D suggested that the one-term model is adequate for estimating transient flow to a Tile Drain. The solution developed here holds promise for extension to larger watersheds where the hydrology is governed by Tile Drains.
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a process based transfer function approach to model Tile Drain hydrographs
World Water and Environmental Resources Congress 2005, 2005Co-Authors: Mazdak Arabi, Jennifer S Schmidt, Rao S GovindarajuAbstract:Tile Drain response to rainfall events is determined by unsaturated vertical flow to the water table, followed by horizontal saturated water movement. In this study, unsaturated vertical movement from redistribution of water is modeled using a sharp front approximation, while the saturated horizontal flow is modeled by an approximate solution to the Boussinesq equation. The unsaturated flow component models the fast response that is associated with the presence of preferential flow paths. By convoluting the responses of the two components, a transfer function is developed that predicts Tile Drain response to unit amounts of infiltrated water. Since the approach is process-based, model parameter definitions are easily identified with soil properties at the field scale. It was shown that transient Tile Drain response to arbitrary amounts of infiltrated water can be constructed using superposition principles. Comparison with data measured from the Water Quality Field Station show that this approach provides a promising method for generating Tile Drain response to rainfall events.
K H Jensen - One of the best experts on this subject based on the ideXlab platform.
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Importance of including small‐scale Tile Drain discharge in the calibration of a coupled groundwater‐surface water catchment model
Water Resources Research, 2013Co-Authors: Anne Lausten Hansen, Jens Christian Refsgaard, Britt Christensen, K H JensenAbstract:[1] To use a catchment-scale model to delineate areas with high and low denitrification capacities in the saturated zone of a catchment, the model must have an accurate spatial description of both general large-scale flow patterns on catchment scale and small-scale flow patterns locally within the catchment. In this study, a coupled groundwater-surface water model based on the MIKE SHE code was developed for the 4.7 km2 Lillebaek catchment in Denmark, where Tile Drain flow is a major contributor to the stream discharge. The catchment model was calibrated in several steps by incrementally including the observation data into the calibration to see the effect on model performance of including diverse data types, especially Tile Drain discharge. For the Lillebaek catchment, measurements of hydraulic head, daily stream discharge, and daily Tile Drain discharge from five small (1–4 ha) Drainage areas exist. The results showed that including Tile Drain data in the calibration of the catchment model improved its general performance for hydraulic heads and stream discharges. However, the model failed to correctly describe the local-scale dynamics of the Tile Drain discharges, and, furthermore, including the Drain data in the calibration did not improve the small-scale spatial dynamics. This is mainly believed to be caused by the model's inadequate simulation of local spatial dynamics in hydraulic heads, which we argue is likely due to the lack of sufficient heterogeneity in the geological model.
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importance of including small scale Tile Drain discharge in the calibration of a coupled groundwater surface water catchment model
Water Resources Research, 2013Co-Authors: Anne Lausten Hansen, Jens Christian Refsgaard, Britt Christensen, K H JensenAbstract:[1] To use a catchment-scale model to delineate areas with high and low denitrification capacities in the saturated zone of a catchment, the model must have an accurate spatial description of both general large-scale flow patterns on catchment scale and small-scale flow patterns locally within the catchment. In this study, a coupled groundwater-surface water model based on the MIKE SHE code was developed for the 4.7 km2 Lillebaek catchment in Denmark, where Tile Drain flow is a major contributor to the stream discharge. The catchment model was calibrated in several steps by incrementally including the observation data into the calibration to see the effect on model performance of including diverse data types, especially Tile Drain discharge. For the Lillebaek catchment, measurements of hydraulic head, daily stream discharge, and daily Tile Drain discharge from five small (1–4 ha) Drainage areas exist. The results showed that including Tile Drain data in the calibration of the catchment model improved its general performance for hydraulic heads and stream discharges. However, the model failed to correctly describe the local-scale dynamics of the Tile Drain discharges, and, furthermore, including the Drain data in the calibration did not improve the small-scale spatial dynamics. This is mainly believed to be caused by the model's inadequate simulation of local spatial dynamics in hydraulic heads, which we argue is likely due to the lack of sufficient heterogeneity in the geological model.
H P Broers - One of the best experts on this subject based on the ideXlab platform.
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direct measurements of the Tile Drain and groundwater contributions to surface water contamination from field scale concentration patterns in groundwater to catchment scale dynamics in stream water nutrient concentrations
Geophysical Research Abstracts, 2012Co-Authors: F C Van Geer, J C Rozemeijer, Y Van Der Velde, H P BroersAbstract:Enhanced knowledge of water and nutrient pathways in catchments improves the understanding of dynamics in water quality and supports the selection of appropriate water pollution mitigation options. For this study, we physically separated Tile Drain effluent and groundwater discharge from an agricultural field before it entered a 43.5 meter ditch transect. Through continuous discharge measurements and weekly water quality sampling, we directly quantified the flow route contributions to surface water discharge and solute loading. Our multi-scale experimental approach allowed us to relate these measurements to field-scale NO3 concentration patterns in shallow groundwater and to continuous NO3 records at the catchment outlet.
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direct measurements of the Tile Drain and groundwater flow route contributions to surface water contamination from field scale concentration patterns in groundwater to catchment scale surface water quality
Environmental Pollution, 2010Co-Authors: J C Rozemeijer, F C Van Geer, Y Van Der Velde, M F P Bierkens, H P BroersAbstract:Enhanced knowledge of water and solute pathways in catchments would improve the understanding of dynamics in water quality and would support the selection of appropriate water pollution mitigation options. For this study, we physically separated Tile Drain effluent and groundwater discharge from an agricultural field before it entered a 43.5-m ditch transect. Through continuous discharge measurements and weekly water quality sampling, we directly quantified the flow route contributions to surface water discharge and solute loading. Our multi-scale experimental approach allowed us to relate these measurements to field-scale NO 3 concentration patterns in shallow groundwater and to continuous NO 3 records at the catchment outlet. Our results show that the Tile Drains contributed 90-92% of the annual NO 3 and heavy metal loads. Considering their crucial role in water and solute transport, enhanced monitoring and modeling of Tile Drainage are important for adequate water quality management. © 2010 Published by Elsevier Ltd. All rights reserved.
F C Van Geer - One of the best experts on this subject based on the ideXlab platform.
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direct measurements of the Tile Drain and groundwater contributions to surface water contamination from field scale concentration patterns in groundwater to catchment scale dynamics in stream water nutrient concentrations
Geophysical Research Abstracts, 2012Co-Authors: F C Van Geer, J C Rozemeijer, Y Van Der Velde, H P BroersAbstract:Enhanced knowledge of water and nutrient pathways in catchments improves the understanding of dynamics in water quality and supports the selection of appropriate water pollution mitigation options. For this study, we physically separated Tile Drain effluent and groundwater discharge from an agricultural field before it entered a 43.5 meter ditch transect. Through continuous discharge measurements and weekly water quality sampling, we directly quantified the flow route contributions to surface water discharge and solute loading. Our multi-scale experimental approach allowed us to relate these measurements to field-scale NO3 concentration patterns in shallow groundwater and to continuous NO3 records at the catchment outlet.
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direct measurements of the Tile Drain and groundwater flow route contributions to surface water contamination from field scale concentration patterns in groundwater to catchment scale surface water quality
Environmental Pollution, 2010Co-Authors: J C Rozemeijer, F C Van Geer, Y Van Der Velde, M F P Bierkens, H P BroersAbstract:Enhanced knowledge of water and solute pathways in catchments would improve the understanding of dynamics in water quality and would support the selection of appropriate water pollution mitigation options. For this study, we physically separated Tile Drain effluent and groundwater discharge from an agricultural field before it entered a 43.5-m ditch transect. Through continuous discharge measurements and weekly water quality sampling, we directly quantified the flow route contributions to surface water discharge and solute loading. Our multi-scale experimental approach allowed us to relate these measurements to field-scale NO 3 concentration patterns in shallow groundwater and to continuous NO 3 records at the catchment outlet. Our results show that the Tile Drains contributed 90-92% of the annual NO 3 and heavy metal loads. Considering their crucial role in water and solute transport, enhanced monitoring and modeling of Tile Drainage are important for adequate water quality management. © 2010 Published by Elsevier Ltd. All rights reserved.
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Integrated modeling of groundwater–surface water interactions in a Tile‐Drained agricultural field: The importance of directly measured flow route contributions
Water Resources Research, 2010Co-Authors: Joachim Rozemeijer, F C Van Geer, Y Van Der Velde, R. G. Mclaren, Hans Peter Broers, Marc F. P. BierkensAbstract:Understanding the dynamics of groundwater-surface water interaction is needed to evaluate and simulate water and solute transport in catchments. However, direct measurements of the contributions of different flow routes from specific surfaces within a catchment toward the surface water are rarely available. For this study, we physically separated the Tile Drain discharge toward a 43.5 m ditch transect from the groundwater-plus-overland flow routes. Direct groundwater flow and ephemeral overland flow were jointly captured in three sheet pile in-stream reservoirs, while the effluent from three Tile Drain outlets was collected in vessels. Our flux measurements showed that, in response to a rainfall event, the Tile Drain contribution to the total ditch discharge decreased from 80% to 28%. We used these flow route measurements to calibrate a field-scale integrated water transport model. The HydroGeoSphere code was used because it simultaneously solves the flow regimes in the variably saturated domain, the Tile Drain domain, and the surface flow domain. This simultaneous solution is needed for a correct representation of the mutual interactions between groundwater flow, Tile Drain flow, and ditch water flow. Our model produced a flow distribution between the flow paths which deviated only 2% from the measured flow distribution. A sensitivity analysis showed that model parameters related to Tile Drain entrance resistance and to the resistance to water flow through the surface water system controlled the water flow route distribution but with little effect on groundwater levels. This indicates that a model calibration based on groundwater levels alone does not necessarily produce a correct representation of the flow route contributions. © 2010 by the American Geophysical Union.