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Title (Primary) Field-scale measurements for separation of catchment discharge into flow route contributions
Author van der Velde, Y.; Rozemeijer, J.C.; de Rooij, G.H.; van Geer, F.C.; Broers, H.P.;
Journal Vadose Zone Journal
Year 2010
Department BOPHY;
Volume 9
Issue 1
Language englisch;
Abstract Agricultural pollutants in catchments are transported toward the discharging stream through various flow routes such as tube drain flow, groundwater flow, interflow, and overland flow. Direct measurements of flow route contributions are difficult and often impossible. We developed a field-scale setup that can measure the contribution of the tube drain flow route to the total discharge toward the surface water system. We then embedded these field-scale measurements in a nested measurement setup to asses the value of field-scale measurements for interpretation of catchment-scale discharge and nitrate concentrations using a linear flow route mixing model. In a lowland catchment, we physically separated the tube drain effluent from the discharge of all other flow routes. Upscaling the field-scale flow route discharge contributions to the subcatchment and the catchment scale with a linear flow route mixing model gave a good prediction of the catchment discharge. Catchment-scale nitrate concentrations were simulated well for a heavy rainfall event but poorly for a small rainfall event. The nested measurement setup revealed that the fluxes at a single field site cannot be representative for the entire catchment at all times. However, the distinctly different hydrograph reaction of the individual flow routes on rainfall events at the field site made it possible to interpret the catchment-scale hydrograph and nitrate concentrations. This study showed that physical separation of flow route contributions at the field scale is feasible and essential for understanding catchment-scale discharge generation and solute transport processes. To reduce surface water pollution from agricultural sources quantification of processes that generate nutrient transport is necessary. We related field-scale flow route discharges to catchment-scale nitrate transport. The findings of this study stress the importance of a nested measurement setup when we want to evaluate pollution-reducing measures.
ID 10619
Persistent UFZ Identifier
van der Velde, Y., Rozemeijer, J.C., de Rooij, G.H., van Geer, F.C., Broers, H.P. (2010):
Field-scale measurements for separation of catchment discharge into flow route contributions
Vadose Zone J. 9 (1), 25 - 35