title: 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.
abstract: 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.
authors.affiliation: Department of Physical Geography, Utrecht University, P.O. Box 80115, NL-3508 TC Utrecht, The Netherlands; Deltares, P.O. Box 85467, NL-3508 TA Utrecht, The Netherlands. joachim.rozemeijer@deltares.nl
authors.forename: J C
authors.initials: JC
authors.lastname: Rozemeijer
authors.forename: Y
authors.initials: Y
authors.lastname: van der Velde
authors.forename: F C
authors.initials: FC
authors.lastname: van Geer
authors.forename: M F P
authors.initials: MF
authors.lastname: Bierkens
authors.forename: H P
authors.initials: HP
authors.lastname: Broers
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D019216:Metals, Heavy / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D014872:Water Movements; D014874:Water Pollutants, Chemical; D014876:Water Pollution; D014881:Water Supply
chemical_list: D019216:Metals, Heavy; D009566:Nitrates; D014874:Water Pollutants, Chemical