Numerical groundwater flow and nitrate transport assessment in alluvial aquifer of Varaždin region, NW Croatia

Scientific paper - Original scientific paper

• Author: Igor Karlović
• Author: Kristijan Posavec
• Author: Ozren Larva
• Author: Tamara Marković
• Author's institution: Croatian Geological Survey
• Author's institution: University of Zagreb; Faculty of Mining, Geology and Petroleum Engineering; (Department of Geology and Geological Engineering)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geology
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mining, Petroleum and Geology Engineering

Abstract (english)

Study region: The Varaždin alluvial aquifer located in the Drava River valley. Study focus: The study area is characterized by agricultural activity, which raised concerns due to the high nitrate concentration in groundwater. The present study aims to evaluate future nitrate concentrations in groundwater using the numerical groundwater flow and transport modeling. The regional model was generated in GMS software, using the MODFLOW code for steady-state groundwater flow model, and MT3DMS code for nitrate transport model. Advective-dispersive transport was simulated, without a chemical retardation process. The calibrated model was used to investigate the evolution of groundwater nitrate concentrations for the next 20 years under four scenarios: a) current nitrate input; b) zero input from wastewater; c) agricultural input reduced by 50%; d) input from natural vegetation and surface water New hydrological insights for the region: The scenario analysis demonstrated that reducing the nitrate input from agricultural areas yields a considerable reduction of nitrate in groundwater, while the impact of wastewater is negligible. Neither of the scenarios reached concentrations below threshold value of 50 mg/L for the entire aquifer in the next 20 years. The nitrate concentration in the northern part of the aquifer will remain low, mainly due to the dilution from river. The central part of the aquifer is highly dependent on changing the on-ground nitrate concentration, showing inertia regarding the nitrate attenuation in groundwater.

• Keywords (english): numerical modeling; nitrate; transport; water budget; Varaždin alluvial aquifer
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Journal of Hydrology: Regional Studies
• Numbering: vol. 41, 101084
• p-ISSN: 2214-5818
• DOI: https://doi.org/10.1016/j.ejrh.2022.101084
• URN:NBN: urn:nbn:hr:169:414859
• Publication: 2022-06
• Project: Number: IP-2016-06-5365; Title (croatian): Podrijetlo, ponašanje i modeliranje transporta nitrata u varaždinskom aluvijalnom vodonosniku; Acronym: TRANITAL; Leader: Tamara Marković; Jurisdiction: Croatia; Funding stream: IP
• Document URL: https://linkinghub.elsevier.com/retrieve/pii/S2214581822000970
• Type of resource: Text
• Access conditions: Open access
• Created on: 2023-01-25 15:05:26