Groundwater flow and contaminant transport in the Selgi Watershed

The gap

Evidence profile

Sourced from the future work and stated research gap and future-work section of the source papers, classified as general, drawn from work published between 2024 and 2026, spanning 4 journals. Those papers have been cited 51 times in total.

Supporting evidence — 4 representative gaps

• Determination of critical nitrogen loss zones and high-resolution nitrate leaching modeling in drinking water protection areas with satellite-based algorithms (2026) · Precision Agriculture · doi

  This study demonstrates that nitrate leaching risk can show substantial spatial variability at sub-field scale. Uniform mitigation measures commonly applied in drinking water protec- tion areas may therefore not fully account for within-field differences in grain N uptake, N surplus, and nitrate leaching risk. By identifying spatial patterns of nitrate-prone zones, the presented framework provides a basis for more targeted mitigation strategies and site- specific groundwater protection approaches. The main contribution of this study is the inte- gration of satellite-derived, spatially explicit grain N uptake estimates with site-specific N balance calculations and soil–water–nitrate leaching modeling. The results of this study indicate that digital, science-based approaches can support a more spatially targeted strat- egy for nitrate mitigation under practical farming conditions and help prioritize mitiga- tion measures in areas with elevated risk. An additional input required for the N balance is information on N fertilization. In this study, these data were obtained directly from farmers. In future applications, integration into digital nutrient management systems may provide a practical pathway for broader implementation, as such systems already contain detailed information on N inputs (Donauer et al., 2025; Ostermaier-Welz et al., 2025). The long-term objective is the development of an automated workflow for large-scale nitrate risk assess- ment and the identification of nitrate-prone zones within drinking water catchments. Future work should extend the framework to multi-year analyses, crop rotations, and broader soil-climate regions in order to further improve robustness, transferability, and 1 3Precision Agriculture(2026)27:129Page 21 of 26 129 operational applicability. With these extensions, the approach has the potential to become a practical decision-support tool for targeted groundwater protection and site-specific agri- cultural management. Supplementary Information The online version contains supplementary material available at h t t p s : / / d o i . o r g / 1 0 . 1 0 0 7 / s 1 1 1 1 9 - 0 2 6 - 1 0 4 0 5 - x . Acknowledgements The authors acknowledge support from the project “digisens”, funded by the Bavarian State Ministry of Agriculture from 2020 to 2023; and the ongoing project “digiMan” (2024–2027), funded by the German Federal Ministry of Food and Agriculture (BMEL). Author contribution M.M. and K.-J.H. wrote the main manuscript text. J.D. conducted the nitrate leaching modeling. F.K. and F.L. developed and implemented the modeling approaches. J.S. and L.H. collected and generated the data. M.M. coordinated the study, integrated all components, and contributed across all aspects of the work. K.-J.H. supervised the project, acquired funding, and reviewed the manuscript. All authors reviewed and approved the final manuscript. Funding Open Access funding enabled and organized by Projekt DEAL. Bavarian State Ministry of Agricul- ture and German Federal Ministry of Food and Agriculture. Data availability The datasets generated and analysed during the current study are provided in the Appendix of this manuscript. Additional data supporting the findings of this study are available from the corresponding author on reasonable request. The data include site-specific modeling, deep drilling data, and satellite-based datasets used for modeling and analysis.

  generalfuture work
  Keywords: nitrate modeling leaching risk site specific agriculture ministry manuscript mitigation water targeted approaches support practical
• Analysis of hydrogeochemical processes regulating groundwater quality in a tropical agricultural landscape of northwestern Mexico (2026) · Environmental Earth Sciences · doi

  Future research should focus on continuous monitoring of the MRA to better capture seasonal and interannual variabil- ity in groundwater quality, particularly during dry and rainy periods, when salinization, nutrient leaching, and microbial contamination are most pronounced. This long-term moni- toring should be integrated with predictive hydrogeochemi- cal models to simulate salinity evolution under different irrigation intensification, recharge variability, and land-use change scenarios. In addition, isotopic tracing techniques (e.g., δ¹⁵N and δ¹⁸O) are recommended to more accurately distinguish between fertilizer-derived and wastewater-derived nitrate sources, improving the understanding of contaminant path- ways in agricultural and semi-urban zones. Climate change scenario analysis should also be incorporated to evaluate the potential impacts of reduced recharge and increased evapoconcentration on long-term groundwater quality and availability. From a management perspective, strengthening con- tinuous monitoring programs focused on salinity, sodium hazards, and nutrient loading is essential, particularly in agricultural areas where groundwater degradation is more severe. Sustainable irrigation practices, optimized fertilizer application, and protection of recharge zones are critical measures to reduce further salinization and chemical dete- rioration of the aquifer. Although the proposed approaches are focused on the MRA, they are also transferable to other intensively irri- gated semi-arid aquifers in northwestern Mexico, where similar hydroclimatic pressures and land-use intensification patterns are observed. Integrating hydrogeochemical, land-use, and climatic data within adaptive management frameworks can sup- port evidence-based decision-making for groundwater sustainability. Such interdisciplinary approaches are nec- essary to ensure the long-term protection and availability of groundwater resources in vulnerable tropical agricul- tural systems. Supplementary Information The online version contains supplementary material available at h t t p s : / / d o i . o r g / 1 0 . 1 0 0 7 / s 1 2 6 6 5 - 0 2 6 - 1 3 1 0 4 - y . Acknowledgements The lead author gratefully acknowledges the sup- port provided by SECIHTI through the Programa de Investigadoras e Investigadores por México (Project No. 7026). Author contributions YABT: Project administration, Investigation, Writing – original draft. OMA: Investigation, Formal analysis. JGL: Investigation, Writing –review & editing, Validation, Software. JGRP: Writing –review & editing. BRP: Visualization. JEM: Validation, Data curation. TAK: Writing –review & editing. MNRV: Validation. Funding No funding was received for this study. Data availability No datasets were generated or analysed during the current study.

  generalfuture work
  Keywords: groundwater writing long term recharge land availability investigation review editing validation monitoring quality particularly salinization
• Groundwater Flow and Contaminant Transport Modeling in the Selgi Watershed, Woleka Sub Basin, Ethiopia (2026) · Ethiopian Journal of Water Science and Technology · doi

  The study identifies a gap in the understanding of groundwater flow and contaminant transport in the Selgi Watershed. The study identifies a need for the development of models that can simulate nitrate concentration and groundwater levels.

  generalstated research gapevidence 5/5
  Keywords: study identifies gap understanding groundwater flow contaminant transport
• Effects of Rainfall Intensity and Slope on Infiltration Rate, Soil Losses, Runoff and Nitrogen Leaching from Different Nitrogen Sources with a Rainfall Simulator (2024) · Sustainability · cited 51× · doi

  Investigating the effects of other factors such as vegetation cover and farming practices, - Studying the impact of rainfall intensity and slope gradient on other soil processes, - Examining the effects of different nitrogen fertilizer sources on nitrogen leaching

  generalfuture-work sectionevidence 5/5
  Keywords: investigating effects other factors vegetation cover farming practices

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