Heinz et al. (2025) From Soil to Stream: Modeling the Catchment-Scale Hydrological Effects of Increased Soil Organic Carbon

Identification

• Journal: Open Access CRIS of the University of Bern
• Year: 2025
• Date: 2025-11-21
• Authors: Malve Heinz, Annelie Holzkämper, Rohini Kumar, Sélène Ledain, Pascal Horton, Bettina Schaefli
• DOI: 10.48620/96363

Research Groups

• Institute of Geography, University of Bern
• Oeschger Centre for Climate Change Research (OCCR)
• Agroscope

Short Summary

This study modeled the catchment-scale hydrological effects of increased soil organic carbon (SOC) in an agriculturally dominated catchment in Switzerland, finding that while SOC enhancement benefits soil water content and attenuates peak flows, it may also reduce groundwater recharge and downstream water availability.

Objective

• To investigate how increasing soil organic carbon (SOC) affects catchment-scale hydrology, including hydrological extremes.

Study Configuration

• Spatial Scale: Medium-sized, agriculturally dominated Broye catchment in Western Switzerland. Analyses were conducted at both plot and catchment scales.
• Temporal Scale: Not explicitly stated for the simulation period. The study investigates long-term hydrological effects and adaptation strategies.

Methodology and Data

• Models used: Mesoscale hydrologic modeling (mHM) framework.
• Data sources: Soil hydraulic parameters (bulk density, permanent wilting point water content, field capacity water content, saturated water content, saturated hydraulic conductivity) were adjusted based on literature-reported effects of SOC increases. Five SOC increase scenarios of varying depth and magnitude were evaluated.

Main Results

• At the plot scale, increased SOC led to higher net soil water content (2.99–8.13 %) and slightly higher evapotranspiration (0.15–0.4 %), while subsurface runoff was reduced (0.28–0.72 %).
• Increased water retention resulted in more soil water being retained and evaporated, leading to less water available for groundwater recharge and streamflow.
• At the catchment scale, streamflows were slightly reduced, and peak flows were modestly attenuated.
• Low flow responses varied by subcatchment characteristics and timing: increased frequency in warmer and drier subcatchments in some years, but reduced frequency in cooler and wetter subcatchments during spring and early summer.
• Overall, large-scale SOC increase, while beneficial for agricultural productivity and peak flow attenuation, may induce trade-offs by potentially reducing groundwater recharge and downstream water availability.

Contributions

• Quantifies the hydrological effects of increased SOC at both plot and catchment scales using a mesoscale hydrological model.
• Highlights potential trade-offs of large-scale SOC enhancement, specifically concerning groundwater recharge and downstream water availability, alongside benefits for agricultural productivity and peak flow attenuation.
• Provides insights into climate change adaptation strategies through agricultural management in a Swiss context.

Funding

• No specific funding projects, programs, or reference codes were mentioned in the provided text.

Citation

@article{Heinz2025From,
  author = {Heinz, Malve and Holzkämper, Annelie and Kumar, Rohini and Ledain, Sélène and Horton, Pascal and Schaefli, Bettina},
  title = {From Soil to Stream: Modeling the Catchment-Scale Hydrological Effects of Increased Soil Organic Carbon},
  journal = {Open Access CRIS of the University of Bern},
  year = {2025},
  doi = {10.48620/96363},
  url = {https://doi.org/10.48620/96363}
}