Abstract

The 'Dominant Source Layer' (DSL) is defined as the riparian zone (RZ) depth stratum that contributes the most to water and solute fluxes to streams. The concept can be used to explain timing and amount of matter transferred from RZs to streams in forest headwaters. Here, we investigated the potential impact of future climate changes on the long-term position of the DSL in a subhumid Mediterranean headwater catchment. We used the rainfall-runoff model PERSiST to simulate reference (1981-2000) and future (2081-2100) stream runoff. The latter were simulated using synthetic temperature, precipitation, and inter-event length scenarios in order to simulate possible effects of changes in temperature, rainfall amount, and rainfall event frequency and intensity. Simulated stream runoff was then used to estimate RZ groundwater tables and the proportion of lateral water flux at every depth in the riparian profile; and hence the DSL. Our simulations indicated that future changes in temperature and precipitation will have a similar impact on the long-term DSL position. Nearly all scenarios projected that, together with reductions in stream runoff and water exports, the DSL will move down in the future, by as much as ca. 30 cm. Shallow organic-rich layers in the RZ will only be hydrologically activated during sporadic, large rainfall episodes predicted for the most extreme inter-event length scenarios. Consequently, terrestrial organic matter inputs to streams will decrease, likely reducing catchment organic matter exports and stream dissolved organic carbon concentrations. This study highlights the importance of identifying vertical, hydrologically active layers in the RZ for a better understanding of the potential impact of future climate on lateral water transfer and their relationship with surface water quality and carbon cycling.

Keywords

Terrestrial-aquatic interface; Hydrological connectivity; Hydrological modelling; Catchment biogeochemistry; Mediterranean climate; Environmental change

Published in

Journal of Hydrology
2021, Volume: 595, article number: 126014
Publisher: ELSEVIER

SLU Authors

• Ledesma, Jose

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    
  • Centre for Advanced Studies of Blanes (CEAB-CSIC)
  • Karlsruhe Institute of Technology

• Ruiz-Pérez, Guiomar

  • Department of Crop Production Ecology, Swedish University of Agricultural Sciences
    

• Futter, Martyn

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Ensure availability and sustainable management of water and sanitation for all


UKÄ Subject classification

Oceanography, Hydrology, Water Resources


Publication identifier

DOI: https://doi.org/10.1016/j.jhydrol.2021.126014

Permanent link to this page (URI)

https://res.slu.se/id/publ/112076