Abstract
Flow regimes are increasingly impacted by more extreme natural hazards of droughts and floods as a result of climate change, compounded by anthropogenic influences in both urban and intensively managed rural catchments. However, the characteristics of sustainable flow regimes that are needed to maintain or restore hydrologic, biogeochemical and ecological functions under rapid global change remain unclear and contested. We conducted an intercomparison of two streams in the Berlin-Brandenburg region of northeast Germany, which are both mesoscale subcatchments of the Spree river: an intermittent rural agricultural stream (the Demnitzer Millcreek) and a heavily anthropogenically impacted urban stream (the Panke). Through tracer-based analyses using stable water isotopes, we identified the dominant physical processes (runoff sources, flowpaths and age characteristics) sustaining streamflow over multiple years (2018-2023), including three major drought years (2018- 2020, 2021-2022). In the urban stream, low flows are regulated through artificially increased baseflow from treated wastewater effluents (by up to 80 %), whilst storm drainage drives rapid, transient high-flow and runoff responses (up to 80 %) to intense convective summer rainfall. The intermittent groundwater-dominated rural stream experienced extended no-flow periods during drought years (_60% of the year) and only moderate storm runoff coefficients (<10 %) in winter along near-surface flow paths after heavy rainfall. In both streams, groundwater dominance with young water influence prevails, with low water ages in the urban stream (<10 %) despite significant urban runoff and higher ones in the rural stream (15 %). Urban cover resulted in a mean transit time of 4 years compared to arable land at _3 years, highlighting the interlinkages of land use and catchment properties on catchment transit times. Understanding seasonal and interannual variability in streamflow generation through a tracer-based hydrological template has the potential to assess the impacts of natural hazards on the sustainability of future baseflow management, including wider water quality and ecological implications across anthropogenically impacted environments..
| Original language | English |
|---|---|
| Pages (from-to) | 3907-3924 |
| Number of pages | 18 |
| Journal | Natural Hazards and Earth System Sciences |
| Volume | 24 |
| Issue number | 11 |
| Early online date | 14 Nov 2024 |
| DOIs | |
| Publication status | Published - 14 Nov 2024 |
Bibliographical note
Publisher Copyright: © Author(s) 2024.This article is part of the special issue “Current and future water-related risks in the Berlin–Brandenburg region”. It is not associated with a conference.
Acknowledgements: We acknowledge David Dubbert and Franziska Schmidt from the IGB Isotope Lab for help with the isotope analysis, Jonas Freymüller for help with site installations and maintenance of equipment in the DMC, and Jan Christopher for help with sampling.
Data Availability Statement
The data used in this study are available on the Leibniz Freshwater and Environmental Database (FRED). The metadata for this study are available on https://doi.org/10.18728/igb-fred-865.0 (Warter, 2024). Data will be made available upon request. Public discharge data for the Panke river are available from the Berlin Senate at https://wasserportal.berlin.de/start.php (SenUVK, 2023). Climate data are available publicly from the German Weather Service (https://opendata.dwd.de/climate_environment/CDC/, DWD, 2023).The supplement related to this article is available online at: https://doi.org/10.5194/nhess-24-3907-2024-supplement.
Access to Document
- Warter_etal_NHESS_Impact_Of_Drought_VoR
This work is distributed under the Creative Commons Attribution 4.0 License. https://creativecommons.org/licenses/by/4.0/