Abstract
Increased urbanization, coupled with the projected impacts of climatic change, mandates further evaluation of the impact of urban development on water flow paths to guide sustainable land-use planning. Though the general urbanization impacts of increased storm runoff peaks and reduced baseflows are well known; how the complex, non-stationary interaction of the dominant water fluxes within dynamic urban water stores sustain streamflow regimes over longer periods of time is less well quantified. In particular, there is a challenge in how hydrological modelling should integrate the juxtaposition of rapid and slower flow pathways of the urban ‘karst’ landscape and different approaches need evaluation. In this context, we utilized hydrological and water stable isotope datasets within a modelling framework that combined the commonly used Hydrologic Engineering Center Hydrological Modelling System (HEC-HMS) urban runoff model along with a simple hydrological tracer module and transit time modelling to evaluate the spatial and temporal variation of water flow paths and ages within a heavily urbanized 217 km2 catchment in Berlin, Germany. Deeper groundwater was the primary flow component in the upper reaches of the catchment within fewer urbanized regions, while the addition of wastewater effluent in the mid-reaches of the catchment was the dominant water supply to sustain baseflow in the lower main stem stream, with additional direct storm runoff and shallow subsurface contributions in the more urbanized lower reaches. Water ages from each modelling approach mirrored flow contributions and water age mixing potential in subsurface storage; with older average water and lower young water contributions in less urbanized sub-catchments and younger average water and higher young water contributions in more urbanized regions. The results from the first step towards more integrated tracer-aided hydrologic modelling tools for similar peri-urban catchments, given the potential limitations of simpler model frameworks. The results have broader implications for assessing the uncertainty in evaluating urban impacts on hydrological function under environmental change.
| Original language | English |
|---|---|
| Article number | e14814 |
| Number of pages | 17 |
| Journal | Hydrological Processes |
| Volume | 37 |
| Issue number | 2 |
| Early online date | 2 Feb 2023 |
| DOIs | |
| Publication status | Published - 16 Feb 2023 |
Bibliographical note
Funding Information:We acknowledge the BMBF (funding code 033W034A) which supported the stable isotope laboratory at IGB. Funding for DT was also received through the Einstein Research Unit ‘Climate and Water under Change’ from the Einstein Foundation Berlin and Berlin University Alliance. We acknowledge funding from the graduate School Urban Water financed by Interfaces Deutsche Forschungsgemeinschaft, Grant/Award Number: (GRK2032/2). CS is also funded by the ISOLAND Project of the Leverhulme Trust, Grant Number: (RPG‐2018‐425). CM and CS are funded for the project MOSAIC by the Einstein Stiftung Berlin, Grant/Award Number: EVF‐2018‐425. The authors would like to thank the two anonymous reviewers and editor (Jim McNamara) for the comments and feedback which has improved the manuscript. Open Access funding enabled and organized by Projekt DEAL.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.Keywords
- hydrological modelling
- urban hydrology
- water ages
- water stable isotopes
Access to Document
- Smith_etal_HP_Enhancing_Urban_Runoff_VOR
© 2023 The Authors. Hydrological Processes published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.