Exploring river–aquifer interactions and hydrological system response using baseflow separation, impulse response modeling,  and time series analysis in three temperate lowland catchments

Lu, Min; Rogiers, Bart; Beerten, Koen; Gedeon, Matej; Huysmans, Marijke

doi:https://doi.org/10.5194/hess-26-3629-2022

Articles | Volume 26, issue 13

https://doi.org/10.5194/hess-26-3629-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/hess-26-3629-2022

© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 26, issue 13

Research article

|

13 Jul 2022

Research article |

| 13 Jul 2022

Exploring river–aquifer interactions and hydrological system response using baseflow separation, impulse response modeling, and time series analysis in three temperate lowland catchments

Min Lu, Bart Rogiers, Koen Beerten, Matej Gedeon, and Marijke Huysmans

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Final revised paper (published on 13 Jul 2022)
Preprint (discussion started on 07 Sep 2021)

Interactive discussion

Status: closed

RC1:
'Comment on hess-2021-422', Anonymous Referee #1, 29 Sep 2021

The study looks in details at the hydrological interactions between lowland rivers and shallow quifers in three different catchments in Belgium. In their analysis, the authors use a combined approach of baseflow separation, impulse response modeling and time series analysis over a 30-year period. Overall, the paper is well-written and the results are insightful and very useful to the hydrology community. I think the paper should be published after addressing the following minor/technical comments:

- Looking at Fig. 11(c), I can see a slight overestimation of the groundwater levels prior to 2000. Can the impulse response parameters be tuned to improve the fit to the data? Also the seasons, as decribed in the text, are not clear on the figure. Consider zooming in.

- Section 4.2.2: I am interested to look at the entire eigenvalue spectrums. I understand that the first mode at the 3 different sites dominate the rest of the modes. Does the spectrum die after the first leading modes? I expect the leading modes to change if there is some sort of an extreme rainfall event. It might be helpful to comment and discuss this further in the text.

- Do you expect the BFI estimates in these groundwater-dominated lowland catchments to change if the precipitation regimes change?

- The figures could be annotated better. For instance, in Fig. 13 does not label the black and the gray curves.

Citation: https://doi.org/10.5194/hess-2021-422-RC1
- AC1: 'Reply on RC1', Min Lu, 23 Oct 2021
  
  Dear Anonymous Referee #1,
  First of all, thank you very much for reviewing our paper. We are very grateful for your time and comments that help to improve the manuscript.
  We have responded point-by-point to your comments and suggestions. Please check the detailed replies in the supplement, with your original comments in italic and our answers in blue. A revised manuscript which specifies the adjustments based on your comments will be provided at a later stage, awaiting the review from a second referee and the editor’s decision.
  We are looking forward to your further assessment.
  On behalf of all authors,
  With best regards,
  Min Lu
  Corresponding author
  
  Citation: https://doi.org/10.5194/hess-2021-422-AC1
RC2:
'Comment on hess-2021-422', Frank Schwartz, 27 Oct 2021

The comment was uploaded in the form of a supplement: https://hess.copernicus.org/preprints/hess-2021-422/hess-2021-422-RC2-supplement.pdf

Citation: https://doi.org/10.5194/hess-2021-422-RC2
- AC2: 'Reply on RC2', Min Lu, 20 Nov 2021
  
  Dear Prof. Dr. Franklin Schwartz,
  Thank you very much for reviewing our paper entitled “Exploring river–aquifer interactions and hydrological system response using baseflow separation, impulse response modelling and time series analysis in three temperate lowland catchments (HESS-2021-422)”. We appreciate your time and comments which will help improving the manuscript.
  In the supplement you will find our detailed responses and explanations (in blue) to your comments and suggestions (in italic). A revised manuscript will be prepared later with tracked changes made to the original manuscript based on your and other’s comments, awaiting the decision from the editor.
  We are looking forward to your further assessment.
  
  On behalf of all authors,
  With best regards,
  Min Lu
  Corresponding author
  
  Citation: https://doi.org/10.5194/hess-2021-422-AC2

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

ED: Reconsider after major revisions (further review by editor and referees) (20 Nov 2021) by Nadia Ursino

AR by Min Lu on behalf of the Authors (30 Dec 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (06 Jan 2022) by Nadia Ursino

RR by Anonymous Referee #3 (16 Feb 2022)

Suggestions for revision or reasons for rejection

This manuscript describes a study on three watersheds in low-lying areas of Belgium. The key interest is to describe how groundwater levels respond to weather (precipitation and temperature—a stand-in for evaporation rate), and seasonality, and then how groundwater influences or contributes to streamflow.

Various techniques are used to separate baseflow from runoff, and impulse-response models are used to model the links from precipitation to groundwater levels to baseflow. The impulse-response methods used have separate terms for slow and fast responses. In addition, time-series analysis is used to determine long-term trends and seasonality in key variables.

I found the methods used and the analysis to be interesting and worthwhile. However, the manuscript seems to be ambivalent about its purpose. That is, are the authors interested in these three watersheds, or in all similar watersheds? Are they looking for the techniques that work for these watersheds, or are they providing a specific example that can be followed for other watersheds? My impression is that it is a combination—specific techniques applied to characterize specific watersheds that can be used to characterize other watersheds as well. If this last combination is the intention of the authors, it would be helpful if they would make it more apparent.

The basic structure of the project—comparing results from baseflow separation to results from the impulse-response modeling—was a clever combination of empirical and modeling approaches that yielded important characteristics of the watersheds.

Specific comments
Line 73—two watershed areas are given but there are three watersheds.
Figure 11—Perhaps an intuitive explanation for the principal component time series?

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RR by Anonymous Referee #4 (27 May 2022)

ED: Publish subject to minor revisions (review by editor) (27 May 2022) by Nadia Ursino

AR by Min Lu on behalf of the Authors (09 Jun 2022) Author's response Author's tracked changes Manuscript

ED: Publish as is (10 Jun 2022) by Nadia Ursino

AR by Min Lu on behalf of the Authors (14 Jun 2022)

Short summary

Lowland rivers and shallow aquifers are closely coupled. We study their interactions here using a combination of impulse response modeling and hydrological data analysis. The results show that the lowland catchments are groundwater dominated and that the hydrological system from precipitation impulse to groundwater inflow response is a very fast response regime. This study also provides an alternative method to estimate groundwater inflow to rivers from the perspective of groundwater level.