Shift of annual water balance in the Budyko space for catchments with
groundwater-dependent evapotranspiration

Wang, Xu-Sheng; Zhou, Yangxiao

doi:https://doi.org/10.5194/hess-20-3673-2016

Articles | Volume 20, issue 9

https://doi.org/10.5194/hess-20-3673-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/hess-20-3673-2016

© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 20, issue 9

Research article

|

08 Sep 2016

Research article |

| 08 Sep 2016

Shift of annual water balance in the Budyko space for catchments with groundwater-dependent evapotranspiration

Xu-Sheng Wang and Yangxiao Zhou

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Final revised paper (published on 08 Sep 2016)
Preprint (discussion started on 04 Nov 2015)

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC C5377: 'Comment on Wang and Zhou's discussion paper "Shift of annual water balance in the Budyko space for a catchment with groundwater dependent evapotranspiration"', Randall Donohue, 04 Dec 2015
- AC C5827: 'Reply to Reviewer#1', Xu-Sheng Wang, 26 Dec 2015
  - RC C5889: 'A few additional thoughts for Wang and Zhou', Randall Donohue, 04 Jan 2016
    - AC C5992: 'Additional reply', Xu-Sheng Wang, 06 Jan 2016
RC C5666: 'Review Fernando Jaramillo - "Shift of annual water balance in the Budyko space for a catchment with groundwater dependent evapotranspiration"', Fernando Jaramillo, 17 Dec 2015
- AC C5837: 'Reply reviewer #2', Xu-Sheng Wang, 27 Dec 2015
RC C5725: 'Comment on "Shift of annual water balance in the Budyko space for a catchment with groundwater dependent evapotranspiration"', Anonymous Referee #3, 21 Dec 2015
- AC C5843: 'Reply Reviewer #3', Xu-Sheng Wang, 27 Dec 2015

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Reconsider after major revisions (16 Jan 2016) by Roger Moussa

AR by Xu-Sheng Wang on behalf of the Authors (16 Feb 2016) Author's response

ED: Referee Nomination & Report Request started (22 Feb 2016) by Roger Moussa

RR by Fernando Jaramillo (14 Mar 2016)

Suggestions for revision or reasons for rejection

I must say that after the revision this manuscript has been considerably improved. The methodology is now understandable and can be replicated. The analysis of results is also extensive and informative. I also thank the authors for taking into account all my suggestions.

I have only the following minor additional comments,

• There is a problem with spaces between words along the manuscript. Many of the words don’t have a space in between. Please correct this along the text.
• Line 14 and 15- You could also say that for large basins, the effect of groundwater flow coming in and out of the basin ΔG may be negligible, since your basin is large than 1000 km2; Budyko (1958, 1974). But of course, that you will determine if this is the case due to the existence of shallow groundwater evapotranspiration.
• In Zone 1- Why does R or kV have no contribution to runoff Q? Why is all water in Zone 1 only going to groundwater or evapotranspiration? Please explain.
• Page 15 line 2- “finally the value of Gm is substituting into Eq. (9)”. Eq. 9 is not in terms of Gm, so I think the Equation number is wrong. Please correct.
• Lines 25-28 of page 13. Question: Is alpha also one of the outputs of the model for the “natural” conditions?
• Line 7 of Page 14 – How significant and what test was used; p<0.05?
• Line 20 Page 15 - I wouldn't say that it cannot be applied. Just that change in water storage within the basin may be considerable if analyzed at one-year the annual scale. As I said in the first review, the annual scale is sometimes not enough to guarantee steady state conditions. This is why it is not surprising that some years are in a condition of F>1. Now, if you take the mean of all the years, which in this case would imply adding the Q of the 55-years and dividing by 55, you would generate approximately steady-state conditions since water storage change can be negligible at larger time scales and in large basins. In this case, the mean values of the basin would fall close or even below the F=1 line. Try it!
• Figure 10 - If I understood correctly, the labels of each of the three bar groups Δ(Eld/P) in Figure 10 should be called 1) (Eld/P)1968-1987 -(Eld/P)1957-1967, 2) (Eld/P)1988-1997 -(Eld/P)1957-1967 and 3) (Eld/P)1998-2010 -(Eld/P)1957-1967 . Is this so? Same applies for Δ(CVQ /CVP). Please clarify. This error implies that some of the periods mentioned in the text are also wrong. Please see attached file for my corrections.

I also attach a file with some minor grammatical issues.

Referee Report: PDF

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RR by Anonymous Referee #4 (20 Mar 2016)

ED: Reconsider after major revisions (06 Apr 2016) by Roger Moussa

AR by Xu-Sheng Wang on behalf of the Authors (08 May 2016) Author's response Manuscript

ED: Referee Nomination & Report Request started (26 May 2016) by Roger Moussa

RR by Anonymous Referee #5 (01 Jul 2016)

Suggestions for revision or reasons for rejection

Overall, this manuscript examines the role of groundwater-dependent evaporation on the annual Budyko relationship between E/P and E0/P. By including groundwater as a source of evaporation in a catchment, water supply for evaporation is increased above P, rendering Budyko’s formulation at the annual scale inappropriate. As such, the abcd model is extended to include groundwater evaporation, and the resultant fluxes examined in terms of Budyko’s formulation.

The methodology is sound and the results and the discussion are of interest. However, the manuscript is a little difficult to follow. Some specific comments/queries I have follow:

P 7. And fig 2b: Labels on the y-axis indicating time frame (monthly?) of these measurements – particularly runoff should be included

8.4: Fig 2b seems to indicate that streamflow is pretty constant from year to year!

9.10: Personal opinion: “abnormal trend” is probably not the correct phrase for this. It is only “abnormal” because annual water balance in the catchments doesn’t suit Budyko’s original hypotheses (which are that the points are based on long-term average with no storage changes, also Budyko’s original figure was variability between catchments rather than year-to-year variability within a catchment). Also “trend” implies (to me) a progression through time, whereas the figures have dryness index on the x-axis.

11.26-28: It would be good to have an example catchment (C1?) with the groundwater contour lines plotted to help in understanding and visualising the zone-1/zone-2 boundary in your catchments.

12.9: So E1m depends on W only and not V?

Fig 4b: I may be wrong but the downward flow into the intermediate vadose zone in the diagram should be cR not R.

Fig 4b: Is there infiltration into zone-2 areas in the diagram? A labelled (I assume cP) flux arrow would help here.

Fig 4b again: The way it is drawn looks like zone 2 represents evaporation from deep groundwater, whereas from your description, zone 2 is where the water table is very close to the surface. In this case, your diagram would be better drawn with a sloping ground surface with zone 2 at the valley bottom, i.e. something similar to http://www.cgenarchive.org/uploads/2/5/2/6/25269392/2902862_orig.gif. A more accurate diagram would help with conceptual understanding of the abcd-ge model.

15.23-24: How can all the catchments have the same RMSE?

16.23: It’s worth mentioning here that changes in climate characteristics (e.g. seasonal rainfall or extreme rainfall events) over the second time period could also lead to Qnat being different from Qobs (i.e. it’s not necessarily all due to irrigation or groundwater)

Figure 6: It would be better to have the same x-axis tick mark spacing on the four panels. For panel d, the legend should read “Actual ET” not “Actrual ET”. Also, (and this applies to figure 3 as well) it would be better when presenting data for a particular catchment to have the catchment number (C1-C6) on the panel rather than a), b) etc. – similar to figure 7 and 10.

Figure 7: It would be good to have “F” on the figure itself, as you refer to “F” when talking about the figure but it’s not there (of course E/P is though…)

17.16: Should be C4 and C6 here – also there still related to aridity index, but less so (“less sensitive”?)

I am confused by Figure 8. Firstly (and this occurs throughout the paper), the HRC is defined on p5.14 as the Hailiutu River catchment, which is also denoted C1. Is this correct – i.e. is C1 identical to the HRC? If so, it is confusing to interchange these two throughout the manuscript. Secondly, none of the catchments C1-C6 have E/P greater than about 2, whereas Figure 8a (HRC?) has E2/P close to 4 for very dry years. How can I reconcile the two figures?

Figure 9: spelling mistake in the legend: “Cachments data”

20.17-18: What about groundwater from originating in other catchments (lateral flow) or inter-basin transfers?

21.17-19: And also that your modelled change in storage may not be representative of actual change in storage for many different reasons (misspecified model, data uncertainty, problems with parameter calibration and so on…)

I find section 5.3 quite difficult to follow – and the aim of this section is not really clear to me. It is not obvious what “Landscape-driven change” is, and why it’s important. If this section is needed, a better description of what you’re trying to achieve here would be good.

23.1: CVq looks like coefficient of variability rather than variability (variance). Is it?

General comments about the figures: There are a few spelling mistakes in the figures as noted above. Spending some time to get the figures more consistent would make the paper much better, e.g. you have “aridity index”, “phi” and “E0/P” in different figures and these are all the same thing. Similarly the “F” and “E/P” issue discussed above. (See also comments above about the panel labelling.)

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RR by Anonymous Referee #3 (04 Jul 2016)

Suggestions for revision or reasons for rejection

Review of “Shift of annual water balance in the Budyko space for a catchments with groundwater dependent evapotranspiration”

I understand that this is the second revision of the manuscript and that the authors did substantial effort to address the comments of the previous reviewers. I especially like that the authors incorporated 5 additional catchments and now use Fu's equation.

However, it seems like there was a clear misconception between the authors and the reviewers, as the reviewers argued the authors present a (not novel) way to incorporate storage effects into the Budyko framework. The authors, however, wanted to point out in particular the effect of groundwater-dependent evapotranspiration. I still don't think that this kind of misconception is resolved within the present version of the manuscript. Please add a better and more concise motivation to your introduction (and abstract), that clearly points out the novelty of your approach and how this goes beyond previous studies (Istanbulluoglu, etc.). This could be done for example somewhere on page 4.

I don't have too many specific comments as the manuscript was already going through multiple revisions:

P. 3, L. 11ff: For the discussion on interannual variability please check also: "Koster, R.D., and Suarez, M.J. (1999). A Simple Framework for Examining the Interannual Variability of Land Surface Moisture Fluxes. Journal of Climate 12, 1911–1917." and
"Gentine, P., D’Odorico, P., Lintner, B.R., Sivandran, G., and Salvucci, G. (2012). Interdependence of climate, soil, and vegetation as constrained by the Budyko curve. Geophysical Research Letters 39"

P. 3, L. 29: What do you mean by “extremely arid situations”? I think the term “arid” is more used to describe climatic conditions and not events such as droughts. Better use simply “dry”.

P. 4, L. 22ff: In the overview of what is done in the study it will help a lot if you refer to the respective sections.

P.6, L. 4: From Figure 1 it seems like all six catchments are located in the part of the Erdos Plateau with highest mean annual rainfall. Does this play a role for the overall interpretation of the results.

P.9, L. 10ff: You might point out again (in one or two sentences) what you will do different than Istanbulluoglu.

P. 15, L30: You can leave out “not very high”, I guess. Sounds a bit sloppy.

P. 21, L27-30: Please also check "Greve, P., Gudmundsson, L., Orlowsky, B., and Seneviratne, S.I. (2016). A two-parameter Budyko function to represent conditions under which evapotranspiration exceeds precipitation. Hydrol. Earth Syst. Sci. 20, 2195–2205." in this context.

P. 23, L. 26ff: I pretty much like the limitation remark. However, I think some (more general) shortcomings of your approach should be also mentioned here. These are especially related to the data you use. I especially miss a discussion on potential biases stemming from E0-estimates (since there are so many different ways to handle and estimate E0). Also biases in P could alter your results.

Before having some specific comments on the figures, I just want to point out that the quality of the figures has substantially improved.

Figure 3: Please note in the caption that the x-axes are different between (a) and the other subfigures. And what does the grey form indicate in subplot (a)? Is it necessary?

Figure 5: The labeling of the y-axes actually does not correspond to the explanation in the caption.

General comment:

Please revise the English usage and grammar throughout the manuscript. If possible by a native speaker.

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ED: Publish subject to minor revisions (Editor review) (19 Jul 2016) by Roger Moussa

AR by Xu-Sheng Wang on behalf of the Authors (28 Jul 2016) Author's response Manuscript

ED: Publish as is (02 Aug 2016) by Roger Moussa

AR by Xu-Sheng Wang on behalf of the Authors (04 Aug 2016)

Short summary

This study reveals the effects of groundwater-dependent evapotranspiration (GDE) in the shift of annual water balance for a catchment in the Budyko space. The ABCD model is modified to incorporate GDE in simulating the monthly hydrological behaviors of a catchment, and the results are aggregated to annual data. GDE enhances the occurrence of excess evapotranspiration (E / P > 1) in dry years, which could not be captured by the traditional Budyko curves. Six catchments are analyzed with the model.