Spatial distribution of water level impacting back-barrier bays

Aretxabaleta, Alfredo L.; Ganju, Neil K.; Defne, Zafer; Signell, Richard P.

doi:https://doi.org/10.5194/nhess-19-1823-2019

Articles | Volume 19, issue 8

https://doi.org/10.5194/nhess-19-1823-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/nhess-19-1823-2019

© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 19, issue 8

Research article

|

20 Aug 2019

Research article |

| 20 Aug 2019

Spatial distribution of water level impacting back-barrier bays

Alfredo L. Aretxabaleta, Neil K. Ganju, Zafer Defne, and Richard P. Signell

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Final revised paper (published on 20 Aug 2019)
Preprint (discussion started on 04 Dec 2018)

Interactive discussion

Status: closed

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

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- Supplement

RC1: 'Review of "Spatial distribution of water level impact to back-barrier bays" by Aretxabaleta et al (manuscript # nhess-2018-320)', Anonymous Referee #1, 03 Jan 2019
- AC1: 'Response to Anonymous Referee #1', Alfredo Aretxabaleta, 08 Apr 2019
RC2: 'review', Anonymous Referee #2, 07 Feb 2019
- AC2: 'Response to Anonymous Referee #2', Alfredo Aretxabaleta, 08 Apr 2019

Peer-review completion

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

ED: Reconsider after major revisions (further review by editor and referees) (20 Apr 2019) by Ira Didenkulova

AR by Alfredo Aretxabaleta on behalf of the Authors (01 Jun 2019) Author's response Manuscript

ED: Referee Nomination & Report Request started (03 Jun 2019) by Ira Didenkulova

RR by Anonymous Referee #1 (18 Jun 2019)

RR by Anonymous Referee #3 (12 Jul 2019)

Suggestions for revision or reasons for rejection

Review of “ Spatial distribution of water level impact to back-barrier bays “ by Alfredo L. Aretxabaleta et. al.

The manuscript is addressed to a very relevant issue concerning the construction of a simple and fast running model aimed to provide sufficient accurate calculation of ensuing response (transfer) of the water level in a semi-enclosed bays, forced by offshore sea level fluctuations and local friction stress by winds acting on the surface of water body, modulated by bay geometry and bathymetry.
The authors propose a transfer estimates of offshore to bay water level using a combination of observations, analytical models based on appropriate simplifications of the bay system, and numerical simulations that provide, as underlined by the authors, the needed spatial distribution and more realistic frictional control.
The topic is interesting, methodology and results appear convincing and well documented.
Therefore, I think that the manuscript is worth to be accepted for publication in NHess.
However , on a first reading, I found some difficulties for a sufficiently fast comprehension of some issues that instead appear, on a second reading, to be fundamental in the structure of the paper, in particular the issue related to the question how the remote forcing factors due to offshore water level modulations and local ones due to wind might be combined to provide a reliable, sufficiently accurate, representation of the water level trends within the bay.
I think this is one of the most relevant aspect of the proposal , that I suggest to the authors to revise accurately, before the final submission of the manuscript.
In the manuscript the issue is discussed, in rather simplified way, in paragraph 4.2. and 4.3 which refer to a very interesting paper of Wong and Moses-Hall (1998). These latter authors, on a base of a simple conceptual model with a very highly simplified bathymetry and geometry, derive the basic idea that the observed subtidal fluctuation in current and sea level within an estuary can be divided into two parts, linearly related, one forced by the local wind induced effect, and the other forced by the remote effect due to offshore sea level fluctuation.
Wong and Moses-Hall also observe that such uncoupling between the level modulations in the bay due to the two forcing factors, may not be readily transferable to a realistic estuary with complex bathimetry and geometry. In the latter case, wind driven flows might have a very complex structure with presence of a strong three-dimensional features characterized by a combination of vertical and horizontal recirculation flows. (In order to explore this aspect, the authors might refer to the following papers: HUNTER, J.R. and HEARN, C.J. (1987). "Lateral and Vertical Variation in Wind-Driven Circulation in Long, Shallow Lakes". J. Geophys. Res. 92, 13106-13114; Cioffi, Francesco, Francesco Gallerano, and Enrico Napoli. "Three-dimensional numerical simulation of wind-driven flows in closed channels and basins." Journal of Hydraulic Research 43.3 (2005): 290-301).
The dominance of horizontal or vertical recirculation flows depends mainly on the bay bathimetry, geometry and on the forcing factor characteristics ( winds, tides, storm surge, etc…), amplitude and frequency. Depending on such characteristics the dynamics of the hydraulic systems might be linear, weakly, as well as, fully nonlinear with eventually possibility of resonance phenomena,
In the manuscript, the authors apply the proposed methodology, to a very complex water body with multiple mouths connecting the bay to the sea; in fact, their correctly use 3D simulations to identify the spatial distribution of the transfer response of the bay, and provide a very convincing criteria to correct the outputs of analytical model.
But, in the case of the simultaneal presence of wind and offshore level modulations the weakly nonlinearity of the system, in the specific case examined, should be demonstrated in such a way.
The authors in the session in which results are discussed, try to demonstrate the correctness of this assumption in the specific case examined, but in my opinion not in a enough rigorous way. A reasonable effort to prove the validity of the assumption surely will increase the worth of the paper and its impact.
Just as a suggestion, I believe that the hypothesis of weakly nonlinearity ( derived by Wong and Moses-Hall ) in the specific case study examined, probably ( but this deserves a more detailed analysis) holds because the frequencies of the remote and local forcing factors are sufficient different. In particular, I suggest to the authors to revise paragraphs 4.2 and 4.3, and the related issues faced in the result discussion sessions.

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ED: Publish subject to minor revisions (review by editor) (12 Jul 2019) by Ira Didenkulova

AR by Alfredo Aretxabaleta on behalf of the Authors (24 Jul 2019) Author's response Manuscript

ED: Publish subject to minor revisions (review by editor) (25 Jul 2019) by Ira Didenkulova

Dear Dr. Aretxabaleta et al,

I thank you for your new revised paper! It is much improved now. I should say, that there was one more late review on your paper, which came after I made my "minor revision" decision. It also requires minor revision and I kindly ask you to take these comments into account. Please, see the list below.
As before I kindly ask you to submit your response to these comments and include, in the same author reply document, a track changes document between the old manuscript and the new one.

SUGGESTIONS FOR REVISION
The paper is much improved, and in good condition for publication. A few suggestions for minor edits are included below.

DETAILED INPUTS
All the paper’s paragraphs have no spacing between them- I hope this isn’t the way a final publication will look!

Section 4.1: Consider adding text that explains why you define K (presumably to reduce the equations?) and what it represents (if simple to explain).

Section 4.2: This section generally seems better now, but I highly recommend some simple clarifications associated with application of Eq. 12 – after it is presented, add text clarifying how it is applied with k being an imaginary number, for those who are not specialists in derivations and applications of wave equations (a good part of the likely readership of the paper). I understand the imaginary wavenumber leads to exponential decay. But does one take the real part of the solution? The magnitude? I applied it and plotted the magnitude, and it seems to give similar results to yours.

145 – If frequency is applied in radians, then "(angular)" frequency makes sense, but if frequency is applied in cycles (as I believe it is here), then I believe you should just use the term "cyclic frequency" or "frequency". So I think it's a bit confusing to say cyclic (angular) frequency. Choose what you feel is best, but give this some more thought.

line 160- should this have an equation number?

Section 5.1
page 8 - this appears to be one long block of text (though difficult to tell due to no paragraph spacings) .... consider breaking up separate topics into topical paragraphs- eg the effects of the breach

fig 7b- might explicitly state in the caption that x/L = 1 is north end of bay – just to ease interpretation

line 323- “under developed” isn’t a word pair?

I thank you very much for your submission and look forward to seeing the revised version of your manuscript!

Sincerely,
Ira Didenkulova
NHESS editor

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AR by Alfredo Aretxabaleta on behalf of the Authors (25 Jul 2019) Author's response Manuscript

ED: Publish as is (30 Jul 2019) by Ira Didenkulova

AR by Alfredo Aretxabaleta on behalf of the Authors (30 Jul 2019) Manuscript

Short summary

Water levels in bays are affected by open-ocean changes and wind. Tides are more dampened in the bays than storm surges and sea level rise. We compare observed and modeled levels with ocean conditions and combine them with analytical models. We consider the local setup, caused by wind along the bay. Expansion using the ADCIRC tidal database will allow coverage of other bay systems on the United States East Coast. Spatial estimates of water level can inform decisions about bay flooding hazards.