Impact of the Hoa Binh dam (Vietnam) on water and sediment budgets in the Red River basin and delta

Vinh, V. D.; Ouillon, S.; Thanh, T. D.; Chu, L. V.

doi:https://doi.org/10.5194/hess-18-3987-2014

Articles | Volume 18, issue 10

https://doi.org/10.5194/hess-18-3987-2014

© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

https://doi.org/10.5194/hess-18-3987-2014

© Author(s) 2014. This work is distributed under
the Creative Commons Attribution 3.0 License.

Articles | Volume 18, issue 10

Research article

|

10 Oct 2014

Research article |

| 10 Oct 2014

Impact of the Hoa Binh dam (Vietnam) on water and sediment budgets in the Red River basin and delta

V. D. Vinh, S. Ouillon, T. D. Thanh, and L. V. Chu

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Final revised paper (published on 10 Oct 2014)
Preprint (discussion started on 10 Jan 2014)

Interactive discussion

Status: closed

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

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RC C347: 'Important research, the model does not answer the questions posed.', John Shaw, 10 Mar 2014
- AC C890: 'Author Comment: Reply to the comment by J. Shaw, referee', Sylvain OUILLON, 11 Apr 2014
RC C418: 'Supporting evidence requires proper presentation', Maximiliano Sassi, 12 Mar 2014
- AC C894: 'Author Comment: reply to the comment by M. Sassi, referee', Sylvain OUILLON, 11 Apr 2014

Peer-review completion

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

ED: Reconsider after major revisions (26 Apr 2014) by Paola Passalacqua

AR by Sylvain OUILLON on behalf of the Authors (21 May 2014)

ED: Referee Nomination & Report Request started (23 May 2014) by Paola Passalacqua

RR by John Shaw (08 Jun 2014)

Suggestions for revision or reasons for rejection

Upon my second review of Vu et al. (hess-2013-555), I find the manuscript to be much improved. I find the new “Comparison with Former Studies” and “Boundary Conditions” sections to be a big help in understanding the paper. That said, I still find significant issues with some of the article’s main points and structure. I will ask for major revisions of the paper due to how central my issues are, but I still think that once these issues are addressed it will be a valuable paper.
Despite improvements, I believe that Results and Discussion should be better separated. In my opinion, the results of this paper are model results only. It should be the discussion section where the model results are compared with other findings. Vu et al. did not produce any results on siltation of estuaries or erosion and accretion along the Red River Delta. I therefore believe that these sections (4.4 and 4.5) should be moved to the discussion.
The authors have done a good job developing a model that suggests changes in water and sediment flux partitioning on the Red River Delta. These results by themselves warrant publication in my opinion. However, the relation between these model results and coastal erosion still need work. In Section 4.5, it is not clear what the effect of the dam has been on coastal change, although several studies are cited. Is there a way to compare the quantitative output of the MIKE11 model to changes in rates? If so, it would be extremely valuable. As the paper currently reads, the output of the model has not increased our understanding of coastal erosion beyond the previous studies.
Let me repeat that the model outputs are themselves valuable and their predictions could lead to improved tests of the dam’s importance to coastal processes and morphology. It is fine to suggest qualitative relationships in the Discussion section, but the current paper does not provide new results on coastal morphology.
I have found several instances where the numbers given in the Tables do not match the numbers in the text. Examples are the numbers in line 405. These should be double and triple checked before publication.
On to smaller comments:
Line 66, 138, 176: I suspect that the measurements were of suspended sediment flux. It is important to state what type of sediment flux is being measured.
In lines 78-86, the authors describe previous studies on changes to coastal sediment transport. This would be a good place to also mention changes in coastal erosion and sedimentation rates.
Line 159, “14 day cycle.”
Line 166, “since they may alter the discharge division amongst distributaries by several percent” (a suggestion)
Line 296, it is difficult to compare the 1.5 m below the surface and above the bed. It would be better to reference all data to above the bed, or below the surface.
Line 327, 0.2 mm s-1 corresponds to what grain size, has grainsize within the delta been published?
Line 331, I am not fully qualified to evaluate this model, but I don’t understand how a rate of erosion could be set completely independently of shear stress.
Line 360, “annual” water distribution
Line 376, the first two paragraphs in Section 4.2 should be combined.
Line 447, We switch from cubic meters to tons between sentences. Perhaps provide both quantities (one in parenthesis) to allow better comparisons.
Line 592, While I applaud the creation of the Boundary Conditions section, I think it can be significantly expanded. How would the increased boundary condition SSC at river mouths change model outputs?

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RR by Maximiliano Sassi (12 Jun 2014)

Suggestions for revision or reasons for rejection

Re-review of 'Impact of the Hoa Binh Dam (Vietnam) on water and sediment budgets in the Red basin and delta' by Vu et al.

The manuscript significantly improved. Section 3.3.1 lacks information on the sediment transport module. For example, how are deposition and erosion fluxes described ? Is there limited sediment availability in the bed ? How many sediment classes are there being used ? I suggest expanding this section, perhaps breaking it down in two parts, one dealing with hydrodynamics and the other dealing with sediment transport. I include below a few more minor corrections.

29-31, it is unclear what you mean by 'the coupling between …'
78, please add comma after 'consequences'
87, do you mean 'complementing' ?
92, 'no systematic record exists' ?
164, 'inferred' is strange within this context, perhaps 'induced' ?
168, citation is not in reference list
169, concerning sediment division mechanisms see Sassi et al. (2013) Sediment discharge division at two tidally-influenced bifurcations, WRR
180, 'and the tide is'
222-224, the given precision is unrealistically high, consider lowering significant figures in reported values
250, 'set up'
265-268, information is missing concerning the sediment transport module
270, 'set up'
286, perhaps mention that in the following paragraphs you explain why you chose to fix the boundary condition during flood
291, mg per liter is missing after the value 61
307, which model parameters?
326, is there only one sediment class?
329, you should mention how calibration is done, I guess in the same manner as for roughness, and using eq. 5 but adapted for concentration, please mention
451-468, this paragraph presents no information about results and therefore should belong to the discussion section or the introduction
565, the wording 'low energetic episodes' is unclear, please consider rephrasing
583, 'may be superimposed'
593-596, you can safely place this piece of text after line 302
610, please add a comma after 'subsidence'
620, these references in the conclusion section may not be necessary

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ED: Reconsider after major revisions (23 Jun 2014) by Paola Passalacqua

AR by Sylvain OUILLON on behalf of the Authors (29 Aug 2014) Author's response Manuscript

ED: Publish subject to minor revisions (Editor review) (09 Sep 2014) by Paola Passalacqua

AR by Sylvain OUILLON on behalf of the Authors (10 Sep 2014) Author's response Manuscript

ED: Publish as is (10 Sep 2014) by Paola Passalacqua

AR by Sylvain OUILLON on behalf of the Authors (11 Sep 2014)