Effect of Land-Use Change on Runoff in Hyrcania

Round 1

Reviewer 1 Report

GENERAL COMMENTS

The manuscript has improved significantly since the initial version. However, there are still some issues that should be addressed.

- The authors have not made clear why they have chosen the SCS-CN method. In the Introduction section, the models AGNPS, EPIC, SWAT, and WMS are mentioned, and right afterwards the choice of SCS-CN is announced, justified by its popularity. However, SCS-CN, from a methodological point of view, is very different compared to the aforementioned models. AGNPS, SWAT and WMS are distributed physically-based models, whereas EPIC is a cropping systems model. On the other hand, SCS-CN is a conceptual hydrological model. For this reason, the reference to these four models makes no sense. Instead, references to conceptual hydrological models should be included here, for example HYMOD2 (Roy et al. 2017) or LRHM (Rozos, 2019).

- The text needs polishing (see examples in the specific comments).

- There is an issue with text copied from another source (soil classes). Though properly referenced, it is not a good practice to copy extended parts, especially since this text can nowadays be found easily (see specific comments).

SPECIFIC COMMENTS

Location: "...  remote sensing data and GIS tools allows ..."
Comment: allows -> allow

Location: "The GIS environment facilitates the integration of different data sources and perform ..."
Comment: perform -> performs

Location: Table 2
Comment: The text of this table can be found in reference [31] of the manuscript. There is absolutely no reason to reproduce it here.

Location: "land use", scattered all over the text
Comment: If it is used as an adjective, it should be "land-use", as it is correctly used occasionally, but not consistently throughout the text.

REFERENCES

Roy, T., et al., 2017. Using satellite-based evapotranspiration estimates to
improve the structure of a simple conceptual rainfall-runoff model.  Hydrology and Earth System Sciences, 21 (2), 879–896. doi:10.5194/hess-21-879-2017

Rozos, E., 2020. A methodology for simple and fast streamflow modelling. Hydrological Sciences Journal, 65(7), pp.1084-1095.

Author Response

Review 1

The manuscript has improved significantly since the initial version. However, there are still some issues that should be addressed.

Comment: The authors have not made clear why they have chosen the SCS-CN method. In the Introduction section, the models AGNPS, EPIC, SWAT, and WMS are mentioned, and right afterwards the choice of SCS-CN is announced, justified by its popularity. However, SCS-CN, from a methodological point of view, is very different compared to the aforementioned models. AGNPS, SWAT and WMS are distributed physically-based models, whereas EPIC is a cropping systems model. On the other hand, SCS-CN is a conceptual hydrological model. For this reason, the reference to these four models makes no sense. Instead, references to conceptual hydrological models should be included here, for example HYMOD2 (Roy et al. 2017) or LRHM (Rozos, 2019).

Response: This part of the text was modified following the reviewer’s suggestion. We no longer mention AGNPS etc. Instead, we mention HYMOD and LHM and refer to Roy et al. and Rozoz.

Comment: The text needs polishing (see examples in the specific comments).

Response: The text was polished

Comment: There is an issue with text copied from another source (soil classes). Though properly referenced, it is not a good practice to copy extended parts, especially since this text can nowadays be found easily (see specific comments).

Response: Table 2 (soil hydrologic groups) was removed because in the specific comments it is mentioned that there is no need to reproduce it.

SPECIFIC COMMENTS

Comment: Location: "...  remote sensing data and GIS tools allows ..." allows -> allow

Response: Corrected.

Comment: Location: "The GIS environment facilitates the integration of different data sources and perform ..." perform -> performs

Response: Corrected.

Comment: The text of this table (Table 2) can be found in reference [31] of the manuscript. There is absolutely no reason to reproduce it here.

Response: Table 2 (soil hydrologic groups) was removed.

Comment: Location: "land use", scattered all over the text. If it is used as an adjective, it should be "land-use", as it is correctly used occasionally, but not consistently throughout the text.

Response: Corrected throughout the manuscript (now systematically: land use, land-use change).

Comment: REFERENCES

Roy, T., et al., 2017. Using satellite-based evapotranspiration estimates to improve the structure of a simple conceptual rainfall-runoff model.  Hydrology and Earth System Sciences, 21 (2), 879–896. doi:10.5194/hess-21-879-2017

Rozos, E., 2020. A methodology for simple and fast stream flow modelling. Hydrological Sciences Journal, 65(7), pp.1084-1095.

Reviewer 2 Report

Dear Editor.

I have finished my review on the proposed paper “Effect of land-use change on runoff in Hyrcania” land-1569329-peer-review-v1.

Summary of the manuscript:

In the proposed paper, the authors’ goal is to evaluated the effect of land-use changes on runoff over 15 years in a study area in North Iran. They used remote sensing data and GIS techniques combined with the SCS-CN runoff model. The results showed that most of the increase in runoff was related to the increased area of bare land and decreased area of rangeland.

General review:

1. Generally, the manuscript presents a very interesting topic and the specific research seems to include some significant points for the research community of this field.
2. The proposed paper is very well written with very good use of English language. Except some minor grammatical mistakes and word errors, this paper is written with a very good scientific style. The authors should check again the paper to correct these minor mistakes.
3. The proposed paper is very well structured. It begins with an analytical Introduction with the appropriate references that helps the reader to get into the subject immediately. In Introduction there is an effort to provide previous studies with similar scientific content, which took place in the research area and in some cases in other countries. Authors describe and set very well the scientific problem and how other researchers have approached. At the end of Introduction, authors clearly state the goals of the research.
4. The methodology is generally very interesting, and well explained, so other researchers could easily repeat it. Every aspect of methodology is well documented with the use of the appropriate literature. However, I have some concerns, which are explained below.
5. The results scientifically explained with the use of the appropriate scientific literature.
6. The quality of the work in Discussion section is very high and qualitative.
7. Conclusions are appropriate for this paper.

Points for revision:

In my opinion, the proposed paper could be characterized as a very good research work, complies with aims of Land. 

Nevertheless, I have some points for revision.

Lines 38-41: In this paragraph you use “rainfall”. However, I think that is better to use “precipitation”. As I read in the text, you use mostly the “precipitation”, which is the correct word.

Lines 51-54: Here, you should highlight a very significant aspect that influence the runoff from forest environments. “It is known that forests present finite capabilities to retain large amounts of precipitation, especially during extreme rainfall events, even if the forest cover percentage is significantly high” (Kastridis et al. 2021, De Jong 2016). So, the runoff is highly influenced from rainfall intensity and the forest sometimes are not capable to retain much of the rainfall. Add a phrase in the text addressing the above, using the proposed literature.

2.4. and 2.5 sections: Here, you presented the known SCS classes for hydrological soil groups to estimate the CN. In 2.5 you inform us about the rainfalls and the calculation of R using the initial abstraction (0.2S) in the equation. However, the presented calculation of CN and respectively of R, is for standard initial soil moisture conditions. More specifically, you calculated the CNII for initial loss rate of 20%, which is the reference value and corresponds to average humidity conditions (Antecedent Moisture Conditions, (AMC II)). But, throughout the year the AMC is changing. The runoff generation is significantly different during the wet period when the soli moisture is higher, in comparison to the drought season when the soil moisture in lower. For that reason, when CN is estimated the AMC is taken into account according the following table (Chow et al. 1988):

Classification of antecedent moisture condition classes (AMC) for the SCS method of rainfall abstractions (source: Chow et al. 1988; table 5.5.1, p. 149).

You calculate the runoff with the same value of CN for all the seasons of the year. I think that you should make some changes to your results.

Lines 189-193: “….where the curve number (0 ≤ CN ≤ 100) represents…”. The lowest value of CN is 30 (dense forest with good soil) according to the TR-55 (USDA 1986). Zero values are for open waters (lakes, reservoirs…), but these areas do no contribute to the runoff. So, I think that you should change it, and not take into account the open waters.

Figure 2: The color pallet is not very good. The 3 and the 9 are almost the same. If you can change some colors, in order the figure to be more clear.

Chow V.T., Maidment D.R. and Mays L.W. (1988), Applied Hydrology, McGraw‐Hill: New York, NY, USA, 1988, p. 572, ISBN 0 07‐010810‐2.

De Jong, C. European perspectives on forest hydrology. In Forest Hydrology: Processes, Management and Assessment; Amatya, D., Williams, T., Bren, L., De Jong, C., Eds.; CABI:Wallingford, UK, 2016; pp. 69–87.

Kastridis, A.; Theodosiou, G.; Fotiadis, G. Investigation of Flood Management and Mitigation Measures in Ungauged NATURA Protected Watersheds. Hydrology 2021, 8, 170. https://doi.org/10.3390/hydrology8040170.

United States Department of Agriculture (USDA) 1986. Urban Hydrology for Small Watersheds. Technical Release 55. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044171.pdf

Author Response

Review 2

Summary of the manuscript:

In the proposed paper, the authors’ goal is to evaluate the effect of land-use changes on runoff over 15 years in a study area in North Iran. They used remote sensing data and GIS techniques combined with the SCS-CN runoff model. The results showed that most of the increase in runoff was related to the increased area of bare land and decreased area of rangeland.

 General review:

1. Generally, the manuscript presents a very interesting topic and the specific research seems to include some significant points for the research community of this field.
2. The proposed paper is very well written with very good use of English language. Except some minor grammatical mistakes and word errors, this paper is written with a very good scientific style. The authors should check again the paper to correct these minor mistakes.

Response: The paper was thoroughly checked and several minor mistakes were corrected.

3. The proposed paper is very well structured. It begins with an analytical Introduction with the appropriate references that helps the reader to get into the subject immediately. In Introduction there is an effort to provide previous studies with similar scientific content, which took place in the research area and in some cases in other countries. Authors describe and set very well the scientific problem and how other researchers have approached. At the end of Introduction, authors clearly state the goals of the research.
4. The methodology is generally very interesting, and well explained, so other researchers could easily repeat it. Every aspect of methodology is well documented with the use of the appropriate literature. However, I have some concerns, which are explained below.
5. The results scientifically explained with the use of the appropriate scientific literature.
6. The quality of the work in Discussion section is very high and qualitative.
7. Conclusions are appropriate for this paper.

Points for revision:

In my opinion, the proposed paper could be characterized as a very good research work, complies with aims of Land.

Nevertheless, I have some points for revision.

Comment: Lines 38-41: In this paragraph you use “rainfall”. However, I think that is better to use “precipitation”. As I read in the text, you use mostly the “precipitation”, which is the correct word.

Response: Rainfall changed into precipitation.

Comment: Lines 51-54: Here, you should highlight a very significant aspect that influence the runoff from forest environments. “It is known that forests present finite capabilities to retain large amounts of precipitation, especially during extreme rainfall events, even if the forest cover percentage is significantly high” (Kastridis et al. 2021, De Jong 2016). So, the runoff is highly influenced from rainfall intensity and the forest sometimes are not capable to retain much of the rainfall. Add a phrase in the text addressing the above, using the proposed literature.

Response: Text about this aspect and the suggested references were added.

Comment: 2.4. and 2.5 sections: Here, you presented the known SCS classes for hydrological soil groups to estimate the CN. In 2.5 you inform us about the rainfalls and the calculation of R using the initial abstraction (0.2S) in the equation. However, the presented calculation of CN and respectively of R, is for standard initial soil moisture conditions. More specifically, you calculated the CNII for initial loss rate of 20%, which is the reference value and corresponds to average humidity conditions (Antecedent Moisture Conditions, (AMC II)). But, throughout the year the AMC is changing. The runoff generation is significantly different during the wet period when the soil moisture is higher, in comparison to the drought season when the soil moisture in lower. For that reason, when CN is estimated the AMC is taken into account according the following table (Chow et al. 1988):

Classification of antecedent moisture condition classes (AMC) for the SCS method of rainfall abstractions (source: Chow et al. 1988; table 5.5.1, p. 149).

AMC group     Total 5-day antecedent rainfall (mm)

                      Dormant season                   Growing season

I                     Less than 13   Less than 35

II                    13 to 28          35 to 53

III                   Over 28          Over 53

You calculate the runoff with the same value of CN for all the seasons of the year. I think that you should make some changes to your results.

Response: Certainly, if AMC and the effect of dry and wet seasons had been considered in both periods, the results would have been closer to reality. However, or results are more general and averaged, mainly due to the lack of detailed information on AMC and growing season. Note, for example, that we used the same distribution of rain event intensities in both years, and this distribution was an average of several weather station from several years. The wetness conditions certainly vary between years, locations and also during the year, but our data did not allow to take this variation into account. On the other hand, we analysed the sensitivity of the results to the initial abstraction parameters and noticed that a substantial change in the parameter value dos not alter the main conclusion of the study. However, we now mention the AMC issue in discussion and refer to Chow et al. 1988.

Comment: Lines 189-193: “….where the curve number (0 ≤ CN ≤ 100) represents…”. The lowest value of CN is 30 (dense forest with good soil) according to the TR-55 (USDA 1986). Zero values are for open waters (lakes, reservoirs…), but these areas do no contribute to the runoff. So, I think that you should change it, and not take into account the open waters.

Response: We did not have open waters in the study area and we did not involve the associated CN. This section shows the CN range and formula of the calculations in general.

Comment: Figure 2: The color pallet is not very good. The 3 and the 9 are almost the same. If you can change some colors, in order the figure to be clearer.

Response: The color palette used in Figure 2 was changed to make the figure clearer.

Comment: Chow V.T., Maidment D.R. and Mays L.W. (1988), Applied Hydrology, McGraw‐Hill: New York, NY, USA, 1988, p. 572, ISBN 0 07‐010810‐2.

De Jong, C. European perspectives on forest hydrology. In Forest Hydrology: Processes, Management and Assessment; Amatya, D., Williams, T., Bren, L., De Jong, C., Eds.; CABI:Wallingford, UK, 2016; pp. 69–87.

Kastridis, A.; Theodosiou, G.; Fotiadis, G. Investigation of Flood Management and Mitigation Measures in Ungauged NATURA Protected Watersheds. Hydrology 2021, 8, 170. https://doi.org/10.3390/hydrology8040170.

United States Department of Agriculture (USDA) 1986. Urban Hydrology for Small Watersheds. Technical Release 55. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044171.pdf

Response: We now refer to the studies by Chow et al., De Jong and Kastridis et al.

Round 2

Reviewer 1 Report

The authors have addressed successfully all my comments/suggestions.

Author Response

Reviewer 1 did not provide new comments

Reviewer 2 Report

Dear authors.

Thank you very much for your responses. However, I have some points that I want to be more clear.

Comment: Lines 51-54: Here I proposed to add a small phrase, which I put it in quotations ("...."). You have added it. However, you should rephrase this phrase, because it was copied from the original paper.  Also, here I proposed to add 2 papers for literature. But the one paper that you added (Kastridis et al. 2020) is wrong. I proposed "Kastridis et al. 2021. See the reference list.

Comment: Lines 189-193: "We did not have open waters in the study area and we did not involve the associated CN. This section shows the CN range and formula of the calculations in general." 

Now you confused me. In figure 2 and table 4, what you mean with the code "9 water"??? As i can see from google earth there is a lake there (Lar dam). Please explain.

Also, from the current literature the write is 30≤CN≤100, as I told you in previous comment.

Author Response

Comment: Lines 51-54: Here I proposed to add a small phrase, which I put it in quotations ("...."). You have added it. However, you should rephrase this phrase, because it was copied from the original paper.  Also, here I proposed to add 2 papers for literature. But the one paper that you added (Kastridis et al. 2020) is wrong. I proposed "Kastridis et al. 2021. See the reference list.

Response: The text was modified and the reference was corrected

Comment: Lines 189-193: "We did not have open waters in the study area and we did not involve the associated CN. This section shows the CN range and formula of the calculations in general." 

Now you confused me. In figure 2 and table 4, what you mean with the code "9 water"??? As i can see from google earth there is a lake there (Lar dam). Please explain.

Also, from the current literature the write is 30≤CN≤100, as I told you in previous comment.

Response: Sorry for the mistake, there is one water area. However, it was not included in the runoff calculation (see Figure 5, which does not include water). The CN range is now written as 30≤CN≤100

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The relationship between runoff and LULC is a very interesting topic of research. In this case, I do not feel the authors are contributing significantly to this topic. This manuscript is rather a technical report than a research paper. The authors just use some existing methods and basic GIS tasks to produce a series of maps and carry out descriptive comparisons between them. This seems insufficient to me. More detailed comments are below:

1) Line 25: This statement is argueable as it is. Please, rephrase or support with references.

2) The introduction section lacks a part devoted to literature review. A lot of studies have been developed in the past to assess the influence of LULC changes on runoff. The authors should revise them and highlight their limitations, while justifying the need for developing this study as a means to overcome such shortcomings. Otherwise, the contributions and originality of this manuscript are currently missing.

3) Line 90: There is a legend in the map. This description about the elevation is completely unnecessary.

4) Table 1: There is a typo error. It should be 1996.

5) Should not this refinement process be moved to the results? Also, provide more details about this accuracy assessment and the goodness-of-fit measures used to test it.

6) The explanation about how HSGs were allocated needs to be expanded as well. This is crucial and the authors provide very shallow explanations about this. Did you calculate it from the Landsat maps. How did you determine soil texture? Describe the relationship between soil texture and HSG explicitly.

7) Again, Table 4 seems to belong to results to me. Please, carefully revise the organization of the whole manuscript and improve the distribution of your contents, so that they appear in their corresponding section.

8) Figures and tables must be self-understandable. Please, include the description of each land use type in the legend of Figure 3.

9) Table 5: What about conducting statistical tests (Student's t or Mann-Whitney) to check whether these changes are statistically significant or not? This would notably increase the meaningfulness of the results achieved. 

10) Figure 4's caption must be rephrased. It does not correspond with the map.

11) Please, merge Figure 5 and 6 to obtain Figure 5 (a: depth; b: volume).

12) Lines 230-232: Going back to my second comment, this sentence does not help justify the need for the study.

13) The conclusions are missing. The authors should include this section to present the main findings derived from their study, as well as their implications for this field of research and land use / water management. Also the limitations of the ivnestigations should be highlighted, while proposing some lines of research to continue working in this area.

Reviewer 2 Report

I don't have much to say about this contribution. overall , it is well written, referenced, grammatically correct, formally sound and results supported by the data analyses and approach. A few minor changes as per below and it can be accepted. 

Abstract: 'Population explosion and increased human activities have resulted in drastic changes in 9 land use, affecting the hydrological processes of water basins'. are we talking globally or locally? this sentence is correct but seems to be disconnected with the following one int he abstract. maybe rephrase it?

'Landsat images were used to develop land use maps for 1996 12 and 2011' this sentence is not clear. are we using two snapshots only (i.e., the two years) or the time series of Landsat images? from the previous sentences I would say the time series. Maybe rephrase this part?

Introduction: 'Rainfall is the main source of water' - globally or regionally? 

l36. typo (increasing tee' should be increasing the')

Reviewer 3 Report

This manuscript concerns a study on the impact of land-use change on runoff in Hyrcania. The study has employed standard methods: Landsat images of years 1996 and 2011, classification to land-use classes, and the "curve number" method of the Soil Conservation Service. Though the manuscript is well-written and structured, it does not make clear what was the motivation and the lessons obtained from this study. Remarkably, the manuscript does not have a Conclusions section. The current form of the manuscript presents the authors' work as a typical hydrological application and, hence, does not present broad scientific interest. The authors need to rewrite the manuscript to highlight what are the transferable lessons obtained from their study, which would be useful to other researchers.