Climate Change Impacts on Surface Runoff and Nutrient and Sediment Losses in Buchanan County, Iowa

Round 1

Reviewer 1 Report

The manuscript investigates the effects of climate change on surface runoff and nutrient and sediment losses in Buchanan County, Iowa, using an ecohydrological model and CIMIP5 scenarios.

The paper is interesting and well-written. But the authors may consider the following issues.

Line 56-58: I think these questions are not the main issue of the manuscript. So, I suggest to remove them. Instead, you may focus on your main issue and aim of your study.

There is no figure of the study area.

You may use the CIMIP6 climate scenarios. It can be part of your novelty.

The tables can be presented in a better way or replaced by figures to be interpreted easier.

The role of human activities may be discussed (or assessed) in the manuscript.

The paper is interesting and well-written. I just have one question which can be considered by the authors as a suggestion. But I do not force them to do it. 

I am wondering if the climate investigation can be conducted by the CMIP6 climate models. It may increase the novelty of the study.   

Author Response

Responses to Comments by Reviewer 1:

The manuscript investigates the effects of climate change on surface runoff and nutrient and sediment losses in Buchanan County, Iowa, using an ecohydrological model and CIMIP5 scenarios.

The paper is interesting and well-written. But the authors may consider the following issues.

Comment 1 by Reviewer 1:

Line 56-58: I think these questions are not the main issue of the manuscript. So, I suggest to remove them. Instead, you may focus on your main issue and aim of your study.

Response:

Many thanks to the reviewer. It is true that at least one of those questions was not relevant as stated. We have revised that section to provide questions that are directly relevant to this study, particularly relating to nutrient source (manure versus inorganic fertilizer) and crop rotation.

Comment 2 by Reviewer 1:

There is no figure of the study area.

Response:

Thanks again. We have now included a “Study Area” section that includes, among others, a figure for the area studied.

Comment 3 by Reviewer 1:

You may use the CIMIP6 climate scenarios. It can be part of your novelty.

Response:

Thank you for the suggestion. That is a very good idea and we plan on doing that at some point in the future. Unfortunately, we are unable to use the CMIP6 data at this time – for this specific paper. Inclusion of CMIP5 for this study entailed substantial validation tests that we are unable to replicate within reasonable time for this paper. We do appreciate the suggestion and plan on utilizing CMIP6 data in the near future.

Comment 4 by Reviewer 1:

The tables can be presented in a better way or replaced by figures to be interpreted easier.

Response:

Thanks very much. We replaced Tables 10 – 12 and now have graphs in their stead – Figures 6 – 8.

Comment 5 by Reviewer 1:

The role of human activities may be discussed (or assessed) in the manuscript.

Response:

Thank you. We have included discussion of the role of human activities in surface runoff, wherein we show how the climate patterns are a more significant driver of the surface runoff dynamics than any direct impacts of human activities.

Comment 6 by Reviewer 1:

The paper is interesting and well-written. I just have one question which can be considered by the authors as a suggestion. But I do not force them to do it.

I am wondering if the climate investigation can be conducted by the CMIP6 climate models. It may increase the novelty of the study.  

Response:

Thanks again. As mentioned above, we plan on using CMIP6 at some point in the near future, but not for this specific paper.

Reviewer 2 Report

In general, the article is well presented, rigorously from a scientific point of view, it is interesting and relevant to the journal. But some minor revisions are needed.
I recommend making the tables homogeneous by choosing either a dot or a comma for decimal numbers.

Author Response

Responses to Comments by Reviewer 2:

In general, the article is well presented, rigorously from a scientific point of view, it is interesting and relevant to the journal. But some minor revisions are needed.

Comment 1 by Reviewer 2:

I recommend making the tables homogeneous by choosing either a dot or a comma for decimal numbers.

Response:

Thanks. We actually made some corrections in the table that might have made them confusing. We also replaced three tables with three corresponding figures to make the results section more readable.

Reviewer 3 Report

This study investigated the effects of climate change (by looking at changes in precipitation and runoff) on nutrient and sediment losses in Buchanan County, Iowa.

Overall, the paper has a logical structure, and it is well-written. However, the authors must first apply the following concerns.

1- Two questions are provided in lines 56-58. Does the article intend to answer them? (probably not). Therefore, it is necessary to edit them (or delete them) or provide answers to these questions based on your result and discuss them.

2- State the research question clearly at the end of the introduction section.

3- It is necessary to present the study area in a specific section (Study Area) by using a comprehensive figure that shows different characteristics of the study area ( such as elevation, coordination,  agricultural area, urban area, river, ...).

4- The authors have studied the historical and future precipitation and its effect on runoff resulting from climate change. But, the runoff change is not only due to climate change and human activity. And human activity introduces by different research as the primary driver of runoff changes. Thus,  it cannot be ignored such this paper did. The authors should consider the effect of human activity on runoff change as an essential variable in nutrient and sediment concentration/losses. 

5- the result section involved an enormous number of tables. And it isn't easy to interpret them. I recommend that they be summarized or replaced with the graph.

Author Response

Responses to Comments by Reviewer 3:

This study investigated the effects of climate change (by looking at changes in precipitation and runoff) on nutrient and sediment losses in Buchanan County, Iowa.

Overall, the paper has a logical structure, and it is well-written. However, the authors must first apply the following concerns.

Comment 1 by Reviewer 3:

1- Two questions are provided in lines 56-58. Does the article intend to answer them? (probably not). Therefore, it is necessary to edit them (or delete them) or provide answers to these questions based on your result and discuss them.

Response:

Thanks for pointing this out. We agree and have revised that section, using questions that are directly relevant to this study – specifically questions dealing with nutrient source and crop rotation, aspects we address in the paper.

Comment 2 by Reviewer 3:

2- State the research question clearly at the end of the introduction section.

Response:

Thanks. We have now clearly stated the research question at the end of the “Introduction” section.

Comment 3 by Reviewer 3:

3- It is necessary to present the study area in a specific section (Study Area) by using a comprehensive figure that shows different characteristics of the study area ( such as elevation, coordination,  agricultural area, urban area, river, ...).

Response:

Thanks very much. We have now included a “Study Area” section, which also includes a figure.

Comment 4 by Reviewer 3:

4- The authors have studied the historical and future precipitation and its effect on runoff resulting from climate change. But, the runoff change is not only due to climate change and human activity. And human activity introduces by different research as the primary driver of runoff changes. Thus,  it cannot be ignored such this paper did. The authors should consider the effect of human activity on runoff change as an essential variable in nutrient and sediment concentration/losses.

Response:

Thanks. We have now addressed the role of human activities and have also included in the discussion, how these direct anthropogenic effects compare to climate change impacts in terms of magnitude.

Comment 5 by Reviewer 3:

5- the result section involved an enormous number of tables. And it isn't easy to interpret them. I recommend that they be summarized or replaced with the graph.

Response:

Thanks again. We have replaced three tables (Tables 10 – 12) with Figures 6 – 8 to make the results section less tedious. We also broke the “Results and Discussion” section into subsections to make it more manageable to the average reader.

Round 2

Reviewer 3 Report

I dont have further comments