A Streamlined Methodology for Identifying Point-Source Inputs from Rural and Agricultural Sources
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors:
Thank you for submitting your work to Sustainability.
Please find several recommendations to improve the quality of this manuscript:
1. Introduction: This section has explained the main content, including background information and research questions. However, the significance of this research is not explicitly stated. The authors are strongly encouraged to emphasize the importance of their work in relation to previous research.
2. Setting: It is important to emphasize the rationale of choosing the research object. In addition, the authors might add some comparisons or any specialties of choosing that object instead of others.
3. Methodology: This section is the point that brings novelty of this research. What does the scientific method used by the authors? That novel method need to be clearly stated in order to guarantee the replication for future research. Instead, I found the authors only cited references without any scientific justification.
4. Results: Since the previous section (methodology) is not clear to state the scientific method used, thus, it is not clear as well the design and step of discussion performed in this section. It is difficult for readers to understand the information that authors want to convey.
5. Discussion: This section also does not support the results. For instance, in Line 410, how do the correlation index find, i.e., r = 0.78? In fact, we cannot find any calculation or data related to that finding. Subsection 5.4 could be moved to the conclusion.
6. References: Numerous references are not from reputable journal paper, instead of websites that its validity cannot be guaranteed. Even, the authors cited the journal paper, but most of them are outdated. A good paper must cite recent publications, that comes maximum from 8 years back.
7. Others: Please write the title of all figures in an appropriate way. The figure title must be clear and concise. Additionally, please improve the improve of writing, such as Lines 44, 196: "this is why" could be replaced by "this is the reason of...". Check for others and do a proofread. Further, the used of capital letter in the middle of sentence is needed to be checked, such as Line 327 "Km". Line 193: typo "[l]iquid"
NB: I do not recommend this submission as a scientific paper, instead it is a kind of general report. There is no novel and scientific method that can be reproduced for future research.
Author Response
Comment 1. Introduction: This section has explained the main content, including background information and research questions. However, the significance of this research is not explicitly stated. The authors are strongly encouraged to emphasize the importance of their work in relation to previous research.
Response 1. We agree that the significance of our research in the introduction is not as explicit as it should be. In short, few, if any peer-reviewed studies have proposed field-based methodology that targets point-source inputs in an agriculturally-impacted watershed. We are proposing a streamlined set of methods and techniques that, when implemented will result in better water quality and more sustainable practices.
Comment 2: Setting: It is important to emphasize the rationale of choosing the research object. In addition, the authors might add some comparisons or any specialties of choosing that object instead of others.
Response 2: Agreed. We hope our revisions have addressed this.
Comment 3. Methodology: This section is the point that brings novelty of this research. What does the scientific method used by the authors? That novel method needs to be clearly stated in order to guarantee the replication for future research. Instead, I found the authors only cited references without any scientific justification.
Response 3: Agreed. This was cumbersome and unwieldy. We have cut out some “fat” and reorganized it in a way that should lay a logical foundation from which our results are interpreted.
Comment 4: Results: Since the previous section (methodology) is not clear to state the scientific method used, thus, it is not clear as well the design and step of discussion performed in this section. It is difficult for readers to understand the information that authors want to convey.
Comment 5. Discussion: This section also does not support the results. For instance, in Line 410, how do the correlation index find, i.e., r = 0.78? In fact, we cannot find any calculation or data related to that finding. Subsection 5.4 could be moved to the conclusion.
Response 4 and 5: Agreed in every respect. We moved the discussion to “Results and Discussion” section as it seemed more efficient and much clearer to present results and explain their significance at the same time. Also, the r = 0.78 was found at the top of Figure 8 on a table. However, we have eliminated Figure 8 from our new manuscript.
Response 6. References: Numerous references are not from reputable journal paper, instead of websites that its validity cannot be guaranteed. Even, the authors cited the journal paper, but most of them are outdated. A good paper must cite recent publications, that comes maximum from 8 years back.
Comment 6: We removed most of the online references and kept those that refer to specific laws and regulatory documents - which are the only way to access them. We updated our references to be as close to 8 years or newer as possible. There are cases in which we must reference earlier work, but a vast majority of our references are now newer and when possible, we included scholarly papers instead of online sources.
Response 7. Others: Please write the title of all figures in an appropriate way. The figure title must be clear and concise. Additionally, please improve the improve of writing, such as Lines 44, 196: "this is why" could be replaced by "this is the reason of...". Check for others and do a proofread. Further, the used of capital letter in the middle of sentence is needed to be checked, such as Line 327 "Km". Line 193: typo "[l]iquid"
Comment 7. Figures are properly titled and more explanation has been added. Other references mentioned in this response have been changed or removed.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript addresses an important watershed management problem and assembles monitoring, simple statistics and GIS interpretation into a “streamlined methodology” to diagnose agricultural point sources. However, the methodological novelty, statistical rigor, hydrological context and source attribution remain insufficiently developed to support the strength of the conclusions. Substantial technical revision and clearer methodological framing are required; I therefore recommend major revision.
- The claimed “streamlined methodology” is not yet clearly distinguished from standard monitoring and TMDL practice; the authors should explicitly formalize the workflow and state what is genuinely new and generalizable.
- The spatial–temporal sampling design is not transparent.
- QA/QC procedures for replicates and outliers, detection limits, blanks and calibration checks need to be described and justified quantitatively, including how many data points were re-run or discarded and how censored data were treated.
- The use of E. coli peaks and co-occurring nutrients to rule out chemical fertilizers and septic sources is plausible but not definitive.
- The rainfall-lag argument used to distinguish CAFO runoff from septic leakage is currently qualitative.
- References to explicit regulatory thresholds and exceedances are currently qualitative; a concise table listing relevant SRP, NH3–N and E. coli standards, along with the frequency and magnitude of exceedance at each site, is needed to support the regulatory conclusions.
- The discussion of mitigation and restoration options would benefit from a more technical treatment of vegetative and wetland-based measures; for example, integrating insights from studies such as “Dual effects of Caragana korshinskii introduction on herbaceous vegetation in Chinese desert areas: short-term degradation and long-term recovery” and “Lanthanum-quaternized chitosan-modified zeolite for long-lasting operation of constructed wetland: A bifunctional strategy for simultaneous phosphorus removal and microbial clogging mitigation” could better connect source diagnosis with ecological remediation strategies.
- To frame future management and research directions, a brief paragraph on advanced treatment options for polluted rural waters would be useful; in this context, works like “Preparation of Ce–Feâ‚‚O₃/Alâ‚‚O₃ catalyst for simultaneous degradation of benzodiacetone and reduction of Cr(VI) by electro-Fenton process: Performance, mechanism, degradation pathways” and “Soft/hard interface design of bismuth nanodots embedded in Ti₃Câ‚‚Tx MXene for highly efficient dechlorination battery deionization” could be cited as examples of emerging high-efficiency treatment technologies.
- Finally, a concise limitations and generalizability section is needed, explicitly acknowledging the single-watershed setting, the reliance on concentration (not load) data, the absence of source-specific tracers, the limited number of events, and the partly qualitative image analysis, together with a plan for validating this methodology elsewhere.
Author Response
Comment 1: The claimed “streamlined methodology” is not yet clearly distinguished from standard monitoring and TMDL practice; the authors should explicitly formalize the workflow and state what is genuinely new and generalizable.
Response 1: We recognize this and have tried to address what we mean by “streamlined” – and differentiate it from TMDLs
Comment 2: The spatial-temporal sampling design is not transparent
Response 2: We have tried to make this more understandable. It is a novel approach that is not often discussed in the literature.
Comment 3: QA/QC procedures for replicates and outliers, detection limits, blanks and calibration checks need to be described and justified quantitatively, including how many data points were re-run or discarded and how censored data were treated.
Response 3: We feel these are addressed in the new manuscript.
Comment 4: The use of E. coli peaks and co-occurring nutrients to rule out chemical fertilizers and septic sources is plausible but not definitive.
Response 4: Agreed. This is why we also investigated fields that were able to accept manure vs. those that used chemical fertilizers. Additionally, if a field uses chemical fertilizers, the spike in nutrients is in the Spring or late Fall, but should not appear in mid-summer. And, if inputs were from leaking septic systems, we should not see nutrient and E. coli spikes after a rain event as we did. We noted this in the new manuscript. Also, we feel there were other checks and balances that would put more weight on the relationship. But, you are correct.
Comment 5: The rainfall-lag argument used to distinguish CAFO runoff from septic leakage is currently qualitative
Response 5: Agreed. Until we have good data on leaky septic system GW migration velocities, we can’t know for certain. A good M.S. thesis?
Comment 6: References to explicit regulatory thresholds and exceedances are currently qualitative; a concise table listing relevant SRP, NH3–N and E. coli standards, along with the frequency and magnitude of exceedance at each site, is needed to support the regulatory conclusions.
Response 6: We thought about this. The new manuscript really only addresses whether or not a point-source impact can be identified. The fact that we can identify drainage from the CAFO to the underground drain is a violation of CWA. But other actions would have to be related to violations of standards. The concentrations of E. coli are certainly over standards, and NH3 concentrations are changing – right now the state is moving from unionized ammonia to total NH3. See what you think in the new manuscript.
Comment 7: The discussion of mitigation and restoration options would benefit from a more technical treatment of vegetative and wetland-based measures; for example, integrating insights from studies such as “Dual effects of Caragana korshinskii introduction on herbaceous vegetation in Chinese desert areas: short-term degradation and long-term recovery” and “Lanthanum-quaternized chitosan-modified zeolite for long-lasting operation of constructed wetland: A bifunctional strategy for simultaneous phosphorus removal and microbial clogging mitigation” could better connect source diagnosis with ecological remediation strategies.
Response 7: We like this a lot! I think that might be the follow-up? I think this paper was addressing the front-end of the issue – what you are discussing is the solutions portion. I wouldn’t mind learning more about this.
Comment 8: To frame future management and research directions, a brief paragraph on advanced treatment options for polluted rural waters would be useful; in this context, works like “Preparation of Ce–Feâ‚‚O₃/Alâ‚‚O₃ catalyst for simultaneous degradation of benzodiacetone and reduction of Cr(VI) by electro-Fenton process: Performance, mechanism, degradation pathways” and “Soft/hard interface design of bismuth nanodots embedded in Ti₃Câ‚‚Tx MXene for highly efficient dechlorination battery deionization” could be cited as examples of emerging high-efficiency treatment technologies.
Response 8; Yes. Agreed. We have tailored the manuscript to be leaner, but follow-up would demand this kind of treatment. Thank you!
Comment 9: Finally, a concise limitations and generalizability section is needed, explicitly acknowledging the single-watershed setting, the reliance on concentration (not load) data, the absence of source-specific tracers, the limited number of events, and the partly qualitative image analysis, together with a plan for validating this methodology elsewhere.
Response 9: We feel we addressed this in the new manuscript. Let us know if more is needed.
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsDear Authors:
Thank you for submitting your revision.
This manuscript has so much improved.
Please find several recommendations to improve the quality of this manuscript:
1. Please write the title of all figures correctly. The figure title must be clear and concise. Usually, the figure's title only consists of one sentence. The rest may be added to the main explanation.
2. Please improve the quality of writing and be consistent. For instance, in Line 74, "Section 505" starts with an uppercase, however, in Line 166, it is written in lowercase. Another one, Lines 148: "p ≤ 0.91" with space after p, but Lines 149: "p≤ 0.88" without space.
3. Please print all mathematical notations in italic, such as Lines 148-149: "p", Lines 209, 210, 214, etc.: "r". Please check the whole manuscript.
4. The title of Figures 10 and 11 must be changed. What is the different between those figures? Instead, the authors may use (a) and (b) and explain the difference.
5. Conclusions: This section could be added with any recommendation for future research.
6. References: Please consider to remove the outdated sources, such as #24 and #32. Find the updated ones.
Author Response
Comment 1: Please write the title of all figures correctly. The figure title must be clear and concise. Usually, the figure's title only consists of one sentence. The rest may be added to the main explanation.
Response 1: All figures have been given titles as per suggestions by the reviewer. Thank you.Comment 2: Please improve the quality of writing and be consistent. For instance, in Line 74, "Section 505" starts with an uppercase, however, in Line 166, it is written in lowercase. Another one, Lines 148: "p ≤ 0.91" with space after p, but Lines 149: "p≤ 0.88" without space.
Response 2: These have been corrected as suggested by reviewer.Comment 3: Please print all mathematical notations in italic, such as Lines 148-149: "p", Lines 209, 210, 214, etc.: "r". Please check the whole manuscript.
Response 3: These have been corrected throughout the manuscript as suggested by reviewerComment 4: The title of Figures 10 and 11 must be changed. What is the different between those figures? Instead, the authors may use (a) and (b) and explain the difference.
Response 4: The difference is that one image is from 2015 and the other from 2024. It is now part of the title and is also in the description.
Comment 5. Conclusions: This section could be added with any recommendation for future research.
Response 5: This has been done. The implication was that this was a fairly controlled study – where we need to apply the suggested methods to a situation in which the impact is a bit more diffuse. Thank you for the suggestion.
Comment 6. References: Please consider to remove the outdated sources, such as #24 and #32. Find the updated ones.
Response 6: The authors had a great deal of discussion about this. We absolutely understand the need for current and relevant referencing. We have removed and replaced outdated (older than 8 years) references and replaced them with newer work that address the same issues from a more recent perspective. However, we feel strongly that five references older than 8 years need to remain. This is because we feel they are pivotal to the point we are making and have not been replicated in exactly the same manner since their initial publication. These include theoretical foundations (i.e. correlating SRP and NH3 to arrive at input proximity; developing and implementing a specific systems approach for rural pollution solutions), as well as studies that express exactly the problems we are addressing. The problem with agricultural pollution in the USA is that it has been occurring (and growing worse) over the past 30 years. The salient research on their impacts has been done and a scientific consensus as to the causes has been established for two decades. This is part of our main point – that despite this consensus, despite the fact we know the specific causes, we still find watershed degradation occurring all over the country. This puts more emphasis on the potential importance of what we are offering – using specific field-based methodology to change how we approach regulating large operations. We hope this is understandable and thank the reviewer for the suggestion.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript has undergone substantial revision, and the technical issues raised in the first review have been well addressed. The overall quality has improved significantly. However, the reference framework remains somewhat limited. It is recommended that the authors consider incorporating the following recent and relevant works into the introduction to strengthen the contextual basis of their study: Dual effects of Caragana korshinskii introduction on herbaceous vegetation in Chinese desert areas: short-term degradation and long-term recovery.
Author Response
Comment 1: "The manuscript has undergone substantial revision, and the technical issues raised in the first review have been well addressed. The overall quality has improved significantly. However, the reference framework remains somewhat limited. It is recommended that the authors consider incorporating the following recent and relevant works into the introduction to strengthen the contextual basis of their study: Dual effects of Caragana korshinskii introduction on herbaceous vegetation in Chinese desert areas: short-term degradation and long-term recovery."
Response 1: The authors have discussed this extensively since the first round reviewers suggested using it. We reviewed the paper and though we find some very interesting aspects, there are some problems incorporating it into our study. First, the China study was conducted in a desert (arid) environment while we are in a temperate climate. There are some real and important differences in macropore conditions between our study area and those in China. Also, we are trying to solve this problem at the source rather than addressing how to mitigate excessive nutrients once they have been applied. We will certainly consider this for future publications and appreciate the suggestion by the reviewer.
