Application of Porous Concrete Infiltration Techniques to Street Stormwater Inlets That Simultaneously Mitigate against Non-Point Heavy Metal Pollution and Stormwater Runoff Reduction in Urban Areas: Catchment-Scale Evaluation of the Potential of Discrete and Small-Scale Techniques

Round 1

Reviewer 1 Report (Previous Reviewer 2)

see comments in attached file

Comments for author File: Comments.pdf

needs editing by a native English speaker 

Author Response

Revision Note

 

Shigeki HARADA

 

General

 

1. Regarding the “missing tables” that both reviewers mentioned, I knew that the PDF template file sent to the reviewers did not match the Word template file; the PDF file sent to the reviewers from the editorial office did not include Tables 1 to 3. I could not use the template because of time constraints and then submitted the manuscript as plain text, figures, and table files. The editorial office kindly attached the text and the figures and tables to the template, but presumably did not attach the tables when the file was converted to a PDF file, i.e., the files that the reviewers checked. Thus, the omission of Tables 1 to 3 was accidental and unintentional, which is a pity. The newly revised manuscript now includes the necessary tables and figures.

 

2. In the previous manuscript, the author considered placing porous concrete only at the bottom of the stormwater inlets. However, in the revised manuscript, the author performed estimates using Infoworks ICM (Innovyze) and assumed that the bottoms and the sides of the stormwater inlets are permeable. These analyses include 3D exfiltration from the stormwater inlets and then compare the magnitude of 3D and 1D exfiltration rates based on the theories and techniques published previously. On the other hand, the indoor leachate experiments using the experimental porous concrete column focused on 1D analyses. These 1D and 3D analyses are key to the current study.

 

3. The author did not intend to analyze the characteristics of the first flush pollutants, even though first flush runoff characteristics are quite important in non-point analyses. The author focused on the “begging of the rainfall” because the capacity of the author’s monitoring devise corresponds to runoff captured during the initial 1.5 mm rainfall. Another reason why the author paid attention to the behavior of the stormwater for the first 1.5 mm of rainfall is because, in Sendai, daily rainfall events are typically less than 2 mm. The author therefore added histograms of the daily rainfall volume in Sendai during the 1985-1990 and 2015-2019 periods to examine whether climate change caused any changes in rainfall patterns. In the new manuscript, the author underlined the need for further examination of first flush effects to evaluate the effects of porous concrete infiltration.

 

4. The author stressed that the purpose of the computation using the Infoworks ICM was to conduct sensitivity tests of water behavior within the networks by changing parameters such as the 3D exfiltration coefficient and not to obtain a detained description of water behavior. Naturally, the author attempted to discuss whether or not the values for the parameters mentioned above are realistic, based on literature reviews.

 

 

Reviewer A

 

Comment A1:  This is a much-improved paper compared to V1…but there is still significant room for improvement.

 

⇒　Thank you for the constructive feedback.

 

Comment A2: The aims in the Introduction could be reduced to

• Heavy metal concentrations in urban road runoff
• The adsorption of heavy metals by porous concrete
• The amount of runoff that can be treated in stormwater pits fitted with porous concrete filters

 

⇒　These points have been corrected as suggested.

 

Comment A3: Section 1.2….Definition of non point sources can be significantly reduced. Treatment process to treat non point sources could be expanded…focus on natural adsorption & deposition processes

 

⇒　These points have been corrected as suggested.

 

Comment A4:  Section 2.1…..sampling method could be reduced…but retain Figs 1,3 &4 &6

 

⇒　These points have been addressed as suggested.

 

Comment A5: Appears only soluble heavy metals were measured…no mention of the amount of heavy metals adsorbed onto sediment

 

⇒　Thank you for this comment. Please see Table 2.

 

Comment A6: Section 2.1…..Table 1 is not included in the pdf I downloaded….a major omission

 

⇒　Please see the first point in GENERAL above.

 

Comment A7: Figure 7 adds little to the paper…suggest its deletion

 

⇒　This figure was deleted as suggested.

 

Comment A8: Section 2.2….without Table 1 the text is hard to interpret…but suggest that concentrations from other studies also be added to the Table

 

⇒　 Please see the first point in the GENERAL section above. The addition of concentrations from other studies to Table 1 was thought not to be suitable considering the structure of Table 1.

 

 

Comment A9:  Section 4.1….report saturated Hydraulic Conductivity of the porous concrete column in mm/hr….same units as used later in the paper. Suggest porous concrete be referred to as an adsorption filter medium rather than an infiltration medium

⇒　The unit was corrected. The porous concrete column was used for the adsorption experiments but is also applicable as an infiltration medium. The author added a schematic diagram showing the water behavior at the stormwater inlets when porous concrete is used for the bottom and sides of the inlets in Section 4.2.

 

Comment A10:　Section 4.2 should be relocated later in the text

 

⇒　Because of the schematic diagram mentioned above, Section 4.2 is located where it is now.

 

 

Comment A11：Section 5…..more information should be provided in this section

• Volume of water applied & the volume of leachate collected
• Mixture & concentrations of heavy metals in the infiltrating water

3    Comparison of these concentrations with those measured in the road runoff ( ie Table 1)

4    mg/cm3 of heavy metals adsorbed for each infiltration treatment

 

⇒　The volume of water applied in “1” is shown in the text. However, the volume of the leachate in “1” could not be shown, because there were too many trials (5-12 runs for each leachate experiment with replicates). However, the ranges of the volume of the leachate are provided as general information about the whole experiments.

⇒　Also, “4” could not be done because there were too many trials  (5-12 runs for each leachate experiment with replicates).　

⇒　 Point 2  was addressed in Table 2. Point 3 was addressed in the text.

 

Comment A12:　Section 6…the phrase settlement of porous concrete boards is confusing…do you mean placement of porous concrete boards? However the analysis of contributing catchment area per stormwater inlet is quite informative, as is the area of concrete filter boards as a fraction of catchment area ( ie 0.02 -0.03%)

 

⇒　“Settlement” was replaced by “placement”.

⇒     As mentioned in Section 4.2, not only the bottom, but the wall could be permeable. Assuming a water level of 10 cm, the area of the porous concrete would be 0.04%. Please also see Figure 10 and the text in Section 6.

 

 

Comment A13: Section 7….this section would benefit by a definition sketch showing the floor & walls of the stormwater pit, the native soil, the placement of the porous concrete board, and the stormwater drain that transports runoff that does NOT infiltrate the native soil

 

⇒     Please see Figure 10.

 

 

The following comments A14, A15, A16 and A22 are each related strongly, so, the author shows the response as total of these four comments, again, at below the comment A22, separately from the response to each comment shown below the corresponding comment.

 

Comment A14: I am having a great deal of difficulty accepting that 3D infiltration (Q) is >= 100 greater than the vertical infiltration rate ( Ksat = 36mm/hr ?) . In pre wet soil occurring at the bottom of the pit , infiltration will be dominated by gravity not capillarity gradients. Hence the possible maximum infiltrations - via the pit floor & wall areas…will be 5 fold assuming all the infiltrating areas have equal fluxes . In reality the gradient through the walls will be less than unity ( ie from gravity) and if the walls of the pit are lined with conventional concrete, then the opportunity for lateral infiltration will be even less …..hence the 3D /1D factor will be less than 5 fold .

 

⇒   First of all, the vertical infiltration rate shown in the comment A14 as 36 mm/hour was modified to 100 mm/hour, citing [36].

⇒　The author assumed that the 3D/1D factor (“the 3D to 1D conversion coefficient” in the text) to be 10-20. Please see the text in the section 7.

 

Comment A15: Figure 13 is schematic of 3D infiltration from a bore hole used to measured saturated soil hydraulic conductivity . The shape of the wetting front depends strongly on the geometry of the hole and the antecedent water content of the soil. To purse the 3D-1D ratio further I suggest presentation of a more detailed analysis of the soil physics papers quoted in the text… especially Reynolds, Elrick & Clothier 1985. A rather useful paper on 3D exfiltration from stormwater trenches is given in the appendix to this report.

 

⇒　The 3D/1D ratio as 100 was obtained when the author gave the real size of the street inlets at Fukumuro Catchment (1.8m in diameter in average) into the Figure 2 of  Herath and Mushiake (1994) .

⇒    The author could not obtain the manuscript for “Reynolds, Elrick & Clothier 1985” because of time constraints (the abstract was read). The examination based on the literature should be done in near future.

 

 

Comment A16:　Section 8….putting to one side the correctness of the 3D/1D infiltration ratio this section needs to more clearly explain the assumed pathways of stormwater　exfiltration ….ie via the soil and via the connected stormwater drain. The assumption that ALL soil infiltration passes through the porous concrete needs to be made clearer. Similarly I assume the water that exits the stormwater drain is not affected by the porous concrete ?

 

 

⇒     Please see Figure 10.

 

Comment A22:REFERENCE

Blazejewski et al (2018) Comparison of infiltration models with regard to design of rectangular infiltration trenches .. Hydrological Sciences Journal 63 1707-1716

 

 

⇒　the author cited the literature shown above and compared with the other estimation methods of 3D to 1D conversion coefficients. Please see the text in the section 7.

 

 

Comment A17: Figures 14 & 15 show the fraction of a 3mm and 5mm runoff event that passes through the porous concrete in a stormwater pit before infiltrating into the soil. It suggests that 40 % does not get filtered & hence passes through the stormwater drain effectively untreated. If this is correct, then more explanatory text is needed. Incidentally ,Fig 14 shows 140% of the runoff is filtered by the porous concrete in pit # 761…..a physical impossibility !

 

⇒    As to the proportion of water pass through the stormwater drain untreated, please see the text in the section 8.

 

Comment A18: Section 9…the efficacy of treating only the first flush of runoff ( ie 3 to 5mm) needs a more detailed discussion. This would benefit from a chemograph or similar showing the variation in concentration of heavy metals through a runoff event eg concentration vs time or cumulative runoff. Alternatively, the EMC ( mg/L) of various runoff events could be calculated with/without the first 3 to 5 mm of runoff. Literature data would be OK if no site-specific experimental data is available. See attached exemplar graphic ( from a published paper!)



 

 

⇒    Please note that the author did not measure EMCs. Regarding the first flush issue, please see Response 3 in the GENERAL section.

 

Comment A19: Section 9 also estimates the amount of infiltration ( 2400 mm) that can pass through a porous concrete board before its Zn adsorption capacity is exhausted…..it’s not clear to me how this relates to the amount of road runoff. Assuming an average of 60% of the first 3 to 5mm of road runoff passes though the porous concrete , how does this 2400mm relate to the number of storm events ( > 3mm), and hence how much total runoff from the road catchment (mm) coincides with this number of events ? This information will give an idea of the time interval required to trigger the replacement of a concrete filter board.

 

⇒   Citing Harada and Komuro (2010), it was assumed that 41 years' worth of stormwater could be filtered by the porous concrete.

 

Comment A20: Section 10 adds nothing of significance to the main objectives of the

paper…..suggest it is deleted.

 

⇒    This text has been deleted as suggested.

 

Comment A21: The paper is missing a Conclusions section…..a major omission

 

⇒    A Conclusion has been inserted as suggested.

 

Comment A21:Much of the English expression is very idiosyncratic…suggest a final edit by a native　English speaker

 

⇒    The paper has been proofread by a native English speaker.

 

Revision Note

 

Shigeki HARADA

 

General

 

1. Regarding the “missing tables” that both reviewers mentioned, I knew that the PDF template file sent to the reviewers did not match the Word template file; the PDF file sent to the reviewers from the editorial office did not include Tables 1 to 3. I could not use the template because of time constraints and then submitted the manuscript as plain text, figures, and table files. The editorial office kindly attached the text and the figures and tables to the template, but presumably did not attach the tables when the file was converted to a PDF file, i.e., the files that the reviewers checked. Thus, the omission of Tables 1 to 3 was accidental and unintentional, which is a pity. The newly revised manuscript now includes the necessary tables and figures.

 

2. In the previous manuscript, the author considered placing porous concrete only at the bottom of the stormwater inlets. However, in the revised manuscript, the author performed estimates using Infoworks ICM (Innovyze) and assumed that the bottoms and the sides of the stormwater inlets are permeable. These analyses include 3D exfiltration from the stormwater inlets and then compare the magnitude of 3D and 1D exfiltration rates based on the theories and techniques published previously. On the other hand, the indoor leachate experiments using the experimental porous concrete column focused on 1D analyses. These 1D and 3D analyses are key to the current study.

 

3. The author did not intend to analyze the characteristics of the first flush pollutants, even though first flush runoff characteristics are quite important in non-point analyses. The author focused on the “begging of the rainfall” because the capacity of the author’s monitoring devise corresponds to runoff captured during the initial 1.5 mm rainfall. Another reason why the author paid attention to the behavior of the stormwater for the first 1.5 mm of rainfall is because, in Sendai, daily rainfall events are typically less than 2 mm. The author therefore added histograms of the daily rainfall volume in Sendai during the 1985-1990 and 2015-2019 periods to examine whether climate change caused any changes in rainfall patterns. In the new manuscript, the author underlined the need for further examination of first flush effects to evaluate the effects of porous concrete infiltration.

 

4. The author stressed that the purpose of the computation using the Infoworks ICM was to conduct sensitivity tests of water behavior within the networks by changing parameters such as the 3D exfiltration coefficient and not to obtain a detained description of water behavior. Naturally, the author attempted to discuss whether or not the values for the parameters mentioned above are realistic, based on literature reviews.

 

 

Reviewer A

 

Comment A1:  This is a much-improved paper compared to V1…but there is still significant room for improvement.

 

⇒　Thank you for the constructive feedback.

 

Comment A2: The aims in the Introduction could be reduced to

• Heavy metal concentrations in urban road runoff
• The adsorption of heavy metals by porous concrete
• The amount of runoff that can be treated in stormwater pits fitted with porous concrete filters

 

⇒　These points have been corrected as suggested.

 

Comment A3: Section 1.2….Definition of non point sources can be significantly reduced. Treatment process to treat non point sources could be expanded…focus on natural adsorption & deposition processes

 

⇒　These points have been corrected as suggested.

 

Comment A4:  Section 2.1…..sampling method could be reduced…but retain Figs 1,3 &4 &6

 

⇒　These points have been addressed as suggested.

 

Comment A5: Appears only soluble heavy metals were measured…no mention of the amount of heavy metals adsorbed onto sediment

 

⇒　Thank you for this comment. Please see Table 2.

 

Comment A6: Section 2.1…..Table 1 is not included in the pdf I downloaded….a major omission

 

⇒　Please see the first point in GENERAL above.

 

Comment A7: Figure 7 adds little to the paper…suggest its deletion

 

⇒　This figure was deleted as suggested.

 

Comment A8: Section 2.2….without Table 1 the text is hard to interpret…but suggest that concentrations from other studies also be added to the Table

 

⇒　 Please see the first point in the GENERAL section above. The addition of concentrations from other studies to Table 1 was thought not to be suitable considering the structure of Table 1.

 

 

Comment A9:  Section 4.1….report saturated Hydraulic Conductivity of the porous concrete column in mm/hr….same units as used later in the paper. Suggest porous concrete be referred to as an adsorption filter medium rather than an infiltration medium

⇒　The unit was corrected. The porous concrete column was used for the adsorption experiments but is also applicable as an infiltration medium. The author added a schematic diagram showing the water behavior at the stormwater inlets when porous concrete is used for the bottom and sides of the inlets in Section 4.2.

 

Comment A10:　Section 4.2 should be relocated later in the text

 

⇒　Because of the schematic diagram mentioned above, Section 4.2 is located where it is now.

 

 

Comment A11：Section 5…..more information should be provided in this section

• Volume of water applied & the volume of leachate collected
• Mixture & concentrations of heavy metals in the infiltrating water

3    Comparison of these concentrations with those measured in the road runoff ( ie Table 1)

4    mg/cm3 of heavy metals adsorbed for each infiltration treatment

 

⇒　The volume of water applied in “1” is shown in the text. However, the volume of the leachate in “1” could not be shown, because there were too many trials (5-12 runs for each leachate experiment with replicates). However, the ranges of the volume of the leachate are provided as general information about the whole experiments.

⇒　Also, “4” could not be done because there were too many trials  (5-12 runs for each leachate experiment with replicates).　

⇒　 Point 2  was addressed in Table 2. Point 3 was addressed in the text.

 

Comment A12:　Section 6…the phrase settlement of porous concrete boards is confusing…do you mean placement of porous concrete boards? However the analysis of contributing catchment area per stormwater inlet is quite informative, as is the area of concrete filter boards as a fraction of catchment area ( ie 0.02 -0.03%)

 

⇒　“Settlement” was replaced by “placement”.

⇒     As mentioned in Section 4.2, not only the bottom, but the wall could be permeable. Assuming a water level of 10 cm, the area of the porous concrete would be 0.04%. Please also see Figure 10 and the text in Section 6.

 

 

Comment A13: Section 7….this section would benefit by a definition sketch showing the floor & walls of the stormwater pit, the native soil, the placement of the porous concrete board, and the stormwater drain that transports runoff that does NOT infiltrate the native soil

 

⇒     Please see Figure 10.

 

 

The following comments A14, A15, A16 and A22 are each related strongly, so, the author shows the response as total of these four comments, again, at below the comment A22, separately from the response to each comment shown below the corresponding comment.

 

Comment A14: I am having a great deal of difficulty accepting that 3D infiltration (Q) is >= 100 greater than the vertical infiltration rate ( Ksat = 36mm/hr ?) . In pre wet soil occurring at the bottom of the pit , infiltration will be dominated by gravity not capillarity gradients. Hence the possible maximum infiltrations - via the pit floor & wall areas…will be 5 fold assuming all the infiltrating areas have equal fluxes . In reality the gradient through the walls will be less than unity ( ie from gravity) and if the walls of the pit are lined with conventional concrete, then the opportunity for lateral infiltration will be even less …..hence the 3D /1D factor will be less than 5 fold .

 

⇒   First of all, the vertical infiltration rate shown in the comment A14 as 36 mm/hour was modified to 100 mm/hour, citing [36].

⇒　The author assumed that the 3D/1D factor (“the 3D to 1D conversion coefficient” in the text) to be 10-20. Please see the text in the section 7.

 

Comment A15: Figure 13 is schematic of 3D infiltration from a bore hole used to measured saturated soil hydraulic conductivity . The shape of the wetting front depends strongly on the geometry of the hole and the antecedent water content of the soil. To purse the 3D-1D ratio further I suggest presentation of a more detailed analysis of the soil physics papers quoted in the text… especially Reynolds, Elrick & Clothier 1985. A rather useful paper on 3D exfiltration from stormwater trenches is given in the appendix to this report.

 

⇒　The 3D/1D ratio as 100 was obtained when the author gave the real size of the street inlets at Fukumuro Catchment (1.8m in diameter in average) into the Figure 2 of  Herath and Mushiake (1994) .

⇒    The author could not obtain the manuscript for “Reynolds, Elrick & Clothier 1985” because of time constraints (the abstract was read). The examination based on the literature should be done in near future.

 

 

Comment A16:　Section 8….putting to one side the correctness of the 3D/1D infiltration ratio this section needs to more clearly explain the assumed pathways of stormwater　exfiltration ….ie via the soil and via the connected stormwater drain. The assumption that ALL soil infiltration passes through the porous concrete needs to be made clearer. Similarly I assume the water that exits the stormwater drain is not affected by the porous concrete ?

 

 

⇒     Please see Figure 10.

 

Comment A22:REFERENCE

Blazejewski et al (2018) Comparison of infiltration models with regard to design of rectangular infiltration trenches .. Hydrological Sciences Journal 63 1707-1716

 

 

⇒　the author cited the literature shown above and compared with the other estimation methods of 3D to 1D conversion coefficients. Please see the text in the section 7.

 

 

Comment A17: Figures 14 & 15 show the fraction of a 3mm and 5mm runoff event that passes through the porous concrete in a stormwater pit before infiltrating into the soil. It suggests that 40 % does not get filtered & hence passes through the stormwater drain effectively untreated. If this is correct, then more explanatory text is needed. Incidentally ,Fig 14 shows 140% of the runoff is filtered by the porous concrete in pit # 761…..a physical impossibility !

 

⇒    As to the proportion of water pass through the stormwater drain untreated, please see the text in the section 8.

 

Comment A18: Section 9…the efficacy of treating only the first flush of runoff ( ie 3 to 5mm) needs a more detailed discussion. This would benefit from a chemograph or similar showing the variation in concentration of heavy metals through a runoff event eg concentration vs time or cumulative runoff. Alternatively, the EMC ( mg/L) of various runoff events could be calculated with/without the first 3 to 5 mm of runoff. Literature data would be OK if no site-specific experimental data is available. See attached exemplar graphic ( from a published paper!)



 

 

⇒    Please note that the author did not measure EMCs. Regarding the first flush issue, please see Response 3 in the GENERAL section.

 

Comment A19: Section 9 also estimates the amount of infiltration ( 2400 mm) that can pass through a porous concrete board before its Zn adsorption capacity is exhausted…..it’s not clear to me how this relates to the amount of road runoff. Assuming an average of 60% of the first 3 to 5mm of road runoff passes though the porous concrete , how does this 2400mm relate to the number of storm events ( > 3mm), and hence how much total runoff from the road catchment (mm) coincides with this number of events ? This information will give an idea of the time interval required to trigger the replacement of a concrete filter board.

 

⇒   Citing Harada and Komuro (2010), it was assumed that 41 years' worth of stormwater could be filtered by the porous concrete.

 

Comment A20: Section 10 adds nothing of significance to the main objectives of the

paper…..suggest it is deleted.

 

⇒    This text has been deleted as suggested.

 

Comment A21: The paper is missing a Conclusions section…..a major omission

 

⇒    A Conclusion has been inserted as suggested.

 

Comment A21:Much of the English expression is very idiosyncratic…suggest a final edit by a native　English speaker

 

⇒    The paper has been proofread by a native English speaker.

 

 

 

 

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

Paper needs significant revision. English is very poor.

Tables are mentioned that are not in the text.

There are figures that are not referred to in the text. Many of these are not needed to support the research.

The authors refer to papers that have information, but do not give any summaries of that information for the readers. Readers are not going to go look up these other papers, so give a summary.

There are places in the text where items are bullet pointed, rather than discussed in detail and in the context of the paper. For example, page 2 1st paragraph.

On page 3, why were precip events of 1-2 mm used? This is very low rainfall.

Paper needs significant revision. English is very poor.

 

Author Response

Revision Note

 

Shigeki HARADA

 

General

 

1. Regarding the “missing tables” that both reviewers mentioned, I knew that the PDF template file sent to the reviewers did not match the Word template file; the PDF file sent to the reviewers from the editorial office did not include Tables 1 to 3. I could not use the template because of time constraints and then submitted the manuscript as plain text, figures, and table files. The editorial office kindly attached the text and the figures and tables to the template, but presumably did not attach the tables when the file was converted to a PDF file, i.e., the files that the reviewers checked. Thus, the omission of Tables 1 to 3 was accidental and unintentional, which is a pity. The newly revised manuscript now includes the necessary tables and figures.

 

2. In the previous manuscript, the author considered placing porous concrete only at the bottom of the stormwater inlets. However, in the revised manuscript, the author performed estimates using Infoworks ICM (Innovyze) and assumed that the bottoms and the sides of the stormwater inlets are permeable. These analyses include 3D exfiltration from the stormwater inlets and then compare the magnitude of 3D and 1D exfiltration rates based on the theories and techniques published previously. On the other hand, the indoor leachate experiments using the experimental porous concrete column focused on 1D analyses. These 1D and 3D analyses are key to the current study.

 

3. The author did not intend to analyze the characteristics of the first flush pollutants, even though first flush runoff characteristics are quite important in non-point analyses. The author focused on the “begging of the rainfall” because the capacity of the author’s monitoring devise corresponds to runoff captured during the initial 1.5 mm rainfall. Another reason why the author paid attention to the behavior of the stormwater for the first 1.5 mm of rainfall is because, in Sendai, daily rainfall events are typically less than 2 mm. The author therefore added histograms of the daily rainfall volume in Sendai during the 1985-1990 and 2015-2019 periods to examine whether climate change caused any changes in rainfall patterns. In the new manuscript, the author underlined the need for further examination of first flush effects to evaluate the effects of porous concrete infiltration.

 

4. The author stressed that the purpose of the computation using the Infoworks ICM was to conduct sensitivity tests of water behavior within the networks by changing parameters such as the 3D exfiltration coefficient and not to obtain a detained description of water behavior. Naturally, the author attempted to discuss whether or not the values for the parameters mentioned above are realistic, based on literature reviews.

 

 

Reviewer B

 

Comment B1: Paper needs significant revision. English is very poor.

 

⇒　The revised version has been proofread by a native English speaker.

 

Comment B2: Tables are mentioned that are not in the text.

 

⇒　Please see the first point in the GENERAL section for an explanation.

 

Comment B3: There are figures that are not referred to in the text. Many of these are not needed to support the research.

 

⇒　Some figures were deleted and the remaining figures are referred to in the text.

 

Comment B4: The authors refer to papers that have information, but do not give any summaries of that information for the readers. Readers are not going to go look up these other papers, so give a summary.

 

⇒　The author has attempted to provide summaries of these papers where possible.

 

Comments B5: There are places in the text where items are bullet pointed, rather than discussed in detail and in the context of the paper. For example, page 2 1st paragraph.

 

⇒　The author focused on the following three points. The author used bullet pointed items to make clear the points.

- Heavy metal concentrations in urban road runoff

- The adsorption of heavy metals by porous concrete

- The amount of runoff that can be treated in stormwater pits fitted with porous concrete filters

 

 

Comments B6: On page 3, why were precip events of 1-2 mm used? This is very low rainfall.

 

⇒　Please see the third point in the GENERAL section for an explanation.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report (Previous Reviewer 2)

The author is to be congratulated on accepting most of my previous comments. It reads much better than Draft #2 

NIL

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 study presents an introduction on the application of infiltration techniques for the reduction of pollution in Japan. The study presented appears to be a mere introduction to a larger study and lacks results of sufficient substance to be published. It is limited to describing what is to be studied, a sort of extension of the methodology to be used, but without presenting any results.  In my opinion, it would be necessary to extend the study to make it relevant for publication.

The abstract must be completely changed, summarizing the research carried out and its main conclusions. At the moment, it is completely generic and seems more like an introduction to the topic rather than an abstract.

The number of self-citations is excessive. Only the authors' own work directly related to the research should be cited.12 self-citations are excessive. In addition, the article should improve the state of the art with references to other authors from other research groups and of other nationalities. At present, the bibliography is almost entirely domestic.

The FORMAT of the document requires a thorough revision prior to publication; there are fonts and text formats that differ from those standardized by the journal.

The language also needs to be proofread, as there are some sentences that are difficult to understand, and the overall style is not scientific. Also, it is recommended to restructure the chapters and subchapters. There are too many and with strange titles.

In section 3.3, is there any standard (normative) that supports this methodology? In addition, it would be recommended to separate “methodology” and “results”

Some minor remarks.

·        In line 67, why “the authors”?

·        In line 95, please put the link in the bibliography

Author Response

Please see attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

see attached file

Comments for author File: Comments.pdf

Author Response

Please see attachment.

Author Response File: Author Response.docx