A Systematic Review of the Scientific Literature on Pollutant Removal from Stormwater Runoff from Vacant Urban Lands
Round 1
Reviewer 1 Report
The article deals with the important topic of pollutants contained in stormwater from vacant urban lands and methods for their removal. The article is original and well-written. It is based on the current literature review. I highly value the work. I have got only a few comments which are listed below:
1. The abstract is a bit too long. The part from "The priority in reviewing..." to "...in order to remove contaminants from urban runoff" may be considered for removal. Also, the aim of the work is emphasized twice - at the beginning ("The project aims to...") and at the end (The aims of this paper are to...") of the abstract. It is enough for the aim to appear at the beginning.
2. In the Introduction section, the second paragraph discusses two factors influencing the pollutant load. It would also be worth mentioning the impact of time between rainfall on the pollutant load. After a long time without rainfall, the concentration of pollutants in the first flush is higher because rain washes the pollutants off the ground. I propose to add a comment on this topic.
Author Response
We appreciate the reviewer's constructive and useful comments, which help us improve the manuscript and supplementary material quality. Please see the revised manuscript.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The article contains useful information but there are recent review papers on the effectiveness of stormwater management practices with regards to reducing contaminant loads and concentrations. Thus, I do not believe the paper adds much information to the stormwater community in this regards. The relationship of VUL and contaminants is important and interesting.
Also, the paper needs to be revised and corrected for grammar, sentence structure, etc. I was not sure of the intended meaning of many sentences and/or paragraphs.
Here are some other detailed comments:
Line 8. What is an ecological intervention? Using this term leads to more questions. Please revise to make the intended meaning more clear.
Line 9. Remove the word “the”
Line 12. Were the papers reviewed to see which type of VUL had a large number of pollutants only, or did you also investigate the type/kind of pollutants? If you did the latter, state that here.
Line 14. What size was considered, plan area (i.e., footprint), water quality volume, or something else?
Line 16. In addition to pollutant concentration, pollutant mass load is just as important and, in some cases, more important than concentration. Pollutant mass load can be reduced via infiltration even if the concentration does not change. Thus, pollutant mass load should be included.
Line 20. “..of on VUL..” grammar issue.
Line 21. What is a BMP. Acronyms should be defined before they are used. Also, it should be stormwater BMPs. A more common term now is stormwater control measure (SCM).
Line 23. When referring to metal, nutrient, and phosphorus removal, are you referring to the dissolved component or particulate component, or both. The distinction is very important. Also, phosphorus is considered a nutrient, so to say “..nutrients and phosphorus..” is redundant. And phosphorus should not be capitalized.
Line 25-26. I do not understand the sentence that begins “Medium with high hydraulic conductivity covering or media with low hydraulic conductivity…” In addition, is it medium or media? Be consistent.
Line 28. The sentence, as worded, makes it sound like wet ponds always have PAH removal rates of 99%. This is not true. It could be that they were found to have removal rates as high as 99%, though.
Line 31. What load? Volume of runoff or pollutant load? If it’s pollutant loading, this is why pollutant load is often more important than pollutant concentration.
Line 41. Be objective. How long? Please at least give a time frame for reference.
Line 44. The phrase “and so on” is too vague. Many more common pollutants should be listed.
Line 45. Grammar issue.
Line 47. The climate change claim needs a reference.
Line 50. More than just rust belt cities will need additional action.
Line 77. The sentence that ends on this line needs a reference.
Line 84. Stormwater runoff does not implement on-site infiltration measures. Stormwater managers or engineers do.
Line 110. Again, what size are you referring to? Area, water quality volume, or something else?
Line 140. The sentence beginning “I have expanded my search…” sounds more like a note to yourself than a statement in a technical journal.
Line 273. Stormwater doesn’t contain many sources of heavy metals, it contains many heavy metals.
Line 275. “Large amounts of heavy metals…” means high mass loads. But do you mean high concentrations? Please be specific and clarify if it is high concentrations, high mass loads, or both.
Line 281. Other two types of what?
Line 351-352. These are not two runoff pollutants, they are two kinds (or categories) of runoff pollutants that include many, many pollutants.
Line 402-403. LID and BMPs have a lot of overlap. Some would say they are the same thing. To say they are two methods of stormwater management is not quite accurate.
Line 404. “Good” is subjective. Be objective. Do you mean to achieve or meet regulations?
Line 428. The sentence reads that urban runoff is adsorbed to soil organic matter, which is not true. I think you mean a portion of the dissolved metals.
Line 430. Only the solid or particulate fraction of metals is removed through interception, and then only a fraction of it will/can be.
Line 434. Again, it depends if the metals are particulate or dissolved.
Line 467. The sub-section heading does not make sense to me.
Line 469. Not all TSS is captured by filters. It depends on many factors and small TSS will pass through most filters.
Line 481. General comment on this section: For nitrogen removal to occur there are two possible processes. One is nitrogen capture via activated carbon or some other mechanism/substance. The other is nitrification/denitrification, which is a two-step biological process that requires an anoxic zone and a carbon source. Nitrogen can change form, but it is not truly removed unless one of these two processes occur.
Line 493. This sentence belongs in the previous section.
General comment: If nitrogen is retained via uptake by plants, it will ultimately be released with the plant dies and decomposes. Thus, the nitrogen is retained, but not removed.
Line 590. Table 4 does not appear to be related to PAHs but the text and table caption say it is.
Line 605. I don’t see Figure 2 anywhere.
Line 608. The period should be located inside the quotation mark (e.g., Tool.”)
Line 608. Are you referring to a table or a figure? If a table, what table?
General comment. There are other stormwater management cost tools available such as the iDST tool at GA Tech (https://smartech.gatech.edu/handle/1853/62873), the CLASIC tool (https://clasic.erams.com/docs/), The USEPA National Stormwater Calculator https://www.epa.gov/water-research/national-stormwater-calculator). There is also a report on costs and effectiveness at: https://ascelibrary.org/doi/10.1061/%28ASCE%290733-9496%282007%29133%3A3%28218%29
Author Response
We appreciate the reviewer's constructive and useful comments, which help us improve the manuscript and supplementary material quality. Please see the revised manuscript.
Author Response File: Author Response.pdf
Reviewer 3 Report
For detailed comments, please refer to the attached pdf.
Overall, some changes need to be done particularly on rephrasing, completing some sentences. Formatting issues throughout the article paper also need to be revised.
Comments for author File: Comments.pdf
Author Response
We appreciate the reviewer's constructive and useful comments, which help us improve the manuscript and supplementary material quality. Please see the revised manuscript.
Author Response File: Author Response.pdf
Reviewer 4 Report
1． The title of the manuscript is about the rainwater runoff pollution from vacant urban lands, but many of the references cited in the part of 3.5 are not aimed at vacant urban lands.
2． There were many writing errors of subscript, such as in Line 288,471,472,506,509.
3． The content in the part 3.3 describes the source of pollutants, not the pollution load described in the title.
4． It is suggested to replace the sequence of parts 3.3 and 3.4.
5． It is suggested to supplement the literature analysis about SS removal.
6． Parts 3.4 and 3.5 are suggested to be simplified and can be expressed in the form of list
Author Response
We appreciate the reviewer's constructive and useful comments, which help us improve the manuscript and supplementary material quality. Please see the revised manuscript.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
The current paper is much improved and all comments/concerns have been addressed.
Only one minor point of clarification needs to be addressed. In my original review there was a question about the meaning of the term "ecological intervention" and that term was changed to "nature-based interventions." Even though the name has been changed, the original question remains: What is the meaning of "nature-based" interventions. Does this mean stormwater control measures or is it some broader definition that includes stormwater control measures, etc. If the meaning is stormwater control measures, there's no need to introduce a new term. It just raising a question (or worse, creates confusion). If it does not mean stormwater control measures, then please define/explain what it means and how it relates to the focus of the manuscript.
Thanks to the author for their contribution to the field.
Author Response
Thank you very much for your affirmation and approval of my article. We appreciate the reviewer's constructive and valuable comments, which help us improve the manuscript and supplementary material quality. Please see the revised manuscript (New Version for Abstract).
Author Response File: Author Response.pdf
Reviewer 4 Report
The revised manuscript was improved greatly, and my concern questions were well responded.
Author Response
Thank you very much for your affirmation and approval of my article. We appreciate the reviewer's constructive and valuable comments, which help us improve the manuscript and supplementary material quality. Please see the revised manuscript.
