Estimation of Mining and Landfilling Activities with Associated Overburden through Satellite Data: Germany 2000–2010

Round 1

Reviewer 1 Report

This application of topographic change data as an alternate/ comparative method of assessing the amount of resource extraction and landfilling within a country is an interesting idea and I believe the results will be of interest to a broader audience. While I appreciate that the article is written at a level that does not require technical details regarding the creation and analysis of these DEM products, the complete lack of detail regarding these datasets -- and more importantly the error they potentially carry with them-- glosses over the potential errors that exist in the results of this study and does a disservice to the reader. 

Specific critiques: 

1) The focus of references cited in section 1.2 Remote sensing applications in Industrial Ecology is primarily upon drainage network creation and analysis, which is a niche field of DEM-based environmental modeling and terrain analysis. This section seems to be broadly addressing the use of DEMs in terrain analysis for varied environmental modeling applications. Suggest including more varied references 

2) Additional detail and explanation is needed in the methods section (2.2 - Bottom-up method...) to explain how CORINE and Non-Forest Map were used to exclude forested areas from analysis. This exclusion also warrants some mention in the discussion section - is it not possible that back-filled areas could revert to a forested environment over the course of the study time period (a decade?). This is the case in the mountaintop-removal/ valley fill mining in Appalachia (United States) -- albeit the forest that regrows is very different than the pre-mining forest. However, this means that currently forested areas must be included in topographic and mining-related change detection (because it could have been mined in previous years and regrown trees). This may be less relevant in your study area, but at the very least additional detail should be added to the methods section to describe this exclusion. 

3) Additional detail is necessary in the methods/ explanation of the equations. Specifically for the "volume in year t at place i" ... etc.  How were these factors calculated? Using what datasets? Be specific so that your study could be repeated by someone else in a different area of interest. 

4) Grammar - line 169: In order to compare 'these' results... 

5) Figures - include/ improve legends for figure 4 and 5 

6) Discussion section: include additional discussion about the impact of DEM error on the estimates of resource extraction/ landfilling.  DEM error is a huge complicating factor in volumetric calculation and most applications do some sort of accuracy analysis that puts error bars on their estimates of volumetric change. At the very least, some mention of the amount of error potentially included in each of these DEMs is necessary. This possibly warrants additional information/ references in background section - suggest Wechsler and Kroll (2006), Deng (2007), Mukherjee and others (2013). 7) This third cause of difference is significant, and warrants its own paragraph. The current phrasing of it glosses over the host of challenges associated with DEM-based topographic change and volumetric change estimation - DEMs from the 2000s are available for very specific time periods, created from different datasets via different methods (synthetic aperture radar vs. photogrammetric/ stereo extraction), and thus have differing levels of error associated with them. This is absolutely a limiting factor of the analysis performed here, but does not necessarily mean that the results from DEM-based analysis aren't useful as a comparison or check against a top-down resource extraction estimation -- which perhaps is the a key point in this section. Suggest additional elaboration of each of these 3 factors to make each a distinct point.

7) review verb tense throughout article

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

ln 69: The issues presented in this section (1.2) are not remote sensing based methods. DEM might be generated using stereography or InSAR, but not only. Please, change the name of the section or refer to remote sensing in generation of elevation data.

ln 72: DEM is not a map - it's a model. It might be used to a map creation, but DEM itself is not a visualisation of itself, but a model - hidden on a disk drive.

ln 174: Table 2: "Word's first..." - should be "World's first..." Also, I suggest adding another column for DEM h accuracy. It might be different, due to different way of data collection.

ln 176: Fig. 1: Please, specify what "select" below Aster and SRTM means? and how is it processed. Also, what is "minus"?

ln 181: erroneous reference to the source - number of such problems later in the text.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Edits made to the manuscript have improved the quality of its content. In particular, the content that has been added to several sections has improved the background information necessary to understand the analysis. 

Reviewer 2 Report

The corrections mad by Authors are satysfying

All the best!