Multiscale Detection and Assessment of Vegetation Eco-Environmental Restoration following Ecological Water Compensation in the Lower Reaches of the Tarim River, China
Round 1
Reviewer 1 Report
This study analyzed, with remotely sensed images, the spatiotemporal responses of vegetation and groundwater to the commitment of the Ecological Water Compensation project in an arid region of China. The results confirmed the effectiveness of the water discharge to the riparian vegetation where precipitation is extremely short for plant growth. The study illustrated that the influence of the water delivery might reach to as far as 10 km from the river via groundwater infiltration, though there were one year lag between the water discharge and the plant flourishing. The manuscript was well written and I have only some minor comments for the revision.
1. It may be friendlier for reading to label the vertical axis of Figure 6 with the site names instead of the letters.
2. Line 317: what’s the DC value?
3. Without sufficient figure captions, the two panel of Figure 11 is not discriminable. In the main text (Line 395-398), the correlations between the water table and the volume of water discharge are stated with correlation coefficients, while as in Figure 11 they are expressed with R^2. It’ll be better to show them in the same way. Same questions referring to Figure 12 and the main text (Line 417-426).
4. Line 522-523: 4 meters or -4 meters?
5. Line218-219: “By trial and error, we finally determined that the NDVIveg value of the study area was 0.86, while the NDVIsoil value was 0.11”. NDVIveg stands for pixels of pure vegetation. I wonder why there are pixels in Figure 14 with NDVI values larger than 0.86.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Thank you for the opportunity to read this manuscript. I think the authors have done a great job executing this study. It was very interesting to see the use of remote sensing data to investigate the effectiveness of a large-scale environmental water delivery program. There are lots of similar programs around the world and the method used here could be applicable in an array of locations.
My only general suggestion for how the study could be improved is to more thoroughly cover the potential influence of rainfall on the vegetation condition. I know that the authors state in line 507, “Because precipitation is generally less than 100 mm in the hyperarid region of the Tarim River basin, the survival and regeneration of natural vegetation highly depends on renewable groundwater instead of precipitation in this area.” However, because it seems that the volume of water delivered is dependent to some extent on how much rainfall has fallen in the region. Therefore, there is scope for the two variables (water delivery and rainfall) to have a mutually beneficial effect on vegetation condition. It might be possible to use the residuals of the relationship between ground water depth as a function of water delivery volume and plot these residuals against rainfall for the region. The results of this data summary would show how regularly periods of high rainfall coincided with lower than expected reductions in depth to the water table and vice versa. If these occurred regularly, it would be reasonable to conclude that the majority of the effect of change in water table depth was driven by water delivery volume. If the authors choose not to include an analysis similar to this one, the potential influence of rainfall at least needs to be discussed more comprehensively in the discussion.
Specific comments
L78 italicize euphratica
L129 Can you define the acronym TBAB in full? This is the first time it has been used in the body of the manuscript.
L293 Figure 5 I think the right panel would be more easily interpretable if the colour scheme had a different colour for significantly positive trend, significantly negative trend and no significant trend. At present, a reader has to look between the left and right panels to determine which areas with a significant trend are increasing and decreasing.
L314 It is not clear what you mean when you say, “vegetation activities were increasing”
L403 Figure 11 it is not stated what the two panels of this figure depict. Is one the current year data and one for the lagged-year (although the R2 value does not match the value reported in the text for the lagged relationship.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
