Quantitative Assessment of Impact of Climate Change and Human Activities on Streamflow Changes Using an Improved Three-Parameter Monthly Water Balance Model

Round 1

Reviewer 1 Report

This study is on Quantitative assessment of impact of climate change and human activities on streamflow changes using an improved three parameter monthly water balance.

The authors compared three different hydrological models in Zhejiang Province using the APHRODITE rainfall dataset as input. The authors found that CM model performance is good as compared to others. Additionally, the impact of climate change is more dominant than human activities in different river basins. The work is interesting and the manuscript is well organized. However, some issues have to be considered before the manuscript is ready for publishing

Add one table for calibration and validation periods for each station because data periods are different for each station or add one column in Table 4.

In table2 provide the description of parameters used for model calibration.

In figure 6 (e-f) low flows results are simulated well, why?

In table 6 please explain the results, some values are positive and a few are negative, positive and negative sign explanation.

In results and discussion part, the discussion is very weak, the authors do not cite a single paper in this part. Please add some discussion related to results.

Page1; line 37: please use one helping verb

This symbol ∀? is repeatedly used in equations, why?

Page10; line 315: replace NES with “NSE”

Please use similar legend colors in Taylor diagram as shown in figure 4b

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript 1840063 “Quantitative assessment of impact of climate change and human activities on streamflow changes using an improved three parameter monthly water balance model” developed a three-parameter water balance model to assess the separation impact of climate change and human activities by comparing with different inputs, models and separation methods.

The methods used in this study were basically sound, and the manuscript was well organized and written. However, there are several issues should be addressed before final decision was made.

1)      Abstract. More information should be complete. For example, the results of comparing the modeling of different models as well as the separation results.

2)      Trying to distinct the physical-based hydrological model from the empirical model, also the distribution hydrological model from the lumped mode (or conceptual model) in introduction.

3)      In terms of climate change impact on streamflow, there are general two ways. The directly way is the change in precipitation and ETp directly impact the streamflow, which is the major way and obvious. The indirectly way is the climate change firstly impact on the underlying surface such as vegetation dynamics, then influencing the interception, relationship of rainfall-runoff, and ETa, which ultimately would impact on the streamflow. The models that the authors used seem did not consider the indirect impact.

4)      The Budyko-based separation method used in this study did not consider the underlying surface change. The parameter w in equation 23, 24 was also a variable varied along with time in terms of climate change. Therefore, the impact of climate change on w should also be considered in the equation 22.

5)      Why did the authors comparing the APHRODITE precipitation products with the observation precipitation at the watershed scale? I think the results of the comparison largely depend on the spatial interpolation method (Thiessen polygon), which is not reasonable to compare the product accuracy itself. I recommend the authors compare the products with the observation at the meteorological station scale. By the way the “meteorological” in the legend of Figure 2 was wrong.

6)      The manuscript completely lack of a substantial discussion about the findings.

 

More details of above issues can be reference to:

Zhang, S., Yang, H., Yang, D., et al., 2016. Quantifying the effect of vegetation change on the regional water balance within the Budyko framework. Geophysical Research Letters 43, 1140-1148.

Ning, T., Li, Z., Liu, W., 2016. Separating the impacts of climate change and land surface alteration on runoff reduction in the Jing River catchment of China. CATENA 147, 80-86.

Yang, L., Feng, Q., Yin, Z., et al., 2017. Identifying separate impacts of climate and land use/cover change on hydrological processes in upper stream of Heihe River, northwest China. Hydrol. Process. 31, 1100-1112.

Jiang, C., Xiong, L., Wang, D., et al., 2015. Separating the impacts of climate change and human activities on runoff using the Budyko-type equations with time-varying parameters. J. Hydrol. 522, 326-338.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

As the authors addressed the reviewers' comments successfully the manuscript can be accepted for publication.

Reviewer 2 Report

The authors have addressed my comments appropriately.