| 17 Nov 2025
Climate Impacts on Water Resources in a High Mountain Catchment: Application of the Open-Source Modeling Workflow MATILDA in the Northern Tian Shan
Abstract. Applied glacio-hydrological modeling is crucial for the integrated water management strategies needed to effectively mitigate climate change impacts on freshwater resources fed by high mountain areas. We demonstrate the application of MATILDA-Online, an open-source toolkit for modeling glacier evolution and water resources in glacierized catchments. We showcase it's capabilities in data-scarce environments on a catchment in the Tian Shan Mountains in Kyrgyzstan, and outline a four-step multi-objective calibration strategy that integrates glacier surface mass balance, snow water equivalent, and discharge observations. Projections indicate severe glacier mass loss by 2100, significant reductions in runoff, and a shift toward earlier peak flow driven by snowmelt. The main sources of uncertainty in the catchment water balance are biases in precipitation data and inconsistencies in glacier mass balance datasets, highlighting the importance of adequate monitoring. Despite limitations in the model's representation of spatial variability and dynamic processes, MATILDA provides easy access to sophisticated modeling and can be a valuable tool for bridging the gap between advanced glacio-hydrological science and practical water resource management.
Dear authors,
The manuscript presents a test case of the open-source toolkit MATILDA-online, which simulates glacier evolution and water resources in the Kyzylsuu Valley in the Tian Shan Mountains. The main focus of the manuscript is a four-step calibration procedure and the validation of the model results. The authors hope to provide an open-access toolkit to support data-driven water resource management and learning for local practitioners and other non-academic stakeholders in in-situ data-scarce regions.
I praise the authors' efforts in providing open-access resources to improve the capacity of local stakeholders in the Global South. However, the manuscript, in its current stage, requires a substantial revision. The biggest issue amongst the others is that Part I of the double publication is still under review in another journal. The authors did not introduce the model components in this manuscript at all, sometimes not even expanding abbreviations. Thus, I can’t fully assess the quality of the model chain and its ability to provide accurate information to the stakeholders, as mentioned by the authors as the aim of the model in the Introduction.
A few more major concerns are as follows:
Thus, I don’t think this manuscript, in its current form, is suitable for publication even after a major revision because we don't know if its 'sister' paper will be accepted at all. I see the value in the study, but perhaps the author could put more effort into the storytelling and the accessibility of the language to non-academic experts, if you really want MATILDA to fulfill its purpose. I suggest that the authors revise the manuscript carefully and resubmit it after the first manuscript is accepted.
Below are some of my more specific comments:
Section 3 Methods
There is no description of the toolkit and its model components. Some abbreviations are not even expanded. I understand that there is a 'sister' manuscript that provides additional details. However, at least some key elements should be included here so that readers don’t need to read another article to grasp what MATILDA does. In addition, the sister manuscript is still under review in another journal. It means that as a reviewer, I need to review two manuscripts to ensure the accuracy of my judgments.
Section 4 Results
The structure of this section is very confusing. ERA5-Land is also presented here, even though the authors did not produce the forcing data. Sec. 4.2 basically only summarizes Table 2. What is the message here? A lot of abbreviations are used, which made it very hard to follow what the authors wanted to convey, especially for non-academic readers, whom they addressed in their introduction. Could we consider starting the sections or paragraphs with a sentence that describes their content or key messages?
Section 5 Discussions
Shouldn’t Sect 5.2.3 be in Sect. 4?
And it will also be helpful to have some discussion on how MALTILDA is a better tool for the local stakeholders than the other glacio-hydrological tools, as it seems to be the “innovation” presented in the Introduction. From what I can see on the MATILDA website, it appears to be a model chain that combines a PDD model, a glacier volume/Area rescaling routine, and the openly assessable HBV model, combined with a significant calibration component.
Perhaps it is discussed in the first paper. However, without reviewing the first paper, I would not know if the model chain is really novel. In particular, from what I have read in the current discussion, MATILDA faces the same challenges as other glacial-hydrological models, i.e., forcing data and the modeling workflow.
Section 6 Conclusions
Overall, I am not convinced that ‘MATILDA offers a solution by supporting, educating, and empowering water management stakeholders in regions affected by climate change.’ It is not supported by what was written in the manuscript.
Figures
From Figure 2, we can see that the interannual variation of the simulated SMB does not match that of the reference study and the observations. In the conclusion, the author wrote, “The temperature index model with the modified Δh routine can provide reasonable long-term estimates of glacial contributions to runoff, including stabilizing effects at higher elevations (Schuster et al., 2025c). However, this setup fails to reproduce observed inter-annual changes and neglects important glaciological factors such as glacier dynamics and debris cover”. Does this really show the robustness of the model chain? How important are glacier dynamics and debris cover compared to the ability of the model to reproduce the observations in the time period you are looking at, i.e., 20 years?