**5. Conclusions**

The current study was carried out to evaluate the reservoir construction's impact on LR discharge using double-mass curve analysis, estimating the CV for the closely related hydro-meteorological phenomena of LRB and identifying a trend on the hydrometeorological behavior of the LRB using the well-known MK-S test. We found that:


2016 was the outcome of the two dams built over the LR. The Zhikong hydropower plant and the Pangduo power plant—which began operations in 2006 and 2013, respectively—have been influencing the LR discharge and causing a substantial variation in the LR discharge.

3. The MK-S test revealed a non-significant increase in the rainfall and a subsequent increase in LR discharge for the time 1956–1999. However, for the time span of 2000–2016, the rainfall in LRB experienced a non-significant decrease, whereas the LR discharge significantly decreased with an amplified magnitude that could be wellattributed to the reservoir functioning in the LRB. The temperature in the LRB was found to significantly decrease for the time spans of 1956–1999 and 2000–2016. The increase in temperature was more in the latter time span and potentially affected the snowmelt, evapotranspiration, and (ultimately) the discharge of the LR on a seasonal scale.

While predicting the LR discharge from 2017 to 2025, SWAT-ARIMA coupling revealed:


**Author Contributions:** This research is carried out in collaboration with all authors. Conceptualization, M.Y. and T.H.; methodology, M.Y.; software, M.Y. and S.A.H.; validation, M.Y. and S.A.H.; formal analysis, M.Y.; data curation, T.H.; writing—original draft preparation, M.Y.; writing—review and editing, T.H.; supervision, T.H.; project administration, T.H.; funding acquisition, T.H. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study has been supported by the National Natural Science Foundation of China (Grant No. 91647204), and Wuhan Center of China Geological Survey (Grant No. 2020028; 2020023, YRSW-2020-359).

**Acknowledgments:** We thank three anonymous reviewers and editors for constructive suggestions and comments.

**Conflicts of Interest:** The authors declare no conflict of interest.
