The Improved Reservoir Module of SWAT Model with a Dispatch Function and Its Application on Assessing the Impact of Climate Change and Human Activities on Runoff Change

Abstract

Climate change and human activities significantly impact the hydrological cycle, particularly in regions with numerous large-scale reservoirs. Recognizing the limitations of the reservoir module in the original SWAT model, this study presents an improved reservoir module based on a dispatch function to enhance runoff simulation. Its performance is validated by simulating daily runoff in the Jinsha River Basin, China. The scenario simulation approach is employed to quantitatively analyze the influences of climate change and human activities on runoff. And downscaled Global Climate Models (GCMs) are utilized to predict runoff for the next three decades. The results show that (1) the improved SWAT model outperforms the original model in runoff simulation; (2) during the test period, reservoir regulations caused a reduction of 26 m3/s in basin outlet runoff, while climate change led to an increase of 272 m3/s; and (3) future changes in basin outlet runoff over the next 30 years exhibit a high level of uncertainty, ranging from −5.6% to +11.0% compared to the base period. This study provides valuable insights into the hydrological impacts of climate change and human activities, highlighting the importance of incorporating an improved reservoir module in hydrological modeling for more accurate predictions and assessments.

Runoff response to multiple land‐use changes and climate perturbations

“…Farsi and Mahjouri (2019) utilized the DREAM algorithm to analyse the uncertainty in the parameters of two Jazim-based monthly water balance models, derived the posterior probability distribution function of the cycle parameters, and used the two monthly water balance models and the fixed-variation approach to compute the contribution of anthropogenic and climate change contribution to runoff variability. Sheng et al (2023) proposed an improved reservoir module based on the dispatch function, which improves watershed runoff simulation in combination with the SWAT model. Wang et al (2023) quantitatively evaluated the relative contributions of climate change, land use, and other human activities to runoff in the Fen River (FR) Basin using the double cumulative curve method, the SWAT model, and statistical analysis.…”