• Journal of Korea Water Resources Association
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• v.57 no.4
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• pp.237-248
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• 2024

Watershed runoff that is an important component of the hydrological processes has been significantly altered by climate variability and human activities in many watersheds around the world. It is important to investigate the impacts of climate variability and human activities on watershed runoff change for water resource management. In this study, using watershed runoff data for 109 middle-sized watersheds in Korea, the impacts of climate variability and human activities on watershed runoff change were quantitatively evaluated. Using the Pittitt test, the analysis period was divided into two sub-periods, and the impacts of climate variability and human activities on the watershed runoff change were quantified using the Budyko hypothesis-based climate elasticity method. The overall results indicated that the relative contribution of climate variability and human activities to the watershed runoff change varied by middle-sized watersheds, and the dominant factors on the watershed runoff change were identified for each watershed among climate variability and human activities. The results of this study enable us to predict the watershed runoff change considering climate variability and watershed development plans, which provides useful information for establishing a water resource management plan to reduce the risk of hydrological disasters such as drought or flood.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.146-146
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• 2018

Basin evapotranspiration is the result of water balance and energy balance, which is affected by climate and underlying surface characteristics, the process is complex, and spatial and temporal variability is large, the evapotranspiration estimation of river basin is an important but difficult problem in the field of hydrology, over the years, many scholars devoted to the basin actual evapotranspiration estimation and achieved excellent results. We discuss Budyko coupled water-energy balance theory and evaporation paradox, then use the Fu's equation to estimate actual evapotranspiration yearly in different areas with different dryness. The result shows that Fu's equation has high precision for estimating evapotranspiration yearly in our selected study area, and the estimation result has higher precision in the area with high dryness. Then, we propose an improved formula which can be used to estimate actual evapotranspiration monthly. Furthermore, we found that the parameter in the formula reflects general conditions of underlying surface and it is affected by several factors, at last, we tried to propose the calculation formula. The study indicates that Fu's equation provides a reliable method for evapotranspiration estimation in dry regions as well as semi-humid and semi-arid regions, which has great significance for forecasting river basin water resources and inquiring into ecological water requirement.