Identifying hydrological drought in reservoirs is a significant challenge in water resource management. In South Korea, drought in reservoirs has historically been identified and managed through measuring storage amount. However, drought identification in accordance with storage amount has a possibility of failure to secure enough time for proper drought countermeasures. This study aims to suggest supplementary criteria for quantitatively identifying drought based on storage amount and water balance—specifically to allow more time to implement countermeasures against drought on the Andong dam. The standardized balanced index (SBI) was newly suggested to consider dry/wet conditions of dam, and the Standardized storage volume index (SSVI) was employed to consider storage amount. The proper duration of each index was estimated to be 4-month for SBI and 9-month for SSVI. A bivariate drought identification diagram using both index and copula function was derived and applied to the Andong dam. The diagram identified drought to occur 3.7 months earlier than the existing criteria which used storage amount to identify drought, and showed applicability for supplementary criteria.

识别水库中的水文干旱是水资源管理中的重大挑战。在韩国，历史上已经通过测量存储量来识别和管理水库中的干旱。然而，根据存储量进行干旱识别可能无法确保足够的时间来采取适当的干旱对策。这项研究旨在为基于储水量和水平衡定量确定干旱的补充标准提出建议-具体而言，是为了让更多的时间在安东大坝上实施针对干旱的对策。新建议使用标准化平衡指数（SBI）考虑大坝的干/湿状况，并采用标准化储水量指数（SSVI）考虑储水量。对于SBI，每个指数的适当期限估计为4个月，对于SSVI，每个指数的适当期限为9个月。导出了同时使用指数和copula函数的双变量干旱识别图并将其应用于安东大坝。该图确定干旱发生时间比现有标准早了3.7个月，后者使用存储量来确定干旱，并显示了补充标准的适用性。