Abstract

This paper discusses the results from investigating the factors that led to the formation of a catastrophic flood in June 2019 on the Iya river in the city of Tulun, Irkutsk oblast, as well as from calculating and assessing the characteristics of these floods. An analysis of the meteorological environments of flood formation is performed by using the ICON global weather forecast model. The trends in hydrometeorological characteristics for the period 1966–2019 are analyzed. The study revealed an increase in the June precipitation amount by 36–61% (31–46 mm), and negative trends in the maximum water discharges making up 24–37% from May to September. Using data on the water level and historical Q(H) curves, the maximum daily water discharge on June 29, 2019 was estimated at 6800 ± 700 m³/s. A schematization of the Iya river basin is carried out, the parameters are systematized and the distributed Hydrograph hydrological model is verified. For three subbasins within the Iya river basin, the median value of the Nash–Sutcliff criterion was 0.69 for the period 1970–1996. The flood characteristics are simulated and assessed using two sources of meteorological data. According to data from weather stations, the maximum daily discharge was 6570 m³s. This value falls within the range of estimates of observed values but its formation is delayed by 1 day. According to the simulation based on the ICON model data, the maximum 3-hour discharge reached 5260 m³/s, or at least 840 m³/s lower than the observed value; however, the simulated flood hydrograph coincides with observed one for the time intervals. The results of the study confirm a possibility for a short-term flood forecast using the method of deterministic hydrological modeling.

中文翻译：

---

伊亚河（Irkutsk Oblast）2019年夏季灾难性洪水的建模

摘要

本文讨论了调查导致伊尔库茨克州土伦市伊亚河于2019年6月形成灾难性洪水的因素以及计算和评估这些洪水的特征的结果。使用ICON全球天气预报模型对洪水形成的气象环境进行了分析。分析了1966-2019年期间水文气象特征的趋势。研究表明，6月降水量增加了36-61％（31-46毫米），最大排水量的负趋势从5月到9月占24-37％。使用水位数据和历史Q（H）曲线数据，2019年6月29日的每日最大排水量估计为6800±700 m ³/ s。对伊亚河流域进行了模式化，对参数进行了系统化，并验证了分布式水文水文模型。对于伊亚河流域内的三个子流域，1970年至1996年期间，纳什–萨克利夫准则的中值为0.69。使用两种气象数据源对洪水特征进行模拟和评估。根据气象站的数据，最大日排放量为6570 m ³ s。该值落在观测值的估计范围内，但其形成被延迟了1天。根据基于ICON模型数据的模拟，最大3小时排放量达到5260 m ³ / s，或至少840 m ³/ s低于观测值；但是，模拟洪水水位图在时间间隔内与观测到的一个一致。研究结果证实了使用确定性水文模拟方法进行短期洪水预报的可能性。