【摘要】 基于先进的Ad H水动力学计算模型,以美国内华达州塔基河迈卡伦研究域为例,从主槽-洪泛区系统的流场特性、不同河道形态下的跨界流量分布以及粒子在系统内运动传输规律三个方面,详尽地分析洪水过程下主槽与洪泛区之间的水力交互连通关系。研究结果表明,在洪峰流量期间,有接近60%的洪峰流量从洪泛区经过,约为主槽流量的1.52倍;主槽-洪泛区之间的跨界流量交换方向和量级受到河流形态和洪峰流量的共同影响;粒子示踪统计结果表明绝大数(>85%)粒子能够至少一次穿过河流边界,揭示出主槽和洪泛区之间存在较强的水体交换,此外,粒子运动轨迹和停留时间分布特点反映主槽-洪泛区系统水力交互关系具有较强的时空分异特性。更多还原

【Abstract】 Hydrological exchange between a river and its floodplain plays a critical role in maintaining river ecosystem. Herein, a state-of-art hydrodynamic model(Ad H) was applied in modeling flood events in the Truckee River at lower Mc Carran ranch in Nevada. The hydrologic connectivity between main channel and floodplains is examined in details through flow field characteristics, trans-boundary flux, and particle tracing analysis. Results reveal substantial spatial variations of main channel-floodplain flux exchanges in both magnitude and direction. During a flood peak, up to 60% of its total discharge flows into floodplain, or about 1.52 times as much as that in main channel. Trans-boundary flux can be affected by both the river morphology and discharge magnitude. Particle-tracing shows that a large majority of particles(>85%) passed over the boundaries for at least one time, revealing a strong flux exchange at the interface of main channel and floodplains during flood events. The particle trajectory and residence time distribution also reflected a spatial and temporal heterogeneity of hydraulic interactions in a main channel-floodplain system.更多还原