School of Water Conservancy Engineering, Zhengzhou University, Zhengzhou 450001, China.
School of Water Conservancy Engineering, Zhengzhou University, Zhengzhou 450001, China; School of Software, Zhengzhou University, Zhengzhou 450002, China.
Sci Total Environ. 2021 May 10;768:145312. doi: 10.1016/j.scitotenv.2021.145312. Epub 2021 Jan 21.
Extreme floods caused by dike or dam breaks have led to substantial damage to various types of vegetation, including forests, orchards, grass, and crops. Many factors affect the impacts of extreme floods on plants, e.g., flood parameters, plant characteristics and natural factors. However, these factors have never been systematically analyzed or considered when evaluating the impacts of extreme floods on plants. Firstly, we summarized the main influencing factors and simplified them into six categories: temperature, geomorphic change, plant age, flood velocity, ratio of the flood depth to the plant height, and ratio of the flood duration to the plant waterlogging tolerance time. Secondly, we proposed the two indices of unit risk biomass (URB) and total risk biomass (TRB) to represent the impacts of floods on plants regionally and over the entire inundated area, respectively. In addition, the calculation methods of URB and TRB considering plant biomass and the comprehensive influence coefficient (I) were put forward. To calculate I, we considered the six influencing factors with different weights according to their importance and varying conditions. The flood parameters and geomorphic changes caused by a simulated dam-break flood of Luhun Reservoir in China were then calculated. Furthermore, we divided a year into six time periods according to the species and growth characteristics of the plants in the inundated area. Then we evaluated the impacts of the dam-break flood on the plants during each period. The results showed that: (a) the URB varied with space in the inundated area; (b) because of the large inundation area of crops, the TRB was far greater than that of forests and orchards and affected the TRB of the whole inundated area; and (c) both the URB and TRB changed with time with the changes in crop species, crop parameters and temperature.
堤坝决堤引发的极端洪水对各种类型的植被造成了严重破坏，包括森林、果园、草地和农作物。许多因素影响极端洪水对植物的影响，例如洪水参数、植物特征和自然因素。然而，在评估极端洪水对植物的影响时，这些因素从未被系统地分析或考虑过。首先，我们总结了主要的影响因素，并将其简化为六个类别：温度、地貌变化、植物年龄、洪水速度、洪水深度与植物高度之比以及洪水持续时间与植物耐淹时间之比。其次，我们提出了单位风险生物量（URB）和总风险生物量（TRB）这两个指标，分别代表洪水对植物的区域性和整个淹没区的影响。此外，还提出了考虑植物生物量和综合影响系数（I）的 URB 和 TRB 的计算方法。为了计算 I，我们根据其重要性和变化条件，考虑了六个影响因素的不同权重。然后计算了中国陆浑水库模拟大坝溃决洪水的洪水参数和地貌变化。此外，我们根据淹没区植物的物种和生长特征，将一年分为六个时间段。然后，我们评估了每个时期大坝溃决洪水对植物的影响。结果表明：（a）淹没区 URB 随空间变化；（b）由于农作物的大面积淹没，TRB 远大于森林和果园的 TRB，并影响整个淹没区的 TRB；（c）URB 和 TRB 随时间变化，作物种类、作物参数和温度的变化而变化。
