涉水工程影响下的寨岗河流域山洪灾害多情景模拟研究

Multi-scenario simulation study on flash floods in the Zhaigang River Basin under the influence of hydraulic engineering

摘要

【目的】山洪灾害是全球最为常见且破坏力极强的自然灾害之一，随着气候变化的持续加剧，山洪暴发的频率及强度显著增加，使得山洪灾害模拟研究在防灾减灾和风险评估等领域的重要性日益凸显。然而，单一的水文或水动力模型在山洪模拟时通常存在局限，且常常忽略了山区涉水工程如桥梁、堰坝等对洪水演进的叠加影响，导致山洪的易发性及其潜在危害被低估。为提高寨岗河流域山洪灾害模拟的准确性及可靠性。【方法】通过构建水文水动力耦合模型(CNFF-IFMS)开展寨岗河流域山洪灾害模拟研究，运用耦合模型进一步量化分析防御河段上的三座桥梁(B1、B2、B3)及一座堰坝(W1)在多情景重现期(2 a、5 a、10 a、20 a、50 a及100 a)下的山洪响应机制，并开展了洪水风险分析与评估。【结果】结果显示：桥堰建成后，各重现期下的断面水位相较于无桥堰时均有所上升，加剧了漫堤风险，并诱发了回水效应。根据回水效应的强度，其顺序由强至弱依次为W1、B1、B3和B2;各重现期下的断面流速相较于无桥堰时均有所降低，但普遍加大了对工程周边二维区域的冲刷；各重现期下的淹没面积和区间水深范围相较于无桥堰时均有所增加，总淹没面积从2~100 a一遇洪水增加了4.732 km²,与无桥堰相比增加了0.046 km²。【结论】结果表明：水文水动力耦合模型较好地反映了流域降雨径流响应及其在山区沟道中的洪水传播机制，实现了山区洪水在时间和空间上的动态演进。同时，桥堰等涉水工程的重要性不容忽视，在一定程度上放大了山洪灾害的影响后果，亟需将其纳入流域山洪模拟研究范畴以减小模拟结果的不确定性。研究成果可为寨岗河及其他类似山区流域的防灾减灾提供技术支撑与参考。

Abstract

[Objective] Flash floods are one of the most common and destructive natural disasters globally. With the continuous intensification of climate change, both the frequency and intensity of flash floods have notably increased. Consequently, the significance of flash flood simulation research in the fields of disaster prevention, mitigation, and risk assessment has become increasingly prominent. However, the use of a single hydrological or hydrodynamic model often has limitations in flash floods simulation and frequently overlooks the cumulative effects of hydraulic structures, such as bridges and weirs, on flood progression in mountainous areas. This oversight can lead to the underestimation of flash floods susceptibility and potential risks. [Methods] A coupled hydrological and hydrodynamic model(CNFF-IFMS) was developed to improve the accuracy and reliability of flash flood simulations in the Zhaigang River Basin. The coupled model was further employed to quantitatively analyze the flash floods response mechanisms of three bridges(i.e., B1, B2 and B3) and one weir(W1) located in the river defense sections of the basin under multiple return period(i.e., 2 a, 5 a, 10 a, 20 a, 50 a and 100 a). Additionally, flood risk analysis and assessment for the basin were conducted. [Results] After the construction of the bridge and weir, the water levels at the cross-sections during various return periods have all increased compared to the situation without the bridge and weir, exacerbating the risk of overtopping and inducing backwater effects. According to the intensity of the backwater effects, they are ranked from strongest to weakest as W1, B1, B3, and B2. The velocities at the cross-sections during various return periods have all decreased compared to the situation without the bridge and weir, but they have generally increased the scouring of the two-dimensional area around the project. The flooded area and the range of water depth during various return periods have all increased compared to the situation without the bridge and weir. The total flooded area increased by 4.732 km² from the 2-year to the 100-year flood event, an increase of 0.046 km² compared to the situation without the bridge and weir. [Conclusion] The result indicated that the coupled hydrological and hydrodynamic model effectively reflected the basin rainfall-runoff response and its flood propagation mechanism in mountain gullies, realizing the dynamic evolution of mountain floods in time and space. Moreover, the importance of hydraulic structures such as bridges and weirs cannot be ignored, as they exacerbate the impacts of flash flood disasters to some extent. It is crucial to incorporate these structures into basin flash floods simulation studies to reduce uncertainty in the simulation result. The research can provide technical support and reference for disaster prevention and reduction in the Zhaigang River and other similar mountainous watersheds.

关键词

山洪灾害 / 水文水动力耦合 / 涉水工程 / 洪水 / 风险评估 / 气候变化 / 降水 / 数值模拟

Key words

flash floods / coupled hydrology and hydrodynamics / hydraulic structures / flood / risk assessment / climate change / precipitation / numerical simulation

基金资助

国家自然科学基金项目(42271095)

广东省水利科技创新项目(2025-08)