流域洪灾风险传递规律研究

Research on the Flood Risk Transfer Mechanisms within Watersheds

以珠江流域为例,提出一套基于“风险因子识别-风险评估-风险传递规律解析”的研究体系。首先,利用可拓模型对珠江流域洪灾风险进行评估,然后运用马尔科夫模型研究风险时间变化规律,最后应用空间马尔科夫链模型探究风险空间传递效应。结果表明:①高风险区主要位于下游的珠江三角洲,而低风险区主要位于上游的南北盘江;②流域洪灾风险等级保持不变的概率较大,发生变化时多为相邻等级渐变,由于上游水资源区汇流会对下游水资源区产生影响,洪灾风险具有积聚效应;③流域内洪灾风险上游对下游的正向传递多于负向传递,下游风险经累积有所增高;④高风险区对其周围水资源区风险传递类型为增强型传递,而低风险区为衰减型传递。

This paper presents a new risk research methodology by integrating impact factor identification,risk evaluation,and transfer characteristics analysis within a framework applied to the Pearl River basin for case study.Firstly,this paper uses extension analysis model to evaluate the flood risks in the Pearl River Basin.Then,the Markov model is used to study the temporal variation of risk.Finally,the spatial Markov chain model is used to explore the effect of risk transfer.Results show that:①The flood risk in the Pearl River Delta is high while lower risks occur in the North Panjiang and South Panjiang River basins.②The probability that flood risks keeping unchanged is rather high,the variations in the probability gradually occur between the two neighboring levels.Subject to the impact of the confluence of upstream water resources areas,the flood risks exhibit the accumulation effect.③The flood risk transfer from the upstream to downstream is more positive than negative,and the downstream risk has increased;④The area with high risk shows enhanced transfer mechanism while the area with low risk shows decreased transfer mechanism.