基于水功能区控制单元的流域突发性水污染事件风险评价区划及其应用

Risk Assessment Zoning and Application of Watershed Sudden Water Pollution Events Based on Water Function Area Control Unit

以水功能区控制单元为基础,结合子流域划分工作单元。采用压力-状态-响应(PSR)环境分析模型构建环境风险源危险性指标体系,进行流域环境风险源识别及其危险性等级评价。增加"环境风险源下游特征"指标以考虑风险源流经下游重要性不同的水功能区(工作单元)对其本身危险性等级的影响。结合指标数据、标准和权重,采用模糊综合评价法计算风险源的危险性(以及工作单元的脆弱性等级)。参考河流一维污染物衰减模型,建立工作单元危险性等级评价方法。工作单元危险性等级由两部分叠加构成,即本单元风险源的危险性等级和上游风险源通过河流对下游工作单元危险性的影响。结合工作单元的危险性和脆弱性等级,通过风险矩阵评价工作单元的风险等级。在此基础上,在同一水功能区控制单元,合并风险相同的工作单元,实现流域风险评价区划。将上述方法应用在滦河流域中上游。研究表明,滦河流域中上游共55个风险区,其中高风险区I有3个,较高风险区II有15个,较低风险区Ⅲ有14个,低风险区IV有23个,说明滦河流域中上游整体风险性偏低;并对不同等级风险区提出相应的管理方案。

Based on the water function area control unit, and combined with sub watershed, we divided the research units. The risk index system of environmental risk sources was constructed by using the pressure state response （PSR） environment analysis model to identify the environmental risk sources and evaluate the risk level. The downstream characteristics of the environmental risk source is added to take into account the impact of the water function areas （work units） on the risk level of the risk sources through the downstream importance of the water. Combined with index data, standards and weights, fuzzy comprehensive evaluation method is used to calculate the risk of risk sources （and the vulnerability level of work units）. Referring to the one-dimensional pollutant convection diffusion model of rivers, a risk assessment method for working units is established. The risk level of the unit is composed of two parts, that is, the risk level of the source of this unit and the impact of the upstream risk source on the risk of the downstream work unit. Combining risk and vulnerability level of work unit, risk level of work unit is evaluated through risk matrix. On the basis of this, the watershed risk assessment zoning is implemented in the same water function area control unit and the working unit with the same risk. The above method is applied to the upper and middle reaches of the Luanhe River Basin. The study shows that there are 55 risk zones in the upper and middle reaches of the Luanhe River Basin, of which there are 3 I in high risk areas, 15 in higher risk areas, 14 in the lower risk area and 23 in the low risk area, and 23 in the low risk area, indicating that the overall risk of the upper and middle upper reaches of the Luanhe River Basin is low, and the management schemes for different grade risk areas are put forward.