水文变异对汉江中下游水华暴发的驱动机制与风险评估

With the construction and operation of the South-to-North Water Transfer Project, tremendous changes have taken place in hydrological regime in the middle and lower reaches of the Hanjiang River in recent years, furtherly aggravating the problems of water environment deterioration and algal bloom disaster. Therefore, a theoretical study on the driving mechanism and risk assessment of algal bloom outbreak in the middle and lower reaches of Hanjiang River considering hydrological alteration is carried out in order to meet the needs of the river basin ecological protection and integrated water resources management. First, the formation mechanism of algal bloom and the requirements of environmental factors in the middle and lower reaches of Hanjiang River are revealed by application of the field stereoscopic monitoring system and algal growth control experiments, and the key hydrodynamic triggering conditions and parameter thresholds are identified. Then, the hydrological alteration diagnosis system is adopted to explore the alteration characteristics of the upper and lower reaches' hydrological sequences of the study area, and the response relationship between hydrological alteration rule and hydrodynamic process is established. Third, the numerical simulation technology of algal bloom early-warning under mutual driving among hydrological, hydrodynamic and water quality indexes is developed to invert and forecast the whole process of algal bloom's inoculation, outbreak and extinction in the middle and lower reaches of the Hanjiang River. At last, the quantitative assessment method of river algal bloom risk based on the fusion of hydrological probability density function and stochastic simulation technique is proposed to explore the driving effect of hydrological alteration on the increase of algal bloom outbreak risk, and an emergency regulation scheme of environmental flow is put forward which is most beneficial to algal bloom control. The expected results are of great significance to guide the prevention and control of the algal bloom and the sustainable utilization of water resources in the middle and lower reaches of the Hanjiang River.

近年来，随着南水北调等工程的建设运行，汉江中下游水文情势发生了极大改变，进一步加剧了当地的水环境恶化与水华灾害问题。为此，面向流域水生态保护和水资源综合管理需求，开展水文变异对汉江中下游水华暴发驱动机制与风险评估理论研究。运用野外立体监测系统和藻类生长影响控制实验，揭示汉江中下游水华形成机理和环境要素需求，识别水华形成的关键水动力触发条件和参数阈值；采用水文变异诊断系统，探究研究区上下游水文序列的突变特征，阐明水文变异与水动力过程的响应关系；开发水文-水动力-水质复合驱动下水华预警数值模拟技术，反演与预测汉江中下游水华孕育-暴发-消亡全过程；提出融合水文概率密度函数和随机模拟技术的河流水华风险定量评估方法，研究水文变异对水华暴发风险增加的驱动效果，提出最有利于水华消减的环境流量应急调控方案。预期成果对指导汉江中下游水华防控和水资源可持续开发利用具有重要意义。

针对水利工程建设引发河流水华加剧的现实问题，开展水文变异对汉江中下游水华暴发驱动机制与风险评估理论研究。采用水文变异诊断系统，探究研究区典型断面水文序列的突变特征，阐明水文变异与水动力过程的响应关系；借助遥感技术和数值模拟技术，探究了汉江中下游水华形成机理和环境要素需求，识别水华形成的关键水动力触发条件和参数阈值；开发水文-水动力-水质因子复合驱动下水华预警数值模拟技术，反演与预测汉江中下游水华孕育-暴发-消亡全过程；提出融合水文概率密度函数和随机模拟技术的河流水华风险定量评估方法，研究水文变异对水华暴发风险增加的驱动效果，提出适用于汉江下游水生态系统保护的生态流量方案。研究成果对指导汉江中下游水华防控和水资源可持续开发利用具有重要意义。.基于本项目研究成果，累计发表学术论文26篇，其中，SCI收录13篇，EI收录5篇；获得发明专利1项，软件注册权1项；在科学出版社出版了《闸控河流水环境模拟与调控理论研究》专著，并参编了《中国水科学研究进展报告2019-2020》。部分研究成果“闸控河流水质转化机理级关键调控技术与应用”获河南省科技进步三等奖。承办了水系统前沿问题研讨会、黄河流域生态保护和高质量发展高层科技论坛“水资源战略”分论坛等学术会议，指导博士后出站1人，毕业硕士研究生8人。