气象水文复合驱动下桉树人工林区水库水体突发性泛黑及演变机理

Ecological environment issue of Eucalyptus plantation is a key scientific topic with global concern, especially the deforestation and water safety problem. The physical characteristics of blackwater in Eucalyptus forest reservoirs and the effects on water quality of drinking water resources have not been identified thoroughly. Meanwhile, the driving mechanism of sudden blackening in reservoirs and the generation and dissipation process of hypoxic blackwater events are still unknown. They have become key technical problems expected to be solved urgently in the regulation and control of water quality. Therefore, to distinguish characterization and causes of sudden blackening, ascertain long-term generation and dissipation process of hypoxic blackwater events and clarify short-term blackening under the drive of meteorology and hydrology in the reservoir, field observation in situ, laboratory experiment and mathematical model are combined in this research. Meanwhile, transport mechanism of temperature, dissolved oxygen, dissolved organic matter in a multi interface such as atmosphere and water interface, water and sediment interface, oxidation and reduction interface will be investigated; A multi-factor coupling simulation technology coupling meteorological, hydrology and sediment transport is expected to reenact and calculate the evolution of generation, accumulation, trigger, dissipation of blackwater. In addition, the ways and consequences of the Eucalyptus Plantation effects on reservoir blackening will be evaluated and optimal adaptive regulation measures are proposed to protect the water quality of reservoirs with sudden blackening problem. The projected findings of this study are supposed to have significant technical recommendations for the scientific cultivation of Eucalyptus plantations and protection of drinking water safety.

桉树人工林区生态环境问题是全球性关注的重大科学问题，林区水库大面积突发性泛黑引发的水量水质安全问题更是关注焦点。甄别桉树人工林区水库黑水物质特性及其对生活饮用水水源地水质的影响，阐明气象水文复合驱动下水库突发性泛黑及演变机理，已成为泛黑水库水质适应性调控和饮用水安全保障亟待解决的关键技术难题。本项目将现场观测、室内实验和数学模拟相结合，拟研究水库突发性泛黑现象表征和诱因，探索气象和水文复合驱动下水库泛黑短期骤变机理和黑水长期生消演变过程，解析水库温度、溶解氧、有机物质等多因子在气-水界面、水-土界面及氧化-还原界面间的运移机制；开发气象-水文-底质复合驱动下水库黑水运移模拟技术，反演与预测水库黑水孕育-累积-触发-消亡全过程，明晰桉树人工林影响水库泛黑的途径与贡献，提出泛黑水库水质保护的最优化适应性调控措施。预期研究成果对指导我国南方地区桉树人工林科学种植及水库环境保护具有重要意义。

我国南方地区大量引种速生桉树，给当地社会经济带来巨大贡献同时，也产生了新的生态环境问题，特别是桉树人工林区水库冬季突发性泛黑引发的生态环境安全问题更是关注焦点，然而其泛黑机制仍不清楚。本研究以广西南宁两座典型水库（天雹和百合水库）为例，从三个界面（大气-水体、水体-底泥、氧化-还原界面）开展气象水文复合驱动下桉树人工林区水库水体突发性泛黑及演变机理研究。具体为：（1）利用高频立体野外观测系统，开展水库大气-水体-底泥多维度跨界面复合参数运移观测，开展控温控湿条件下桉树和库区其他优势树种叶、茎、根浸泡实验，鉴别水库黑水物质成分和理化性质，明确黑水是否存在有毒有害物质及对饮用水源安全的影响程度；（2）利用典型泛黑水库在泛黑前、中、后大气-水体-底泥复合参数立体观测数据以及不同区域的水文和水动力观测数据，研究气象和水文条件骤变下库区水体色度、水质及水动力的短期异常特征，进一步揭示水库黑水孕育-累积-触发-消亡全过程循环机制；（3）采用EFDC模型对水库水动力-水质进行三维数值模拟，分析溶解氧垂向浓度分布的演化成因，重点探讨水库热分层结构对溶解氧垂向分层演化过程的影响。以上研究成果可为桉树人工林区水库水污染防治和饮用水安全保障提供理论基础和技术支撑。