船行波与风生浪共同作用对浅水湖泊沉积物再悬浮及蓝藻水华影响机理研究

Internal nutrient release from sediment induced by turbulence is very difficult to be illustrated for the control of algal bloom in the large shallow lakes in China. The key point of it is to figure out the mechanism of driving forces for inducing the sediment resuspension. The cyanobacteria blooms in most of the Chinese eutrophic shallow lakes (e.g. Lake Taihu, Chaohu, Dianchi) exhibit the characteristics of floating, transportation, and spatial accumulation. All those processes are greatly impacted by the waves and currents in the lakes. At the same time, most of those lakes have the functionalities of navigation, tourism and fisheries. During the human activities, the ship generated waves would change the wave and current pattern in the lakes markedly, and then affect internal nutrient release from sediment and the spatial distribution of algal bloom. This study will take Lake Taihu as an example, and concentrate on studying the mechanism of sediment resuspension and algal bloom induced by combined ship and wind generated waves in large shallow lakes. The objectives are: to develop the in-lake monitoring stations and to obtain the continuous high-resolution vertical profiles of instant 3D velocity, wave parameters, suspended solids before and after ship navigation in the shallow lake, and then to figure out the hydrodynamic pattern , the process of sediment resuspension, and the spatial distribution pattern of algal bloom under the co-existing ship wave and wind wave; on the basis of mathematic analysis, to decouple the weight and contribution of impacts from ship wave and wind wave on the aquatic environment, to explore the response of internal nutrient release from sediment and algal bloom due to the distribution of ship route, navigation frequency and the properties of the ship route in the lake; to develop the coupled numerical models of multiple-class suspended solids induced by both ship travel and winds blow, and then to simulate and assess the accumulative impact process and extent for internal nutrient release from sediment and algal bloom in shallow lakes. The results of this research could provide useful technical supports for construction of ecological ship routes and control of internal pollutant release from sediment in large shallow lakes.

动力扰动下的内源营养盐释放是我国大型浅水湖泊蓝藻水华控制的难点，揭示其驱动机制成为认知内源缓冲能力的关键。我国大多数富营养化浅水湖泊（太湖、巢湖、滇池等）成灾的蓝藻水华具有表层漂浮、输移与空间堆积的特征，且大大受控于波浪与湖流。而这些湖泊大都同时承担着航运、旅游和渔业等功能，由通航产生的船行波将极大地改变湖泊波浪与湖流分布，对沉积物内源释放及蓝藻水华的空间输移、堆积均产生重要的影响。本研究将以太湖为例，基于野外站长期的观测数据积累和船行波、风生浪过程的定位观测，获取通航过程中典型船行波特征及其与风生浪叠加过程的水动力、营养盐、蓝藻水华参数，开发船行波扰动和风生浪作用耦合的多组分悬浮物数学模型，解耦船行波、风生浪对特定湖区营养盐和蓝藻水华的影响权重和相对贡献，评估船行波与风生浪对浅水湖泊水环境的累积影响过程和程度，以期为浅水湖泊生态航道建设和内源污染控制提供技术支撑。

动力扰动下的内源营养盐释放是我国大型浅水湖泊蓝藻水华控制的难点，揭示其驱动机制成为认知内源缓冲能力的关键。我国大多数富营养化浅水湖泊（太湖、巢湖、滇池等）成灾的蓝藻水华具有表层漂浮、输移与空间堆积的特征，且大大受控于波浪与湖流。而这些湖泊大都同时承担着航运、旅游和渔业等功能，由通航产生的船行波将极大地改变湖泊波浪与湖流分布，对沉积物内源释放及蓝藻水华的空间输移、堆积均产生重要的影响。本研究将以太湖为例，基于野外站长期的观测数据积累和船行波、风生浪过程的定位观测，获取通航过程中典型船行波特征及其与风生浪叠加过程的水动力、营养盐、蓝藻水华参数，开发船行波扰动和风生浪作用耦合的多组分悬浮物数学模型，解耦船行波、风生浪对特定湖区营养盐和蓝藻水华的影响权重和相对贡献，评估船行波与风生浪对浅水湖泊水环境的累积影响过程和程度，以期为浅水湖泊生态航道建设和内源污染控制提供技术支撑。