围填海活动（Coastal Reclamation）是海岸带人类活动的主要方式之一，随着全世界城市化与工业化进程的加剧，沿海地区对于土地的利用需求日益增加，导致滨海地区围填海工程规模不断扩大。然而，大规模的围填海工程活动会对滨海环境与生态系统带来严重的负面影响，引起近海滩涂与滨海湿地的丧失，对局部海域水动力环境造成扰动影响，产生海岸侵蚀与泥沙淤积的风险，破坏原有的生物栖息地，改变生态系统的功能与结构，尤其对于大江大河三角洲地区，由于河口三角洲地区本身的生态系统就相对脆弱，因此，沿海围填海工程对河口生态系统产生深远的影响，大大增加了相关的管理活动的复杂性和不确定性。因此，了解围填海活动对近岸河口生态系统的综合影响与响应是十分必要的。目前针对围填海工程的环境影响方面的研究，从水动力、水生态以及水环境的影响基础上，发展到结合3S技术与海洋模型预测技术，对围填海活动进行预测与管理。如何科学认识围填海产生的环境生态效应的机理机制，通过学科交叉的方式降低围填海工程的负面影响是研究的重要问题。 本论文旨在通过对围填海工程活动的讨论，探明温盐梯度、泥沙淤积共同作用下的水动力变化内在机制；重点深入分析了围填海过程对生境适宜性以及种群动力过程的影响；量化围填海引起的系统扰动与生态阈值；构建水动力-水生态过程耦合的动力学模型；针对不同的围填海工程类型，确定潜在的生态风险区域，完善评价围填海强度指标体系的建设，确立围填海工程生态影响评价标准等级；对围填海工程进行优化设计，提出未来面向生态系统的海岸工程设计理念，面向工程开发者与决策者提出建设性意见，为围填海工程的合理实施与综合管理提供科学的理论基础。取得以下主要研究结果： (1) 明确了填海工程引起的温度-泥沙共同作用下的水动力变化机制及其对水生生物的生境的影响，认为填海工程活动的开发会导致流速增加，对流场系统产生扰动。 在模拟过程中考虑了自然状态和吹填后状态两种情景，可用来对比分析沿海围垦活动时的流场变化。在仿真过程中，多相流模型与浮游植物生长的有限元模拟方法（MEHD-AGSA）将被耦合到一个通用的建模框架中。在垂直方向上可以有效地反映水体中的物理流的详细变化以及适宜浮游植物生长区的相应反应。这种方法将加强传统模拟方法（其侧重于水动力变化的单一方面，忽略了对生态过程潜在生境适宜性的影响），并模拟生态系统对改变水环境条件的反馈。研究结果表明，在没有人为干扰的情况下，流速比原始状态高16.7%。此外，吹填工程缩短了泥沙沉降路径，导致沉积物直接向海洋增加，削弱了旋流，降低了物质交换能力。在原有条件下，沉积物体积分数的分布仍然很高，反映了水体自净能力强的特点。在垂直方向的浮游植物生长的适宜生境分布反映了围填海造成的生态退化。此外，沿海围垦活动将导致生长适宜指数（GSI）的减少，从而使浮游植物物种的生境稳定性降低约4～12%。GSI指数也可应用于海岸填海工程的管理和设计中，以尽量减少对生态的影响，这将有助于识别在水动力扰动下水生生物适宜生境分布。 (2)阐明了围海工程引起的水动力扰动，确立了每一类群生物体的水动力扰动与生态阈值计算方法，认为围海活动对自游类生物生命活动的影响最为剧烈与敏感。 以黄河三角洲北部的东营港为案例研究区，构建了围海引起的水动力扰动模型，确立了IHD指数的计算方法。选取了约11个采样区的数据用来做案例分析。并在每个采样区1km2的范围内，通过对围海工程中一个典型区域的水动力扰动分布的比较，将各监测区进一步划分为受影响区和非影响区。另外根据水下的力学特性，水生生物分为固着生物、悬浮生物和游动生物三大生物类群。识别水动力扰动对不同类型的水生生物的影响，确立水动力扰动的时空分布。构建了IHD指数，可以用于评估围海引起的水动力扰动强度，可以为围填海的综合管理提供指标参考。 结果显示，围海活动一般流速会降低却增强了对生态系统的扰动，影响大部分水生生物的生长稳定性。此外，对于不同类群的水生动物，水动力扰动强度和相关的生态阈值也不同：对于固着类生物，围海引起的水动力扰动在受到围海活动影响区要低于非影响区约24.46%左右，也就是说，由围海活动引起的水动力扰动对固着类生物生长行为有较低的抑制或破坏作用，即对围海引起的水动力扰动不敏感；对于悬浮类生物，围海影响区的水动力扰动强度高出这生态阈值约3.55%左右，即围海引起的水动力扰动对悬浮/漂浮类生物比较敏感；对于自游类生物，围海活动影响区的水动力扰动比非影响区平均高出约40.44%左右，这表明由于围海活动引起的水动力扰动对自游类生物的影响最大。事实上，自游类生物在围海活动影响区的水动力扰动平均比生态阈值高出23.11%左右，即围海引起的水动力扰动对自游类生物极度敏感。 (3) 反映了在人工构筑物影响下的种群动力学特征（包含个体生长与迁移模式）与生境适宜性之间的联系，认为线性阻隔物是能兼具安全-生态的工程类型。 基于三种围填海构筑物（DD型、LD型与FD型）的不同，构建了40组数据集与三组数值实验。实验结果表明，FD型人工阻隔物对种群动态的影响大于LD和DD型阻隔物。其中FD型阻隔物的衰减率比LD型阻隔物高出10.22%，表明FD型阻隔物对目标物种的影响比LD型阻隔物更显著。此外，还发现人工阻隔物也会影响栖息地的适宜度，由阻隔边界造成的内部空间生境适宜度的下降速度远远大于外部空间。结果表明，与FD型人工阻隔物比对，LD型人工阻隔物更有利于保护海岸生物的生态平衡，其对种群动态与栖息地适宜度的影响都较小。它不仅提供了较低的系统内扰动，而且兼具类似DD型人工阻隔物的功能，有较高的生态连通性。在满足海岸线保护要求的基础上，LD型人工构筑物将成为今后海岸工程设计和管理的重要参考类型。其内在机理可为今后环境友好型海岸工程设计提供有效的理论依据。 (4) 构建了围填海强度指数（CRI）的量化方法，认为港口建设对生态环境的影响最大，而近几年黄河三角洲地区的围填海活动强度呈现上升趋势。 在黄河三角洲地区，相比于其他类型的围填海工程活动，港口建设对水动力条件的影响高出其余工程类型平均约72.78%左右，而对生态状况指标的影响高出其余工程类型平均约65.03%左右，对经济成本指标的影响高出其余工程类型平均约75.03%左右，对工程强度的影响高出其余工程类型平均约66.35%左右；此外，水产养殖工程对水质状况的影响最大，高出其余工程类型平均约42.51%左右；堤坝防护工程对景观的影响最大，高出其余工程类型平均约51.75%左右。综上所述，港口建设对生态环境的综合影响最强；通过构建EDI指标体系，看到近些年来黄河三角洲的生态退化程度不断增加，EDI指数在2015年左右达到0.5895，比之前升高了约5.97 %，评级已经接近IV级，这意味着围填海活动影响黄河三角洲生态环境面临着不断退化；另外，根据围填海强度指数的计算发现，近15年来，由于河口开发活动的增大，CRI已经上升到了更高层级，影响更为剧烈，相比2000年，2015年的CRI增长率达到37.97 %左右；而2005年相比2000年的CRI增长率约为16.54 %，这意味着近些年黄河三角洲地区的海洋围填海活动更加密集，也侧面反映了围填海活动的现状，体现了围填海活动对滨海生态环境的综合影响。 (5) 提出了面向生态系统的生态海堤设计理念，构建了一套完备的围填海工程优化计算体系与框架； 对生态海堤工程参数（包括L1、L2、α、h1）进行了优化设计。通过CFD数值模拟与水槽试验相结合的方法，确定了相关参数的设计范围。对于陡坡式海堤，L1的确定有助于降低坝体对集水区的扰动，根据实验，当L1较大时，这种扰动相对较小，其Hs几乎等于对照组数据（Hs=37.2 cm）；当L1较大时，集水区的扰动更大（Hs=42.7 cm）；当L1刚好等于一个波周期的距离时，存在一个极低值，此时Hs=33.8 cm；对于参数L2，当L2间距过大，那么人工育滩对于来流水体的影响更小，其数据上与对照组数据相近（Hs=39.8 cm）；当L2间距过小时，来流水体在经过人工育滩时会对水体产生强烈扰动（Hs=41.7 cm）；只有L2当间距保持在适当的距离时，此时的Hs存在极低值（Hs=37.2 cm）。对于斜坡倾角a，随着坡角的增加，Hs在缓慢增加；对于参数h1，当人工育滩高于水位时，对波高的变化普遍存在负影响，即降低了波高Hs。相关参数的取值范围：L1∈[0.1, 0.3]; L2∈[0.2, 0.8]; a∈(30,60]; h1∈[0.2,0.4]。此外，用拉丁超立方抽样方法确定了50组样本集。从优化结果得到的生态海塘最优解集，可为未来生态海堤在实际工程项目中的设计提供理论支持。丰富了未来海岸工程的设计理念与思路。

Coastal reclamation is one of the major ways of human activities in the coastal zone. With the intensification of urbanization and industrialization in the world, the demand for land use in coastal areas is increasing, leading to the continuous expansion of coastal reclamation engineering in coastal area. However, large-scale reclamation activities will bring serious negative impact on the coastal environment and ecosystem. For instance, lossing inshore beaches and coastal wetland, causing hydrodynamicd isturbance in local area, increasing the risk of coastal erosion and siltation, destructing the original habitat and changing the structure and function of ecosystem. Especially for the river estuary area, the coastal reclamation projects have a profound impact on the estuarine ecosystem. Therefore, it is necessary to understand the comprehensive influence and response of coastal reclamation to the coastal ecosystem. According to the theory of hydrodynamics, water ecology and water environment, the research on environmental impact of coastal reclamation have been developed to predict and manage reclamation activities combining 3S technology and marine model. How to scientifically understand the mechanism of environmental and ecological effects caused by coastal reclamation is an important research topic. The objective of this article is to discuss the internal mechanism of hydrodynamic change under the interaction of thermohaline gradients and sediment deposition; depth analysis the coastal reclamation impact on population dynamics and suitable habitat; quantify the hydrodynamic disturbance and ecological threshold caused by coastal reclamation; establish dynamic model coupled hydrodynamic and water ecological process; for the different types of coastal reclamation engineering, determine the potential ecological risk areas, improve the indicators system to assess coastal reclamation intensity; optimize coastal reclamation engineering, propose the design concept of ecosystem-based coastal engineering. Constructive suggestions are put forward for engineering developers and decision-makers to provide a scientific basis for the rational implementation and comprehensive management of reclamation projects. The work undertaken and the achievements are as follows: (1) Clarifying the mechanism of hydrodynamic variation under the interaction of temperature and sediment caused by sea filling engineering and its effects on the habitat of aquatic organisms. It is considered that the development of the filling engineering will lead to the increase of flow rate. About two scenarios, including original condition and after coastal reclamation activities are involved in simulation processes, which can be used as a contrast to analyze the variation of flow field under coastal reclamation activities. In the process of simulation, a multiphase finite-element hydrodynamic and phytoplankton growth simulation approach (MEHD-AGSA) will be coupled into a general modeling framework. Detailed variations of the physical currents in the water and the corresponding responses of the suitable growth areas for multiple phytoplankton species can be effectively reflected over the vertical direction. This approach will enhance traditional methods which focused a single aspect of hydrodynamic variation and ignored the effect on potential habitat suitability and simulate responses of ecosystems towards changing aquatic environmental conditions. According to the results, water velocity was 16.7% higher than that of original state without human disturbances. Also, the related filling engineering shortened sediment settling paths, leading to increased amount of sediments into the ocean directly, which weakened the vortex flow and reduced the capacity of material exchange. The distribution of sediment volume fraction remained high under the original condition, mirroring the strong ability of self-purification for water body. The optimal suitable areas for phytoplankton growth in vertical direction reflected the ecological degeneration from human reclamation manifestly, the significant slash on the adaptable habitat for phytoplankton started up when coastal reclamation engineering accomplished. Additionally, coastal reclamation activities would lead to the decrease of the growth suitability index (GSI), thus it could cut down the stability of phytoplankton species approximately 4~12%. The proposed GSI can also be applied on the management and design of coastal reclamation projects to minimize ecological impacts. It would be helpful for facilitating identifying suitable phytoplankton growth areas under physical disturbances. (2) Explaining the hydrodynamic disturbance caused by sea reclamation works, a method for calculating the hydrodynamic disturbance and the ecological threshold of each group of organisms is established. It is considered that the influence of reclamation activities on swimming organism can be largely intense and sensitive. The related ecological threshold values were calculated for predicting the distribution of intensity of hydrodynamic disturbance (IHD) through using the case of Dongying port, China. Eleven monitoring areas (i.e. from A1 to A11, approximately 1km2 each) in Dongying Port of China (located in the Yellow river delta) are considered. Each monitoring area is further divided into the affected and non-affected areas based on impact of coastal reclamation engineering by comparing the distribution of hydrodynamic disturbance, which represented one typical district under coastal reclamation activities. According to the classification of coastal engineering, each monitoring area was further divided into affected and non-affected areas for comparing the distribution of hydrodynamic disturbance in different conditions. Based on the mechanical characteristics under water, aquatic creatures were categorized as three biological groups: sessile, suspended and swimming organisms and reclassified the common parts of aquatic organisms in the studied areas. It was considered that coastal reclamation activities could enhance the hydrodynamic disturbances, which would impact growth stability of coastal aquatic creatures. Furthermore, the intensity of hydrodynamic disturbance for each type of aquatic creatures (i.e. I1 for sessile organisms, I2 for suspended organisms and I3 for swimming organisms) and the related ecological threshold were reported: the value of I1 for the affected area was 24.46% lower than that of the non-affected areas in average. In other words, the hydrodynamic disturbances caused by coastal reclamation introduced less damage for sessile organisms’ growth than natural scenario on the hydraulics, which was insensitive to CRHD; the maximum ecological threshold value for sessile organisms was approximately 3.5%, that is to say, the mechanical characteristic for suspended organisms was disadvantageous for growth and habitat, which was sensitive to CRHD; the value of I3 for affected area was 40.44% higher than that of the non-affected areas in average. The hydrodynamic disturbances were disadvantageous for growth of swimming organisms, which was extremely sensitive to CRHD. Actually, the value of disturbance intensity for swimming organisms was about 23.11% exceeding the threshold value. Consequently, the coastal reclamation activities had much negative effects on the life cycle of swimming organisms. (3) Reflecting the relationship between the population dynamics and habitat suitability under the influence of artificial structures. It is considered that the linear type of barriers can be included the function of both safe and ecological protection. Three barrier types (i.e. DD, LD and FD) caused by artificial structures were discussed here. Totally, 40 data sets and three simulation experiment were produced. According to simulation experiment, the FD type of artificial barriers had much more impacts on population dynamic and habitat fitness than those of the LD and DD types of barriers. Additionally, it was concluded that artificial barriers could also impact the habitat fitness. The decline rate in the inside region was much greater than that in the outside region. Furthermore, the decline rate for the FD type was 10.22% higher than that for the LD type, demonstrating that the FD type barrier had more pronounced impacts on target species than that of the LD type. As the results, the LD type of artificial structure would thus be more conducive to protecting the ecological balance of coastal organisms than that of the FD type of artificial barriers. It not only provided much lower systemic disturbance on the inside region than that of the FD type, but existed high ability of ecological connectivity. On the basis of satisfying the requirements of coastline protection, the LD type of artificial structure would be an important reference type for coastal engineering design and management in future. The internal mechanism may provide effective theoretical fundament for environmental-friendly coastal engineering design in the future. (4) Established a quantitative method to calculate the coastal reclamation intensity (CRI). It was considered that the impact of port construction on the ecological environment was the largest. In recent years, the CRI have upward trend in the Yellow River estuary. In the Yellow River estuary, the port construction impacting on hydrodynamic conditions, ecological status, economic costs and engineering intensity were averagely 72.78, 65.03, 75.03 and 66.35% higher than those of other engineering types, respectively. Furthermore, fisheries aquaculture impacting on water quality was averagely 42.51% higher than that of other engineering types. Seawall defense impacting on landscape variation was averagely 51.75% higher than that of other engineering types; the petroleum exploitation is impacted on each functional group. Therefore, the port construction type has the strongest comprehensive response on coastal ecological environment. According to the results, EDI in Yellow River estuary has increased unceasingly in recent years. EDI in 2015s rose by 5.97% to 0.5895 closed to degree IV, which states that the ecological degradation process is relatively serious. Most of EDI achieved at degree III, represented as the moderately degradation. Furthermore, the IHD in Yellow River estuary was rising up continuously in recent years, which had increased about 45.4% from 2000 to 2015. At last, the CRI was expanded unceasingly in recent years. The specific value in 2015 was about 0.7551; the specific value in 2000 was about 0.5473. In other words, the CRI was climbed to a higher intensity level in resent 15 years. The growth rate in 2015 compared to 2000 was about 37.97%.The results could provide a reference indicator of coastal reclamation management for policy makers to assess the combined effects, and supply the basis of identification of ecological red lines. (5) Put forward a design concept of ecological-based seawall, and set up a complete set of optimization calculation system and framework for the coastal reclamation. A multi-objective optimization method coupled with Kriging model was used to optimize engineering parameters (including L1, L2, a and h1) of eco-seawall. Furthermore, the range of relevant parameters was determined and verified numerically by the combination of CFD numerical simulation and flume experiment. According to experiment, when L1 is large, it will lead to smaller effects between artificial nourishment and dam, which substantially equal to control group data without artificial nourishment (HS =37.2cm in average); when L1 is small, it will produce intensive disturbance (HS =42.7cm in average); when L1 is close to a length in a wave period, it will have a minimum of HS (HS =33.8cm in average), this is because the reflection wave have largely dissipated in a L1 range, and the incident wave just enter at this moment, which lead to the minimum disturbance.For the distance between two artificial nourishment (L2), the variation of Hs with L2 decreases first and then increases. In other words, the parameter of L2 exist significance difference affecting on Hs. When L2 is large, it will lead to smaller effects between two artificial nourishment, which substantially equal to control group data without artificial nourishment (HS =39.8cm in average); when L2 is small, it will produce intensive disturbance (HS =41.7cm in average); when L2 retains the proper distance, it will have a minimum of HS (HS =37.2cm in average). For slope angle (a) of dam, the influence is large. With the decrease of slope angle, the HS can also grow slowly; For the height of artificial nourishment (h1), it is concluded that water level is an important factor determining the change of h1. Additionally, the design domain is obviously reduced: L1∈[0.1, 0.3]; L2∈[0.2, 0.8]; a∈(30,60]; h1∈[0.2,0.4]. About 50 groups of optimal parameters are determined by Latin hypercube sampling method. The optimal solution set of eco-seawall obtained from the optimization results, can provide the optimal design range for the practical engineering design.