莫莫格湿地位于吉林省白城市镇赉县，是国家的重点自然保护区，其中湿地内的白鹤湖是目前白鹤的主要停歇地。近年来，由于气候变化以及人类活动的影响，湿地内的水文过程及各个水体间的连通关系发现显著变化，造成白鹤湖地区频繁出现洪水、干旱等极端的水文事件，湖泊的水深、流速变动幅度剧烈，无法满足湖泊内植被的适宜生长条件，影响了白鹤的栖息环境。因此，如何准确定量研究白鹤湖的水动力变化特征，确定科学的水资源调控措施，已成为当地生态修复工作急需解决的关键科学问题。 本研究首先收集了保护区的水文气象数据，实地监测获得了白鹤湖的入流量、水下地形、水生植被分布等数据。以这些数据为基础，采用格子Boltzmann方法建立了适合于当地自然条件的水动力数值模型。模型考虑了白鹤湖周边水体——降雨、河渠、农田退水、地下水与湖泊间的水文连通过程，探讨了各个因子变动对白鹤湖流场的影响强度。模型模拟了不同降雨频率下白鹤湖湿地的水位变化，根据植被的适宜水深提出了各个月份在不同水文年下的水量调控策略。论文取得了如下的研究成果： （1）以水下地形数据、边界条件、水文气象数据及水生植被分布为基础，建立了面向白鹤湖湿地的二维水动力模型。数值模拟方法采用格子Boltzmann方法。为了准确考虑白鹤湖中水生植被对湖泊的阻力作用，外力项模型增加了非淹没情况下的刚性植被阻力模型。通过实测值和模拟值的对比，水深的模拟结果和实测结果平均偏差为4.94%，流速的模拟结果与实测结果相差4.70%，差异较小，说明建立的模型能较好地应用于白鹤湖水动力特征研究中。 （2）通过数值模拟确定了白鹤湖与其周边水体——河渠、农田退水、降雨、地下水产生水文连通关系时的湖泊流场特征。通过对白鹤湖流场2017年5月至6月进行模拟，发现白鹤湖水深较浅，最深处不到2m；流速较低且分布不均匀，湖泊的西部流速仅为0.032cm/s-0.23cm/s，湖泊东南部分流速为0.12cm-0.78cm/s。模型对影响湖泊流动性的各个因子进行了敏感性分析，得出对湖泊流动性的影响排名依次为：入流量、降雨、风速及植被密度。模型综合考虑了风速、植被密度、降雨和入流量这些因素，对白鹤湖7月份丰水期和9月份枯水期的流场进行了模拟，模拟结果显示白鹤湖在7月份丰水期的出口处平均流速为0.053m/s，9月枯水期平均流速为0.037m/s，9月份的出水口处的流速相比7月份降低了30.18%。9月份相对于7月份入流量、降雨、植被密度减少，风速变大。植被密度变小和风速变大将增加湖泊的流速，但由于这两个因子的影响强度弱于入流量及降雨量这两个因子，由此导致9月份的流速明显小于7月份的流速。 （3）当白鹤湖与地下水之间产生水文连通关系时，即湖泊和地下水之间产生水位差时，地下水对其水动力过程产生一定影响。研究结果表明，湖泊在夏季由于降雨的直接补给导致其水位整体大于地下水位，此时湖泊补给地下水，使得湖泊流速上升4.38%，水深下降0.71%。；而在秋季，地下水受到的蒸散发作用小于湖泊，导致地下水位整体大于湖泊水位，此时地下水反补湖泊，使得流速上升5.79%，水深上升0.91%。总体来看，地下水对于白鹤湖具有一定的储水或补水功能，丰水期蓄水、枯水期调水，对保持湖泊生态系统的稳定性具有一定作用。 （4）针对白鹤湖水文连通条件下的水生植被适宜生境的湖泊水动力特征进行了模拟。通过现场观测和实验室测定的方法确定了白鹤湖的主要水生植被适宜水位为0.3-0.4m。模型以丰水年、枯水年和平水年作为不同情景，以白鹤湖的目标区域水深满足植被适宜水深作为条件，对丰、平、枯水年三种情景进行了模拟，确定了入流量和出流量在各个月份的调节范围，并确定了水量调节策略。丰水年情况下，5、6月的入流量和出流量无需调整即可满足植被的适宜生长水深；7、8、9月由于来水较多，平均水深大于植被适宜水深范围，需要减少入流量以降低水深来满足植被适宜水深。平水年情况下，5月份来水不足，平均水深小于植被适宜水深，需降低出流量以增加水深确保满足植被的适宜水深；6月份无需调节即可满足植被生长适宜水深；7、8、9月份来水较多，需降低入流量以维持植被适宜生长条件。枯水年情况下，5月份来水不足，需通过降低出流量来维持植被的适宜水深；6、9月份无需调节即可满足植被适宜水深；7、8月份来水较多，需控制农田退水量以维持植被适宜水深。

Momoge wetland, located in Zhenlai County, Baicheng City, Jilin Province, is a key national nature reserve, and the main resting place of white crane is Baihe Lake in wetland. In recent years, due to the impact of climate change and human activities, the hydrological processes and the connectivity between different water bodies in wetlands have changed significantly. This has caused many impacts, such as the frequent occurrence of extreme hydrological events such as floods and droughts in Baihe Lake area, and the dramatic changes in the depth and velocity of the lake. As a result, the suitable growth conditions of vegetation in lakes can not be satisfied, and the habitat environment of white cranes is affected. Therefore, the key scientific problem urgently needed to be solved in the local ecological restoration work has become how to accurately and quantitatively study the hydrodynamic characteristics of Baihe Lake and determine scientific water resources control measures. The hydrometeorological data of the reserve were collected in this study, and the data of inflow, underwater topography and distribution of aquatic vegetation of Baihe Lake were obtained by field monitoring. Based on these data, the hydrodynamic numerical model suitable for local natural conditions is established by using the lattice Boltzmann method. The hydrological connection process of the water body around Baihe Lake, such as rainfall, River canal, farmland drainage, groundwater and lake, was considered in the model. The influence intensity of each factor change on the flow field of Baihe Lake was also discussed. The water level changes of Baihe Lake wetland under different rainfall frequencies were simulated by the model, and the water regulation strategies for different months in different hydrological years were put forward according to the suitable water depth of vegetation. The research results are as follows: (1) The two-dimensional hydrodynamic model for Baihe Lake wetland is established on the basis of underwater topographic data, boundary conditions, hydrometeorological data and aquatic vegetation distribution. Lattice Boltzmann method is used as numerical simulation method. In order to accurately consider the resistance of aquatic vegetation to lakes in Baihe Lake, a rigid vegetation resistance model under non-submerged conditions was added to the external force term model. By comparing the measured and simulated values, the average deviation between the simulated and measured results of water depth is 4.94%, and the difference between the simulated and measured results of flow velocity is 4.70%. The small difference between them indicates that the model established in the study of the hydrodynamic characteristics of Baihe Lake can be well applied. (2) The flow field characteristics of Baihe Lake are determined by numerical simulation when it is hydrologically connected with its surrounding water bodies, such as canals, farmland recession, rainfall and groundwater. By simulating the flow field of Baihe Lake from May to June 2017, it is found that the water depth of Baihe Lake is relatively shallow, with the deepest depth less than 2 m. Data show that the velocity of flow is low and the distribution is not uniform. The velocity in the west of the lake is only 0.032 cm/s-0.23 cm/s, and in the southeast part of the lake is 0.12 cm-0.78 cm/s. Sensitivity analysis of the factors affecting lake fluidity was carried out through the model, and the ranking of the factors affecting lake fluidity was as follows: inflow, rainfall, wind speed and vegetation density. Wind speed, vegetation density, rainfall and inflow are taken into account in the model. The flow field of Baihe Lake during the rainy season in July and the dry season in September was simulated and analyzed. The simulation results show that the average velocity at the outlet of Baihe Lake during the rainy season in July is 0.053 m/s, and that in the dry season in September is 0.037 m/s. The flow velocity at the outlet in September was 30.18% lower than that in July. Because compared with July, the inflow, rainfall and vegetation density decreased as well as the wind speed increased in September. The decrease of vegetation density and the increase of wind speed will increase the flow rate of the lake. However, the influence intensity of these two factors is smaller than that of inflow and rainfall, which results in the flow rate in September is significantly lower than that in July. (3) When there is a hydrological connection between Baihe Lake and groundwater, that is, when there is a water level difference between lake and groundwater, groundwater will have a certain impact on it in the hydrodynamic process. The results show that in summer, the lake water level is larger than the groundwater level as a whole due to the direct recharge of rainfall. At this time, the lake recharged groundwater, making the lake flow rate increased by 4.38%, water depth decreased by 0.71%. In autumn, because of the evapotranspiration, the groundwater level is smaller than that of the lake, which leads to the groundwater level being larger than that of the lake as a whole. At this time, the groundwater recharges the lake, which increases the velocity by 5.79% and the water depth by 0.91%. Generally speaking, groundwater has a certain function of water storage or recharge for Baihe Lake. Water storage in flood season and water diversion in dry season play a certain role in maintaining the stability of Lake ecosystem. (4) Under the condition of hydrological connectivity of Baihe Lake, the hydrodynamic characteristics of lakes with suitable habitats for aquatic vegetation were simulated. The suitable water level of the main aquatic vegetation in Baihe Lake is 0.3-0.4m, which is determined by field observation and laboratory measurement. The three scenarios of high, flat and low water years were simulated by using the model with different scenarios of high water year, low water year and flat water year, and the water depth of Baihe Lake's target area satisfying the suitable water depth of vegetation as the condition. The regulation range of inflow and outflow in each month was determined, and the water regulation strategy was determined. Under the condition of abundant water year, the suitable growth depth of vegetation can be satisfied without adjusting the inflow and outflow in May and June. However, in July, August and September, the average water depth is larger than the suitable depth of vegetation because of the large amount of incoming water. Therefore, it is necessary to reduce the inflow to reduce the water depth in order to make the suitable water depth of vegetation be satisfied. In a normal year, due to insufficient water supply in May, the average water depth is less than the suitable water depth of vegetation. It is necessary to reduce the discharge to increase the water depth to ensure that the suitable water depth of vegetation is satisfied. The suitable water depth for vegetation growth can be satisfied without regulation in June. In July, August and September, there is more water coming, so it is necessary to reduce the inflow to maintain the suitable vegetation growth conditions. In dry years, due to insufficient water supply in May, it is necessary to maintain the appropriate depth of vegetation by reducing outflow. The suitable water depth of vegetation can be satisfied without regulation in June and September. In July and August, there is more water coming from farmland. It is necessary to control the amount of water withdrawing from farmland in order to maintain the suitable depth of water for vegetation.