浅水湖泊群连通与调水的二维水动力-水质藕合模型研究

将湖泊群连通并进行引清调水的水环境污染治理模式在浅水湖泊分布比较集中的地区逐渐受到人们的关注.为了探究独立湖泊群相互连通引水后各湖区的水动力水质变化情况,以武汉大东湖生态水网工程的建设为背景,建立了湖泊群二维水动力-水质耦合模型.采用适合复杂边界的非结构化网格,考虑湖底地形和气候条件,考虑污染物的输入、迁移和转化,以及蓝藻等浮游生物的生长条件,分别利用东湖2006年6月和2007年6月的野外数据对所建模型进行参数的率定和校核,并利用2012年6月实测数据对3种引水方案与3种连通模式组合情况下湖泊群的BOD5,TP,TN以及Chl-a等生化指标的变化情况进行模拟,对稳定运行30 d后的模拟结果进行比较分析.结果表明:引水工程中,对于水域面积较大的湖泊,风力作用依旧是影响流场的主要因素;同样的引水流量下,不同的调水方案对水质改善结果有较大差别;湖泊群中隔堤的存在会给湖泊污染治理带来困难,而在湖泊群中适当区域设置生态小岛对水质变化过程影响微弱.     

复杂河网地区气候-水文-水动力耦合模型模拟

以淮河流域中下游结合部的洪泽湖周边滞洪区为研究对象,基于紧耦合技术,将一维和二维水动力模型进行耦合,基于松耦合技术,将气候模型与水文模型、水文模型与水动力模型进行耦合,实现了流域、河网、蓄滞洪区和湖泊复杂系统气候-水文-水动力单向耦合,并对气候变化影响下的复杂河网地区水流演进进行了模拟。结果表明:构建的气候-水文-水动力耦合模型对洪泽湖周边滞洪区洪水演进具有较好的模拟能力和适应性;气候变化导致未来淮河流域洪水量级增加,加大了洪泽湖周边滞洪区的洪水风险。     

博斯腾湖湖流及矿化度分布研究

根据大型内陆湖泊水动力、气象、水环境特征，建立了博斯腾湖二维水动力、矿化度数学模型，预测分析了不同风场、水文条件、水资源调度方案对湖流、矿化度空间分布的影响。研究发现：风场是湖流、矿化度空间分布的主要影响因素：吞吐流对流场、矿化度分布的影响居次要地位，但在静风条件下，吞吐流对取(进)水口附近的局部水域水流流态及矿化度空间分布特征有较大影响；水资源开发利用将对湖泊环境产生一定影响，在进行水工建筑物布设时，应综合考虑风力、风向、吞吐流等各种因素，进行方案比选。     

Relationships between wind-driven and hydraulic flow in Lake St. Clair and the St. Clair River Delta

A three-dimensional hydrodynamic forecasting model of the Great Lakes Huron-Erie Corridor is used to investigate mixing and the relationship between hydraulic and wind-induced currents in a shallow lake system in which lake inflows come through several channels of a river delta. The hydrodynamics in Lake St. Clair and the channels of the St. Clair River Delta are evaluated for (1) a one-year simulation from 1985 including water age calculation, (2) 8 different wind direction scenarios, and (3) a storm event. Observations and model simulations show distinct regions in the lake in which currents are forced by either hydraulic flow from the river system or from wind stress over the lake. However, during severe storm events, these regions are found to shift or even disappear due to changes in the delta channel inputs into the lake. These changes underscore the need for realistic, unsteady river flow boundary conditions at interfaces between a shallow lake and river delta. Steady inflow conditions will not allow for potential shifting of these current zones, and will also fail to resolve flow retardation or reversals during storm events.     

Our current understanding of lake ecosystem response to climate change: What have we really learned from the north temperate deep lakes?

Climatic change is recognized as an important factor capable of influencing the structural properties of aquatic ecosystems. Lake ecosystems are particularly sensitive to climate change. Several long time-series studies have shown close coupling between climate, lake thermal properties and individual organism physiology, population abundance, community structure, and food-web structure. Understanding the complex interplay between climate, hydrological variability, and ecosystem structure and functioning is essential to inform water resources risk assessment and fisheries management. The purpose of this paper is to present the current understanding of climate-induced changes on lake ecosystem phenology. We first review the ability of climate to modulate the interactions among lake hydrodynamics, chemical factors, and food-web structure in several north temperate deep lakes (e.g., Lake Washington, Lake Tahoe, Lake Constance, Lake Geneva, Lake Baikal, and Lake Zurich). Our aim is to assess long-term trends in the physical (e.g., temperature, timing of stratification, and duration of ice cover), chemical (e.g., nutrient concentrations), and biological (e.g., timing of the spring bloom, phytoplankton composition, and zooplankton abundance) characteristics of the lakes and to examine the signature of local weather conditions (e.g., air temperature and rainfall) and large-scale climatic variability (e.g., ENSO and PDO) on the lake physics, chemistry and biology. We also conducted modeling experiments to quantify the relative effect of climate change and nutrient loading on lake phenology. These modeling experiments focused on the relative changes to the major causal associations underlying plankton dynamics during the spring bloom and the summer stratified period. To further understand the importance of climate change on lakes, we propose two complementary directions of future research. First, additional research is needed to elucidate the wide array of in-lake processes that are likely to be affected by the climate change. Second, it is essential to examine the heterogeneity in responses among different water bodies. The rationale of this approach and its significance for dealing with the uncertainty that the climate signals cascade through lake ecosystems and shape abiotic variability and/or biotic responses have been recently advocated by several other synthesis papers.     

气候变化对可可西里盐湖流域湖泊水量变化的影响分析

湖泊是气候变化的敏感指示器。为了研究气候变化对湖泊水量的影响,以盐湖流域为研究区,应用统计方法对1989—2018年降雨、气温、蒸发进行线性趋势和突变分析,采用多源卫星遥感技术对湖泊面积等水文要素进行监测,分析湖泊面积与气象要素、湖泊面积与湖泊水量之间的相关性。利用VIC模型模拟径流并结合计算的冰川水量得到盐湖径流组成,定量探讨气象要素对湖泊水量变化的影响,综合分析2011年前后气象要素影响流域湖泊水量的差异。结合统计分析与水文模型定量计算可知:年降雨量、年平均气温显著升高,年蒸发量呈下降趋势,且与湖泊面积有较好的相关性。湖泊面积与湖泊水量间相关性较高,可间接体现气象要素对湖泊水量变化的影响。2011年前卓乃湖和盐湖水量变化主要受降雨量影响,库赛湖和海丁诺尔湖水量变化主要受气温影响;2011—2014年4个湖泊水量变化主要受降雨量影响;2015—2018年4个湖泊水量变化中降雨增加量、冻土释水和地下水补给增加量、冰川融水量对湖泊扩张的贡献约为34.48%、57.66%、7.86%,气温变化成为影响湖泊水量变化的主要因素,降雨量影响次之。     

极端气候事件对洞庭湖水文连通性变化的影响

为揭示洞庭湖近十几年水文连通性的变化特征并对其未来变化进行预测,研究极端气候事件在洞庭湖水文连通性变化中作出的贡献,使用水文连通性指数法、ETCCDI极端气候指数、Hurst指数以及数理统计分析方法进行研究。研究结果表明：洞庭湖水文连通性整体呈现夏季>秋季>春季>冬季的特征,夏季、秋季、春季和冬季的整体连通性指数均值分别为0.95、0.88、0.81和0.63,且洞庭湖的水文连通性在近30年比较稳定;经持续性预测发现洞庭湖水文连通性Hurst指数均大于0.5,表示其在没有人类活动干扰的情况下会在未来呈延续下降的趋势;洞庭湖水文连通性指数随着水位增加逐渐增加且增速逐渐放缓,水位增加对其具有正向影响的边际递减效应;极端降水事件对洞庭湖水文连通性具有较为明显的正向影响,而极端气温事件对洞庭湖水文连通性影响作用较小。研究结果有助于充分认识洞庭湖水资源演变规律,对保障洞庭湖流域水资源安全具有重要的理论和现实意义。     

大型浅水湖泊水动力特性数值分析

准确模拟太湖水流动态变化特性及水动力特征对模拟、预测污染物迁移转化规律以及理解水流运动与污染物相互作用机制具有重要的实用价值。以环境流体力学(EFDC)模型为基础,收集2009年-2010年水文、气象数据及湖区地形数据,并考虑引江济太工程对湖区的影响,建立符合太湖湖区水流特性的水动力模型。模型模拟结果表明最大风向、最大风速的组合方式模拟出来的流场情况最接近真实湖体流场,引江济太工程对湖流的影响微小,模型的水动力模拟效果良好。     

新疆博斯腾湖二维水动力数学模型研究

风场是影响湖泊水动力的重要因素,它可以改变水体运动速度和方向,影响各种物质在湖泊内的输移扩散。通过分析博斯腾湖大湖区风场,准确估算出风力、风向变化情况,构建了博斯腾湖平面二维水动力模型。应用计算模型对博斯腾湖水动力进行模拟预测,分析不同风向、风速对湖泊流场结构的影响,为进一步研究博斯腾湖水动力和污染物输移扩散提供理论依据。     

Drying Urban lakes: A consequence of climate change,urbanization or other anthropogenic causes? An insight from northern India

Urban lakes in many places around the world are rapidly becoming vulnerable because of such factors as urbanization, climate change, anthropogenic pollutant inputs, etc. The influence of such forcing factors on lakes hydrology must be correctly recognized and addressed in order to protect them over the long term. Facing similar challenges, Sukhna Lake, an urban lake in northern India, has apparently dried up frequently in the recent past. Numerous hypotheses were subsequently proposed to isolate the possible factors affecting the lake and its water budget, including the potential impacts of land use changes, climate change, anthropogenic activities and other natural processes. Using meteorological data, lake‐catchment information and a hydrologic model, these hypotheses were comprehensively analysed. Relevant data on rainfall, wind, temperature, lake inflows, groundwater, lake physical characteristics, catchment land uses, soil texture, etc., were gathered for the analysis. A temporal trend analysis of factors relevant to these hypotheses was undertaken to identify critical drivers of hydrological changes. A sensitivity analysis also was performed, using the lake water budget, to determine and prioritize the predominant factors affecting the lake, leading to the creation of an annual lake water budget for the period from 1971 to 2013, highlighting the lake inflows and outflows. The lake annual inflow (catchment run‐off) was computed by adopting a rainfall–run‐off model based on the SCS‐curve number. Lacking any anthropogenic water withdrawals, the outflow was quantified by estimating the evaporation loss (using the FAO‐based Penman–Monteith Equation). The results of the present study  indicate that the process of siltation and the construction of check dams in the catchment, rather than urbanization and climate change, were the dominating reasons contributing to changes in the lake hydrology, and affecting the lake most in recent years.     

鄱阳湖水利枢纽工程对水质环境影响研究

鄱阳湖水利枢纽工程的建设,将改变湖内水动力特性,进而影响鄱阳湖的水环境质量。采用水深平均的二维水动力-水质模型对鄱阳湖现状水动力和水质进行模拟验证,水陆边界模拟采用动边界技术,摸拟"高水湖相,低水河相"的湖泊水域变化特征,水质特性为枯水期水质较差,丰水期水质较好,靠近入湖河口的湖区劣于湖心水质,北部出湖水质较好的现状。模型模拟预测在现状外部入流边界和现状污染负荷条件下,3种不同运行方式下,鄱阳湖湖流的时空形态相应发生的变化和相应水质变化。计算结果表明,枯水期大部分区域的水质浓度下降,但尾闾等部分区域有所升高,开闸泄水期前后,水质较现状水质下降,敞泄期的大部分时间,较现状水质基本相似,蓄水期水质变化不大。水动力特性综合水质浓度的改变,增加了局部水体的富营养化风险。研究结果可为枢纽的建设提供科学依据。     

洞庭湖响水坎险滩的演变及成因分析

应用遥感地质和水动力演变分析法，分析了洞庭湖响水坎滩险的成因．探讨了影响湖区跌坎形成的水文和地质因素、水动力学条件及跌坎上、下游河床演变情况．地层岩性与沉积厚度的突变、地质构造单元分布等，是响水坎形成原始河床跌坎的内在原因，原始跌坎是出现跌水的前提，河湖边界及水流动力作用是跌水存在的外在条件，河湖水文组合决定了响水坎滩段是否碍航．     

洪泽湖换水能力的时空分布特征EI北大核心CSCD

为研究洪泽湖换水能力的时空分布特征,基于MIKE21建立洪泽湖二维水动力模型,模拟分析了洪泽湖不同湖区的换水周期;考虑洪泽湖的流场呈现风生流和吞吐流双重特点,分析了不同季节和不同风场条件下换水周期的空间变化特征。结果表明:洪泽湖换水周期空间异质性明显,从南到北梯度递增,冬季和春季全湖平均换水周期较长,分别为75 d和60 d,秋季和夏季的全湖平均换水周期较短,分别为49 d和31 d;实际风场对洪泽湖的换水能力起到正向作用,东南风对洪泽湖的换水能力起正向作用,东北风对洪泽湖的换水能力起到抑制作用。     

基于水质-污染源响应关系的抚仙湖水环境承载力计算研究

抚仙湖是中国最大的深水型淡水湖泊。随着流域入湖污染负荷的增加,其整体水质呈下降趋势,水污染呈自北向南和自沿岸向湖心推进的分布特征。本文依据水质-污染源响应关系,建立了基于湖泊水动力水质模型的水环境承载力计算方法;在对湖泊水动力和水质模型率定验证的基础上,计算得到了抚仙湖在规划水质目标(I类)下,CODMn、TN和TP这三类主要污染物的水环境承载力分别为20065.7 t/a、821.9 t/a和115.8 t/a;并根据抚仙湖环湖入湖河流及排污口分布特征,进一步提出了环湖分片主要污染物容许入湖负荷及污染物总量控制指标。     

岱海湖水位对气候要素与土地利用的响应

利用Mann-Kendall检验、Hurst系数法、基于有序聚类法的t检验等方法分析湖区水位演变趋势;利用Partial Mantel检验法,并通过构建缺失资料地区的湖区水文模型,探究了典型半干旱区湖泊岱海湖水位对气候要素与土地利用变化的响应。结果表明：岱海湖水位1959—2018年呈现显著下降趋势,于1982年和2005年发生突变,未来水位将呈现持续降低趋势;岱海湖春季受融雪影响导致水位较高,秋季受用水影响导致水位较低,且秋季水位降低在四季中最为明显;气候变化与水土资源开发利用是影响半干旱区湖泊水位变化的主要因素,在气候变化条件下,岱海湖水位对气温变化最为敏感,对日照变化的响应次之;由于岱海湖流域降水-产流-下渗机制较为复杂,岱海湖水位对降水变化的响应具有滞后性,流域林草面积增加可能是引发岱海湖水位降低的重要因素。     

暴雨对梁子湖水动力和水质的影响研究

为了分析在暴雨条件下,流域面源污染对梁子湖水质的影响,采用分布式流域面源污染模型,结合湖泊二维水动力水质模型,以暴雨产生的面源径流和污染负荷作为水动力水质模型的边界条件,构建了包含暴雨径流-面源模型与二维水动力水质模型的梁子湖水质模型体系。采用梁子湖水质的实测资料对模型进行了验证,其结果为面源模型的误差在15%以内,水质模型误差在20%以内,表明模型能模拟暴雨条件下面源径流和入湖污染物输入时湖泊水动力及水质的动态响应关系。以2010年7月11日暴雨过程为例,利用所建模型对暴雨前后梁子湖水质变化进行分析。模拟结果表明,水质受暴雨及污染物的冲击影响较大。     

Management Options to Improve Water Quality in Lake Peipsi: Insights from Large Scale Models and Remote Sensing

Nutrient pollution causes frequent blooms of potentially harmful cyanobacteria in Lake Peipsi (Estonia/Russia). Although external nutrient loading has reduced since the 1990s, lake water quality has barely improved, and eutrophication is still considered a threat to lake biota and water usage. To understand the recovery dynamics of the lake it is necessary to analyse the effects of land use and lake management on water quality to develop mitigation strategies. Comprehensive analysis has thus far failed due to information gaps inherent to conventional monitoring strategies. We show how two large-scale hydrological models using Earth observation data provide spatial information on pollution and can help explain the causes of past and current lake eutrophication. WaterGAP3.2 provides valid estimates of present and probable future phosphorus concentration in the lake water, based on past hydrological conditions. WaterWorld models spatial potential water quality and a scenario of optimal pollution reduction. Remotely sensed optical water quality data can be used to analyse recent, spatial water quality dynamics. The spatial and temporal algae distributions and can help explain eutrophication causes at Lake Peipsi and its catchment, adding value to in situ monitoring and supporting river basin management with large scale data.

     

风浪对浅水湖泊水质的影响机制

以太湖重要的浅水湖湾——东太湖为例,应用经典风浪经验公式,将风速转化为浪高,以直接体现风浪强度,在分析其与污染底泥卷起、水质指标相关关系的基础上,对风浪影响湖区水质的机制进行进一步探究。结果表明:随着风速、浪高的增加,水体浑浊度增加,偏北风作用下湖区浑浊度更高;DO的质量浓度呈降低趋势,全年浓度呈现冬季偏高而夏季偏低的规律;COD的质量浓度呈增加趋势,全年浓度呈现冬季偏高而夏季偏低的规律;TN的质量浓度与风速相关关系不明显,全年浓度呈现夏季偏高而冬季偏低的规律;浑浊度与COD存在较好的相关性。确定风浪对湖区水质的影响机制,旨在为针对性地制定湖泊水质改善措施提供技术支撑。     

城市景观湖泊水体交换的数值模拟研究

通过水流数学模型模拟城市湖泊流场分布是评估水体交换能力的重要依据。利用二维水动力数学模型研究了惠州西湖的水动力优化调控方案,探明了惠州西湖各状条件下水动力较差的区域,评估了引水对于惠州西湖湖水动力的改善程度,并对比了不同方案的的引水效果,进而提出了较好的引水方案。其成果可为惠州西湖和其他城市湖泊水质改善工程提供参考和借鉴。     

鄱阳湖水利枢纽工程对水质环境影响初步研究

鄱阳湖水利枢纽工程的建设,将改变湖内水动力特性,进而影响鄱阳湖的水环境质量。采用水深平均的二维水动力-水质模型对鄱阳湖现状水动力和水质进行模拟验证,水陆边界模拟采用动边界技术,摸拟“高水湖相,低水河相”的湖泊水域变化特征,水质特性为枯水期水质较差,丰水期水质较好,靠近入湖河口的湖区劣于湖心水质,北部出湖水质较好的现状。根据水利枢纽工程“控枯不控洪”的调度原则,模型模拟预测在现状外部入流边界和现状污染负荷条件下,三种不同运行方式下,鄱阳湖湖流的时空形态相应发生的变化和相应水质变化。计算结果表明,枯水期大部分区域的水质浓度下降,但尾闾等部分区域有所升高,开闸泄水期前后,水质较现状水质下降,敞泄期的大部分时间,较现状水质基本相似,蓄水期水质变化不大。水动力特性综合水质浓度的改变,增加了局部水体的富营养化风险。研究结果为枢纽的有效建设提供了科学依据。