Second sea－entering approach of Changjiang River： Tongl Canal－planning of control dimensions， analysis of erosion and siltation and selection of outlet

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广利河口拦门沙的沉积特征与冲淤过程的研究

为给广利河口航道的建设提供科学依据,通过对研究区现场调查,查明了广利河口拦门沙水动力特征、海底地形、底质特征和地层垂向分布特征。在进行沉积物分析与历史资料对比分析的基础上,探讨了拦门沙体的沉积特征和冲淤过程。分析认为,广利河口拦门沙是在浅海-潮坪基础上接受广利河、支脉河和溢洪河携运泥沙堆积而成,海岸滩涂沉积物和黄河口水下岸坡物质对拦门沙的发育也产生了一定的影响。在河流和海洋动力作用的改造下,现在拦门沙基本进入冲淤平衡时期。但近期由于人工因素的影响,拦门沙顶出现暂时的淤积。研究结果还表明：拦门沙体北侧水动力作用明显强于南侧,航道设计为东偏南较好。     

模型变率对斜坡上泥沙起动相似影响研究

本文在前人的理论分析及水槽试验工作的基础上，分析了上举力系数对边坡泥沙起动影响，研究了常用模型沙（木屑、煤屑、电木粉），以平床泥沙起动相似设计，变态模型变率对边坡及水流纵向坡面上泥沙起动相似偏离影响     

长江口北支河口地貌特征及演变趋势分析

根据近年来侧扫声纳、单波束等野外调查资料,对长江口北支河口地形地貌特征进行了分析。分析结果表明,研究区内水深变化从0~20m,海底地形总体上由西向东倾斜;区内地貌特征主要由两个拦门沙、两个深槽以及一个沙脊组成。同时,利用历史海图与实测水深数据进行了对比分析,分析了研究区内地形地貌的演变趋势。     

新沂河海口控制工程闸下河道冲刷试验研究

新沂河海口控制工程深泓闸闸下泓道长约１．３ｋｍ,河床由淤积历时较长的淤泥质粘性土组成。试验中首先取原状土土样,通过水槽试验确定起动流速,据此选择模型沙和进行模型设计。试验表明,下游河道冲刷主要由过闸水流及河口跌水造成,其中,前者形成的冲刷坑为设计的控制条件。根据试验结果认为,对于新沂河海口控制工程这样流量大、河口潮位低的闸下泓道,冲刷是不可避免的,建议放弃海漫防冲的方法,改设板桩截墙。试验中采用的某些观点和方法,对于淤泥质粘土海岸地区河口段闸下冲刷研究具有一定的参考价值。     

Methodology for estimation of river discharge and application of the Zhujiang River Estuary(ZRE)

The ZRE is a very complicated estuary with multi-river inlets. The total sum of river discharge in the upstream(away from the tidal influence region) of the Zhujiang River can be easily measured. However, when the total river discharges into the estuary from eight inlets, it is a very difficult task to obtain a continuous river discharge flux data from each branch of the Zhujiang River. However, the different ratios of river discharges between the river branches can significantly affect the estuarine circulation feature and baroclinic process. Moreover, the accuracy of numerical forecast for the estuarine circulation is very much dependent on the accuracy of the time history of the river discharge flux for each branch. Therefore, it is important to estimate river discharge from each branch in order to improve the accuracy of the model forecast for the circulation of the ZRE. The development of a new estimation method of the river discharges is focused on based on the system identification theory, numerical modeling and the time history data from the CODAR observed sea surface current. The new approach has been appfied to estimating the time history (hourly) of river discharge from each branch in the upstream of the ZRE.     

长江口北支入海河段的衰退机制

通过不同时期海图、水下地形图对比,论述了长江北支入海河段具有沙脊发育、河槽淤浅、南涨北塌、深泓北靠并逐渐向北平移的演变特征和衰退态势。据2003年11月同步潮位、潮流、悬沙和地形资料,经单宽潮量、输沙量和断面进出潮量计算发现：黄瓜沙北水道水沙大进大出以过往为主,南水道是水沙倒灌的主通道,潮速南小北大是河道南涨北塌并向北平移的动力机制,南水道涨落潮流均携沙输向江心是江心沙脊发育、黄瓜沙淤高的物质基础,进潮量大是导致泥沙倒灌、入海河段衰退的主要原因。     

Tidal Flat Morphodynamic Processes of the Yangtze Estuary and Their Engineering Implications

—The intertidal flats are classified as"attached bar"."spit"and"isolated bar"in relation to theland.and"broad flat","sharp bank"and"eroded cliff"according to the shape of the cross-shore profile.Tidal currents on the flat are basically back and forth along the river channel banks but gyratory on theseaward side of the Chongming Island.The flow velocity on the intertidal flat is gradually reduced with in-creasing elevation.The river discharge strengthens ebb flows and modifies current asymmetry especiallyon the lower flat in neap tide.although hydrodynamics over the tidal flat is tide-dominated.The waveheight on the tidal flat is normally limited to a few decimeters although it changes with water depth.slopeand wind.Suspended sediment concentration over the tidal flat is typically hundreds to thousands ofmg/l.Although the delta has grown rapidly in history.the rate of growth is different in different periods.A maximum advancing rate of 330m/a was recently found in the central part of the river mouth towa     

长江径流变化对南港盐水入侵影响分析

根据长江大通站长系列流量资料，按不同频率把枯季流量划分为丰，平，枯，特枯四类，并与吴淞，高桥氯化物进行对比分析，表明南港河段每年受到盐水入侵的影响，但入侵强度各年相差甚远，主要受控于径流量的丰竭，三峡工作兴建后对长江口咸潮影响，既有不利的一面，又有有利的一面，建议水库调蓄方式根据实际情况调整。     

感潮河段船闸下引航道水沙运动及泥沙淤积

通过建立一维非恒定水流泥沙数学模型,对规则断面引航道中的水流泥沙运动规律及淤积特性进行了数值模拟计算,并对影响感潮河段船闸下泥沙淤积的各种因素(如干支流水位差、开通闸水头差、主流潮差等)进行了深入分析和研究。研究结果可为有关工程设计及运行管理提供参考。     

Technology for bottom relief and sedimentation surveys of White-Sea river estuaries

Experimental bottom relief survey technology and investigation results are presented. Investigations were conducted over about six years at several White-Sea river estuaries onboard the R/V Ecolog. Geomorphology data was obtained using an instrument complex that included an MKS, Microsound side scan sonar, AP-5 acoustic profiler, and LMS-350 echo sounder. ECHOGRAPH and WINRASTR original software was used for data gathering and processing.     

长江口和杭州湾海域生物生产力锋面及其生态学效应

通过分析海洋生态学资料并结合卫星遥感、渔场及赤潮等资料,发现长江口和杭州湾及其毗邻海域生物生产力的锋面,在离长江口门和杭州湾口约100 km的长江冲淡水中部海域出现蓝细菌丰度、浮游植物现存量和初级生产力以及浮游动物的最大值,该锋面的存在和位置被水色遥感所确认.光和营养盐在此呈现最佳的权衡.在该锋区悬浮体浓度小于5 mg/dm3,盐度为25～30.在该锋面的西侧高的悬浮体浓度造成了浮游植物的光限制,其东侧距长江口和杭州湾口较远,陆源营养盐被稀释,加之浮游植物的消耗,造成了营养盐的限制.夏季水体的层化,增强了水体的垂直稳定,使这种分布格局更加显著.由于细菌多附着在悬浮颗粒物的表面,细菌丰度的最大值出现在近口门区的最大浊度带,在向外海方向随着悬浮体的沉降细菌丰度迅速降低.在生物生产力锋面,浮游植物的旺发导致水体跃层之上高溶解氧浓度和低营养盐浓度,尤其是PO4被耗尽,同时浮游动物饵料的丰富,造成浮游动物旺发;由于蓝细菌的快速增殖,其流式细胞测定的细胞粒径变小.生物生产力锋面的出现产生了显著的生态学效应,一方面造成某些经济鱼类产卵和索饵场的形成,例如鲐鲹鱼、马鲛鱼等;另一方面造成赤潮多发区和底层水缺氧区.     

唐山国际旅游岛内海水环境改善措施试验研究

文章基于潮流物理模型,研究分析了唐山国际旅游岛内海水动力和水体交换能力特性。研究结果表明,东侧排水河河宽度现有宽度较窄,内海东侧水流动力较弱,水体交换能力相对较差。拓宽排水河宽度,能有效增强内海东侧水动力,提高水体交换能力。适当拓宽排水河宽度,能改善唐山国际旅游岛内海水环境。     

调水调沙后黄河口邻近海域浮游植物群落响应特征

为研究黄河调水调沙对邻近海域浮游植物群落的影响,2013年7月在黄河第16次调水调沙事件后,开展了水文、化学与生物综合调查。研究结果表明,黄河口邻近海域温度、营养盐浓度整体呈现由河口向离岸区域逐渐递减的分布趋势,盐度呈现由河口向离岸区域逐渐递增的分布趋势,显示了黄河水输入的影响程度。叶绿素a与营养盐浓度在空间分布上呈现出较好的对应关系,在黄河口偏渤海湾侧明显高于偏莱州湾侧,且近河口区明显高于离岸区。营养盐结构分析表明,黄河口邻近海域普遍存在磷酸盐(DIP)的绝对和相对限制;但黄河水沙输入在局部站位缓解了硅(DSi)限制。浮游植物群落结构的空间变化显著受到盐度的影响,在受黄河水输入影响显著的C、D、E断面,蓝藻与绿藻的生物量比例明显增高;影响相对较弱的断面则以硅藻、甲藻为主。浮游植物群落结构与环境因子的主成分分析结果表明,DSi、DIP和盐度是影响该海域浮游植物空间变化的关键环境因子。甲藻、蓝藻与绿藻群落受盐度变化的影响程度明显大于硅藻群落;但甲藻群落对营养盐结构的敏感性低于硅藻、蓝藻和绿藻群落。     

Along-coast shifts of plankton blooms driven by riverine inputs of nutrients and fresh water onto the coastal shelf: a model simulation

Rivers transport nutrients and suspended sediment matter (SSM) as well as fresh water from land to coastal regions, where the biological productivity is high. In the coastal area, the buoyancy of fresh water leads to the formation of horizontal anticyclonic gyres and vertical circulations, which affect the variation of biological production such as plankton blooms. However, the primary production caused by the 3-D dynamics have not been quantitatively discussed, and observations can hardly capture the daily temporal variations of phytoplankton blooms. We developed an ocean general circulation model including a simple ecosystem model, to investigate the 3-D and temporal changes in phytoplankton blooms caused by riverine input such as flooding. The distribution patterns of nutrients and phytoplankton differ significantly from that of fresh water. The phytoplankton maxima shift from the downstream (right-hand side of the river mouth) to the upstream regions (left-hand side of the river mouth). The shift that occurs is categorized by the different nitrate origins: (1) river-originated nitrate is dominant in the downstream region; (2) subsurface-originated nitrate is dominant in the upstream region, and is transported by upwelling associated with vertical circulation and horizontal anticyclonic gyre; and (3) regenerated nitrate is dominant in the upstream region. The total primary production in phytoplankton blooms is maintained not only by river-originated nitrate but also by subsurface-originated nitrate that is 1.5 times larger than the river-originated. Several case studies (e.g., including SSM) were conducted in this study.     

椒江河口浮泥的分布和调整

应用光学和声学泥沙剖面监测系统,进行1991、1994和1995年3个航次的椒江河口最大混浊带纵横剖面和时间剖面观测.在受控于潮流和径流对比条件的周期性调整基础上,椒江河口浮泥层还表现出非主流聚集趋向和洼地聚集趋向,促使最大混浊带保持对边界条件十分敏感的泥沙储库.     

Gradients in coral reef communities exposed to muddy river discharge in Pohnpei,Micronesia

This study analyzed how coral communities change along a gradient of increasing exposure to a mud-discharging river in the Enipein Catchment, Pohnpei, Micronesia. Using video transects, we quantified benthic communities at five sites along a gradient moving away from the river mouth towards the barrier reef. The most river-impacted site was characterized by a high accumulation of mud, low coral cover and low coral diversity. Although coral cover leveled off at ∼400 m from the river mouth to values found at the outer-most sites, coral diversity continued to increase with increasing distance, suggesting that the most distant site was still impacted by the river discharges. Fungiidae, Pavona, Acropora, Pachyseris and Porites rus all significantly increased in cover with distance from the river, while Turbinaria decreased. The combined presence and abundance of these six species groups, together with coral species richness, may help to indicate the effects of terrestrial runoff in similar runoff-exposed settings around Micronesia, whereas coral cover is not a sensitive indicator for river impact. Coral reefs are important resources for the people of Pohnpei. To prevent further degradation of this important resource, an integrated watershed approach is needed to control terrestrial activities.     

辽东湾北部浅海区海洋工程地质特征

通过对浅地层剖面仪、侧扫声纳和海底取样等实测资料的详细分析,揭示了辽东湾北部浅海区的自然地质状况和复杂的海洋工程地质特征。该海区海底地形地貌较为复杂,存在海底冲刷深槽、埋藏古河道、浅层气、潮流沙脊与潮沟、埋藏古陡坡、软弱土层及可能的砂土液化层等潜在灾害地质因素,对海上构筑物存在直接或潜在的危险性,应引起高度重视。     

Hydrodynamic modeling and ecohydrological analysis of river inflow effects on Apalachicola Bay,Florida, USA

This paper presents an integrated hydrodynamic modeling and probability analysis approach to assess the long-term effects of changing river inflows on the estuarine ecosystem. The probability analysis method, which is popularly used in advanced hydrological frequency analysis of river flows and rainfalls, has been applied to analyze the effects of changing inflow on salinity and thus on oyster ecology in Apalachicola Bay. Long-term salinity data were predicted through the application of a calibrated 3D hydrodynamic model under two river inflow conditions over a 10-year period. The first flow represents the historic flow. The 2nd flow condition, called Scenario-1, represents a regulated flow scenario to account for the potential increasing upstream water demands. Two stations, Mid Bay and Dry Bar, in the bay were selected to examine the estuarine responses. Under the historic flow condition, the maximum probability salinity at Dry Bar in the rich oyster reef is near 24 ppt, within the optimal salinity range for oyster growth of 16–26 ppt (Harned et al., 1996); the maximum probability salinity at Mid Bay station is 27 ppt, beyond the optimal salinity for oyster growth in mid-bay area where there is no oyster reef around. While it is difficult to examine the difference between two scenarios by conventional time series analysis of river flows and salinity, probability analysis reasonably characterizes and quantifies the changes of river flow and salinity patterns over the 10-year period. The Scenario-1 has caused the increase of the probability in low flows. Higher probability of low flows for the regulated flow scenario shortens the period of optimal salinity in the oyster reef, and cause substantial increase of exceedance probability of higher salinity in the oyster reef to the level beyond the optimal salinity range for oyster growth. The probability analysis approach has demonstrated its advantage for the risk assessments of the long-term estuarine ecohydrological effects under various regulated inflow scenarios to support estuarine water resources managements.     

长江口叶绿素分布特征和营养盐来源数值模拟研究

利用POM(Princeton Ocean Model)模型在长江口及其邻近海域建立了三维斜压动力学模式,该模式开边界处考虑了潮汐、潮流、台湾暖流、沿岸流和长江径流。模式成功地模拟了长江口及其邻近海域的潮汐特征和环流特征。此外2004年11月的实测数据分析结果表明在观测区域的水下河谷西侧位置的强表面羽状锋内,存在着高叶绿素a浓度分布。为了分析长江口外存在的高叶绿素浓度分布和长江口的营养盐输入的相关关系,进行了两次数值试验:(1)给定长江口的径流量和径流输入的营养盐,把长江口的输入作为营养盐输入的惟一源;(2)在开边界处,根据实测资料给定营养盐的输入,同时考虑径流营养盐输入。在(1)、(2)两种情况下,把硝酸盐作为保守物质,进行了平流扩散数值试验。模式的模拟结果和实测资料的对比分析表明:沿岸流、台湾暖流的营养盐输入和上升流从底部输入的营养盐是此高叶绿素浓度区营养盐的重要来源。