粤西水东潮汐通道流速不对称性及流速模拟分析

本文分析了广东西部的水东泻湖-潮汐通道不同地段流速的分布持性。指出通道涨落潮流速不对称主要是由于潮水位不对称引起,通道潮流流速过程一方面决定于潮水位的涨落变率,另一方面与泻湖纳潮水域的地形及通道咽喉断面面积随水位变化的特性有关。     

海南清澜潮汐通道的综合治理与航道的合理开发

根据清澜汐通道、泻湖及其沿岸的动力地貌特征,提出该潮汐通道的综合治理及其航道的合理开发４个方面的建议,即保持或扩大泻湖的纳潮量、稳固通道沙咀、稳定岸线以及合理利用通道的周边资源。     

用一维水力学方程求取泻湖水位及潮汐汊道断面流速——以海南陵水新村港为例

本文通过一维水力学运动方程及连续性方程,得出一个反映泻湖水位变化的二阶非线性有阻尼的强迫振动方程,采用龙格-库特四步格式进行求解,并以海南陵水新村港为例,计算了泻湖水位及潮汐汊道的断面流速.研究结果表明:(1)一维水力学方程可容易地求得泻湖-潮汐汊道体系中泻湖内的水位及汊道的断面流速,计算简单快捷.(2)一维水力学方程可分析潮汐汊道体系中的一些基本现象.如潮汐汊道对潮波的"过滤器"特征;由于泻湖-潮汐汊道体系的阻尼系数较大所导致的潮波自外向泻湖传播时衰减剧烈;径流对泻湖水位及汊道流速产生有利于落潮优势的影响;风可使泻湖水位抬升或下降等.(3)无论是否考虑泻湖与潮汐汊道面积随水位的变化,一维水力学方程都具有相当大的缺陷.由于其不能反映泻湖内地形的空间变化,也不能解决漫滩与归槽等过程,在外海潮波无次生波的情况下,它本身不能产生次生潮波,因而不能正确地反映潮汐汊道体系的涨落潮历时与流速不对称,从而不能分析泥沙的净输运及潮汐汊道的稳定性问题.(4)新村港泻湖-潮汐汊道体系中潮汐汊道的断面面积大小对整个体系的稳定性及演变趋势起着控制作用.     

沙坝—泻湖海岸动力地貌学研究进展

国内外对沙坝－泻湖海岸的研究主要采取动力地貌学的方法，本文评述了近一个半世纪以来在这一领域所取得的重要成果。波浪、潮汐、径流等特殊的动力场决定了泥沙输运的方式和路径，从而形成了与其相应的沙坝、泻湖、潮汐通道三大地貌体系。     

粤西水东湾潮汐通道—落潮三角洲的动力地貌过程

本文论述了广东省水东沙坝泻湖海岸体系中潮汐通道和落潮三角洲的动力地貌过程,包括通道的潮汐与波浪动力特点、落潮三角洲区域动力与泥沙运动、拦门沙成因及落潮三角洲近期冲淤动态等,最后对通道稳定性和拦门沙开挖可能性进行讨论,认为该通道稳定性好,拦门沙只要采取深挖措施且开挖方向较合理,有可能取得成效。     

海南岛周边泻湖资源保护与可持续利用研究探讨

基于海南岛泻湖分布众多、泻湖资源丰富,目前大部分泻湖处于退化状态,且未见有相关文献对海南岛泻湖资源进行详细系统的介绍与总结,本文通过对海南东寨港、东水港、花场湾、清澜港、小海、老爷海、博鳌泻湖、三亚河、青梅港、黎安港、新村港、铁炉港及新英湾等泻湖的地理分布、面积、资源类型等方面进行描述,从人类活动、陆源污染、海洋工程及自然演变等因素对泻湖的影响进行了分析,阐述了泻湖目前所面临的威胁及破坏,提出了对泻湖进行整治规划、持续开发利用、加强法制监督及提高民众泻湖资源保护意识等方面的保护与可持续利用建议,为海南岛泻湖资源的保护与可持续利用提供基础数据与理论参考。     

潟湖潮汐通道水力特性与治理

综合论述了潟湖潮汐通道口门之流速、断面面积、通道长度、延时角和饱满系数之间的关系,以及沿岸漂沙对口门的影响。对不同类型的潟湖潮汐通道,提出了中潮位射流导流堤、口门复式断面和通道分汊等治理方法及其通道口门相关尺度的具体计算。     

海南岛小海沙坝-泻湖-潮汐通道体系自动调整及恶化

本文运用历史地图对比方法，结合现场考察及水文泥沙测量资料，分析海南岛小海口门近40a来的变化过程，找出小海口门在人为作用下的演变规律．结果表明，小海沙坝—泻湖—潮汐通道体系曾是一个稳定的系统，它通过口门断面、地形调整以适应在人类活动作用下口门动力的变化并保持相对平衡．三大人为活动的综合影响，尤其是盐墩三岛的围垦及冈箱养殖，破坏了口门维持的最后动力(潮汐动力)，使小海沙坝—泻湖—潮汐通道体系失去了调整作用，直接导致了口门的迅速缩小．因此小海综合治理的首要任务是小海口门的治理。     

黄河河口莱州湾人工潟湖的设计和功能

在简要概述潟湖基本概念和特征的基础上,围绕黄河河口莱州湾人工潟湖工程的布局方案进行了初步设计。初步设计的莱州湾人工潟湖属于半封闭型海岸潟湖,涉及海岸线长度约35km,海域面积470km2,主要由入海水沙通道、人工沙坝、潮汐通道三大工程体系组成。分析指出:人工潟湖将具有优化黄河入海水沙分配格局、减轻河口防洪防凌防潮压力、改善和维护海岸带生态环境、发展水产养殖、丰富旅游资源等多项功能。本文从施工技术、维护技术两个方面论证分析了人工潟湖的可行性,最后提出了兴建人工潟湖需要解决的诸多关键技术问题,如入海水沙通道的设计标准、补水分洪时机和规模、潮汐通道的设置及其纳潮数量、潟湖形成后泥沙输移与沉积及其容沙能力、对周围海域环境及其滨海生物的影响效应等问题等。     

芝罘连岛沙坝北端封闭泻湖成因与发育过程

芝罘连岛沙坝北端泻湖是６０００ａ Ｂ．Ｐ．以来海平面变化过程中的产物，其形成受海平面变化，气候变化，海岸古环境与近岸物质迁移的影响，泻湖附近地貌发育经历了水下沙嘴，砾石堤发育，封闭泻湖形成４个阶段。     

海南新村潟湖潮汐、潮流特征及其对营养盐的影响

基于海南新村潟湖2020年12月水文和水质多要素实测数据,研究了该海域的潮汐、潮流变化特征,并探讨了潮位变化对潟湖营养盐的影响。结果表明,新村潟湖的潮汐为不规则全日潮,潟湖口门处的潮流为往复流,涨潮历时15 h,落潮历时10 h。大、小潮期间3个观测站点溶解性无机氮(DIN)浓度变化范围为0.91~20.87 μmol/L,磷酸盐(PO3-4)浓度变化范围为0.11~5.92 μmol/L,硅酸盐(SiO2-3)浓度变化范围为2.36~134.75 μmol/L。大、小潮期间,潟湖内3个观测站点DIN、PO3-4、SiO2-3浓度随着涨、落潮过程发生变化。潟湖口门处流速对观测站点潮位变化有着重要的影响,潮通量基本决定了潮位的变化。潟湖口门处和渔排密集区域的营养盐浓度与潮位呈现显著的负相关关系,潮流流速对口门处和渔排密集区域的营养盐变化有着重要影响。该研究结果将为新村潟湖的污染治理及生态修复提供科学依据。     

Mean water level setup/setdown in the inlet-lagoon system induced by tidal action-a case study of Xincun Inlet, Hainan Island in China

With the tides propagating from the open sea to the lagoon, the mean water level （MWL） in the inlet and lagoon becomes different from that at the open sea, and a setup/setdown is generated. The change of MWL （setup/setdown） in the system imposes a great impact on regulating the development of tidal marshes, on determining the long-term water level for harbor maintenance, on the planning for the water front development with the flood control for the possible inundation, and on the interpretation of the historical sea level change when using tidal marsh peat deposits in the lagoon as the indicator for open sea＇ s sea level. In this case study on the mechanisms which control the setup/setdown in Xincun Inlet, Hainan in China, the 2-D barotropic mode of Eulerian - Lagrangian CIRCulation （ELCIRC） model was utilized. After model calibration and verification, a series of numerical experiments were conducted to examine the effects of bottom friction and advection terms, wetting and drying of intertidal areas, bathymetry and boundary conditions on the setup/setdown in the system. The modeling results show that setup occurs over the inlet and lagoon areas with an order of one tenth of the tide range at the entrance. The larger the bottom friction is, a larger setup is generated. Without the advection term, the setup is reduced clue to a decrease of water level gradient to compensate for the disappearance of the advection term. Even without overtides, a setup can still be developed in the system. Sea level rise and dredging in the inlet and tidal channel can cause a decrease of setup in the system, whereas shoaling of the system can increase the setup. The uniqueness of the Xincun Inlet with respect to MWL change is that there is no evident setdown in the inlet, which can be attributed to the complex geometry and bathymetry associated with the inlet system.     

山东乳山市白沙滩沙坝泻湖沉积体系

根据实际观测和勘测资料,介绍和总结了白沙滩沙坝、泻湖、潮流通道和外潮流三角洲等地貌单元的沉积特征和演化机理,分析了它们之间的依存演化关系.白沙滩沙坝是由全新世不同时期3条沙嘴拼贴而成的,沙坝发育导致泻湖出现.当沙坝扩展时泻湖水面缩小,当泻湖扩展时沙坝变窄,在沙坝泻湖交接地带二者呈犬牙交错关系.潮流通道增强直接影响潮流三...     

Residence times in a hypersaline lagoon: Using salinity as a tracer

Generally the waters of the Ria Formosa Lagoon, Portugal have a short residence time, in the order of 0.5 days (Tett, P., Gilpin, L., Svendsen, H., Erlandsson, C.P., Larsson, U., Kratzer, S., Fouilland, E., Janzen, C., Lee, J., Grenz, C., Newton, A., Ferreira, J.G., Fernandes, T., Scory, S., 2003. Eutrophication and some European waters of restricted exchange. Continental Shelf Research 23, 1635–1671). This estimation is based on the measurements of currents and the modelling of water exchange at the outlets to the ocean. However, observations of the temperature and salinity in the inner channels imply that residence time is greater in these regions of the lagoon. To resolve this apparent contradiction, spatial measurements of the temperature and salinity were made with a meter for conductivity, temperature and depth along the principal channels of the western portion of the lagoon, with a sampling frequency of two per second. Evaporation rates of 5.4 mm day⁻¹ were measured in a salt extraction pond adjacent to the lagoon and used to determine the residence time through salinity differences with the incoming seawater. In June 2004, the water flooding in from the ocean had an average salinity of 36.07 which contrasted with a maximum of 37.82 at mid ebb on a spring tide, corresponding to a residence time of >7 days; the mean residence time was 2.4 days. As the tide flooded into the channels, the existing water was advected back into the lagoon. Although there was a small amount of mixing with water from another inlet, the water body from the inner lagoon essentially remained distinct with respect to temperature and salinity characteristics. The residence time of the water was further prolonged at the junction between the main channels, where distinct boundaries were observed between the different water masses. As the water ebbed out, the shallow Western Channel was essentially isolated from the rest of the outer lagoon, and the water from this channel was forced down the Ramalhete Channel, from where it was unable to exit the lagoon in one tidal cycle due to the extensive path length of ∼14 km to the sea.     

Hydrological characterisation of Ria de Aveiro,Portugal, in early summer

The hydrological features of Ria de Aveiro, a coastal lagoon on the northwest Atlantic coast of Portugal, were investigated in two sampling surveys carried out between 3/6 and 24/6/97 and between 29/6 and 7/7/97, respectively. There was a significant freshwater inflow into the lagoon during the first survey, especially in the first days, due to the recent rainfalls. Records concerning water level, salinity, temperature and current velocity were performed at several stations located along the four main channels of the lagoon. The type of tide at the mouth was determined and was observed that astronomical tide is the main forcing agent driving water circulation in Ria de Aveiro. The tide at the mouth is semidiurnal and the tidal wave propagation in the lagoon has the characteristics of a damped progressive wave. Typical estuarine longitudinal salinity and temperature gradients connected with the distance to the mouth were identified, whereas vertical and transverse gradients were found unimportant, except in the frontal zone between oceanic and fresh water masses. According to the results, even though Ria de Aveiro should be considered as vertically homogeneous, some channels may reveal characteristics of a partially mixed estuary, depending on the freshwater input.     

海南岛东海岸小海澙湖水文基本特征

小海是位于海南岛东海岸的一个典型湖。通过对小海湖的水文调查研究，较系统地掌握了湖潮汐、潮流、余流、盐度和泥沙的特征。湖水深虽小，但在口门一带的盐度分布及表、底层流流速、流向的差别却较大，存在类似入海河口的缓混合及纵向环流的现象。     

The effects of the reed,Phragmites australis (Trin.), on substratum grain-size distribution in a salt marsh

The effects of the reed,Phragmites australis (Trin.), growing in a brackish water lagoon, were studied in relation to the grain-size distribution of the substratum. At the salt marshes near the lagoon, the upper soils from the surface to a depth of 20 cm contained much silt-clay. These fine particles were found to be transferred from the river and fish ponds near the lagoon, and to be deposited when the tidal rhythm changed, that is, when the water current stopped. In addition, the fine particles, which were deposited on the bottom of the lagoon adjacent to the marshes, became resuspended as a result of wind-caused wave action, and then were transported and redeposited in the salt marshes at the flood tide. Since the reeds further reduced the water current caused by the waves and tide, the reeds were thought to promote redeposition of the resuspended matter. In other words, the reeds were considered to protect deposited and redeposited particles such as silt and clay from resuspension as a result of wave action by reducing the effects of waves and wind. These processes suggested that silt-clay will become abundant in the substratum of the salt marsh adjacent to the lagoon.     

Atoll lagoon flushing forced by waves

Water level and current measurements from two virtually enclosed South Pacific atolls, Manihiki and Rakahanga, support a new lagoon flushing mechanism which is driven by waves and modulated by the ocean tide for virtually enclosed atolls. This is evident because the lagoon water level remains above the ocean at all tidal phases (i.e., ruling out tidal flushing) and because the average lagoon water level rises significantly during periods with large waves. Hence, we develop a model by which the lagoons are flushed by waves pumping of ocean water into the lagoon and gravity draining water from the lagoon over the reef rim. That is, the waves on the exposed side push water into the lagoon during most of the tidal cycle while water leaves the lagoon on the protected side for most of the tidal cycle. This wave-driven through flow flushing is shown to be more efficient than alternating tidal flushing with respect to water renewal. Improved water quality should therefore be sought through enhancement of the natural wave pumping rather than by blasting deep channels which would change the system to an alternating tide-driven one.     

白沙口海岸小泻湖的演变及砂坝泻湖海岸的成因

砂坝泻湖海岸约占世界海岸线总长度的11%,它伴有巨大的堆积体,成为某些沉积矿床发育的有利条件。因此,对于砂坝泻湖海岸的研究,不但与研究海岸演化、新构造运动等理论问题关系密切,而且对海岸工程、寻找砂矿等方面也有重要意义。许多学者都讨论过砂坝泻湖海岸的形成问题,但至今各家观点尚未     

Long-term morphological modeling of a tidal inlet: the Arcachon Basin,France

The Arcachon Lagoon on the French Atlantic coast is a triangular shaped lagoon of 20 km on a side connected to the ocean by a 3-km wide inlet between the mainland and an elongated sand spit. This tidal inlet exhibits a particularly active morphology due to locally strong tidal currents and rough wave conditions. During the past 300 years, minimum and maximum spatial extents of the Cap Ferret sand spit have varied by 8 km while one or two channels have alternately allowed circulation between the lagoon and the ocean. These impressive morphological changes have never prevented regular flushing of the lagoon, eventhough the spit came as close as 300 m from the coast during the 18th century. According to Bruun's concept of tidal inlet stability [Theory and Engineering (1978), 510 pp.], the balance between longshore littoral transport and the tidal prism ensures the perpetuity of the inlet.Process modeling was believed to give better insight into the respective roles of tides and waves in driving the long-term morphological changes of the inlet. A two-dimensional horizontal morphodynamic model was therefore developed, combining modules for hydrodynamics, waves, sediment transport and bathymetry updates. The use of process models at a scale of decades requires a schematization of the input conditions. We defined representative mean annual wave and tide conditions with respect to sediment transport, i.e. conditions that induce the same annual transport as measured in the field. Driven by these representative conditions, simulations run from the 1993 bathymetry show that the tide is responsible for the opening of a new channel at the extremity of the sand spit (where tidal currents are the strongest), while waves induce a littoral transport responsible for the longshore drift of sand bodies across the inlet. One particular simulation consisted in running the model from a hypothetical initial topography where the channels are filled with sand and the entire inlet is set to a constant depth (3 m). The results show the reproduction of a channel and bar system comparable to historical observations, which supports the idea that the lagoon is unlikely to be disconnected from the ocean, provided tide and wave conditions remain fairly constant in the following decades.