Regulation of Navigation Channel on Mouth Bar of Guanhe Estuary     

Li Guochen Associate Professor  Hohai University  Nanjing 《中国海洋工程》1994,(3)

-Based on the feasibility study of developing the navigation resources of the Guanhe River and the model test results of the mouth bar regulation, this paper presents some basic principles for the regulation of the channel on the mouth bar, for instance, the direction of navigation channel should be identical with that of the ebb tide current and the main waves, and perpendicular to the bathymetric contours. The principles for regulating mouth bars are also discussed in this paper.  相似文献   

黄骅电厂取水河段取水特性的数模与物模研究     

童中山  应新亚  钱炳法 《海洋工程》1997,(4)

本文采用数值模拟与物模试验相结合的研究方法，详细地研究了黄骅电厂一、二、三期工程的取水特性。结果表明，现有河道只能满足电厂一期工程的取水需求；若将现有河道进行适当开挖，可以满足电厂三期取水需要。  相似文献   

Influence of Approach Channel on Wave Propagation with Varying Incident Angles     

Zuo Qihua  Yang Zhengji . Senior Engieer  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing 《中国海洋工程》1996,(3)

- The variation of the amplitude of waves with varying incident angles when waves propagate through a typical approach channel is discussed by a numerical calculation method, the result of which shows that the influence of the channel on wave propagation is obvious. When the wave propagation direction is in coincidence with the channel axis, the wave amplitude ratio will decrease with the increase of propagation distance. When the incident angle is 15 - 30 , there appears an area of larger wave amplitude ratio on the side slope facing the waves, but at the another side, the wave amplitude ratio is generally small, indicating that the channel has a shielding effect. When waves propagate across the channel perpendicularly, the wave amplitude ratio can be calculated with the shallow water coefficient.  相似文献   

深圳河河口围垦对防洪和河床冲淤影响研究   总被引：6，自引：0，他引：6  

彭世银 《海洋工程》2002,20(3):103-108

为研究深圳河河口福田保税区围垦填土占用部分河道对深圳河治理工程的影响 ,建立了贴体坐标系下平面二维的深圳河河道 -河口 -海湾整体水域的水流泥沙数学模型 ,计算了不同频率洪峰流量和河口潮位过程组合下河口围垦所造成的深圳河沿程水位抬高程度和河床冲淤变化情况 ,提出了建议的挖除方案  相似文献   

珠江口伶仃洋温度分布特征     

田向平 《热带海洋学报》1994,(1)

依据实测资料，分析了伶汀洋冬、夏季的水温分布特征及其变化。冬季湾内水温的分布和变化较单一，夏季由于河流入海流量增大，河流与海洋水体的相互作用加强，明显可见两个冷、暖水锋在河口湾中段相交，上段为高温的河流淡水控制区，下段为低温的陆架水控制区，两者显著的特点是其控制区内温度变化很小，而在锋面转折地带的河口湾中段，盐淡水混合强烈，其温度变化大，温度等值线呈倾斜分布。  相似文献   

Influence of upwelling and river runoff interaction on phytoplankton assemblages in a Middle Galician Ria and Comparison with northern and southern rias (NW Iberian Peninsula)   总被引：2，自引：2，他引：2  

Manuel Varela  Ricardo Prego  Yolanda Pazos  ngeles Moroo 《Estuarine, Coastal and Shelf Science》2005,64(4):721-737

The first oceanographic research (hydrography, nutrient salts, chlorophyll, primary production and phytoplankton assemblages) in a Middle Galician Ria was carried out in Corme-Laxe during 2001, just a year before the Prestige oil spill, being the only reference to evaluate eventual changes in the phytoplankton community. Due to the small size of this ria (6.5 km²), oceanographic processes were driven by the continental water supplied by Anllons River during the wet season (20–30 m³ s⁻¹ in winter), and the strong oceanic influence from the nearby shelf during the dry season. The annual cycle showed a spring bloom with high levels of chlorophyll (up to 14 μg Chl-a L⁻¹) and primary production (3 g C m⁻² d⁻¹) and a summer upwelling bloom (up to 8 μg Chl-a L⁻¹ and 10 g C m⁻² d⁻¹) where the proximity of the Galician upwelling core (<13.5 °C at sea surface) favors the input of upwelled seawater (up to 9 μM of nitrate and silicate) to the bottom ria layer, even during summer stratification events (primary production around 2 g C m⁻² d⁻¹). Thus, phytoplankton assemblages form a “continuum” from spring to autumn with a predominance of diatoms and overlapping species between consecutive periods; only in autumn dinoflagellates and flagellates characterized the phytoplankton community. In the Middle Rias as Corme-Laxe, the nutrient values, Chl-a, primary production and phytoplankton abundance for productive periods were higher than those reported for the Northern (Ria of A Coruña) and Southern Rias (Ria of Arousa) for year 2001; this suggests the importance of the hydrographic events occurring in the zone of maximum upwelling intensity of the Western Iberian Shelf, where a lack of annual cycles studies exists.  相似文献   

泥石流平面形态的统计分析     

刘希林 《海洋地质与第四纪地质》1995,15(3):93-104

泥石流扇的平面形态可用规划的几何图形来模拟。在研究了中国西南地区小江流域和意大利东北部阿尔卑斯山区的５２个泥石流扇的基础上，本文提出了两种泥石流扇的平面形态：中国西南地区的“等腰三角形＋半圆形”泥石流扇和意大利东北部的“几何扇”。用统计分析建立了两组泥石流扇和泥石流流域之间的形态度量关系。通过两个研究区域的对比，两个流域参数：流域面积和主沟比降确定为影响泥石流扇平面形态和面积的最重要的因素。  相似文献   

Channelled erosion through a marine dump site of dredge spoils at the mouth of the Puyallup River, Washington State, USA     

Neil C. Mitchell   《Marine Geology》2005,220(1-4):131-151

Channels are relatively common on river-mouth deltas, but the process by which they arise from river sediment discharge is unclear because they can potentially be explained either by negatively buoyant (hyperpycnal) flows produced directly from the river outflow or by flows generated by repeated failure and mobilisation of sediment rapidly deposited at the delta front. Channels eroded through a dump site of dredge spoils are described here from multibeam and older sonar data collected in Commencement Bay, at the mouth of the Puyallup River. Shallow channels on the seaward upper surface of the dump site, away from any flows that could have been produced by delta front failures, suggest that at least some hyperpycnal flows were produced directly from the positively buoyant river outflow up to 200 m from the edge of the river mouth platform. The form of channel bed erosion is revealed by the longitudinal shape of the main eroded channel compared with the adjacent dump site profile. It suggests that the channel evolved by its steep front retreating, rather than by simple vertical entrenchment or diffusive-like evolution of the profile, a geometry interpreted as evidence that repeated failure of the bed occurred in response to shear stress imposed by bottom-travelling flows. Model calculations based on shear strengths back-calculated from the geometry of channel wall failures suggest that, if the main channel were eroded solely by hyperpycnal flows, their generation was remarkably efficient in order to create flows vigorous enough to cause channel bed failure. Besides the sediment concentration and discharge characteristics that have been considered to dictate the ability of rivers to produce hyperpycnal flows, it is suggested that the timing of floods with respect to the tidal cycle should also be important because extreme low tides may be needed to ensure that coarse sediment is transferred vigorously to the edge of river mouth platforms.  相似文献   

黄河三角洲河道沉积规律研究Ⅱ. 建林边滩沉积作用机理     

范德江  陈彰榕  栾光忠 《中国海洋大学学报(自然科学版)》2001,31(2):237-242

通过对建林边滩沉积物粒度分布、粒度参数及水体流变性质的分析，阐述了黄河三角洲上河道水流属于牵引流范畴，与低含沙水流无本质上的差别，并探讨沉积物搬运和沉积的基本特征。  相似文献   

减少航道外波浪集聚对策研究   总被引：3，自引：0，他引：3  

李思源  白志刚  王广聚 《海洋技术学报》2002,21(3):56-61

进港航道开挖引起波能重新分布 ,导致航道外近区域波能聚集 ,波高增大 ,从而影响防波堤稳定及港内泊稳条件。文章介绍了 Boussinesq方程的推导过程和发展过程 ,基于深水和缓变地形的色散关系 ,建立了波浪数学模型。该模型可用于研究深水和浅水地区波浪的浅水变形、折射、绕射和反射。并提出了减少波能聚集、降低堤前波高的多种措施。结合大窑湾港实际工程 ,经过多方面的数物模比选 ,利用数学模型优化出一种可行的喇叭口航道开挖方案并付诸实施 ,降低了防波堤的堤前波高 ,满足了预期的设计要求。  相似文献