新洋港闸下港道淤积分析及对策

由于挡潮闸的修建,改变了河口地区的水动力条件,使潮位和潮流过程出现位差,破坏了原有天然情况下的泥沙冲淤平衡,闸下港道受径流、潮流、潮汐、风浪和围垦等多种因素的共同影响,闸下港道回淤迅速,淤积严重,河槽萎缩,排水不畅,影响了工程排涝效益的充分发挥。本文通过对新洋港闸下港道淤积特性、目前港道状况及淤积原因和防淤减淤措施的分析,提出了减少港道淤积的建议。     

延安市南沟门水库泥沙淤积运行方式研究

本文以南沟门水库及马家河引水工程的长系列水沙资料为基础,建立一维恒定不平衡输沙数学模型,对位于葫芦河上的南沟门水库进行泥沙淤积运行方式的分析与研究,研究结果表明：该水库泥沙淤积形态为三角洲淤积,淤积平衡年限为50年左右,并得出了南沟门水库60年间不同年限的淤积量、冲淤趋势及淤积库容曲线,为工程设计提供不同年限的淤积高程、淤积库容等基础参数,为研究多泥沙河流上的水库工程,提供有益的帮助与借鉴.     

湖州市区东西苕溪河道淤积成因分析及对策

东西苕溪防洪工程是治太(治理太湖)骨干工程之一,包括导流港拓浚及东大堤加高加固、旄儿港二期拓浚、长兜港二期拓浚等10个子项目,主体工程于1998年12月开工,2007年5月完建,在历次防洪中发挥了巨大的工程效益。经过多年的运行,河道淤积情况越来越严重,直接影响了苕溪洪水下泄入太湖的能力,给洪水调度带来了难度。现以2011—2013年的河道淤积实测资料及沿程石矿尾砂排放监测、调查数据资料为基础,定量分析河道淤积总量及成因,探讨河道综合治理的措施与对策。     

用γ—射线回淤仪定点观测镇江港港池淤积变化过程

本文简要叙述了γ-透射法回淤仪的结构,测量原理,室内外试验情况,并概括地介绍用γ-回淤仪在镇江港港池进行定点回淤观测中所取得的资料和港池淤积与含沙量、潮位、流速的初步关系.本次测量仪器测淤厚度为45cm,测量精度为0.32mm.试验结果表明,该项测试技术是研究港口、航道泥沙淤积规律的一种有效的测量手段.     

里下河地区沿海主要港道冲淤规律及影响要素探析

为探寻江苏省里下河地区主要排涝入海通道射阳河、黄沙港、新洋港、斗龙港等闸的下游港道在近几年工情发生变化后的冲淤规律,利用2008年至2013年4月港道监测以及排水量资料分析得出,在非汛期,除射阳河外,黄沙港、新洋港、斗龙港等3条港道的淤积量与排水量、阶段平均排水流量高度相关;在汛期,射阳河等4条港道冲淤量、单位水量冲淤量与河床容积明显相关;得到各港道基本维持冲淤平衡或冲刷的阶段平均排水流量,并提出将阶段平均流量与淤积量的乘积作为易淤指标,以判断不同港道淤积特性。分析成果为改进四大港闸调水冲淤运行、尽可能减轻淤积提供技术依据。     

江苏沿海地区河道淤积典型性分析

通过实测潮水位、流量、含沙量、冲淤水量、河道淤积量等水文资料,分析、判断河道淤积的基本特征、影响因素,时段泥沙淤积量、引江冲淤效果、港道淤积年际变化。     

基于SWAN和ECOMSED模式的大风作用下黄骅港波浪、潮流、泥沙的三维数值模拟

根据黄骅港外航道淤积问题的具体情况,本文采用三维细颗粒泥沙的ECOMSED模式对黄骅港海域的潮流、泥沙进行了模拟。数值计算结果与潮流为主要动力条件的现场实测结果进行了比较,二者吻合较好。在此基础上,本文采用SWAN风浪模型和ECOMSED对黄骅港骤淤进行了数值模拟,并与收集到的现场实测资料进行比较,也得到较好的结果。数值模拟显示,波浪是造成黄骅港外航道泥沙淤积的主要动力因素;在以波浪为主的动力条件下,含沙量在波浪破碎带达到最大,并且沿水深变化梯度较大。破碎带当地的泥沙跨过航道落淤是黄骅港外航道淤积的主要原因,岸边泥沙随落潮流下泻不是黄骅港外航道大风骤淤的主要原因。     

里下河沿海“四港”闸下港道水力冲淤措施的采用

射阳河、新洋港、黄沙港、斗龙港统称"四港",是苏北里下河地区排水入海的主要通道.自20世纪50年代"四港"陆续建闸后,改变了潮水大进大出的自然状态,加之地处淤长型海岸,闸下港道淤积严重,并呈逐年增长态势.     

高栏港淤积机理探讨

根据高栏港近几年的实测资料及已有的研究成果,在分析该区动力特性及输沙特征的基础上,对该区回淤状况进行了研究,试图探求其淤积机理,并结合骤淤分析,建立大风天航道回淤估算公式.     

淤长型海岸闸下港道维护中的机船拖淤技术

江苏省盐城市射阳河、黄沙港、新洋港、斗龙港等“四港”闸下港道淤积状况日益加剧,但与该市同处淤长型海岸的其他挡潮闸闸下港道相比,没有出现因淤积“港死闸废”问题,一直保持着基本的通畅条件,并在抗御1991年、1998年、2003年、2006年、2007年特大涝灾中发挥了重大作用。这得益于利用专门而独有的机船拖淤技术长期实施港道经常性维护作业,疏浚河槽、拓宽河床、切除边滩。     

太湖长兜港固体悬浮物再悬浮的室内模拟

定量研究浅水湖泊动力扰动与沉积物再悬浮的关系,目前仍是湖泊研究中的难点之一。实验利用再悬浮发生装置,对太湖长兜港沉积物风浪扰动进行室内模拟,建立扰动强度与有效波高之间的关系,定量分析风浪对太湖水体中悬浮物的影响及固体悬浮物在水体中的垂向分布,初步得出风浪对太湖沉积物扰动深度一般在毫米级的结论。     

长江口北支涌潮的形成条件及其初生地探讨

根据2001年4月青龙港出现涌潮时的实测流速和水深，采用水跃原理，简明地揭示了涨潮流速大于潮波传速是北支涌潮的成因。通过影响流速和波速的因素分析，并经实例计算认为：北支的喇叭形河势和水下沙坎是涌潮形成的必要条件；青龙港一潮的进潮量达到1.5亿m3，或北支口门一潮进潮量达到18亿m3是涌潮形成的充分条件。进而据沿程水深和潮汐等有关资料，经对比、试算，建立了沿程变化的进潮量、潮差等计算公式，并计算得到：在口门最大进潮量20.7亿m3的条件下，也只有当潮波上溯到距离口门约50km的灵甸港时，才出现流速大于波速，初生涌潮。由此表明，灵甸港是现今北支涌潮的初生地。     

Dynamics of Reproduction by Hatchery Lake Trout on a Man - Made Spawning Reef

Reproduction by hatchery lake trout, critical for rehabilitation of lake trout stocks in the Great Lakes, had not been previously described and measured. Reproduction by hatchery lake trout on a man-made spawning reef in Presque Isle Harbor, Lake Superior, in 1977-80 was qualitatively and quantitatively described using gill nets, egg traps, and fry traps. Scuba divers measured physical parameters of the reef. Lake trout spawned during a 15- to 28-day period between 12 October and 14 November mainly during 1800–2000 hours. The Petersen single census was a better method of estimating adults than either multiple-census or fecundity-egg deposition methods. The Petersen estimate of adults was nearly 4,000 males and 1,900 females in 1979. Egg deposition and swim-up fry production ranged from 122 to 518/m² and 20 to 46/m², respectively. Substrate on the man-made reef was a 27- to 42-cm thick layer of granite and limestone cobbles 6 to 20 cm in diameter. Spawning behavior and quantitative aspects of reproduction by hatchery lake trout were similar to that previously reported for native lake trout in the Great lakes and elsewhere. Man-made reefs may be a valuable lake trout management tool.     

基于GIS的长江口北港冲淤演变及河道特征可视化分析

以1964 2002年多幅不同年代的长江口北 港海图为基础资料,利用GIS和DEM相结合的方法,并借助于三维河道冲淤演变立体图和冲淤 量数据,分析了北港的冲淤演变和河道特征演变。结果表明：1964 2002年,北 港河段整体表现为冲刷,泥沙冲刷量为3.775亿t;在38年里北港河道的断面形态经历了 从两槽一脊向三槽两脊以及三沙四沟的复杂演变。研究方法可在今后河势分析、河道整治研究中加以应用。     

Food of Young-of-the-Year Lake Trout (Salvelinus Namaycush) in Presque Isle Harbor,Lake Superior

The food habits of young lake trout (Salvelinus namaycush) were studied by examining the digestive tracts of 293 young-of-the-year collected in Presque Isle Harbor, Lake Superior. Lake trout in the 25 to 27-mm length range started to eat food organisms before all of their yolk material was absorbed. Organisms consumed by the 25 to 27-mm young-of-the-year included Chironomidae, Copepoda (Harpacticoida, Calanoida, Cyclopoida), and Cladocerea (Daphnia spp., Bosmina sp., Chydorus sp.). Chironomid pupae and chironomid larvae accounted for 74% and 5%, respectively, of the total volume of food eaten by the young lake trout in Presque Isle Harbor. Although copepods, cladocerans, and mysids were present in many stomachs, their contribution to the total volume of food was only 15%. Some lake trout in the 32 to 54-mm length range had consumed fry of sculpin (Cottus spp.) or rainbow smelt (Osmerus mordax), but the overall contribution of fish fry to the total volume of food was only 4% (frequency of occurrence, 10%). The lake trout in Presque Isle Harbor fed heavily on planktonic organisms, sparingly on benthic organisms, and were opportunistic feeders that appeared to prey on whatever forage organisms were available in the shallow nearshore waters.     

Lagrangian analysis of the transport and processing of agricultural runoff in the lower Maumee River and Maumee Bay

Lagrangian analyses is used to evaluate the processing of nutrients and sediments during storm runoff events as water moved from the Maumee River loading station at Waterville, OH through the lower river, Maumee Bay and into Lake Erie's western basin. Chemical signatures of storm water at Waterville were used in combination with frequent collections of water at transects along the flow paths to evaluate processing. These signatures consisted of the contrasting chemographs of conservative parameters (chloride and sulfate), dissolved nutrients (dissolved reactive phosphorus (DRP) and nitrate) and particulate substances (suspended solids (SS) and particulate phosphorus (PP)). During low flow, sharp drops in concentrations of chloride and sulfate indicated that mixing zones between river water and bay/lake water occurred at the river mouth. During high flows, the location of the mixing zone between riverine and bay/lake water was indicated by the margin of storm-event sediment plumes, with larger storms extending further into the lake. Steep concentration gradients of DRP and nitrate between high storm water concentrations and low bay/lake water concentrations were also present at the plume margin. The large areas of storm water inside the plume margin contained high DRP and nitrate concentrations but relatively low SS and PP concentrations, due to SS and PP deposition along the flow paths. Because this deposition occurred in water with high DRP concentrations, little of the bioavailable PP was likely to have been released prior to deposition. This storm runoff water provides excellent media for algal growth.     

黄河河口潮流和泥沙淤积过程数值分析研究

用有限元方法对黄河河口海域的潮流海洋动力过程进行了数值模拟和分析；通过对典型时刻河口潮流流速矢量图和流速等值线分布图的分析计算，验证了黄河河口门外以及渤海湾和莱州湾交界点存在的两个高流速场；通过入海泥沙淤积厚度等值线平面分布及其变化过程、淤积厚度沿入海流路纵向的变化过程和海底典型高等线+1m，0m和-1m变化过程对河口海岸冲淤、海底变形过程进行了动态跟踪模拟和分析，所得结果与实测资料和遥感解译图像分析基本一致。     

On the Assessment of Atmospheric Deposition of Sulfur and Nitrogen Species to the Surface of Large Inland Lakes—Lake Champlain

Early work indicated that wet deposition of radioactive fallout to the water surface of a lake greatly exceeded dry, when calculated as annual averages. To test whether this result also applies to the deposition rates of soluble trace gases from the lower atmosphere, data collected at land sites near Lake Champlain have been used to estimate deposition rates to the lake itself, using an analysis of the wind speed-up factor as an intermediate step. The contribution of dry deposition of the major nitrogen and sulfur chemical species is estimated to have been less than 20% of the total atmospheric deposition. However, this result must not be extrapolated to the watershed in which Lake Champlain resides, since evidence obtained elsewhere indicates that the dry deposition contribution over the entire watershed will likely be similar to the wet. The analysis indicates that for the period from 1992 to 1997 the annual total deposition rates of oxidized nitrogen and sulfur ranged from 300 to 500 tonnes per year and 600 to 1,100 tonnes per year, respectively.     

Effects of Hydrological Flow Regime on Sediment-water Interface and Water Column Nitrogen Dynamics in a Great Lakes Coastal Wetland (Old Woman Creek,Lake Erie)

Sediment-water interface nitrogen (N) transformations and water column ammonium cycling rates were measured along a stream to lake gradient at three sites within Old Woman Creek (OWC) and one near-shore Lake Erie site during two hydrological regimes: one with open flow to the lake after a rain event (July 2003), and another with a sand barrier blocking flow (July 2004). Net N2 effluxes in OWC at all times and at the near-shore Lake Erie site in July 2003 suggest that sediments are a N sink via denitrification. Observed dissimilatory nitrate reduction to ammonium (DNRA) may counteract some of this N removal, particularly when the creek mouth is closed. Upstream, a closed creek mouth led to higher sediment oxygen demand, net N₂ flux, potential DNRA, and potential denitrification rates. The lake site exhibited lower rates of these processes with the creek mouth closed except denitrification potential, which was unchanged. Denitrification in OWC appeared to drive N limitation in the lower wetland when the sand barrier was blocking flow to the lake. Higher potential versus in situ denitrification estimates imply that water column NO₃⁻ limits and drives denitrification in OWC. Water column to sediment regeneration ratios suggest that sediment recycling may drive primary production in the OWC interior when the creek mouth is closed and new N inputs from runoff are absent, but more data are needed to confirm these apparent trends. Overall, hydrological regime in OWC appeared to have a greater impact on sediment N processes than on water column cycling.     

Phytoplankton Composition,Abundance, and Distribution: Nearshore Lake Ontario and Oswego River and Harbor

Phytoplankton samples were collected during July, August, and October of 1981 from 16 stations located in the nearshore of Lake Ontario and in the Oswego Harbor and river. Phytoplankton assemblages observed represented many species widely recognized as associated with eutrophic environments and environments possessing high chloride levels. Picoplankton and diatoms were the dominant groups on a numerical and bioyolume basis, respectively. The eutrophic species Stephanodicus tenuis, Fragilaria capucina, and Scenedesmus spp. were present in the Oswego Harbor and river with substantially higher abundances than in the nearshore region of Lake Ontario. A decrease in abundance of the historically prevalent Asterionella and Tabellaria and an increase in cryptomonads is suggested for the Oswego area. Halophilic species dominated the diatom assemblage of the Oswego Harbor and mouth of the Oswego River. The abundance of halophilic species was correlated with high conductivity and chloride levels. Cyclotella atomus, Cyclotella cryptica, and Cyclotella meneghiniana, the dominant halophilic species at the harbor and river stations, accounted for 36.6% of the total diatom abundance.