Influence of the Three Gorges Project on saltwater intrusion in the Yangtze River Estuary

The Three Gorges Project (TGP) is a transcentury project that has aroused world attention. It is expected that the flow velocity and runoff of the Yangtze River will be changed after the project has been accomplished. Consequently, however, the ecological environment in the Yangtze River Basin, particularly in the estuary region, will be affected. Salinity intrusion into the Yangtze River estuary, in general, is mostly affected by the Yangtze River discharge and its external tidal level. This paper focuses on examining the influence of changes in runoff on salinity value. The question, to which should be paid attention is: how is the interaction between changes in runoff of the Yangtze River and salinity distribution in the Yangtze River estuary, China? In this research, a three-dimensional model has been used to identify the effects of runoff change on salinity distribution. The drawn conclusion is that the change of salinity is influenced by discharge variation. Positive and negative impacts of TGP would both turn up but in different period. In sum, TGP is in favor of restraining saltwater intrusion. Nevertheless a suitable method should be found to resolve its negative influences.     

长江口咸潮入侵扩散响应函数及初步应用

咸潮入侵是入海径流和潮汐共同作用的盐度扩散过程。以量能累积与阻抗交互作用过程为理论基础,采用逻辑推理和数学分析推导了入海流量、潮差和咸潮入侵面积三者扩散响应的函数关系和曲线型态,并利用长江口近50年枯季入海流量、潮差和咸潮入侵面积进行了实证分析。结果表明,在一定入海流量条件下潮差与咸潮入侵面积关系具有S型曲线特征,入海流量与咸潮入侵最大面积关系也具有S型曲线特征,共同构成一个三维咸潮入侵扩散响应函数;长江口近50年的实测数据实证了上述三维关系特征,据此构建了双曲正切的S型长江口咸潮入侵扩散响应函数,并阐述了参数定值与量化方法;以此函数为基础,分析确定了长江口入海流量大于10 000 m3/s时可抵御大规模咸潮入侵,同时计算了2001-2012年咸潮入侵损失。     

基于反射光谱的珠江口咸潮遥感方法

为监测珠江口河网区水体的盐度变化,基于同步测量的水体黄色物质、盐度和水体表面光谱数据,利用MATLAB分析了水体光谱反射率和黄色物质浓度之间的关系。结果表明:在磨刀门水道,反射率与黄色物质在400nm处的吸收系数g₄₀₀有较好关系,在R₇₀₄/R₅₁₃处,R²=0.70;在虎门水道,g₄₀₀与反射率比值R₇₀₃/R₄₈₈之间也有较强的负相关,R²=0.58。同样,又分析了磨刀门和虎门水道黄色物质吸收系数与表面盐度的关系,都发现了较好的相关性,R²>0.67。根据以上分析,得到了一种珠江口河网区水体表面盐度监测的新方法,并采用中等分辨率成像光谱仪(MERIS)的模拟数据来进行模型验证,结果表明利用MERIS数据对珠江口河网区咸潮进行监测是可行的(均方根误差小于0.308%)。     

Effect of saltwater intrusion on groundwater environment in Weihe River downstream,Shandong Province,China

Based on the geological and hydrogeological conditions along with dynamic changes of groundwater level, this paper analyzes the hydrodynamic characteristics of saltwater intrusion in the study area. According to monitoring data of groundwater quality, the distribution characteristics of macro component are analyzed, and then fuzzy comprehensive evaluation method is adopted to evaluate the impact of saltwater intrusion on groundwater environment. Concerning the influence degree of groundwater environment, the study area is divided into brine area, seriously influenced area, moderately influenced zone, slightly influenced zone and uninfluenced zone. The results can offer references for prevention and control of saltwater intrusion as well as the protection of water resources.     

Effect of saltwater intrusion on groundwater environment in Weihe River downstream,Shandong Province,China

Based on the geological and hydrogeological conditions along with dynamic changes of groundwater level,this paper analyzes the hydrodynamic characteristics of saltwater intrusion in the study area.According to monitoring data of groundwater quality,the distribution characteristics of macro component are analyzed,and then fuzzy comprehensive evaluation method is adopted to evaluate the impact of saltwater intrusion on groundwater environment.Concerning the influence degree of groundwater environment,the study area is divided into brine area,seriously influenced area,moderately influenced zone,slightly influenced zone and uninfluenced zone.The results can offer references for prevention and control of saltwater intrusion as well as the protection of water resources.     

Environmental hazard from saltwater intrusion in the Laizhou Gulf,Shandong Province of China

Coastal areas play an important role in the socioeconomic development of the coastal zones based on the different land uses. These regions are vulnerable to hydrogeological hazards and are seriously affected by coastal erosion, saltwater intrusion in the phreatic aquifer, and sea level rise, which are worsened by human action, thereby increasing the risk of land degradation in the coastal regions. Saltwater intrusion in the Laizhou Gulf located in northern part of Shandong Province of China was the main natural hazard. Manmade interventions and actions (i.e., exploitation of aquifers without adequate knowledge of the hydrology setting and an adequate management program) worsen this natural hazard. Irrational human activity induces environmental hazard to the overall coastal areas.     

长江口北支倒灌影响区盐度预测经验模型

为预测不同径流过程影响下的盐水入侵强度,以长江口南支上段为研究对象,采用实测资料和理论分析相结合,建立了以大通流量和农历日期快速估算氯度值的经验模型。首先,以徐六泾实测潮位资料结合调和分析理论,在考虑11个主要分潮情况下证明日均潮差为半月周期函数,提出了用农历日期估算日均潮差的方法;其次,采用东风西沙实测氯度资料,选用不同函数形式,分析了以支汊盐水倒灌为主的情况下日均氯度对径流、潮差的量化响应关系;最后,提出了指数函数形式的氯度预测经验模型,模型计算值与实测值之间的决定系数在0.8以上。提出的经验模型可由大通流量快速估算特定位置的盐度,为相关的工程和规划研究提供了便捷途径。     

磨刀门水道咸潮上溯动力特性分析

为研究磨刀门水道咸潮上溯的动力特性,基于非结构网格海洋模型（Finite Volume Coastal Ocean Model,FVCOM）,构建了覆盖珠江河口及其上游网河区的高分辨率三维斜压数值模型,采用实测资料对其进行率定和验证,并开展了咸潮上溯的数值模拟计算。根据计算结果和实测资料,对磨刀门水道大、中、小潮期间的盐淡水分层与混合特征、盐分物质的分层输移机制进行分析,探讨其咸潮上溯强度时空分布差异的原因。结果表明:小潮期,底层累积盐通量明显大于表层,净输移方向为陆向;大潮期,表层累积盐通量明显大于底层,净输移方向为海向;而平衡点一般出现于中潮期,这就是磨刀门水道咸潮上溯最强和最弱时刻分别出现于小潮和大潮后的中潮期的原因所在。     

钱塘江河口水流-河床相互作用及对盐水入侵的影响

通过长系列实测水文、地形资料分析,钱塘江河口上段河床具有大冲大淤和洪冲潮淤的演变特性,影响河口上段的潮汐强弱,进而影响盐水入侵。若年内丰水期径流量大,则河床出现“大冲”,河床容积增大,潮汐增强,导致秋季强潮期盐水入侵加剧;反之,若年内丰水期径流量小,河床容积较小,导致秋季强潮期盐水入侵减弱。结果表明,钱塘江径流对盐水入侵存在直接和间接影响:直接影响是盐水入侵与径流量成反比;间接影响是通过径流冲刷河床,引起潮汐增大,间接导致盐水入侵加剧,这是钱塘江河口大冲大淤以及对潮汐巨大反作用的特性造成的。     

A numerical study of storm surge behavior in and around Lingdingyang Bay,Pearl River Estuary,China

Natural Hazards - A numerical study based on FVCOM model was carried out to investigate the storm surge behavior induced by Typhoon Mangkhut in and around Lingdingyang Bay, Pearl River Estuary....     

珠江口磨刀门枯季水文特征及河口动力过程

根据磨刀门2003年12月9~15日的大、中潮同步水文观测资料,分析了磨刀门枯季的潮汐、潮流、余流、悬移质含沙量、盐度等水文特征,并对枯季河口动力过程,如咸淡水混合、河口射流等进行了初步研究。在枯季由于径流较弱,潮流成为主要动力。表层由于受径流和风的影响余流基本上沿河道走向向下游,中层以下有稳定的向上的余流存在。枯季磨刀门含沙量较小(<1 kg/m3),盐度在平面上和垂向上均有一定变化。磨刀门枯季咸淡水混合类型为缓混合型,各站盐度分层参数均在0.01~1.0。从实测流速的分布情况来看,河口下层有反向的水流,存在明显的因密度差而形成的密度环流。根据枯季实测资料计算所得的密度弗劳德数,磨刀门枯季以浮力射流为主。     

珠江口伶仃洋ZK1钻孔的磁性地层学研究

伶仃洋地区年代格架的建立对区域古环境的重建及海陆交互作用的研究具有重要意义.利用磁性地层学和AMS 14C测年对珠江口伶仃洋ZK1钻孔(113°40′E、22°34′N,孔深100.3 m)0～32 m岩心进行了系统的年代学研究.5个样品的AMS 14C测试年龄为(486±120)～(2268±149)a BP.岩心的...     

Quantification and characterization of condensed organic matter in sediments from the Pearl River Delta and Estuary, South China

Nonhydrolyzable carbon （NHC） and black carbon （BC） were measured upon treatments with the HCl/HF/trifluoroacetic acid method, and with the combustion method at 375 ℃, respectively in three contaminated soils from the urban area of Guangzhou and twenty-two bulk and size-fractionated sediments from the Pearl River Delta and Estuary, China. The isolated NHC and BC fractions were also characterized using elementary analysis, radiocarbon accelerated mass spectroscopy （AMS）, solid state ^13C cross-polarization and magic angle spinning unclear magnetic resonance spectroscopy （^13C-CP/MAS NMR）, Fourier transformed infrared spectroscopy （FTIR）, and Raman microspectrometry. The results showed that the NHC and BC accounted for 25.6%-84.7 % and 4.14%-17.3%, respectively, of the total organic carbon （OC） with averages of 51.9% and 11.2% in the soils and sediments. For the less contaminated, low OC fiver and estuary sediments （WR and C08）, the OC and NHC concentrations increased with decreasing particle size.     

千岛湖配水工程对钱塘江河口盐水入侵影响

杭州市第二水源千岛湖配水工程（简称配水工程）的实施将引起富春江水库下泄流量及过程改变,从而对钱塘江河口盐水入侵产生影响。建立考虑涌潮作用的二维盐度数值模型,在验证钱塘江河口潮位和盐度的基础上,预测配水工程实施对河口盐水入侵距离和重要取水口含氯度超标时间的影响。研究表明:配水工程实施后,上游富春江水库若按现状调度方案,对枯水年影响大,咸水上溯距离增加3.7 km,沿岸取水口的可取水时间缩短0.2~3.6 d,丰、平水年盐水入侵和引水前相当;通过水库的优化调度,可基本消除枯水年引水造成的盐水入侵影响。为减少配水工程实施的盐水入侵影响,采用水库的优化调度模式是必要的。     

珠江口磨刀门水道盐度多步预测研究

为了减少咸潮灾害对人民生产生活的影响,进行盐度多步预测研究对建立有效的咸潮预警机制具有十分重要的意义.本文利用引入滞后因子的DE-RBF方法,以珠江口磨刀门水道为例,研究建立盐度多步预测模型的可行性.研究表明:滞后因子的引入使得预测模型的精度进一步提高,采用的DE搜索策略可以快速寻找到全局最优值.建立的5步盐度预测模型在100mg/L的允许误差范围内拟合度达到68.91%,而在200mg/L的情况下拟合度达到80.79%.而且这种方法具有普适性,在靠近外海的挂定角站可得到相似的结论.联石湾站和挂定角站的5步预测模型的预警准确度均超过90%,而预警错误率分别为9.47%和27.03%.     

Seasonal and spatial dynamics of trace elements in water and sediment from Pearl River Estuary, South China

In this study, spatial and seasonal dynamics of trace elements (Cu, Pb, Zn, Cd, As) in water and sediments were examined in the Pearl River Estuary (PRE), South China. The spatial variations of all the studied trace elements in sediments show the general decrease pattern from northwest to southeast side of the PRE, suggesting that the main sources of these trace elements may originate from terrestrial (rock and soil) weathering and human activities (e.g. agricultural, industrial and municipal wastewaters) via riverine inputs. The dissolved Cu, Pb, Cd, As, and Zn in PRE ranged from 0.34 to 3.26, 0.19 to 4.58, 0.0015 to 0.30, 0.16 to 8.18, 3.74 to 36.10 μg/L, respectively. There are obvious seasonal changes of dissolved trace elements in the PRE aquatic system. The maximum seasonal averages of all the dissolved trace elements excluding Zn were observed in summer, whereas dissolved Zn showed the minimum in this season. The overall spatial pattern of all the dissolved trace elements excluding Zn demonstrates decreasing trends from inshore to offshore, and the highest concentrations of dissolved Cu, Cd, As, and Zn appeared in the western part of PRE or the mouths of Pearl River, suggesting strong riverine and anthropogenic local inputs. PCA and correlation analysis show that the geochemical behavior of dissolved Cu and As are complicated and the dynamics of these two elements are controlled by various physicochemical parameters, whereas physicochemical parameters might play a relatively small role in the distributions of other studied trace elements.     

Organic matter distribution in the modern sediments of the Pearl River Estuary

We determined biomarker concentrations and distributions for surface sediments from 54 sites in the Pearl River Estuary, China. We focus on a suite of four biomarker-based indicators for relative terrestrial to marine organic matter (OM) source: the branched-isoprenoid tetraether (BIT) index, the ratio of high/low molecular weight n-alcohols [(ΣC_26–34/(ΣC₁₆₊₁₈ + ΣC_26–34)], an analogous ratio for n-fatty acids and the ΣC₂₉-steroids/(ΣC₂₉-steroids + brassicasterol) ratio. All four exhibit the same terrestrial to marine transition seen in previous bulk δ¹³C studies, but with an abrupt decrease in the relative terrestrial contribution across the delta front to pro-delta transition. Concentrations of terrestrially-derived biomarkers show no systematic decrease across the transition. Instead, the decrease in the proportion of terrestrial OM is due to a decrease in the sedimentation rate and associated terrestrial OM burial across the delta toe. This suggests that diagenetic controls on the fate of terrestrial OM, such as increased biodegradation where sedimentation rate is low, are subordinate to sedimentological processes. Biomarker-derived temperature values are cooler than expected for the lower Pearl River catchment, suggesting that the dominant component of the terrestrial OM is derived from the cooler upland regions of the catchment. The dominance of input from more distal terrain with greater topographic relief is evidence for the importance of geomorphological control on terrigenous OM transport. Collectively, the results demonstrate the importance of sedimentological processes in the supply, deposition and transport of terrestrial OM.     

山东省滨州市咸水入侵防治对策研究

滨州市深层地下水开采量主要由弹性储存量、越流补给量、径流量、压密释水量组成,地下水滞留时间长,更替时间缓慢.通过40年来深层地下水水动力场、水化学场和开发利用状况分析,认为过量开采是深层地下水位持续下降和降落漏斗形成的主因,地下水降落漏斗的快速扩展是咸水入侵的根本原因.采用解析法计算两个约束条件下深层地下水的允许开采量2001.9 m3/a.为合理开发利用地下水和防止成水入侵,提出了限量开采、回灌补源等措施.     

The extent of saltwater intrusion in southern Baldwin County,Alabama

Sea level rise (SLR) as a result of global warming has an impact on the increasing inundation on the coastal area. Nowadays, Semarang coastal area in Indonesia is already subject to coastal hazard due to tidal inundation and land subsidence. The impact of the inundation is predicted to be even more severe with the scenario of sea level rise. This paper concentrates on the risk assessment to the population, land use, and monetary losses as a result of coastal inundation under enhanced sea level rise. This paper uses the scenario of the depth of inundation to generate coastal inundation model using GIS-Technology. Anticipatory issues including methodology development for hazard assessment would be necessary for Semarang coastal area, and therefore, geo-information technology can be considered as a useful tool to rapidly assess the impact of the coastal hazard and evaluate the economic losses.     

珠江口盆地恩平凹陷油气充注期次及时间

应用储层流体包裹技术研究了恩平凹陷油气的成藏规律.结果表明,该区油气主要有两期充注,第一期充注时间较早(20 Ma),以油为主,原油主要来自深部文昌组中深湖相烃源岩,大量油气见于浅层储层;第二期充注时间较晚(5 Ma以后),以天然气为主,天然气主要源自文昌组烃源岩,油气主要分布在深层储集层中.研究认为第一期油气充注与盖层形成时间匹配不好,可能是浅层勘探失利的主要原因之一,因此勘探方向应以深层储层(文昌组)为主,寻找深层早期构造更为重要,是下一步勘探的重要领域.