一种污水排海的近远区计算与控制方法──以大亚湾水容量计算及污水排海为例     

韩保新  彭海君  曾小清  胡康萍  吕先林 《热带海洋学报》1996,(4)

针对点容量计算中混合区限制的要求，采用了动量积分法、经验公式法和有限差分法，分别对污水排放后可能引起的近区、过渡区和远区的污水浓度变化进行了模拟预测，并就一定的限制性条件对容量点近区、高浓度混合区及容量点远区影响范围进行了分析。在大亚湾水容量计算及污水排海规划中的应用表明，该法具有计算机时较省、精度相对较高等优点。  相似文献   

礁膜配子放散条件的研究   总被引：2，自引：0，他引：2  

陈昌生 《台湾海峡》1996,15(2):154-158

本文报道了礁膜配子的放散与温度、光照、比重的关系。结果表明，自然海区的礁膜在白天大量放散配子。配子放散的适宜温度为１９－２１℃；光照为２０００－５０００ｌｘ时能促进配子大量放散出来；配子放散的适宜比重为１．０５－１．０２５；这些研究结果将为礁膜人工育苗提供一些科学依据。  相似文献   

Hydrodynamic modeling of flushing time in a small estuary of North Bay, Florida, USA   总被引：1，自引：0，他引：1  

Wenrui Huang   《Estuarine, Coastal and Shelf Science》2007,74(4):722

Freshwater fraction method is popular for cost-effective estimations of estuarine flushing time in response to freshwater inputs. However, due to the spatial variations of salinity, it is usually expensive to directly estimate the long-term freshwater fraction in the estuary from field observations. This paper presents the application of the 3D hydrodynamic model to estimate the distributions of salinity and thus the freshwater fractions for flushing time estimation. For a case study in a small estuary of the North Bay in Florida, USA, the hydrodynamic model was calibrated and verified using available field observations. Freshwater fractions in the estuary were determined by integrating freshwater fractions in model grids for the calculation of flushing time. The flushing time in the North Bay is calculated by the volume of freshwater fraction divided by the freshwater inflow, which is about 2.2 days under averaged flow conditions. Based on model simulations for a time series of freshwater inputs over a 2-year period, a power regression equation has been derived from model simulations to correlate estuarine flushing time to freshwater inputs. For freshwater input varying from 12 m³/s to 50 m³/s, flushing time in this small estuary of North Bay changes from 3.7 days to 1.8 days. In supporting estuarine management, the model can be used to examine the effects of upstream freshwater withdraw on estuarine salinity and flushing time.  相似文献   

洋浦近岸海域污染控制规划方案优化——Ⅰ.排污口位置优选     

孙英兰  孙长青  赵可胜  王学昌  张阁卿 《中国海洋大学学报(自然科学版)》1994,(Z1)

在洋浦近岸海域计算潮流场基础上,计算预选排污口附近海水质点运动轨迹及预测污染物浓度分布,最后,从环保角度出发,推荐了洋浦地区各开发区的排污口位置,为洋浦近岸海域污染控制规划方案的制定及其优化提供了依据。  相似文献   

山东省淡水枝角类的初步调查   总被引：4，自引：0，他引：4  

毛乾盛 《海洋湖沼通报》1993,(2):78-83

山东省淡水水域广阔,不仅河流多,而且湖泊、水库、坑塘星罗棋市,资源丰富。其中的淡水枝角类是水体食物链之重要环节,对渔业主产和环境保护工作具有相当重要的现实的意义。因此,必须对其更好地调查研究如培育利用。笔者多年来,就山东省若干地区的淡水枝角类进行采集、分类等研究工作。本文报道其初步结果——隶属7科,24属,71种。  相似文献   

海底泉对在海底有限延伸的越流含水层系统中地下水潮汐效应的增强作用     

杨颖  李海龙  夏玉强  孙萍萍 《地下水》2008,30(2):9-14

海底泉在滨海地下水排泄过程中起着重要的作用。本文给出了含有一个海底泉的在海底延伸的越流承压含水层系统中地下水水头在海潮作用下波动的近似解析解。该含水层顶底板隔水且向海底延伸有限距离。假设含水层的海底露头被一层隔水层覆盖,海底泉由一个渗透性很好的完全穿透海底含水层硕板的圆柱体渗漏天窗（海底泉孔）来表示。近似解析解中包含了6个参数：承压含水层的海潮传播参数,海底泉孔中心到海岸线的距离,表示泉的圆柱体的等效半径,海底泉孔中心到含水层海底露头处的距离,承压含水层的海潮载荷效率和弱透水层的越流。分析表明,如果海底泉孔中心到海岸线的距离远大于泉孔的等效半径,且海底泉孔中心到含水层海底露头处的距离远大于泉孔的等效半径时,解析解的近似误差可以忽略。然后本文讨论了解析解的两个基本性质,分析了海底泉对海底地下水水头波动的影响。  相似文献   

四川省九龙县娃娃沟泥石流运动特征与堵河成灾机制分析     

施蕾蕾  陈宁生  杨成林 《中国地质灾害与防治学报》2008,19(2):16-22

2006年7月16日娃娃沟流域暴发的大规模泥石流,给下游3个电站造成巨大经济损失,是大渡河流域一次典型的灾害性泥石流。分析得出,娃娃沟泥石流重度高、搬运能力强,泥石流固体物质砂、石混杂,粗大砾石含量高;暴发频率低、规模大,流速及峰值流量分别高达10．78m／s及798．5m^3／s;在汇口处,泥石流堆积物堵塞河道是引起下游电站受灾的重要原因,高重度、粗颗粒、大流量的组合是此次泥石流堵江的重要原因。堵河判别计算结果显示在发生百年一遇泥石流时,该断面均有发生堵河的可能。娃娃沟泥石流表明：①在大渡河支流的泥石流沟周边的中小电站极有可能在泥石流暴发时受到破坏。因此,电站建设过程中应加强对周边泥石流沟的防灾减灾工作;②虽然娃娃沟流域植被良好,但仍然发生了大规模泥石流。表明植被不能完全避免泥石流的发生,对于此类泥石流沟不能疏忽大意。  相似文献   

河流活性物质入海通量:概念与方法   总被引：1，自引：0，他引：1  

周国华  孙彬彬  刘占元  魏华玲  曾道明 《地质通报》2008,27(2):182-187

河流水体中呈溶解态和悬浮物结合态的元素活动性强,具有生态环境意义,查明其入海通量是当前生态地球化学评价的重要任务。通过总结前人的相关研究成果,确定了影响河流水体悬浮物的浓度及其矿物、化学组成的主要因素。从沿海经济带区域生态地球化学评价的实际需要出发,拟定了开展中国主要入海河流水溶态和悬浮物结合态元素入海通量调查的基本框架。  相似文献   

The ＂CO2-rich gas vents＂ of Mt. Amiata volcano （Tuscany, Central Italy）： Geochemistry,genetic mechanism and hazard evaluation     

Franco Tassi Orlando Vaselli Elena Lognoli Fabrizio Cuccoli Barbara Nisi Elena Ramaldi Sandro Moretti Luca Lombardi Bruno Capaccioni 《中国地球化学学报》2006,25(B08):70-71

Mt. Amiata （Southern Tuscany, Central Italy） is an extinct Quaternary volcano located in an area still marked by high heat-flow that is caused by deep seated （6-10 km） hot masses related to Pliocene magmatic activity. The anomalous geothermal gradient gives rise, within the Mesozoic limestone formation （Tuscan series）, to geothermal systems that fed the Ca-SO4 thermal springs characterizing this area. Besides of thermal fluids, several cold, dry CO2-rich gas emissions seep out on the NE flank of the volcano. These gas vents mostly consist of large sub-circular craters at variable depth and diameter （5-15 m and 10-50 m, respectively）, and represent a serious hazard for the local population, as testified by the several asphyxia casualties that have been repeatedly occurred within these morphological depressions. In this work, the chemical and isotopic compositions of the Mt. Amiata ＂CO2-rich gas vents＂ and the estimation of both the CO2 flux from the soil and the CO2 distribution in air of their surroundings, has been carried out in order to： （1） assess the origin of gases, （2） recognize the mechanism of formation for these gas emissions and their relationship with local tectonics, and （3） to evaluate the CO2 hazard in the high flux emanations. The chemical composition of the gases is largely dominated by CO2 （up to 98 % by vol） and shows relatively high concentrations of N2, CH4 and H2S （up to 1.1%, 0.9% and 3.9 % by vol, respectively）. These features, coupled with the carbon and nitrogen isotopic signatures, suggest that the origin of the main gas compounds may be related to the contribution of deep （i.e., thermometamorphic processes on carbonate formations for CO2） and shallow （i.e. thermal decomposition of organic material for CH4, N2 and H2S） sources.  相似文献   

The acid neutralizing capacity （ANC） of South Africa＇s freshwater ecosystems     

Stephanie de Villiers 《中国地球化学学报》2006,25(B08):146-146

Acidification is considered the most important one of the primary chemical stress factors that impact on freshwater ecosystems. In unpolluted freshwater systems, the primary controls on the degree of acidification are factors such as the geological substrate of the catchment area, the presence of organic acids secreted by vegetation in the river system, and equilibrium exchange of carbon dioxide with the atmosphere. Anthropogenic factors that can impact on the degree of acidification of freshwater systems include agricultural, mining and industrial activities, either through direct runoff into river systems or through deposition of atmospheric pollutants from these sources. The capacity factors alkalinity and acidity, which represent the acid- and base-neutralizing capacity （ANC and BCN） of an aqueous system, have been used as more reliable measures of the acidic character of freshwater systems than pH. Unlike pH, ANC and BNC are not affected by parameters such as temperature and pressure. Therefore, ANC has been employed as a predictor of biological status in critical load assessments. Freshwater systems with ANC＇s eq/L isμeq/L are considered sensitive to acidification, ANC=0 μbelow 150 commonly used as the predictor for fish species such as trout in lakes, and an eq/L as more realistic for streams. Acid-neutralizing capacity μANC value of 40 （ANC） can be determined by titration with a strong acid to a preselected equivalence point. Alternatively, it can be calculated as the difference between base cations （[BC]） and strong acid anions （[SAA]）： ANC=[BC]- [SAA]=[Ca^2＋]＋[Mg^2＋]＋[Na^＋]＋[K^＋]-[SO4^2-]-[NO3^-]-[Cl^-] To date, there has been no attempt to establish the ANC of South Africa＇s freshwater ecosystems or variability therein, despite the fact that long-term water quality monitoring data exist for all the parameters needed to calculate it according to the above equations. As a result, the relationship between the acid neutralizing capacity of freshwater ecosystems in South Africa and biodiversity factors, such as fish status, is unknown. Results of the first comprehensive （country-wide scale） evaluation of the acid neutralizing capacity of river systems in South Africa will be presented. Long-term monitoring data obtained from the Department of Water Affairs and Forestry （DWAF） from most of South Africa＇s river systems were used to establish geographic and temporal variabilities in ANC. The results show that the Berg and Breede River systems are most susceptible to acidification, and that geological substrate appears to explain most of the geographic variabilities observed.  相似文献