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381.
湖泊流体动力学模型及实验   总被引:1,自引:1,他引:0       下载免费PDF全文
从二维浅水非恒定流的控制方程出发,建立了一个二维湖泊流体动力学模型.并根据天津于桥水库的实际情况,对该水库引水期和非引水期的湖水流场的不同情况进行了模拟试验.结果表明,在引水期水库的流场达到稳定状态时,水库流场有一个自东向西的水流主要通道.还对水库出口处有初始水体流速的情况进行了模拟.模拟的结果与于桥水库的实际污染物浓度分布基本一致.   相似文献   
382.
New technologies are in urgent need of unconventional hydrocarbon exploration and development in China.This paper provides a brief introduction and analysis of a new three-dimensional(3D)geomechanical restoration method developed in recent years.After an in-depth discussion on the technical principle and specific characteristics of the fields,we designed a feasible workflow for two oil-gas fields with great unconventional oil-gas resource potentials in China(Weiyuan and Jiulongshan oil-gas fields of Sichuan).After discussing the major challenges and limitations of the new technology,we also suggest its research efforts and future application prospect It is shown that the new technology will be an effective method to facilitate the exploration and development of unconventional oil and gas resources in China.  相似文献   
383.
Abstract

Reservoir water environment is a grey system. The grey clustering method is applied to assessing the reservoir water environment to establish a relatively complete model suitable for the reservoir eutrophication evaluation and appropriately evaluate the quality of reservoir water, providing evidence for reservoir management. According to China’s lakes and reservoir eutrophication criteria and the characteristics of China’s eutrophication, as well as certain evaluation indices, the degree of eutrophication is classified into six categories with the utilization of grey classified whitening weight function to represent the boundaries of classification, to determine the clustering weight and clustering coefficient of each index in grey classifications, and the classification of each clustering object. The comprehensive evaluation of reservoir eutrophication is established on such a foundation, with Sichuan Shengzhong Reservoir as the survey object and the analysis of the data attained by several typical monitoring points there in 2006. It is found that eutrophication of Tiebian Power Generation Station, Guoyuanchang and Dashiqiao Bridge is the heaviest, Tielusi and Qinggangya the second, and Lijiaba the least. The eutrophication of this reservoir is closely relevant to the irrational exploitation in its surrounding areas, especially to the aggravation of the non-point source pollution and the increase of net-culture fishing. Therefore, it is feasible to use grey clustering in environment quality evaluation, and the point lies in the correct division of grey whitening function  相似文献   
384.
Lake Okeechobee is the major source of freshwater in Southern Florida. With the increasing possibility of water stress, determining how to manage water during drought periods is essential to the operation of the Lake. This study deals with operational problems related to the management of Lake Okeechobee and the challenges involved in the implementation of hedging policy. We examine the implications of applying a theoretical hedging rule approach, comprising inter‐ and intrayear models, for the management of Lake Okeechobee and explore several optional hedging policies. The results demonstrate that hedging rules could reduce profit loss particularly under serious water stress, and might be applied sooner to mitigate the risk of severe water shortages. We suggested that the management of Lake Okeechobee should consider both short‐ and long‐term hedging nested. It is also demonstrated that the practical applicability of rolling decision making with updated forecast. Based on the results of the model, the merits of explicit optional hedging rules are demonstrated.  相似文献   
385.
As demand for water in the southwestern United States increases and climate change potentially decreases the natural flows in the Colorado River system, there will be increased need to optimize the water supply. Lake Powell is a large reservoir with potentially high loss rates to bank storage and evaporation. Bank storage is estimated as a residual in the reservoir water balance. Estimates of local inflow contribute uncertainty to estimates of bank storage. Regression analyses of local inflow with gaged tributaries have improved the estimate of local inflow. Using a stochastic estimate of local inflow based on the standard error of the regression estimator and of gross evaporation based on observed variability at Lake Mead, a reservoir water balance was used to estimate that more than 14.8 billion cubic meters (Gm3) has been stored in the banks, with a 90% probability that the value is actually between 11.8 and 18.5 Gm3. Groundwater models developed by others, observed groundwater levels, and simple transmissivity calculations confirm these bank storage estimates. Assuming a constant bank storage fraction for simulations of the future may cause managers to underestimate the actual losses from the reservoir. Updated management regimes which account more accurately for bank storage and evaporation could save water that will otherwise be lost to the banks or evaporation.  相似文献   
386.
作为生态脆弱区和全国集中连片分布的贫困地区之一 ,库区可持续发展面临一系列障碍 ,主要表现为人口超载 ,素质低下 ;耕地稀缺 ,人地矛盾尖锐 ;生态恶化 ,环境破坏严重 ;经济发展迟缓 ,贫困问题突出。针对上述问题 ,以三峡库区为例 ,结合其实际情况 ,文章给出了相应的治理策略。  相似文献   
387.
大口子水库的生物学调查与评价   总被引:5,自引:0,他引:5       下载免费PDF全文
为了解大口子水库水质的污染状况及污染趋势,淮安市环境监测中心站于“九五”期间对大口子水库进行了生物分析指标的监测和生物学评价。结果表明,“九五”期间,大口子水库的水质呈典型富营养化状态,且营养化程度有加重趋势;底栖动物群落的调查结果显示,化学毒性污染稍有好转,有机物污染占主导地位。提出,该水域不宜继续作为养殖基地进行水产养殖,对其污染的治理已刻不容缓。  相似文献   
388.
ABSTRACT: In this paper, a system approach to water resources development in Tehran Metropolitan Area, with its complex system of water supply and demands, is discussed. Water resources in this region include water storage in the Lar, Latyan, and Karaj reservoirs, the Tehran aquifer, as well as water discharge in local rivers and in drainage channels (mainly supplied by urban runoff and wastewater). This study consists of three phases of long‐term water resources planning and management in the Tehran metropolitan area. In each phase, a different level of details among different components of the system is considered. In the first phase, optimal operating policies for Tehran reservoirs and a decision support system are developed. In the second phase, interactions between surface and ground water resources as well as surface runoffs and wastewater disposal in different subareas are investigated. The water table fluctuations as a result of implementing sewerage collection project was also simulated. In the last phase, long‐term scenarios for water resources and agricultural development in the Southern part of Tehran are defined, and the effects of each scenario on the quality and quantity of surface and ground water resources are studied.  相似文献   
389.
Reservoirs have been served as the major source of drinking water for dozens of years. The water quality safety of large and medium reservoirs increasingly becomes the focus of public concern. Field test has proved that water-lifting and aeration system (WLAS) is a piece of effective equipment for in situ control and improvement of water quality. However, its intrinsic bioremediation mechanism, especially for nitrogen removal, still lacks in-depth investigation. Hence, the dynamic changes in water quality parameters, carbon source metabolism, species compositions and co-occurrence patterns of microbial communities were systematically studied in Jinpen Reservoir within a whole WLAS running cycle. The WLAS operation could efficiently reduce organic carbon (19.77%), nitrogen (21.55%) and phosphorus (65.60%), respectively. Biolog analysis revealed that the microbial metabolic capacities were enhanced via WLAS operation, especially in bottom water. High-throughput sequencing demonstrated that WLAS operation altered the diversity and distributions of microbial communities in the source water. The most dominant genus accountable for aerobic denitrification was identified as Dechloromonas. Furthermore, network analysis revealed that microorganisms interacted more closely through WLAS operation. Oxidation-reduction potential (ORP) and total nitrogen (TN) were regarded as the two main physicochemical parameters influencing microbial community structures, as confirmed by redundancy analysis (RDA) and Mantel test. Overall, the results will provide a scientific basis and an effective way for strengthening the in-situ bioremediation of micro-polluted source water.  相似文献   
390.
姜平 《地球与环境》2001,29(2):52-57
千米桥潜山构造位于黄骅坳陷北大港构造带。位于该构造的板深 7井在奥陶系地层试油 ,获日产凝析油 143 .36吨 ,日产气 2 75 30 9m3。这一重大发现标志着大港油田古潜山的勘探获得重大突破。千米桥潜山凝析油气主要来自板桥凹陷Es33 段偏腐殖型烃源岩 ,油气在沙一段沉积时期进入潜山 ,明化镇组沉积时期是油气大量运聚、成藏时期。千米桥潜山属于气侵型凝析气藏 ,并具多期成藏的特点。板深 4井油气藏受到扩散作用的影响。气侵是造成凝析油高含蜡的主要原因。  相似文献   
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