Beaver dam analogues drive heterogeneous groundwater–surface water interactions     

Jeffrey Wade  Laura Lautz  Christa Kelleher  Philippe Vidon  Julianne Davis  Julio Beltran  Casey Pearce 《水文研究》2020,34(26):5340-5353

Beaver dam analogues (BDAs) are a cost-effective stream restoration approach that leverages the recognized environmental benefits of natural beaver dams on channel stability and local hydrology. Although natural beaver dams are known to exert considerable influence on the hydrologic conditions of a stream system by mediating geomorphic processes, nutrient cycling, and groundwater–surface water interactions, the impacts of beaver-derived restoration methods on groundwater–surface water exchange are poorly characterized. To address this deficit, we monitored hyporheic exchange fluxes and streambed porewater biogeochemistry across a sequence of BDAs installed along a central Wyoming stream during the summer of 2019. Streambed fluxes were quantified by heat tracing methods and vertical hydraulic gradients. Biogeochemical activity was evaluated using major ion porewater chemistry and principal component analysis. Vertical fluxes of approximately 1.0 m/day were observed around the BDAs, as was the development of spatially heterogeneous zones of nitrate production, groundwater upwelling, and anaerobic reduction. Strong contrasts in hyporheic zone processes were observed across BDAs of differing sizes. This suggests that structures may function with size-dependent behaviour, only altering groundwater–surface water interactions after a threshold hydraulic step height is exceeded. Patterns of hyporheic exchange and biogeochemical cycling around the studied BDAs resemble those around natural beaver dams, suggesting that BDAs may provide comparable benefits to channel complexity and near-stream function over a 1-year period.  相似文献   

Seal integrity and feasibility of CO<Subscript>2</Subscript> sequestration in the Teapot Dome EOR pilot: geomechanical site characterization     

Laura Chiaramonte  Mark D. Zoback  Julio Friedmann  Vicki Stamp 《Environmental Geology》2008,54(8):1667-1675

This paper reports a preliminary investigation of CO₂ sequestration and seal integrity at Teapot Dome oil field, Wyoming, USA, with the objective of predicting the potential risk of CO₂ leakage along reservoir-bounding faults. CO₂ injection into reservoirs creates anomalously high pore pressure at the top of the reservoir that could potentially hydraulically fracture the caprock or trigger slip on reservoir-bounding faults. The Tensleep Formation, a Pennsylvanian age eolian sandstone is evaluated as the target horizon for a pilot CO₂ EOR-carbon storage experiment, in a three-way closure trap against a bounding fault, termed the S1 fault. A preliminary geomechanical model of the Tensleep Formation has been developed to evaluate the potential for CO₂ injection inducing slip on the S1 fault and thus threatening seal integrity. Uncertainties in the stress tensor and fault geometry have been incorporated into the analysis using Monte Carlo simulation. The authors find that even the most pessimistic risk scenario would require ∼10 MPa of excess pressure to cause the S1 fault to reactivate and provide a potential leakage pathway. This would correspond to a CO₂ column height of ∼1,500 m, whereas the structural closure of the Tensleep Formation in the pilot injection area does not exceed 100 m. It is therefore apparent that CO₂ injection is not likely to compromise the S1 fault stability. Better constraint of the least principal stress is needed to establish a more reliable estimate of the maximum reservoir pressure required to hydrofracture the caprock.  相似文献   

深层裂缝性储层防漏堵漏实验评价研究          下载免费PDF全文

范钢  张宏刚 《探矿工程》2008,35(7):80-83

深层裂缝性气藏具有异常高压、高产等特点,钻井完井过程中易出现又喷又漏等复杂事故,因此需做好“防漏为主、堵漏为辅”的防漏堵漏措施。通过全尺寸堵漏装置进行了高压静态、动态模拟堵漏实验,优选配方组合,并系统评价了防漏、堵漏配方的封堵能力、承压能力以及酸溶性,评价研究出的防漏堵漏配方,具有酸溶率高、堵塞强度高、返排效果好等特点,为防漏、堵漏方案现场实施提供依据。  相似文献   

青岛液体化工码头苯罐泄漏对大气环境的影响     

尹相淳  战闰  宋树林  魏修华 《海岸工程》2003,22(3):52-58

预测和评价了青岛港液体化工码头苯贮罐苯泄漏对大气环境的影响．结果表明，苯罐一旦发生泄苯事故，会对大气环境造成不同程度的影响；在最不利天气条件下，泄漏挥发量为3375kg，会导致22人死亡；泄漏挥发量为1237kg，会导致4人死亡；如果同样的泄苯挥发量，发生在微风条件下，则分别有4人死亡和无人死亡；若发生33kg泄漏挥发量，无论在何种天气条件下，都不会导致人员伤亡。  相似文献   

Simulation of green water flow on deck using non-linear dam breaking theory     

O. Yilmaz  A. Incecik  J. C. Han 《Ocean Engineering》2003,30(5):601-610

Experiments carried out with models of floating production, storage and offloading platforms (FPSOs) showed that the flow of water over the deck edge, onto the deck resembled a suddenly released wall of water rather than a breaking wave. Therefore green water flow onto the deck was simulated using dam breaking theory, but the theory’s shallow-water assumptions may be limiting. In this paper a non-linear dam breaking problem is formulated. Equations of motion in the Lagrangian form are used and the solution is sought as an infinite series in time. Comparisons with the shallow water approximation are carried out.  相似文献   

新建水坝对下游已建水工建筑物的影响分析     

宋子东 《海岸工程》2005,24(1):59-62

分析了新建水坝及社会经济发展因素对坝下游水流及泥沙的影响，用一个简易河床模型来说明新建大坝后下游河床的演变规律，通过坝下游河床一般演变分析来阐述局部冲刷对已建水工建筑物基础的影响及对已建水工建筑基础的防护措施。  相似文献   

编织袋充填砂结构在围堰工程中的应用     

高存贵  孟琪 《海岸工程》2006,25(4):55-59

结合青岛市四方区围海造地工程的实例,分析了在厚度较大的软弱地基层上水下铺设大型编织布袋作为围堰的主体结构的优点和结构特点,重点介绍了施工工艺以及在施工过程中需注意的问题。  相似文献   

基于分布式检测与决策融合的海底油气管线检漏   总被引：3，自引：0，他引：3  

白莉  岳前进崔莉 《海洋工程》2006,24(1):55-59

利用多传感器的信息融合思想，提出分布式检测与决策融合方法进行长距离海底管线泄漏监测。试验水管和天然气／凝析油管线现场数据分析表明此算法不仅降低了误报警概率，且对流体在输送过程中动态变化具有稳健性。  相似文献   

Fully nonlinear numerical wave tank (NWT) simulations and wave run-up prediction around 3-D structures     

J. -C. Park  M. -H. Kim  H. Miyata  H. -H. Chun 《Ocean Engineering》2003,30(15):1969-1996

A finite-difference scheme and a modified marker-and-cell (MAC) algorithm have been developed to investigate the interactions of fully nonlinear waves with two- or three-dimensional structures of arbitrary shape. The Navier–Stokes (NS) and continuity equations are solved in the computational domain and the boundary values are updated at each time step by the finite-difference time-marching scheme in the framework of a rectangular coordinate system. The fully nonlinear kinematic free-surface condition is implemented by the marker-density function (MDF) technique developed for two fluid layers.To demonstrate the capability and accuracy of the present method, the numerical simulation of backstep flows with free-surface, and the numerical tests of the MDF technique with limit functions are conducted. The 3D program was then applied to nonlinear wave interactions with conical gravity platforms of circular and octagonal cross-sections. The numerical prediction of maximum wave run-up on arctic structures is compared with the prediction of the Shore Protection Manual (SPM) method and those of linear and second-order diffraction analyses based on potential theory and boundary element method (BEM). Through this comparison, the effects of non-linearity and viscosity on wave loading and run-up are discussed.  相似文献   

黄河三角洲沿岸海浪风暴潮耦合作用漫堤风险评估研究   总被引：5，自引：3，他引：5  

尹宝树  徐艳青  任鲁川  杨德周  程明华 《海洋与湖沼》2006,37(5):457-463

海浪、风暴潮是重要的海洋灾害因子,过去人们主要对这些灾害因子本身进行研究,而对它们作用的承灾体研究甚少。实际上,只有它们作用的承灾体遭到破坏,才产生海洋灾害。本研究的目的就是要针对海浪风暴潮漫堤灾害,提出漫堤灾害的风险评估标准及风险评估方法和程式,为沿海防灾减灾提供科学依据。针对黄河三角洲示范区,根据漫堤程度,提出了漫堤灾害风险等级标准,并基于建立的海浪和风暴潮潮汐数值模式及长期预测结果,提出了风险评估方法和程式步骤。对黄河三角洲近岸海域主要堤段进行了多年一遇和典型台风过程漫堤灾害的风险评估。得到的结果是:该区沿岸海堤在风暴潮水位下一般都不能发生水位漫堤现象,只有加上波浪作用时,才会出现海水漫堤;当发生五十年一遇的风暴潮、浪时,多数的海堤的风暴潮、浪漫堤灾害风险在3—4级,即有效波高的浪已爬上或接近爬到堤顶;9216和9711号台风所产生的风暴潮、浪灾害约为150—200年一遇的情况。从实际情况看,本研究中提出的漫堤风险评估标准、评估方法是可行的,评估结果为有效防减海浪风暴潮漫堤灾害造成的损失提供了参考。  相似文献