Sedimentary environment of the Faroe-Shetland and Faroe Bank Channels, north-east Atlantic, and the use of bedforms as indicators of bottom current velocity in the deep ocean

In the northeast Atlantic, much of the deep cold water flow between the Norwegian Sea and the main North Atlantic basin passes through the Faroe‐Shetland and Faroe Bank Channels, generating strong persistent bottom currents capable of eroding and transporting sediment up to and including gravel. A large variety of sedimentary bedforms, including scours, furrows, comet marks, barchan dunes, sand sheets and sediment drifts, is documented using sidescan sonar images, seismic profiles, seabed photographs and sediment cores from the floor of the channel. Published information on current velocities associated with the various bedforms has been used to reconstruct the pattern of bottom currents acting on the channel floor. The results broadly reflect the current pattern predicted on the basis of regional oceanographic observations, but add considerable detail. The internal consistency of the results suggests that the methods used are robust, giving confidence in the fine detail of the observed bottom current structure. Bottom current velocities in the range < 0·3 to > 1·0 m s^?1 are indicated by the range of observed bedforms, with the strongest currents associated with south‐west transport of Norwegian Sea Deep Water (NSDW) at water depths of 800–1200 m. The main NSDW flow forms a relatively narrow core that follows the base of the Faroes slope. This core follows the 90° change in trend of the Faroes slope at the junction between the Faroe‐Shetland and Faroe Bank Channels. The strongest currents within the NSDW core are found over the shallowest sill in the Faroe‐Shetland Channel and in the narrowest part of the channel immediately downstream of the sill, and are generated by topographic constriction of the flow. Eastward flow of deep water along the northern flank of the Wyville‐Thomson ridge suggests a complex current pattern with some recirculation of deep water within the deep Faroe Bank Channel basin. The observations suggest that Coriolis force is the main agent controlling the westward deflection of the NSDW into the Faroe Bank Channel, contradicting a previous suggestion that this was controlled by the topography of the Wyville Thomson Ridge.     

PLACE AS A SOURCE OF IDENTITY IN COLONIZING SOCIETIES: ISRAELI SETTLEMENTS IN GAZA

ABSTRACT. The tendency to reduce the role of places in the formation of sociospatial identities and to emphasize the impact of sociopolitical structures on place making is growing. We argue that, under certain conditions, places may become salient sources of identity formation. In addition, we suggest viewing different types of places on a continuum from mythical “big places,” to everyday‐life places, to parochial “little places.” We further suggest a distinction between mythical and everyday‐life senses of place. Following Zali Gurevitz, who describes the characteristics of West Bank Jewish settlers' mythical sense of place, we demonstrate how Gaza settlers only partially internalized their conception of place, adopting an everyday‐life conception of thereof. Yet place became a main source of identity for Gaza settlers, who viewed their experience in the settlements as an empowering process that helped them escape their marginality and join the national elite.     

高压喷射灌浆技术在强透水堤基处理中的应用

本文介绍了高压喷射灌浆技术在北江大堤强透水堤基处理中的应用．文中在分析堤基地层结构特征和物性指标的基础上，论述了高喷防渗墙的设计施工参数，根据已有围井检验结果，分析了各种地层高喷防渗墙的防渗效果，提出了用“单位渗水率”指标评价围封质量的新方法．文中根据大堤渗流观测资料和检验指标“单位渗水率”，建立了高喷防渗墙垂直截流堤基的渗流计算公式，并得出高喷防渗墙能有效地抑制住大堤堤基的渗流形变．     

Modeling streambank erosion and failure along protected and unprotected composite streambanks

Streambank retreat can be a significant contributor to total sediment and nutrient loading to streams. Process-based bank stability models, such as the Bank Stability and Toe Erosion Model (BSTEM), have been used to determine critical factors affecting streambank erosion and failure such as riparian vegetation and to estimate retreat rates over time. BSTEM has been successfully applied on a number of cohesive streambanks, but less so on composite banks consisting of both cohesive and noncohesive soils in highly sinuous streams. Composite streambanks can exhibit rapid and episodic bank retreat. The objectives of this research were twofold: (i) develop and apply simplified procedures for estimating root cohesion based on above- and below-ground biomass estimates and (ii) systematically apply BSTEM to a series of 10 composite streambanks distributed along the Barren Fork Creek in eastern Oklahoma to assess model sensitivity to root cohesion and model performance in predicting retreat. This research aimed to document the influence of riparian conservation practices on bank retreat rates and evaluated simplistic methods for incorporating such practices into such process-based models. Sites modeled included historically unprotected sites with no riparian vegetation and historically protected sites with riparian vegetation present during all or part of the 2003 to 2010 study period. The lateral retreat ranged from 4.1 to 74.8 m across the 10 sites and was largest at the historically unprotected sites in which retreat averaged 49.2 m. Protected sites had less bank retreat but with more variability in retreat rates per year. With calibration focused on the erodibility parameters, the model was able to match both the observed total amount of retreat as well as the timing of retreat at both the protected and unprotected sites as derived from aerial imagery. During calibration BSTEM was not sensitive to the specific value of the soil cohesion or the additional soil cohesion added due to roots for the cohesive topsoil layer, suggesting that the proposed simplified techniques could be used to estimate root cohesion values. The BSTEM modeling also provided an advantageous assessment tool for evaluating retreat rates compared to in situ bank retreat measurements due to the magnitude and episodic nature of streambank erosion and failures. Process-based models, such as BSTEM, may be necessary to incrementally model bank retreat in order to quantify actual streambank retreat rates and understand mechanisms of failure for the design of stabilization projects.     

Modelling of cantilever bank failure for peat-type meander bends in the source region of the Yellow River

Bank retreat involving a combination of fluvial erosion and bank collapse has been found to be a major contributor to sediment transport, lateral migration, and planform evolution of meandering rivers.Previous studies have largely examined the general mechanism of cantilever bank failure. However, the composite process of beam(toppling) failure caused by shear failure of the lower part composed of noncohesive soil remains poorly understood. The current paper investigates the diversity and coupli...     

Stream water infiltration, bank storage, and storage zone changes due to stream-stage fluctuations

During a flood period, stream-stage increases induce infiltration of stream water into an aquifer; subsequent declines in stream stage cause a reverse motion of the infiltrated water. This paper presents the results of the water exchange rate between a stream and aquifer, the storage volume of the infiltrated stream water in the surrounding aquifer (bank storage), and the storage zone. The storage zone is the part of aquifer where groundwater is replaced by stream water during the flood. MODFLOW was used to simulate stream–aquifer interactions and to quantify rates of stream infiltration and return flow. MODPATH was used to trace the pathlines of the infiltrated stream water and to determine the size of the storage zone. Simulations were focused on the analyses of the effects of the stream-stage fluctuation, aquifer properties, the hydraulic conductivity of streambed sediments, regional hydraulic gradients, and recharge and evapotranspiration (ET) rates on stream–aquifer interactions. Generally, for a given stream–aquifer system, larger flow rates result from larger stream-stage fluctuations; larger storage volumes and storage zones are produced by larger and longer-lasting fluctuations. For a given stream-stage hydrograph, a lower-permeable streambed, an aquitard, or an anisotropic aquifer of low vertical hydraulic conductivity can significantly reduce the rate of infiltration and limit the size of the storage zone. The bank storage solely caused by the stage fluctuation differs slightly between gaining and losing streams. Short-term rainfall recharge and ET loss in the shallow groundwater slightly influence on the flow rate, but their effects on bank storage in a larger area for a longer period can be considerable.     

Asian Development Bank's support for clean energy

The Asian Development Bank's (ADB) support for the development of the clean energy sector in Asia and the Pacific is examined, together with its implications for mitigating climate change. A key question is whether financing has shifted from fossil fuel projects to renewable energy and energy efficiency in the past decade (2000–2009). Financial data from the ADB – a multilateral source of significant financing in the region – are assessed, and 127 technology-deploying projects and 199 technical assistance projects are evaluated. The assessment suggests that clean energy assistance has gained momentum during the last few years, peaking in 2008, implying a considerable shift in energy investments from conventional fossil-fuel projects to clean energy. Although private sector involvement has been central to the ADB's investment policy, only 30% of funding has been channelled into this sector over the past decade. The reporting of clean energy investments has also progressed within the ADB by including renewable and energy efficiency components in conventional energy projects and other investments, which was not previously accounted for. Nevertheless, the ADB needs to address several challenges in the future, including sustaining funding for clean energy, strengthening private sector investments and improving financial reporting.     

峡谷高坝蓄水诱发近坝库盆及岸坡微变形机理研究现状

峡谷高坝蓄水诱发的库盆及岸坡微变形,多指由于高坝蓄水导致两岸山体应力状态调整而产生的非失稳变形,一般数厘米到数十厘米,有的研究亦称谷幅变形（水平向）、库盆变形（竖向）、河谷变形（库区内）等。目前仅在我国少数特高坝工程中开展过监测分析,如锦屏一级、小湾、溪洛渡等,其中谷幅变形是研究的重点。然而,目前关于这一变形的系统研究和定量分析较少,基于不同工程监测数据得到的变形规律有所差异,很难用单一的理论进行解释,所提出的机理尚不完备。特别地,由于可借鉴的工程经验不足,在设计中缺乏相应技术标准,高坝蓄水导致的岸坡微变形对坝体长期影响不得而知。此外,正在建设的白鹤滩（289m）、双江口（314m）等水电站,都需要面临峡谷高坝谷幅变形的问题。因此,本文综述了这一问题的研究现状,探讨了库盆及岸坡微变形可能的机理并进行了展望。     

海底广角地震剖面反演方法对比——以南海礼乐滩OBS剖面为例

广角地震测线（OBS973-2）位于南海南部陆缘,其地壳深部构造是研究南海共轭扩张及形成演化的直接证据之一.本文采用2D射线追踪技术,结合与之重合的多道地震测线（NH973-2）时深转换结果,对OBS973-2测线重新进行了正、反演研究,得到了礼乐滩及邻近海区的精细地壳结构.与前人结果相比,本文基于正反演速度模型,把测线分为陆壳区（0~200 km）、洋陆过渡区（200~280 km）和洋盆区（280~370 km）.地壳结构在不同区域差异明显,陆壳区沉积层厚度横向差异大,且速度横向不均匀,地壳整体厚度大（约20 km）,有横向速度差;洋陆过渡区速度和厚度横向均匀,地壳减薄（约8 km）;洋壳区地壳厚度减薄至6 km.与以往研究相比,新的认识集中在两个方面,（1）在方法上,综合广角地震和多道地震数据,借助正演和反演方法,能够得到更多更可靠的地壳结构信息.（2）在地壳结构上,结合广角地震与多道地震,得到洋陆过渡区莫霍面向海减薄的形态及其埋深（约12~18 km,海平面为0 km）;进一步验证礼乐滩区域在洋陆过渡区没有明显的高速层,为非火山型陆缘,其共轭扩张点为中沙地块;陆壳区上地壳强烈的拉张作用在速度模型表现出横向速度异常和低速区,在多道地震剖面上表现为大量10~20 km的正断层.