The first deep Quaternary groundwater capture in Switzerland: combined use and environmental benefits     

J. F. Schneider  L. Rybach 《Environmental Geology》1999,39(2):144-148

 Foresighted and determined local authorities, purposeful exploration (i.e. by seismic reflection) and extensive testing led to the discovery of a substantial groundwater resource near the community of Seon (Switzerland) at a depth of 268–305 m. Production tests revealed a hydraulic conductivity of ∼5.10–5 m/s, transmissivity of ∼5.10–4 m²/s and a storage coefficient of ∼2% in the aquifer. Pumping up to 1500 l/min is sustainable; the water quality complies chemically and bacteriologically with drinking-water requirements. The residence time of several 10³ years, determined by isotope techniques, guarantees protection from surface contamination. The elevated temperature of 19.5  °C of the produced water enables combined use for drinking water and space heating. The environmental benefits are substantial: the emission reduction amounts up to 780 tons/year CO₂ and 1 ton/year SO₂. Received: 21 September 1998 · Accepted: 10 February 1999  相似文献   

Dead Sea sinkholes – an ever-developing hazard     

Y. Arkin  A. Gilat 《Environmental Geology》2000,39(7):711-722

 Sinkhole development along the western shore of the Dead Sea became a major concern in 1990 with the appearance of a series of holes 2–15 m diameter and up to 7 m deep in the Newe Zohar area. One of these sinkholes, below the asphalt surface of the main road along the western shore of the Dead Sea, was opened by a passing bus. Repeated infilling and collapse of these holes indicated the extent of this ongoing process and the significance of this developing hazard. Since then sinkholes have developed in other areas including Qalia, Ein Samar, Ein Gedi and Mineral Beach. Three main types of sinkholes have been recognized. Gravel holes occurring in alluvial fans, mud holes occurring in the intervening bays of clay deposits between fans and a combination of both types at the front of young alluvial fans where they overlap mud flats. Fossil, relict sinkholes have been observed in the channels of some old alluvial fans. Sinkhole development is directly related to the regression of the Dead Sea and the corresponding lowering of the regional water table. Continuation of this process widens the neritic zone enveloping the sea and increases the sinkhole hazard of the region. Received: 4 February 1999 · Accepted: 8 April 1999  相似文献   

On the way to airborne gravelometry based on 3D spatial data derived from images   总被引：1，自引：1，他引：0  

M. Detert  L. Kadinski  V. Weitbrecht 《国际泥沙研究》2018,33(1):84-92

This paper presents basic tests to develop an airborne photogrammetric methodology that derives grain size characteristics of gravel bed rivers. The data acquisition was done using a lightweight action cam and a hand-held digital single lens reflex camera. Image processing comprised the structure from motion technique and multiview-stereo algorithms to obtain digital elevation models of non-cohesive gravel beds. Laboratory results indicate that the method accuracy is about four to six times lower than laser-scan data when based on action cam data. The accuracy of digital elevation models computed via photos taken by the reflex camera is almost of the same range as the laser data. Field experiments were done to test the performance of image based gravelometry against manual surface sampling. For this application the action cam was mounted to a low-cost quadrocopter, while the reflex camera was operated by hand. Results indicate that this combination has a high potential to generate data from which characteristic grain size parameters can be estimated.  相似文献   

Depth of activation on a mixed sediment beach   总被引：1，自引：0，他引：1  

Sherestha Saini  Nancy L. Jackson  Karl F. Nordstrom 《Coastal Engineering》2009

The relationship between wave height and depth of sediment activation is evaluated on an estuarine beach to determine whether activation depth is less in pebbles than sand. Rods with washers were used to monitor three excavated beach plots filled with (1) pebbles with mean grain size of 11.5 mm; (2) sand and granules; and (3) sand, granules and pebbles. Plots were monitored for 26 events over 27 days. Significant wave heights ranged from 0.18 to 0.40 m and activation depths from 0.02 to 0.12 m. Activation depths in the pebble plot were less than the other two plots when waves reworked sediment not activated during previous tidal cycles. Proportionality coefficients for activation depth to wave height, when net change was < 0.02 m, were 0.24 in the pebble plot and 0.30–0.31 in the other plots when experimental fill sediments remained and 0.22 to 0.23 in all three plots over the entire monitoring period, which included activation of newly deposited native sediment. Results suggest that for similar wave heights, activation depths in pebbles is lower than in sand, granules and pebbles or sand and granules, but once waves have reworked the sediment there is little difference in activation depths.  相似文献   

Determination of wave–shoreline dynamics on a macrotidal gravel beach using Canonical Correlation Analysis     

Amaia Ruiz de Alegría-Arzaburu  Adrián Pedrozo-Acuña  José M. Horrillo-Caraballo  Gerhard Masselink  Dominic E. Reeve 《Coastal Engineering》2010

This paper describes the application of Canonical Correlation Analysis (CCA) to derive forcing–response relations between the wave climate and shoreline position on a macrotidal gravel barrier located in the southwest of the U.K., and to develop a tool to determine shoreline positions from wave records. The data sequences comprise wave climate recorded by a nearshore directional wave buoy and video-derived shorelines over a time span of one year and a half. The hydrodynamic conditions are used to determine the probability density function of wave heights and alongshore energy fluxes. These are then related to shoreline change through a CCA analysis. The CCA analysis identifies patterns of behaviour of the wave conditions and the shoreline position, and the relation between both patterns is found to provide useful information about the beach response to wave action. The analysis shows that the movement of sediment is greater at the southern end of the study area and that there is an immediate shoreline response to the wave action. In the case of coastal management it is more often the case that wave forecasts are available on a routine basis. The ability of the CCA to provide useful estimates of shorelines from wave conditions was tested by using measured waves to calculate the corresponding shoreline position from additional data at the end of the sequences. Shoreline positions determined with the CCA agreed well with the measured ones. Thus, the CCA is found to be a useful tool to determine unknown shoreline positions and support effective coastal management if good quality hydrodynamic and morphological data are available to input into the initial set-up of the technique.  相似文献   

Diagnostic investigation of impulsive pressures induced by plunging breakers impinging on gravel beaches     

Adrián Pedrozo-Acuña  Alec Torres-Freyermuth  Qingping Zou  Tian-Jian Hsu  Dominic E. Reeve 《Coastal Engineering》2010

This paper presents an integrated investigation of physical processes generating impulsive pressures under the action of plunging breakers impinging on gravel beaches. This work is an extension of a recent investigation which suggested that wave impacts from plunging breakers acting on gravel beaches may be a key mechanism to enhance sediment mobilisation. In particular, comparisons of full scale laboratory measurements against model results from a well-validated phase/depth-resolving numerical model based on the Reynolds–Averaged Navier–Stokes (RANS) equations are presented. This represents the first attempt at comparison with such a tool against observed hydrodynamics on steep (slope~1/8) gravel beaches at prototype scale. In order to understand how impulsive pressures are generated under plunging waves, the numerical model is used to carry out a detailed investigation to examine the role of each of the acceleration terms in the momentum balance. Consistent with prior studies, numerical results show that under plunging breakers the local acceleration (∂u/∂t) alone cannot be used as a proxy for pressure gradients. However, the contribution of the third term (w∂u/∂z) of total acceleration is recognized for the first time and indicates that this term has an important role in both the induced pressure gradient and sediment mobilisation as induced by this particular type of breaking. Furthermore, results suggest that a parameterisation of the pressure gradient in terms of ∂u/∂t+u∂u/∂x, may not suffice when dealing with plunging breakers and hence there is a lack of a suitable parameterisation of this process in the present literature. Thus, for different types of breaking it may be necessary to consider a different characterisation of the pressure gradient toward the parameterisation of sediment transport inside the surf zone.  相似文献   

Total load transport in gravel bed and sand bed rivers case study:Chelichay watershed     

Arman HADDADCHI  Mohammad H.OMID  Amir A.SDEHGHANI 《国际泥沙研究》2013,28(1):46-57

Field experiments were conducted on total load transport in the Chelichay River Basin,a mountainous catchment (1,400 km~2) located in north eastern of Iran,to evaluate total load formulas including four gravel bed rivers and a sand bed river(Qaresoo River).Gravel bed rivers in Chelichay River Basin can be grouped into two types;steep slope rivers with high shear values(Chehelchay River and Khormaloo River) and mild slope rivers with low shear values(Narmab River and Soosara River).Two depth integrating suspended load samplers(DH-48 and D-49),and two bed load samplers(Helley-Smith and BLSH) were used to measure total load.The performance is tested of 8 total load transport formulae including 4 macroscopic and 4 microscopic methods.A systematic and thorough analysis of 59 sets of data collected from sand bed river indicate that Yang and Engelund and Hansen reach to the better results, and from four gravel bed rivers confirmed that the methods of Karim and Kennedy and Engelund and Hansen yields the best results for steep slope rivers,and the methods of Einstein and Bijker are ranked highest in gradual slope rivers.  相似文献   

Vertical migration of Daphnia galeata – Evidence for the use of an alternative resource from a lethal environment     

《Limnologica》2017

Metazoans normally avoid anaerobic environments, at least when they are combined with toxic stress due to hydrogen sulfide. In Lake Speldrop, a small but deep gravel pit lake at the Lower Rhine, Daphnia galeata was found not only to dominate the zooplankton community, but was also regularly found in anoxic and even sulfidic layers during summer. We conducted field experiments with a newly developed “Zooplankton In-situ Incubator”, simulating vertical migrations of D. galeata. When daphnids were exposed to sulfidic conditions, mortality increased with exposure time, revealing LT₅₀-values between 129 and 42 min in relation to increasing concentrations of sulfide. Additionally, those experimental individuals originating from 12.5 m depth showed significantly higher mortality rates than those from 7.5 m depth. Further migration experiments showed that an interruption period of sulfidic exposition in less stressful environments reduced mortality rates significantly. Daphnids found in the hypolimnion belonged partly to moribund parts of the population; however, the majority of daphnids showed regular mowing activity and was able to withstand sulfidic conditions in the hypolimnion for a limited time. It is so far unclear what maybe the major ultimate factor for this type of short term migratory behavior, to seek for shelter or to use high amounts of sulfur bacteria as an alternative food resource.  相似文献   

南天山西部山前新生代晚期三期构造活动:来自乌鲁克恰提剖面砾石统计的证据   总被引：1，自引：0，他引：1  

刘聃  陈汉林  林秀斌  Karl-Heinz WYRWOLL  Geoffrey E BATT  程晓敢  李康  王芳 《岩石学报》2012,28(8):2414-2422

天山是印度与欧亚板块碰撞过程中,欧亚大陆内重新复活的一条重要的造山带,其拓展过程一直备受关注.南天山西部山前新生代晚期巨厚的砾岩层为构造变形和磁性地层研究带来了困难,限制了该地区新生代晚期造山带拓展过程的研究.本文选取南天山西部山前乌鲁克恰提剖面,对新生代晚期的阿图什组和西域组地层进行详细的描述、测量,并对砾石出露点进行砾石统计.结果显示南天山西部山前乌鲁克恰提地区新生代晚期阿图什组存在3期沉积旋回,第一旋回由冲积扇远端、河流相变为该旋回上部的冲积扇扇中沉积环境.砾石统计结果显示由该旋回中部至上部砾石磨圆度变差、大粒径砾石增多.第二旋回沉积环境以较为平静的湖相及少许河流相开始,变为该旋回上部的冲积扇环境.砾石统计结果也显示出与第一旋回相似的变化特征,即由该旋回中部至上部砾石磨圆度变差、大粒径砾石增多.第三旋回下部为冲积扇远端、冲积扇扇中环境,上部变为扇根环境.砾石统计显示该旋回下部至上部,火成岩和变质岩等不稳定成分增多,磨圆度则呈现棱角状砾石显著增多的趋势,砾石粒径也明显增大.西域组则延续第三旋回的趋势,表现为山前快速堆积砾石沉积,砾石磨圆、分选呈显著变差趋势,粒径持续变大.从阿图什组第一旋回至西域组,砾石的磨圆度呈现变差的趋势,而粒径则表现为明显的增大趋势,这表明晚新生代(5.6Ma以来),褶皱冲断带不断向盆地拓展,物源区距离沉积区越来越近.这些结果表明南天山西部山前新生代晚期(5.6Ma以来)存在3期构造活动,为南天山山前晚新生代的多期拓展提供了证据.  相似文献   

塔里木DB区块砾石层特征及对优快钻井影响   总被引：1，自引：0，他引：1  

王廷民  梁红军  李皋  秦丽平  贾红军  曾永清  张志 《新疆地质》2012,30(1):113-115

塔里木DB区块浅层砾石研磨性强,钻井过程中井壁稳定性差、机械钻速低等问题较突出,严重影响深层油气勘探进展.本研究结合工程地质资料及室内实验,重点对该区岩石矿物成分随井深变化规律、胶结特征及水化过程研究,得出该区第四系到库车组上部层段砾石胶结强度低,且含大量水敏性粘土矿物.库车组下部、康村组和吉迪克组砾石胶结致密,成岩性好,不含膨胀性粘土矿物.研究成果可为今后该区砾石层段气体钻井等安全优快钻井技术提供理论依据.  相似文献