Large-scale Intrusion of shallow water into a vertical fracture zone in crystalline bedrock: Initial hydrochemical perturbation during tunnel construction at the Äspö Hard Rock Laboratory, southeastern Sweden

SUMMARY Boat-towed radio-magnetotelluric (RMT) measurements using signals between 14 and 250 kHz have attracted increasing attention in the near-surface applications for shallow water and archipelago areas. A few large-scale underground infrastructure projects, such as the Stockholm bypass in Sweden, are planned to pass underneath such water zones. However, in cases with high water salinity, RMT signals have a penetration depth of a few metres and do not reach the geological structures of interest in the underlying sediments and bedrock. To overcome this problem, controlled source signals at lower frequencies of 1.25 to 12.5 kHz can be utilized to improve the penetration depth and to enhance the resolution for modelling deeper underwater structures. Joint utilization of boat-towed RMT and controlled source audio-magnetotellurics (CSAMT) was tested for the first time at the Äspö Hard Rock Laboratory (HRL) site in south-eastern Sweden to demonstrate acquisition efficiency and improved resolution to model fracture zones along a 600-m long profile. Pronounced galvanic distortion effects observed in 1-D inversion models of the CSAMT data as well as the predominantly 2-D geological structures at this site motivated usage of 2-D inversion. Two standard academic inversion codes, EMILIA and MARE2DEM, were used to invert the RMT and CSAMT data. EMILIA, an object-oriented Gauss–Newton inversion code with modules for 2-D finite difference and 1-D semi-analytical solutions, was used to invert the RMT and CSAMT data separately and jointly under the plane-wave approximation for 2-D models. MARE2DEM, a Gauss–Newton inversion code for controlled source electromagnetic 2.5-D finite element solution, was modified to allow for inversions of RMT and CSAMT data accounting for source effects. Results of EMILIA and MARE2DEM reveal the previously known fracture zones in the models. The 2-D joint inversions of RMT and CSAMT data carried out with EMILIA and MARE2DEM show clear improvement compared with 2-D single inversions, especially in imaging uncertain fracture zones analysed in a previous study. Our results show that boat-towed RMT and CSAMT data acquisition systems can be utilized for detailed 2-D or 3-D surveys to characterize near-surface structures underneath shallow water areas. Potential future applications may include geo-engineering, geohazard investigations and mineral exploration.

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Towards Control of an Estuary

Water Science & Technology ◽

10.2166/wst.1987.0077 ◽

1987 ◽

Vol 19 (9) ◽

pp. 155-174

Author(s):

Henk L. F. Saeijs

Keyword(s):

Shallow Water ◽

Storm Surge ◽

Salt Marshes ◽

Large Scale ◽

Western Europe ◽

Oxygen Depletion ◽

Negative Effects ◽

Intertidal Flats ◽

Environmental Consequences ◽

Short Time

The Delta Project is in its final stage. In 1974 it was subjected to political reconsideration, but it is scheduled now for completion in 1987. The final touches are being put to the storm-surge barrier and two compartment dams that divide the Oosterschelde into three areas: one tidal, one with reduced tide, and one a freshwater lake. Compartmentalization will result in 13% of channels, 45% of intertidal flats and 59% of salt marshes being lost. There is a net gain of 7% of shallow-water areas. Human interventions with large scale impacts are not new in the Oosterschelde but the large scale and short time in which these interventions are taking place are, as is the creation of a controlled tidal system. This article focusses on the area with reduced tide and compares resent day and expected characteristics. In this reduced tidal part salt marshes will extend by 30–70%; intertidal flats will erode to a lower level and at their edges, and the area of shallow water will increase by 47%. Biomass production on the intertidal flats will decrease, with consequences for crustaceans, fishes and birds. The maximum number of waders counted on one day and the number of ‘bird-days' will decrease drastically, with negative effects for the wader populations of western Europe. The net area with a hard substratum in the reduced tidal part has more than doubled. Channels will become shallower. Detritus import will not change significantly. Stratification and oxygen depletion will be rare and local. The operation of the storm-surge barrier and the closure strategy chosen are very important for the ecosystem. Two optional closure strategies can be followed without any additional environmental consequences. It was essential to determine a clearly defined plan of action for the whole area, and to make land-use choices from the outset. How this was done is briefly described.

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Potential Use of Organic- and Hard-Rock Mine Wastes on Aided Phytostabilization of Large-Scale Mine Tailings under Semiarid Mediterranean Climatic Conditions: Short-Term Field Study

Applied and Environmental Soil Science ◽

10.1155/2012/895817 ◽

2012 ◽

Vol 2012 ◽

pp. 1-15 ◽

Cited By ~ 25

Author(s):

Claudia Santibañez ◽

Luz María de la Fuente ◽

Elena Bustamante ◽

Sergio Silva ◽

Pedro León-Lobos ◽

...

Keyword(s):

Mine Tailings ◽

Large Scale ◽

Management Practices ◽

Hard Rock ◽

Mine Waste ◽

Organic Amendments ◽

Dry Weight ◽

Climatic Conditions ◽

Goat Manure ◽

Site Rehabilitation

The study evaluated the efficacy of organic- and hard-rock mine waste type materials on aided phytostabilization of Cu mine tailings under semiarid Mediterranean conditions in order to promote integrated waste management practices at local levels and to rehabilitate large-scale (from 300 to 3,000 ha) postoperative tailings storage facilities (TSFs). A field trial with 13 treatments was established on a TSF to test the efficacy of six waste-type locally available amendments (grape and olive residues, biosolids, goat manure, sediments from irrigation canals, and rubble from Cu-oxide lixiviation piles) during early phases of site rehabilitation. Results showed that, even though an interesting range of waste-type materials were tested, biosolids (100 t ha-1dry weight, d.w.) and grape residues (200 t ha-1d.w.), either alone or mixed, were the most suitable organic amendments when incorporated into tailings to a depth of 20 cm. Incorporation of both rubble from Cu-oxide lixiviation piles and goat manure into upper tailings also had effective results. All these treatments improved chemical and microbiological properties of tailings and lead to a significant increase in plant yield after three years from trial establishment. Longer-term evaluations are, however required to evaluate self sustainability of created systems without further incorporation of amendments.

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Assessing the Numerical Accuracy of Complex Spherical Shallow-Water Flows

Monthly Weather Review ◽

10.1175/2007mwr2036.1 ◽

2007 ◽

Vol 135 (11) ◽

pp. 3876-3894 ◽

Cited By ~ 14

Author(s):

Ali R. Mohebalhojeh ◽

David G. Dritschel

Keyword(s):

Shallow Water ◽

Fourth Order ◽

Large Scale ◽

Numerical Accuracy ◽

Conservation Of Energy ◽

Water Flows ◽

Shallow Water Flows ◽

Low Froude Number ◽

Contour Advection ◽

High Reynolds

Abstract The representation of nonlinear shallow-water flows poses severe challenges for numerical modeling. The use of contour advection with contour surgery for potential vorticity (PV) within the contour-advective semi-Lagrangian (CASL) algorithm makes it possible to handle near-discontinuous distributions of PV with an accuracy beyond what is accessible to conventional algorithms used in numerical weather and climate prediction. The emergence of complex distributions of the materially conserved quantity PV, in the absence of forcing and dissipation, results from large-scale shearing and deformation and is a common feature of high Reynolds number flows in the atmosphere and oceans away from boundary layers. The near-discontinuous PV in CASL sets a limit on the actual numerical accuracy of the Eulerian, grid-based part of CASL. For the spherical shallow-water equations, the limit is studied by comparing the accuracy of CASL algorithms with second-order-centered, fourth-order-compact, and sixth-order-supercompact finite differencing in latitude in conjunction with a spectral treatment in longitude. The comparison is carried out on an unstable midlatitude jet at order one Rossby number and low Froude number that evolves into complex vortical structures with sharp gradients of PV. Quantitative measures of global conservation of energy and angular momentum, and of imbalance as diagnosed using PV inversion by means of Bolin–Charney balance, indicate that fourth-order differencing attains the highest numerical accuracy achievable for such nonlinear, advectively dominated flows.

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Viruses in granitic groundwater from 69 to 450 m depth of the Äspö hard rock laboratory, Sweden

The ISME Journal ◽

10.1038/ismej.2008.18 ◽

2008 ◽

Vol 2 (5) ◽

pp. 571-574 ◽

Cited By ~ 51

Author(s):

Jennifer E Kyle ◽

Hallgerd S C Eydal ◽

F Grant Ferris ◽

Karsten Pedersen

Keyword(s):

Hard Rock ◽

Rock Laboratory ◽

Granitic Groundwater

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A large-scale physical model test on frozen status in freeze-sealing pipe roof method for tunnel construction

Tunnelling and Underground Space Technology ◽

10.1016/j.tust.2017.10.004 ◽

2018 ◽

Vol 72 ◽

pp. 55-63 ◽

Cited By ~ 19

Author(s):

Xiangdong Hu ◽

Tao Fang ◽

Jin Chen ◽

Hui Ren ◽

Wang Guo

Keyword(s):

Physical Model ◽

Model Test ◽

Large Scale ◽

Physical Model Test ◽

Tunnel Construction

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Turbulence of Capillary Waves on Shallow Water

Fluids ◽

10.3390/fluids6050185 ◽

2021 ◽

Vol 6 (5) ◽

pp. 185

Author(s):

Natalia Vladimirova ◽

Ivan Vointsev ◽

Alena Skoba ◽

Gregory Falkovich

Keyword(s):

Shallow Water ◽

Large Scale ◽

Capillary Waves ◽

Total Momentum ◽

Reflection Symmetry ◽

Spontaneous Breakdown ◽

Developed Turbulence ◽

Degree Of Anisotropy ◽

Zero Momentum ◽

Square Box

We consider the developed turbulence of capillary waves on shallow water. Analytic theory shows that an isotropic cascade spectrum is unstable with respect to small angular perturbations, in particular, to spontaneous breakdown of the reflection symmetry and generation of nonzero momentum. By computer modeling we show that indeed a random pumping, generating on average zero momentum, produces turbulence with a nonzero total momentum. A strongly anisotropic large-scale pumping produces turbulence whose degree of anisotropy decreases along a cascade. It tends to saturation in the inertial interval and then further decreases in the dissipation interval. Surprisingly, neither the direction of the total momentum nor the direction of the compensated spectrum anisotropy is locked by our square box preferred directions (side or diagonal) but fluctuate.

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