Fault zone hydrogeology: introduction to the special issue

Bense, Victor; Shipton, Zoe K.; Kremer, Yannick; Kampman, Niko

doi:10.1111/gfl.12205

Cited by 12 publications

(7 citation statements)

References 9 publications

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“…Hydrogeological characterisation can provide information on the hydraulic behaviour of geological structures such as faults in fluvial and aeolian siliciclastic aquifers at such depths (Ford and Tellam 1994;Tesmer et al 2007). Indeed, faults in sandstone influence the potential for upwards transport of contaminants from both nuclear waste repositories and hydraulically fractured reservoirs of shale gas (Bense et al 2013(Bense et al , 2016Cai and Ofterdinger 2014;Flewelling and Sharma 2014). Geothermal production wells are planned in correspondence of extensional faults with large damage zones to exploit the property of maximum permeability parallel to the fracture planes (Loveless et al 2014;Moreno et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Permeability of rock discontinuities and faults in the Triassic Sherwood Sandstone Group (UK): insights for management of fluvio-aeolian aquifers worldwide

et al. 2019

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Fluvio-aeolian sedimentary successions host groundwater aquifers at shallow depths (<~0.15 km), which overlie geothermal and shale-gas reservoirs, and nuclear waste repositories at intermediate depths (~0.15-2.0 km). Additionally, such deposits represent petroleum reservoirs at greater depths (~2.0-4.0 km). The need to improve conceptual understanding of the hydraulic behaviour of fluvial-aeolian sandstone successions over a large depth interval (~0-4 km) is important for socioeconomic reasons. Thus, the hydraulic properties of the Triassic Sherwood Sandstone aquifer in the UK have been reviewed and compared to similar fluvioaeolian successions. The ratio between well-scale and core-plug-scale permeability (K well-test /K core-plug) acts as a proxy for the relative importance of fracture versus intergranular flow. This ratio (which typically varies from~2 to 100) indicates significant contribution of fractures to flow at relatively shallow depths (<~0.15 km). Here, permeability development is controlled by dissolution of calcite-dolomite in correspondence of fractures. The observed ratio (K well-test /K core-plug) decreases with depth, approaching unity, indicating that intergranular flow dominates at~1 km depth. At depths ≥~1 km, dissolution of carbonate cement by rock alteration due to groundwater flow is absent and fractures are closed. Aeolian and fluvial deposits behave differently in proximity to normal faults in the Sherwood Sandstone aquifer. Deformation bands in aeolian dune deposits strongly compartmentalize this aquifer. The hydro-structural properties of fluvio-aeolian deposits are also controlled by mineralogy in fault zones. A relative abundance of quartz vs. feldspar and clays in aeolian sandstones favours development of low-permeability deformation bands.

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Section: Introductionmentioning

confidence: 99%

Permeability of rock discontinuities and faults in the Triassic Sherwood Sandstone Group (UK): insights for management of fluvio-aeolian aquifers worldwide

et al. 2019

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“…In particular, the main faults around the resurgent block and the caldera boundaries were related to barriers to horizontal groundwater flow, which cause groundwater level steps, even if they act as vertical conduits for deep fluid transport (Bense et al, 2016). In addition, the juxtaposition of lithostratigraphic units with contrasting permeabilities, often due to vertical displacement, was carefully considered.…”

Section: Resultsmentioning

confidence: 99%

A GIS-Based Hydrogeological Approach to the Assessment of the Groundwater Circulation in the Ischia Volcanic Island (Italy)

et al. 2022

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Assessing the variations in space and time of groundwater circulation in volcanic islands is of paramount importance to the description of the hydro-geo-thermal system and implementation of hydrogeological, geochemical, and volcanic monitoring systems. In fact, the reliable reconstruction of the groundwater potentiometric surface in such composite volcanic aquifer systems can enable the identification of the most advantageous strategies for both the sustainable use of groundwater resources and the management of volcanic risk. Geographical Information System (GIS) platforms can support the integration and analysis of many spatial and temporal variables derived from monitoring of active volcanoes and the elaboration of spatially continuous data. However, open issues still affect the reliability and general applicability of common spatial interpolation methods in the case of groundwater potentiometric surfaces. This is related to the assessment of the main stratigraphic and volcano-tectonic features affecting the hydraulic head changes. With regard to the dynamically very active Ischia Island (Italy), this study illustrates a GIS-based hydrogeological approach to identify the most accurate interpolation method for mapping the potentiometric surface in complex hydrogeological terrains. The proposed approach has been applied to the existing dataset (1977–2003) stored by Istituto Nazionale di Geofisica e Vulcanologia. Based on a careful geological and hydrogeological survey, a total of 267 wells, from 5 to 250 m in depth, were processed. The data pre-processing involved four meteorological time-series data (1922–1997) and six long records of piezometric water levels (1930–1994). As a result, knowledge of the delineation of rather homogeneous stratigraphic and volcano-tectonic structures at the basin-scale has improved. Thus, new, more reliable potentiometric surfaces of the four main geothermal areas closest to the coast were produced during both dry and wet seasons. The reliability of the processed potentiometric surface was then validated by comparing the spatially continuous data with complementary field data. These findings point toward an optimal interpolation approach for representing the seasonal and areal distribution of main hydrogeological parameters in complex aquifer systems. Finally, insights into variations of hydrological behavior at an active volcanic area will foster an understanding of possible involvement of fresh and thermal waters in triggering phreatic explosions.

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“…As a result, these models are not yet optimally equipped for simulating three-dimensional groundwater flow in unconsolidated sediments near fault zones in the RVRS. However, this differentiation is important because several studies on groundwater flow near fault zones indicate a reduced groundwater flow in horizontal, cross-fault direction and an expected preferential flow in vertical direction (Bense, 2002;Lewis et al 2002;Bense & Person, 2006;Anderson & Bakker, 2008;Bense et al, 2008Bense et al, , 2016Howald et al, 2015;Gumm et al, 2016;Stober et al, 2016). In addition, heterogeneity should be considered.…”

Section: Fault Zone Permeability and Heterogeneitymentioning

confidence: 99%

An overview of fault zone permeabilities and groundwater level steps in the Roer Valley Rift System

Lapperre

Kasse

Bense

et al. 2019

Netherlands Journal of Geosciences

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Faults in the Roer Valley Rift System (RVRS) act as barriers to horizontal groundwater flow. This causes steep cross-fault groundwater level steps (hydraulic head differences). An overview of the size and distribution of fault-related groundwater level steps and associated fault zone permeabilities is thus far lacking. Such an overview would provide useful insights for nature restoration projects in areas with shallow groundwater levels (wijstgronden) on the foot wall of fault zones. In this review study, data on fault zone permeabilities and cross-fault hydraulic head differences were compiled from 39 sources of information, consisting of literature (starting from 1948), internal reports (e.g. from research institutes and drinking water companies), groundwater models, a geological database and new fieldwork. The data are unevenly distributed across the RVRS. Three-quarters of the data sources are related to the Peel Boundary Fault zone (PBFZ). This bias is probably caused by the visibility of fault scarps and fault-adjacent wet areas for the PBFZ, with the characteristic iron-rich groundwater seepage. Most data demonstrate a cross-fault phreatic groundwater level step of 1.0 to 2.5 m. Data for the Feldbiss Fault zone (FFZ) show phreatic cross-fault hydraulic head differences of 1.0 to 2.0 m. In situ measured hydraulic conductivity data (K) are scarce. Values vary over three orders of magnitude, from 0.013 to 22.1 m d−1, are non-directional and do not take into account heterogeneity caused by fault zones. The hydraulic conductivity (and hydraulic resistance) values used in three different groundwater models are obtained by calibration using field measurements. They also cover a large range, from 0.001 to 32 m d−1 and from 5 to 100,000 days. Heterogeneity is also not taken into account in these models. The overview only revealed locations with a clear cross-fault groundwater level step, and at many locations the faults are visible on aerial photographs as cropmarks or as soil moisture contrasts at the surface. Therefore, it seems likely that all faults have a reduced permeability, which determines the size of the groundwater level steps. In addition, our results show that cross-fault hydraulic head gradients also correlate with topographic, fault-induced offsets, for both the Peel Boundary and the Feldbiss fault zone.

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Fault zone hydrogeology: introduction to the special issue

Cited by 12 publications

References 9 publications

Permeability of rock discontinuities and faults in the Triassic Sherwood Sandstone Group (UK): insights for management of fluvio-aeolian aquifers worldwide

Permeability of rock discontinuities and faults in the Triassic Sherwood Sandstone Group (UK): insights for management of fluvio-aeolian aquifers worldwide

A GIS-Based Hydrogeological Approach to the Assessment of the Groundwater Circulation in the Ischia Volcanic Island (Italy)

An overview of fault zone permeabilities and groundwater level steps in the Roer Valley Rift System

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