On the use of apparent hydraulic diffusivity as an indicator of connectivity

Knudby, Christen; Carrera, Jesús

doi:10.1016/j.jhydrol.2006.02.026

Cited by 107 publications

(83 citation statements)

References 53 publications

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“…The direct high-k path between these locations helps explain the quick response to pumping that was recorded at W264. We note that this relationship between quick response behavior and a short path is consistent with results presented by Knudby and Carrera [2006] for two-dimensional synthetic transmissivity fields.…”

Section: Connectivity Properties and Shortest-path Resultssupporting

confidence: 90%

Identifying discrete geologic structures that produce anomalous hydraulic response: An inverse modeling approach

Ronayne

Gorelick

Caers

2008

Water Resources Research

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[1] Subsurface hydraulic response is controlled by discrete geologic structures in a variety of aquifer settings. In this work, we analyze data from the well-studied alluvial fan system that underlies the Lawrence Livermore National Laboratory. There, subsurface flow and transport behavior is strongly influenced by discrete channel deposits, which are embedded within less permeable floodplain deposits. We model the distribution of these deposits using a multiple-point geostatistical approach that enables simulation of geologically plausible connected permeable bodies consistent with a training image. By coupling the geostatistical model with a dynamic flow model in a simulation inversion framework, we identify specific channel structures that are consistent with transient aquifer test data at six observation wells. We perform shortest-path analysis to characterize the geometry of the simulated channels and to locate critical high-permeability conduits that control the system's response to pumping. In one area, all successful inverse solutions identify the same set of stacked channel deposits, a geologic feature that provides an explanation for anomalous response behavior observed during the aquifer test.

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Section: Connectivity Properties and Shortest-path Resultssupporting

confidence: 90%

Identifying discrete geologic structures that produce anomalous hydraulic response: An inverse modeling approach

Ronayne

Gorelick

Caers

2008

Water Resources Research

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“…However, there was a tendency for over-estimation of both saturated hydraulic conductivity and effective porosity (Table 1). Hydraulic conductivity and porosity are related through the hydraulic diffusivity term that controls the connectivity of a high-permeability flow path (Knudby and Carrera, 2006). Hydraulic diffusivity remains virtually the same with proportional change in both hydraulic conductivity and porosity.…”

Section: Conceptual and Numerical Models And Calibrationmentioning

confidence: 99%

Modelling hyporheic processes for regulated rivers under transient hydrological and hydrogeological conditions

Siergieiev

Ehlert

Reimann

et al. 2015

Hydrol. Earth Syst. Sci.

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Abstract. Understanding the effects of major hydrogeological controls on hyporheic exchange and bank storage is essential for river water management, groundwater abstraction, restoration and ecosystem sustainability. Analytical models cannot adequately represent complex settings with, for example, transient boundary conditions, varying geometry of surface water-groundwater interface, unsaturated and overland flow, etc. To understand the influence of parameters such as (1) sloping river banks, (2) varying hydraulic conductivity of the riverbed and (3) different river discharge wave scenarios on hyporheic exchange characteristics such as (a) bank storage, (b) return flows and (c) residence time, a 2-D hydrogeological conceptual model and, subsequently, an adequate numerical model were developed. The numerical model was calibrated against observations in the aquifer adjacent to the hydropower-regulated Lule River, northern Sweden, which has predominantly diurnal discharge fluctuations during summer and long-lasting discharge peaks during autumn and winter. Modelling results revealed that bank storage increased with river wave amplitude, wave duration and smaller slope of the river bank, while maximum exchange flux decreased with wave duration. When a homogeneous clogging layer covered the entire river-aquifer interface, hydraulic conductivity positively affected bank storage. The presence of a clogging layer with hydraulic conductivity < 0.001 m d −1 significantly reduced the exchange flows and virtually eliminated bank storage. The bank storage return/fill time ratio was positively related to wave amplitude and the hydraulic conductivity of the interface and negatively to wave duration and bank slope. Discharge oscillations with short duration and small amplitude decreased bank storage and, therefore, the hyporheic exchange, which has implications for solute fluxes, redox conditions and the potential of riverbeds as fish-spawning locations. Based on these results, river regulation strategies can be improved by considering the effect of certain wave event configurations on hyporheic exchange to ensure harmonious hydrogeochemical functioning of the river-aquifer interfaces and related ecosystems.

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“…It implies that the dynamic metrics can vary with time. Dynamic and static connectivity metrics are linked through complex relations [29,42,[56][57][58][59]. Dynamic metrics are easier to measure in the field.…”

Section: Introductionmentioning

confidence: 99%

Connectivity metrics for subsurface flow and transport

Renard

Allard

2013

Advances in Water Resources

337

258

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a b s t r a c tUnderstanding the role of connectivity for the characterization of heterogeneous porous aquifers or reservoirs is a very active and new field of research. In that framework, connectivity metrics are becoming important tools to describe a reservoir. In this paper, we provide a review of the various metrics that were proposed so far, and we classify them in four main groups. We define first the static connectivity metrics which depend only on the connectivity structure of the parameter fields (hydraulic conductivity or geological facies). By contrast, dynamic connectivity metrics are related to physical processes such as flow or transport. The dynamic metrics depend on the problem configuration and on the specific physics that is considered. Most dynamic connectivity metrics are directly expressed as a function of an upscaled physical parameter describing the overall behavior of the media. Another important distinction is that connectivity metrics can either be global or localized. The global metrics are not related to a specific location while the localized metrics relate to one or several specific points in the field. Using these metrics to characterize a given aquifer requires the possibility to measure dynamic connectivity metrics in the field, to relate them with static connectivity metrics, and to constrain models with those information. Some tools are already available for these different steps and reviewed here, but they are not yet routinely integrated in practical applications. This is why new steps should be added in hydrogeological studies to infer the connectivity structure and to better constrain the models. These steps must include specific field methodologies, interpretation techniques, and modeling tools to provide more realistic and more reliable forecasts in a broad range of applications.

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On the use of apparent hydraulic diffusivity as an indicator of connectivity

Cited by 107 publications

References 53 publications

Identifying discrete geologic structures that produce anomalous hydraulic response: An inverse modeling approach

Identifying discrete geologic structures that produce anomalous hydraulic response: An inverse modeling approach

Modelling hyporheic processes for regulated rivers under transient hydrological and hydrogeological conditions

Connectivity metrics for subsurface flow and transport

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