Flow channelling and variability in transit times and tortuosity in a fractured rock model with small scale heterogeneity

<p>Transit times and tortuosity for advective particles following water flow in a three-dimensional discrete fracture network with high-resolution representation of internal fracture heterogeneity in aperture is investigated using a numerical model with a stochastic Lagrangian transport framew...

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Main Author: A. Frampton
Format: Article
Language:English
Published: Copernicus Publications 2025-01-01
Series:Advances in Geosciences
Online Access:https://adgeo.copernicus.org/articles/65/149/2025/adgeo-65-149-2025.pdf
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author A. Frampton
A. Frampton
author_facet A. Frampton
A. Frampton
author_sort A. Frampton
collection DOAJ
description <p>Transit times and tortuosity for advective particles following water flow in a three-dimensional discrete fracture network with high-resolution representation of internal fracture heterogeneity in aperture is investigated using a numerical model with a stochastic Lagrangian transport framework. The fracture network properties are obtained from field measurements and data of a deep fractured rock formation in the Forsmark site in Sweden. Different assumptions for describing the variance and correlation length used for internal heterogeneity of fracture aperture fields are considered. It is shown that cases with strong variance and correlation length cause earlier first arrivals and delayed late arrivals, thereby extending the range of the transit time breakthrough distribution, compared to the assumption of constant fracture aperture. Also, the timing of peak mass arrival is delayed and its density is reduced. Furthermore, a strong correlation between transit time and tortuosity which occurs for early and bulk mass arrival is revealed, which breaks down for late mass arrival. Thereby two transport regimes are identified, where a first regime is mainly controlled by the network structure and exhibits strong correlation with tortuosity, and a second regime is mainly controlled by the fracture aperture heterogeneity and exhibits weak correlation with tortuosity.</p>
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spelling doaj-art-19440dd0701741c78180664551f52b932025-01-08T10:55:13ZengCopernicus PublicationsAdvances in Geosciences1680-73401680-73592025-01-016514915810.5194/adgeo-65-149-2025Flow channelling and variability in transit times and tortuosity in a fractured rock model with small scale heterogeneityA. Frampton0A. Frampton1Department of Physical Geography, Stockholm University, Stockholm, SwedenBolin Centre for Climate Research, Stockholm University, Stockholm, Sweden<p>Transit times and tortuosity for advective particles following water flow in a three-dimensional discrete fracture network with high-resolution representation of internal fracture heterogeneity in aperture is investigated using a numerical model with a stochastic Lagrangian transport framework. The fracture network properties are obtained from field measurements and data of a deep fractured rock formation in the Forsmark site in Sweden. Different assumptions for describing the variance and correlation length used for internal heterogeneity of fracture aperture fields are considered. It is shown that cases with strong variance and correlation length cause earlier first arrivals and delayed late arrivals, thereby extending the range of the transit time breakthrough distribution, compared to the assumption of constant fracture aperture. Also, the timing of peak mass arrival is delayed and its density is reduced. Furthermore, a strong correlation between transit time and tortuosity which occurs for early and bulk mass arrival is revealed, which breaks down for late mass arrival. Thereby two transport regimes are identified, where a first regime is mainly controlled by the network structure and exhibits strong correlation with tortuosity, and a second regime is mainly controlled by the fracture aperture heterogeneity and exhibits weak correlation with tortuosity.</p>https://adgeo.copernicus.org/articles/65/149/2025/adgeo-65-149-2025.pdf
spellingShingle A. Frampton
A. Frampton
Flow channelling and variability in transit times and tortuosity in a fractured rock model with small scale heterogeneity
Advances in Geosciences
title Flow channelling and variability in transit times and tortuosity in a fractured rock model with small scale heterogeneity
title_full Flow channelling and variability in transit times and tortuosity in a fractured rock model with small scale heterogeneity
title_fullStr Flow channelling and variability in transit times and tortuosity in a fractured rock model with small scale heterogeneity
title_full_unstemmed Flow channelling and variability in transit times and tortuosity in a fractured rock model with small scale heterogeneity
title_short Flow channelling and variability in transit times and tortuosity in a fractured rock model with small scale heterogeneity
title_sort flow channelling and variability in transit times and tortuosity in a fractured rock model with small scale heterogeneity
url https://adgeo.copernicus.org/articles/65/149/2025/adgeo-65-149-2025.pdf
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