Estimating regional-scale fractured bedrock hydraulic conductivity using discrete fracture network (DFN) modeling

Voeckler, Hendrik Maximilian; Allen, D. M.

doi:10.1007/s10040-012-0858-y

Cited by 33 publications

(26 citation statements)

References 33 publications

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“…In this study, we used groundwater springs as good indications of groundwater availability for groundwater potential mapping. This is because in the study area, as in most other mountainous environments, few hydrogeological and hydrological data (i.e., groundwater levels, well yields, and stream discharge) are available due to a lack of piezometric wells in these high-elevation settings [35]. The methodology used in this research comprised several steps.…”

Section: Methodsmentioning

confidence: 99%

A Modeling Comparison of Groundwater Potential Mapping in a Mountain Bedrock Aquifer: QUEST, GARP, and RF Models

Moghaddam

Rahmati

Haghizadeh

et al. 2020

Water

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In some arid regions, groundwater is the only source of water for human needs, so understanding groundwater potential is essential to ensure its sustainable use. In this study, three machine learning models (Genetic Algorithm for Rule-Set Production (GARP), Quick Unbiased Efficient Statistical Tree (QUEST), and Random Forest (RF)) were applied and verified for spatial prediction of groundwater in a mountain bedrock aquifer in Piranshahr Watershed, Iran. A spring location dataset consisting of 141 springs was prepared by field surveys, and from this three different sample datasets (S1–S3) were randomly generated (70% for training and 30% for validation). A total of 10 groundwater conditioning factors were prepared for modeling, namely slope percent, relative slope position (RSP), plan curvature, altitude, drainage density, slope aspect, topographic wetness index (TWI), terrain ruggedness index (TRI), land use, and lithology. The area under the receiver operating characteristic curve (AUC) and true skill statistic (TSS) were used to evaluate the accuracy of models. The results indicated that all models had excellent goodness-of-fit and predictive performance, but that RF (AUCmean = 0.995, TSSmean = 0.89) and GARP (AUCmean = 0.957, TSSmean = 0.82) outperformed QUEST (AUCmean = 0.949, TSSmean = 0.74). In robustness analysis, RF was slightly more sensitive than GARP and QUEST, making it necessary to consider several random partitioning options for preparing training and validation groups. The outcomes of this study can be useful in sustainable management of groundwater resources in the study region.

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Section: Methodsmentioning

confidence: 99%

A Modeling Comparison of Groundwater Potential Mapping in a Mountain Bedrock Aquifer: QUEST, GARP, and RF Models

Moghaddam

Rahmati

Haghizadeh

et al. 2020

Water

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“…The multiple geological factors potentially controlling mountain‐block K are discussed by Wilson and Guan (), and Welch and Allen () present a compilation of fractured‐bedrock K measurements and estimates for mountainous terrain. In general, K decreases with depth in fractured rocks owing to the decreasing influence of weathering (Worthington et al, ) and the decreasing aperture and number of open fractures and pores due to increasing overburden loads and mineral precipitation (Manning & Ingebritsen, ; Saar & Manga, ; Stober & Bucher, ; St. Clair et al, ; Voeckler & Allen, ). As reviewed in detail in Welch and Allen () and Manning and Caine (), multiple lines of evidence presented in pre‐ and post‐2004 studies have contributed to the development of a now widely invoked general conceptual model for mountain groundwater flow systems, in which a higher‐K “active” zone (the aquifer) overlies a deep low‐K zone (relatively impermeable bedrock).…”

Section: Mbr Reviewmentioning

confidence: 99%

Mountain‐Block Recharge: A Review of Current Understanding

Markovich

Manning

Condon

et al. 2019

Water Resources Research

121

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Mountain‐block recharge (MBR) is the subsurface inflow of groundwater to lowland aquifers from adjacent mountains. MBR can be a major component of recharge but remains difficult to characterize and quantify due to limited hydrogeologic, climatic, and other data in the mountain block and at the mountain front. The number of MBR‐related studies has increased dramatically in the 15 years since the last review of the topic was conducted by Wilson and Guan (2004), generating important advancements. We review this recent body of literature, summarize current understanding of factors controlling MBR, and provide recommendations for future research priorities. Prior to 2004, most MBR studies were performed in the southwestern United States. Since then, numerous studies have detected and quantified MBR in basins around the world, typically estimating MBR to be 5–50% of basin‐fill aquifer recharge. Theoretical studies using generic numerical modeling domains have revealed fundamental hydrogeologic and topographic controls on the amount of MBR and where it originates within the mountain block. Several mountain‐focused hydrogeologic studies have confirmed the widespread existence of mountain bedrock aquifers hosting considerable groundwater flow and, in some cases, identified the occurrence of interbasin flow leaving headwater catchments in the subsurface—both of which are required for MBR to occur. Future MBR research should focus on the collection of high‐priority data (e.g., subsurface data near the mountain front and within the mountain block) and the development of sophisticated coupled models calibrated to multiple data types to best constrain MBR and predict how it may change in response to climate warming.

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“…Equivalent porous media approaches for non-karstic fractured bedrock springs are also reported in the literature (e.g., Farlin et al, 2013;Swanson et al, 2006;Swanson and Bahr, 2004). In contrast to continuum and multi-continua approaches, discrete fracture network models in sedimentary and crystalline rock aquifer settings can be used to investigate the effects of individual fracture features on groundwater flow incorporating parameters including aperture, spacing, density and length (Voeckler and Allen, 2012;Levison and Novakowski, 2012;Blessent et al, 2011;Gleeson et al, 2009;Berkowitz, 2002).…”

Section: Introductionmentioning

confidence: 99%

Modeling low-flow bedrock springs providing ecological habitats with climate change scenarios

Levison

Larocque

Ouellet

2014

Journal of Hydrology

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Groundwater discharge areas, including low-flow bedrock aquifer springs, are ecologically important and can be impacted by climate change. The development of and results from a groundwater modeling study simulating fractured bedrock spring flow are presented. This was conducted to produce hydrological data for an ecohydrological study of an endangered species, Allegheny Mountain Dusky Salamanders (Desmognathus ochrophaeus), in southern Quebec, Canada. The groundwater modeling approach in terms of scale and complexity was strongly driven by the need to produce hydrological data for the related ecohydrological modeling. Flows at four springs at different elevations were simulated for recent past conditions (2006-2010) and for reference (1971-2000) and future (2041-2070) periods using precipitation and temperature data from ten climate scenarios. Statistical analyses of spring flow parameters including activity periods and duration of flow were conducted. Flow rates for the four simulated springs, located at different elevations, are predicted to increase between 2% and 46% and will be active (flowing) 1% to 2% longer in the future. A significant change (predominantly an increase) looking at the seasonality of the number of active days occurs in the winter (2% to 4.9%) and spring seasons (-0.6% to 6.5%). Greatest flow rates were produced from springs at elevations where sub-horizontal fractures intersect the ground surface. These results suggest an intensification of the spring activity at the study site in context of climate change by 2050, which provides a positive habitat outlook for the endangered salamanders residing in the springs for the future.

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Estimating regional-scale fractured bedrock hydraulic conductivity using discrete fracture network (DFN) modeling

Cited by 33 publications

References 33 publications

A Modeling Comparison of Groundwater Potential Mapping in a Mountain Bedrock Aquifer: QUEST, GARP, and RF Models

A Modeling Comparison of Groundwater Potential Mapping in a Mountain Bedrock Aquifer: QUEST, GARP, and RF Models

Mountain‐Block Recharge: A Review of Current Understanding

Modeling low-flow bedrock springs providing ecological habitats with climate change scenarios

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