@article {264, title = {A field study (Massachusetts, USA) of the factors controlling the depth of groundwater flow systems in crystalline fractured-rock terrain}, journal = {Hydrogeology Journal}, volume = {18}, year = {2010}, note = {Accession Number: 2011-042136; Language: English; Coordinates: N420000N425000W0695500W0714500; Collation: 16; Publication Types: Serial; Updated Code: 201124; Illustration(s): illus. incl. 3 tables, geol. sketch map; Number of References: 58; Reviewed Item: Analytic}, month = {2010/12/01/}, pages = {1839 - 1854}, publisher = {Springer : Berlin - Heidelberg, Germany}, address = {Federal Republic of Germany}, abstract = {Groundwater movement and availability in crystalline and metamorphosed rocks is dominated by the secondary porosity generated through fracturing. The distributions of fractures and fracture zones determine permeable pathways and the productivity of these rocks. Controls on how these distributions vary with depth in the shallow subsurface (<300 m) and their resulting influence on groundwater flow is not well understood. The results of a subsurface study in the Nashoba and Avalon terranes of eastern Massachusetts (USA), which is a region experiencing expanded use of the fractured bedrock as a potable-supply aquifer, are presented. The study logged the distribution of fractures in 17 boreholes, identified flowing fractures, and hydraulically characterized the rock mass intersecting the boreholes. Of all fractures encountered, 2.5\% are hydraulically active. Boreholes show decreasing fracture frequency up to 300 m depth, with hydraulically active fractures showing a similar trend; this restricts topographically driven flow. Borehole temperature profiles corroborate this, with minimal hydrologically altered flow observed in the profiles below 100 m. Results from this study suggest that active flow systems in these geologic settings are shallow and that fracture permeability outside of the influence of large-scale structures will follow a decreasing trend with depth. Copyright 2010 Springer-Verlag}, keywords = {$\#$StaffPubs, aquifers, boreholes, crystalline rocks, eastern Massachusetts, fractured materials, fractures, ground water, hydraulic conductivity, Hydrogeology 21, massachusetts, Nashoba terrane, permeability, porosity, preferential flow, shallow-water environment, substrates, United States}, isbn = {1431217414350157}, url = {http://link.springer.com/article/10.1007\%2Fs10040-010-0640-y}, author = {David F Boutt and Diggins, Patrick and Stephen B Mabee} } @article {266, title = {A method of estimating bulk potential permeability in fractured-rock aquifers using field-derived fracture data and type curves}, journal = {Hydrogeology Journal}, volume = {21}, year = {2013}, note = {Accession Number: 2013-055373; Language: English; Coordinates: N421500N424500W0704500W0714500; Collation: 13; Publication Types: Serial; Updated Code: 201334; Illustration(s): illus. incl. 4 tables, geol. sketch maps; Number of References: 41; Reviewed Item: Analytic}, month = {2013/03/01/}, pages = {357 - 369}, publisher = {Springer : Berlin - Heidelberg, Germany}, address = {Federal Republic of Germany}, abstract = {A method is devised for estimating the potential permeability of fracture networks from attributes of fractures observed in outcrop. The technique, which is intended as a complement to traditional approaches, is based on type curves that represent various combinations of fracture lengths, fracture orientations and proportions (i.e., intensities) of fractures that participate in flow. Numerical models are used to derive the type curves. To account for variations in fracture aperture, a permeability ratio (R) defined as the permeability of a fracture network in a domain divided by the permeability of a single fracture with identical fracture apertures, is used as a dependent variable to derive the type curves. The technique works by determining the point on the type curve that represents the fracture characteristics collected in the field. To test the performance of the technique, permeabilities that were derived from fractured-rock aquifers of eastern Massachusetts (USA) are compared to permeabilities predicted by the technique. Results indicate that permeabilities estimated from type curves are within an order of magnitude of permeabilities derived from field tests. First-order estimates of fracture-network permeability can, therefore, be easily and quickly acquired with this technique before more robust and expensive methods are utilized in the field. Copyright 2012 Springer-Verlag Berlin Heidelberg}, keywords = {$\#$StaffPubs, aquifers, boundary conditions, eastern Massachusetts, fractured materials, fractures, ground water, Hydrogeology 21, massachusetts, Nashoba terrane, naturally fractured reservoirs, numerical models, permeability, prediction, pump tests, simulation, two-dimensional models, United States}, isbn = {1431217414350157}, url = {http://link.springer.com/article/10.1007\%2Fs10040-012-0919-2}, author = {Alex K Manda and Stephen B Mabee and David F Boutt and Cooke, Michele L.} }