TY - Generic T1 - Characterizing fractured crystalline bedrock aquifers using hydrostructural domains in the Nashoba Terrane, eastern Massachusetts T2 - Abstracts with Programs - Geological Society of America Y1 - 2006 A1 - Alex K Manda A1 - Stephen B Mabee A1 - David F Boutt KW - #StaffPubs KW - anisotropy KW - aquifers KW - BEDROCK KW - characterization KW - connectivity KW - crystalline rocks KW - eastern Massachusetts KW - fractures KW - ground water KW - heterogeneity KW - hydraulic conductivity KW - Hydrogeology 21 KW - massachusetts KW - Nashoba terrane KW - outcrops KW - physical properties KW - site exploration KW - United States KW - water wells AB - Fractured crystalline bedrock aquifers are good sources of potable water in many parts of the world. However, siting of highly productive wells in these rock units remains a challenging and expensive task because fracture development at the regional scale is both heterogeneous and anisotropic. Using low cost field data to define units of rock that have similar lithologic and fracture characteristics can significantly reduce time and energy spent on determining areas with better than average aquifer productivity. These physical characteristics that impart a particular hydraulic character on rocks are used to delineate regions with similar hydrologic characteristics called hydrostructural domains (Mackie, 2002). Hydrostructural domains are delineated from fracture characterization data that were collected from 79 outcrops located in the Nashoba Terrane of eastern Massachusetts. Information collected and used to delineate the domains include the number and distribution of fracture sets, types of fractures present or absent, the degree of fracture development, fracture intensity/density, fracture connectivity and rock type. Discrete fracture networks are generated from the fracture characterization data to simulate groundwater flow in the region. Conductivity of particular units is evaluated and compared to results from existing pumping tests obtained from the US Geological Survey. Preliminary results indicate that there is great value in utilizing fracture characteristic data obtained from surface outcrops to predict subsurface groundwater flow characteristics of fractured bedrock aquifers. Water managers, developers and decision makers are eager to know which areas are the most promising for encountering highly conductive zones in the subsurface. Collecting extensive structural data from surface outcrops, although not as accurate as drilling wells, is a cheaper alternative that could provide at least a rough estimate of the hydraulic properties of fractured rocks leading to effective siting of new water wells. Hydrostructural domain maps may pinpoint specific areas that have a high potential for wells to encounter highly conductive zones and could therefore be a powerful tool in transferring information from one site to another without having to repeatedly undertake extensive site characterization. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 38 SN - 00167592 UR - https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_113075.htm IS - 77 N1 - Accession Number: 2007-032741; Conference Name: Geological Society of America, 2006 annual meeting; Philadelphia, PA, United States; Conference Date: 20061022; Language: English; Coden: GAAPBC; Collation: 1; Collation: 25; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200709; Monograph Title: Geological Society of America, 2006 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - JOUR T1 - A method of estimating bulk potential permeability in fractured-rock aquifers using field-derived fracture data and type curves JF - Hydrogeology Journal Y1 - 2013 A1 - Alex K Manda A1 - Stephen B Mabee A1 - David F Boutt A1 - Cooke, Michele L. KW - #StaffPubs KW - aquifers KW - boundary conditions KW - eastern Massachusetts KW - fractured materials KW - fractures KW - ground water KW - Hydrogeology 21 KW - massachusetts KW - Nashoba terrane KW - naturally fractured reservoirs KW - numerical models KW - permeability KW - prediction KW - pump tests KW - simulation KW - two-dimensional models KW - United States AB - 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 PB - Springer : Berlin - Heidelberg, Germany CY - Federal Republic of Germany VL - 21 SN - 1431217414350157 UR - http://link.springer.com/article/10.1007%2Fs10040-012-0919-2 IS - 22 N1 - 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 JO - Hydrogeology Journal ER -