TY - Generic T1 - Factors influencing groundwater inflows in a newly constructed cross-strike tunnel, eastern Massachusetts; 3, Surface vs. subsurface fracture characteristics T2 - Abstracts with Programs - Geological Society of America Y1 - 1999 A1 - Stephen B Mabee A1 - Williams, Katherine W. A1 - Curry, Patrick J. A1 - Hardcastle, Kenneth C. KW - #StaffPubs KW - BEDROCK KW - controls KW - eastern Massachusetts KW - factors KW - fractures KW - ground water KW - Hydrogeology 21 KW - massachusetts KW - measurement KW - movement KW - New England KW - outcrops KW - spatial distribution KW - tunnels KW - United States AB - Major fracture sets (dip >45 degrees ), their geographic distributions (domains), and their characteristics (spacing, trace length, and planarity) were measured in surface outcrops and in a 9 km section of the tunnel (Curry et al., this volume) to determine how well fracture data collected at widely-spaced surface exposures can be extrapolated to a depth of 70 to 90 meters. For the surface fracture data set, fracture sets and domains were determined from 1513 measurements collected at 21 outcrops located within 3 km of the trace of the tunnel. Spacing, trace length, and planarity were determined from scanline measurements (n = 899). For the tunnel data set, 413 fracture measurements were made to determine major sets and domains and a smaller subset (n = 156) was used to estimate fracture characteristics.Five fracture sets (14, 38, 86, 117, and 171) were identified in the outcrops and seven sets (13, 29, 41, 62, 132, 159, and 175) in the tunnel. The 14 and 171 sets correspond well with the 13 and 175 sets in the tunnel. The 38 set observed at the surface includes parts of the 29 and 41 sets in the tunnel. The 86 set does occur in the tunnel but is undersampled because it is aligned with the tunnel. The 62 and 159 sets occur in the tunnel but are not seen at the surface. Although large areas are devoid of outcrops, comparison of surface and subsurface fracture domains indicates that only the 14 and 171 sets show a reasonable overlap with the 13 and 175 domains in the tunnel. These latter sets are the fractures generating most of the groundwater inflow into the tunnel. Median fracture spacing and trace lengths for the 13 and 175 sets in the tunnel are significantly wider and longer than the corresponding 14 and 171 sets at the surface. Fracture planarities showed no significant differences between any of the surface and subsurface fracture sets. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 31 SN - 00167592 IS - 77 N1 - Accession Number: 2001-037340; Conference Name: Geological Society of America, 1999 annual meeting; Denver, CO, United States; Conference Date: 19991025; Language: English; Coden: GAAPBC; Collation: 1; Collation: 348; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200111; Monograph Title: Geological Society of America, 1999 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Factors influencing groundwater inflows in a newly constructed cross-strike tunnel, eastern Massachusetts; 2, Fracture-supported coincident lineaments and subsurface structures T2 - Abstracts with Programs - Geological Society of America Y1 - 1999 A1 - Hardcastle, Kenneth C. A1 - Curry, Patrick J. A1 - Williams, Katherine W. A1 - Stephen B Mabee KW - #StaffPubs KW - BEDROCK KW - controls KW - eastern Massachusetts KW - factors KW - fractures KW - ground water KW - Hydrogeology 21 KW - imagery KW - lineaments KW - massachusetts KW - movement KW - New England KW - outcrops KW - Structural geology 16 KW - tectonics KW - tunnels KW - United States AB - As part of the evaluation of the ability of lineaments to map subsurface structures, the coincident lineaments which intersect the tunnel (Curry et al., this volume), were evaluated to isolate those lineaments considered to be "fracture-supported". By definition, fracture-supported coincident lineaments are those which parallel nearby surface fracture sets, mapped faults, lithologic contacts, and/or primary ductile structures; features which may be influential to subsurface groundwater flow. Of the 37 coincident lineaments delineated on the three scales of imagery studied, approximately 70% are considered to be fracture-supported: 9 of the 13 on the 1:58,000 scale images, 10 of 14 on the 1:80,000, and 8 of 10 on the 1:250,000. However, the general lack of surface exposure precludes high confidence in the assignment of fracture-supported status to most lineaments. Large areas devoid of outcrops necessitated extrapolation of regional, surface fracture patterns (domains) to help define some fracture-supported coincident lineaments. There are two occurrences where fracture-supported coincident lineaments from all three scales overlap and are parallel. One occurrence successfully maps the zone of greatest fracture density and highest groundwater inflow (>560 l/min). The other occurrence maps an area of high fracture density and significant subsurface flow (95 l/min). In addition, one other high flow zone (>190 l/min) is mapped by a fracture-supported coincident lineament from the 1:80,000 scale imagery. However, many subsurface fractures and flow zones (<75 l/min) are not mapped by the coincident lineaments regardless of whether or not they are fracture-supported. When considering all fracture-supported coincident lineaments and parallel subsurface structures, the median flow (13,600 l/day) for the mapped structures is greater than the unmapped structures (6,800 liters/day). However, this difference is only significant at the 60% confidence level.Although the tunnel sections with the greatest fracture density and highest groundwater inflows are successfully mapped by fracture supported coincident lineaments, not all water-bearing zones are delineated. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 31 SN - 00167592 IS - 77 N1 - Accession Number: 2001-037344; Conference Name: Geological Society of America, 1999 annual meeting; Denver, CO, United States; Conference Date: 19991025; Language: English; Coden: GAAPBC; Collation: 1; Collation: 348; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200111; Monograph Title: Geological Society of America, 1999 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Factors influencing groundwater inflows in a newly constructed cross-strike tunnel, eastern Massachusetts; 4, Occurrence and characterization of groundwater inflows T2 - Abstracts with Programs - Geological Society of America Y1 - 1999 A1 - Williams, Katherine W. A1 - Stephen B Mabee A1 - Hardcastle, Kenneth C. A1 - Curry, Patrick J. KW - #StaffPubs KW - BEDROCK KW - boreholes KW - characterization KW - design KW - discharge KW - eastern Massachusetts KW - flows KW - fractures KW - Framingham Quadrangle KW - ground water KW - Hydrogeology 21 KW - massachusetts KW - movement KW - Natik Quadrangle KW - occurrence KW - outcrops KW - surface water KW - topography KW - tunnels KW - United States AB - All occurrences of groundwater inflows in a 9 km long, 5-m diameter section of tunnel, 70 to 90 m below grade, were compared with subsurface fracture density, bedrock topography, surface topography, type of surficial deposits, proximity to surface water bodies, and the geographic distribution (domains; Mabee et al., this volume) of surface and subsurface fractures. Subsurface fracture density was calculated for the 320 fractures (through-going fractures) that intersect the entire circumference of the tunnel. Bedrock topography was determined using bore hole data collected during the design phase of the tunnel project. Surface topography is from 1:25,000 scale topographic maps and surficial geology is based on maps of the Framingham and Natick Quadrangles. Seven surface water bodies, primarily brooks and rivers, overlie the tunnel. Five surface fracture domains are based on 1513 fracture measurements collected from 21 outcrops within 3 km of the tunnel. In the tunnel, 413 fractures (all fractures, dips>45 degrees ) comprise seven subsurface fracture domains. High groundwater inflows generally correlate with areas of high subsurface fracture density and where four or more subsurface fracture domains overlap. In addition, high groundwater inflows are also generally located near surface water bodies and below permeable surficial deposits and topographic depressions, especially those with corresponding lows in the bedrock surface. Moreover, subsurface structures which correlate with prominent surface fracture domains produce the highest volume of groundwater inflow. However, not all tunnel sections exhibiting high fracture density and overlapping fracture domains exhibit high groundwater inflows. Also, there is no correlation between areas where two or more surface fracture domains overlap and the volume of groundwater discharging to the tunnel. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 31 SN - 00167592 IS - 77 N1 - Accession Number: 2001-037345; Conference Name: Geological Society of America, 1999 annual meeting; Denver, CO, United States; Conference Date: 19991025; Language: English; Coden: GAAPBC; Collation: 1; Collation: 348; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200111; Monograph Title: Geological Society of America, 1999 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Factors influencing groundwater inflows in a newly constructed cross-strike tunnel, eastern Massachusetts; 1, Lineaments and subsurface structures T2 - Abstracts with Programs - Geological Society of America Y1 - 1999 A1 - Curry, Patrick J. A1 - Hardcastle, Kenneth C. A1 - Stephen B Mabee A1 - Williams, Katherine W. KW - #StaffPubs KW - BEDROCK KW - eastern Massachusetts KW - fractures KW - geophysical surveys KW - ground water KW - Hydrogeology 21 KW - lineaments KW - massachusetts KW - metamorphic rocks KW - movement KW - New England KW - remote sensing KW - SLAR KW - strike KW - surveys KW - tectonics KW - tunnels KW - United States AB - Lineaments derived from three platforms; 1:250,000 Side-Looking Airborne Radar (SLAR) images, 1:58,000 Color Infrared (CIR) and 1:80,000 Black and White aerial photographs (BW), were compared to water bearing structures (n = 99) within a 9 km, 70 to 90 meter deep, east-west tunnel being constructed in eastern Massachusetts. Lineaments were drawn by three observers during two independent trials to produce 18 sets of lineaments (n = 9137) covering approximately 1,000 km (super 2) centered over the tunnel. All lineaments for each platform were compared. Three or more overlapping lineaments (azimuths within 5 degrees and within 1 mm at the scale of the imagery) define a single coincident lineament. This analysis generated three sets of coincident lineaments (n = 794), of these 37 cross the tunnel. Buffers were placed around the coincident lineaments at a distance of 1 mm from the center of the lineament at the scale of the platform (e.g. 250 m for the SLAR image). The Mann-Whitney U test was used to determine if the median flow from all tunnel structures which underlie the lineament buffer zones is significantly greater than that of all structures outside of the buffer zones. Results indicate that median flow (11,000 l/day) from structures located within the buffer zones of the BW are significantly greater at the 90% confidence level than the median flow (5,500 l/day) of structures located outside the buffer zones. No significant differences in flow were found for the other two platforms. Subsurface structures that parallel coincident lineaments (all platforms) and occur within the buffer zones have higher median flow (10,500 l/day) than those structures outside the buffer zones (6,600 l/day). However, this difference is significant at the 70% confidence level. These results suggest that, in some instances, a thorough lineament analysis can predict water-bearing subsurface structures in poorly exposed, glaciated, metamorphic terrain that has a high degree of suburban development. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 31 SN - 00167592 IS - 77 N1 - Accession Number: 2001-037333; Conference Name: Geological Society of America, 1999 annual meeting; Denver, CO, United States; Conference Date: 19991025; Language: English; Coden: GAAPBC; Collation: 2; Collation: 347-348; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200111; Monograph Title: Geological Society of America, 1999 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Fracture characterization; valuable inputs for modeling groundwater flow in fractured bedrock T2 - Abstracts with Programs - Geological Society of America Y1 - 1996 A1 - Stephen B Mabee A1 - Hardcastle, Kenneth C. KW - #StaffPubs KW - BEDROCK KW - boreholes KW - California KW - discontinuities KW - experimental studies KW - field studies KW - fractured materials KW - fractures KW - ground water KW - Hydrogeology 21 KW - Madera County California KW - models KW - movement KW - observation wells KW - Raymond California KW - site exploration KW - spatial distribution KW - transmissivity KW - United States KW - wells JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 28 SN - 00167592 IS - 33 N1 - Accession Number: 1996-065028; Conference Name: Geological Society of America, Northeastern Section, 31st annual meeting; Buffalo, NY, United States; Conference Date: 19960321; Language: English; Coordinates: N364500N374500W1190100W1203800; Coden: GAAPBC; Collation: 1; Collation: 77; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 199620; Monograph Title: Geological Society of America, Northeastern Section, 31st annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER -