@proceedings {272,
	title = {Characterizing fractured crystalline bedrock aquifers using hydrostructural domains in the Nashoba Terrane, eastern Massachusetts},
	volume = {38},
	year = {2006},
	note = {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},
	month = {2006/10/01/},
	pages = {25 - 25},
	publisher = {Geological Society of America (GSA) : Boulder, CO, United States},
	address = {United States},
	abstract = {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.},
	keywords = {$\#$StaffPubs, anisotropy, aquifers, BEDROCK, characterization, connectivity, crystalline rocks, eastern Massachusetts, fractures, ground water, heterogeneity, hydraulic conductivity, Hydrogeology 21, massachusetts, Nashoba terrane, outcrops, physical properties, site exploration, United States, water wells},
	isbn = {00167592},
	url = {https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_113075.htm},
	author = {Alex K Manda and Stephen B Mabee and David F Boutt}
}
@proceedings {302,
	title = {Implications of diurnal river fluctuations on mass transport in a valley-fill aquifer},
	volume = {38},
	year = {2006},
	note = {Accession Number: 2010-061334; Conference Name: Geological Society of America, 2006 annual meeting; Philadelphia, PA, United States; Conference Date: 20061022; Language: English; Coden: GAAPBC; Collation: 1; Collation: 468; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201034; Monograph Title: Geological Society of America, 2006 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic},
	month = {2006/10/01/},
	pages = {468 - 468},
	publisher = {Geological Society of America (GSA) : Boulder, CO, United States},
	address = {United States},
	abstract = {Aquifers located in isolated stratified drift deposits in the northeastern portion of the US are extremely fragile and important groundwater resources. These aquifers, when restricted to bedrock valleys, are often strongly coupled to significant surface water drainage systems. In northwestern Massachusetts, surface water associated with the Deerfield River watershed is highly regulated by dams to protect against flooding and to generate hydroelectric power. Regular releases of water from these dams cause diurnal fluctuations in river stage. In a previous study performed by the USGS, measurements from two clusters of wells show a significant response to river stage fluctuations in the aquifer. Fluctuations in river stage and resulting changes in head levels in the aquifer cause a switch from a losing to a gaining stream. The flow reversals have implications for mass transport and nutrient cycling within the hyporheic zone. In this paper we investigate the physical hydrologic controls on mass transport in the shallow aquifer. Using a coupled groundwater flow and transport code, we built a quasi three dimensional transient numerical model to approximate the head changes in the aquifer caused by the stage fluctuations in the river. Flow velocities and residence times were estimated in the aquifer for a variety of flow conditions. The mixing process driven by the aquifer head changes were quantified in the proximity of the hyporheic zone and shown to significantly influence both vertical and horizontal flow velocities in a region close to the stream-aquifer boundary. The diurnal river stage changes also appear to influence farfield hydrologic conditions and potentially hydrologically isolate the river and hyporheic zone. To further investigate these mixing processes we applied a mass transport code with conservative tracers to the aquifer. Fluctuation of the river stage combined with the heterogeneous nature of the aquifer creates a pumping mechanism that creates excess mixing within shallow portions of the aquifer. Aquifer dispersivity and molecular diffusion both contribute to the anomalous mixing modeled in the shallow aquifer. Mixing driven by stream stage changes has important implications for nutrient cycling as well as contaminant transport in the shallow aquifer.},
	keywords = {$\#$StaffPubs, aquifers, BEDROCK, clastic sediments, controls, diffusion, diurnal variations, drainage, drift, Eastern U.S., Environmental geology 22, floods, fluctuations, geochemical cycle, geologic hazards, ground water, measurement, mixing, models, Northeastern U.S., numerical models, nutrients, pollution, processes, pumping, quantitative analysis, residence time, sediments, shallow aquifers, surface water, three-dimensional models, tracers, transport, United States, valleys, water pollution, water resources, water wells},
	isbn = {00167592},
	url = {https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_115285.htm},
	author = {Brandon J Fleming and David F Boutt and Stephen B Mabee}
}
@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 {315,
	title = {Implications of anthropogenic river stage fluctuations on mass transport in a valley fill aquifer},
	journal = {Water Resources Research},
	volume = {45},
	year = {2009},
	month = {2009/01/01/},
	pages = {@CitationW04427 - @CitationW04427},
	publisher = {American Geophysical Union : Washington, DC, United States},
	abstract = {In humid regions a strong coupling between surface water features and groundwater systems may exist. In these environments the exchange of water and solute depends primarily on the hydraulic gradient between the reservoirs. We hypothesize that daily changes in river stage associated with anthropogenic water releases (such as those from a hydroelectric dam) cause anomalous mixing in the near-stream environment by creating large hydraulic head gradients between the stream and adjacent aquifer. We present field observations of hydraulic gradient reversals in a shallow aquifer. Important physical processes observed in the field are explicitly reproduced in a physically based two-dimensional numerical model of groundwater flow coupled to a simplistic surface water boundary condition. Mass transport simulations of a conservative solute introduced into the surface water are performed and examined relative to a stream condition without stage fluctuations. Simulations of 20 d for both fluctuating river stage and fixed high river stage show that more mass is introduced into the aquifer from the stream in the oscillating case even though the net water flux is zero. Enhanced transport by mechanical dispersion leads to mass being driven away from the hydraulic zone of influence of the river. The modification of local hydraulic gradients is likely to be important for understanding dissolved mass transport in near-stream aquifer environments and can influence exchange zone processes under conditions of high-frequency stream stage changes.},
	keywords = {$\#$Hydro, $\#$WaterResources, aquifers, boundary conditions, Charlemont, Deerfield River basin, fluctuations, fluvial features, Franklin County Massachusetts, ground water, human activity, Hydrogeology 21, hydrology, massachusetts, numerical models, preferential flow, rivers, shallow aquifers, streams, surface water, transport, two-dimensional models, United States, valleys},
	isbn = {0043139719447973},
	url = {http://onlinelibrary.wiley.com/doi/10.1029/2007WR006526/full},
	author = {David F Boutt and Brandon J Fleming}
}
@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.}
}
