Prepared in cooperation with the U.S. Environmental Protection Agency

Geophysical Log Analysis of Selected Test and Residential 

Wells at the Shenandoah Road National Superfund Site, 

East Fishkill, Dutchess County, New York

Scientific Investigations Report 2014-5228

U.S. Department of the Interior

U.S. Geological Survey
Cover. Drilling well SRMW-18D at the Shenandoah Road National Superfund Site. Geophysical logging of adjacent well SRMW-18B is 

being conducted during air rotary drilling of SRMW-18D. 
Geophysical Log Analysis of Selected Test 

and Residential Wells at the Shenandoah 

Road National Superfund Site, East Fishkill, 

Dutchess County, New York

By Richard J. Reynolds, J. Alton Anderson, and John H. Williams

Prepared in cooperation with the U.S. Environmental Protection Agency

Scientific Investigations Report 2014-5228

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2015

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Suggested citation:

Reynolds, R.J., Anderson, J.A., and Williams, J.H., 2015, Geophysical log analysis of selected test and residential 

wells at the Shenandoah Road National Superfund Site, East Fishkill, Dutchess County, New York: U.S. Geological 

Survey Scientific Investigations Report 2014–5228, 30 p., http://dx.doi.org/10.3133/sir20145228

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20145228
iii

Acknowledgments

The authors thank Damian Duda of the U.S. Environmental Protection Agency, Region 2, and 

Grant Anderson of the U.S. Army Corps of Engineers for supporting the U.S. Geological Survey 

technical role in this investigation. Craig Robertson, Dorothy Bergmann, and Mitch Ruchin of 

Groundwater Sciences Corporation and their staff are thanked for their assistance in the geophysical logging operations.

v

Contents

Abstract ..........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Description of Study Area ...................................................................................................................2

Remedial Investigation of the Shenandoah Road National Superfund Site ...............................2

Purpose and Scope ..............................................................................................................................4

Bedrock Geology............................................................................................................................................4

Precambrian Gneiss.............................................................................................................................4

Wappinger Group..................................................................................................................................4

Poughquag Quartzite...................................................................................................................5

Stissing Dolomite .........................................................................................................................5

Pine Plains Formation .................................................................................................................5

Briarcliff Dolomite........................................................................................................................5

Structural Geology.........................................................................................................................................5

Surficial Geology............................................................................................................................................6

Shenandoah Moraine ..........................................................................................................................6

Outwash Sand and Gravel...................................................................................................................7

Description of Wells ......................................................................................................................................7

Test Wells...............................................................................................................................................7

Residential Wells ..................................................................................................................................7

Data Collection ..............................................................................................................................................7

Drilling Logs for Test Wells..................................................................................................................7

Geophysical Logs................................................................................................................................12

Single-Well Aquifer Tests..................................................................................................................13

Geophysical Log Analysis ..........................................................................................................................13

Lithology ...............................................................................................................................................13

Structural Features.............................................................................................................................14

Bedrock Fabric...........................................................................................................................14

Fractures .....................................................................................................................................14

Flow Zones...........................................................................................................................................14

Distribution of Flow Zones and Wellbore Flow..............................................................................14

Estimates of Total Wellbore Transmissivity ....................................................................................15

Estimates of Flow-Zone Transmissivity and Head.........................................................................15

Online Geophysical Log Archive ...............................................................................................................19

Summary........................................................................................................................................................19

Selected References...................................................................................................................................20

Appendix 1. Geophysical Log Analysis of Three Selected Wells at the Shenandoah Road 

National Superfund Site, Dutchess County, N.Y........................................................................23

Explanation of Geophysical Log Column Headings ......................................................................30
vi

Figures

1. Map showing location of logged wells at the Shenandoah Road National

Superfund Site, Dutchess County, N.Y. .....................................................................................3

2. Log-Log plot of specific capacity at 30 minutes versus transmissivity for logged

wells at the Shenandoah Road National Superfund Site, Dutchess County, N.Y. ...........15

3. Conceptual model of two flow zones in a well with heads under ambient and

pumped conditions .....................................................................................................................18

4. Graph showing frequency distribution of estimated transmissivity of flow zones

penetrated by wells at the Shenandoah Road National Superfund Site, Dutchess

County, N.Y. ..................................................................................................................................18

5. Graph showing depths of individual fracture zones versus estimated fracture zone

transmissivity for wells logged at the Shenandoah Road National Superfund Site,

Dutchess County, N.Y. ................................................................................................................19

6. Graph showing comparison of estimated hydraulic-head difference to measured

hydraulic-head difference for flow zones in logged wells at the Shenandoah Road

National Superfund Site, Dutchess County, N.Y. ...................................................................19

Tables

1. Location, construction, and water-level information for selected wells at the

Shenandoah Road National Superfund Site, Dutchess County, N.Y....................................8

2. Types of geophysical logs collected from selected wells at the Shenandoah Road

National Superfund Site, Dutchess County, N.Y....................................................................10

3. Ambient water levels, pumping rates, specific capacities, and transmissivities

for selected wells at the Shenandoah Road National Superfund Site, 

Dutchess County, N.Y. ................................................................................................................16
vii

Conversion Factors and Datum

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2

)

acre 0.4047 hectare (ha)

Volume

gallon (gal) 3.785 liter (L) 

Flow rate

gallon per minute (gal/min) 0.06309 liter per second (L/s)

Specific capacity

gallon per minute per foot 

[(gal/min)/ft)]

0.2070 liter per second per meter [(L/s)/m]

Transmissivity*

foot squared per day (ft2

/d) 0.09290 meter squared per day (m2/d) 

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

Horizontal coordinate information is referenced to North American Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.

*Transmissivity: The standard unit for transmissivity is cubic foot per day per square foot times 

foot of aquifer thickness [(ft3/d)/ft2]ft. In this report, the mathematically reduced form, foot 

squared per day (ft2/d), is used for convenience.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 

25 °C).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) 

or micrograms per liter (μg/L).
viii

Abbreviations

AOC Administrative Order on Consent

ATV acoustic televiewer

BP before present

EPA U.S. Environmental Protection Agency

ESI Expanded Site Inspection

GSC Groundwater Sciences Corporation

HPFM heat-pulse flow meter

MCL maximum contaminant levels

NYSDEC New York State Department of Environmental Conservation

NYSDOH New York State Department of Health

OTV optical televiewer

PCE tetrachloroethene

POET point-of-entry-treatment 

ppb parts per billion

TCE trichloroethane

PRP potentially responsible party

RI/FS Remedial Investigation/Feasibility Study

USGS U.S. Geological Survey

VOC volatile organic compound
Geophysical Log Analysis of Selected Test and Residential 

Wells at the Shenandoah Road National Superfund Site, 

East Fishkill, Dutchess County, New York

By Richard J. Reynolds, J. Alton Anderson, and John H. Williams

Abstract 

The U.S. Geological Survey collected and analyzed 

geophysical logs from 20 test wells and 23 residential wells at 

the Shenandoah Road National Superfund Site in East Fishkill, 

New York, from 2006 through 2010 as part of an Interagency 

Agreement to provide hydrogeologic technical support to the 

U.S. Environmental Protection Agency, Region 2. The geophysical logs collected include caliper, gamma, acoustic and 

optical televiewer, deviation, electromagnetic-induction, magnetic-susceptibility, fluid-property, and flow under ambient and 

pumped conditions. The geophysical logs were analyzed along 

with single-well aquifer test data and drilling logs to characterize the lithology, fabric, fractures, and flow zones penetrated 

by the wells. The results of the geophysical log analysis were 

used as part of the hydrogeologic characterization of the site 

and in the design of discrete-zone monitoring installations in 

the test wells and selected residential wells.

Most of the logged test and residential wells penetrated 

gneiss of the Hudson Highlands Complex or dolostones in 

the Wappinger Group, and some wells penetrated both the 

dolostone and gneiss. The bedrock fabric reflects the regional 

northeast-southwest structural trend, as well as localized folding, and includes foliation in the gneiss and bedding in the 

dolostone. Many fractures were oriented along the bedrock 

fabric, whereas others were orthogonal to the fabric.

Total wellbore transmissivity of the wells was estimated 

from short-term, single-well aquifer test data through the use 

of the Cooper-Jacob analytical solution. An empirical relation was established to estimate total wellbore transmissivity 

from specific-capacity data for wells with insufficient transient 

drawdown measurements. Wellbore transmissivity estimates 

ranged from 0.36 to 370 feet squared per day (ft2

/d), whereas 

specific capacities ranged from 0.03 to 2.1 gallons per minute 

per foot ((gal/min)/ft).

Transmissivity and hydraulic heads of individual fracture 

zones were estimated from the total wellbore transmissivity and flow logs through use of an analytical model based 

on the Thiem equation. The model-estimated transmissivity 

of 95 fracture zones delineated in the 43 wells ranged from 

0.25 to 340 ft2

/d, with a median value of 6.7 ft2/d. The difference between model-estimated fracture-zone heads and the 

composite heads in each well ranged from less 0.01 to more 

than 10 feet (ft). Flow-log analysis generally provided an 

order of magnitude estimate for the fracture-zone hydraulichead difference on the basis of a comparison of estimated and 

measured values.

The geophysical logs and their analyses are available for 

display and download from the U.S. Geological Survey, New 

York Water Science Center, online geophysical log archive 

(http://ny.water.usgs.gov/maps/geologs/) in LAS (Log ASCII 

Standard), PDF, and WellCad formats.

Introduction

In 2001, the U.S Environmental Protection Agency (EPA) 

Region 2 requested the U.S. Geological Survey (USGS) to 

assist with the hydrogeologic assessment of the Shenandoah 

Road National Superfund Site in the Town of East Fishkill in 

Dutchess County, New York. This site is located on the ridge 

of Shenandoah Mountain, and past site activities have resulted 

in the contamination of more than 100 residential wells with 

volatile organic compounds, principally tetrachloroethene 

(PCE) and trichloroethane (TCE). As part of an initial effort, 

the USGS provided a background summary of both bedrock and surficial geology of the area (R.J. Reynolds, U.S. 

Geological Survey, written commun., 2001; on file at USGS 

Water Science Center, Troy, New York), well data, and ambient water-quality data. USGS staff reviewed workplans and 

reports prepared by consulting firms and provided technical 

commentary and suggestions, where appropriate.

Results of analysis of initial groundwater samples collected from April to August 2000 by the New York State 

Department of Health (NYSDOH) and EPA were used to 

identify 59 residential wells that were contaminated with 

PCE and other volatile organic compounds in concentrations 

greater than the Federal and New York State maximum contaminant levels (MCL) of 0.005 mg/L. A total of 230 homes 

in the affected area were sampled at least once, and a pattern 
2 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York

of contamination emerged from subsequent sampling events 

that revealed the highest levels of contamination [1,600 parts 

per billion (ppb) in a residential well] nearest the source, with 

overall levels of contamination decreasing with distance from 

the source. Subsequently, EPA installed point-of-entry-treatment (POET) systems in 105 of the affected homes.

Field work conducted by the New York State Department of Environmental Conservation (NYSDEC) and EPA on 

Shenandoah Mountain in October 2000 revealed the existence of a buried septic tank at a small industrial facility that 

contained extremely high levels of PCE. The facility on East 

Hook Cross Road, consisted of a small building that reportedly was used for the repair and cleaning of microchip racks 

used in computer chip manufacturing from the late 1960s 

through the mid-1970s. The septic system was filled with 

three layers of material: an upper liquid layer, a middle sludge 

layer, and a lower oily layer. All layers were contaminated 

with PCE; the lower oily layer was approximately 93 percent 

PCE (934,000,000 ppb), whereas the middle layer had levels 

of up to 71,000,000 ppb PCE (U.S. Environmental Protection 

Agency, 2001). Although the chip-rack cleaning operation 

ceased in the mid-1970s, the septic system at this property 

had remained in limited use since then and provided a continuing source of groundwater contamination for approximately 30 years. On November 7, 2000, EPA removed ten 

55-gallon drums of liquid from the septic system to prevent 

further overflow into the soil. This septic system is believed 

to be the source of the groundwater contamination at the site 

(U.S. Environmental Protection Agency, 2001).

Description of Study Area

The study area is located in the Town of East Fishkill 

in southern Dutchess County, New York (fig. 1), and consists of residential subdivisions intermingled with extensive 

farmland and patches of woodlands. The homes in the area 

previously used private residential wells for potable water 

supply and septic systems for sanitary wastewater disposal. 

The study area is underlain by unconsolidated Pleistocene 

glacial deposits that overlie complexly folded, highly fractured and weathered dolostones that underlie the valleys, and 

up-thrusted fault blocks of the Precambrian gneissic basement 

rock that form the mountain ridges. The contamination site 

is located on the northeastern end of Shenandoah Mountain, 

which forms a ridge that is elongated in a northeast/southwest 

direction (fig. 1). The Precambrian gneiss that forms Shenandoah Mountain is overlain with a thin layer of glacial till. The 

adjacent valley to the east and north is underlain by dolostones 

and quartzite of the Cambrian/Ordovician-age Wappinger 

Group, which is in turn overlain by till, alluvium, and lacustrine sediments of variable thickness.

Most of the contaminated wells are located immediately 

adjacent to and topographically lower than the source site 

and continue into the valley in a predominantly northeast/

east direction. Groundwater is the sole source of water in 

the affected area. There are two aquifer types of concern in 

the area: a surficial aquifer of unconsolidated deposits and 

bedrock aquifers consisting of gneiss and dolostone. Results 

from residential well sampling conducted by NYDSOH and 

EPA from April through September 2000 indicate that these 

aquifers are interconnected. Residential wells on Shenandoah 

Mountain are completed in the gneiss, whereas wells in the 

valley are predominantly completed in the dolostone.

Remedial Investigation of the Shenandoah Road 

National Superfund Site

In November and early December 2000, EPA excavated the septic tank associated with the facility at 7 East 

Hook Cross Road and removed its contents for transportation and off-site treatment and disposal. EPA also excavated 

contaminated soil associated with the septic tank, which was 

temporarily stockpiled at the site. On the basis of results from 

field screening and analysis of post-excavation soil samples 

collected by EPA, it was evident that high levels of PCE still 

remained in the soil beneath the facility. As a result, it was 

necessary for EPA to demolish the facility prior to excavation 

of the underlying contaminated soil. During excavation of 

the contaminated soil associated with the former septic tank, 

two additional PCE disposal areas were discovered. Approximately 4,800 tons of contaminated soil associated with the 

former septic tank and the two PCE disposal areas were staged 

at the site and removed for off-site disposal by a potentially 

responsible party (PRP) in August 2001. Also, in August 2001, 

EPA discovered a buried “acid pit” behind the former 7 East 

Hook Cross Road facility. Field sampling results revealed high 

concentrations of PCE in the soil surrounding the acid pit, and 

EPA directed a PRP for the site to excavate the contaminated 

soil. Excavation activities associated with the former acid pit 

and off-site disposal of approximately 2,000 tons of contaminated soil were completed in January 2002.

In January 2001, EPA began an Expanded Site Inspection 

(ESI) in order to collect additional data and further delineate 

the extent of groundwater contamination. As part of the ESI, 

EPA’s contractors conducted a limited bedrock investigation that included the installation of monitoring wells, borehole geophysics, and fracture trace analysis. EPA added the 

Shenandoah Road Groundwater Contamination Site in the 

town of East Fishkill, New York, (Dutchess County) to the 

Superfund National Priorities List on June 14, 2001 (U.S. 

Environmental Protection Agency, 2001).

 In May 2001, EPA signed an Administrative Order on 

Consent (AOC) with International Business Machines (IBM). 

Under the AOC, IBM assumed responsibility for the completion of the soil removal action at the 7 East Hook Cross Road 

source area started by EPA, as well as continued maintenance 

of the POET systems in the affected homes. Also under the 

terms of the AOC, engineering consulting firms working for 

IBM evaluated alternate water-supply sources. IBM agreed 

to implement EPA’s selected response action, including 
Introduction 3

Figure 1. Location of logged wells at the Shenandoah Road National Superfund Site, Dutchess County, N.Y.

3267

3266

3265

3264

3263

3262

3261

3260

3259

3257 3258

3256

3255 3254

3253

3251

3249

3247

3246

3245

3244

3242

3241

3235

3232

3231

3230

3229

3228

3227

3226

3225 3252

3248

3234

Base from U.S. Geological Survey, 1:24,000 series, Hopewell Junction, NY (1957)

Interstate 84

Taconic State Parkway

Hosner Mountain

Shenandoah Mountain

Shenandoah Moraine

EAST HOOK CROSS ROAD

SHENANDOAH ROAD

78° 76° 74°

42°

44°

Long Island

0 50 100 MILES

0 50 100 KILOMETERS

DUTCHESS

COUNTY

PUTNAM

COUNTY

Site

Shenandoah Road

National Superfund

site

3233

3236

3237

3238

3239

3240

Residential well and

county number

Test well and county number

EXPLANATION

3243

3250

41°31'30"

41°32'

73°47'30" 73°47'
4 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York

installation of the transmission piping and distribution system, 

and perform initial groundwater investigations in and around 

the site.

In August 2004, EPA issued a Decision Document, by 

which the Town of Fishkill Municipal Water Supply was 

selected as the permanent water supply for the affected 

residents at the site; the water supplier was chosen from the 

various previously identified water-supply alternatives. Under 

a second AOC with EPA, IBM has performed the Remedial 

Investigation/Feasibility Study (RI/FS). The Remedial Investigation involves gathering the groundwater, surface-water, 

and hydrogeologic data needed to determine the nature and 

extent of contamination at the site, whereas the Feasibility 

Study involves evaluating appropriate alternatives to remediate the contamination.

Several rounds of residential well sampling by the RI/FS 

contractor, Groundwater Sciences Corporation (GSC), have 

been conducted to document the extent of groundwater contamination from the source at this site. Water samples from 59 

residential wells had concentrations that exceeded the MCL 

of 0.005 mg/L for PCE. Water samples from 20 wells had 

concentrations that exceeded the EPA Removal Action Level 

of 70 ppb of PCE.

During 2006–07 and 2009–10, the USGS collected geophysical and flowmeter logs from drilled test holes to characterize the fractured-bedrock aquifer in the study area. The geophysical and flowmeter logs were analyzed along with drilling 

logs to define the stratigraphic units and flow zones intersected 

by the test wells. The location of the contributing flow zones 

within each wellbore was subsequently used by GSC to design 

discrete-zone monitoring installations for the test wells. The 

geophysical and flowmeter logging were critical to the RI/FS 

investigation in that they greatly aided the RI/FS contractor in 

their design of discrete-zone monitoring installations in both 

test and residential wells in a timely manner.

In 2008, construction of a pipeline to import publicly 

supplied water to the 120 affected homes began. Geophysical 

logs for 23 of the most contaminated residential wells were 

collected by the USGS during 2009–10 to identify fractures 

that were potential pathways for the movement of contaminated groundwater; these wells were subsequently converted 

to multi-zone monitoring wells by GSC because of the results 

of the geophysical logging and downhole volatile organic 

compound (VOC) sampling. Geophysical logs and flow logs 

from the 23 contaminated residential wells were collected 

under pumping and ambient conditions in order to identify 

the principal flow zones. Once the principal flow zones in 

each well were identified, a downhole, wireline, point water 

sampler was used to obtain water samples at each flow zone, 

under both ambient and pumped conditions. The location of 

the contributing flow zones in each well was subsequently 

used by GSC to design discrete-zone monitoring installations 

in selected residential wells.

Purpose and Scope

This report describes the geophysical logging methods 

used to evaluate and characterize 20 bedrock test holes and 

23 residential wells at the Shenandoah Road National Superfund Site and presents the results of the analysis of the geophysical logs and aquifer tests used to characterize the lithology, fabric, fractures, and flow zones penetrated by each well. 

The report also gives estimates of the overall transmissivity of 

each borehole and presents a relation between borehole transmissivity and specific capacity.

Bedrock Geology

The Shenandoah Road National Superfund Site is 

situated atop Shenandoah Mountain, which is a northeast 

trending mountain that is part of the northern border of the 

Hudson Highlands (fig. 1). Shenandoah Mountain is primarily composed of Precambrian gneiss, whereas the surrounding 

lowlands are underlain by carbonate units of the Wappinger 

Group. These rock units are described in more detail below.

Precambrian Gneiss

The greater part of Shenandoah Mountain is composed 

of Precambrian (Proterozoic-age) garnet-bearing gneiss with 

interlayered quartzite of the Hudson Highlands Complex 

gneisses. Mineralogically, the gneiss contains biotite, garnet, 

sillimanite, minor marble, amphibolite, and rusty para-gneiss. 

Helenek (1972) refers to this rock as “biotite migmatic gneiss, 

garnetiferous facies.” Shenandoah Mountain is one of a series 

of enechelon, fault-bounded structural blocks that compose the 

northern edge of the Hudson Highlands in southern Dutchess 

County. These blocks are composed of gneissic rock that has 

resulted from intense plastic deformation and at least one 

episode of brittle deformation (tectonics). Evidence of brittle 

deformation is widespread in the study area. Helenek (1972) 

reported that minor faults and microfractures in the gneiss 

are abundant; most faults appear to be strike-slip faults with 

left-lateral strike-slips predominating. Three directions of 

strike-slip movement are prominent—N.10°W., N.52°W., 

and N.27°E.—with most fault planes inclined at a high angle 

(about 60°) to the south (Helenek, 1972). Two prominent 

joint sets are also found in the gneiss, a dominant set trending 

N.39°W. with a dip of 80°S and a second set trending N.75°W. 

and dipping 85° N.

Wappinger Group

Carbonate units, primarily the Wappinger Group, that 

overlie and abut the gneisses of the Hudson Highlands 

Complex are Paleozoic (Cambrian and early Ordovician) 

rocks (Fisher, 1977). The Wappinger Group, as described by 
Structural Geology 5

Fisher (1977) consists of a series of Cambrian and Ordovician 

carbonate units, beginning with the Poughquag Quartzite (of 

Dana, 1872) at the base and ending with the Copake Limestone (of Dana, 1872) at the top. Other stratigraphers, such as 

Dana (1879), include the overlying Balmville Limestone (of 

Holzwasser, 1926); however, more recent correlation charts 

(Fisher, 1977) omit the Balmville Limestone. The Wappinger 

Group, as mapped and defined by Fisher (1977) consists of the 

following units (from oldest to youngest): Poughquag Quartzite (of Dana, 1872), Stissing Dolomite (Ratcliffe and Burton, 

1990), Pine Plains Formation (of Knopf, 1946), Briarcliff 

Dolomite (Ratcliffe and Burton, 1990), Halcyon Lake Formation (Ratcliffe and Burton, 1990), Rochdale Formation (of 

Dwight, 1887), and the Copake Limestone (of Dana, 1879). 

Helenek (1972) describes only the three lowermost carbonate 

units of the Wappinger Group, which he calls units A, B, and 

C. Unit A is roughly equivalent to the Stissing Dolomite, unit 

B is the equivalent of the Pine Plains Formation, and unit C 

is equivalent to the Briarcliff Dolomite. Within the immediate 

Shenandoah Road Superfund Site study area, only the Stissing 

Dolomite, Pine Plains Formation, and Briarcliff Dolomite are 

thought to be present (Offield, 1962; Fisher, 1968; Helenek, 

1972). These units are briefly described in ascending stratigraphic order below.

Poughquag Quartzite

The Poughquag Quartzite is the lowest unit of the Wappinger Group and is separated from the underlying Precambrian gneisses by a folded angular unconformity. Helenek 

(1972) reported that the Poughquag Quartzite is always 

separated from the underlying gneisses by a 3-ft-thick zone 

of massive arkose metaconglomerate. The metaconglomerate 

is a drab olive-gray to dull yellowish-white, poorly sorted, 

massive to slightly gneissoid rock with a variable grain size. 

Helenek (1972) regarded this metaconglomerate as a transitional horizon between the Poughquag Quartzite and the 

underlying gneisses because the pronounced foliation in the 

gneisses gradually disappears in the basal part of the metaconglomerate. The upper part of the metaconglomerate exhibits 

faint bedding parallel to that of the quartzite. The contact 

between the metaconglomerate and the Poughquag Quartzite 

is sharp, and the basal part of the quartzite consists of interlensed quartzite, subarkose, and quartz conglomerate. The 

quartzitic facies is a massive to well-layered, white, buff, rusty 

brown or gray, well-sorted, fine-grained quartz sandstone. The 

conglomeratic facies contains pebbles of angular to subangular 

quartz and microcline set in a quartzite matrix. The Poughquag 

Quartzite is the equivalent of the Cheshire Quartzite of western Massachusetts and is a compact, competent rock so tough 

to drill that it is deliberately avoided by water-well drillers 

(Simmons and others, 1961).

Stissing Dolomite

The Stissing Dolomite is a massive, white to light-gray, 

fine grained, foliated dolostone that weathers to a pale gray 

where exposed in outcrops. The contact between the Stissing 

Dolomite and the underlying Poughquag Quartzite is gradational, with interlayering of quartzite and quartz-bearing 

dolostones over a stratigraphic distance of up to 50 ft (Fisher 

and McLelland, 1975). Gray or green shale interbeds are present in some intervals, as are localized chert, quartzite layers, 

and quartz-filled fractures. In some sections, dark, laminated 

dolomite layers are observed. The total thickness of the Stissing Dolomite is estimated to be about 500 ft (Knopf, 1946), 

which matches the thickness estimate of Fisher and Warthin 

(1976) in western Dutchess County. The lower and middle 

sections of the Stissing Dolomite have been interpreted to be 

of Lower Cambrian age, whereas the uppermost section may 

be Middle Cambrian in age.

Pine Plains Formation

The Pine Plains Formation of Middle to Upper Cambrian 

age is the most highly variable unit within the Wappinger 

group; it has the varying colors and textures of dolostone that 

alternate with sandstone or quartzitic dolostone beds. Bedding 

tends to be graded and cyclical with variable bedding thicknesses and with the dolostone commonly alternating with dark 

gray shale interbeds. Oolites, ripple marks, cross-laminations, 

and desiccation cracks are common. The thickness of the 

Pine Plains Formation has been estimated to be 90 to 1,300 ft 

(Helenek and Mose, 1976; Knopf, 1946); however, in western Dutchess County its thickness has been estimated to be 

1,150 ft (Fisher and Warthin, 1976).

Briarcliff Dolomite

The Briarcliff Dolomite of Upper Cambrian age consists 

of massively bedded, light-to-dark gray, arenaceous, quartzitic 

dolostones that weather to colors ranging from tan to orangebrown to brown. Thickness estimates for the Briarcliff Dolomite range from 215 to 1,000 ft (Helenek and Mose, 1976; 

Knopf, 1946).

Structural Geology

The gneissic rocks of the Precambrian Hudson Highlands 

Complex in southern Dutchess County have been deformed 

into a series of open to closed, asymmetrical and overturned 

folds that gently plunge to the northeast. All of these are flexural slip folds with movement occurring along bedding and 

foliation planes (Helenek, 1972). The limestone and dolomite 

units of the Wappinger Group have been metamorphosed to 

various degrees; the intensity of the metamorphism increases 

from northwest to southeast across Dutchess County. In the 
6 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York

southeastern part of the county, the marble units there have 

been so severely deformed by plastic flow that they appear to 

be wrapped around more competent rock units (Simmons and 

others, 1961). Shenandoah Mountain itself is bounded by a 

normal fault to the east in which the adjacent valley (underlain 

by the Wappinger Group) represents the downthrown side. 

Another normal fault similarly defines the east side of Round 

Mountain (East Hook), just west of Shenandoah Mountain. 

Fisher (1968) mapped a third normal fault between those 

two, running northeast through the Wappinger Group, with 

the downthrown side to the west. Very few actual measurements of strike and dip of bedding or jointing have been 

made by field investigators on Shenandoah Mountain. Offield 

(1962) made three strike and dip measurements (presumably of jointing) in the Precambrian gneisses of Shenandoah 

Mountain along the Dutchess–Putnam county line. His values 

were (approximately) N. 38° E., with a dip of 70° SE; N. 

35° E., with a dip of 20° NW; and N. 27° E., with a dip of 

70° SE. Offield (1962) also made a measurement within the 

downthrown block of amphibolite, just east of the eastern 

Shenandoah Mountain fault, which was (approximately) 

N.16° E.,with a dip of 52° SE. These limited data appear to 

show the predominant high-angle joint set on Shenandoah 

Mountain to trend about N. 30° to 35° E. and dip steeply (70°) 

to the southeast. This pattern is repeated to the west of the 

study area, near Sharp Reservation, where many strike and dip 

measurements made by Helenek (1972) in the Precambrian 

gneisses reveal a similar trend.

Little data are available on the strike and plunge of folding on Shenandoah Mountain. Helenek (1972) noted that in 

the vicinity of Sharp Reservation, to the west, the axial planes 

of folds in the Precambrian gneisses trend about N. 46° E. and 

dip 80° N., and the fold axes strike N. 45° E. and plunge 12°

N. However, regional tectonics has caused the axial planes 

of folds in the overlying Wappinger Group to be rotated to 

the north. Helenek (1972) noted that, southeast of Wiccopee, 

folds in the dolostones within the Wappinger Group have axial 

planes oriented about N.7° E. with a dip of 58° S. and with the 

fold axes rotated and trending N. 25° E. and plunging 14° N. 

Slaty cleavage and foliation in the Wappinger Group is parallel or subparallel to the axial planes of folds. Helenek (1972) 

also noted that faults in the Paleozoic gneisses are either 

high-angle normal faults or low-angle thrust faults; some 

thrust faults are at an almost horizontal plane. Brecciated fault 

planes were usually cemented with coarse-grained quartz and 

carbonate minerals.

Surficial Geology

Deglaciation in the vicinity of Shenandoah Mountain left 

a variety of surficial deposits and landforms, including end 

moraines, ice-contact deposits of sand and gravel, valley train 

outwash, fine-grained lacustrine deposits, and till. The surfical geology in the area was mapped on a materials basis by 

Gerber (1982) and on a morphostratigraphic basis by Connally 

(1980). Reynolds and Calef (2010) summarize the surficial 

geology of the Sprout and Fishkill Creek drainages just to the 

north of Shenandoah Mountain.

Connally and Sirkin (1986) detail the chronology of 

the deglaciation of the mid-Hudson valley in Dutchess and 

Columbia Counties and define a series of ice-marginal positions along with the associated morainal landforms. In general, 

the valleys of Sprout Creek, Wiccopee Creek, and Whortlekill Creek are all floored with valley train outwash, which is 

underlain by thick deposits of lacustrine silt and clay (Reynolds and Calef, 2010). The Precambrian bedrock uplands 

(Shenandoah, Hosner, and Honess Mountains) are covered 

with a thin (less than 6 ft thick) veneer of till; however, the 

steepest slopes are generally exposed bedrock. In the vicinity 

of East Fishkill, exposed outcrops of Wappinger Group rocks 

are covered with a thin veneer of till, and in the main valleys 

near Hopewell Junction, north-south trending drumlinoid 

hills punctuate the pitted outwash of the Sprout Creek valley 

(Reynolds and Calef, 2010).

Shenandoah Moraine

The most notable glacial landform that may affect the 

hydrogeology of the Shenandoah Road Superfund site is the 

Shenandoah Moraine (Connally and Sirkin, 1986; Reynolds 

and Calef, 2010, sheet 2), a discontinuous string of ice-contact 

deposits that mark an ice-marginal position that stretches for 

about 3 miles from just south of Beacon, N.Y., along the northern edge of the gneisses of the Hudson Highlands Complex 

(Honess, Shenandoah, and Hosner Mountains) to the village of 

Poughquag near West Mountain. Connally and Sirkin (1986) 

tentatively correlated the Shenandoah Moraine with the Pellets 

Island Moraine in the Wallkill River valley to the west and 

estimated the age to be about 17,500 years before present.

The Shenandoah Moraine, although it may mark an icemarginal position, appears to be mostly composed of ice-contact, stratified drift (a kame moraine) instead of till. Gordon 

(1911) recognized the 180-ft high landforms that “guard the 

approach to Shenandoah hollow” as kames, and Connally and 

Sirkin (1986) state that the moraine is mostly composed of 

fragmentary landforms of stratified drift. Gerber (1982) simply 

labels it as sand and gravel, and Connally (1980) maps it as 

kame sand and gravel. The part of the moraine that blocks 

the entrance to the narrow valley between Shenandoah and 

Hosner Mountains appears from the topography to be composed, either wholly or in part, of either eskers or ice-channel 

fillings. The narrow ridge that begins at the nose of Shenandoah Mountain and extends east-west across the narrow valley 

appears to be an esker, and other parts of this segment of the 

moraine appear to display ice-contact slopes. Another segment of this kame moraine to the northeast across the Taconic 

State Parkway contains a gravel pit and shows evidence of 

being an ice-channel filling. Two wells, a dug well (Du-961) 

and a driven well (Du-444) (Reynolds and Calef, 2010, sheet 
Data Collection 7

1) tap these deposits to depths of about 25 ft. At least one of 

these wells (Du-961) has had a sufficient yield to supply water 

to 60 head of livestock (Simmons and others, 1961). These 

ice-contact deposits of sand and gravel are deposited atop 

Wappinger Group carbonates and may represent areas where 

recharge to the underlying bedrock aquifer is facilitated.

Outwash Sand and Gravel

Outwash sand and gravel compose the floors of the 

valleys of Sprout and Wiccopee Creeks, extending southward from Fishkill Plains to the IBM facility at East Fishkill 

(Reynolds and Calef, 2010, sheet 2). Much of this outwash 

is what is known as pitted outwash, which is outwash punctuated by numerous small closed depressions that indicate 

deposition around small blocks of disintegrating glacial ice. 

Beneath the outwash are deposits of lacustrine silt and clay 

deposited into Glacial Lake Fishkill (Connally and Sirkin, 

1986), which occupied the Sprout and Whortlekill Creek 

valleys as the ice receded northward from the Shenandoah 

Moraine to an ice-margin near Poughkeepsie, N.Y. Logs of 

wells in the Wiccopee Creek valley, about 3 miles northwest 

of the Shenandoah Road National Superfund Site, show that 

the surficial outwash is thin in most areas and absent in others 

but that a lower confined sand and gravel aquifer is present 

in some places. For example, well Du-429 at Wiccopee was 

drilled to 116 ft, penetrating 63 ft of gray silt before passing 

through 30 ft of fine sand and gravel and entering brown clay. 

The driller noted that the 30 ft of sand and gravel was the main 

water-bearing zone. Heads in this confined sand and gravel 

aquifer are, at least seasonally, above land surface. Nearby 

well Du-476 at Wiccopee is 85 ft deep, flowed at 3 gallons per 

minute (gals/min) when originally drilled, and appears to be 

completed in the same confined aquifer as well Du-429. Well 

Du-465 is closer to the Shenandoah Road site than the other 

two wells, is 230 ft deep, yields 18 gals/min, and is completed 

in ice-contact sand and gravel that abuts the northwest side of 

Shenandoah Mountain.

Description of Wells

Twenty test wells and 23 residential wells were logged 

by downhole geophysical methods at the Shenandoah Road 

National Superfund Site. The locations of the logged wells are 

presented in figure 1. Well location and construction information and the ambient water level recorded at the time of 

geophysical logging are presented in table 1.

Test Wells

Of the 20 test wells (Du-3225 to Du-3244) constructed 

under the direction of GSC, 19 are 6-inch (in.) diameter openhole wells, and one, well Du-3227, is a 4-in. diameter core 

hole. All wells were drilled by a commercial well driller using 

an air-hammer drill rig. Most of the test wells were designed to 

have depths of 500 ft; however, some were completed at lesser 

depths. The casings were installed into the top of bedrock in 

all of the test wells, except Du-3233, Du-3236, Du-3237, and 

Du-3240, which are near the contamination source and have 

casings set to targeted depth intervals, and wells Du-3232 and 

Du-3244, which are cased to 155 ft and 269 ft, respectively. 

Each test well was completed by GSC with a Flute liner that 

has multiple water-quality and hydraulic-head measurement 

ports installed at the depth of flow zones identified through the 

geophysical log analysis.

Residential Wells

The 23 residential wells were constructed as 6-in-diameter open-hole wells with casings that terminate just below the 

top of bedrock, except for Du-3257, which was finished as a 

shallow sand and gravel well. The residential wells selected 

for logging were known to produce water with PCE concentrations greater than drinking-water standards and were no 

longer in use following the installation of the public-watersupply system. Prior to USGS logging, GSC arranged to have 

the submersible pumps pulled and subsequently inspected 

each well with a downhole camera to insure that there were 

no obstacles in the wellbore. GSC personnel also interviewed 

each homeowner, explained the nature of the geophysical 

logging, and obtained signed well-access agreements before 

the USGS could proceed with the logging. The wells were 

logged in three phases; 7 wells were logged during August and 

September 2009, 13 wells during October 2009, and 3 wells 

during January 2010. Selected residential wells were completed by GSC with 2-inch (in.) diameter casings and screens 

to isolate flow zones identified through the geophysical-log 

analysis for subsequent water-quality sampling and hydraulichead measurement.

Data Collection 

Geophysical logs and associated data were collected from 

the 20 test wells and 23 residential wells at the Shenandoah 

Road National Superfund Site. The types of logs collected 

from each well are shown in table 2. Drilling logs for the test 

wells were collected by GSC and provided to the USGS.

Drilling Logs for Test Wells

Drilling logs are records of observations from the drilling 

operation and include lithology of drill-cuttings, blown-yield, 

and fracture logs. The three types of drilling logs collected at 

the site are described below.

Drill-cuttings logs are records of the lithology of unconsolidated sediments and bedrock types penetrated by the well 
8 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York Table 1. Location, construction, and water-level information for selected wells at the Shenandoah Road National Superfund Site, Dutchess County, N.Y. [USGS, U.S. Geological Survey] County Well No.1 Site well number Well type2 Latitude3 Longitude3 Land-surface Elevation4 Well Depth5 Well Diameter6 Casing Depth7 Water Date8 Level Depth9 Lithology10 3225 SRMW-1RB

T 413138.4 734738.2 482.57 400 6 28.5 1/10/2006 5.23 Gneiss

3226 SRMW-2R

T 413155.8 734704.5 358.08 500 6 44.8 1/12/2006 44.80 Dolomite/gneiss

3227 SRMW-18core

T 413135.8 734734.9 505* 127 4 29.1 1/19/2006 6.69 Gneiss

3228 SRMW-19

T 413133.2 734712.1 322.69 500 6 86.0 11/15/2006 1.26 Dolomite/quartzite

3229 SRMW-20

T 413117.1 734726.8 341.96 320 6 36.4 11/17/2006 **-11.00 Dolomite/quartzite/gneiss

3230 SRMW-15

T 413145.6 734724.2 425.58 500 6 66.0 11/20/2006 56.99 Gneiss

3231 SRMW-14

T 413151.5 734734.2 348.97 141 6 90.0 11/21/2006 29.05 Dolomite

3232 SRMW14A

T 413151.3 734734.2 348.18 500 6 145.0 11/28/2006 27.40 Dolomite

3233 SRMW-18C

T 413135.4 734734.3 504.46 247 6 155.0 12/8/2006 32.10 Gneiss

3234 SRMW-17

T 413139.5 734723.6 384.01 500 6 18.0 3/11/2007 18.00 Gneiss

3235 SRMW-12

T 413203.1 734729.0 297.43 500 6 118.0 12/14/2006 -0.02 Dolomite

3236 SRMW-18B

T 413136.1 734734.8 504.28 160 6 101.0 2/21/2007 17.75 Gneiss

3237 SRMW-18D

T 413136.0 734735.5 504.62 320 6 248.0 12/20/2006 76.00 Gneiss

3238 SRMW-18E

T 413135.5 734735.5 504.73 295 9 40.5 1/23/2007 19.92 Gneiss

3239 SRMW-18A

T 413135.7 734735.3 504.56 80 6 44.0 2/21/2007 30.49 Gneiss

3240 SRMW-18F

T 413136.0 734735.2 505.03 501 6 321.0 3/15/2007 35.70 Gneiss

3241 SRMW-11

T 413206.5 734714.7 306.37 500 6 54.0 3/14/2007 10.82 Dolomite/quartzite/gneiss

3242 SRMW-16

T 413144.8 734725.3 417.75 499 6 30.5 3/15/2007 28.70 Gneiss

3243 SRMW-12R

T 413203.1 734729.0 297.23 502 6 269.0 6/26/2007 flowing Dolomite

3244 SRMW-4

T 413226.0 734735.6 277.99 502 6 45.0 6/27/2007 2.23 Dolomite

3245 SHN-472

R 413149.5 734734.9 340* 92 6 88.8 8/25/2009 19.90 Dolomite

3246 BRB-005

R 413136.9 734727.8 447* 276 6 20.0 8/27/2009 24.68 Gneiss

3247 BRB-003

R 413134.4 734727.4 445* 275 6 18.5 8/28/2009 0.90 Gneiss

3248 SEY-004

R 413138.7 734718.8 360* 159 6 10.8 8/31/2009 10.87 Gneiss

3249 SHN-589

R 413128.5 734723.9 360* 203 6 19.5 9/1/2009 3.16 Gneiss

3250 SEY-006

R 413137.1 734719.4 365* 220 6 31.0 9/2/2009 10.29 Gneiss

3251 BRB-014

R 413139.3 734721.1 368* 199 6 31.0 9/3/2009 20.19 Gneiss

3252 SEY-005

R 413137.4 734715.7 345* 322 6 51.5 10/29/2009 3.62 Dolomite/gneiss

3253 STN-051

R 413129.6 734734.7 535* 213 6 19.5 10/30/2009 98.81 Gneiss

3254 GRF-007

R 413143.4 734741.3 340* 91 6 22.5 10/13/2009 33.37 Dolomite
Data Collection 

9

Table 1. Location, construction, and water-level information for selected wells at the Shenandoah Road National Superfund Site, Dutchess County, N.Y. —Continued[USGS, U.S. Geological Survey]

County Site Well Land-surface Well Well Casing Water Level Well Latitude3 Longitude3 Lithology10 well number type2 Elevation4 Depth5 Diameter6 Depth7 Date8 Depth9 No.1

3255 EHC-002 R 413144.7 734730.6 390* 227 6 27.0 10/14/2009 27.21 Gneiss

3256 TWN-134 R 413209.6 734720.9 285* 344 6 49.5 10/15/2009 flowing Dolomite/quartzite

3257 CHN-472 R 413149.6 734734.4 325* 42 6 41.8 10/19/2009 10.46 Sand & gravel/dolomite

3258 SHN-478 R 413149.6 734734.4 343* 105 6 62.5 10/19/2009 34.84 Dolomite3259 BRB-006 R 413136.4 734723.2 375* 235 6 39.5 10/20/2009 29.09 Gneiss3260 SHN-603 R 413124.0 734724.6 348* 248 6 24.5 10/21/2009 2.80 Gneiss3261 SHN-499 R 413145.5 734728.6 405* 148 6 23.8 10/22/2009 32.96 Gneiss3262 BRB-011 R 413138.5 734726.6 435* 214 6 31.5 10/26/2009 4.66 Gneiss3263 BRB-009 R 413138.7 734727.7 450* 308 6 18.5 10/27/2009 10.80 Gneiss3264 BRB-007 R 413136.1 734726.5 425* 235 6 28.5 10/28/2009 3.62 Gneiss3265 JCK-117 R 413158.6 734729.4 320* 522 6 60.0 1/20/2010 3.29 Dolomite/gneiss3266 SEY-007 R 413136.0 734715.9 345* 116 6 42.5 1/18/2010 5.75 Dolomite/quartzite/gneiss

3267 SHN-591 R 413126.9 734725.8 355* 155 6 33.0 1/21/2010 1.30 Gneiss

1 County sequential number assigned by USGS, prefix Du for Dutchess County not shown.2 T denotes test well, R denotes residential well.3 Degrees, minutes, seconds, and tenths of seconds; North American Datum 1983.4 Land-surface elevation, surveyed in feet above North American Vertical Datum of 1988; elevations to the nearest 100th foot.5 Depth of well, in feet below land surface; depth to the nearest foot.6 Diameter of well in inches.7 Depth of casing, in feet below land surface.8 Date of water-level measurement.9 Depth to water level, in feet below land surface.10 Slash (/) separates major rock types stratigraphically downward.* Well elevation estmated to nearest foot from USGS 1:24,000 topographic map.** Based on pressure measured at adjacent well open to same interval.
10 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York Table 2. Types of geophysical logs collected from selected wells at the Shenandoah Road National Superfund Site, Dutchess County, N.Y. [Well locations shown in figure 1. USGS, U.S. Geological Survey; no., number; dash (-), not available; X indicates log was collected. Drilling logs supplied by Groundwater Sciences Corporation, 2001-10. The prefix “Du” has been omitted from the county well numbers] Type of logs County well number Well site no. Drilling logs1 Gamma2 Cond3 Mag susc4 OTV MN5 ATV MN6 Caliper7 Flow8 Fl cond9 Temp10 Cl11 Redox12 O213 Dev14 3225 SRMW-1RB

X

X

X

X

X

X

X

X

X

X - - - X

3226 SRMW-2R

X

X

X

X

X

X

X

X

X

X - - - X

3227 SRMW-18core

X

X

X

X

X

X

X

X

X

X - - - X

3228 SRMW-19

X

X

X - X

X

X

X

X

X

X

X

X

X

3229 SRMW-20 

X

X

X - - X

X

X

X

X - - - X

3230 SRMW-15

X

X

X

X

X

X

X

X

X

X

X

X

X

X

3231 SRMW-14

X

X

X - X

X

X

X

X

X

X

X

X

X

3232 SRMW-14A

X

X

X - X

X

X

X

X

X

X

X

X

X

3233 SRMW-18C

X

X

X - X

X

X

X

X

X

X

X

X

X

3234 SRMW-17

X

X

X

X

X

X

X

X

X

X

X

X

X

X

3235 SRMW-12

X

X

X

X

X

X

X

X

X

X

X

X

X

X

3236 SRMW-18B

X

X

X

X

X

X

X

X

X

X - - - X

3237 SRMW-18D

X

X

X

X

X

X

X

X

X

X

X

X

X

X

3238 SRMW-18E

X

X

X

X

X

X

X

X

X

X

X

X

X

X

3239 SRMW-18A

X

X

X

X

X

X

X - X

X - - - X

3240 SRMW-18F

X

X

X

X

X

X

X

X

X

X - - - X

3241 SRMW-11

X

X

X

X

X

X

X

X

X

X - - - X

3242 SRMW-16

X

X

X

X

X

X

X

X

X

X - - - X

3243 SRMW-12R

X

X - - X

X

X

X - - - X

3244 SRMW-4

X

X

X - X

X

X

X - - - X

3245 SHN-472 - X - - X

X

X - - - - X

3246 BRB-005 - X - - X

X

X

X

X

X - - - X

3247 BRB-003 - X - - X

X

X

X

X

X - - - X

3248 SEY-004 - X - - X

X

X

X

X

X - - - X

3249 SHN-589 - X - - X

X

X

X

X

X - - - X

3250 SEY-006 - X - - X

X

X

X

X

X - - - X

3251 BRB-014 - X - - X

X

X

X

X

X - - - X

3252 SEY-005 - X - - X

X

X

X - - - X

3253 STN-051 - X - - X

X

X

X

X

X - - - X
Data Collection 11

Table 2. Types of geophysical logs collected from selected wells at the Shenandoah Road National Superfund Site, Dutchess County, N.Y.[Well locations shown in figure 1. USGS, U.S. Geological Survey; no., number; dash (-), not available; X indicates log was collected. Drilling logs supplied by Groundwater Sciences Corporation, 2001-10. The prefix “Du” has been omitted from the county well numbers]

 Type of logs

County

well

number

Well

site no. Drilling logs1 Gamma2 Cond3 Mag susc4 OTV MN5 ATV MN6 Caliper7 Flow8 Fl cond9 Temp10 Cl11 Redox12 O213 Dev14

3254 GRF-007 - X - - X X X X - - - X3255 EHC-002 - X - - X X X X X X - - - X3256 TWN-134 - X - - X X - X X X - - - X3257 CHN-472 - X - - - X - - X - - - X

3258 SHN-478 - X - - - X - X X - - - X

3259 BRB-006 - X - - X X - X X - - - X3260 SHN-603 - X - - X X X X X - - - X

3261 SHN-499 - X - - X X X X X X - - - X

3262 BRB-011 - X - - X X X X X - - - X3263 BRB-009 - X - - X X X X X - - - X

3264 BRB-007 - X - - X X X X X - - - X

3265 JCK-117 - X X X X X X X X X - - - X

3266 SEY-007 - X X X X X X X X X - - - X

3267 SHN-591 - X X - X X X X X X - - - X

1 Drill-cutting description, cumulative blown yield, and fracture depths.2 Gamma.3 Electromagnetic induction conductivity.4 Magnetic susceptibility.5 Optical televiewer.6 Acoustic televiewer.7 Caliper.8 Wellbore flow.9 Fluid conductivity.10 Temperature.11 Fluid chloride.12 Fluid reduction/oxidation potential.13 Fluid dissolved oxygen.14 Wellbore deviation.

—Continued
12 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York

and are based on the GSC geologist’s description of samples 

of drill cuttings collected at selected depth intervals. Continuous-core samples were collected at Du-3227 and described by 

the GSC geologist.

Blown-yield logs are records of the cumulative discharge 

blown from the well during air-hammer drilling. They provide 

an estimate of the cumulative water yield of the wellbore 

while drilling.

Fracture logs are records of fractured zones detected during drilling. Penetration of fractured zones during drilling may 

be indicated by increased drilling rates, sudden drops in drill 

bit position, and loss or gain of drilling fluids.

Geophysical Logs

Geophysical logs were collected by the USGS using a 

truck-mounted drawworks that holds approximately 2,000 ft 

of armored four-conductor cable. Each downhole tool (probe) 

is attached to the cable head and run down the well at the 

prescribed speed for each geophysical tool. Most tools collect 

data on multiple characteristics; for example, the fluid-conductivity probe collects fluid conductivity, temperature, and 

gamma logs simultaneously. Data-collection speeds (rates of 

descent or ascent) range from 20 feet per minute (ft/min) for 

most logging tools to about 5 ft/min for the optical and acoustic logging tools. Data from each tool are continually recorded 

on a laptop computer and are viewed in real time in the field.

Examples of the types of geophysical logs collected 

from both the test holes and the residential wells are presented 

in appendix 1 and include gamma, caliper, borehole-image, 

deviation, fluid-property, electromagnetic-induction, magneticsusceptibility, and flowmeter logs. The caliper logs were 

collected by mechanical and acoustic methods. Boreholeimage logs were collected with an optical televiewer (OTV) 

and an acoustic televiewer (ATV). Borehole-deviation logs 

were collected with three-axis fluxgate magnetometers and 

vertical inclinometers that are incorporated into the ATV and 

OTV probes. Fluid-property logs included fluid-conductivity, 

temperature, dissolved oxygen, chloride, and redox potential 

measurements of the borehole water. Flowmeter logs were collected by heat-pulse or electromagnetic methods. The types of 

geophysical logs collected in each well are listed in table 2.

Applications of geophysical logs in groundwater studies 

are described by Williams and Lane (1998) and Keys (1990). 

The geophysical logs used in this investigation are described 

briefly below.

Gamma logs measure the natural gamma radiation of the 

rock units penetrated by the borehole. Major gamma emitters 

are uranium, thorium, and daughter products of potassium-40. 

Sedimentary rocks with relatively high gamma radiation when 

compared to other lithologic units include shales, mudstones, 

and other argillaceous units. Igneous and metamorphic rocks 

rich in potassium feldspar are also high gamma emitters. The 

gamma tool has a vertical resolution of 1 to 2 ft. Gamma logs 

collected in open holes and through steel casing may be used 

for lithologic identification and stratigraphic correlation.

Electromagnetic-induction conductivity logs measure the 

electrical conductivity of bedrock and water surrounding the 

borehole. In this study, the logs were collected at a frequency 

of 40 kilohertz (kHz). The electromagnetic-induction tool has 

a vertical resolution of about 2 ft and primarily samples volumes to about 18 in. radially from the well. It generally is not 

affected by the electrical properties of the wellbore fluid for 

diameters less than 8 in. Electrical conductivity measurements 

are affected by the argillaceous content and porosity of the 

rocks and by the concentration of dissolved solids in the pore 

fluid. Electromagnetic-induction conductivity logs are most 

effective in formations with high electrical conductivities (low 

resistivities), such as shales and mudstones.

Magnetic-susceptibility (MAG) logs provide a record 

of the variations in magnetic minerals within the surrounding rock. Magnetite is the most common magnetic mineral, 

and local variations in its abundance may indicate lithologic 

contacts.

Mechanical and acoustic caliper logs record the diameter 

of the borehole. Changes in borehole diameter are related to 

drilling and construction procedures and competency of lithologic units, fractures, and solution features. Mechanical-caliper 

logs were collected with a spring-loaded, three-arm averaging 

tool; acoustic-caliper logs were calculated from acoustic travel 

times collected with the ATV tool. Caliper logs were used in 

the delineation of fractures, solution features, and lithology, 

and to confirm well and casing depths and diameters.

ATV logs record a 360-degree magnetically oriented 

acoustic image of the borehole wall (Williams and Johnson, 

2000). ATV logs can be collected in clear or turbid water. The 

ATV provides high-resolution information on the location and 

strike and dip of fractures or bedding within a borehole, such 

that structural features with widths greater than 0.02 ft can 

easily be identified. ATV logs were used to characterize bedding and lithology, fracture aperture and orientation, solution 

features, and borehole-wall roughness.

OTV logs record a 360-degree oriented optical image 

of the wellbore wall. OTV logs can be collected above the 

water level and below the water level where the water is clear. 

Features with widths greater than 0.008 ft can be identified. 

OTV logs were used to characterize bedding and lithology, 

fractures, and solution features (Williams and Johnson, 2000).

Deviation logs measure the inclination and direction 

of the well from vertical. Inclination generally is measured 

within ± 0.5 degree and direction within ± 2 degrees. Deviation direction is given in magnetic north. In test wells that 

penetrate magnetite bearing zones, deviation direction can be 

affected by the secondary magnetic field generated by the ferrous minerals.

Temperature (Temp) logs record the temperature of air 

and water in the wellbore. Temperature gradients that deviate 

from the geothermal gradient may indicate intervals of wellbore flow. Temperature logs were used to delineate the water 

level and possible changes in wellbore flow.
Geophysical Log Analysis 13

Fluid-conductivity (Cond) logs record the electrical conductance of water in the wellbore. Electrical conductance is 

directly related to the concentration of dissolved solids in the 

water. Slope changes in fluid-conductivity logs may indicate 

zones of inflow to, or outflow from, the borehole. Fluidconductivity logs were used to delineate possible changes in 

wellbore flow. 

Fluid dissolved oxygen logs record the amount of dissolved oxygen, in parts per million, of water in the wellbore. 

Slope changes in dissolved oxygen logs may indicate zones 

of inflow to, or outflow from, the wellbore. Dissolved oxygen 

logs were used to delineate possible changes in the wellbore 

flow.

Fluid chloride logs record the amount of chloride, in 

milligrams per liter, of water in the wellbore. Slope changes in 

chloride logs may indicate zones of inflow to, or outflow from, 

the wellbore. Chloride logs were used to delineate possible 

changes in the wellbore flow.

Fluid redox logs record the oxidization or reduction 

potential of the water in millivolts. Slope changes in redox 

logs may indicate zones of inflow to, or outflow from, the 

wellbore. Redox logs were used to delineate possible changes 

in the wellbore flow.

Flow logs record the direction and rate of vertical flow 

in the borehole. Vertical flow occurs in wells that penetrate 

two or more water-producing fracture zones with different 

hydraulic heads (water levels). Flow in the borehole is from 

zones of higher head to zones of lower head. The heat-pulse 

flow meter (Hess, 1982) measures the travel time of a thermal 

pulse between a set of upper and lower heat sensors (thermistors). The flowmeter was used with flexible rubber diverters 

fitted to the nominal borehole diameter and has a measurement 

range of 0.01 to1.5 gallons per minute (gal/min) in a stationary 

mode. Flow logs and fluid-property logs were collected (when 

possible) under (1) steady-ambient (amb) conditions and (2) 

steady-pumping (pmp) or transient-recovery (rec) conditions to provide a contrast of flow-rate gain or loss at discrete 

fracture zones with the boreholes (Paillet, 2000; 2001). To 

measure higher borehole flows, an electromagnetic flowmeter 

was used. The electromagnetic flowmeter (Young and Peterson, 1995) measures fluid velocity, based on Faraday’s Law, 

which states that the flow of an electrically conductive fluid 

through an induced magnetic field generates a voltage gradient 

that is proportional to its velocity. The electromagnetic flowmeter, which was used in stationary and trolling modes with 

a flexible rubber diverter fitted to the borehole diameter, has a 

measurement range of 0.05 to15 gal/min.

Single-Well Aquifer Tests

To estimate the total wellbore transmissivity of each 

well, short-term, single-well aquifer tests were conducted in 

conjunction with pumped flow logging operations. A small 

submersible pump was set in the well near the top of the water 

column and pumped at a low flow rate, generally about 1 gal/

min. In most wells, drawdown in the well was measured continuously with a pressure transducer verified by regular check 

measurements with a water-level tape. After quasi-steady-state 

drawdown was achieved, downhole flowmeter measurements 

were made at multiple depths within the well. The transient 

drawdown data were plotted against time, and the CooperJacob method (Cooper and Jacob, 1946) was used to estimate 

transmissivity for the open part of the wellbore. Assumptions 

of the method include that the aquifer is confined and has infinite areal extent, the aquifer is homogenous and isotropic, flow 

is horizontal to the well, and water is released from storage 

instantaneously. For the purposes of estimating transmissivity in these wells and comparisons with other estimates, these 

assumptions were considered appropriate.

Geophysical Log Analysis 

The geophysical logs and associated data were analyzed to characterize the lithology, structural features (fabric 

and fractures), and flow zones penetrated by the wells. The 

geophysical logs along with the results of short-term, singlewell aquifer tests were used to estimate the transmissivity of 

individual flow zones and the overall transmissivity of the 

wellbore.

Lithology

The suite of geophysical logs, primarily the optical 

televiewer and gamma logs, were used in conjunction with 

the drill-cuttings logs to identify the different rock types 

that were penetrated by the wells. These rock types were 

then correlated with mapped rock units in the study area as 

defined by Fisher and others (1970). Drill-cutting logs were 

not available for the 23 residential wells that were logged, so 

identification of the bedrock lithology was based on the suite 

of geophysical logs collected in each well and their relation to the lithology established in the test wells. Tentative 

identification of rock types in each well were made with the 

aid of the OTV, ATV, electromagnetic-induction, magneticsusceptibility, and gamma logs; identification was confirmed 

by comparison to the extent of mapped bedrock units in the 

study area, as defined by Fisher and others (1970), and field 

mapping conducted by Offield (1962), Fisher (1968), and 

Helenek (1972). There are three types of rock that the test 

wells penetrate—gneisses of the Hudson Highlands Complex 

that compose the Shenandoah Mountain ridge, and dolostones 

and quartzites of the Wappinger Group that underlie the valley 

(table 1). The test wells that penetrate the Hudson Highland 

Complex gneisses are Du-3225, Du-3227, Du-3230, Du-3233, 

Du-3234, Du-3236, Du-3237, Du-3238, Du-3239, Du-3240, 

and Du-3242. The wells that penetrate the Wappinger Group 

dolostones and quartzite are Du-3226, Du-3228, Du-3229, 

Du-3231, Du-3232, and Du-3235. Wells Du-3226, Du-3229, 

and Du-3241 penetrate the Wappinger Group dolostones and 
14 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York

quartzite and continue into the Hudson Highland Complex 

gneisses.

The gamma logs in the Hudson Highland Complex 

gneisses average 250 to 300 counts per second, although there 

are large variations with values ranging from less than 70 to 

more than 800 counts per second. The gamma values vary 

with pegmatite content within the gneiss; the more pegmatite 

present, the higher the gamma count as a result of the larger 

percentage of potassium feldspar in the pegmatite. The quartzite and dolostone gamma values are generally lower, averaging 100 to 150 counts per second but may range from 10 to 

280 counts per second, depending on the shale content. The 

electromagnetic-induction logs average 10 to 20 millisiemens 

per meter (mS/m) in all three rock units with variations as low 

as 1 and as high as 50 mS/m.

In the gneiss, higher values of electromagnetic induction 

generally correspond with zones of higher magnetic susceptibility. The dolostone variations in the electromagnetic-induction log correspond with the gamma log, which shows higher 

values with greater shale content. The magnetic-susceptibility 

logs show variations for gneiss that coincide with zones identified by drill cuttings and core having magnetic and pyritic 

mineralogy, and other zones not seen in the drill cuttings or 

core.

The lithology was visually identified by the optical image 

in the open wellbore. The optical logs in the gneiss show light 

and dark mineral banding. The acoustic image in the non-fractured gneiss shows little change in the hardness or the wave 

absorption properties of the bands. The optical logs in the 

quartzite show no color banding and are generally lighter in 

color than the gneiss and the dolostone. The acoustic image in 

the non-fractured quartzite, like the gneiss, shows little variation. The optical logs in the dolostone show alternating massive (tens of feet thick) and thinly bedded zones with the color 

varying from white to very dark. The acoustic image shows 

changes in the thinly bedded zones within the dolostone, indicating a difference in the hardness or wave absorption between 

the light and dark bedding zones.

Structural Features

Structural features, including foliation, bedding, and fractures, were identified in each logged well through the analysis 

of the suite of geophysical logs collected in each well. OTV 

and ATV logs were used to identify the fabric (foliation and 

bedding) and fractures.

Bedrock Fabric

 The fabric in the wellbore was determined by using the 

OTV and ATV logs to identify the orientations of foliations in 

the gneiss, bedding planes in the dolostone, and lithologic and 

stratigraphic contacts. The bedrock fabric orientation within 

the gneiss reflects the regional northeast-southwest structural 

trend, as well as localized folding. The fabric dip angles 

vary from near horizontal to over 80 degrees. The distribution and orientation of fabric features (foliation and bedding) 

are presented as tadpole plots within the suite of geophysical 

logs for each of three selected wells (appendix 1, figs. 1–1 

through 1–3).

Fractures

The fractures penetrated by the wellbore were characterized by using the optical, acoustic, and caliper logs, along 

with the location of fractures noted in the test wells at time of 

drilling. The fracture log is presented as a tadpole plot of the 

fractures oriented to magnetic north. The fracture azimuth and 

dip amplitude were determined using the OTV and ATV logs. 

Large variations in the fracture azimuth were seen in the fractures. The fracture dip amplitudes vary from near horizontal to 

greater than 85 degrees. Many fractures were oriented along 

or orthogonal to foliation and bedding. Fracture depths were 

confirmed using the caliper log. The distribution and orientation of fractures are presented as tadpole plots within the suite 

of geophysical logs for each well (appendix 1).

Flow Zones

The flow zones penetrated by the wells were characterized by the integrated analysis of the image, caliper, fluidproperty, and flow logs, drilling logs, and single-well aquifer 

test data. The total wellbore transmissivity of the wells was 

estimated through analysis of the single-well aquifer test 

data using the Cooper-Jacob method or through an empirical 

relation between transmissivity and specific capacity developed during this study. The transmissivity and hydraulic head 

of the individual fracture zones penetrated by the wells was 

estimated by analysis of the total wellbore transmissivity and 

the flow logs under ambient and quasi-steady-state pumping 

conditions using the Thiem equation.

Distribution of Flow Zones and Wellbore Flow

The distribution of fracture-flow zones (transmissive fracture zones) and wellbore flow in the test wells and residential 

wells was determined by the integrated analysis of the caliper, 

OTV, ATV, fluid-resistivity, temperature, and flow logs. The 

caliper, OTV, and ATV logs were used to locate points within 

the wellbore where the borehole wall appeared to be competent. These points enabled precise positioning of the flowmeter 

and helped to ensure that the flow diverter would fit snugly 

against the borehole wall, thus diverting the maximum amount 

of borehole flow channeled through the flowmeter measurement chamber. Changes in the fluid resistivity, temperature, 

and flow logs collected under ambient and either pumping or 

recovery conditions were then analyzed along with the fracture 

data from the image and caliper logs to identify water-bearing 

fractures penetrated by the wellbore. One or more fractures 

within each zone typically were identified as transmissive 
Geophysical Log Analysis 15

fractures that contributed to the measured ambient and 

pumped flows. Transmissive fractures are shown in blue on the 

tadpole plots within the suite of geophysical logs in appendix 

1 (figs. 1–1 through 1–3).

Many flow zones were associated with subhorizontal to 

shallow-dipping fractured zones or high-angle dipping fractures. Most of the water-bearing fractures were at depths of 

less than 300 ft, although some water-bearing fractures were 

identified as deep as 500 ft (see fig. 5). The locations of the 

water-bearing fractures in the drilled monitoring wells enabled 

GSC to subsequently design a multi-port well liner (Flute 

system) for each well to monitor heads at individual fracture 

zones and to allow for discrete-zone sampling of VOCs. Moreover, identifying the transmissive fracture zones in the 23 residential wells, now abandoned, enabled the utilization of these 

wells as additional monitoring wells. Results of the analysis 

of geophysical logs were used to guide well reconstruction in 

order to isolate individual or sets of fracture zones.

Estimates of Total Wellbore Transmissivity

The total wellbore transmissivity was estimated for 

the wells using discharge and transient-drawdown data with 

AQTESOLVE software to visually match the straight-line 

solution of the Cooper-Jacob method (Cooper and Jacob, 

1946). The specific capacities [discharge (Q) divided by drawdown (s)] of these analyzed wells were regressed against their 

respective transmissivity estimates to establish a relation that 

could be used to estimate the wellbore transmissivity for those 

wells in which sufficient transient drawdown data were not 

available. The empirical relation between specific capacity and 

transmissivity for 29 selected wells at the Shenandoah Road 

Superfund Site was log-normally distributed and, therefore, 

required a log-log plot to produce a normal distribution for 

transmissivity. The equation of the best-fit trendline (fig. 2) is

T=122.73(Q/s-0.049)1.0082 , (1)

where

T is transmissivity, in feet squared per 

day, and

Q/s is specific capacity, in gallons per 

minute per foot of drawdown, 

measured after 30 minutes 

of pumping.

The correction factor 0.049 was subtracted from each 

30-minute drawdown to account for the effects of wellbore 

storage on the value of calculated transmissivity from shortduration single-well aquifer tests such as these. The coefficient of determination (R2

) is 0.76. The equation of best 

fit for the Shenandoah Road transmissivity data in relation 

to specific capacity data is comparable to similar equations 

compiled by Srivastav and others (2007) for various types of 

fractured rock. Transmissivities and specific capacities were 

calculated from single-well aquifer test results for 29 of the 43 

wells logged, and these data were used to create a predictive 

relation between overall transmissivity and specific capacity 

for the bedrock in this area (fig. 2). Wellbore transmissivity 

estimates ranged from 0.36 to 370 ft2

/day, and specific capacities ranged from 0.03 to 2.1 (gal/min)/ft. Two of the smallest 

estimated transmissivities, for wells Du-3265 (0.93 ft2

/d) and 

Du-3232 (0.36 ft2

/d), were eliminated from this dataset and 

figure 2 because their estimates were controlled by wellbore 

storage and not by aquifer properties. Ambient water levels, 

pumping rates, specific capacities, and transmissivities for the 

T = 122.73 (Q/s -0.049)1.0082

R2 = 0.7556

0.1

1

10

100

1,000

0.01 0.1 1 10

Specific capacity (Q/s), in gallons per minute per foot

Transmissivity (T),

in feet squared per day

Figure 2. Log-Log plot of specific capacity at 30 minutes versus 

transmissivity for logged wells at the Shenandoah Road National 

Superfund Site, Dutchess County, N.Y.

Shenandoah Road National Superfund Site wells are listed in 

table 3.

Estimates of Flow-Zone Transmissivity and Head

The transmissivity and hydraulic head of the flow zones 

were estimated by the flow-log analysis method described by 

Paillet (1998 and 2000). In this method, a best-fit match is 

developed between measured and model-calculated ambient 

and pumped flows by iterative adjustment of transmissivities 

and heads of individual flow zones in a numerical or analytical 

model. In similar hydrogeologic settings and wellbore conditions, the flow-log analysis method was shown to generally 

detect and quantify the hydraulic properties of flow zones 

whose transmissivities were within two orders of magnitude 

of the most transmissive zone penetrated in each given well 

(Paillet,1998 and Williams, 2008). A conceptual model of two 

flow zones in a well with heads under ambient and pumped 

conditions is shown in figure 3.

The analytical model FLASH (Flow Log Analysis of 

Single Holes; Day-Lewis and others, 2011) was used to solve 

for fracture-zone transmissivities and hydraulic heads. The 

FLASH model code, which is based on a multi-layer, analytical solution for steady-state radial flow to a single borehole 
16 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York Table 3. Ambient water levels, pumping rates, specific capacities, and transmissivities for selected wells at the Shenandoah Road National Superfund Site, Dutchess County, N.Y. [USGS, U.S. Geological Survey; WL, water level; Q, pumping rate; gal/min, gallons per minute; ft, feet; min, minutes; N/A, not applicable; DD, drawdown; Q/s - 30min, specific capacity after pumping 30 minutes; AQTESOLVE T, transmissivity estimated using AQTESOLVE software; (gal/min)/ft, gallons per minute per foot of drawdown, ft2/d, feet squared per day. Trendline T estimates calculated using the equation T= 122.73 (Q/s-.049)1.0082] County well number Site well number Date of test Ambient WL Q rate (gal/min) DD (ft) at 30 min Q/s-30min (gal/min)ft AQTESOLVE T (ft2/d) Lithology, remarks 3225 SRMW-1RB 1/10/2006 5.23 0.74 3.78** 0.19 18.45* Gneiss 3226 SRMW-2R 1/12/2006 44.8 3 5.68 0.53 197.8* 70 ft dolomite over 360 ft gneiss 3227 SRMW-18core 1/19/2006 6.69 1.7 7.07 0.24 51.15* Gneiss 3228 SRMW-19 11/15/2006 1.26 0.7 4.56 0.15 7.91* Dolomite over thin quartzite 3229 SRMW-20 11/17/2006 -11 60 65 ft of dolomite/60 ft of quartzite/170 ft of gneiss. No pumping test. Flows 60 gal/min 3230 SRMW-15 11/20/2006 56.99 1.2 1.95 0.61 30.89 Gneiss 3231 SRMW-14 11/21/2006 29.05 1.2 1.25 0.96 51.13 Dolomite 3232 SRMW-14A 11/28/2006 27.4 0.04 1.42 0.03 0.36 Dolomite. Recovery rate=0.04 gal/min. DD never stabilizes. 3233 SRMW-18C 12/8/2006 32.1 0.7 6.9 0.1 3.26 Gneiss 3234 SRMW-17 3/11/2007 18 0.67 7.72 0.09 5.98 Gneiss 3235 SRMW-12 12/14/2006 -0.02 0.9 1.62 0.56 34.25 Dolomite. Well blocked at 230 ft 3236 SRMW-18B 2/21/2007 17.75 0.6 3.28 0.18 16.87* Gneiss 3237 SRMW-18D 12/20/2006 76 0.6 6.08 0.1 12.93 Gneiss 3238 SRMW-18E 1/23/2007 19.92 2.2 1.1 2 295.4* Gneiss 3239 SRMW-18A 2/21/2007 30.49 N/A N/A N/A N/A Gneiss. Slug tested. No flowmeter logs. No pump test 3240 SRMW-18F 3/15/2007 35.7 1.3 0.77** 1.69 210.1* Gneiss 3241 SRMW-11 3/14/2007 10.82 1.65 1.2 1.37 191.5 Dolomite 3242 SRMW-16 3/15/2007 28.7 0.8 1.72 0.46 33.4 Gneiss 3243 SRMW-12R 6/26/2007 Flowing 0.2 4.47 0.2 19.15* Dolomite. Well flowing. Recovery rate=0.20 gal/min 3244 SRMW-4 6/27/2007 2.23 1 1.02** 0.98 118.84* Dolomite 3245 SHN-472 8/25/2009 19.9 0.5 Dolomite. No pump test data 3246 BRB-005 8/27/2009 24.68 1 5.13 0.19 29.21 Gneiss 3247 BRB-003 8/28/2009 0.9 1.1 5.81 0.19 48.92* Gneiss

3248 SEY-004 8/31/2009 10.87 1.6 3.68 0.43 63.7 Gneiss

3249 SHN-589 9/1/2009 3.16 1.8 1.4 1.29 88.89 Gneiss

3250 SEY-006 9/2/2009 10.29 1.5 2.41 0.62 62.14 Gneiss

3251 BRB-014 9/3/2009 20.19 0.8 3.68 0.22 21.19* Gneiss
Geophysical Log Analysis 17

Table 3. Ambient water levels, pumping rates, specific capacities, and transmissivities for selected wells at the Shenandoah Road National Superfund Site, —ContinuedDutchess County, N.Y.[USGS, U.S. Geological Survey; WL, water level; Q, pumping rate; gal/min, gallons per minute; ft, feet; min, minutes; N/A, not applicable; DD, drawdown; Q/s - 30min, specific capacity after pumping 30 minutes; AQTESOLVE T, transmissivity estimated using AQTESOLVE software; (gal/min)/ft, gallons per minute per foot of drawdown, ft2/d, feet squared per day. Trendline T estimates calculated using the 

equation T= 122.73 (Q/s-.049)1.0082]

County Site Ambient Q rate DD (ft) at Q/s-30min AQTESOLVE T well Date of test Lithology, remarks well number WL (gal/min) 30 min (gal/min)ft (ft2/d) number

3252 SEY-005 10/29/2009 3.62 1.15 3.44 0.33 25.83 Thin dolomite over thick gneiss3253 STN-051 10/30/2009 98.81 1 1.51 0.66 77.97* Gneiss

3254 GRF-007 10/13/2009 33.37 0.65 9.08 0.07 1.8 Shaley dolomite3255 EHC-002 10/14/2009 27.21 0.8 5.72 0.14 5.23 Gneiss3256 TWN-134 10/15/2009 flowing 2.8 6.54 0.43 90.38 Dolomite over quartzite; flowing at 1 gal/min 

3257 CHN-472 10/19/2009 10.46 1.1 Sand and gravel over dolomite. No pump test data3258 SHN-478 10/19/2009 34.84 0.9 0.43 2.09 366 Dolomite and shale alternating3259 BRB-006 10/20/2009 29.09 1.1 2.82 0.39 72.16 Gneiss3260 SHN-603 10/21/2009 2.8 2.4 3.44 0.7 28.06 Gneiss 3261 SHN-499 10/22/2009 32.96 0.25 2.24** 0.11 7.81* Gneiss

3262 BRB-011 10/26/2009 4.66 1 7.84 0.13 5.38 Gneiss 3263 BRB-009 10/27/2009 10.8 1 6.56 0.15 3.28 Gneiss3264 BRB-007 10/28/2009 3.62 1 6.98 0.14 30.13 Gneiss3265 JCK-117 1/20/2010 3.29 0.1 2.8 0.03 0.93 Dolomite over thin gneiss. Recovery rate is 0.1 gal/min 3266 SEY-007 1/18/2010 5.75 1 2.79 0.36 74.97 Dolomite/quartzite/gneiss 3267 SHN-591 1/21/2010 1.3 3 3.58 0.84 113.8 Gneiss; flowing at 2 gal/min

* Transimissivity estimated through trendline relationship** Estimated drawdown at 30 minutes.
18 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York Depth

Vertical Flow

A. Flowmeter log B. Ambient condition C. Stressed (pumped) condition

hw

a

Qa

1

Qa

2

hw

s

Qs

1

Qs

2

ho

1

h

o

2

h

o

1

ho

2

Fracture 1

Fracture 2

Fracture 1

Fracture 2

pump

Figure 3. Conceptual model of two flow zones in a well with heads under ambient and pumped conditions.

(the Thiem equation), is embedded within Microsoft Excel. 

The code solves a series of Thiem equations (fig. 3) that t

assume radial flow under equilibrium conditions. The series u

includes equations to represent the flow to (or from) the l

borehole from each flow zone under ambient and stressed 

conditions. This approach is easily implemented in Excel and 

facilitates the use of the Excel solver for automated model d

calibration. However, this approach requires a radius of influence (r0

) to solve for transmissivity or a total transmissivity to i

solve for r0

. The total wellbore transmissivity was estimated f

for each well on the basis of the Cooper-Jacob method or v

empirical relation as previously discussed. p

The analytical model used to iteratively solve for indi- 5

vidual fracture-zone transmissivities is a version of the Thiem u

equation. e

2πT T factor total a

a ( ) h h − 0

Qi = i w i and (2)

( ) r ln 0

rw

2πT T factor total s ( ) h h0

Qs i w − i

i = − , (3)

( ) r ln 0

rw

where,

Qa

i is the ambient flow for zone i,

Qs

i is the stressed flow for zone i,

T factor

i is the fraction of total transmissivity in zone i,

ha

w is the water level in the well under ambient 

conditions,

hs

w is the water level in the well under stressed 

conditions,

 rw is the radius of the well,

 r0

 is the radius of influence, Figure 4. Frequency distribution of estimated transmissivity of 

flow zones penetrated by wells at the Shenandoah Road National 

Superfund Site, Dutchess County, N.Y.

h0

i is the far-field head in zone i, and

Ttotal is the total transmissivity for the well.

The model-calculated wellbore flows and the estimated 

ransmissivity and hydraulic-head differences for the individal fracture zones are presented with the suite of geophysical 

ogs for each well in appendix 1.

The distribution of the transmissivity of the individual 

water-bearing fracture zones in the logged wells at the Shenanoah Road National Superfund Site appears to be approximately log-normal, as seen in a frequency distribution plot 

n figure 4. The transmissivities of 95 individually identified 

racture zones ranged from 0.25 to 340 ft2

/d, with a median 

alue of 6.7 ft2

/d. Most of the individual fracture zones are 

resent at depths of 300 ft or less as shown in figure 5. Figure 

 also shows that most of the transmissivities for fractures 

p to 300 ft deep range over two orders of magnitude—genrally from 1 to 100 ft2

/d. The three highest fracture-zone 

0

5

10

15

20

25

30

0 0.5 1 1.5 2 2.5

Logarithm of estimated transmissivity of flow zones,

in feet squared per day

Number of flow zones
Summary 19

Figure 5. Depths of individual 

fracture zones versus estimated 

fracture zone transmissivity for 

wells logged at the Shenandoah 

Road National Superfund Site, 

Dutchess County, N.Y.

0

100

200

300

400

500

600

0.1 1.0 10.0 100.0 1,000.0

Depth below land surface, in feet

Estimated transmissivity of fracture zones, in feet squared per day

transmissivities (340, 190, and 208 ft2/d) display a wide range 

of depths—62, 230, and 430 ft, respectively (fig. 5).

The composite hydraulic head of a well is the transmissivity-weighted average of the individual fracture-zone heads 

(Bennet and others, 1982). The difference between estimated 

individual fracture-zone heads and the composite head in each 

well ranged from less 0.01 to more than 10 ft. The relation 

between fracture-zone hydraulic-head differences estimated 

using the analytical model and those measured through 

discrete-zone monitoring installations is presented in figure 6.

Some significant error in this comparison arises from 

the fact that the estimated heads are representative of the 

time of logging, whereas individual head measurements of 

fracture-zone heads were made though Flute liner ports or in 

reconstructed residential wells, often at a different time of the 

Figure 6. Comparison of estimated hydraulic-head difference 

to measured hydraulic-head difference for flow zones in 

logged wells at the Shenandoah Road National Superfund Site, 

Dutchess County, N.Y.

y = 0.6183(x)0.7489

0.00

0.01

0.10

1.00

10.00

100.00

0.01 0.10 1.00 10.00

Estimated fracture-zone hydraulic-head difference, in feet

Measured fracture-zone hydraulic-head

difference, in feet

year than the flow logging. Composite wellbore and fracturezone heads on Shenandoah Mountain display seasonal swings 

on the order of tens of feet and respond rapidly to recharge 

events, thus compounding the problem of comparing estimated 

and measured heads. Given these limitations, it appears that 

the flow-log method generally provides an order of magnitude 

estimate for the difference between fracture-zone hydraulic 

heads and the composite head. 

Online Geophysical Log Archive

The USGS New York Water Science Center has developed an online geophysical log archive where the logs and 

log analysis of the Shenandoah Road Superfund site wells, as 

well as many others throughout the State, can be viewed or 

downloaded. The URL for the website is http://ny.water.usgs.

gov/maps/geologs/.

The locations of the Shenandoah Road National Superfund Site wells are shown on the index map. The user can 

zoom-in to the well cluster located just east of Fishkill, 

N.Y., to expand the view of the wells logged. Clicking on 

an individual well will bring up a menu of the available log 

formats, which are LAS, PDF, and WellCad Reader. WellCad 

Reader is available online free of charge at http://www.alt.lu/

downloads.htm.

Summary

From 2006 through 2010, the U.S. Geological Survey 

collected geophysical logs for 20 test wells and 23 residential 

wells at the Shenandoah Road National Superfund Site in 

Dutchess County, New York, for a study conducted in cooperation with the U.S. Environmental Protection Agency, Region 

2, as part of an Interagency Agreement to provide geophysical 
20 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York

and hydrogeologic technical support. The logs collected 

included caliper, gamma, acoustic and optical televiewer, 

deviation, electromagnetic-induction, magnetic-susceptibility, 

fluid-property, and vertical flow under ambient and pumped 

conditions. The geophysical logs were analyzed, along with 

drilling logs, to characterize the lithology, fabric, fractures, 

and flow zones penetrated by the wells. Flow logs and singlewell aquifer test data were analyzed to estimate the transmissivity and hydraulic heads of the individual fracture zones 

penetrated by the wells. The results of the geophysical-log 

analysis were used in the design of discrete-zone monitoring 

installations in the test wells and selected residential wells. 

Most of the test and residential wells penetrate the Hudson Highlands Complex gneisses or Wappinger Group dolostones. Some wells penetrate both the dolostone and gneiss. 

The bedrock fabric, which reflects the regional northeastsouthwest structural geology, as well as localized folding, 

includes foliations in the gneiss and bedding in the dolostone. 

Many fractures were oriented along the bedrock fabric, and 

many others are orthogonal to the fabric. 

Total wellbore transmissivity of the wells was estimated 

from short-term, single-well aquifer test data through the use 

of the Cooper-Jacob analytical solution. An empirical relation 

was established to estimate total wellbore transmissivity from 

specific-capacity data for those wells with insufficient transient drawdown measurements. Wellbore transmissivity estimates ranged from 0.36 to 370 feet squared per day (ft2

/day), 

and specific capacities ranged from 0.03 to 2.1 gallons per 

minute per foot [(gal/min)/ft]. 

Transmissivity and hydraulic heads of individual fracture 

zones were estimated from the total wellbore transmissivity 

and flow logs through use of an analytical model based on 

the Thiem equation. The model-estimated transmissivity of 

95 fracture zones delineated in the 43 wells ranged from 0.25 

to 340 ft2

/d, with a median value of 6.7 ft2/d. The differences 

between model-estimated fracture-zone heads and the composite heads in each well ranged from less 0.01 to more than 10 ft. 

Flow-log analysis generally provided an order of magnitude 

estimate for the fracture-zone hydraulic-head difference on the 

basis of a comparison of estimated and measured values.

Selected References

Bennett, G.D., Kontis, A.L., and Larson, S.P., 1982, Representation of multiaquifer well effects in three-dimensional 

ground-water flow simulation: Ground Water, v. 20, no. 3, 

p. 334–341.

Connally, G.G., 1980, Reconnaissance surficial geologic map 

of the Hopewell Junction 7.5-mi. quadrangle: New York 

State Geological Survey Open-File Report no.2gk561, 1 

sheet, 1:24,000.

Connally, G.G., and Sirkin, L.A., 1986, Woodfordian ice 

margins, recessional events, and pollen stratigraphy of the 

mid-Hudson valley, in Cadwell, D.H., ed., The Wisconsinan 

stage of the First Geological District, eastern New York: 

New York State Museum Bulletin no. 455, p. 50–72.

Cooper, H.H., Jr., and Jacob, C.E., 1946, A generalized graphical method for evaluating formation constants and summarizing well-field history: American Geophysical Union 

Transactions, v. 27, no. 4, p. 526–534.

Dana, J.D., 1872, Green Mountain geology—the quartzite of 

Poughquag, Dutchess County, New York: American Journal 

of Science, Series 3, v. 3, p. 253–256.

Dana, J.D., 1879, On the Hudson River age of the Taconic 

schists and on the dependent relations of the Dutchess 

County and western Connecticut limestone belts: American 

Journal of Science, Series 3, v.17, p. 375–388 and v.18, 

p. 61–64.

Day-Lewis, F.D., Johnson, C.D., Paillet, F.L., and Halford, 

K.J., 2011, A Computer Program for Flow-Log Analysis 

of Single Holes (FLASH): Groundwater, V. 49, no. 6, p. 

926–931 accessed January 11, 2013 at http://water.usgs.gov/

ogw/flash/FLASH-v1.0.pdf.

Dwight, W.B., 1887, Recent explorations in the Wappinger 

Valley limestones of Dutchess County, NY, No. 6: American 

Journal of Science, Series 3, v. 34, p. 139–153.

Fisher, D.W., 1968, Draft geologic map of the Hopewell 

Junction 7.5-min. quadrangle: New York State Geological 

Survey Open-File No. 1gG744, 3 sheets, 1:24,000 scale.

Fisher, D.W., 1977, Correlation of the Hadrynian, Cambrian, 

and Ordovician rocks in New York State: New York State 

Museum and Chart Series no. 25, 75 p., 5 sheets.

Fisher, D.W., Isachsen, Y.W., and Rickard, L.V., 1970, Geologic map of New York: New York Museum and Science 

Service Map and Chart Series No. 15, 5 sheets, 1:250,000 

scale.

Fisher, D.W., and McLelland, J.M., 1975, Stratigraphy and 

structural geology in the Amenia-Pawling valley, Dutchess 

County, New York, in Ratcliffe, N.M., ed., Guidebook for 

field trips in western Massachussetts, northern Connecticut, 

and adjacent areas of New York: New England Intercollegiate Geological Conference, 67th annual meeting, October 

10-12, 1975, Trip C-10, p. 280–312.

Fisher, D.W., and Warthin, A.S. Jr., 1976, Stratigraphic and 

structural geology in western Dutchess County, New York, 

in Johnsen, J.H., ed., Guidebook to field excursions: 48th 

Annual Meeting of the New York State Geological Association, October 15-17, 1976, Vassar College, Poughkeepsie, 

New York, Trip B-6, p B6-1– B6-36.
Selected References 21

Fluhr, T.W., 1931, Geology of the Fishkill area, New York—a 

report prepared for the Board of Water Supply, City of New 

York: New York State Geological Survey Open-File No. 

6mF302, 8 p.

Gerber, R.G., 1982, Reconnaissance surficial geologic map of 

the Hopewell Junction 7.5-min. quadrangle: Unpublished 

map on file with the U.S. Geological Survey, Troy, N.Y., 

1:24,000 scale.

Gordon, C.E., 1911, Geology of the Poughkeepsie Quadrangle: New York State Museum Bulletin No. 148, 121 p.

Groundwater Sciences Corporation, 2012, Shenandoah Road 

groundwater contamination Superfund site remedial investigation report: Groundwater Sciences Corp., Harrisburg, 

Pa., v. 1 (text and tables), 222 p., v. 2 (figures, plates, and 

appendices), 57 p., 8 CD-ROMs.

Helenek, H.L., 1972, Bedrock geology of the Hopewell Junction, NY 7.5-min. quadrangle—a preliminary report: New 

York State Geological Survey Open-File No.1g274, 13 p., 

1 sheet, 1:24,000 scale.

Helenek, H.L., and Mose, D., 1976, Structure, petrology, and 

geochronology of the Precambrian rocks of the Hudson 

Highlands, in Johnsen, J.H., ed., Guidebook to field excursions: 48th Annual Meeting of the New York State Geological Association, October 15-17, 1976, Vassar College, 

Poughkeepsie, New York, Trip B-1, p B1-1 – B1-27.

Hess, A.E., 1982, A heat-pulse flowmeter for measuring low 

velocities in boreholes: U.S. Geological Survey Open-File 

Report 82–699, 44 p.

Holzwasser, F., 1926, Geology of Newburgh and vicinity: 

New York State Museum Bulletin no. 270, 95 p.

Huntley, David, Nommensen, Roger, and Steffey, Duane, 

1992, The use of specific capacity to assess transmissivity 

in fractured-rock aquifers: Ground Water, v. 30, no. 3, p. 

396–402.

Johnson, C.D., Day-Lewis, F.D., Paillet, F.L., and Halford, 

K.J., 2009, FLASH-a program for flow log analysis of 

single holes (poster): EPA National Ground Water Forum 

and U.S. Geological Survey Toxics Meeting in San Diego, 

Calif., January 2009.

Keys, W.S., 1990, Borehole geophysics applied to groundwater investigations: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 2, chap. E2, p. 150.

Knopf, E.B., 1946, Stratigraphy of the lower Paleozoic rocks 

surrounding Stissing Mountain, Dutchess County, New 

York (abs.): Geological Society of America Bulletin, v.57, 

p. 1211–1212.

Moore, R.B., LaFleur, R.G., and others, 1982, Geohydrology 

of the valley-fill aquifer in the Sprout and Fishkill Creeks 

area, Dutchess County, N.Y.: U.S. Geological Survey OpenFile Report 82–81, 6 sheets, 1:24,000 scale.

Offield, T.W., 1962, Geology reconnaissance maps, southern 

portion of the Hopewell Junction 7.5-min. quadrangle: 

New York State Geological Survey Open-File No.1gB660, 

2 sheets, 1:24,000 scale.

Paillet, F.L., 1998, Flow modeling and permeability estimation 

using borehole flow logs in heterogeneous fractured formations: Water Resources Research, v. 34, no. 5, p. 997–1010.

Paillet, F.L., 2000, A field technique for estimating aquifer 

parameters using flow log data: Ground Water, v. 38, no. 4, 

p. 510–521.

Paillet, F.L., 2001, Hydraulic head applications of flow logs 

in the study of heterogeneous aquifers: Groundwater, v. 39, 

no. 5, p. 667–675.

Ratcliffe, N.M., and Burton, W.C., 1990, Bedrock geologic 

map of the Poughquag quadrangle, New York: U.S. Geological Survey Quadrangle Map GQ–1662, scale 1:24,000.

Reynolds, R.J., and Calef, F.J., III., 2010, Hydrogeologic 

data update for the stratified-drift aquifer in the Sprout and 

Fishkill Creek valleys, Dutchess County, New York: U.S. 

Geological Survey Scientific Investigations Map 3136, 

4 sheets, 1:24,000, accessed January 11, 2013, at http://

pubs.usgs.gov/sim/3136.

Simmons, E.T., Grossman, I.G., and Heath, R.C., 1961, 

Ground-water resources of Dutchess County, New York: 

New York State Department of Conservation Bulletin 

GW–43, 82 p.

Snavely, D.S., 1980, Ground-water appraisal of the FishkillBeacon area, Dutchess County, New York: U.S. Geological 

Survey Open-File Report 80–437, 14 p.

Srivastav, S.K., Lubczynski, M.W., and Biyani, A.K., 2007, 

Upscaling of transmissivity derived from specific capacity—a hydrogeomorphological approach applied to the 

Doon Valley aquifer system in India: Hydrogeology Journal, 

v. 15, p. 1251–1264.

U.S. Environmental Protection Agency, 2001, NPL site narrative for Shenandoah Road groundwater contamination: 

U.S. Environmental Protection Agency Region 2, accessed 

January 11, 2013, at http://www.epa.gov/superfund/sites/

npl/nar1628.htm.

U.S. Environmental Protection Agency, 2010, Shenandoah 

Groundwater Contamination Superfund Site, New York 

factsheet: U.S. Environmental Protection Agency Region 2, 

accessed January 11, 2013, at http://www.epa.gov/region2/

superfund/npl/0204269c.pdf.
22 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York

Walcott, C.D., 1891, Overlap relations at the base of the Paleozoics in the northern Appalachians: Bulletin of the Geological Society of America, v. 2, p. 163–164.

Williams, J.H., 2008, Flow-log analysis for hydraulic characterization of selected test wells at the Indian Point Energy 

Center, Buchanan, New York: U.S. Geological Survey 

Open-File Report 2008–1123, 30 p., accessed January 11, 

2013, at http://pubs.usgs.gov/of/2008/1123.

Williams, J.H., and Johnson, C.D., 2000, Borehole-wall imaging with acoustic and optical televiewers for fractured-bedrock aquifer investigations, in Proceedings of the 7th minerals and geotechnical logging symposium: Golden, Colo., 

Minerals and Geotechnical Logging Society, p. 43–53.

Williams, J.H., and Lane, J.W., 1998, Advances in borehole 

geophysics for groundwater investigations: U.S. Geological 

Survey Fact Sheet 002–98, 4 p.

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borehole flowmeter—description and application: Ground 

Water Monitoring and Remediation Review, v. 15, no. 4, 

p. 138–147.
Appendix 1 23

Appendix 1. Geophysical Log Analysis of Three Selected

Wells at the Shenandoah Road National Superfund Site, 

Dutchess County, N.Y.

Appendix 1 25

Appendix 1. Geophysical Log Analysis of Three Selected Wells at the

Shenandoah Road National Superfund Site, Dutchess County, N.Y.

The geophysical logs and analysis of the logs for three selected wells at the Shenandoah Road National Superfund site in 

Dutchess County, New York, are presented below. Well Du-3246 (BRB-5) is a contaminated residential well that was logged by 

the U.S. Geological Survey (USGS) and later converted for monitoring purposes by Groundwater Sciences Corporation (GSC). 

Wells Du-3241 (SRMW-11) and Du-3230 (SRMW-15) are test wells that were drilled for the purpose of the Remedial Investigation/Feasability Study (RI/FS) investigation and were later fitted with multiple discrete-zone monitoring systems to facilitate the 

monitoring of head and water quality at individual flow zones. 

Du-3246 (BRB-5)

Well Du-3246 is located downslope from the source area 

for the Shenandoah Road National Superfund site. The well 

is 276 feet (ft) deep and is completed in Hudson Highlands 

Complex gneisses. The bedrock fabric identified on the optical televiewer log generally dips less than 30 degrees with 

variable dip directions. Fractures identified on the acoustic 

and optical televiewers are sparse between 90 and 240 ft. 

Open fractures appear to be present at 36, 86, 242, and 259 ft. 

Iron staining, clearly visible at the 86- and 259-ft fractures, 

indicates possible fluid movement and is indicative of a 

transmissive fracture. The ambient temperature log shows a 

gradient less than the geothermal gradient, which is consistent 

with the presence of wellbore flow. The fluid-conductivity 

log shows a deflection at the 86-ft fracture zone under ambient and pumped conditions, indicative of water inflow. The 

flowmeter measurements and interpreted flow under ambient 

and pumped conditions indicate upflow under both conditions, 

starting from the fracture zone at 259 ft with small additional 

inflows from zones at 242 ft and 86 ft. All of the upflow exits 

the wellbore at the fracture zone at 36 ft under ambient conditions, and a fraction of the upflow exits at this fracture zone 

under pumped conditions. The estimated transmissivities from 

the flow-log analysis are 9.2 feet squared per day (ft2

/d) for 

the 259-ft fracture, 6.7 ft2

/d for the 242-ft zone, 2.7 ft2/d for 

the 86-ft zone, and 10.7 ft2

/d for the 36-ft zone. The estimated 

heads at each flow zone indicate similar heads are present at 

the two lowermost zones (242 and 259 ft), a slightly lower 

head at the 86-ft zone, and a much lower head at the 36-ft 

zone. The head differences estimated through flow analysis are 

consistent with those measured following reconstruction of the 

well into a dual-interval monitoring well. 

Du-3241 (SRMW-11)

Well Du-3241 is on Townsend Road, just north of the 

eastbound lane of Interstate 84 and northeast of the Shenandoah Road contamination source. This test well is 500 ft deep 

and penetrates dolostones of the Poughquag Quartzite of the 

Wappinger Group and terminates in the Hudson Highlands 

Complex gneisses. The reported blown yield of the well was 

50 gallons per minute (gal/min). Increases in blown yield were 

reported from a fracture near 125 ft (below land surface) and 

multiple fractures between 300 and 450 ft. The bedding in the 

dolostones identified on the optical televiewer log generally 

dips to the northeast at less than 30 degrees. The foliation in 

the gneiss generally dips east-southeast at 30 to 60 degrees. 

Fractures identified on the acoustic and optical televiewers are 

sparse. Open fractures appear to be present at 126, 236, 293, 

321, 387, and 474 ft. The ambient temperature shows a change 

in slope at the 321-ft fracture zone, indicating a decrease in 

ambient flow. The ambient and pumped fluid-conductivity and 

temperature logs depart from each other between the 126-ft 

fracture zone and the 293-ft fracture zone, indicating a possible change in flow direction. Subtle slope changes on the 

ambient and pumped fluid-conductivity logs at the 387- and 

474-ft zones indicate the possibility of slight inflows. The 

flowmeter measurements and interpreted flow under ambient 

conditions indicate downward flow from the 126-ft fracture 

zone. The downward flow slightly decreases at the 236-ft fracture zone, slightly increases at the 293-ft fracture zone, and 

finally exits at the 321-ft fracture. The ambient flowmeter log 

indicates no measurable flow between 321 ft and the bottom of 

the well. Wellbore flow is reversed when the well is pumped 

at 1.6 gal/min. The pumped flow log indicates very slight 

upward flow starting at the 474-ft zone with large increases 

at 293- and 126-ft zones and a small increase at the 236-ft 

zone. The estimated fracture transmissivities from the flow-log 

analysis are 54 ft2

/d for the 126-ft zone, 33 ft2/d for the 236-ft 

zone, 75 ft2

/d for the 293-ft zone, 28 ft2/d for the 321-ft zone, 

and 1ft2

/d or less for the 387- and 473-ft zones. The estimated 

heads at individual flow zones indicate lower heads at the 

321- and 236-ft zones and higher heads at the 293- and 126-ft 

zones. The head differences estimated through flow analysis 

generally were consistent with those measured following 

installation of the multiple discrete-monitoring system in the 

test well.

Du-3230 (SRMW-15)

Well SRMW-15 (DU-3230) is a test well located on the 

south side of Shenandoah Road at the nose of Shenandoah 

Mountain. The well is 500 ft deep and penetrates Hudson 

Highlands Complex gneisses. Total blown yield reported for 

the well was 20 gal/min with essentially all of the yield from 
26 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York

multiple fractures near 350 ft and only a small amount from 

a fracture near 200 ft. The foliation in the gneiss identified on 

the optical televiewer above 260 ft is variable. Below 260 ft, 

the foliation generally dips northwest to east at less than 

60 degrees. Fractures identified on the acoustic and optical 

televiewers generally dip to the southeast or northwest at variable angles. Open fractures appear to be present at 86, 119, 

200, 233, 323, and 362 ft. The ambient fluid-conductivity log 

indicates that the fluid conductivity of the wellbore water is 

significantly higher [up to 2, 300 microsiemens per centimeter 

(μS/cm)] above the 200-ft zone than below the zone (about 

230 μS/cm). Under pumping conditions, the change from 

lower to higher fluid conductivity occurs at the 119-ft zone. 

The well is suspected of being contaminated by road 

salt because it is located close to Shenandoah Road, near the 

crest of a steep hill. A chloride log collected under ambient 

conditions shows that dissolved chloride concentrations were 

high, about 740 milligrams per liter (mg/L), from the surface 

casing down to the 200-ft zone, after which concentrations 

decreased with depth to about 8.5 mg/L, thus seeming to 

confirm the presence of road salt in shallow groundwater at 

this location. Two point samples, collected at 180 and 260 ft 

under ambient conditions, yielded chloride concentrations of 

734 and 8.46 mg/L, respectively, and were used to calibrate 

the chloride logs. Moreover, a downhole grab sample collected 

by GSC at 197 ft had a dissolved sodium concentration of 199 

mg/L and a dissolved calcium concentration of 61.8 mg/L, 

both indicators of the presence of sodium chloride and calcium 

chloride salts used in road salting applications (GSC, written 

commun., 2008). 

Flow measurements at 21 locations under ambient conditions reveal a slight downward flow with a small increase from 

the 86- and 119-ft fractures; the downward flow exited at the 

200-ft zone. At greater depth within the borehole, the ambient flowmeter log shows upward flow emanating from the 

362-ft fracture, an additional inflow from the 323-ft fracture, 

a slight loss of water to the 233-ft fracture, and finally all of 

the upward flow exiting at the 200-ft fracture. This condition 

is known as convergent wellbore flow. The ambient flowmeter 

log shows no measurable flow from 362 ft to the bottom of 

the hole. Pumping the borehole at 1.2 gal/min, reverses the 

downward flow, and the pumped-well flowmeter log indicates 

upward flow starting at the 362-ft zone, a substantial inflow 

from the 323-ft zone, small losses to the 233- and 200-ft zone, 

and finally small inflows from the 119- and 86-ft zones. The 

estimated fractures transmissivities are 3.9 ft2

/d for the 86-ft 

zone, 4.8 ft2

/d for the 200-ft zone, 7.9 ft2/d for the 323-ft 

zone, and 14.5 ft2

/d for the 362-ft zone. The transmissivities for the zones at 119 and 233 ft could not be determined 

but likely are less than 0.2 ft2

/d. The estimated heads at each 

individual zone indicate the lowest head occurred at the 200-ft 

zone with higher heads above at the 86- and 119-ft zones and 

lower heads at the 323- and 362-ft zones. The head differences 

estimated through flow analysis generally were consistent with 

those measured following installation of the multiple discretemonitoring system in the test well.
Appendix 1 27

Depth

1:475

Du 3246/BRB-005

Caliper

5 In

Gamma

0

ATV MN OTV MN Azimuth

0

Tilt

0 Deg

Fl cond amb

100

Temp amb

Fl cond pmp

100

Temp pmp

Fabric MN

0

Fracture MN

0

Head Diff

-10 Ft 

Trans

0.2

Litho Flow amb

-1.5 Gal/min

Flow pmp

-1.5 Gal/min

Packer

-10 ft

0

50

100150200250

300 90 90 7 1.5

1.5

20 10

10 200

200 9 360

Suite of geophysical and flowmeter logs for well Du-3246 (BRB-5), Shenandoah Road National Superfund Site, 

ork., New Y

Figure 1-1Duchess County
28 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York Depth

1:1000

Du 3241/SRMW 11

Caliper

5 In

Fracture log

0 Ft

Head diff Temp amb

Temp pmp

Fl cond amb

FL cond pmp

Fracture TN

0

Fabric TN

0

WL2-19-08

WL4-2-08 

WL7-22-08

WL9-4-08 

Yield

0 Ft

Trans

1

Gamma

0

Cond

0

OTV MN ATV MN Azimuth

0

Tilt

0 Deg

Litho Flow amb

-2 Gal/min

Flow pmp

-2 Gal/min

0

50

100150200250300350400450500

1 500

70

100 90 90 7 2 100 -2.5 2.5

2 -2.5 2.5

-2.5 2.5-2.5 2.5-2.5 2.5

200 350200 350

51 5351 53

360 5

Figure 1-2. Suite of geophysical and flowmeter logs for well Du-3241 (SRMW-11), Shenandoah Road National Superfund Site, Duchess County, New York.
Appendix 1 29

Depth

1:1000

Du 3230/SRMW 15

Gamma

0

ATV MN OTV MN Fabric MN 

0

Fl cond amb

Fl cond pmp

O2 amb

0 ppm

Temp amb 

50.2

Temp pmp

50.2

Trans

0.2

Head diff

-30

WL 4-2-08

-30

Caliper

6 In

Fracture MN

0

WL 2-19-08

-30

WL 7-22-08

-30

WL 9-4-08

-30

O2 pmp

0 ppm

Litho Cl amb 

240

Cl pmp

240 100

Azimuth

0

Tilt

0 Deg

Yield

0

Fracture log

0 1ft

Flow amb

-1.5 Gal/min

Flow pmp

-1.5 Gal/min

Cl amb sam p

-100

0

50

100150200250300350400450500

<

<

50 750 90 90 7 1.5

1.5

20 30

30303030

52.2

52.2

100 10

10

900

360 4

Figure 1-3. Suite of geophysical and flowmeter logs for well Du-3230 (SRMW-15), Shenandoah Road National Superfund Site, Duchess County, New York.
30 Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York

Explanation of Geophysical Log Column 

Headings 

Du 3230/SRMW 15 U.S. Geological Survey well number/Site 

well number 

Depth Depth, in feet below land surface

Litho Lithology; light green with dash and wavy line pattern 

indicates gneiss, white with stipple and dash pattern indicates 

quartzite, green with horizontal and angled line pattern indicates dolomite, and brown stipple and circle pattern indicates 

sand and gravel 

Yield Cumulative blown yield reported during drilling, in 

gallons per minute (gal/min)

Fractured Zone Fractured zone reportedly penetrated during 

drilling 

Gamma Gamma radiation, in counts per second

Cond Electromagnetic induction conductivity, in millisiemens per meter (mS/m)

Tadpole Fabric TN Tadpole plot of foliation or bedding oriented to True Geographic North, body of tadpole indicates dip 

angle and tail indicates dip direction 

Stereo Fabric TN Lower-hemisphere, Schmidt stereo plot of 

foliation or bedding oriented to True Geographic North 

OTV MN Optical televiewer; 360-degree optical image of 

borehole wall oriented to Magnetic North

Tadpole Fracture TN Tadpole plot of planar fracture oriented 

to True Geographic North, body of tadpole indicates dip angle 

and tail indicates dip direction; blue color indicates transmissive fracture based on flow-log analysis

Stereo Fracture TN Lower-hemisphere, Schmidt stereo 

plot of planar fracture oriented to True Geographic North; 

blue color indicates transmissive fracture, based on flow-log 

analysis

ATV MN Acoustic televiewer; 360-degree acoustic image of 

borehole wall oriented to Magnetic North

Caliper Caliper; borehole diameter, in inches 

Flow amb/pmp Flow, in gallons per minute; blue circle 

indicates ambient flow measurement with heat-pulse or electromagnetic flowmeter at specified depth; blue line indicates 

ambient flow based on flow-log analysis; red box indicates 

pumped flow measurement collected with heat-pulse or electromagnetic flowmeter at specified depth; red line indicates 

pumped flow based on flow-log analysis

Trans Estimated transmissivity of flow zone based on flowlog analysis, in feet squared per day

Head Diff 9-4-08 Difference between flow-zone head and 

composite head on indicated date, in feet; black square indicates estimated head difference based on flow-log analysis; 

variously colored segments indicate measured head difference 

from discrete-zone monitoring installation 

Fl cond amb/pmp Fluid conductivity, in microsiemens per 

centimeter (μS/cm); blue line indicates ambient and red line 

indicates pumped

Temp amb/pmp Temperature, in degrees Fahrenheit; blue 

line indicates ambient and red line indicates pumped

Cl amb/pmp Dissolved chloride concentration, in milligrams 

per liter (mg/L); blue line indicates ambient and red line indicates pumped; blue square indicates point sample

O2 amb/pmp Dissolved oxygen concentration, in milligrams 

per liter (mg/L); blue line indicates ambient and red line indicates pumped

Azimuth MN Direction of borehole deviation, in degrees 

from Magnetic North

Tilt Angle of borehole deviation, in degrees from vertical
Prepared by the Pembroke Publishing Service Center.

For more information concerning this report, contact:

Director

New York Water Science Center

U.S. Geological Survey

425 Jordan Road

Troy, NY 12180-8349

dc_ny@usgs.gov

or visit our Web site at:

http://ny.water.usgs.gov
Reynolds and others—Geophysical Analysis of Wells at the Shenandoah Road National Superfund Site, East Fishkill, New York—SIR 2014-5228

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20145228