U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2008–1123

Flow-Log Analysis for Hydraulic Characterization 

of Selected Test Wells at the Indian Point Energy 

Center, Buchanan, New York

Prepared in cooperation with the United States Nuclear Regulatory Commission
Cover. Photograph by Thomas J. Nicholson (U.S. Nuclear Regulatory Commission) of bedrock quarry southwest of Indian Point 

Energy Center, Buchanan, New York.
Flow-Log Analysis for Hydraulic 

Characterization of Selected Test 

Wells at the Indian Point Energy Center, 

Buchanan, New York

By John H. Williams

Prepared in cooperation with the United States Nuclear Regulatory Commission

U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2008–1123
ii

U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2008

For more information on the USGS--the Federal source for science about the Earth, its natural and living resources, 

natural hazards, and the environment:

World Wide Web: http://www.usgs.gov

Telephone: 1-888-ASK-USGS

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

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., online only.
iii

Figures

1–2. Maps showing—

1. Location of Indian Point Energy Center site, Buchanan, New York............................2

2. Location of selected test wells at the Indian Point Energy Center site......................3

3–5. Photographs showing—

3. Aerial view looking north of the Indian Point Energy Center site and location 

of selected test wells ..........................................................................................................4

4. View looking northeast of quarry exposure of carbonate bedrock with 

bedding and orthogonal fractures, Indian Point Energy Center site...........................5

5. Optical-televiewer (OTV) and acoustic-televiewer (ATV) logs of test well

MW-60 at the Indian Point Energy Center site: (A) interval from 52 to 57 feet 

below land surface, showing subhorizonal fractured zone, (B) interval from 

70 to 75 feet below land surface (with core sample from same interval), 

showing northwest-dipping orthogonal fractures, and (C) interval from 134 to 

139 feet below land surface, showing southeast-dipping bedding fracture.............5

6–7. Diagrams showing—

6. Relation between transmissivity of flow zones penetrated by selected test 

wells estimated from flow-log analysis and measured by hydraulic tests................7

7. Relation between hydraulic-head difference of flow zones penetrated by 

selected test wells estimated from flow-log analysis and measured in 

monitoring-well intervals....................................................................................................9

Contents

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

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

Description of Study Area and Hydrogeologic Setting ..................................................................1

Description of Wells .............................................................................................................................1

Description of Logs .......................................................................................................................................2

Flow-Log Analysis..........................................................................................................................................4

Selected Results of Aquifer and Tracer Tests...........................................................................................6

Summary..........................................................................................................................................................9

References Cited..........................................................................................................................................10

Appendix 1. Composites of Geophysical Logs, Transmissivity and Hydraulic-Head 

Difference Estimates and Measurements, and Selected Aquifer- and 

Tracer-Test Results for the Test Wells, Indian Point Energy Center Site, 

Buchanan, New York.........................................................................................................11

Table

1. Construction and hydrologic information for selected test wells, Indian Point 

Energy Center site, Buchanan, New York.................................................................................8
iv

Conversion Factors and Datum

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

 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 National Geodetic Vertical Datum of 1929 

(NGVD 1929).

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.

Abbreviations

ATV Acoustic televiewer 

GAI Geophysical Applications, Inc. 

GZA GZA GeoEnvironmental, Inc. 

NRC Nuclear Regulatory Commission

OTV Optical televiewer

USGS U.S. Geological Survey
Abstract

Flow logs from 24 test wells were analyzed as part of 

the hydraulic characterization of the metamorphosed and 

fractured carbonate bedrock at the Indian Point Energy Center 

in Buchanan, New York. The flow logs were analyzed along 

with caliper, optical- and acoustic-televiewer, and fluidresistivity and temperature logs to determine the character 

and distribution of fracture-flow zones and estimate their 

transmissivities and hydraulic heads. Many flow zones were 

associated with subhorizontal to shallow-dipping fractured 

zones, southeast-dipping bedding fractures, northwestdipping orthogonal fractures, or combinations of bedding and 

orthogonal fractures. Flow-log analysis generally provided 

reasonable first-order estimates of flow-zone transmissivity 

and head differences compared with the results of conventional 

hydraulic-test analysis and measurements. Selected results 

of an aquifer test and a tracer test provided corroborating 

information in support of the flow-log analysis.

Introduction 

Radionuclides have been detected in ground water 

sampled from metamorphosed and fractured carbonate 

bedrock at the Indian Point Energy Center in southeastern 

New York. In 2007, the U.S. Geological Survey (USGS) 

conducted a flow-log analysis of selected test wells to help 

characterize the hydraulics of fractured zones in the bedrock. 

The work was completed in cooperation with the U.S. Nuclear 

Regulatory Commission (NRC), which provided technical 

oversight of the investigation of ground-water contamination 

conducted by Entergy, Inc., the owner and operator of the 

site. This report describes and presents the flow-log method 

and integrated analysis of the flow logs with other supporting 

geophysical log and aquifer- and tracer-test data. The 

transmissivity and hydraulic head of flow zones estimated 

by the flow-log method are compared with those determined 

from hydraulic tests and measurements in corresponding 

test-well intervals isolated by inflatable straddle packers or as 

completed monitoring-well installations.

Flow-Log Analysis for Hydraulic Characterization of 

Selected Test Wells at the Indian Point Energy Center, 

Buchanan, New York 

By John H. Williams

Description of Study Area and 

Hydrogeologic Setting

The Indian Point Energy Center is the site of a nuclearpower plant in the Village of Buchanan in Westchester 

County, New York (figs. 1, 2, and 3). The site is within the 

Hudson Highlands physiographic province and is bordered on 

the west by the Hudson River. Land-surface altitude ranges 

from about 10 ft near the river to 140 ft above the National 

Geodetic Vertical Datum 1929 (NGVD 1929) in the eastern 

part of the site. 

The site is underlain by the Inwood Marble; these 

metamorphosed dolostones and limestones of CambroOrdovician age were extensively blast-excavated during plant 

construction. The Manhattan Schist unconformably overlies 

the Inwood Marble near the northern and eastern borders of 

the site. Bedding in the carbonate bedrock generally dips 30 

to 70 degrees to the southeast (figs. 4 and 5). Many fractures 

are oriented along bedding and orthogonal to bedding. 

Subhorizontal fractured zones commonly are present in the 

upper part of the bedrock. The shallow-dipping fractured 

zones, southeast-dipping bedding fractures, and northwestdipping orthogonal fractures along with other fractures with 

a range of orientations form an interconnected permeable 

network for ground-water flow. Where present, faults, 

including a north-south trending high-angle feature identified 

by Dames and Moore (1975), Ratcliffe and others (1983), 

and Barvenik and others (2008), locally may enhance or 

impede ground-water flow depending on the presence of 

clay-rich gouge. 

Description of Wells

Twenty-four test wells installed under the direction 

of GZA GeoEnvironmental, Inc. (GZA), consultant to 

Entergy, Inc., were selected by GZA for geophysical logging. 

Information on these test wells, including construction 

and water level, pumped rate, and drawdown at the time of 

logging, is presented in table 1. Well locations are shown 

in figures 2 and 3. The test wells were constructed as open 

holes below steel casing that was set into competent bedrock. 
2 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York

The test wells ranged from 30 to 340 ft deep, and had 4 to 

40 ft of casing. The test wells were cored 3.8 to 4 inches 

in diameter, except RW-1, which was drilled 6 inches in 

diameter. Hydrogeologic descriptions of the recovered core 

are presented in Barvenik and others (2008). After geophysical 

logging was completed, each test well was converted to a 

single- or multiple-interval monitoring-well installation by 

GZA. Hydraulic tests were completed by GZA either in the 

test well or in the completed monitoring-well installation. 

Description of Logs 

The geophysical logs were collected from November 

2005 to July 2007 by Geophysical Applications, Inc. (GAI) 

under the direction of GZA and included caliper, optical- and 

acoustic-televiewer, fluid-resistivity, temperature, and flow 

logs (app. 1). Information on geophysical logs and logging 

for ground-water investigations is presented in Keys (1990). 

The geophysical logs collected and analyzed in the present 

investigation are described briefly below. 

Caliper logs record the diameter of the borehole. Changes 

in borehole diameter are related to drilling and construction 

procedures and competency of bedrock. The caliper logs were 

collected with a spring-loaded, three-arm averaging tool, and 

were used to confirm test-well casing depths and diameters 

and to delineate fractures.

Optical-televiewer (OTV) and acoustic-televiewer (ATV) 

logs record 360-degree magnetically oriented images of 

the wellbore wall (Williams and Johnson, 2000). The OTV 

and ATV logs were used to characterize the distribution and 

orientation of planar fracture and bedding features intersected 

by the test wells. Planar fracture and bedding features were 

picked by GAI and their orientations were calculated and 

corrected for well deviation, which was determined from the 

three-axis fluxgate magnetometers and vertical inclinometers 

incorporated in the OTV and ATV tools. Dip azimuth and 

angle of the fracture and bedding features corrected from 

magnetic to true north are shown in tadpole plots and lowerhemisphere stereonet diagrams (app. 1). It should be noted that 

fracture delineation from OTV and ATV logs of near-vertical 

wells oversample low-angle fractures and undersample highangle fractures.

Base from U. S. Geological Survey

1:24,000 Peekskill and Haverstraw, NY

1957, Photorevised 1981

41°15'

NEW YORK

Westchester Co.

Site

Site area shown in figure 2

View shown in figure 4 41°16'

74°57'30" 74°55'

1 MILE

1 KILOMETER

0

0

Figure 1. Location of Indian Point Energy Center site, Buchanan, New York.
Description of Logs 3

Fluid-resistivity and temperature logs record the 

electrical resistivity and temperature of water in the test 

wells. Fluid resistivity is inversely related to the concentration 

of dissolved solids in the water. Slope changes in fluidresistivity and temperature logs, which were collected 

under ambient conditions, helped delineate zones of inflow 

to or outflow from the test wells. Collection of fluidresistivity and temperature logs under pumped conditions 

would have provided an additional level of enhancement in 

flow-zone delineation. 

Flow logs record the direction and rate of vertical flow 

in the well. Vertical flow occurs in wells that penetrate two 

or more flow zones under differing hydraulic head. Flow is 

from zones of higher head to zones of lower head. The water 

levels measured in the open-hole test wells are composite 

head values that reflect the transmissivity-weighted average 

of the hydraulic heads of the intersected flow zones (Bennett 

and others, 1982). Heads in inflow zones are higher than the 

composite water level, and outflow zones are lower than the 

composite water level.

Flow at selected depths in the test wells was measured 

with a heat-pulse flowmeter (Hess, 1982), which determines 

vertical flow based on the travel time of a thermal pulse 

between a set of upper and lower thermistors. To channel flow 

through the measurement throat, the flowmeter was used with 

a flexible rubber diverter fitted to the nominal well diameter. 

The heat-pulse flowmeter configured with a fully fitted 

diverter has a measurement range of 0.005 to 1.0 gal/min. 

Flow logs were collected in the test wells under ambient and 

pumped conditions, and the quasi-steady-state drawdown 

under the short-term pumped conditions was measured, which 

allowed for quantitative analysis and estimation of flow-zone 

transmissivity and head (Paillet, 1998 and 2000). In test wells 

MW-35 and MW-52, constant pumped rates and quasi-steadystate drawdowns were not obtained as a result of rapidly 

declining water levels. Although not attempted in the present 

investigation, quantitative flow-log analysis could have been 

applied in these test wells by use of the recovery and flow 

normalization method described by Paillet (2004).

Hudson River

N

0 100 200 FEET

MW-31

MW-32

MW-30 RW-1

MW-34 MW-35

MW-60

MW-57

MW-54

MW-52

MW-60 MW-66 MW-62

MW-58

MW-59

MW-63

MW-64

MW-65

MW-39

MW-53

MW-67

MW-46

MW-51

MW-40

EXPLANATION

Test well and site well identification

MW-55

Base from Barvenik and others (2008) 

0 50 METERS

MW-56

Figure 2. Location of selected test wells at the Indian Point Energy Center site.
4 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York

Flow-Log Analysis 

The distribution and character of fracture-flow zones 

intersected by the test wells were determined by the integrated 

analysis of the caliper, optical- and acoustic-televiewer, fluidresistivity, temperature, and flow logs (app. 1). One or more 

fracture features within each zone were designated as the 

hydraulically active fracture or fractures contributing to the 

measured ambient and pumped flows. Many flow zones were 

associated with subhorizontal to shallow-dipping fractured 

zones, southeast-dipping bedding fractures, northwestdipping orthogonal fractures, or combinations of bedding and 

orthogonal fractures (fig. 5). 

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 simulated ambient 

and pumped flows by iterative adjustment of flow-zone 

transmissivity and head in a numerical model. A unique 

inversion for zone transmissivity and hydraulic-head values 

is determined given two sets of flow logs and associated 

water levels collected under ambient and quasi-steady-state 

pumped conditions. 

The transmissivity and hydraulic-head differences 

determined by the flow-log analysis were compared with the 

results of hydraulic testing and hydraulic-head measurements 

reported by Barvenik and others (2008). The hydraulic tests 

MW-59

MW-40 MW-51

MW-54 MW-57 MW-46

MW-39

MW-65

MW-56

MW-35

MW-34

MW-53

MW-31

MW-32

MW-30 RW-1 MW-52 MW-55

MW-60

MW-67

MW-66

MW-62

MW-63

MW-58

N

EXPLANATION

Test well and site well identification

MW-60

Figure 3. Aerial view looking north of the Indian Point Energy Center site and location of selected test wells. (Photograph provided 

by Entergy, Inc.)
Bedding

fracture

Orthogonal

fracture

Flow-Log Analysis 5

Figure 5. Optical-televiewer (OTV) and acoustic-televiewer (ATV) logs of test well MW-60 at the Indian Point Energy Center 

site: (A) interval from 52 to 57 feet below land surface, showing subhorizonal fractured zone, (B) interval from 70 to 75 feet below 

land surface (with core sample from same interval), showing northwest-dipping orthogonal fractures, and (C) interval from 134 to 

139 feet below land surface, showing southeast-dipping bedding fracture.

Figure 4. View looking northeast of quarry exposure of carbonate bedrock with bedding and orthogonal fractures, Indian Point 

Energy Center site. (Photograph by Thomas J. Nicholson, NRC)

N E S W N N E S W N N E S W N N E S W N N E S W N N E S W N

OTV ATV OTV ATV OTV ATV

52

53

54

55

56

57

70

71

72

73

74

75

134

135

136

137

138

139

A B C

DEPTH BELOW LAND SURFACE, IN FEET

CORE
6 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York

were conducted in test-well intervals isolated by inflatable 

straddle packers or as completed monitoring-well installations. 

More than 90 percent of the 76 hydraulic tests used in the 

comparison were slug tests analyzed by the Hvorslev (1951) 

method, and the rest were extraction tests analyzed by the 

Theis (1935) method. The hydraulic-test data and their 

analysis are presented in more detail by Barvenik and others 

(2008). The hydraulic heads used in the comparison were 

measured in the completed monitoring-well installations. 

Average hydraulic heads on February 12, 2007 (Barvenik 

and others, 2008) were used in the comparison for all 

monitoring-well installations except MW-63 and MW-67. 

Average hydraulic heads on June 1, 2007, and August 28, 

2007 (Barvenik and others, 2008), respectively, were used 

for wells MW-63 and MW-67 because complete sets of head 

measurements were not available for February 12, 2007. 

When compared with the hydraulic-test results, the 

flow-log analysis detected 74 percent of flow zones where 

transmissivities were within two orders of magnitude of the 

most transmissive zone penetrated by each given test well. 

This comparison of results from hydraulic-test and flow-log 

methods is consistent with that reported by Paillet (1998) for 

crystalline bedrock at the USGS fractured-aquifer research site 

in Mirror Lake, New Hampshire. 

Measurable ambient flow indicating differences in 

hydraulic heads in two or more penetrated flow zones was 

observed in 16 of the logged test wells. Flow was downward 

in eight wells (MW-31, -32, -40, -51, -54, -55, -58, and -65), 

upward in four wells (MW-59, -63, -66, and -67) and both 

upward and downward in four wells (RW-1 and MW-39, -56, 

and -57). Even though hydraulic head is transient in nature 

and the flow logs and head measurements were not collected 

at the same time, observed flow directions in the test wells 

generally were consistent with the subsequently measured 

head differences; that is, flow was from zones of higher head 

to zones of lower head. 

Flow-log analysis generally provided reasonable 

first-order estimates of flow-zone transmissivity and head 

differences in comparison with the results of the hydraulic-test 

analysis and measurements. The logs of transmissivity values 

estimated by the flow-log analysis and those measured by the 

hydraulic tests are significantly correlated (fig. 6). The fitted 

relation is

log THT = 0.34 + 0.64 log TFL , (1)

where

THT is transmissivity of tested interval measured 

by hydraulic-test methods, in feet squared 

per day; 

and

TFL is transmissivity of flow zone estimated by 

flow-log method, in feet squared per day.

Selected results from test wells MW-40 and MW-54, 

which are identified in figure 6, were deemed questionable 

and not included in the fitted relation. These and, most likely, 

an undetermined number of additional outliers are related 

to the limitations inherent in flow logging and in hydraulic 

testing using inflatable packers. The apparent overestimation 

of transmissivities by hydraulic testing in test well MW-54 

is believed to be the result of an inability to obtain leaktight seals between the packers and the wellbore wall, which 

allowed leakage into adjacent, highly fractured intervals of the 

wellbore. This conclusion is supported by analysis of the head 

response above and below the test interval. The reason for the 

order-of-magnitude discrepancy between the transmissivity 

estimates for the shallowest flow zone in test well MW-40 

is unclear. Because the shallowest flow zone is near the 

water surface, which is not uncommon, it was not feasible to 

make a measurement above the zone to confirm the pumped 

rate. The uppermost measurement under pumped conditions 

indicated downward flow, so the assumption was made that 

all the pumped flow was contributed by the shallowest zone, 

which may not be valid. The transmissivity estimate from 

the hydraulic test, however, is lower than would be expected 

based on the relatively high specific capacity of the test well 

(table 1), indicating that the shallowest zone may have been 

sealed during this test. 

The logs of hydraulic-head differences estimated by 

the flow-log method and those measured in the monitoring 

installations are significantly correlated (fig. 7). The fitted 

relation is

log HDMM = 0.19 + 0.68 log HDFL , (2)

where

HDMM is hydraulic-head difference measured 

between monitoring-well intervals, in feet;

and

HDFL is hydraulic-head difference between flow 

zones estimated from flow-log method, 

in feet.

Discrepancies between the hydraulic-head differences 

are, in part, due to difficulties in matching very low flows 

associated with poorly transmissive zones as a result of the 

relative insensitivity of the model head parameter under 

these conditions.

Selected Results of Aquifer and 

Tracer Tests 

An aquifer test and, subsequently, a tracer test were 

conducted by GZA as part of the hydrogeologic site 

characterization. Barvenik and others (2008) present the 

design and analysis of these tests along with the time-series 

data sets of hydraulic heads and tracer concentrations. 

Selected results of the aquifer and tracer tests are 

presented in this report as corroborating information on 
Selected Results of Aquifer and Tracer Tests 7

1,000

100

10

1

0.1

0.1 1 10 100 1,000

TRANSMISSIVITY,

IN FEET SQUARED PER DAY

FLOW-LOG TRANSMISSIVITY,

IN FEET SQUARED PER DAY

Figure 6. Relation between transmissivity of flow zones penetrated by selected test wells 

estimated from flow-log analysis and measured by hydraulic tests. Red and green diamonds 

indicate selected results for test wells MW-40 and MW-54, respectively.

flow-zone transmissivity and connectivity in support of the 

flow-log analysis. 

The aquifer test was conducted from October 31 to 

November 6, 2006, and involved constant-rate pumping of 

well RW-1 (figs. 2 and 3) at 4 gal/min for 3 days followed 

by 3 days of recovery. Water levels were measured during 

pumping and recovery in monitoring intervals at surrounding 

monitoring-well installations. Maximum observed drawdown 

in selected monitoring-well intervals divided by the log of 

the horizontal distance between the pumped well and the 

monitoring well is presented in appendix 1. 

The tracer test involved the introduction of fluorescein 

dye on February 8, 2007, through gravity-fed injection of a 

dye and water mixture into the unsaturated zone at the top 

of bedrock near monitoring-well installation MW-30 (figs. 2 

and 3). Tracer sampling from monitoring intervals at well 

installations commenced prior to and continued following 

injection for 7 months. Peak concentration of the tracer and 

travel velocities for first and peak arrivals, which are defined 

in this report as the travel times divided by the horizontal 

distance between the injection point and the monitoring 

well, are presented for selected monitoring-well intervals in 

appendix 1. 
8 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York

Table 1. Construction and hydrologic information for selected test wells, Indian Point Energy Center site, Buchanan, New York.

[USGS well ID, test-well identification number assigned by U.S. Geological Survey (“We” indicates Westchester County); site well ID, test-well identification 

number assigned by site owner (RW, recovery well; MW, monitoring well); altitude, altitude of land surface, in feet above National Geodetic Vertical Datum of 

1929; well depth and casing depth in feet below land surface; water-level depth, depth to water level during ambient flow logging, in feet below land surface; 

pumped rate, discharge rate during pumped flow logging, in gallons per minute; drawdown, quasi-steady-state drawdown during pumped flow logging, in feet; 

specific capacity, in gallons per minute per foot of drawdown; --, no data]

USGS 

well ID 

Site 

well ID Altitude Well depth 

Casing 

depth 

Water-level

depth 

Pumped 

rate Drawdown Specific capacity 

We-3472 RW-1 76 134 5 63 0.60 1.93 0.31

We-3473 MW-30 76 84 29 40.5 a -- --

We-3474 MW-31 77 87 5.5 32 .48 b --

We-3475 MW-32 79 196 8 37 .25 0.50 .50

We-3476 MW-34 19 30 5 8.3 .48 c --

We-3477 MW-35 19 30 7.5 8.7 .45 d --

We-3478 MW-39 82 199 23 54 .45 .49 .92

We-3479 MW-40 75 192 7 15 .5 .15 3.33

We-3480 MW-46 17 32 6 7 .42 2.10 .20

We-3481 MW-51 70 200 20.5 28 .75 4.58 .16

We-3482 MW-52 17 197 13 12 -- d --

We-3483 MW-53 70 124 30 58 .44 3.75 .12

We-3484 MW-54 15 205 20.5 7 .77 1.28 .60

We-3485 MW-55 18 77 12 10 .71 .97 .73

We-3486 MW-56 70 87 30.5 47.5 .43 .92 .47

We-3487 MW-57 15 31 6 5.3 .41 .34 1.21

We-3488 MW-58 15 71 14 6 .60 2.35 .26

We-3489 MW-59 15 77 18 13 .67 .40 1.68

We-3490 MW-60 14 202 8.5 10 .52 3.75 .14

We-3491 MW-62 15 200 40.5 11.5 .43 3.94 .11

We-3492 MW-63 14 193 36 12.5 .58 .05 11.6

We-3493 MW-65 70 82 34 35.5 .15 3.95 .04

We-3494 MW-66 14 200 37.5 13 .54 .55 .98

We-3495 MW-67 15 340 32.5 13.5 .54 .52 1.04

a

Not pumped because water was added previously for acoustic-televiewer logging.

b

Zero drawdown reported; drawdown assumed to be 0.25 feet for flow-log analysis. 

c

Drawdown not measured.

d

Water level dropped rapidly and pumped rate was not sustained.
Summary 9

Summary 

Flow logs from selected test wells at the Indian Point 

Energy Center in Buchanan, New York, were analyzed as part 

of the hydraulic characterization of the metamorphosed and 

fractured carbonate bedrock underlying the site. The flow 

logs collected under ambient and quasi-steady-state pumped 

conditions were analyzed along with caliper, optical- and 

acoustic-televiewer, fluid-resistivity, and temperature logs to 

determine the character and distribution of flow zones. Many 

flow zones were associated with subhorizontal to shallowdipping fractured zones, southeast-dipping bedding fractures, 

northwest-dipping orthogonal fractures, or combinations of 

bedding and orthogonal fractures. The transmissivity and 

hydraulic head of the flow zones were estimated by matching 

measured and modeled ambient and pumped flows. Flow-log 

analysis generally provided reasonable first-order estimates 

of flow-zone transmissivity and head differences compared 

with the results of conventional hydraulic-test analysis and 

measurements. Selected results of an aquifer test and a tracer 

test provided corroborating information in support of the flowlog analysis.

100

10

1

0.1

0.1 1 10 100

HEAD DIFFERENCE, IN FEET

FLOW-LOG HEAD DIFFERENCE, IN FEET

Figure 7. Relation between hydraulic-head difference of flow zones penetrated by selected 

test wells estimated from flow-log analysis and measured in monitoring-well intervals.
10 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York

References Cited

Barvenik, M.J., Winslow, D.M., Powers, M., and Gozdor, M., 

2008, Hydrogeologic site investigation report, Indian Point 

Energy Center, Buchanan, New York: Report prepared by 

GZA GeoEnvironmental, Inc., Norword, Massachusetts, for 

Enercon Services, Buchanan, New York, 150 p., 18 app. 

Bennett, G.D., Kontis, A.L., and Larson, S.P., 1982, 

Representation of multiaquifer-well effects in threedimensional ground-water flow simulation: Ground Water, 

v. 20, no. 3, p. 334–341.

Dames and Moore, 1975, Supplemental geological 

investigation of the Indian Point Generation Station: Report 

prepared by Dames & Moore, Cranford, New Jersey, for 

Consolidated Edison of New York, Inc., 2 app.

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.

Hvorslev, M.J., 1951, Time lag and soil permeability in 

ground-water observations: Bulletin No. 36, Waterways 

Experimental Station Corps of Engineers, U.S. Army, 

Vicksburg, Mississippi, p. 1–50.

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.

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., 2004, Borehole flowmeter applications in 

irregular and large diameter boreholes: Journal of Applied 

Geophysics, v. 55, no. 1–2, p. 39–59.

Ratcliffe, N.M., Bender, J.F., and Tracy, R.J., 1983, 

Tectonic setting, chemical petrology and petrogenesis 

of the Cortlandt Complex and related igneous rocks of 

southeastern New York: Field Guide for Northeastern 

Section Geological Society Meeting, Kiamesha Lake, New 

York, March 23–26, 1983.

Theis, C.V., 1935, The relation between the lowering of 

the piezometric surface and the rate and duration of 

discharge of a well using groundwater storage: American 

Geophysical Union Transactions, v. 16, p. 519–524.

Williams, J.H., and Johnson, C.D., 2000, Borehole-wall 

imaging with acoustic and optical televiewers for fracturedbedrock aquifer investigations, in Proceedings of the 7th 

Minerals and Geotechnical Logging Symposium, October 

24–26, 2000, Golden, Colorado: Minerals and Geotechnical 

Logging Society, p. 43–53.
Appendix 1 11

Appendix 1. Composites of Geophysical Logs, Transmissivity and HydraulicHead Difference Estimates and Measurements, and Selected Aquifer- and 

Tracer-Test Results for the Test Wells, Indian Point Energy Center Site, 

Buchanan, New York. 

Explanation

MW-30 Site well identifier

Depth Depth, in feet below land surface 

Caliper Caliper collected by Geophysical Applications, Inc. (GAI); borehole diameter in inches 

OTV Optical televiewer collected by GAI; 360-degree optical image of borehole wall oriented to True 

Geographic North

ATV Acoustic televiewer collected by GAI; 360-degree acoustic image of borehole wall oriented to True 

Geographic North

Stereo Lower-hemisphere, Schmidt stereo plot of planar fracture and bedding features oriented to True Geographic 

North; gray disk indicates features picked by GAI; blue box indicates hydraulically active fracture based on 

USGS flow-log analysis

Tadpole Tadpole plot of planar fracture and bedding features oriented to True Geographic North; body of tadpole 

indicates dip angle and tail indicates dip direction; gray disk indicates features picked by GAI; blue box 

indicates hydraulically active fracture based on USGS flow-log analysis

Amb Flow Ambient flow, in gallons per minute; blue disk indicates flow measurement collected by GAI with heat-pulse 

flowmeter at specified depth; blue line indicates modeled flow based on USGS analysis 

Pmp Flow Pumped flow, in gallons per minute; red circle indicates flow measurement collected by GAI with heat-pulse 

flowmeter at specified depth; red line indicates modeled flow based on USGS flow-log analysis 

Fl Res Fluid resistivity collected by GAI, in ohms per meter

Fl Temp Temperature collected by GAI, in degrees Celsius

Trans Transmissivity of straddle-packed or monitored-well interval as reported by Barvenik and others (2008), in 

feet squared per day 

FL Trans Transmissivity of flow zone based on USGS flow-log analysis, in feet squared per day 

Head Diff Hydraulic-head difference between monitored-well intervals as reported by Winslow and others (2008), in

FL Head Diff Hydraulic-head difference between flow zones based on USGS flow-log analysis, in feet

Drawdown Maximum observed drawdown divided by log distance between the monitoring well and the pumped well 

(RW-1), in feet divided by log feet; ND indicates no observed drawdown

Open Zone Open zone of monitoring-well installation

First TT Travel velocity of first arrival of tracer, in feet per day

Peak TT Travel velocity of peak arrival of tracer, in feet per day

Peak Conc Peak concentration of tracer, in micrograms per liter; ND indicates non-detect
12 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York Depth

1ft:75ft

MW-30

Fl Res

0 Ohm-m

Caliper

3.75 In

Amb Flow

0.4 -0.4 Gal/Min

ATV Tadpole Stereo

90 0

Trans

20 0.002 Ft^2/D

Fl Temp 

20 Deg C

Drawdown

0 Ft/Log Ft

Open Zone

0 Ft/D

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L

3035404550556065707580

0°

180°

60

23

15

First TT

50000

10

10

3.85
Appendix 1 13

Depth

1ft:120ft

MW-31

Caliper

3.6 In

Trans

500 0.5 Ft^2/D

OTV ATV Tadpole

90 0

Stereo

FL Trans

500 0.5 Ft^2/D

Fl Res 

2.5 Ohm-m

Fl Temp 

19 Deg C

Amb Flow

0.6 -0.6 Gal/Min

Pmp Flow

0.6 -0.6 Gal/Min

Open Zone

0 Ft/D

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L

Drawdown

0 Ft/Log Ft

Head Diff

3 0 Ft

FL Head Diff

3 0 Ft

1020304050607080

0°

180°

4.1 4.5

21

First TT

100

100

50000

1
14 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York Depth 1ft:260ft MW-32 Fl Res 10 Ohm-m Caliper 3.5 In OTV ATV 90 0 Trans 400 0.4 Ft^2/D Amb Flow 0.6 -0.6 Gal/Min FL Trans 400 0.4 Ft^2/D Head Diff 35 0 Ft Pmp Flow 0.6 -0.6 Gal/Min Fl Temp 16 Deg C FL Head Diff 35 0 Ft Open Zone

0 Ft/D

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L

20406080

100120140160180

200

0°

180°

4.5

Tadpole Stereo

20

23

First TT

50000

100

100
Appendix 1 15

Depth

1ft:40ft

MW-34

Fl Res 

18 Ohm-m

Caliper

3.5 In

Amb Flow 

0.1 -0.1 Gal/Min

Pmp Flow

0.1 -0.1 Gal/Min

Tadpole

90 0

Stereo Trans

100 0.1 Ft^2/D

ATV

Fl Temp

8 Deg C

Open Zone Drawdown

0 Ft/Log Ft

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L

 5

10152025

0°

180°

4.5 22

18

1

50000

10
16 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York Depth 1ft:40ft MW-35 Fl Res 15 Ohm-m Caliper 3.5 In Amb Flow 0.2 -0.2 Gal/Min Pmp Flow 0.2 -0.2 Gal/Min ATV Tadpole 90 0 Stereo Trans 100 0.1 Ft^2/D Fl Temp

8 Deg C

Open Zone Drawdown

0 Ft/ Log Ft

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L

 5

10152025

30

0°

180°

4 18

19

1 10

50000
Appendix 1 17

Depth

1ft:230ft

MW-39

Fl Res 

0.5 Ohm-m

Caliper

3.7 In

ATV

90 0

Amb Flow

0.5 -0.5 Gal/Min

Trans

200 0.02 Ft^2/D

Pmp Flow

0.5 -0.5 Gal/Min

Fl Temp 

15.2 Deg C

FL Trans

200 0.02 Ft^2/D

Open Zone Head Diff

2 -2 Ft

FL Head Diff

2 -2 Ft

Drawdown

0 Ft/Log Ft

Peak Conc

0.05 ug/L

20406080

100120140160180

200

0°

180°

ND

NDNDNDNDNDND

4.1

Tadpole Stereo

16.2

4.5 1 50000
18 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York Depth 1ft:250ft MW-40 Fl Res 

-5 -3 Ohm-m

Caliper

3.5 In

ATV Tadpole

90 0

Stereo Trans

0001 1. 0 Ft^2/D

Amb Flow 

0.6 -0.6 Gal/Min

FL Trans

0001 1. 0 Ft^2/D

Pmp Flow 

0.6 -0.6 Gal/Min

Fl Temp

12 Deg C

Open Zone Head Diff

8 8- Ft

FL Head Diff

8 8- Ft 0

20406080

100120140160180

200

0°

180°

5

16.5
Appendix 1 19

Depth

1ft:40ft

MW-46

Fl Res

-25 5 Ohm-m

Caliper

3.5 In

Tadpole

90 0

Stereo

Fl Temp

10 Deg C

ATV FL Trans

50 0.5 Ft^2/D

FL Head Diff

1 0 Ft

Amb Flow

0.6 -0.6 Gal/Min

Pmp Flow

0.6 -0.6 Gal/Min

Drawdown

0 Ft/Log Ft

Open Zone

0.05 ug/L

 5

1015202530

0°

180°

DN DN

5

23

1

Peak Conc

50000
20 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York Depth 1ft:230ft MW-51 Fl Res -3.5 1 Ohm-m Caliper 3.5 In ATV Tadpole 90 0 Stereo Trans 20 0.2 Ft^2/D Fl Temp 12 Deg C Pmp Flow 0.8 -0.8 Gal/Min Amb Flow 0.8 -0.8 Gal/Min FL Trans 20 0.2 Ft^2/D Open Zone Drawdown

0 Ft/Log Ft

Peak Conc

0.05 ug/L

Head

25 0 Ft

FL Head Diff

25 0 Ft

20406080

100120140160180

200

0°

180°

DN DN

4.5

14.5

1 50000
Appendix 1 21

MW-52

Ohm-m

20406080

100120140160180

0°

180°

NDND

NDNDNDNDND

Depth

1ft:235ft

Fl Res Caliper

3 In

Tadpole

90 0

ATV Stereo Trans

7 0.007 Ft^2/D

Amb Flow

0.2 -0.2 Gal/Min

Fl Temp

12 Deg C

Pmp Flow

0.2 -0.2 Gal/Min

Open Zone

0 Ft/D

Peak Conc

0.05 ug/L

Drawdown

0 Ft/Log Ft

Head

8 0 Ft 5

19

Peak TT

50000

10 1
22 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York Depth 1ft:125ft MW-53 Fl Res -22 -12 Ohm-m Caliper 3.5 In Tadpole 90 0 ATV Stereo Trans 200 2 Ft^2/D FL Trans 200 2 Ft^2/D Amb Flow 0.5 -0.5 Gal/Min Fl Temp 17.5 Deg C Pmp Flow 0.5 -0.5 Gal/Min Open Zone

0 Ft/D

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L

Drawdown

0 Ft/Log Ft

Head Diff

2 0 Ft

FL Head Diff

2 0 Ft

30405060708090

100110120

0°

180°

ND

4.5

20

First TT

50000

100

100

1
Appendix 1 23

6.7 3 In 90 0 40 0.4 0.7 -0.7

40 0.4 0.7 -0.7 14.6

4 0 04 0

000.05

5 8.3

24.2

1 100

100

50000

Depth

1ft:250ft

MW-54

Fl Res 

Ohm-m

Caliper Tadpole OTV ATV Stereo Trans

Ft^2/D

Amb Flow

Gal/Min

FL Trans

Ft^2/D

Pmp Flow

Gal/Min

Fl Temp

Deg C

FL Head Diff

Ft

Open Zone Drawdown

Ft/Log Ft

Head Diff

Ft

First TT

Ft/D

Peak TT

Ft/D

Peak Conc

ug/L

20406080

100120140160180200

0°

180°

ND
24 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York Depth 1ft:90ft MW-55 Caliper 3.5 In Tadpoles 90 0 ATV OTV Stereo Trans 300 0.3 Ft^2/D FLTrans 300 0.3 Ft^2/D Fl Res

6 Ohm-m

Amb Flow 

0.8 -0.8 Gal/Min

Fl Temp

17.6 Deg C

Pmp Flow

0.8 -0.8 Gal/Min

Head Diff

1 -1 Ft

FL Head Diff

1 -1 Ft 

Open Zone

0 Ft/D

Drawdown

0 Ft/Log Ft

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L

15202530354045505560657075

0°

180°

4.5 11

22.6

1

First TT

1010

50000
Appendix 1 25

Depth

1ft:75ft

MW-56

Fl Res 

6 Ohm-m

Caliper

3.5 In

Tadpole

90 0

OTV ATV Stereo Trans

200 0.2 Ft^2/D

FL Trans

200 0.2 Ft^2/D

Amb Flow

0.5 -0.5 Gal/Min

Fl Temp

15 Deg C

Pmp Flow

0.5 -0.5 Gal/Min

Open Zone Head Diff

2 0 Ft

FL Head Diff

2 0 Ft

Drawdown

0 Ft/Log Ft

303540455055606570758085

0°

180°

ND

4.5 8

20

1
26 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York Depth 1ft:55ft MW-57 Fl Res 6.5 Ohm-m Caliper 3.5 In Tadpole 90 0 ATV Stereo Trans 300 0.3 Ft^2/D Amb Flow 0.5 -0.5 Gal/Min Head Diff .5 1 0 Ft Fl Temp 19 Deg C FL Trans 300 0.3 Ft^2/D Pmp Flow 0.5 -0.5 Gal/Min FL Head Diff 1.5 0 Ft Drawdown

0 Ft/Log Ft

Open Zone

0 Ft/D

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L

1015202530354045

0°

180°

NDNDND

NDND

4.5 7.5

24

1

First TT

100

100

50000
Appendix 1 27

Depth

1ft:75ft

MW-58

Fl Res 

6 Ohm-m

Caliper

3.6 In

Tadpole

90 0

ATV Trans

100 1 Ft^2/D

Stereo

FL Trans

100 1 Ft^2/D

Amb Flow

0.6 -0.6 Gal/Min

Head Diff

1 0 Ft

FL Head Diff

1 0 Ft

Fl Temp

16.75 Deg C

Pmp Flow

0.6 -0.6 Gal/Min

Drawdown

0 Ft/Log Ft

Open Zone

0 Ft/D

Peak Conc

0.05 ug/L

1520253035404550556065

70

0°

180°

NDND

4 14

18.75

1

Peak TT

50000

100
28 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York Depth 1ft:90ft MW-59 Fl Res 

2 Ohm-m

Caliper

3.5 In

Tadpole

90 0

OTV ATV Stereo Trans

300 0.3 Ft^2/D

FL Trans

300 0.3 Ft^2/D

Amb Flow

1 -1 Gal/Min

Head Diff

2 0 Ft

FL Head Diff

2 0 Ft

Fl Temp

18 Deg C

Pmp Flow

1 -1 Gal/Min

Drawdown

0 Ft/Log Ft

Open Zone

0 Ft/D

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L

15202530354045505560657075

0°

180°

NDNDND

NDND

4.5 13

25.5

1

First TT

10

10

50000
Appendix 1 29

Depth

1ft:275ft

MW-60

Amb Flow

0.6 -0.6 Gal/Min

Fl Res 

4 Ohm-m

Caliper

3.5 In

Tadpole

90 0

OTV ATV Stereo Trans

20 0.02 Ft^2/D

FL Trans

20 0.02 Ft^2/D

Pmp Flow

0.6 -0.6 Gal/Min

Fl Temp 

12.6 Deg C

Drawdown

0 Ft/Log Ft

Open Zone Head Diff

3 0 Ft

FL Head Diff

3 0 Ft

First TT

0 Ft/D

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L 0

20406080

100120140160180200

0°

180°

ND

NDNDNDNDND

4.5 15

20.4

1 10

10

50000
30 Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at Indian Point Energy Center, Buchanan, New York Depth 1ft:210ft MW-62 Amb Flow 0.6 -0.6 Gal/Min Fl Res 10 Ohm-m Caliper 3.5 In Tadpole 90 0 ATV OTV Trans 30 0.03 Ft^2/D Stereo Pmp Flow 0.6 -0.6 Gal/Min FL Trans 30 0.03 Ft^2/D Fl Temp 13.8 Deg C Drawdown

0 Ft/Log Ft

Open Zone Head Diff

1 0 Ft

FL Head Diff

1 0 Ft

First TT

0 Ft/D

Peak TT

0 Ft/D

Peak Conc

0.05 ug/L

406080

100120140160180

200

0°

180°

ND

NDNDND

7 25

16.1

1

50000

10

10
For additional information write to: 

New York Water Science Center

U.S. Geological Survey

425 Jordan Road 

Troy, NY 12180

Information requests:

(518) 285-5602

or visit our Web site at:

http://ny.water.usgs.gov
Williams, J.H.—Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at the Indian Point Energy Center, Buchanan, New York—Open-File Report 2008–1123