76°30' 76°25'

42°25'

42°20'

City of Ithaca

Village 

of Cayuga 

Heights

Town of Ithaca

Town of Town of Danby

Newfield

Village of Lansing Town 

of Lansing

Town of Dryden

Town of 

Caroline

Town of Ulysses

TIOGA COUNTY

TOMPKINS COUNTY

Lower Sixmile Creek and

Willseyville Creek trough

valley

Northern areastratified-drift 

aquifer 

Central areastratified-drift

 aquifer 

Southern area-

 stratified-drift

 aquifer 

Prepared in cooperation with the Town of Caroline and the

Tompkins County Planning Department

Geohydrology of the Stratified-Drift Aquifer System in 

the Lower Sixmile Creek and Willseyville Creek Trough, 

Tompkins County, New York

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2010–5230
Front Cover. Figure 4 inside report.
Geohydrology of the Stratified-Drift Aquifer 

System in the Lower Sixmile Creek and 

Willseyville Creek Trough, Tompkins 

County, New York

By Todd S. Miller and Daniel E. Karig

Prepared in cooperation with the Town of Caroline and 

the Tompkins County Planning Department

Scientific Investigations Report 2010– 5230

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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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:

Miller, T.S. and Karig, D.E., 2010, Geohydrology of the stratified-drift aquifer system in the lower Sixmile Creek 

and Willseyville Creek trough, Tompkins County, New York: U.S. Geological Survey Scientific Investigations Report 

2010–5230, 54 p. (Also available at http://pubs.usgs.gov/sir/2010–5230.)
iii

Contents

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

Introduction.....................................................................................................................................................2

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

Description of Study Area ...................................................................................................................5

Previous Studies ...................................................................................................................................7

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

Geologic Data........................................................................................................................................7

Seismic Surveys....................................................................................................................................7

Well Inventory, Test Drilling, and Water-Level Measurements ....................................................7

Water Sampling and Analysis.............................................................................................................8

Geology ...........................................................................................................................................................8

Glacial History .......................................................................................................................................8

Scouring by Ice ...................................................................................................................................12

Wisconsinan Deposits in the Study Area .......................................................................................12

Southern Part of Study Area ...................................................................................................14

Central Part of the Study Area.................................................................................................14

Northern Part of the Study Area .............................................................................................17

Hydrology of the Stratified-Drift Aquifer System....................................................................................18

Aquifer Types.......................................................................................................................................25

Aquifer Geometry................................................................................................................................25

Unconfined Headwater Aquifer ..............................................................................................25

Unconfined Deltaic Aquifer......................................................................................................25

Confined and Locally Unconfined Aquifers ..........................................................................26

Bedrock Aquifers.......................................................................................................................28

Groundwater Levels and Flowpaths................................................................................................28

Sources of Recharge ........................................................................................................................32

Unconfined Aquifers .................................................................................................................32

Confined Aquifers ......................................................................................................................33

Groundwater Discharge ...................................................................................................................33

Unconfined Aquifer at the Brooktondale Delta ....................................................................33

Confined Aquifers ......................................................................................................................33

Pumping Withdrawals...............................................................................................................38

Groundwater Quality ...................................................................................................................................39

Physical Properties.............................................................................................................................39

Major Inorganic Ions..........................................................................................................................39

Nutrients...............................................................................................................................................39

Trace Elements....................................................................................................................................39

Comparison to Other Stratified-Drift Aquifers in Tompkins County............................................43

Summary........................................................................................................................................................43

Selected References...................................................................................................................................45

Appendix 1. Records of selected wells in lower Sixmile Creek and Willseyville Creek trough, 

Tompkins and Tioga Counties, New York............................................................................................47
iv

Figures

1. Map showing location of 17 stratified-drift aquifer reaches in Tompkins

County, New York..........................................................................................................................3

2. Map showing physiographic features and location of the lower Sixmile Creek and

Willseyville Creek trough study area, Tompkins County, New York .....................................4

3. Map showing location of stratified-drift aquifers extending across the lower

Sixmile Creek and Willseyville Creek Basins and across the upper Sixmile Creek

and West Branch Owego Creek Basins, Tompkins County, New York ................................5

4. Map showing shaded relief and location of stratified-drift aquifers in the lower

Sixmile Creek and Willseyville Creek trough in Tompkins County, New York.....................6

5. Map showing surficial geology of the lower Sixmile Creek and Willseyville Creek

trough, Tompkins County, New York ........................................................................................10

6. Map showing bedrock structure map of lower Sixmile Creek and Willseyville 

Creek trough Tompkins County, New York..............................................................................13

7. Diagram showing geohydrologic section A–A’ showing results of

horizontal-to-vertical (H/V) ambient-noise and seismic-refraction surveys along

Ridgeway Road, Town of Caroline, New York ........................................................................15

8. Diagram showing geohydrologic section B—B’ in the lower Sixmile Creek and

Willseyville Creek trough, Town of Caroline, New York .......................................................16

9. Diagram showing geohydrologic section C—C’ in the lower Sixmile Creek and

Willseyville Creek trough, Town of Caroline, New York .......................................................17

10. Diagram showing geohydrologic section D—D’ in the lower Sixmile Creek and

Willseyville Creek trough, Tompkins County, New York .......................................................19

11. Map showing geohydrologic section E—E’ in the lower Sixmile Creek and

Willseyville Creek trough, Tompkins County, New York .......................................................20

12. Diagram showing geohydrologic section F—F’ of glacial and fluvial systems in 

the Sixmile Creek and Willseyville Creek trough, Towns of Caroline, Dryden, and 

Ithaca, New York.........................................................................................................................21

13. Map showing location of wells in lower Sixmile Creek valley and Willseyville 

Creek trough, Tompkins County, New York.............................................................................22

14. Map showing aquifer types in lower Sixmile Creek and Willseyville Creek trough,

Tompkins County, New York......................................................................................................23

15. Diagram showing well log and construction details of USGS test wells TM1008 

and TM1009, Perkins Road, Town of Caroline, New York.....................................................26

16. Map showing water table in the unconfined aquifer (Brooktondale Delta) in lower

Sixmile Creek and Willseyville Creek trough, Tompkins County, New York......................28

17. Map showing potentiometric surface in the upper confined aquifer in lower 

Sixmile Creek and Willseyville Creek trough, Tompkins County, New York......................30

18. Map showing potentiometric surface in the basal confined aquifer in lower 

Sixmile Creek and Willseyville Creek trough, Tompkins County, New York......................34

 19. Hydrograph showing altitude of groundwater levels from January 1, 2007 to 

February 11, 2009 in test wells TM1008 and TM1009 at Town of Caroline sand 

and gravel pit, Perkins Road, Brooktondale, New York........................................................36

20. Diagram showing sources of recharge in aquifers A, the northern part of the 

lower Sixmile Creek and Willseyville Creek trough, B, the central part, and 

C, the southern part Tompkins County, New York. ................................................................37
v

21. Graphs showing results of hydrograph separation analyses for Sixmile Creek at 

Brooktondale (upper Sixmile Creek Basin) and Sixmile Creek at Bethel Grove 

streamgages (lower Sixmile Creek Basin) for the period 2002–07.....................................38

22. Piper diagram illustrating variability in major ion composition of groundwater in 

lower Sixmile Creek and Willseyville Creek trough, upper Sixmile Creek and West 

Branch Owego Creek valleys, Virgil Creek valley, and upper Buttermilk and Danby 

Creek valleys, Tompkins County, New York............................................................................44

Tables

1. Time-stratigraphic classification of Pleistocene stades and interstades in

northeastern North America.......................................................................................................9

2. Physical properties, concentrations of major inorganic ions, and concentratins of

nutrients in groundwater samples from confined aquifers in the lower Sixmile

Creek and Willseyville Creek trough, Tompkins County, New York, 2006-2007 ...............40

3. Concentrations of trace metals in groundwater samples from confined aquifers in

the lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York,

2006–2007 ....................................................................................................................................42

Conversion Factors, Datum, and Abbreviations

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2) 2.590 square kilometer (km2) 

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

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

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

°F= (1.8×°C) +32

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

°C= (°F-32)/1.8

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

(NAVD 88).

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

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

List of Abbreviations

GWSI Groundwater site inventory

H/V Horizontal-to-vertical 

HYSEP Hydrograph-separation computer program 

LIDAR Light detection and ranging

MCL Maximum Contaminant Level 

NWIS National Water Information System 

NWQL National Water Quality Laboratory

NYSDOH New York State Department of Health

SMCL Secondary Maximum Contaminant Level 

TM Tompkins

USEPA U.S. Environmental Protection Agency 

USGS U.S. Geological Survey
Geohydrology of the Stratified-Drift Aquifer System in 

the Lower Sixmile Creek and Willseyville Creek Trough, 

Tompkins County, New York

By Todd S. Miller and Daniel E. Karig1

Abstract

In 2002, the U.S. Geological Survey, in cooperation with 

the Tompkins County Planning Department began a series of 

studies of the stratified-drift aquifers in Tompkins County to 

provide geohydrologic data for planners to develop a strategy 

to manage and protect their water resources. This aquifer 

study in lower Sixmile Creek and Willseyville Creek trough is 

the second in a series of aquifer studies in Tompkins County. 

The study area is within the northern area of the Appalachian 

Plateau and extends about 9 miles from the boundary between 

Tompkins County and Tioga County in the south to just south 

of the City of Ithaca in the north. In lower Sixmile Creek and 

Willseyville Creek trough, confined sand and gravel aquifers 

comprise the major water-bearing units while less extensive 

unconfined units form minor aquifers. 

About 600 people who live in lower Sixmile Creek 

and Willseyville Creek trough rely on groundwater from 

the stratified-drift aquifer system. In addition, water is used 

by non-permanent residents such as staff at commercial 

facilities. The estimated total groundwater withdrawn for 

domestic use is about 45,000 gallons per day (gal/d) or 

0.07 cubic foot per second (ft3

/s) based on an average water 

use of 75 gal/d per person for self-supplied water systems in 

New York.

Scouring of bedrock in the preglacial lower Sixmile 

Creek and Willseyville Creek valleys by glaciers and 

subglacial meltwaters truncated hillside spurs, formed 

U-shaped, transverse valley profiles, smoothed valley walls, 

and deepened the valleys by as much as 300 feet (ft), forming 

a continuous trough. The unconsolidated deposits in the study 

area consist mostly of glacial drift, both unstratified drift (till) 

and stratified drift (laminated lake, deltaic, and glaciofluvial 

sediments), as well as some post-glacial stratified sediments 

(lake-bottom sediments that were deposited in reservoirs, 

1

Daniel E. Karig, Cornell University, Ithaca, NY

peat and muck that were deposited in wetlands, and alluvium 

deposited by streams). Multiple advances and retreats of the 

ice in the study area resulted in several sequences of various 

types of glacial deposits. A large moraine (Valley Heads 

Moraine) dominates the southern part of the study area, a 

large delta dominates the central part, and ground moraine 

(mostly till) dominates the northern part. Glacial sediments in 

the center of the lower Sixmile Creek and Willseyville Creek 

trough typically range from 150 to 200 ft but can be greater 

than 300 ft in some places. Where the sediments are composed 

of sand and gravel they form aquifers. 

In most parts of the lower Sixmile Creek and Willseyville 

Creek trough, there is an upper and a basal confined aquifer. 

However, underlying the central parts of the Brooktondale 

delta, there are as many as four confined aquifers, whereas in 

the northern part of the study area, only one extensive confined 

aquifer is present. The major sources of recharge to these 

confined aquifers are (1) direct infiltration of precipitation 

where confined aquifers crop out at land surface (mostly along 

the western trough wall in the southern and central parts of 

the study area and, to a lesser degree, along the eastern trough 

wall); (2) unchanneled surface and subsurface runoff from 

adjacent upland areas that seeps into the aquifer along the 

western trough walls; (3) subsurface flow from underlying till 

or bedrock at the lateral contacts at trough walls; (4) adjacent 

fine-grained stratified drift, especially when the aquifer is 

pumped; and (5) discharge from bedrock at the bottom and 

sides of the trough.

In the central part of the study area, the surficial 

coarse-grained sediments (sand and gravel) comprise a delta 

near Brooktondale and form a small unconfined aquifer 

(0.3 square mile). Although much of the upper part of the delta 

has been removed by several aggregate mining operations, 

sufficient amounts of sand and gravel remain in most places 

to form a thin unconfined aquifer. The major sources of 

recharge to the unconfined aquifer are (1) direct infiltration 

of precipitation where water moves predominantly in a 

downward direction through the unsaturated zone toward the 

water table and (2) unchanneled surface and subsurface runoff 

from adjacent upland areas that seep into the aquifer along the 

trough walls.
2 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

Groundwater in the southern part of the Brooktondale 

delta flows to the west and discharges into Beaver Creek. 

Groundwater in the northern part of the deltaic aquifer flows 

to the northwest where some of the groundwater discharges to 

springs along the northeastern margin of the delta and flows 

into lower Sixmile Creek and some groundwater discharges 

to springs along the northwestern margin of the delta and 

flows into Beaver Creek. Just north of the surface-water 

divide in the southern part of the study area groundwater in 

the confined aquifers on the west side of the trough initially 

flows eastward from the west valley wall to the center of the 

valley where it then changes course and flows northward. In 

the northern part of the central area of the trough, the upper 

confined aquifer either pinches out at depth or has been eroded 

by Sixmile Creek and is exposed beneath the floodplain where 

groundwater discharges directly into Sixmile Creek. In the 

northern part of the study area, groundwater in the confined 

aquifer ultimately discharges into Sixmile Creek and to the 

Ithaca Reservoir.

An initial assessment of the groundwater quality of 

the confined aquifer system near the central portion of the 

study area, where most of the wells are located, was made by 

collecting water samples from six wells (two test wells and 

four residential wells) from December 2006 through August 

2007 and analyzing the samples to characterize the quality of 

groundwater. Common ions, nutrients, and trace metals were 

sampled and field properties of pH, specific conductance, and 

temperature were measured. All common ions were below 

U.S. Environmental Protection Agency Drinking Water 

Advisory limits. These results indicate that water in the sand 

and gravel aquifers is predominantly calcium-bicarbonate, 

and groundwater used for drinking supply is generally of 

acceptable quality.

Nitrate was not detected in any of the samples above 

the detection limit of 0.06 mg/L (milligram per liter). Nitrite 

was not detected in five of the six samples and was negligible 

(0.001 mg/L) in the sixth sample. The most commonly 

detected trace elements were aluminum, arsenic, barium, 

boron, iron, lithium, manganese, nickel, and strontium, 

all of which were detected in every sample. The elements 

detected in the highest concentrations were barium, boron, 

iron, lithium, manganese, strontium, and uranium. Aluminum 

concentrations ranged from 0.9 to 95.5 micrograms per 

liter (μg/L); one sample exceeded the Secondary Maximum 

Contaminant Level of 50 μg/L. Arsenic concentrations ranged 

from 1.3 to 20.4 μg/L; two samples exceeded the Federal 

Maximum Contaminant Level for arsenic of 10 μg/L. 

Introduction

In 2002, the U.S. Geological Survey (USGS), in 

cooperation with the Tompkins County Planning Department 

began a series of studies of the stratified-drift aquifers in 

Tompkins County to provide geohydrologic data for planners 

to develop a strategy to manage and protect their water 

resources. A reconnaissance-level USGS aquifer map report 

“Unconsolidated Aquifers in Tompkins County, New York” 

(Miller, 2000) was used as a guide to delineate 17 reaches 

of stratified-drift aquifers (fig. 1) to be investigated in more 

detail over a 20-year period. The aquifer reaches were 

based mostly on natural hydrologic boundaries, but in some 

cases political boundaries were also considered. Aquifer 

reach lengths were limited to about 3 to 10 miles each to be 

logistically manageable. 

Tompkins County lies within the northern area of the 

Appalachian Uplands in central New York (fig. 2). The 

northern part of the county is within the glacially eroded 

Finger Lakes region with rounded hills of low-to-moderate 

relief, whereas the southern part of the county lies within the 

Appalachian Plateau region of moderately high relief (fig. 2). 

The stratified-drift aquifers in the lower Sixmile Creek and 

Willseyville Creek trough, described in this report, lie within 

the moderately high relief portion of the Appalachian Plateau 

region (fig. 2).

The geologic history of Sixmile Creek Basin, discussed 

in detail in the “Geology and Glacial Geology” section in 

a report by Miller (2009), has resulted in the creation of 

two distinct hydrophysiographic settings, which allowed 

the division of Sixmile Creek valley into two study areas—

upper Sixmile Creek valley, including the headwaters of 

West Branch Owego Creek valley (Miller, 2009), and 

lower Sixmile Creek valley, including the headwaters of 

Willseyville Creek valley (fig. 3) (this study). In the upper 

Sixmile Creek and West Branch Owego Creek valleys study 

area (1) upper Sixmile Creek and East Branch Owego Creek 

valleys are higher in altitude, (2) the valleys were oriented 

perpendicular to the predominantly north to south flow of 

glacial ice undergoing less erosion by ice, which resulted 

in a hanging valley, and (3) the valleys were dominated by 

depositional environments that included subglacial (deposition 

of till), glaciofluvial, glaciolacustrine, and post-glacial 

fluvial processes. In contrast, in the lower Sixmile Creek 

and Willseyville Creek trough study area; (1) the valleys are 

lower in altitude; (2) were oriented roughly parallel to the 

direction of glacial ice flow, and therefore, were extensively 

scoured by ice that formed a trough; and (3) were dominated 

by depositional environments that included subglacial, deltaic, 

ice-contact, and glaciolacustrine processes. 

Preglacial valleys that were oriented along the primary 

direction of ice movement, such as those valleys presently 

occupied by Cayuga Lake and lower Sixmile Creek valley 

(fig. 1), were extensively widened and deepened by flowing 

ice and subglacial meltwater. Erosion by ice had truncated 

bedrock hillsides (spurs), which resulted in creation of nearly 

straight, U-shaped bedrock troughs. Bedrock troughs in 

central New York are common along the northern rim of the 

Appalachian Plateau; many of these troughs are in the Finger 

Lakes region. Clayton (1965) referred to the Finger Lakes 

valleys as “intrusive troughs” that were carved when ice that 

flowed south from the Lake Ontario Lowlands encountered 
Introduction 3

Figure 1. Location of 17 stratified-drift aquifer reaches in Tompkins County, New York.

EXPLANATION

Aquifer reach names

Cascadilla Creek valley and upland Sixmile Creek valley

Enfield Creek valley

Lower Cayuga Inlet valley

Lower Fall Creek valley

Lower Sixmile Creek valley (Towns of Dryden and Ithaca)

Owasco Inlet valley

Pony Hollow valley

Salmon Creek/Myers Point/Locke Creek

Taughannock Creek valley and delta

Upper Buttermilk Creek and Danby Creek valleys

Upper Cayuga Inlet valley

Upper Fall Creek valley

Upper Sixmile Creek and West Branch Owego Creek valleys

Virgil Creek valley

West Branch Cayuga Inlet and Fish Kill valleys

West Branch Owego Creek valley and tributaries

Lower Sixmile Creek and Willseyville Creek valleys

(Town of Caroline)

0 2 4 MILES

0 2 4 KILOMETERS

76°40' 76°30' 76°20'

42°30'

42°20'

Aquifers mapped Miller (2000) Basemap created with TOPO!, scale 1:100,000

2003 National Geographic, URL www.nationalgeographic.com/topo

TOWN OF 

LANSING

TOWN OF 

GROTON

TOWN OF 

ULYSSES

TOWN OF 

ENFIELD

TOWN OF 

ITHACA

CITY OF 

ITHACA

TOWN OF 

DRYDEN

TOWN OF 

CAROLINE

TOWN OF 

DANBY

TOWN OF 

NEWFIELD

CAYUGA CO

TOMPKINS CO

TOMPKINS CO

CORTLAND CO

TOMPKINS CO

TIOGA CO

TOMPKINS CO

SCHUYLER CO CHEMUNG CO

TOMPKINS CO

SENECA CO

Study

area
4 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

a landmass of higher altitude, in this case the Appalachian 

Plateau, and flowed uphill, against the regional slope. Bedrock 

troughs are often referred to as having U-shaped profiles 

although many are asymmetrical with one valley wall steeper 

than the other. However, the more valleys and troughs intrude 

southward into the Appalachian Plateau (fig. 2), the more 

widths decrease and the valley profiles transition from broad 

U-shaped, to narrow U-shaped profiles. Since extensive 

scouring by ice of lower Sixmile Creek valley and the 

headwaters of Willseyville Creek valley formed a single deep 

trough, the study area in this report is referred to as the “lower 

Sixmile Creek and Willseyville Creek trough” (throughout this 

report as the “trough”) (fig. 4). 

Purpose and Scope

The Town of Caroline and Tompkins County need 

geohydrologic data regarding the major stratified-drift aquifers 

within the town to develop a strategy to manage and protect 

their water resources. Interest in the interaction between 

groundwater and surface water has increased in recent years 

as a result of widespread concerns related to water supply 

and water quality. This report describes the geohydrology 

of the stratified-drift aquifer system in the lower Sixmile 

Creek and Willseyville Creek trough including (1) the aquifer 

framework; (2) the groundwater-flow system, including 

water levels, groundwater and surface-water interaction, and 

Figure 2. Physiographic features and location of the lower Sixmile Creek and Willseyville Creek trough study area in 

Tompkins County, New York.

Tompkins County

Study Area 

National boundary

State boundary

Physiographic boundary

EXPLANATION

Modified from Cressey, 1966, fig. 9

Mohawk

Lowlands

CANADA

UNITED STATES

CANADA

MILES

KILOMETERS

0 50 100

0 50 100 ATLANTIC OCEAN

Erie 

Lowlands

Appalachian Plateau

(hills of moderate relief)

Appalachian Plateau

(hills of moderate relief)

Finger Lakes and hills of the 

Appalachian Plateau (severly 

eroded low relief)

Study area (in red)

Tompkins

County

NEW YORK

PENNSYLVANNIA

Valley Heads

Moraine

VERMONT

MASSACHUSETTS

NEW 

HAMPSHIRE

CONNECTICUT

Triassic Lowland

Ontario Lowlands

Tug

 Hill

 Plateau

New England Uplands

Hudson 

Lowlandss

St. Lawrence-Champlain Lowlands

Adirondack Mountains

Atlantic Coastal Plain

LAKE ERIE

43o

42o

41o

44o

45o

80o 79o 78o 77o 76o 75o 74o 73o 72o

LAKE ONTARIO

NEW JERSEY
Introduction 5

Figure 3. Location of stratified-drift aquifers extending across the lower Sixmile Creek and Willseyville Creek Basins and across the 

upper Sixmile Creek and West Branch Owego Creek Basins, Tompkins County, New York.

recharge and discharge conditions; and (3) water quality, 

including concentrations of common ions, trace metals, and 

nutrients. To aid in these descriptions, the following have 

also been included: (1) geohydrologic sections; (2) maps 

and diagrams depicting well locations, geology, groundwater 

levels, and direction of groundwater flow; and (3) tables of 

well records and water-quality data. 

Description of Study Area

The study area is within the northern area of the 

Appalachian Plateau (fig. 2) and is almost 10 miles (mi) long 

and 0.5 to 1.0 mi wide and covers an area of 7.0 square miles 

(mi2), extending northward from the Tompkins County-Tioga 

County border to less than 1 mi south of the City of Ithaca 

in the north (fig. 4). In the southern part of the study area, 

relief between hilltops and the valley floor range from 600 to 

800 ft with hilltop altitudes generally less than 1,900 ft. In the 

northern part of the study area, relief between hilltops and the 

valley floor vary from 500 to 700 ft. Hilltops are higher in the 

southern part of the study area (ranging from 1,600 to 1,870 ft 

in altitude) than in the northern part of the study area (ranging 

from 1,280 to 1,600 ft in altitude) (fig. 4).

76°30' 76°25' 76°20'

42°25'

42°20'

Base from National Geographic 1:100,000 

Topographic, Shaded-Relief Map

Modified from Miller (2009)

0

0

1 2 MILES

1 2 3 KILOMETERS

TOWN OF DANBY

TOWN OF ITHACA

Silt

Dam

Ithaca

Reservoir

Van 

Natta’s

Dam

30 ft

Dam

CAYUGA

LAKE

 TOWN OF DRYDEN

 TOWN OF CAROLINE

 TOWN OF CAROLINE

 TOWN OF DANBY

TOMPKINS CO

04233300 TIOGA CO Bethel Grove

streamgage

04233286

Brooktondale

streamgage

TOMPKINS CO

TIOGA CO

Lower Sixmile Creek

and

Wills

eyville Creek trough

German Cross Road

Upper Sixmile Creek Valley-fill Aq uifer

Belle School Road

EXPLANATION

04233300

Major drainainge basin

Lower Sixmile Creek and Willseville 

trough stratified-drift aquifer boundary

Upper Sixmile Creek

stratified-drift aquifer boundary

U.S. Geological Survey streramgage

station and number

Lower Sixmile Creek Basin

Upper Sixmile Creek Basin

Willseyville Creek Basin

West Branch Owego Creek Basin
6 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

Figure 4. Shaded relief and location of stratified-drift aquifers in the lower Sixmile Creek and Willseyville Creek trough in 

Tompkins County, New York.

76°30' 76°25'

42°25'

42°20'

0 1 2 MILES

0 1 2 KILOMETERS

City of Ithaca

Village 

of Cayuga 

Heights

Town of Ithaca

Town of Town of Danby

Newfield

Village of Lansing

Town 

of 

Lansing

Town of Dryden

Town of 

Caroline

Town of Ulysses

TIOGA COUNTY

TOMPKINS COUNTY

Lower Sixmile Creek and

Wills

e

yville

C

reek trough

Base from U.S. Geological Survey, Seamless Data Distribution System,

accessed in 2008 at http://seamless.usgs.gov/

Universal Transverse Mercator projection, Zone 18

Boundary of stratified-drift 

 aquifer system

EXPLANATION

376–382

382–500

500–600

600–700

700–800

800–900

900–980

980–1,000

1,000–1,075

1,075–1,220

1,220–1,300

1,300–1,400

1,400–1,500

1,500–1,600

1,600–1,700

1,700–1,800

1,800–1,900

1,900–2,000

2,000–2,050

Altitude, in feet, (Datum is NAVD 88)

Northern areastratified-drift 

aquifer 

Central areastratified-drift

 aquifer 

Southern area-

 stratified-drift

 aquifer 

Northern, Central, and Southern 

 extents of the stratified-drift aquifer
Data Collection 7

Previous Studies

The USGS conducted a groundwater investigation of the 

Western Oswego River Basin (Crain, 1974) that included the 

present study area. The investigation by Crain included a well 

inventory and information on (1) geologic and hydrologic 

conditions that control the occurrence of groundwater in 

the basin, (2) quantity of groundwater available, (3) areal 

distribution of available groundwater, and (4) influence of 

groundwater discharge on streamflow. Additional well records 

were collected by Miller (2000) for a general countywide 

aquifer study of Tompkins County. The results of this study 

were used to produce a map report, which delineates the extent 

of unconsolidated aquifers in Tompkins County.

Bedrock geology was mapped by H.S. Williams and 

surficial geology was mapped by R.S. Tarr at a scale of 

1:62,500 (Williams and others, 1909). Surficial geology also 

was mapped at the scale of 1:250,000 by Muller and Cadwell 

(1986) for a statewide reconnaissance mapping study and by 

Miller (2009). The bedrock gorges in the northern part of the 

study area were mapped by Rich and Filmer (1915). Also, 

several outcrops in the northern part of the study area were 

described by Schmidt (1947).

Data Collection

The USGS collected geologic data and stratigraphic 

records by reviewing well drilling records and drilling test 

wells at selected locations. Additionally, seismic-refraction 

surveys were conducted along with water-level measurements 

and groundwater-quality sampling.

Geologic Data

Geologic data were collected by seismic-refraction and 

horizontal-to-vertical (H/V) ambient-noise seismic surveys, 

field reconnaissance for geologic mapping, interpretation from 

topographic maps and orthophoto interpretation, and review 

of available geologic reports, soils maps, and well-drilling 

records. Soils data that were used in geologic interpretation 

were mapped at a scale of 1:20,000 (Neeley, 1961). 

Seismic Surveys

Estimating sediment thickness and the geometry of the 

bedrock surface is a key component of many hydrogeologic 

studies. Seismic-refraction and horizontal-to-vertical (H/V) 

ambient-noise seismic methods were used to estimate the 

depth to bedrock at several selected locations. The seismicrefraction survey method measures refracted compressional 

waves of seismic energy and is based on the time for energy 

generated at a point, such as a small explosive charge, to travel 

through the ground to receivers (geophones). The velocity of 

sound traveling through unsaturated unconsolidated deposits, 

saturated unconsolidated deposits, and bedrock can be 

calculated and used to predict the depth to bedrock. Seismicrefraction techniques used in this study are described by 

Haeni (1988). 

Seismic-refraction surveys were conducted at three 

sites to supplement data from test drilling using a 12-channel 

signal-enhancement seismograph (Haeni, 1988). A series 

of 12 geophones spaced 100 ft apart were inserted into the 

ground, and arrival times of compressional waves generated 

by explosives buried 4 to 5 ft below land surface were 

recorded and plotted as a function of “source-to-geophone” 

distances. Although the water table was relatively shallow 

(generally less than 5 ft below land surface), the unsaturated 

zone was modeled, and a three-layer (unsaturated, saturated 

unconsolidated sediments, and the top of bedrock) boundaryformula, computer analysis (Scott and others, 1972) was used 

to calculate depths to the water table and to bedrock.

The H/V ambient-noise seismic method was also used 

to estimate unconsolidated sediment thickness and map 

the bedrock surface where the use of seismic refraction 

was logistically not feasible. The H/V ambient-noise 

seismic method uses a single, broad-band three-component 

seismometer to record ambient seismic noise. The ratio of 

the averaged horizontal-to-vertical frequency spectrum is 

used to determine the fundamental site resonance frequency, 

which can be interpreted using regression equations to 

estimate sediment thickness and depth to bedrock (Lane and 

others, 2008).

Well Inventory, Test Drilling, and 

Water-Level Measurements

Ninety-nine well records were collected and compiled 

for this report (Appendix 1). Fifty well records were obtained 

from water-well driller’s reports that were submitted during 

the years 2000–09 to the New York State Department of 

Environmental Conservation Water Well Completion Report 

program. The remaining well records were from either existing 

data in USGS files or collected from inventorying individual 

wells during this study. Data from the well drillers’ reports 

include lithologic logs, water levels, estimated well yields, and 

well construction information (well and casing depths, casing 

diameter, and length of casing sticking up above land surface). 

The well inventory data were augmented by test drilling in 

which two wells were installed at one site in the central part 

of the study area using air-rotary drilling methods to obtain 

data on stratigraphy and water levels in this part of the aquifer 

where data were lacking. All records collected for this study 

were entered into the USGS Groundwater Site Inventory 

(GWSI) computer database and are accessible at http://

waterdata.usgs.gov/ny/nwis/inventory.

Levels were run to selected wells to determine the 

altitudes of the water-level-measuring point, (typically the top 

of the casing) and land surface at the well. The altitudes of 

land surface and measuring points of the remaining wells were 
8 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

estimated from USGS 1:24,000 scale topographic contour 

maps and from Light Detection and Ranging (LIDAR) data. 

LIDAR is a remote sensing system used to collect topographic 

data. When possible, depth to water in wells was measured 

using an electric tape. Where measured, depths were converted 

to altitudes, plotted on a map, and contoured to depict the 

water table in unconfined aquifers and potentiometric surfaces 

in the confined aquifers. Historic water levels were used 

to help determine the potentiometric surfaces depicted for 

this report because of the paucity in some areas of available 

wells to measure. Because the contour interval used to depict 

groundwater surfaces was greater than any historic or modern 

seasonal fluctuations, their use was justified.

Water Sampling and Analysis

Groundwater samples were collected from six wells 

during 2006–07 and sent to the USGS National Water 

Quality Laboratory (NWQL) in Denver, Colorado, to be 

analyzed for common ions, trace metals, and nutrients. Field 

measurements were made for pH, specific conductance, and 

water temperature. The samples were collected and processed 

by methods described in the USGS manual for the collection 

of water-quality data (U.S. Geological Survey, 2004). 

Analytical results for selected constituents are compared 

with Federal drinking-water standards. The standards include 

Maximum Contaminant Levels (MCLs), Secondary Maximum 

Contaminant Levels (SMCLs), and Health Advisories (HAs) 

established by the U. S. Environmental Protection Agency 

(USEPA, 2006).

All six samples were collected from wells finished in 

sand and gravel. Of the six samples, four were from domestic 

wells, and two were from test wells installed during this 

study. For domestic wells, the well pump was run for about 

20 minutes (or until at least three casing volumes of well water 

had been purged from the casing) then a raw-water spigot 

between the well and the pressure tank was opened, and the 

water was allowed to run for several more minutes to flush the 

spigot. Finally, the samples were collected from the raw-water 

spigot to avoid all influences from water-treatment systems 

and to ensure that the water collected was representative of 

the water in the aquifer. In unused test wells, a stainless-steel 

submersible pump was used to purge the well of from 5-to-10 

casing volumes of water before collecting the water samples.

Geology 

Geologic materials in the study area include 

sedimentary bedrock, unstratified drift (till), and stratified 

drift (glaciolacustrine and glaciofluvial deposits), and recent 

alluvium. Bedrock that underlies the study area consists of 

shale, siltstone, and fine-grained sandstone that were deposited 

in seas during the Devonian Period (416–359.2 million 

years ago). The rocks were uplifted during the Alleghanian 

Orogeny in the Late Paleozoic time (about 330 to 250 million 

years ago) and subsequently have undergone dissection by 

streams (Isachsen and others, 1991) and scouring by glaciers. 

Bedrock is overlain by unstratified drift (till) and stratified 

drift (unconsolidated sediments) except locally where bedrock 

crops out at land surface. These outcrop areas are present in 

ditches along roads, and in stream channels that are high up on 

the trough walls, and in interglacial and interstadial gorges that 

had been re-excavated by post-glacial streams. 

Glacial History

The study area has undergone several major glaciations 

during the Pleistocene Epoch (table 1), commonly referred to 

as the Ice Age, which began 2.6 million years ago and ended 

11,850 years before present (BP), with the end date expressed 

in radiocarbon years (Fullerton, 1980). Each subsequent 

glaciation effectively obliterated most of the previously 

deposited sediments; therefore, most of the sediments 

were deposited during and after the last glacial episode 

(Wisconsinan glaciation). 

During the Wisconsinan glaciation, the Laurentide Ice 

Sheet expanded southward from northeastern Canada. As the 

main sheet ice encountered the Adirondack Mountains, a lobe 

(Ontario Lobe) flowed into the Lake Ontario Basin (fig. 2) 

where it then spread southward and covered central New York. 

The maximum extent of the ice reached northern Pennsylvania 

about 23,000 to 24,000 years before present (Muller and 

Calkin, 1993). Most of the geologic history in this study 

area reflects the events that occurred when the Ontario Lobe 

advanced into and retreated from central New York.

During the Wisconsinan glaciation, the climate had 

undergone several cycles of climate cooling and warming 

resulting in oscillations of the ice front. A cold period that 

caused the glacier to expand is called a stadial, and a warm 

period that caused the glacier to retreat is called an interstadial 

(table 1). Stadials and interstadials are of insufficient duration 

or intensity to be considered a glacial period, however. Some 

oscillations of the ice were regional and may have reflected 

major changes in climate, whereas other oscillations were of 

a local extent and may have reflected changes to ice dynamics 

and interaction of ice with proglacial lakes. In this study 

area, most sediment was deposited during Nissouri and Port 

Bruce Stades, Erie Interstade, and post-glacial time (table 1). 

However, in some places, Middle Wisconsinan sediments 

had escaped erosion by the last glacial episode because these 

sediments were in settings protected from scouring by Late 

Wisconsinan ice. Schmidt (1947) and Ashworth and others 

(1997) found detrital wood of Middle Wisconsinan age in 

sediments at bluffs of Sixmile Creek that was dated from 

27,000 to greater than 41,900 radiocarbon years BP. 

During the Erie Interstade (about 15,500 to 

16,500 years BP, table 1), the ice retreated northward from 

Pennsylvania and is believed to have melted back north of 

the study area, but the location of the ice margin during the 
Geology 9

Table 1. Time-stratigraphic classification of Pleistocene stades and interstades in northeastern North America. After 

Dreimanis and Karrow (1972) and Fulton and others (1984).

System PeriodSystem EpochStageSubstage

Stades and Interstades

YearsBeforePresent

Post glacial erosion and deposition by 

recent streams

Port Huron Stade 13,000 Mackinaw Interstade

HoloceneHolocene Wisconsinan

Pleistocene

Two Creeks Interstade

Nissouri Stade

Port Bruce Stade

Erie Interstade

Early Wisconsinan

Nicolet Stade

Plum Point Interstade

Middle Wisconsinan

New York is ice free

Ice retreats north of Ithaca

23,000

32,000

53,000

Guildwood Stade

63,000

36,000

Cherrytree Stade

Port Talbot Interstade

Valley Heads readvance—forms massive 

moraines

Wisconsinan ice sheet spreads across 

New York

Ice retreats north of Ithaca

13,500

15,500

16,500

Events that affected the study area

Table 1. Time-stratigraphic classification of Pleistocene stades and interstades in northeastern North America. 

After Dreimanis and Karrow (1972) and Fulton and others (1984). Quaternary

11,850

12,500

Late Wisconsinan

Remnants of Middle 

Wisconsinan sediments in 

lower Sixmile Creek Valley 

(Schimdt, 1950) 

St. Pierre Interstade

68,000

75,000
10 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York 76°24' 76°26' 76°28' 42°26' 42°24'

42°22'

Surficial geologic units

EXPLANATION

E ́

D ́

C ́

B ́

E

D

C

F

Brooktondale delta

 area
Geology 11Figure 5. Surficial geology of the lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York.

42°22'

42°20'

0 1 2 MILES

0 1 2 KILOMETERS

Surficial geologic units

WaterSwamp deposits

Alluvial fan

Alluvial terraceAlluvium

Delta (deposited by small tributaries)Delta (Brooktondale Delta) glaciofluvial deposits

Post glacial alluvium

Inwash over kamesKame depositsKame moraine (Valley Heads Moraine)OutwashMostly till (Valley Heads Moraine)  with some thin glaciolacustrine  and inwash sediments in some places

Till

UndifferentiatedBedrock (Shale, Siltstone, and  Fine Sandstone)

600-foot inertstadial bedrock gorge

Abandoned channel

Sand and gravel mine

Cityscape (Ithaca)

Line of geologic section

Stratified-drift aquifer system boundary

A A ́

EXPLANATION

Fill

Base from U.S. Geological Survey, Seamless Data Distribution System,accessed in 2008 at http://seamless.usgs.gov/Universal Transverse Mercator projection, Zone 18

Proglacial 

lake

outlet

channel

Flow

C ́

A ́

B ́

C

B

A

F ́

Ridgeway Road
12 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

retreat is uncertain (Muller and Calkin, 1993) because there 

are no radiocarbon data in New York for this period. Instead, 

evidence for the Erie Interstade is based on circumstantial 

data (Dyke and others, 2002). Ice readvanced into the study 

area during the Port Bruce Stade (about 15,500 years BP, 

table 1) and deposited a massive moraine (Valley Heads 

Moraine) extending from Brooktondale in the north to the 

boundary between Tompkins and Tioga Counties in the south 

(fig. 5). During this period, the ice likely surged back and 

forth in some places as evidenced by multiple till layers and 

disturbed deposits. The glacier retreated rapidly north from 

the Valley Heads ice starting around 14,400 years BP (Muller 

and Calkin, 1993) and probably took several hundred years to 

retreat north of the study area (Fullerton, 1980). The multiple 

advances and retreats of the ice during stadial and interstadial 

periods, the minor surges of ice, and remnants of older pre-late 

Wisconsinan deposits that survived the last glacial episode 

resulted in a complex array of multiple sequences of deposits 

in the study area that, in some places, make it difficult to 

correlate and map continuous geologic units. 

Scouring by Ice

Scouring by flowing ice and subglacial meltwaters played 

a major role in modifying the preglacial landscape in the study 

area. In the uplands, scouring by ice extensively smoothed 

bedrock hillsides and slightly lowered hilltops. In the lower 

Sixmile Creek and Willseyville Creek valleys, extensive 

scouring by ice and erosion by subglacial meltwaters truncated 

hillside spurs, formed U-shaped transverse valley profiles, 

smoothed valley walls, and deepened the valleys by as much 

as 300 ft, all of which resulted in a continuous trough (fig. 6). 

Lower Sixmile Creek and Willseyville Creek valleys were 

extensively deepened and widened because they were aligned 

with the direction of ice flow (roughly north to south). In 

north–south oriented valleys, the ice was a greater erosional 

agent because it was thicker and flowed faster than in the 

uplands and in east–west oriented valleys. The east–west 

oriented upper Sixmile Creek valley (fig. 3) was perpendicular 

to the direction of ice movement and, consequently, 

underwent less scouring than lower Sixmile Creek valley. 

Upper Sixmile Creek valley is known as a “hanging valley” 

because it has a bedrock floor that is several hundred feet 

higher than the bedrock floor in the lower Sixmile Creek 

and Willseyville Creek trough. At Brooktondale, Sixmile 

Creek exits the hanging valley by plunging down a series of 

waterfalls and cascades in a bedrock gorge (fig. 3), and where 

it enters the trough, it flows back onto a thick sequence of 

unconsolidated deposits.

In some areas, the trough may be asymmetrical with 

one side steeper than the other, whereas in other areas, the 

trough walls are symmetrical. As the trough intrudes further 

southward into the Appalachian Plateau (fig. 2), the width 

of the trough decreases and the transverse valley profile 

transitions from a broad U-shaped profile in the north to a 

narrow U-shaped profile in the south. 

Scouring by ice was also responsible for removing 

the former (preglacial) bedrock col (a high, narrow pass or 

depression in upland areas, generally across a ridge or through 

a divide, or between two adjacent hills) in the southern part 

of the study area (fig. 6) that once formed the major surfacewater divide between the St. Lawrence River Basin and the 

Susquehanna River Basin. The bedrock col that had formed 

the divide has been replaced by an accumulation of more than 

200 ft of glacial drift that is mantled in some places by 10 to 

30 ft of recent alluvial sand and gravel. The present divide 

between the St. Lawrence River Basin and the Susquehanna 

River Basin is coincident with an upland tributary that has 

built an alluvial fan on the thick glacial-drift deposits at Belle 

School Road in the southern part of the study area (fig. 3). 

Wisconsinan Deposits in the Study Area

The drift in the study area consists of unstratified 

glacial drift (till), stratified glacial drift (glaciolacustrine 

and glaciofluvial deposits), and some post-glacial stratified 

sediments (lake-bottom sediments that were deposited in 

reservoirs, peat and muck that were deposited in wetlands, and 

alluvium deposited by recent streams). The surficial geology 

of the study area is shown in figure 5. Most of the drift in the 

study area consists of fine-grained sediments such as till and 

glaciolacustrine fine sand, silt, and clay that are interlayered 

with lesser amounts of coarse-grained sediments such as 

sand and gravel. Although coarse-grained sediment (sand and 

gravel) is usually a minor component of the valley fill, it is 

present in sufficient amounts in most places within the trough 

to form the aquifers that most residents use for their water 

supply. Locally, the sand and gravel deposits can be as much 

as 100 ft thick, such as at the delta near Brooktondale in the 

central part of the study area, but in most places the sand and 

gravel deposits range in thickness from 10 to 20 ft. 

The thickness of drift ranges from zero where bedrock 

crops out at land surface, such as in gorges and along the 

trough walls, to more than 300 ft in the middle of the trough 

in the central and southern parts of the study area. The drift 

progressively thins northward where Sixmile Creek enters the 

trough near Brooktondale because the stream progressively 

cuts deeper and deeper into the drift as it flows northward. 

Eventually, Sixmile Creek erodes through all of the drift and 

flows on top of the bedrock north of the Ithaca Reservoir. 

The unstratified glacial drift in the study area consists of 

till, which is an unsorted mixture of clay, silt, sand, gravel, 

and rocks that were deposited directly by glacial ice, rather 

than by meltwater. The larger gravel and rock clasts, which 

are typically embedded in a fine-grained matrix consisting 

of clay, silt, and very fine sand, range in size from pebbles 

to boulders. In most places in the uplands, a layer of till that 

directly overlies bedrock is the sole unconsolidated deposit, 

whereas, in the trough, there are typically two or more till 
Geology 13

Figure 6. Bedrock structure map of lower Sixmile Creek and Willseyville Creek trough Tompkins County, New York.

076°27'30" 076°25'0" 076°22'30"

42°25'0"

42°22'30"

42°20'0"

0 2,000 4,000 FEET

0 500 1,000 METERS

800

900

700

1,100

1,000

1,000

600

500

800

800

1,100

1,100

1,100

900

900

700

1,000

1,000

800

1,000

800

1,100

1,100

1,000

700

700

900

900

1,000

600

800

800

700

900

900

700

1,100

1,000

900

800

700

800

900

700

1,100

1,000

1,000

600

500

800

800

1,100

1,100

1,100

900

900

700

1,000

1,000

800

1,000

800

1,100

1,100

1,000

700

700

900

900

1,000

600

800

800

700

900

900

700

1,100

1,000

900

800

700

EXPLANATION

900 Bedrock contour—Shows approximate altitude of bedrock 

surface. Contour interval 100 feet. Datum is National Geodetic

Vertical Datum of 1929

Buried interglacial bedrock gorge (600 ft gorge)—The oldest 

buried gorge in Sixmile Creek valley first described by Rich 

and Filmer (1915)

Boundary of stratified-drift aquifer system 

Base from U.S. Geological Survey, Seamless Data Distribution System,

accessed in 2008 at http://seamless.usgs.gov/

Universal Transverse Mercator projection, Zone 18

Former bedrock

col that formed 

the preglacial 

drainage divide

was somewhere

in this reach of 

the valley

Van Natta’s dam

30 ft

dam

Ithaca

Reservoir

Silt

Dam
14 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

units that are interlayered with stratified drift. In general, till 

comprises a large portion of the drift in the study area, and in 

the northern part of the trough (north of the delta just west of 

Brooktondale), till is the prevalent type of deposit, especially 

in the upper portion of the valley fill where it typically crops 

out at land surface (fig. 5). 

The stratified glacial drift (glaciolacustrine and 

glaciofluvial deposits) consists of layered and sorted sediment. 

Glaciolacustrine deposits include deltas and lake-bottom 

sediments. One example of a glaciolacustrine deposit is 

the large delta west of Brooktondale in the central part 

of the study area (fig. 5). Deltas typically consist of three 

components: (1) topset beds—coarse-grained sediments (sand 

and gravel) that were deposited on the upper part of the delta 

in near-shore subaerial environments, (2) foreset beds—

relatively steeply dipping, medium-coarse sediments (mostly 

sand and pebbly sand) deposited in shallow water at the front 

of the delta shore, and (3) bottomset beds—relatively flatlying beds of fine-grained sediments (fine sand, silt, and clay) 

deposited in deep water at distal parts of the delta. 

Glaciofluvial deposits consist of layered coarse-grained 

sediments (sand and gravel) that were deposited by meltwaters 

that flowed on top, within, and below the glacier. Meltwater 

that flowed through an internal network of openings and 

on top of the ice discharged at the ice front and deposited 

heads of outwash and outwash plains. Meltwaters deposited 

sediments on top and within the ice and these sediments were 

laid down as the ice disintegrated and formed kame deposits. 

Meltwaters that were routed through tunnels at the base of 

glacier deposited subglacial features, such as eskers and 

subglacial outwash fans.

Southern Part of Study Area 

The prominent geologic feature in the southern part of 

the study area is a large moraine that was deposited at the 

terminus of a stagnant ice lobe that extended several miles 

south from the main ice massif and into the study area (fig. 5). 

The moraine is part of the most extensive moraine system in 

New York State—the Valley Heads Moraine system that forms 

a roughly 240-mi-long discontinuous ridge across central and 

western New York (fig. 2).

The Valley Heads Moraine system was formed during 

a readvance of ice during the Port Bruce Stade about 

15,500 years ago (Muller and Calkin, 1993). In this study area, 

the moraine extends 4 mi from just south of Brooktondale 

to the southern border of Tompkins County (fig. 5). Randall 

(2001) identified the Valley Heads Moraine and the area on the 

backside of the moraine as one of the regions where multiple 

drift layers are widespread and hydrologically important. 

Evidence for multiple readvances and retreats includes the 

presence of multiple till units and disturbed sediments (caused 

by thrust faults, folds, or erosion by ice) within, or on top of, 

previously deposited glacial sediments. Evidence for the Erie 

Interstade also comes from the fine-grained matrix of the till 

that was originally sediment deposited in proglacial lakes, 

which became incorporated into advancing ice and included in 

the till. Because the ice was thin at the terminus of the glacier, 

it probably did not completely erode the previously deposited 

sediments down to bedrock. Instead, the relatively thin ice 

overrode and partially eroded previously deposited sediments 

and deposited another sequence of till and glaciofluvial 

sediment over the older deposits. 

The topography of the moraine includes hummocky 

kames and kettles, kame terraces, and a large channel, carved 

by water that was an outlet to a post-glacial lake in the trough. 

The kame and kettle ice-disintegration landforms and the 

absence of ridges are topographic evidence that indicate that 

the margin of Valley Heads ice melted under stagnant ice 

conditions. The moraine is composed of sediments that were 

transported by the ice and by meltwaters that flowed beneath, 

within, and on top of the ice, as well as local sediments 

(alluvial inwash), transported by upland streams, that were 

deposited on or between the ice and adjacent trough walls. 

Records of wells finished in the morainal deposits indicate 

that the types of sediments that may be penetrated are till, 

glaciofluvial sand and gravel, and glaciolacustrine fine sand, 

silt, and clay. The actual contact of stratigraphic units between 

wells is difficult to predict due to the collapse and continual 

movement of sediment laid down as the ice melted. Hence, 

due to the chaotic depositional environment and relatively 

sparse geologic data in the moraine, little is known about the 

stratigraphy of the deposits that comprise it.

Although there is little data on the extent and thickness 

of stratigraphic units at the moraine, the total thickness of 

the drift at the Valley Heads Moraine where Ridgeway Road 

traverses the trough in the southern part of the study area was 

determined using refraction and horizontal-to-vertical (H/V) 

ambient-noise ratio seismic methods (figs. 5, 6, and 7). The 

results of the seismic surveys indicate that the drift is as much 

as 300 ft thick in the center of the trough and that the part 

of the trough where depths to bedrock are between 200 and 

300 ft may represent an extension interglacial "600 ft gorge" 

(fig. 7).

In the low area of the trough, there is a 4-mi-long wetland 

that represents the vestige of a small shallow proglacial lake 

and its outlet channel that formed in a basin between the front 

of the retreating ice and the crest of the moraine (fig. 5). The 

altitude of the surface of the lake was controlled by the outlet 

channel on the moraine (fig. 5) that initially was at an altitude 

of about 1,010 ft before the outlet began to incise into the 

moraine. Then, as the outlet channel was lowered by incision, 

the lake level gradually dropped about 60 ft and (altitude about 

950 NVGD 88), as indicated by the present altitude of the 

bottom of the abandoned outlet channel in the southern part of 

the study area.

Central Part of the Study Area

Glaciolacustrine processes were responsible for 

the prominent geologic features in the central part of the 

study area. In the proglacial lakes that formed during the 
Geology 15

Figure 7. Geohydrologic section A–A’ showing results of horizontal-to-vertical (H/V) ambient-noise and 

seismic-refraction surveys along Ridgeway Road, Town of Caroline, New York.

EXPLANATION

Well and well number—Number is 

assigned by U.S. Geological Survey. Well 

data are in Appendix at end of report

H/V

Horizontal-to-vertical (H/V) ambient-noise 

seismic survey site

velocity = 5,600 feet per second H/V H/VH/V

1,200

1,150

1,100

1,050

1,000

950

900

850

800

750

700

650

VERTICAL EXAGGERATION X 10

VERTICAL DATUM IS NATIONAL GEODETIC VERTICAL DATUM OF 1929

Seismic-refraction

survey

Seismic-refraction

survey

TM1590

TM1590

Saturated unconsolidated deposits

Unsaturated unconsolidated deposits H/V

TM2381

(projected)

A A ́

Bedrock (siltstone and shale)

velocity = 13,800 feet per second

velocity = 1,900 feet per second

FEET

Southwest Northeast

FEET

0 1,000 2,000 3,000 4,000 5,000 
16 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

Figure 8. Geohydrologic section B–B’ in the lower Sixmile Creek and Willseyville Creek trough, Town of Caroline, New York.

advance and retreat of ice in the central part of the trough, 

glaciolacustrine sediments accumulated (fig. 8) between the 

retreating ice and the morainal deposits that plugged the valley 

in the south part of the study area. Fine-grained sediments 

(lake-bottom fine sand, silt, and clay) were deposited in deep 

water, and coarse-grained sediments (deltaic sand and gravel) 

accumulated at the water’s edge and in shallow water. 

A large delta (Brooktondale Delta) was deposited 

west of Brooktondale when ice in lower Sixmile Creek and 

Willseyville trough retreated north of the mouth of upper 

Sixmile Creek valley, thereby unblocking upper Sixmile Creek 

valley and permitting sediments transported by Sixmile Creek 

to be disgorged into the proglacial lake in the trough. Most of 

the sediment was deposited into standing water, but at times, 

some may have been deposited against and on top of the ice 

during surge(s) of the glacier back into the Brooktondale area. 

The delta extends from its apex at the east side of the trough to 

the central part of the trough to the west (fig. 9). 

VERTICAL EXAGGERATION X 10

VERTICAL DATUM IS NATIONAL GEODETIC VERTICAL DATUM OF 1929

 FEET

EXPLANATION

Bedrock (shale and siltstone)—Forms the bottom confining unit that 

underlies the basal confined sand and gravel aquifer

Deltaic sand and gravel—May form a minor unconfined 

aquifer; however, this unit has been extensively mined for 

aggregate and may be thin or absent in places

Sand and gravel (unknown origin)—Forms confined aquifer units; 

however, some of these unit may be thin or discontinuous in places. 

Origin may be either glaciofluvial (meltwaters transported) or inwash.

Glaciolacustrine silt and clay—Forms confining units

Till—Poorly sorted clayey silt matrix with embedded stones, 

compact, dense 

Glaciolacustrine sand—Forms aquifer units where 

comprised of medium to coarse sand; forms semi-confining 

units where composed of very fine to sand

TM 560

Well and well number—Number is assigned by U.S. Geological Survey. 

Well data are in Appendix at end of report

Water level marker

Alluvium—Recent alluvial deposits

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000

1,150

1,050

950

850

750

650

TM1683

TM2333 (projected)

TM2568

TM1533

TM1019

Beaver Brook

TM 588, flows (projected)

TM2367

TM1008 (projected)

TM 50, 51

TM 555 (projected)

Abandoned ice-margianl channel

TM 560

TM1698, flows

TM2100

Unknown Unknown

B B ́

FEET

West East
Geology 17

thinner and finer-grained towards its edges. At well TM2367 

(fig. 8), and near the southern boundary of the delta, the 

deposits are only 25 ft thick.

Northern Part of the Study Area

The three major geologic processes that have been 

instrumental in forming the geologic framework in the 

northern part of the study area are (1) erosion by streams 

during interglacial and post-glacial periods, (2) deposition in 

the upper zones of the drift that was dominated by subglacial 

environment (till and subglacial meltwater deposits), 

Figure 9. Geohydrologic section C–C’ in the lower Sixmile Creek and Willseyville Creek trough, Town of Caroline, New York.

The delta consists of medium-to-coarse sand to pebbly 

sand (foreset beds) in the lower part of the delta and coarse 

gravel on top of the delta (topset beds). Presently, the delta 

is mined for aggregate; subsequently most of the upper part 

of the delta has been removed by this process. Before sand 

and gravel mining began, the delta was as much as 80 to 

100 ft thick. The results of drilling at an USGS test-well site 

(TM1008, fig. 8) in the bottom of one of the sand and gravel 

pits indicted that there was 24 ft of surficial sand and gravel 

remaining below the bottom of the pit at that site. The deltaic 

sediments are thickest (as much as 100 ft thick) and coarsest at 

the apex of the delta in the east side of the trough and become 

VERTICAL EXAGGERATION X 10

VERTICAL DATUM IS NATIONAL GEODETIC VERTICAL DATUM OF 1929

 FEET

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000

1,150

1,050

950

850

750

650

TM2399

TM2064

TM2128

TM1008, TM1009

TM2282

TM1019 (projected)

Delta eroded by

Beaver Brook Delta mined for aggregate Beaver Br.

Original surface of Brooktondale delta

C C ́

Unknown

Unknown

?

?

?

?

?

?

?

? ?

?

?

?

Brooktondale delta 

FEET

East West

EXPLANATION

Bedrock (shale and siltstone)—Forms the bottom confining unit that 

underlies the basal confined sand and gravel aquifer

Water table in Brooktondale delta (unconfined aquifer)

Deltaic sand and gravel—May form a minor unconfined aquifer; 

however, this unit has been extensively mined for aggregate and may 

be thin or absent in places

Sand and gravel (unknown origin)—Forms confined aquifer units; 

however, some of these units may be thin or discontinuous in places. 

Origin may be either glaciofluvial (meltwaters transported) or inwash

Glaciolacustrine silt and clay—Forms confining units

Till—Poorly sorted clayey silt matrix with embedded stones, compact, dense 

Glaciolacustrine sand—Forms aquifer units where comprised of medium

to coarse sand; forms semi-confining units where composed of very fine to sand

TM 560

Well and number—Number is assigned by U.S. Geological Survey. Well 

data are in appendix at end of report
18 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

and (3) deposition in the lower zone of the drift that was 

dominated by glaciolacustrine (lake-bottom) and subglacial 

environments. Deposition of coarse-grained sediments 

(sand and gravel) was subordinate in the northern part of 

the trough, and there is a conspicuous absence of substantial 

amounts of glaciolacustrine sediments and sand and gravel 

at land surface. Surficial glaciolacustrine sediments and sand 

and gravel also are absent in other valleys that are crossed 

by the Valley Heads Moraine in central New York, (Miller 

and Randall, 1991). The lack of glaciolacustrine sediments 

at land surface is likely attributed to the absence of a major 

proglacial lake in the northern part of the study area; instead 

of a lake, there probably was highly disintegrated stagnant 

ice in the trough during the late phases of ice retreat in which 

meltwater had reversed direction in flow (from south to north) 

and moved back under the disintegrating ice through crevasses 

and tunnels and drained out to a lower outlet in another 

valley (Miller and Randall, 1991; Cadwell and others, 1988; 

Cadwell, 1972).

There are scant subsurface data in the trough north of 

German Crossroad because much of the area is composed of 

dams and reservoirs and most residents that live in this area 

are supplied by a public-water system (City of Ithaca) rather 

than by individual wells. Most geohydrologic information 

about this area is from test holes drilled near the Ithaca 

Reservoir and observations of outcrops exposed in bluffs 

along Sixmile Creek and in gullies cut by tributaries that drain 

the steep walls of the trough. Schmidt (1947) describes several 

varved glaciolacustrine units in the lower parts of eroded 

bluffs that were exposed by down cutting by Sixmile Creek 

just south of the Silt Dam; the units are interlayered with thin 

sand and gravel units in the lower parts of the drift. These 

deposits are overlain by a thin sand and gravel unit which, in 

turn, is overlain by till (fig. 10). 

Till comprises most of the upper portion of drift between 

German Crossroad and Banks Road. Mostly till and disturbed 

lacustrine deposits (lake deposits that became overridden by 

ice or have undergone mass slumping) consisting of silt and 

clay, and some lenses of sand and gravel comprise the lower 

portion of the drift (fig. 11). Well TM1002 was reported to be 

cased to 88 ft below land surface and is finished in a confined 

sand and gravel aquifer that is probably on top or close to 

bedrock (fig. 10). Results of a seismic-refraction survey 

(fig. 10) indicate that the buried “600 ft gorge” extends at least 

this far south in the trough.

Since intervals of interglacial periods have been 

longer than the present post-glacial period, the ancestral 

streams in lower Sixmile Creek valley had a longer time to 

erode previously deposited sediments. In some places, the 

interglacial stream had fully penetrated (completely incised) 

the drift and had cut a gorge into the underlying bedrock. 

An interglacial gorge (called the “600 ft gorge” by Rich and 

Filmer, 1915) extends from Van Natta’s Dam in the north to 

at least German Crossroad. Some well records indicate that it 

probably underlies the central part of the study area (figs. 6, 

10, 11, and 12) and could possibly extend beneath the southern 

part of the study area. Another buried gorge (called the “200 ft 

interstadial gorge” by Rich and Filmer, 1915) extends north 

from Van Natta’s Dam beyond the northern part of the study 

area (fig. 12). The “200 ft interstadial gorge” contains little or 

no unconsolidated sediments, and consequently, no sand and 

gravel aquifer is present in this area.

In the northern part of the study area just north of the 

Brooktondale delta, the drift in areas not incised by streams 

is more than 200 ft thick and progressively thins northward to 

less than 100 ft at the northern end of the study area (fig. 11). 

However, the thickness of the drift is much less in the northern 

part of the study area where streams have eroded much of 

the drift during post-glacial time. During the post-glacial 

period, Sixmile Creek and many of the tributaries that drain 

the trough walls have deeply incised channels creating ravines 

and gullies, some that are cut more than 100 ft deep into the 

drift. Near the silt dam (figs. 3 and 6), Sixmile Creek has cut 

a channel over 100 ft deep and 1,000 ft wide that penetrates 

most of the drift and is close to the top of bedrock in the 

U-shaped trough floor (fig. 11). North of the “60 ft Dam,” at 

the outlet of the Ithaca Reservoir (fig. 6), Sixmile Creek has 

fully penetrated the drift and has entered the “600 ft gorge”.

Hydrology of the Stratified-Drift 

Aquifer System

Characterization of the stratified-drift aquifer system 

in the lower Sixmile Creek and Willseyville Creek trough 

included describing the (1) aquifer type (confined or 

unconfined); (2) aquifer framework; (3) groundwater-flow 

system, including water levels and recharge and discharge 

conditions; and (4) water quality, including concentrations of 

inorganic chemical constituents and nutrients. Because drilling 

is expensive and access to desired locations is sometimes 

not possible, most data used to characterize the geologic 

framework of the aquifers are obtained from existing well 

records. Many of the wells used in this study are within the 

central portion of the study area; however, attempts were 

made to characterize the southern and northern portions of 

the aquifer system using available well logs, water-level data, 

and correlations made from seismic data. The locations of 

wells used to characterize the stratified-drift aquifer system 

are shown in figure 13, and well records are presented in 

Appendix 1.

There are three types of aquifers in the lower Sixmile 

Creek and Willseyville Creek trough — confined, unconfined, 

and a combination of both (fig. 14). Based on aquifer type, 

the distribution of aquifers is summarized as follows: (1) an 

unconfined aquifer aquifer in the southern area of the trough, 

(2) an unconfined deltaic aquifer (underlain by a confined 

aquifer) in the central part, and (3) confined aquifers at 

various depths throughout the trough (locally overlain by 

discontinuous unconfined aquifer material).
Hydrology of the Stratified-Drift Aquifer System 19

Figure 10. Geohydrologic section D–D’ in the lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York.

D D ́

FEET

Southwest Northeast Bend in section TM1002 TM2039TM1423 TM1319 (projected) TM1281 (projected) TM 92

FEET

600

700

800

900

1,000

1,100

1,300

1,200

1,400

1,500

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 11,000 12,000

VERTICAL EXAGGERATION X 10

VERTICAL DATUM IS NATIONAL GEODETIC VERTICAL DATUM OF 1929

Top of till

(base of 

Wisconsinan ice)

Preglacial

valley

Inner glacial

trough

Interglacial 

600 foot buried gorge

Outer glacial

trough

TM 92

EXPLANATION

Alluvium—Recent alluvial deposits

Sand and gravel (unknown origin)—Form confined aquifer units; 

however, some of these units may be thin or discontinuous in places

Till—Clayey silt matrix with embedded stones, poorly sorted, compact, dense 

Bedrock (Devonian shale and siltstone)—Forms the bottom confining unit that 

underlies the basal confined sand and gravel aquifer

Well and number—Number is assigned by U.S. Geological Survey

Seismic-refraction

survey (projected)
20 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

Figure 11. Geohydrologic section E–E’ in the lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York.

0

600

700

800

900

1,000

1,100

1,200

1,300

1,400

1,500

500

1,000 2,000 3,000 4,000 5,000 10,000

FEET

6,000 7,000 8,000 9,000 11,000 12,000 13,000 14,000

EXPLANATION

Alluvium—Recent alluvial deposits that overlie the glaciolacustrine deposits

Sand and gravel (unknown origin)—Forms confined aquifer units; 

however, some of these units may be thin or discontinuous in places. 

Origin may be of either glaciofluvial (meltwaters transported) or inwash

(Alluvium transported from uplands and deposited in the valley)

Glaciolacustrine silt and clay—Forms confining units

Till (Wisconsinan)—Poorly sorted clayey silt matrix with embedded stones, 

compact, dense 

VERTICAL EXAGGERATION X 10

VERTICAL DATUM IS NATIONAL GEODETIC VERTICAL DATUM OF 1929

Inner glacial 

trough

Interglacial 600 foot 

buried gorge

Top of till 

(base of 

Wisconsinan ice) Outer glacial

trough

Inner glacial 

trough

Bedrock (Devonian shale and siltstone)—Forms the bottom confining unit that 

underlies the basal confined sand and gravel aquifer

E E ́

Interglacial 600 foot 

buried gorge

FEET

Southwest Northeast
Hydrology of the Stratified-Drift Aquifer System 21 Figure 12. Geohydrologic section F–F’ of glacial and fluvial systems in the Sixmile Creek and Willseyville Creek trough, Towns of Caroline, Dryden, and Ithaca, New York.

5,000 0 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000 55,000

1,000

900800700600500400

1,100

300

F F ́

EXPLANATION

Datapoint— Bottom of U-shaped bedrock glacial trough

Datapoint— Bottom of older (600 foot) interstadial gorgeDatapoint

— Bottom of younger (200 foot) interstadial gorge

Bottom of younger (200 foot) interstadial gorge

Confluence of Sixmile Creek and Beaver Brook

Bottom of U-shaped bedrock glacial trough

Bottom of older (600 foot) interglacial gorge

Profiles are based on exposures, well logs, and seismic data, all extrapolated to the estimated thalwegs of the respective systems, which are not necessarily coincidental or in the center of the valley.

Land surface

Top surface, uneroded, postglacial land surface (mostly till)

Channel of Sixmile CreekChannel of Beaver CreekChannel of Willseyville Creek

Well TM1019(depth 304 ft) did not encounterbedrock

Ridgeway Rd

Drainage divide Brooktondale delta

White Church Rd 

30 ft Dam

60 ft Dam

Silt

ReserSilt Dam

voir

German Crossroad

Banks Road

Ithaca

Reservoir

Columbia St Bridge

Van Natta’s Dam

Northwest Southeast

VERTICAL EXAGGERATION X 25

VERTICAL DATUM IS NATIONAL GEODETIC VERTICAL DATUM OF 1929

?

Flow Flow

SECTION

SECTION

SECTION

SECTION

E-E ́

D-D ́

B-B ́

C-C ́

SECTION

A-A ́

FEET, NGVD 1929

FEET
22 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

76°22'30" 76°25' 76°27'30"

42°25'

42°22'30"

!.

!.

!.

!.

!.

!.!.

!.!.

!.

!.

!.

!.!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

TM1029

TM 92

TM 60

TM 58

TM 86

TM2568

TM2399 TM2311

TM1506

TM1320

TM2369

TM2333

TM2315

TM2282

TM2367

TM1008,

 TM1009

TM2355

TM1019

TM1281

TM1295

TM1004

TM1896

TM1423

TM1319

TM1002

TM2039

TM1003

TM2100

TM 555

TM 560

TM2064

TM1914

TM1898 TM1760

TM1732

TM50

TM1683

TM1533

!.

TM1503 TM1532 TM 550

TM 551

TM 552

TM 544

TM1309 TM 65

TM1001

TM 987

TM1979

TM 983

TM 984

TM1645

TM1040

TM1044

TM1043

TM1039

TM1041

TM1042

TM 558

TM1045

TM2617

TM2128

TM 1698

TM51

TM2717

!.

!.

!.

!.

!.

German r C so rs oad

Rd

Banks

Road

Burns
Hydrology of the Stratified-Drift Aquifer System 23Figure 13. Location of wells in lower Sixmile Creek valley and Willseyville Creek trough, Tompkins County, New York. Base from National Geographic 1:100,000 Topographic, Shaded-Relief Map

42°20'

0 2,000 4,000 FEET

0 500 1,000 METERS

!.

!.!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!. !.

!.

!.!.

!.

!.

!.

!.

!.

!.

!.

!.

TM2568

TM2369

TM2333

TM2269

TM2315

TM2381 TM2188

TM2360

TM 42

TM1408

TM1611

TM2100

TM1983,

TM2005

TM1732

TM50

TM1683

TM1677

TM 32

TM1671

TM1590

TM1533

TM1380

TM1355

TM1296

TM 21

TM1260

TI 757

TM1251

TM 558

TI 758

TI 750

EXPLANATION

Well and well number—Number is assigned by 

Aquifer boundary

U.S. Geological Survey. Well data are in appendix at end of report

—Dotted line indicates where 

boundary was arbitrarily cut off 

Seismic-refraction survey line

Test-well site with groundwater sample collected(data in tables 1 and 2) !.

TM1008,TM1009

Test-boring site

TM2315

!.

Groundwater sample collected from well (data in tables 1 and 2) !.

TM1042
24 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

Figure 14. Aquifer types in lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York.

76°28' 76°26' 76°24'

42°24'

42°22'

42°20'

Base from U.S. Geological Survey, Seamless Data Distribution System, accessed in 2007 at http://seamless.usgs.gov 

Universal Transverse Mercator projection, Zone 18

0 1 2 MILES

0 1 2 KILOMETERS

EXPLANATION

Aquifer types

Confined only

Confined overlain by locally unconfined

Unconfined deltaic (overlying confined)

Unconfined headwater

Stratified-drift aquifer 

system boundary
Hydrology of the Stratified-Drift Aquifer System 25

Aquifer Types

The lower Sixmile Creek and Willseyville Creek 

trough contains unconfined and confined sand and gravel 

aquifers that overlie the bedrock aquifers throughout the 

trough (however, the bedrock aquifers are not the main focus 

of this report and are considered here as the base of the 

stratified-drift aquifer system). An unconfined aquifer has 

an upper surface (water table) that is open to the atmosphere 

through permeable material and in which the water level is 

free to rise and decline. Unconfined aquifers are typically 

closer to land surface than confined aquifers. In contrast, an 

unconsolidated confined aquifer (also known as an artesian 

aquifer) is a permeable deposit located between confining 

layers. Confining layers are made up of geologic material 

with lower permeability (low hydraulic conductivity) than the 

surrounding deposits that impedes the flow of groundwater. In 

this study area, the confining layers consist of till, or lacustrine 

very fine sand, silt, and clay. In a confined aquifer, the 

potentiometric surface is always above the top of the aquifer 

unit in which the water is stored. When a well is drilled into 

a confined aquifer, water in the well casing is forced up to 

its potentiometric surface, and if the pressure in the confined 

aquifer is great enough, it may cause the water in the well to 

flow above land surface, in which case the well is referred to 

as a flowing-artesian well. 

Aquifer Geometry

The aquifer geometry in the study area is complex 

as a result of glacial processes, previously deposited 

sediments that were eroded, or redeposition of sediment 

on top of older sediment, resulting in multiple sequences 

of unconsolidated deposits in the study area. Additionally, 

interglacial, interstadial, and post-glacial erosion modified 

the unconsolidated deposits—in some places, streams have 

cut gorges down to the bedrock floor of the trough breaching 

or entirely eroding the aquifers. Unconfined aquifers are 

present only locally, such as at the Brooktondale Delta in 

the central part and near the terminal moraine in the extreme 

southern part of the trough. In the study area, there is one 

continuous uppermost confined aquifer throughout the central 

and southern parts—one continuous basal-confined aquifer 

throughout the entire trough, and locally, only multiple 

intermediate confined aquifers such as in the central portion of 

the trough beneath the Brooktondale Delta. 

Sufficient well records were available to characterize 

some parts of the stratified drift in the trough, but there are 

also large areas where data were insufficient, such as in the 

southern part of the trough. More subsurface data are available 

for the shallower parts of the trough than the deeper parts 

because water-well drillers typically stop at the first major 

water-bearing unit that is penetrated. 

Unconfined Headwater Aquifer

Headwater aquifers typically are present in through 

valleys where drift forms a drainage divide (in this case the 

divide between the Susquehanna River Basin and the St. 

Lawrence River Basin shown in figure 3). Kame, alluvial, and 

a small amount of outwash sand and gravel deposits at the 

terminus of the Valley Heads Moraine in the southern part of 

the study area (figs. 2 and 5) form an unconfined headwater 

aquifer that begins at the southern boundary of Tompkins 

County and extends south into Tioga County (fig. 14). The 

part of the unconfined aquifer that is within Tompkins County 

is only 0.3 square mile (mi2) and consists mostly of coarsegrained sand and gravel in the upper part of the aquifer, but 

the total thickness is unknown. Drilling data indicate that the 

aquifer is at least 25 ft thick, based on (1) the record for a well 

(TM1260, 26 ft deep) sited along the edge of the trough, which 

shows that sand and gravel extends from 0 to 26 ft below 

land surface (with a reported yield of 4.5 gallons per minute 

(gal/min) and (2) visual inspection of a sand and gravel mine 

in Tioga County (0.6 mi south of the Tompkins and Tioga 

Counties border, fig. 5), which has been excavated into coarse 

sand and gravel to about 30 ft below land surface. However, 

results from a seismic-refraction survey in the southern part 

of the study area indicate that the unconsolidated deposits are 

more than 200 ft thick in the center of the trough. At other 

locations in central New York, the crest of the Valley Heads 

Moraine and the outwash in front of it contain large aquifers 

that are typically 80 to 140 ft thick (Miller, 2009; Miller and 

others, 1998; Kappel and Miller, 2003; Kappel and others, 

2001; and Randall and others, 1988). This condition may exist 

in this study area, too, but no wells are drilled deep enough to 

confirm this. 

Unconfined Deltaic Aquifer

The sand and gravel that comprises the delta near 

Brooktondale (figs. 5 and 9) forms a small unconfined aquifer 

(0.3 mi2 in area) in the central part of the study area. Although 

much of the upper part of the delta has been removed (up 

to 65 ft in places) by several aggregate mining operators, 

there remain sufficient amounts of sand and gravel in most 

places to form a thin aquifer that is relatively unused. The 

deltaic aquifer is wedge shaped and thickest near its apex near 

Brooktondale on the east side of the trough and thins radially 

to the west, north, and south as it fans out across the trough. 

The edge of the delta on the west side of the trough is at an 

altitude of about 1,010 ft, where it terminates by lapping onto 

till and kame moraine deposits (fig. 5). In 2008, the altitudes 

of land surface at the bottom of the aggregate mines ranged 

from 940 ft to 960 ft. 

Three well records (fig. 13, appendix 1) in the delta area 

were used to define the thickness and bottom of the deltaic 

aquifer. The well record for test well TM1008, (figs. 9 and 

13, appendix 1), drilled for this study in the bottom of one of 

the aggregate mines (altitude of land surface is 945 NVGD 
26 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

88), indicates that the well penetrated 24 ft of sand and gravel 

overlying clay (bottom of aquifer at altitude 920 ft NVGD 88) 

below the floor of the pit. Data from a commercial well 

(TM2128, figs. 9 and 13, appendix 1) drilled by an aggregatemining company and used for washing gravel indicate that 

there is at least 33 ft of sand and gravel below the floor of 

the pit, which puts the altitude of the bottom of the deltaic 

unconfined aquifer at less than 915 ft. At well TM2367 (figs. 8 

and 13, appendix 1) near the southern edge of the delta and 

outside of the gravel pit in an area that has not been mined, 

25 ft of sand and gravel remains that overlies a lacustrine silty 

sand unit, indicating that the bottom altitude of the unconfined 

deltaic aquifer is 953 ft. 

Confined and Locally Unconfined Aquifers 

The most areally extensive aquifers in the study area are 

confined sand and gravel aquifers, which are relatively thin 

compared to the till and glaciolacustrine clay, silt, and very 

fine sand that confine these aquifers throughout the lower 

Sixmile Creek and Willseyville Creek trough. As an exception, 

locally, such as in the Brooktondale delta area (fig. 9) and at 

the southernmost area of the trough where the Valley Heads 

Moraine is present, sand and gravel deposits are thicker and 

comprise a larger part of the stratified-drift sediments.

In the southern part of the study area, which has the 

lowest population density, there are few well data that could be 

used to characterize aquifers in the trough (fig. 7). However, 

it is reasonable to assume that there may exist at least a basal 

confined aquifer on top of bedrock similar to the central part 

of the trough (fig. 7) and similar to other glaciated valleys in 

central New York, but no wells are drilled deep enough in the 

southern part of the study area to confirm this. 

In the central part of the trough, there are typically two 

continuous and extensive confined aquifers (an upper confined 

aquifer and a basal confined aquifer) but locally there can be 

up to four confined aquifers. Wells that are along the sides of 

the trough (TM1671, TM2360, and TM2315; fig. 13) indicate 

there is likely only one confined aquifer along the flanks of the 

trough because these wells penetrated one sand and gravel unit 

and are likely finished close to bedrock, based on information 

extrapolated from surrounding wells. It isn’t until near Belle 

School Road that there is sufficient well data to characterize 

the aquifers in the central part of the study area. Well records 

for two adjacent wells along Belle School Road (TM1983 

and TM2005, fig. 13) in the central part of the trough indicate 

that there is at least one confined aquifer unit and possibly a 

second (basal confined aquifer) that hadn’t been penetrated 

by drilling. Well TM1983 (fig. 13) was cased to 220 ft and 

finished in a sand unit that heaved up the casing 40 ft, causing 

the well to be abandoned. Nearby, well TM2005 (fig. 13) 

was drilled to a depth of 30 ft and finished in sand and gravel 

underlying till (bottom of till at 27 ft). 

In the central part of the study area, south of the 

Brooktondale Delta, well records indicate that there are at least 

two continuous confined aquifers in the central part of the 

trough (fig. 8). Wells TM 50, TM 51, TM 588, and TM1698, 

(figs. 8 and 13) are finished in a confined aquifer 90 to 105 

ft below land surface and are either flowing artesian or have 

water levels 2 to 3 ft below land surface. Wells TM2367 and 

TM1019 (figs. 8 and 13), 207 and 304 ft deep, respectively, 

are finished in confined sand and gravel units that are likely 

on top, or close to, bedrock, based on seismic refraction data 

nearby. The depth to water in well TM2367 was 40 ft (altitude 

water level was 938 ft) on May 21, 2007, which is several 

tens of feet lower than levels of wells finished in the upper 

confined aquifer that were either under flowing conditions 

or had water levels several feet deep (altitudes ranging from 

968 to greater than 975 ft). Well TM1019 is the deepest well 

(304 ft) in the study area that is in a sand and gravel aquifer.

Underlying the unconfined deltaic aquifer near 

Brooktondale in the central part of the study area are four 

confined sand and gravel aquifers (fig. 9). The uppermost 

confined aquifer (fig. 9) probably correlates to the continuous 

upper confined aquifer found at depths 90 to 105 ft in 

geohydrologic section B—B ́ (fig. 8). Test well TM1008 

(figs. 9 and 15) was drilled to a depth 187 ft and finished in 

a continuous, basal confined sand and gravel aquifer that 

directly overlies bedrock. Test well TM1009 was drilled to 

a depth 130 ft, and the casing was perforated from 122 to 

126 ft. It is finished in one of the discontinuous confined 

sand and gravel aquifers in the middle section of the trough 

(figs. 9 and 15). Water levels differed by 4 to 5 ft in test wells 

TM1008 and TM1009 (fig. 15), indicating that the confining 

unit between the aquifers impedes groundwater movement 

between the two aquifers. The relatively large amounts of 

sand and gravel that form the confined aquifers that underlie 

the Brooktondale Delta make this area potentially one of the 

most favorable parts of the study area for large amounts of 

groundwater withdrawal.

About 0.6 mi north of the Brooktondale delta (fig. 13), 

wells TM 65, TM1309, and TM1503 in the western part of 

the valley were drilled deeper (from 94 to 197 ft) than wells 

TM 550, TM 551, and TM1532 in the lower Sixmile Creek 

floodplain in the eastern part of the trough (from 70 to 95 ft). 

Wells TM 544 and TM 552, on a terrace 50 to 60 ft higher in 

altitude than the floodplain in the eastern part of the trough, 

were finished in a confined sand and gravel unit 163 and 

180 ft deep, respectively. These well records suggest that 

there are two confined sand and gravel aquifers in most places 

in the eastern part of the trough but probably only one deep 

confined aquifer in the western part. Two of the deep wells in 

the western part of the trough (TM1503 and TM1309) were 

finished in sandy deposits. In the eastern part of the trough, 

well TM1532 (fig. 13) was drilled to a depth of 95 ft and 

had the largest reported yield (greater than 50 gal/min) for a 

domestic well in the study area. 

The farthest north in the trough that domestic wells tap 

the upper confined sand and gravel aquifer is near German 

Crossroad (figs. 11 and 13). From German Crossroad to the 

north, Sixmile Creek and other streams have removed large 

amounts of the upper unconsolidated deposits, some of which 
Hydrology of the Stratified-Drift Aquifer System 27

Figure 15. Well log and construction details of USGS test wells TM1008 and TM1009, Perkins Road, Town of Caroline, New York.

Altitude relative

to NVGD 29

Coarse sand and gravel, fine to coarse pebbles, 

fine to coarse sand, subround to round clasts, 

contains water,water level is 6 feet (confined aquifer)

Coarse sand and gravel, fine to coarse pebbles, 

fine to coarse sand, produces 30 gallons per minute

Developed well TM1008 for 0.5 hour at rate of 20 gallons per minute.

Developed well TM1009 for 1.0 hour at rate of 30 gallons per minute.

Shale, dark grey, makes little or no water

923

947

882

897

847

790

773

751

747

825

814

809

911

923

947

882

897

847

790

773

751

747

825

814

Sand and gravel, brown, subround-round pebbles

(unconfined aquifer)

Clay, grey

0

DEPTH BELOW LAND SURFACE, IN FEET

36

24

65

50

100

 122

 133

 138

157

174

200

196

Altitude of land surface is 946.6 feet 

 above NVGD 29

Water level 

= 1.3 feet 

above land 

surface, 

1/3/2007

Altitude of 

Water Level = 

947.82 feet

Water flowing 

above top of

casing, 

1/3/2007

Altitude of 

Water Level = 

>952 feet

Water from sand

and gravel aquifer 

enters open-end 

6-inch casing at 187 feet

U. S. Geological Survey test wells TM1008 and TM1009

Town of Caroline gravel pit, Perkins Road, Town of Caroline, NY

Site name: TM1009 (well depth = 130 feet)

Site identifier: 422236076240402

Latitude: 42o

22' 35.77''

Longitude: 076o

24' 03.52''

Date completed: 12/12/2006

6-inch-diameter steel casing

Casing above ground = 5.3 feet

Site name: TM1008 (well depth = 187 feet)

Site identifier: 422236076240401

Latitude: 42o

22' 35.80''

Longitude: 076o

24' 03.50''

Date completed: 12/12/2006

6-inch-diameter steel casing

Casing above ground = 5.2 feet

TM1008

Altitude of top of 

six-inch casing

= 951.76 feet

TM1009

Altitude of top of 

six-inch casing

= 951.92 feet

Latitude and longitude measurement made by GPS (NAD83)

Drilling contractor: Randolph Drilling, McLean, N.Y.

Sand

Clay, grey, soft

Till, grey, stony, with silt matrix

Fine sand, heaves up casing

Till, grey, stones embedded in sand and silt matrix

809

Coarse sand and gravel, fine to coarse pebbles, fine 

to coarse sand, subround-round clasts, produces

20 gallons per minute (confined aquifer)

Coarse sand and gravel, fine to coarse pebbles, 

fine to coarse sand, subround-round clasts

(confined aquifer) 

Water from sand

and gravel aquifer 

enters perforations 

between 122–126 feet

and bottom of

casing at 130 feet

Bottom of

casing = 187 feet

Artesian

flow

Bottom of hole at -200 feet

911
28 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

may have included aquifer material (figs. 10 and 11). Wells 

TM1002 and TM 62 (88 and 172 ft deep, respectively) are 

finished in the basal confined aquifer on top of the inner 

glacial U-shaped trough (fig. 10). A buried bedrock gorge 

(likely an extension of the interglacial “600 ft buried gorge”) 

was detected using seismic-refraction surveys in the central 

part of the trough (fig. 10).

North of the Silt Dam, Near Burns Road (fig.13), Sixmile 

Creek has incised through all of the valley fill and is at or 

near bedrock that forms the bottom of the inner glacial trough 

except in areas where the “600 ft buried gorge” underlies the 

trough north of the Silt Dam (fig. 11). From this area and to 

the north, Sixmile Creek and some major tributaries have fully 

penetrated the valley fill and sand and gravel aquifers that 

are exposed in the remaining bluffs, allowing groundwater to 

discharge from the aquifers. These exposed sand and gravel 

aquifers may not be viable as a year-round water resource 

because they may be marginally, or only seasonally, saturated. 

North of the Silt Dam and underlying the Ithaca 

Reservoir the only major sand and gravel aquifer remaining 

is within the interglacial “600 ft buried gorge”. North of the 

northern end of Ithaca Reservoir, Sixmile Creek has reentered 

the interglacial “600 ft buried gorge” and has eroded most of 

the unconsolidated deposits that previously filled the gorge. 

Presently (2010) the stream is restricted by the bedrock floor 

and walls of the gorge. The absence of all unconsolidated 

deposits from the gorge just downstream from the Ithaca 

Reservoir marks the northern boundary of the sand and gravel 

aquifers in the trough (figs. 4 and 14). 

Bedrock Aquifers

While the focus of this study is not on water derived 

from bedrock, bedrock aquifers are important water sources 

in the region because they underlie the entire area. Yields 

available from individual wells completed in bedrock are 

generally much less than yields from wells in sand and gravel. 

In most cases, bedrock aquifers are the only source of water 

in the uplands. The lower Sixmile Creek Basin is underlain by 

Devonian-age sedimentary rocks consisting mostly of shales 

and siltstones. Water movement is controlled by secondary 

permeability in the joints or fractures in the rock and typically 

predominates along bedding planes in sedimentary bedrock. 

The density, width of opening, and connectivity of waterbearing fractures decrease with depth due to the diminishing 

effects of weathering and the increasing weight of overlying 

rock with increasing depth that result in fewer, less-open, 

and less-connected fractures. Therefore, most water that is 

available to wells is generally in the upper 200 ft of bedrock; 

however, there is indication that, in some areas, salty water 

is present in the bedrock (TM2717, appendix 1). Therefore, 

water from the bedrock may not be potable in certain places. 

In the lower Sixmile Creek and Willseyville Creek Basins, 

well yields typically range from 2 to 5 gal/min, but in some 

wells yields are less than 1 gal/min and others yield up to 

30 gal/min.

Groundwater Levels and Flowpaths

Natural changes in aquifer storage, exhibited by 

fluctuations in groundwater levels, generally follow seasonal 

patterns in the study area. Changes in aquifer storage between 

any two points in time are calculated as the difference in 

water levels between the two times multiplied by the storage 

coefficient. For unconfined aquifers, gravity drainage and 

filling of pores is the dominant mechanism for storage change, 

and generally the storage coefficient (specific yield) ranges 

from about 0.02 for fine-grained sediments to 0.35 for very 

coarse-grained sediments (Freeze and Cherry, 1979). Storage 

changes for confined aquifers are dominated by water and 

sediment compression and expansion, and storage coefficient 

values are much less. Storage coefficients reported for 

confined stratified-drift aquifers in the glaciated Northeast 

range from 10-2 to 10-4 (Kontis and others, 2004; Crain, 1966; 

and Randall, 1979). Values of storage coefficient are best 

determined with aquifer tests that affect a fairly large part of 

the aquifer. 

Changes in storage in an aquifer include short, relatively 

well-defined periods of increased storage in the spring and late 

fall, when recharge to the aquifer exceeds discharge from the 

aquifer, and longer periods of decreased storage in the summer 

and winter, when discharge generally exceeds recharge. Also, 

a regional drought that reduces recharge over a large area over 

multiple seasons can result in reduced storage and yield from 

sand and gravel aquifers.

A generalized depiction of the water table in the 

unconfined aquifer (Brooktondale delta) is shown in 

figure 16 and was constructed using water-level measurements 

made during this investigation from 2005 to 2007 and from 

locations of springs at the lower flanks of bluffs along the 

north and west margins of the delta. Groundwater flows 

roughly perpendicular to water-table contours in unconfined 

aquifers or to potentiometric-surface contours in confined 

aquifers. Groundwater in the southern part of the unconfined 

aquifer flows to the west and discharges into Beaver Creek. 

Groundwater in the northern part of the unconfined aquifer 

flows to the northwest where some of the groundwater 

discharges to springs along the northern margin of the delta 

ending up in downstream reaches of Sixmile Creek while 

some groundwater discharges to springs along the western 

margin of the delta and flows into Beaver Creek. 

Groundwater in the uppermost confined aquifer in the 

trough flows predominantly to the north from the surfacewater divide that separates drainage that flows northward 

into the St. Lawrence River Basin and southward into 

the Susquehanna River Basin (fig. 17). Just north of the 

surface-water divide in the southern part of the study area, 

groundwater in the morainal deposits in the western side of 

the trough initially flows eastward from the west valley wall 

to the center of the valley where it changes course and flows 

northward (fig. 17). Direction of groundwater flow to the south 

of the surface-water divide is unknown because of lack of 

water-level data. 
Hydrology of the Stratified-Drift Aquifer System 29

Figure 16. Water table in the unconfined aquifer (Brooktondale Delta) in lower Sixmile Creek and Willseyville 

Creek trough, Tompkins County, New York.

76°24'30" 76°24'

42°23'

42°22'30"

0 1,000 2,000 FEET

0 250 500 METERS

930

940

950

920

910

900

890

880

930

938

940

Base from U.S. Geological Survey, Seamless Data Distribution System,

accessed in 2008 at http://seamless.usgs.gov/

Universal Transverse Mercator projection, Zone 18

938

930 Generalized water-table altitude—Shows approximate altitude of the water level in the unconfined aquifer near 

Brooktondale derived from measurements made from 2005 to 2007, from historic data over several decades and 

during all seasons, and from stream- and river-surface altitudes as indicated on 1:24,000-scale topographic 

maps; therefore, the contours are an approximation and reflect a generalized conception of the water-table in this 

area. Contour interval 10 feet. Datum is National Geodetic Vertical Datum of 1929

Boundary of unconfined aquifer—Approximate boundary of the unconfined aquifer Brooktondale Delta area 

Direction of groundwater flow—Blue arrows show direction of flow in unconfined aquifer

Boundary of confined aquifer—Approximate boundary of the confined aquifer 

Well with water-level measurement—Blue number is altitude of water level in the unconfined aquifer

EXPLANATION
30 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

76°24' 76°26' 76°28'

42°24'42°22'

880

900

860

920

840

940

980

960

1,000

990

880

900

860

920

840

940

980

960

1,000

990

Upper confined

aquifer may

be absent

Banks 

?

?

?

Road

D

D

D

D

D

D

D

D

D

D

D

871 850+ (flows)

870+ (flows)

969 968

867

1,005

995 1,008

1014

1001
Hydrology of the Stratified-Drift Aquifer System 31Figure 17. Potentiometric surface in the upper confined aquifer in lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York.

42°22'

42°20'

0 1 2 MILES

0 1 2 KILOMETERS

992

1050

Aquifer boundary—Approximate boundary of stratified-drift aquifer (dashed where arbitrarily cut off)Direction of groundwater flow—Blue arrows show direction of flow in upper confined aquifer

850+

Surface-water divide (and approximation of groundwater divide)—Drainage divide between water draining to the Lake Ontario Basin to the north, and water draining to the Susquehanna River Basin to the southNon-flowing artesian well with water-level measurement—Number is altitude of water level in the upper confined aquiferFlowing artesian well measurement

EXPLANATION

—Number is minimum altitude of water level

DD

Generalized potentiometric surface contour—Shows approximate altitude of the potentiometric surface in the upper confined aquifer derived from measurements made from 2000 to 2008, from historic data over several decades and during all seasons, and from stream- and river-surface altitudes as indicated on 1:24,000-scale topographic maps; therefore, the contours are an approximation and reflect a generalized conception of the potentiometric surface in this area. Contour interval is variable feet. Datum is National Geodetic Vertical Datum of 1929

Base from U.S. Geological Survey, Seamless Data Distribution System,accessed in 2008 at http://seamless.usgs.gov/Universal Transverse Mercator projection, Zone 18

990

1,000

1,000

990

990

1,000

1,000

990

Insufficient 

data

D

D

D

D

D

D

D

D

D

D

969 968

990

992

1,005

995 1,008

1,009

1001

1,020
32 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

The groundwater in the uppermost confined aquifer is 

artesian in most places and flowing artesian in some low areas 

in the trough. However, in some places along the margins of 

the trough walls where the confined aquifer and the associated 

confining unit lap up higher on the valley walls, the water 

level is below the bottom of the confining unit (till), and a 

small portion of the aquifer is unconfined. In areas above 

altitude of 1,050 ft, such as along the margins of the trough, 

the depth to water in wells finished in the upper confined 

aquifer is as much as 95 ft below land surface. In low-lying 

areas, the depth to water is either only several feet below land 

surface or above land surface (flowing artesian conditions). 

North of Banks Road (fig. 17), the uppermost confined aquifer, 

which is composed of kame deposits of the Valley Heads 

Moraine, is absent because these deposits pinch out.

Groundwater-flow patterns in the basal confined aquifer 

are similar to those in the uppermost confined aquifer although 

water levels in some areas can differ greatly. Groundwater 

in the basal confined aquifer flows predominantly northward 

from the surface-water divide (fig. 18). Just north of the 

surface-water divide, groundwater in the morainal deposits on 

the western side of the trough initially flows eastward from the 

west valley wall to the center of the valley turning northward 

in the central part of the aquifer and northwestward in the 

northern part of the aquifer (fig. 18). Groundwater eventually 

discharges to lower Sixmile Creek and to the Ithaca Reservoir 

near the northern terminus of the basal confined aquifer 

(fig. 18).

Most wells in the basal confined aquifer in low-lying 

areas are under flowing-artesian conditions with hydraulic 

heads 10 to 40 ft above land surface, such as well TM1002. 

However, wells in areas that are located 50 to 100 ft above 

the floodplain, such as on terraces and kames along the 

trough walls, have heads that are below land surface and do 

not flow, for example well TM2367. The existence of a basal 

confined aquifer in the Willseyville Creek part of the trough is 

unverifiable because of a lack of detailed well data; however, 

it is likely that one exists based on the fact that basal aquifers 

that extend throughout entire valleys are common in other 

major troughs in central New York. 

In some areas, multiple confined aquifers are present in 

the trough, such as at the Town of Caroline sand and gravel 

pit about 0.5 mi west of Brooktondale (fig. 9). At the bottom 

of the pit, a nested pair of test wells were drilled (fig. 13). 

Well TM1008 (well depth 187 ft) was finished in the basal 

confined aquifer and well TM1009 (well depth 130 ft) was 

finished in one of the intermediate-depth, confined sand and 

gravel aquifers (figs. 9 and 15). Bedrock was penetrated at 

196 ft. Water levels were measured in the wells from January 

1, 2007, to February 11, 2009, to determine the head relations 

between the two aquifers units (fig. 19). Heads were found to 

be consistently 4 to 5 ft higher in well TM1009 (finished in a 

shallower confined aquifer) than in well TM1008 (finished in 

a deeper confined aquifer), which indicates that the vertical 

component of the hydraulic gradient is downward in this area. 

Heads in both wells were above land surface in the bottom of 

the sand and gravel pit in which they were drilled.The similar 

water-level trends and consistent magnitude of head changes 

between the two aquifers, shown in the hydrograph in figure 

19, suggest that the aquifers may have the same recharge area 

and are somewhat hydraulically connected.

Sources of Recharge 

The amount of recharge to stratified-drift aquifers is a 

key determinant of the long-term availability of water. More 

recharge is available to unconfined aquifers than to confined 

aquifers. In general, there are a number of sources of recharge 

to stratified-drift aquifers (fig. 20). Four principal sources 

are: (1) direct infiltration of precipitation (rain and snow 

melt) where the aquifer crops out at land surface, (2) surface 

runoff and subsurface flow from adjacent unchanneled upland 

areas, (3) leakage from tributary streams where flow is over an 

unconfined aquifer, and (4) upward leakage from the bedrock 

and leakage from adjacent fine-grained confining units, 

especially during pumping. Sources of recharge to the aquifers 

in the lower Sixmile Creek and Willseyville Creek trough vary 

from place to place, and in some areas they are unknown as 

a result of the complex geohydrologic conditions present in 

the study area.Three distinct hydrologic settings that receive 

recharge are present in the study area (fig. 20)—the isolated 

basal aquifer, the unconfined delta and confined aquifers, and 

confined aquifers, which correspond to the northern, central, 

and southern parts of the trough respectively.

Unconfined Aquifers

The major sources of recharge to the unconfined 

aquifers (Brooktondale Delta in the central part and the 

headwater aquifer at the crest of the Valley Heads Moraine 

in the southern part of the study area) in the lower Sixmile 

Creek and Willseyville Creek trough are (1) direct infiltration 

of precipitation where water moves predominantly in a 

downward direction through the unsaturated zone toward the 

water table and (2) unchanneled surface runoff and subsurface 

inflow from adjacent upland areas that seep into the aquifer 

along the trough walls (figs. 20B and 20C). Over areas of 

sand and gravel, runoff is generally negligible so that all 

precipitation that is not lost to evapotranspiration recharges 

the unconfined aquifer. Unchanneled upland runoff typically 

contributes about 18 to 23 percent of the total recharge to 

unconfined stratified-drift aquifers in central New York (Miller 

and others, 1998; Kontis and others, 2004; Miller and others, 

2008). Seepage losses from upland tributary streams comprise 

a relatively small amount of recharge to the aquifers in this 

study area because (1) the area of unconfined aquifers is small 

(most of the major aquifers are confined), (2) no streams cross 

the Brooktondale Delta (an unconfined aquifer), and (3) the 

area where confined aquifers crop out at land surface along the 

trough walls is relatively small. 
Hydrology of the Stratified-Drift Aquifer System 33

Confined Aquifers

The major sources of recharge to the confined aquifers 

in the southern part of the study area are (1) direct infiltration 

of precipitation where confined aquifers crop out at land 

surface—mostly along the west trough wall and to a lesser 

degree along the east trough wall; (2) unchanneled surface and 

subsurface runoff from adjacent upland areas that seeps into 

the aquifer along the west trough walls; (3) subsurface inflow 

from underlying till or bedrock at the lateral contacts at trough 

walls, (4) adjacent fine-grained stratified drift, especially when 

the aquifer is pumped; and (5) bedrock at the bottom of the 

trough (fig. 20C). 

Wells finished in the kame moraine along the western 

margin of the trough in the central part of the stratified-drift 

aquifer area have water levels several tens of feet higher in 

altitude than wells finished in the confined aquifers in the 

middle of the trough. This hydraulic-head relation is consistent 

with the concept that recharge from unchanneled runoff from 

adjacent hillsides and smaller amounts from precipitation and 

discharge from streams is entering the aquifers along the west 

trough wall (figs. 17 and 18). Due to relatively small amounts 

of kame moraine deposits along the eastern part of the trough 

(fig. 5), there is less recharge from that side of the trough. 

Little or no recharge from surface sources occurs in the middle 

of the trough because fine-grained deposits (till and lacustrine 

fine sand, silt, and clay) crop out at, or near, land surface, 

impeding movement of water into the confined aquifers 

(fig. 20C).

In the northern part of the study area (fig. 4), the basal 

confined aquifer is completely surrounded by confining units 

and is isolated (fig. 20A) from major sources of recharge 

such as (1) precipitation that falls directly over the valley, 

(2) streams flowing across the valley, and (3) runoff from 

adjacent hillsides. Therefore, the amount of recharge to the 

confined aquifer in this area is relatively small. In general, 

relatively little recharge may occur through subsurface flow 

from the bedrock and from overlying fine-grained sediments 

(fig. 20A).

The hydrograph depicted in figure 19 shows the period 

when the confined aquifers in the central part of the study are 

recharged. The recharge period (when groundwater storage 

in the aquifer is increasing) is represented when groundwater 

levels are rising, which occurs mostly during late fall, winter, 

and early spring, particularly just before and just after the 

growing season (fig. 19). Little recharge occurs during the 

growing season from late spring to early fall when the rate of 

evapotranspiration typically exceeds the rate of precipitation. 

Groundwater Discharge 

In the northern and central extents of the stratified-drift 

aquifer (fig. 4), most groundwater ultimately discharges 

into lower Sixmile Creek. Lesser amounts of groundwater 

discharge to pumping wells. Transpiration limits recharge 

when water vapor escapes from living vegetation back into the 

atmosphere, and in some cases even induces discharge directly 

from the aquifer where roots extend below the water table 

mostly during the spring when the ground can be saturated 

and close to, or at, land surface. In the southeastern part of 

Tompkins County, evapotranspiration is estimated to range 

between 19 to 20 inches per year or roughly half of the annual 

precipitation in this area (Kontis and others, 2004, plate 1). 

Due to lack of well and water-level data in the southern part of 

the study area, the groundwater flow patterns and location of 

groundwater discharge are unknown.

Unconfined Aquifer at the Brooktondale Delta

Most of the recharge from precipitation directly over the 

delta and from runoff from adjacent hillsides on the east side 

of the trough enters the unconfined aquifer at the Brooktondale 

Delta and flows westward and northwestward discharging 

at springs along the western and northern edges of the delta 

(fig. 16). Groundwater in the southern part of the deltaic 

aquifer flows to the west and discharges into Beaver Creek. 

Groundwater in the northern part of the deltaic aquifer flows 

to the northwest where some of the groundwater discharges 

via springs along the northern margin of the delta to Sixmile 

Creek, and some discharges to springs along the western 

margin of the delta and then to Beaver Creek. Groundwater 

also discharges to ponds that have been created where gravel 

mining has extended below the water table. Groundwater is 

also withdrawn for washing the aggregate at the gravel pits, 

but there is little consumptive loss of water because most of 

the water is allowed to return to the aquifer. 

Confined Aquifers

In the northern and central extents of the stratified-drift 

aquifer of the study area, groundwater in the confined aquifers 

discharges mostly to Sixmile Creek, to the Ithaca Reservoir, 

and to pumped wells. Since the confined aquifers are at depths 

greater than 10 ft below land surface, there is negligible loss 

through evapotranspiration. 

Groundwater in the basal confined aquifer flows 

predominantly north and northwestward and discharges to 

Sixmile Creek and to the Ithaca Reservoir. At the Ithaca 

Reservoir, Sixmile Creek has down cut and removed the layer 

that confines the basal aquifer, allowing water from the basal 

aquifer to discharge directly into Sixmile Creek and the Ithaca 

Reservoir. North of the Ithaca Reservoir, Sixmile Creek has 

fully penetrated the valley-fill in both the U-shaped valley and 

in the interglacial gorge (fig. 12) and the aquifer is absent. 

Groundwater in the upper confined aquifer also 

discharges to Sixmile Creek. The northern extent of the upper 

confined aquifer ends near Banks Road (fig. 17) where the 

aquifer pinches out at depth or where it has been penetrated by 

Sixmile Creek. 
34 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

76°24' 76°26' 76°28'

42°24'42°22'

 (Groundwater discharges from basal confined aquifer to Ithaca Reservoir)

990

980

960

900

940

880

920

1,000

860

840

800

780

820

760

740

990

980

960

900

940

880

920

1,000

860

840

800

780

820

760

740

874

976+

(flows)

870+

(flows)

990

839

817

836

1,008

1,014

1,005

827.4

947.56

797.18
Hydrology of the Stratified-Drift Aquifer System 35Figure 18. Potentiometric surface in the basal confined aquifer in lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York.

42°22'

42°20'

0 1 2 MILES

0 1 2 KILOMETERS

1050 EXPLANATION

992

1050

Aquifer boundary—Approximate boundary of stratified drift aquifer (dashed where arbitrarily cut off)Direction of groundwater flow—Blue arrows show direction of flow in basal confined aquifer

850+

 (flows)

Surface-water divide (and approximation of groundwater divide)—Drainage divide betweenwater draining to the Lake Ontario Basin to the north, and water draining to the Susquehanna River Basin to the southNon-flowing artesian well with water-level measurement—Number is altitude of water level in the basal confined aquiferFlowing artesian well—Number is minimum altitude of water levelGeneralized potentiometric surface contour—Shows approximate altitude of the potentiometric surface in the basal confined aquifer derived from measurements made from 2000 to 2008, from historic data over several decades and during all seasons, and from stream- and river-surface altitudes as indicated on 1:24,000-scale topographic maps; therefore, the contours are an approximation and reflect a generalized conception of the potentiometric surface in this area. Contour interval is variable feet. Datum is National Geodetic Vertical Datum of 1929

Insufficient 

data

990

980

1,000

990

980

1,000

990

992

1,008

1,009

1,005

Base from U.S. Geological Survey, Seamless Data Distribution System,accessed in 2008 at http://seamless.usgs.gov/Universal Transverse Mercator projection, Zone 18
36 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

Figure 19. Hydrograph showing altitude of groundwater levels from January 1, 2007 to February 11, 2009 in test wells TM1008 

and TM1009 at Town of Caroline sand and gravel pit, Perkins Road, Brooktondale, New York.

The base-flow and storm-runoff components (fig. 21) of 

total streamflow at Sixmile Creek at Brooktondale streamgage 

station (upper Sixmile Creek Basin) and at Sixmile Creek at 

Bethel Grove streamgage station (lower Sixmile Creek Basin,) 

(fig. 3) were calculated by using a hydrograph-separation, 

computer program HYSEP (Sloto and Crouse, 1996) and 

continuous discharge data for 2003–07. HYSEP calculates 

base flow as a percentage of total mean annual flow. The two 

Sixmile Creek streamgage stations meet the recommended 

requirements for using the HYSEP program because they are 

not regulated by dams or flood-control reservoirs upstream, 

which could cause a decrease in stormflow and an increase 

in base flow after a storm. These streamflow records span 

a relatively short period (5 years); therefore, the accuracy 

of these estimates is not as great as would be with at least 

30 years of record.

Results of the hydrograph-separation analyses for 

2003–07 indicate that base flow constitutes about 64 and 

56 percent of total annual discharge at Sixmile Creek at 

Brooktondale and Sixmile Creek at Bethel Grove, respectively 

(fig. 21). The results of the hydrograph-separation analyses 

indicate that the flow past Brooktondale has a greater 

component that is base flow (groundwater) than at Bethel 

Grove, which suggests that greater amounts of groundwater 

discharge to streams from aquifers in the upper Sixmile Creek 

valley than in the lower Sixmile Creek valley. 

The greater percentage of base flow in the upper part 

compared to the lower part of Sixmile Creek Basin is due 

to several factors. First, at the Brooktondale streamgage 

station, the stream has eroded and fully penetrated the 

valley fill deposits, including the aquifers, resulting in little 

or no groundwater underflow past the streamgage because 

the groundwater in the stratified-drift deposits is forced to 

discharge to the stream at this point. At the Bethel Grove 

streamgage station, the stream has only partially penetrated 

the stratified-drift deposits, allowing a significant portion 

of the groundwater to flow beneath the streamgage station 

as underflow mostly through the basal confined aquifer and 

2007 2008

944

946

948

950

952

954

956

958

J F M A M J J A S O N D J F M A M J J A S O N D J F

No

data

Well TM1009 (depth = 130 ft)

 Well TM1008 (depth = 187 ft)

Land surface

ALTITUDE OF WATER LEVEL, IN FEET ABOVE NVGD 1929
Hydrology of the Stratified-Drift Aquifer System 37

Figure 20. Sources of recharge in aquifers A, the northern part of the lower Sixmile Creek and Willseyville Creek trough, 

B, the central part, and C, the southern part, Tompkins County, New York.

C Southern part of study area—confined aquifers

4

B Central part of study area—unconfined and confined aquifers

A Northern part of study area—isolated basal aquifer

2 1

2

2

1

1

4

8

7

7

9

1

Some water may recharge the buried aquifer as 

subsurface flow from adjacent fine-grained sediments, 

especially when the aquifer is pumped.

Lateral contact between fine-grained stratified drift 

and till or bedrock. Flow across this contact is small. 

Some water may recharge the buried aquifer as 

subsurface flow from underlying till or bedrock.

Little or no water recharges the buried aquifer from 

streams flowing across the fine-grained deposits in 

the main valley. 

Precipitation on surficial alluvial fan, kame moraine, 

and deltaic deposits. 

Drainage divide: a boundary between adjacent 

drainage basins. Groundwater and surface water 

divides in uplands are coincident.

3

6

6

6

5

6

7

8

9

Some water may recharge the buried aquifer from 

precipitation where the sand and gravel aquifer 

crops out at land surface along the edges of the 

valley.

3

4

5

5

5

4

8

9

EXPLANATION

Shale and siltstone

Till

Fine-grained sediments (lacustrine

fine sand, silt and clay; and till)

Sand and gravel

Deltaic sand, pebbly sand and gravel

LITHOLOGY

Hatched where aquifer is confined by an 

overlying confining unit.

Some subsurface flow and unchanneled runoff from 

upland areas recharge deltaic deposits that then may 

recharge the buried aquifer. 

7

2 Edge of valley-fill deposits.

3
38 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

to enter the stream further down valley where the channel 

has fully penetrated the stratified-drift deposits and flows on 

bedrock in the “600 ft gorge.” Second, the volume of surficial 

sand and gravel is greater in upper Sixmile Creek Basin than 

in lower Sixmile Creek Basin, allowing more groundwater to 

be transmitted through the aquifers to the stream in the upper 

part of the basin. Because the presence of surficial sand and 

gravel deposits reduces rapid runoff, precipitation is stored as 

groundwater that is gradually released to streams. In valleys 

with relatively large amounts of surficial sand and gravel, there 

is proportionally more infiltration of precipitation and storage 

capacity; therefore, more groundwater discharges to streams 

than in valleys that contain mostly till and lacustrine deposits, 

which have poor infiltration capacity and rapid runoff.

Pumping Withdrawals

Most groundwater withdrawals from confined sand and 

gravel aquifers in the lower Sixmile Creek and Willseyville 

Creek trough are from open-ended, 6-inch (in.) diameter 

domestic wells, with other minor amounts from farm and 

commercial wells that tap the confined aquifers. No large 

municipal pumping wells are in the study area. Some 

groundwater is withdrawn seasonally from the unconfined 

aquifer (Brooktondale Delta) by an aggregate-mining 

operation for washing purposes. Domestic water use is water 

used for indoor and outdoor household purposes. In lower 

Sixmile Creek and Willseyville Creek trough an estimated 

600 people rely solely on groundwater from the stratified-drift 

aquifer system. Homeowner wells that were just within the 

areal extent of the aquifer’s boundaries, but were finished in 

bedrock, were not included as users of the sand and gravel 

aquifers. Additionally, water is used by non-permanent 

residents such as staff at commercial facilities. The estimated 

total groundwater use for human consumption is estimated 

to be about 45,000 gal/d or 0.07 cubic feet per second (ft3/s) 

based on an average water use of 75 gal/d per person for selfsupplied water systems in New York (Hutson and others, 2000, 

table 6) times the estimated 600 people that pump from the 

stratified-drift aquifers. However, unknown quantities of water 

are also withdrawn from wells in the stratified-drift aquifers 

from (1) several small crop farms, (2) an unknown number of 

flowing artesian wells that continually discharge water from 

the aquifer, and (3) about six small commercial facilities.

Figure 21. Graphs showing results of hydrograph separation analyses for Sixmile Creek at Brooktondale (upper 

Sixmile Creek Basin) and Sixmile Creek at Bethel Grove streamgages (lower Sixmile Creek Basin) for the period 

2002–07. Locations of streamgages are shown in figure 3.

Sixmile Creek at Brooktondale

(upper Sixmile Creek Basin)

Sixmile Creek at Bethel Grove

(lower Sixmile Creek Basin)

64 percent base flow

(groundwater)

36 percent 

storm runoff

56 percent base flow

(groundwater)

44 percent 

storm runoff
Groundwater Quality 39

Groundwater Quality

Because all drinking water is derived solely from the 

confined aquifers, water-quality samples were collected only 

from those wells. Water samples were collected from six wells 

— two test wells (TM1008 and TM1009) and four private 

residential wells (TM1002, TM1503, TM1532, and TM2355) 

from December 2006 through August 2007 to characterize the 

chemical quality of groundwater. Field measurements were 

made for pH, specific conductance, and water temperature. 

The concentrations of 42 constituents that included nutrients, 

major inorganic ions, and trace elements were determined 

by the USGS National Water Quality Laboratory (NWQL) 

in Denver, Colorado. Wells that were sampled are shown 

in figure 13. Analytical results for selected constituents 

are compared with Federal drinking-water standards. The 

standards include Maximum Contaminant Levels (MCLs), 

Secondary Maximum Contaminant Levels (SMCLs), and 

Health Advisories (HAs) established by the USEPA (2006).

Physical Properties

Wells that were sampled ranged from 88 to 197 ft deep. 

The pH of the samples (table 2) ranged from 7.6 to 8.1; no pH 

measurement was outside the accepted SMCL range of 6.5 to 

8.5. Specific conductances of the samples ranged from 291 to 

492 microsiemens per centimeter (μS/cm) (table 2).

Major Inorganic Ions

The cation that was detected in the greatest concentration 

was calcium, ranging from 30.5 to 63.6 mg/L (table 2). 

Sodium values ranged from 9.47 to 28.8 mg/L. No samples 

exceeded the USEPA Drinking Water Health Advisory (HA) 

for sodium, which recommends sodium concentrations in 

drinking water do not exceed 60 mg/L on the basis of taste. 

This health advisory is intended as a guideline for users. 

Silica values ranged from 7.46 to 13.2 mg/L. Calcium and 

magnesium contribute to water hardness and one of the six 

sampled wells yielded water with a hardness greater than 

180 mg/L, which is classified as “very hard” (Hem, 1985).

The anion that was detected in the greatest concentration 

was bicarbonate, while chloride and sulfate were detected 

in generally lesser concentrations. Bicarbonate (as CaCO3) 

ranged from 173 to 199 mg/L (table 2). Bicarbonate values 

were calculated from the alkalinity concentrations, which are 

given in milligrams per liter of CaCO3. Chloride values ranged 

from 0.67 to 35.6 mg/L, not exceeding the SMCL of 250 mg/L 

(table 3). Sulfate values ranged from 8.08 to 47.1 mg/L and 

did not exceed the SMCL of 250 mg/L.

Nutrients

Groundwater samples were analyzed for several nitrogen 

and phosphorous species (table 2). Ammonia concentrations 

ranged from 0.019 to 0.377 mg/L as nitrogen (N). Organic 

nitrogen concentrations were negligible in four samples, 

but in two samples (TM1008 and TM1009) the organic 

nitrogen concentrations were more than 50 percent of the 

reduced nitrogen. Nitrate was not detected in any of the 

samples above the detection limit of 0.06 mg/L. Confined 

aquifers are less susceptible to contamination than unconfined 

aquifers because confining units prevent chemicals that are 

applied on the land surface from easily infiltrating through 

the confining material and into the confined aquifers. Nitrite 

was not detected in five of the six samples and was negligible 

in only one. Orthophosphate was detected in five of the six 

samples, but concentrations were typically low; the maximum 

concentration was 0.031 mg/L (as phosphorus).

Trace Elements

The most commonly detected trace elements were 

aluminum, arsenic, barium, boron, iron, lithium, manganese, 

nickel, molybdenum, uranium, zinc, and strontium, all of 

which were detected in every sample (table 3). The trace 

elements detected in the greatest concentrations were 

barium, boron, iron, lithium, manganese, and strontium. 

Aluminum concentrations ranged from 0.9 to 95.5 μg/L; one 

sample (TM1532) exceeded the SMCL (50 μg/L). Arsenic 

concentrations ranged from 1.3 to 20.4 μg/L; two samples 

(TM1002 and TM1532) exceeded the MCL for arsenic of 

10 μg/L. Barium concentrations ranged from 120 to 408 μg/L, 

but the MCL for barium (2,000 μg/L) was not exceeded. 

Boron concentrations ranged from 9 to 174 μg/L; MCLs 

have not been established for boron. Iron concentrations 

ranged from 165 to 528 μg/L; two samples (TM1503 and 

TM2355) exceeded the SMCL for iron (300 μg/L). Lead 

was detected in two samples, but neither sample exceeded 

the MCL (15 μg/L). Lithium concentrations ranged from 4.7 

to 53.5 μg/L; MCLs have not been established for lithium. 

Manganese concentrations ranged from 58.0 to 93.2 μg/L; 

the Federal SMCL for manganese (50 μg/L) was exceeded in 

all six samples, but the New York State MCL (300 μg/L) was 

not exceeded in any sample. Strontium concentrations ranged 

from 122 to 567 μg/L, but no MCLs have been established 

for strontium. Uranium concentrations ranged from 0.05 to 

1.75 μg/L; no samples exceeded the Federal MCL of 30 μg/L. 
40 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York Table 2. Physical properties, concentrations of major inorganic ions, and concentratins of nutrients in groundwater samples from confined aquifers in the lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York, 2006-2007. [S&G, sand and gravel; 72008, USGS National Water Information System (NWIS) parameter code; mg/L, milligrams per liter; ug/L, micrograms per liter; <, less than; - -, not analyzed. Sampling site loca- tions are shown in figure 13.] USGS site name TM1008 TM1009 TM1002 TM1503 TM1532 TM2355 Date sampled 12/13/2006 12/13/2006 12/20/2006 12/20/2006 12/20/2006 8/16/2007 Well identification number 422236 076240401 422236 076240402 422407 076260101 422315 076244401 422318 076243801 422345 076251101 Aquifer type S&G, basal confined S&G, basal confined S&G, intermediate confined S&G, basal confined S&G, upper confined S&G, basal confined Physical properties Parameter code Units Values of physical properties Drinking water standard Well depth, below land surface 72008 ft 187 126 88 197 95 145 pH (field) 00400 pH 8.0 7.8 7.7 8.1 8.1 7.6 Specific conductance (field) 00095 uS/cm 318 492 266 291 335 339 Water Temperature 00010 °C 9.8 9.8 9.5 8.0 13.0 19.4 Major Inorganic Ions Concentration of chemical constituents Hardness, filtered, as CaCO3 00900 mg/L 139 222 124 126 113 152 Calcium, filtered 00915 mg/L 41 63.6 36.3 34.4 30.5 42.7 Magnesium, filtered 00925 mg/L 8.63 14.8 7.84 9.44 8.71 10.7 Potassium, filtered 00935 mg/L 0.66 0.88 0.74 0.67 0.74 0.83 Sodium, filtered 00930 mg/L 9.47 10.5 11.1 13.7 28.8 13.3 60a Alkalinity, filtered, as CaCO3, (lab) 29801 mg/L 146 142 143 145 145 163 250c

Bicarbonate, filtered, as CaCO3 29805 mg/L 178 173 174 177 177 199 Chlorides, filtered 00940 mg/L 8.77 35.6 0.67 1.56 13.8 2.1 Fluoride, filtered 00950 mg/L 0.17 0.09 0.31 0.39 0.71 0.29 2.2bSilica, filtered 00955 mg/L 10.2 7.46 12.8 11.9 11.3 13.2 Sulfate, filtered 00945 mg/L 11.4 47.1 8.08 12.5 13.5 15.9 250cDissolved solids, at 180 °C 01056 mg/L 170 266 167 173 198 196 

Nutrients

Ammonia, as N, filtered 00608 mg/L 0.067 0.019 0.224 0.256 0.377 0.151Nitrate, as N, NO2+NO3, filtered 00631 mg/L <0.060 <0.060 <0.060 <0.060 <0.060 <0.060 10bNitrite, as N, filtered 00613 mg/L <0.002 <0.002 <0.002 <0.002 0.001 <0.002 1bOrganic+ammonia, as N, filtered 00607 mg/L 0.2 0.1 0.3 0.3 0.5 0.2
Groundwater Quality 41

Table 2. Physical properties, concentrations of major inorganic ions, and concentratins of nutrients in groundwater samples from confined aquifers in the lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York, 2006-2007. [S&G, sand and gravel; 72008, USGS National Water Information System (NWIS) parameter code; mg/L, milligrams per liter; ug/L, micrograms per liter; <, less than; - -, not analyzed. Sampling site locations are shown in figure 13.]

USGS site name TM1008 TM1009 TM1002 TM1503 TM1532 TM2355

Date sampled 12/13/2006 12/13/2006 12/20/2006 12/20/2006 12/20/2006 8/16/2007

Well identification number 422236 076240401 422236 076240402 422407 076260101 422315 076244401 422318 076243801 422345 076251101

Aquifer type

S&G, 

basal 

confined

S&G, 

basal 

confined

S&G, 

intermediate 

confined

S&G, 

basal 

confined

S&G, 

upper 

confined

S&G, 

basal 

confined

Nutrients Parameter code Units Concentration of chemical constituents Drinking water standard

Organic+ammonia, as N, unfiltered 00605 mg/L 0.6 0.2 0.3 0.3 0.4 --Orthophosphate, as P, filtered 00671 mg/L <0.006 0.003 0.031 0.011 0.011 0.031Phosphorus, filtered 00666 mg/L <0.006 <.006 0.031 0.008 0.008 --Phosphorus, unfiltered 00665 mg/L -- -- 0.034 0.03 0.012 --

a USEPA Drinking Water Advisory Taste Threshold.b NYSDOH Maximum Contaminant Level.c USEPA Secondary Drinking Water standard.
42 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

Table 3. Concentrations of trace metals in groundwater samples from confined aquifers in the lower Sixmile Creek and Willseyville Creek trough, Tompkins County, New York, 2006–2007. [E, estimated; S&G, sand and gravel; 01106, USGS National Water Information System (NWIS) parameter code; mg/L, milligrams per liter; ug/L, micrograms per liter; <, less than; - -, not analyzed]. Sampling sites locations are shown in figure 13.]

USGS site name TM1008 TM1009 TM1002 TM1503 TM1532 TM2355

Date sampled 12/13/2006 12/13/2006 12/20/2006 12/20/2006 12/20/2006 8/16/2007

Well identification number 422236 076240401 422236 076240402 422407 076260101 422315 076244401 422318 076243801 422345 076251101

Aquifer type

S&G

basal 

confined 

S&G

basal 

confined 

S&G

intermediate 

confined 

S&G

basal 

confined 

S&G

upper 

confined 

S&G

basal 

confined 

Trace metals

Parameter 

code 

(filtered)

Units Concentrations of chemical constituents

Parameter 

code 

(unfiltered)

Drinking water 

standard

Well depth, below land surface ft 187 126 88 197 95 145 Aluminum, filtered 01106 ug/L E1.1 E1.3 E0.9 2.5 95.5 33 01105 50cAntimony, filtered 01095 ug/L 0.19 2.02 <0.06 <0.06 <0.06 <0.2 01097 6a,bArsenic, filtered 01000 ug/L 2.0 1.3 13.1 4.5 20.4 3.8 01002 10aBarium, filtered 01005 ug/L 408 194 228 180 120 203 01007 2,000a,bBeryllium, filtered 01010 ug/L <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 01012 4a,bBoron, filtered 01020 ug/L 19 9 31 48 174 34 01020Cadmium, filtered 01025 ug/L <0.04 E0.02 <0.04 <0.04 E0.03 E0.01 01027 5a,bChromium, filtered 01030 ug/L <0.12 <0.12 <0.12 <0.12 <0.12 <0.60 01034 100a,bCobalt, filtered 01035 ug/L 0.07 0.60 <0.04 <0.04 0.06 E0.02 01037Copper, filtered 01040 ug/L <0.40 <0.40 <0.40 <0.40 0.57 <1.2 01042 1,000cIron, filtered 01046 ug/L 296 192 255 528 165 316 01045 300b,cLead, filtered 01049 ug/L <0.12 <0.12 <0.12 <0.12 0.35 1.14 01051 15dLithium, filtered 01130 ug/L 7.3 10.0 4.7 6.4 53.5 7.9 01132Manganese, filtered 01056 ug/L 93.2 77.5 61.7 58.0 93.2 63.4 01055 50c–300bMolybdenum, filtered 01060 ug/L 2.4 1.3 4.3 5.5 19.5 3.5 01062Nickel, filtered 01065 ug/L 0.14 1.6 0.08 0.20 0.16 E0.11 01067Selenium, filtered 01145 ug/L <0.08 0.38 <0.08 <0.08 <0.08 <0.08 01147 50a,bSilver, filtered 01075 ug/L <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 01077 100a,bStrontium, filtered 01080 ug/L 234 122 393 567 552 388 01082Thallium, filtered 01057 ug/L <0.04 <0.04 <0.04 E0.02 <0.04 <0.18 01059Vanadium, filtered 01085 ug/L E0.03 0.10 <0.04 <0.04 <0.08 -- --Uranium, natural, filtered 22703 ug/L 0.25 1.75 0.13 0.05 0.38 0.43 28011 30aZinc, filtered 01090 ug/L 1.1 0.67 0.68 1.3 1.9 E1.5 01092 5,000b,c

a USEPA Maximum Contaminant Level.b NYSDOH Maximum Contaminant Level.c USEPA Secondary Maximum Contaminant Level.d USEPA Treatment Technique.e USEPA Proposed Maximum Contaminant Level.
Summary 43

Comparison to Other Stratified-Drift Aquifers in 

Tompkins County

Calcium dominates the cation composition and 

bicarbonate dominates the anion composition in samples 

from this study area and most samples from the three other 

areas (fig. 22). The exceptions are two samples collected in 

Upper Buttermilk Creek and Danby Creek valleys and two 

samples collected in Upper Sixmile Creek and West Branch 

Owego Creek valleys, which were sodium bicarbonate-tosodium chloride type waters (fig. 22). The chemistry of water 

from two wells in upper Sixmile Creek valley that were of a 

sodium bicarbonate-to-sodium chloride type water (fig. 22) 

was due to enrichment from brackish water in bedrock that 

locally discharges to the valley fill (Miller, 2009). One sample 

(TM1009) in this study area was a mix of calcium-bicarbonate 

and calcium-sulfate water (fig. 22). Similar water chemistry in 

stratified-drift aquifers in all four study areas is not surprising 

because the geologic settings of the areas are similar—Valley 

Heads drift and Devonian shales and siltstones. 

Summary

In 2002, the U.S. Geological Survey, in cooperation with 

the Tompkins County Planning Department, began a series of 

studies of the stratified-drift aquifers in Tompkins County to 

provide geohydrologic data for planners to develop a strategy 

to manage and protect their water resources. This aquifer 

study, in lower Sixmile Creek and Willseyville Creek trough, 

is the second in that series of aquifer studies. This study area 

is within the northern area of the Appalachian Plateau and 

extends 9.7 mi from the boundary between Tompkins County 

and Tioga County in the south, northward to just south of the 

City of Ithaca. In lower Sixmile Creek and Willseyville Creek 

trough, the major aquifers are confined, but there also is at 

least one unconfined aquifer in the Brooktondale Delta area 

that is relatively unused. 

Scouring of bedrock in the preglacial lower Sixmile 

Creek and Willseyville Creek valleys by glaciers and 

subglacial meltwaters has truncated hillside spurs, formed 

U-shaped transverse valley profiles, smoothed valley walls, 

and deepened the valleys by as much as 300 ft, forming 

a continuous trough, which was subsequently filled with 

unconsolidated deposits. The unconsolidated deposits in the 

study area consist mostly of glacial drift, both unstratified 

drift (till) and stratified drift (laminated lake, deltaic, and 

glaciofluvial sediments), as well as some post-glacial stratified 

sediments (lake-bottom sediments deposited in reservoirs, 

peat and muck deposited in wetlands, and alluvium deposited 

by streams). The multiple advance and retreat of the ice in the 

study area resulted in multiple sequences of various glacial 

deposits. A large moraine (Valley Heads Moraine) dominates 

the southern part of the study area; a large delta dominates the 

central part, and ground moraine (mostly till) dominates the 

northern part. Glacial sediments in the center of the trough 

typically range from 150 to 200 ft but can be greater than 

300 ft in some places. 

The surficial, coarse-grained sediments (sand and gravel) 

that comprise the delta near Brooktondale form a small 

unconfined aquifer (0.3 mi2 in area) in the central part of the 

study area, which is relatively unused as a water supply. Much 

of the upper part of the delta has been removed by several 

aggregate mining operations, but there remain sufficient 

amounts of sand and gravel in most places to form a thin 

aquifer. The major sources of recharge to the unconfined 

aquifer are direct infiltration of precipitation where water 

moves predominantly in a downward direction through the 

unsaturated zone toward the water table and unchanneled 

surface and subsurface runoff from adjacent upland areas that 

seep into the aquifer along the trough walls.

 In most parts of the study area, two confined aquifers are 

present—an upper confined and a basal confined. However, 

underlying the central part of the Brooktondale Delta, there 

are as many as four confined aquifers. The major sources of 

recharge to the confined aquifers are (1) direct infiltration 

of precipitation where the aquifers crop out at land surface, 

mostly along the west trough wall in the south and central 

parts of the study area, and to a lesser degree, along the east 

trough wall; (2) unchanneled surface and subsurface runoff 

from adjacent upland areas that seeps into the aquifer along 

the west trough walls; (3) subsurface flow from underlying till 

or bedrock at the lateral contacts between the aquifers and the 

trough walls; and (4) from bedrock adjacent to the aquifers in 

the bottom and sides of the trough.

Groundwater in the southern part of the deltaic 

aquifer flows to the west and discharges into Beaver Creek. 

Groundwater in the northern part of the deltaic aquifer flows 

to the northwest where some of the groundwater discharges 

to springs along the northern margin of the delta to Sixmile 

Creek, and some discharges to springs along the western 

margin of the delta and then to Beaver Creek. Groundwater 

also discharges to ponds that have been created where gravel 

mining extends below the water table. 

Just north of a major surface-water divide in the southern 

part of the study area, groundwater in the confined aquifers on 

the west side of the trough initially flows eastward from the 

west valley wall to the center of the valley, changing course 

and flowing northward. The upper confined aquifer at the 

northern edge of the central area of the trough either pinches 

out at depth or has been penetrated by Sixmile Creek and is 

exposed beneath the floodplain where groundwater discharges 

into Sixmile Creek. Groundwater in the basal confined aquifer 

ultimately discharges into Sixmile Creek and to the Ithaca 

Reservoir in the northern part of the study area.

In lower Sixmile Creek and Willseyville Creek trough 

about 600 people rely on groundwater from the stratifieddrift aquifer system. In addition, water is used by nonpermanent residents such as staff at commercial facilities. The 

estimated total groundwater use for the estimated 600 persons 

withdrawing water from the stratified-drift aquifers for human 
44 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

Figure 22. Piper diagram illustrating variability in major ion composition of groundwater in lower Sixmile Creek and 

Willseyville Creek trough, upper Sixmile Creek and West Branch Owego Creek valleys, Virgil Creek valley, and upper 

Buttermilk and Danby Creek valleys, Tompkins County, New York.

PERCENT

Calcium

1 00

8 0

6 0

4 0

2 0

0

 0

 20

 40

 60

 80

 100

0

2 0

4 0

6 0

8 0

1 00

Chloride 

0

2 0

4 0

60

8 0

1 00

10 0

8 0

6 0

4 0

2 0

0 100

 80

 60

 40

 20

 0

0

2 0

4 0

6 0

8 0

1 0 0

0

2 0

4 0

6 0

80

1 0 0

1 0 0

8 0

60

4 0

2 0

0

1 0 0

80

60

40

20

0

EXPLANATION

Virgil Creek valley groundwater sample

Lower Sixmile Creek and Willseyville Creek trough groundwater sample

Upper Sixmile Creek and West Branch Owego Creek valleys groundwater sample

PERCENT

PERCENT

Sulfate plus Chloride

Calcium plus Magnesium

Sulfate

Magnesium

Sodium plus Potassium

Bicarbonate

Upper Buttermilk Creek and Danby Creek valleys groundwater sample

TM1009

TM1009
Selected References 45

consumption is about 45,000 gal/d or 0.07 ft3/s based on an 

average water use of 75 gal/d per person (for self-supplied 

water systems in New York) .

Water samples were collected from six wells (two test 

wells and four private residential wells) from December 

2006 through August 2007 and analyzed to characterize 

the chemical quality of groundwater in the confined 

aquifers. Results indicate that groundwater used for human 

consumption is generally of acceptable quality, although 

concentrations of some constituents exceeded at least one 

drinking-water standard at three of the six wells. 

Water in the sand-and-gravel aquifers is predominantly 

a calcium-bicarbonate type. The cation that was detected in 

the largest concentration was calcium, ranging from 30.5 to 

63.6 mg/L. Sodium values ranged from 9.47 to 28.8 mg/L; 

no samples exceeded the USEPA Drinking Water Advisory 

for sodium. The anion that was detected in the greatest 

concentration was bicarbonate, while chloride and sulfate 

were detected in generally lesser concentrations. Bicarbonate 

values (as CaCO3) ranged from 173 to 199 mg/L. Chloride 

values ranged from 0.67 to 35.6 mg/L and did not exceed the 

Secondary Maximum Contaminant Level of 250 mg/L. Sulfate 

values ranged from 8.08 to 47.1 mg/L and did not exceed the 

Secondary Maximum Contaminant Level of 250 mg/L. Nitrate 

was not detected in any of the samples above the detection 

limit of 0.06 mg/L. Nitrite was not detected in five of the six 

samples and was negligible in the other sample.

The most commonly detected trace elements were 

aluminum, arsenic, barium, boron, iron, lithium, manganese, 

nickel, and strontium, all of which were detected in every 

sample. The elements detected in the largest concentrations 

were barium, boron, iron, lithium, manganese, strontium, 

and uranium. Aluminum concentrations ranged from 0.9 to 

95.5 μg/L; one sample exceeded the Secondary Maximum 

Contaminant Level of 50 μg/L. Arsenic concentrations ranged 

from 1.3 to 20.4 μg/L; two samples exceeded the USEPA 

Maximum Contaminant Level of 10 μg/L for arsenic. 

Selected References

Ashworth, A.C., Miller, N.G., Schmidt, V.E., and Willenbring, 

Jane, 1997: The Sixmile Creek site, Ithaca, New York, 

and potential problems with mid-Wisconsin regional 

paleoclimatic interpretations: GSA annual meeting with 

abstracts, Salt Lake City, v. 29(6), p. 37. 

Cadwell, D.H., 1972, Late Wisconsinan deglaciation 

chronology of the Chenango River valley and vicinity, New 

York: Binghamton, State University of New York, Ph.D. 

dissertation, 102 p.

Cadwell, D.H., Fleisher, P.J., and Muller, E.H., 1988, 

Stagnant ice conditions during retreat in western New York: 

Geological Society of American Abstracts, v. 20, p. 11.

Clayton, K.M., 1965, Glacial erosion in the Finger 

Lakes region (New York State, USA): Zeitschrift fur 

Geomorphologie, NF9, p. 50–62.

Crain, L.J., 1966, Ground-water resources of the Jamestown 

area, New York, with emphasis on the hydrology of the 

major stream valleys: New York State Water Resources 

Commission Bulletin 58. 167 p.

Crain, L.J., 1974, Ground-water resources of the western 

Oswego River basin, New York: New York State 

Department of Environmental Conservation Basin Planning 

Report ORB–5, 137 p.

Cressey, G.B., 1966, Land forms. in J.H. Thompson, editor. 

Geography of New York State, Syracuse University Press, 

Syracuse, New York, 543 p.

Freeze, R.A. and Cherry, J.A., 1979, Groundwater, PrenticeHall, Inc. Englewood Cliffs, NJ., 604 p.

Fullerton, D.S., 1980, Preliminary correlation of post-Erie 

interstadial events (16 000–10 000 radiocarbon years 

before present) central and eastern Great Lakes region, and 

Hudson, Champlain, and St. Lawrence lowlands, United 

States and Canada: U.S. Geological Survey Professional 

Paper 1089, 52 p.

Haeni, F.P., 1988, Application of seismic-refraction techniques 

to hydrologic studies: U.S. Geological Survey Techniques 

of Water-Resources Investigations, book 2, chap. D2, 86 p. 

Hem, J.D., 1985, Study and interpretation of the chemical 

characteristics of natural water (3rd ed.): U.S. Geological 

Survey Water Supply Paper 2254, 264 p.

Isachsen, Y.W., Landing E., Lauber, J.M., Rickard, L.V., and 

Rogers, W.B., Editors, 1991, Geology of New York— A 

Simplified Account: New York State Museum Educational 

Leaflet no. 28, 284 p.

Kappel, W.M., Miller, T.S., 2003, Hydrogeology of the 

Tully Trough— Southern Onondaga County and Northern 

Cortland County, New York: U.S. Geological Survey 

Water-Resources Investigations Report 03–4112, 16 p.

Kappel, W.M., Miller, T.S., and Hetcher, K.K., 2001, 

Hydrogeology of the Tully Lakes area in southern 

Onondaga and northern Cortland Counties, New York: 

U.S. Geological Survey Water-Resources Investigations 

Report 01–4166, 16 p.

Kontis, A.L., Randall, A.D., and Mazzaferro, D.L. 2004, 

Regional hydrology and simulation of flow of stratified-drift 

aquifers in the glaciated northeastern United States: U.S. 

Geological Survey Professional Paper 1415–C, 156 p.
46 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York

Lane, J.W., Jr., White, E.A., Steele, G.V., and Cannia, J.C., 

2008, Estimation of bedrock depth using the horizontalto-vertical (H/V) ambient-noise seismic method, in

Symposium on the Application of Geophysics to 

Engineering and Environmental Problems, April 6–10, 

2008, Philadelphia, Pennsylvania, Proceedings: Denver, 

Colorado, Environmental and Engineering Geophysical 

Society, 13 p.

Miller, T.S., 2009, Geohydrology and Water Quality of the 

Valley-Fill Aquifer System in the Upper Sixmile Creek and 

West Branch Owego Creek Valleys in the Town of Caroline, 

Tompkins County, New York: U.S. Geological Science 

Investigations Report 2009–5173, 56 p.

Miller, T.S., 2000, Unconsolidated Aquifers in Tompkins 

County, New York: U.S. geological Survey WaterResources Investigation Report 00–4211, 1 plate.

Miller, T.S., Bugliosi, E.F., and Reddy, J.E., 2008, 

Geohydrology of the unconsolidated valley-fill aquifer in 

the Meads Creek valley, Schuyler and Steuben Counties, 

New York: U.S. Geological Survey Scientific Investigations 

Report 2008–5122, 32 p 

Miller, T.S., and Randall, A.D., 1991, Hydrogeology of 

glacial drift in through valleys near Dryden and Cortland, 

New York, in Ebert, J.R, ed., Guidebook for field trips, 

63rd Annual Meeting, New York Geological Association: 

Oneonta, State University of New York, p. 463–488.

Miller, T.S., Sherwood, D.A., Jeffers, P.M., Mueller, Nancy, 

1998, Hydrology, water-quality, and simulation of groundwater flow in a glacial aquifer system, Cortland County, 

New York: Water-Resources Investigations Report WRI 

96–4255, 84 p.

Muller, E.H. and Cadwell, D.H., 1986, Surficial geologic map 

of New York, Finger Lakes sheet: New York State Museum 

and Chart Series 40, scale 1:250,000.

Mullins, H.T., and Hinchey, E.J., 1989. Erosion and infill of 

New York Finger Lakes—Implications for Laurentide ice 

sheet deglaciation: Geology, v. 17, p. 622–625.

Mullins, H.T., Wellner, RW., Petruccione, J.L., Hinchey, K.J., 

and Wanzer, S., 1991, Subsurface geology of the Finger 

Lakes region, in Ebert, J.R, ed., Field trip guidebook, 

New York Geological Association, 63rd Annual Meeting: 

Oneonta, State University of New York, Department of 

Earth Sciences, p. 1–54.

Neeley, J.A., 1961, Soil Survey of Tomkins County, New 

York: U.S. Department of Agriculture in cooperation with 

Cornell University Agricultural Experiment Station, series 

1961, no. 25, 241 p.

Randall, A.D, 1979, Ground water in Dale Valley, New York: 

U.S. Geological Survey Water Resources Investigations 

Report 78–120, 85 p. 

Randall, A.D., 2001, Hydrogeologic framework of stratifieddrift aquifers in the glaciated northeastern United States: 

U.S. Geological Survey Professional Paper 1415–B, 179 p.

Randall, A.D., Snavely, D.S., Holecek, T.P., Waller, R.M., 

1988, Alternative sources of large seasonal ground-water 

supplies in the headwaters of the Susquehanna River 

basin, New York: Water-Resources Investigations Report 

85–4127, 121 p.

Rich, J.L. and Filmer, E.A., 1915, The Interglacial Gorges of 

Six Mile Creek at Ithaca, New York: Journal of Geology, 

v. 23. p. 59–80.

Scott, J.H., Tibbetts, B.L., and Burdick, R.G., 1972, Computer 

analysis of seismic refraction data: U.S. Bureau of Mines 

Report of Investigation 7595, 95 p.

Sloto, R.A., and Crouse, M.Y., 1996, HYSEP: A computer 

program for streamflow hydrograph separation and analysis: 

U.S. Geological Survey Water-Resources Investigations 

Report 96–4040, 46 p.

U.S. Environmental Protection Agency, 2006, Drinking water 

standards and health advisories: Washington, D.C., Office 

of Water, EPA 822–R–06–013, Oct. 1996, 12 p. 

U.S. Geological Survey, 2004, Field methods, accessed 

October, 2004, at http://water.usgs.gov/owq.

U.S. Geological Survey, variously dated, National field manual 

for the collection of water-quality data: U.S. Geological 

Survey Techniques of Water-Resources Investigations, book 

9, chaps. A1–A9, at http://pubs.water.usgs.gov/twri9A.

Williams, H.S., Tarr, R.S., and Kindle, E.M., 1909, 

Description of the Watkins Glen-Catatonk District, New 

York: U.S. Geological Survey Geologic Atlas, Folio 169.
Selected References 47

Appendix 1. Records of selected wells in lower Sixmile Creek and Willseyville Creek trough, Tompkins and Tioga Counties, New York. [S&G, sand and gravel; --, no data; ft, feet; dia. (in), diameter in inches; gal/min, gallons per minute; gal/ft, gallons per foot; psi, pounds per square inch; do., ditto; >, greater than]

Well 

number

Date 

drilled

Well 

depth 

(ft)

Depth 

of 

casing 

(ft)

Casing 

diameter 

(in)

Altitude 

land 

surface 

(ft)

Aquifer type

Water 

level 

below 

land 

surface 

(ft)

Altitude 

water 

level 

(ft)

Date 

water 

level 

measured

Depth 

to 

bedrock 

(ft)

Altitude 

top of 

bedrock 

(ft)

Reported 

yield 

(gal/min)

Remarks

TM 21 1962 45 45 6 981 S&G -- -- -- -- -- -- Owner reports well 

depth 40–50 ft.

TM 32 10/7/1980 77 -- -- 988 S&G 15 968 10/7/1980 -- -- -- USGS test boring. 0–6 

silt, 6–16 silt with pebbles (till?), 16–33 gravel, 33–53 silty gravel, 53–71 silty sand, 71–77 clay (laminated), 77–77.5 ft till?

TM 42 10/9/1980 73 -- -- 986 S&G 9 986 10/9/1980 -- -- -- USGS test boring. 0–16 

pebbly sandy silt (alluvium), 16–28 silt, 28–33 dirty gravel, 32–51 interlayered dirty gravel, sand, slit, and clay, 51–71 ft grey pebbly and clayey silt (till).

TM 50 1965 105 105 6 971 S&G 

(confined)

2 969 1965 -- -- -- Sulfur odor.

TM 51 1950 94 94 6 971 S&G 

(confined)

3 968 11/1/1965 -- -- -- Sulfur odor.

TM 58 1961 25 -- -- 900 Till -- -- -- -- -- -- Test boring. 0–6 S&G, 

6–25 ft till.

TM 60 8/22/1966 101 29 5 935 Shale Flows -- 8/22/1966 29 906 30 0–29 S&G, 29–101 ft 

shale.

TM 65 1958 146 146 6 868 S&G 

(confined)

Flows -- -- -- -- -- Flows. Sulfur and iron.

TM 82 1965 104 44 6 990 Shale 24 966 11/1/1965 42 948 10 0–42 till, 42–104 ft 

shale.

TM 86 1965 206 28 6 1,130 Shale 40 1,090 11/1/1965 28 1,102 3 Bedrock at 28 ft.TM 92 6/15/1957 172 172 5 920 S&G 

(confined)

-- -- -- -- -- -- --

TM 93 1964 150 15 6 970 Shale -- -- -- 15 955 -- --TM 95 1951 167 60 6 900 Shale -- -- -- 60 840 -- --
48 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York Appendix 1 48 Appendix 1. Records of selected wells in lower Sixmile Creek and Willseyville Creek trough, Tompkins and Tioga Counties, New York. [S&G, sand and gravel; --, no data; ft, feet; dia. (in), diameter in inches; gal/min, gallons per minute; gal/ft, gallons per foot; psi, pounds per square inch; do., ditto; >, greater than] Well number Date drilled Well depth (ft) Depth of casing (ft) Casing diameter (in) Altitude land surface (ft) Aquifer type Water level below land surface (ft) Altitude water level (ft) Date water level measured Depth to bedrock (ft) Altitude top of bedrock (ft) Reported yield (gal/min) Remarks TM 102 1964 96 22 6 935 Shale -- -- -- 18 917 2 -- TM 103 1965 235 67 6 900 Shale -- -- -- 67 833 2 -- TM 544 -- 163 163 6 917 S&G (confined) -- -- -- -- -- -- -- TM 550 -- 74 74 6 863 S&G (confined) -- -- -- -- -- -- -- TM 551 -- 70 70 6 865 S&G (confined) -- -- -- -- -- -- -- TM 552 -- 180 180 6 902 S&G (confined) -- -- -- -- -- -- -- TM 555 -- 100 28 6 1,046 Shale -- -- -- 28 1,018 -- -- TM 560 -- 190 40 6 1,114 Shale -- -- -- 40 974 -- -- TM 567 4/15/1991 83 30 6 1,055 Shale -- -- -- 30 1,025 -- -- TM 588 -- 97 97 6 1,061 S&G (confined) Flows >1,061 -- -- -- -- TM 983 6/18/1993 55 55 6 1,019.1 S&G (confined) 13 1,006.09 6/16/2003 -- -- 25 No log. 0–55 ft. Well ended in S&G. TM 984 6/26/1993 50 50 6 1,020.5 S&G (confined) 12.14 1,008.36 6/16/2003 -- -- 30 No log. 0–55 ft. Well ended in S&G. TM 987 -- 40 40 0 1,055 S&G (confined) -- -- -- -- -- -- -- TM1001 -- 104 94 6 830.4 Shale 6 824.4 6/6/2005 94 736 -- Well drilled 10 ft into bedrock. TM1002 -- 88 88 6 777 S&G (confined) +40 817 11/1/2006 -- -- 4 -- TM1003 9/15/1993 130 130 6 935 S&G (confined) 5 930 9/15/1993 -- -- -- 0–10 clay, 10–20 S&G, 20–30 till, 30–80 silty sand, 80–100 S&G, 100–120 clay, 120–130 S&G. TM1004 7/27/2006 42 -- -- 815 Till 4 811 7/27/2006 -- -- -- Bridge test boring. 0–5 till, 5–35 clay, 35–42 ft till.
49 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York Selected References 49 Appendix 1. Records of selected wells in lower Sixmile Creek and Willseyville Creek trough, Tompkins and Tioga Counties, New York. [S&G, sand and gravel; --, no data; ft, feet; dia. (in), diameter in inches; gal/min, gallons per minute; gal/ft, gallons per foot; psi, pounds per square inch; do., ditto; >, greater than] Well number Date drilled Well depth (ft) Depth of casing (ft) Casing diameter (in) Altitude land surface (ft) Aquifer type Water level below land surface (ft) Altitude water level (ft) Date water level measured Depth to bedrock (ft) Altitude top of bedrock (ft) Reported yield (gal/min) Remarks TM1008 12/12/2006 187 187 6 946 S&G (confined) Flows 947.56 12/16/2006 196 750 20 0–24 S&G, 24–36 clay, 36–50 S&G, 50–65 sand, 65–100 till, 100–122 clay, 122–133 S&G, 133–138 till, 138–157 S&G, 157–174 fine sand, 174–196 S&G, 196–200 ft shale. TM1009 12/14/2006 130 130 6 946 S&G (confined) Flows 951.69 12/2/2008 -- -- 25 0–24 S&G, 24–36 clay, 36–50 S&G, 50–65 sand, 65–100 till, 100–122 clay, 122–130 S&G, perforated casing 122–126 ft. TM1019 6/15/1979 304 304 6 985 S&G (confined) -- -- -- -- -- 20 0–10 till 10–30 fine sand, 30–74 clay, 74–78 S&G, 78–153 clay, 153–172 fine sand, 172–222 clay, 222–283 fine sand, 283–300 till, 300–302 clay, 302–304 ft gravel. TM1029 4/8/2005 69 69 5 1,015 S&G (confined) 48.15 966.62 4/8/2005 -- -- -- 0–19 S&G, 19–27 silt and clay, 27–37 ft S&G. TM1035 11/3/1938 74 -- -- 711.3 -- -- -- -- 64 647.3 -- Local number DH–1. 0–8 S&G, 8–31 silty S&G, 31–37 sandy clay, 37–64 ft sand with clay, 64–74 bedrock.
50 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York Appendix 1 50 Appendix 1. Records of selected wells in lower Sixmile Creek and Willseyville Creek trough, Tompkins and Tioga Counties, New York. [S&G, sand and gravel; --, no data; ft, feet; dia. (in), diameter in inches; gal/min, gallons per minute; gal/ft, gallons per foot; psi, pounds per square inch; do., ditto; >, greater than] Well number Date drilled Well depth (ft) Depth of casing (ft) Casing diameter (in) Altitude land surface (ft) Aquifer type Water level below land surface (ft) Altitude water level (ft) Date water level measured Depth to bedrock (ft) Altitude top of bedrock (ft) Reported yield (gal/min) Remarks TM1036 11/1/1938 40 -- -- 750 -- -- -- -- 40 710 -- Local number DH–2. 0–11 brown clay, 11–14 silt and ft sand, 14–40 silt and S&G (loose), 40 ft shale. TM1037 11/5/1938 94 -- -- 709.4 -- -- -- -- 94 615.4 -- Local number DH–3. 0–10 S&G, 10–30 till, 30–78 sand with silt & gravel, 78–82 sand, 82–94 till, 94 bedrock. TM1038 1/3/1938 125 -- -- 742.7 -- -- -- -- -- -- -- Local number DH–4. 0–20 S&G, 20–85 till? TM1039 11/2/1938 42 -- -- 711.4 -- -- -- -- 42 669.1 -- Local number DH–5. 0–6.5 S&G, silt, sand, gravel and boulders, 16–32 silty f. sand, 32–42 till, 42 ft bedrock. TM1040 11/6/1938 8 -- -- 715.3 -- -- -- -- 8 707.3 -- Local number DH–6. 0–8 silty S&G, 8 ft bedrock. TM1041 11/9/1938 -- -- -- -- -- -- -- Local number DH–9. TM1042 1/3/1938 125 0 0 742.7 -- -- 0 -- 0 - 0 0–20 S&G, 20–85 ft till?, TM1043 11/2/1938 42 0 0 711.4 -- -- 0 -- 42.3 669.1 0 0–6.5 alluvial sand and gravel, silt, sand, gravel and boulders, 16–32 beds of silty fine sand, 32–42 till, 42 ft bedrock. TM1044 11/6/1938 8 0 0 715.3 -- -- 0 -- 8 707.3 0 0–8 silty sand and gravel, 8 ft bedrock TM1045 11/7/1938 30 0 0 730 -- -- 0 -- 22 708 0
51 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York Selected References 51 Appendix 1. Records of selected wells in lower Sixmile Creek and Willseyville Creek trough, Tompkins and Tioga Counties, New York. [S&G, sand and gravel; --, no data; ft, feet; dia. (in), diameter in inches; gal/min, gallons per minute; gal/ft, gallons per foot; psi, pounds per square inch; do., ditto; >, greater than] Well number Date drilled Well depth (ft) Depth of casing (ft) Casing diameter (in) Altitude land surface (ft) Aquifer type Water level below land surface (ft) Altitude water level (ft) Date water level measured Depth to bedrock (ft) Altitude top of bedrock (ft) Reported yield (gal/min) Remarks TM1251 8/18/2000 179 46 6 1,097 Shale 40 1,057 8/18/2000 44 1,053 3 0–40 dry gravel, 40–44 wet gravel, 44–179 ft shale. TM1260 10/7/2000 26 26 5 1,045 S&G (unconfined) 10 1,035 10/7/2000 0 -- 4.5 0–26 ft sand and gravel. TM1281 11/16/2000 338 26 6 1,075 Shale 3 1,072 11/16/2000 25 1,050 0.25 Yield 0.25 gal/min. 0–25 till, 25–338 ft shale. TM1296 11/22/2000 75 51 5 1,042 Shale 22 1,020 11/22/2000 51 991 10 0–51 hardpan (till?), 51–75 ft shale. TM1295 1/29/2001 120 20 6 1,128 Shale 45 1,083 1/29/2001 10 1,118 5 0–10 till, 10–120 ft shale. DD = 30 ft @ 5 gal/min. TM1309 4/14/2001 94 94 5 858 Sand (confined) Flows >862.50 4/14/2001 -- -- 1 Flows 0.25 gal/min. 0–42 clay w/ S&G, 42–94 clay and flow- ing sand, 94 ft sand. TM1319 7/13/2001 200 55 6 1,038 Shale 43 995 7/13/2001 53 985 2 0–53 gravel, 53–200 ft shale. TM1320 5/25/2001 150 35 5 1,210 Shale 15 1,195 5/25/2001 27 1,183 4.5 0–17 till, 17–19 S&G, 19–27 till, 27–150 ft grey shale. TM1355 6/3/2002 188 67 6 1,065 Shale 70 995 6/3/2002 64 1,001 5 0–10 till, 10–13 S&G, 13–30 till, 30–32 gravel, 32–64 till, 64–188 ft shale. TM1380 9/6/2001 199 30 6 1,115 Shale -- -- -- 26 1,089 3 0–26 till, 26–199 ft shale. TM1408 5/7/2003 90 90 6 1,128 S&G? -- -- -- 91 1,037 8 Bedrock at 91 ft. TM1423 12/12/2001 173 28 6 874.4 Shale 14.48 859.48 11/17/2006 27 847.4 3 0–27 clay, 27–173 ft shale. TM1503 5/31/2002 197 197 5 855 Sandy gravel (confined) Flows -- -- -- -- 8 0–7 till, 7–20 clay, 20–58 till, 58–62 gravel, 62–74 till, 74–112 clay and sand,112–127 sand, 127–196 clay and sand, 196–197 ft 

S&G.
52 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York Appendix 1 52 Appendix 1. Records of selected wells in lower Sixmile Creek and Willseyville Creek trough, Tompkins and Tioga Counties, New York. [S&G, sand and gravel; --, no data; ft, feet; dia. (in), diameter in inches; gal/min, gallons per minute; gal/ft, gallons per foot; psi, pounds per square inch; do., ditto; >, greater than] Well number Date drilled Well depth (ft) Depth of casing (ft) Casing diameter (in) Altitude land surface (ft) Aquifer type Water level below land surface (ft) Altitude water level (ft) Date water level measured Depth to bedrock (ft) Altitude top of bedrock (ft) Reported yield (gal/min) Remarks TM1506 6/4/2002 343 31 6 1,180 Shale -- -- -- 31 1,149 0.5 0–31 till, 31–343 ft shale. TM1532 7/2/2002 95 95 6 852 S&G (confined) Flows -- -- -- -- 50 Artesian flow. 0–11 till, 11–16 gravel, 16–95 hardpan and clay (till?), 95–100 ft gravel. TM1533 6/28/2002 58 58 6 1,035 S&G (confined) 40 995 6/28/2002 -- -- 10 0–57 hardpan (till?), 57–58 ft large gravel. TM1590 9/6/2002 120 52 6 1,091 Shale 32 1,059 9/6/2002 49 1,042 10 0–49 till, 49–120 ft shale. TM1611 10/9/2002 280 21 6 1,082 Shale 25 1,057 10/9/2002 8 1,074 2 0–8 till, 8–280 ft shale. TM1645 1/8/2003 31 31 5 1,070 S&G (confined) 4 1,066 1/8/2003 -- -- 20 0–26 clay and some gravel, 26–31 ft gravel. TM1671 4/29/2003 135 126 6 1,112 Shale 60 1,052 4/29/2003 126 986 5 0–100 till, 100–126 black sand, 126–135 ft shale. TM1677 4/28/2003 240 29 6 1,077 Shale -- -- -- 22 1,055 1.5 0–22 till, 22–240 ft shale. TM1683 5/20/2003 180 59 6 1,155 Shale 80 1,075 5/20/2003 58 1,097 2 0–30 till, 30–40 dirty gravel, 40–58 till, 58–180 ft shale. TM1698 6/3/2003 78 78 6 974 S&G (confined) Flows -- 6/3/2003 -- -- 25 Artesian flow. 0–3 Hardpan, 3–18 clay, 18–76 sand, 76–78 ft gravel. TM1732 7/23/2003 101 101 6 1,085 S&G (unconfined) 80 1,005 7/23/2003 -- -- 10 0–30 till, 30–60 dry gravel, 60–80 coarse sand, 80–100 ft gravel. TM1760 3/23/2004 78 78 6 872 S&G (confined) 5 867 3/23/2004 -- -- 15 0–10 till, 10–40 sandy clay, 40–50 S&G, 50–70 silty sand, 70–78 ft S&G. TM1896 8/5/2004 66 66 6 1,070 S&G (confined) -- -- -- -- -- 10 --
Selected References 53

Appendix 1. Records of selected wells in lower Sixmile Creek and Willseyville Creek trough, Tompkins and Tioga Counties, New York. [S&G, sand and gravel; --, no data; ft, feet; dia. (in), diameter in inches; gal/min, gallons per minute; gal/ft, gallons per foot; psi, pounds per square inch; do., ditto; >, greater than]

Well 

number

Date 

drilled

Well 

depth 

(ft)

Depth 

of 

casing 

(ft)

Casing 

diameter 

(in)

Altitude 

land 

surface 

(ft)

Aquifer type

Water 

level 

below 

land 

surface 

(ft)

Altitude 

water 

level 

(ft)

Date 

water 

level 

measured

Depth 

to 

bedrock 

(ft)

Altitude 

top of 

bedrock 

(ft)

Reported 

yield 

(gal/min)

Remarks

TM1898 8/13/2004 135 135 6 838 S&G 

(confined)

 2 836 8/14/2004 -- -- 8 0–25 clay, 25–100 clay 

and silt, 100–105 silty gravel, 105–130 fine sand, 130–135 ft gravel.

TM1914 9/17/2004 100 58 6 907 Shale 13 894 9/17/2004 57 850 2 0–18 till, 18–57 cemented gravel, 57–100 ft 

shale.

TM1979 3/16/2005 300 104 6 1,025.4 Shale 77.50 947.7 4/8/2005 104 921.4 0.25 0–10 S&G, 10–27 

clay & sand, 27–80 till, 80–104 S&G, 104–300 ft shale.

TM1983 4/15/2005 220 220 6 1,002 Sand 10 992 4/15/2005 -- -- 6 0–16 till, 16–26 S&G, 

26–65 till, 65–70 S&G, 70–95 fine sand, 95–185 clay, 185–204 sand, 204–220 ft sand.

TM2005 4/22/2005 30 30 6 1,002 S&G 

(confined)

 12 990 4/22/2005 -- -- 12 0–14 S&G, 14–27 till, 

27–30 ft S&G. Drawdown = 4 ft at 12 gal/min. Specific capacity = 3 gal/ft

TM2039 7/13/2005 120 120 6 847.6 Shale (and 

S&G?)

 50.40 797.18 11/1/2006 116 731.6 25 0–97 clay, 97–116 

clay & gravel (till?), 116–120 ft shale.

TM2064 8/6/2005 45 45 6 1,020 S&G 

(confined)

 15 1,005 8/6/2005 -- -- 25 0–25 S&G, 25–38 clay 

with gravel (till), 38–45 ft S&G.

TM2100 9/28/2005 220 33 6 1,025 Shale 30 995 9/29/2005 28 997 3 0–6 gravel, 6–15 clay, 

15–28 till, 28–220 ft shale.

TM2128 11/2/2005 33 33 6 960 S&G 

(unconfined)

 18 942 11/2/2005 -- -- 10 0–33 ft S&G.

TM2188 4/4/2006 150 20 6 1,085 Shale 30 1,055 4/4/2006 19 1,066 8 0–19 till, 19–150 ft 

gray shale.
54 Geohydrology of the Stratified-Drift Aquifer System, Tompkins County, New York Appendix 1 54 Appendix 1. Records of selected wells in lower Sixmile Creek and Willseyville Creek trough, Tompkins and Tioga Counties, New York. [S&G, sand and gravel; --, no data; ft, feet; dia. (in), diameter in inches; gal/min, gallons per minute; gal/ft, gallons per foot; psi, pounds per square inch; do., ditto; >, greater than] Well number Date drilled Well depth (ft) Depth of casing (ft) Casing diameter (in) Altitude land surface (ft) Aquifer type Water level below land surface (ft) Altitude water level (ft) Date water level measured Depth to bedrock (ft) Altitude top of bedrock (ft) Reported yield (gal/min) Remarks TM2269 8/30/2006 160 116 6 1,017 Shale 900 9270 8/30/2006 115 9020 0.5 0–10 gravel, 10–34 fine sand, 34–35 S&G, 35–115 silty clay, 100–115 till, 115–160 ft shale. TM2282 9/21/2006 94 26 6 1,026 Shale 160 1,0100 9/21/2006 24 1,0020 40 0–15 till, 15–24 sand and gravel. 24–94 ft shale. Spec cap. = 0.06 gal/ft. TM2311 11/10/2006 300 20 6 1,225 Shale 130 1,2210 11/13/2006 5 1,2200 1.5 0–5 till, 5–300 ft shale. TM2315 11/16/2006 40 84 6 1,016 S&G (unconfined) 260 9900 11/16/2006 -- -- 50 0–20 gravel, 20–34 fine sand, 34–42 S&G, 42–84 ft clay. Casing perforated 37–40 ft. TM2333 1/22/2007 240 24 6 1,181 Shale 720 1,1090 1/22/2007 24 1,1570 40 0–24 till, 24–160 ft grey shale. TM2355 4/4/2007 145 145 6 829 S&G (confined) Flows 8390 4/4/2007 -- -- 60 Flowing artesian well (18 psi). 0–7 till, 7–80 soft clay, 80–116 hard clay, 116–130 S&G and heaving sand, 130–143 heaving sand, 143–145 S&G. TM2360 4/24/2007 108 108 6 1,089 S&G (confined) 800 1,0090 4/24/2007 -- -- 70 0–13 hardpan, 13–18 gravel, 18–105 hard- pan and some gravel, 105–108 ft S&G. TM2367 5/21/2007 207 207 6 978 S&G (confined) 400 9380 5/21/2007 -- -- 120 0–25 S&G, 25–70 silty sand, 70–153 clay, 173–176 S&G, 176– 186 clay, 186–196 S&G, 196–205 clay, 205–207 ft S&G. TM2369 5/25/2007 240 29 6 1,215 Shale 500 1,1650 5/24/2007 28 1,1870 30 0–28 till, 28–240 ft grey shale.
Selected References 55

Appendix 1. Records of selected wells in lower Sixmile Creek and Willseyville Creek trough, Tompkins and Tioga Counties, New York. [S&G, sand and gravel; --, no data; ft, feet; dia. (in), diameter in inches; gal/min, gallons per minute; gal/ft, gallons per foot; psi, pounds per square inch; do., ditto; >, greater than]

Well 

number

Date 

drilled

Well 

depth 

(ft)

Depth 

of 

casing 

(ft)

Casing 

diameter 

(in)

Altitude 

land 

surface 

(ft)

Aquifer type

Water 

level 

below 

land 

surface 

(ft)

Altitude 

water 

level 

(ft)

Date 

water 

level 

measured

Depth 

to 

bedrock 

(ft)

Altitude 

top of 

bedrock 

(ft)

Reported 

yield 

(gal/min)

Remarks

TM2381 6/11/2007 140 60 6 1,068 Shale 300 1,0380 6/11/2007 60 1,0080 100 0–24 till, 24–25 S&G, 

25–40 till, 40–60 dirty S&G, 60–140 ft grey shale.

TM2399 7/10/2007 68 68 6 1,044 S&G 

(confined)

 300 1,0140 7/10/2007 -- -- 300 0–30 till, 30–40 S&G, 

40–52 fine to coarse sand, 52–60 S&G, 60–68 ft coarse gravel.

TM2563 8/11/2008 220 58 6 1,201.5 Shale 800 1,121.5 8/11/2008 55 1,1460 50 0–20 till, 20–40 interbedded till and clay, 

55–220 ft shale.

TM2568 8/16/2008 106 106 6 1,106 S&G 

(unconfined)

 950 1,0110 8/16/2008 -- -- 80 0–106 S&G.

TM2617 12/15/2008 200 43 6 1,062 Shale 600 1,0020 12/15/2008 43 1,0190 60 --

TM2717 11/12/2009 81 197 6 871 Sand 00 8710 11/19/2009 196 6750 200 Casing perf 72–81ft. 

0–8 S&G, 8–38 clay till?, 38–40 S&G, 40–45 till, 45–59 clay, 59–72 grav & fs, 72–88 f–ms (20 gal/min), 88–100 silty S&G or till,100–110 fs, 110–142 S&clay, 142–196 dirty grav or till, 196–216 shale (.5 gal/min) BR–salty

TI 750 6/16/1966 83 83 5 995 Sand and 

gravel

 00 -- 0 00 00 WRI 85–4127

TI 757 -- 30 30 6 968 S&G 

(unconfined)

-- -- -- -- -- -- Well in Tioga County

TI 758 30 30 6 958 Sand and 

gravel

 50 9530 -- 0 00 00
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Miller, T.S., and Karig, D.E. —Geohydrology of the Stratified-Drift Aquifer System in the Lower Sixmile Creek and Willseyville 

Creek Trough, Tompkins County, New York—Scientific Investigations Report 2010–5230

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