Prepared in cooperation with the North Carolina Department of Environment 

and Natural Resources, Division of Water Quality

Hydrogeologic Setting, Ground-Water Flow, and

Ground-Water Quality at the Langtree Peninsula

Research Station, Iredell County, North Carolina, 

2000–2005

Scientific Investigations Report 2008–5055
Cover. Left—Water-quality samples being collected (photograph by Matthew J. Heller, Virginia Department of Mines, Minerals, and Energy, 

Division of Geology and Mineral Resources) and

Right—Drilling at the Langtree Peninsula Research Station, Iredell County, North Carolina (photograph from U.S. Geological 

Survey files).
Hydrogeologic Setting, Ground-Water Flow, 

and Ground-Water Quality at the Langtree 

Peninsula Research Station, Iredell County, 

North Carolina, 2000–2005

By Charles G. Pippin, Melinda J. Chapman, Brad A. Huffman, Matthew J. Heller, 

and Melissa E. Schelgel

Prepared in cooperation with the North Carolina Department of Environment and 

Natural Resources, Division of Water Quality

Scientific Investigations Report 2008–5055

U.S. Department of the Interior

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

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

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

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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:

Pippin, C.G., Chapman, M.J., Huffman, B.A., Heller, M.J., and Schelgel, M.E., 2008, Hydrogeologic setting, groundwater flow, and ground-water quality at the Langtree Peninsula research station, Iredell County, North Carolina, 

2000–2005: U.S. Geological Survey Scientific Investigations Report 2008–5055, 89 p. (available online at 

http://pubs.water.usgs.gov/sir2008–5055)
iii

Contents

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

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

Background............................................................................................................................................2

Program Objectives..............................................................................................................................5

Purpose and Scope ..............................................................................................................................5

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

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

Acknowledgments..............................................................................................................................11

Methods of Investigation............................................................................................................................11

Research Station Design and Monitoring ......................................................................................11

Geologic Coring..........................................................................................................................11

Well-Cluster Transects and Piezometers ..............................................................................12

Well Construction ......................................................................................................................12

Investigation Field Methods..............................................................................................................12

Slug Tests ....................................................................................................................................13

Aquifer Test.................................................................................................................................13

Water-Quality Sampling............................................................................................................13

Continuous Ground-Water-Quality Monitoring.....................................................................14

Climate Data.........................................................................................................................................14

Well and Surface-Water Station Numbering System...................................................................14

Hydrogeologic Setting.................................................................................................................................15

Regional Geology................................................................................................................................15

Local Geology......................................................................................................................................16

Ground-Water System Characteristics...........................................................................................20

Regolith........................................................................................................................................20

Residuum and Saprolite...................................................................................................21

Transition Zone...........................................................................................................................22

Bedrock .......................................................................................................................................22

Ground-Water Levels .........................................................................................................................24

Seasonal Trends and Water Year Comparisons ...................................................................24

Comparison of Water Levels in Well Clusters..............................................................24

Regional Comparison .......................................................................................................28

Bedrock Ground-Water Levels................................................................................................29

Lake Stage and Ground-Water Levels ...................................................................................30

Aquifer Hydraulic Properties ............................................................................................................31

Slug Tests ....................................................................................................................................31

Aquifer Test.................................................................................................................................32

Ground-Water Flow............................................................................................................................32

Shallow Regolith ........................................................................................................................33

Transition Zone...........................................................................................................................33

Bedrock .......................................................................................................................................33

Ground-Water Quality .................................................................................................................................33

Continuous Monitoring Data.............................................................................................................37
iv

Seasonal Trends.........................................................................................................................37

Temperature.......................................................................................................................37

pH .......................................................................................................................................40

Specific Conductance......................................................................................................40

Dissolved Oxygen .............................................................................................................40

Response To Recharge .............................................................................................................40

Results from Periodic Water-Quality Sampling .............................................................................41

Ground-Water-Quality Changes with Depth..........................................................................41

Shallow Regolith Ground Water and Surface Water..................................................41

Transition-Zone Ground Water.......................................................................................47

Bedrock Ground Water....................................................................................................47

Radiochemicals and Radon Gas .............................................................................................47

Nutrients......................................................................................................................................47

Comparisons with Regional Ground-Water-Quality Data ...................................................47

Comparison of Ground-Water Chemistry to Rock Chemistry .............................................48

Summary........................................................................................................................................................48

References....................................................................................................................................................49

Appendix 1. Geologic core descriptions from the Langtree Peninsula research station

Appendix 2. Geophysical logs and images showing lithologies and fracture zones 

 tapped by bedrock wells

Figures

1. Map showing locations of research stations selected for investigations as part 

of the cooperative U.S. Geological Survey and North Carolina Division of Water 

Quality Piedmont-Mountains Resource Evaluation Program in North Carolina................2

2. Map showing locations of Langtree Peninsula research station, hydrogeologic 

units in Iredell County, and geologic belts delineated in the Blue Ridge and 

Piedmont Physiographic Provinces of North Carolina...........................................................3

3. Diagram showing conceptual components of the ground-water system in the 

North Carolina Piedmont and Blue Ridge Physiographic Provinces ...................................4

4. Diagram showing conceptual view of the slope-aquifer system and related 

compartments of the Piedmont and Blue Ridge Physiographic Provinces ........................4

5. Map showing locations of well clusters, piezometers, and lines of section at 

the Langtree Peninsula research station in Iredell County, North Carolina.......................6

6. Cross sections showing thickness of regolith, transition zone, depth to bedrock, 

and representative bedrock fractures along well transects A-A’ and B-B’ at the 

Langtree Peninsula research station, North Carolina............................................................7

7. Geologic map of sutured terranes in the Piedmont of Georgia, South Carolina, 

North Carolina, and Virginia......................................................................................................15

8. Optical televiewer image showing two foliation orientations near isoclinal folds 

and overall migmatitic structures ............................................................................................16

9. Map view of stereonet diagrams showing dip azimuth orientation of bedrock 

foliation and fractures interpreted from optical televiewer images of the open 

boreholes in bedrock wells MW-1D, -2D, -4D, -5D, and -6D at the Langtree 

Peninsula research station in Iredell County, North Carolina.............................................17
v

10. Optical televiewer image of bedrock well MW-5D showing bimodel distribution 

of foliation dip azimuth orientation and frequency of foliation orientation 

measured throughout the borehole in bedrock well MW-1D at the Langtree 

Peninsula research station, North Carolina...........................................................................18

11. Photograph of whole rock core from corehole CH-1 and optical televiewer image 

of well MW-1D showing examples of alternating fine- and medium-grained texture 

in the quartz diorite bedrock at the Langtree Peninsula research station, 

North Carolina .............................................................................................................................19

12. Optical televiewer image of bedrock well MW-5D showing a typical stress-relief 

fracture and a parting plane fracture parallel to foliation and in contact with an 

overlying granitic dike at the Langtree Peninsula research station, North Carolina......20

13. Photographed core samples from corehole CH-5 near well cluster MW-4 at the 

Langtree Peninsula research station, North Carolina..........................................................21

14. Diagram showing primary and secondary fracture network between bedrock 

wells MW-1D, -4D, -5D, and -6D at the Langtree Peninsula research station, 

North Carolina .............................................................................................................................23

15–22. Graphs showing:

15. Periodic ground-water levels recorded in all piezometers at the Langtree 

Peninsula research station, North Carolina, and monthly rainfall recorded 

at USGS station CRN-42, September 2000 through September 2005......................25

16. Periodic ground-water levels recorded in well clusters MW-1, MW-2, 

MW-3, MW-4, MW-5, and MW-6 at the Langtree Peninsula research station, 

North Carolina, January 2001 through September 2005 ...........................................26

17. Continuous hourly ground-water levels recorded in well cluster MW-2 at 

the Langtree Peninsula research station, North Carolina, overlain with 

monthly rainfall recorded at USGS station CRN-42, March 2001 through 

September 2005 ...............................................................................................................28

18. Monthly mean water levels in regolith wells DV-025 (near Mocksville, NC), 

RO-149 (Piedmont research station), and MW-2 (Langtree Peninsula 

research station) during water years 2001–05 ...........................................................29

19. Continuous ground-water levels recorded in bedrock wells MW-2D, -5D, 

and -6D, March–May 2002, and MW-1D, -2D, and -5D, July 2002, at the 

Langtree Peninsula research station, North Carolina...............................................29

20. Hourly bedrock ground-water levels and Lake Norman stage in well MW-2D, 

March 2001–December 2004, well MW-5D, December 2001–September 2002, 

and well MW-6D, March–May 9, 2002.........................................................................30

21. Hourly bedrock ground-water levels in Langtree Peninsula research station 

well MW-2D and North Carolina Department of Environment and Natural 

Resources Troutman research station well L67U2 and Lake Norman stage 

during the 2001–2002 drought........................................................................................31

22. Drawdown response of pumped well (MW-5D) and observation wells 

measured during the January 2003 aquifer test in bedrock wells and transitionzone wells at the Langtree Peninsula research station, North Carolina ...............32

23–25. Maps showing:

23. General ground-water-level altitude and flow direction in the shallow 

regolith at the Langtree Peninsula research station, North Carolina, for 

October 18, 2002, and September 23, 2003 ..................................................................34

24. Ground-water-level altitude and flow direction in the transition zone at the 

Langtree Peninsula research station, North Carolina, for October 18, 2002, 

and September 23, 2003..................................................................................................35
vi

25. Ground-water-level altitude and flow direction in the transition zone at the 

Langtree Peninsula research station, North Carolina, for October 18, 2002, 

and November 7, 2003.....................................................................................................36

26–29. Graphs showing:

26. Hourly record of ground-water levels, temperature, pH, specific conductance, 

and dissolved oxygen in well MW-2S in the shallow regolith at the Langtree 

Peninsula research station, North Carolina; and monthly rainfall data from 

Norman Shores rain gage, Lake Norman, North Carolina........................................38

27. Hourly record of ground-water levels, temperature, pH, specific conductance, 

and dissolved oxygen in well MW-2D in the bedrock at the Langtree 

Peninsula research station, North Carolina; and monthly rainfall data from 

Norman Shores rain gage, Lake Norman, North Carolina........................................39

28. Ground-water temperature recorded in shallow regolith well MW-2S in 

relation to air temperature recorded at the North Carolina State Climate 

Weather Station (2NNE) in Statesville.........................................................................40

29. Response of dissolved oxygen, pH, and specific conductance in regolith 

well MW-2S to rainfall in June and July 2003 at the Langtree Peninsula 

research station, North Carolina ..................................................................................42

30. Box plots showing range, median, and quartile statistical values for pH, 

specific conductance, and dissolved oxygen in the wells and Lake Norman 

recorded during periodic sampling events at the Langtree Peninsula research 

station, North Carolina...............................................................................................................43

31. Piper diagrams showing the distribution of major ions in periodic ground-water 

and surface-water samples from the regolith and transition-zone wells and 

Lake Norman, and open-borehole bedrock wells at the Langtree Peninsula 

research station, North Carolina..............................................................................................44

32. Stiff diagrams showing major ion milliequivalents in water samples collected 

from the regolith wells and Lake Norman, the transition-zone wells, and the 

open-borehole bedrock wells at the Langtree Peninsula research station, 

North Carolina, March 2003 ......................................................................................................45

33. Box plots showing range, median, and quartile statistical values for calcium, 

magnesium, and sodium in the wells and Lake Norman recorded during periodic 

sampling events at the Langtree Peninsula research station, North Carolina ................46

34. Box plots showing range, median, and quartile statistical values for bicarbonate, 

chloride, and sulfate in the wells and Lake Norman recorded during periodic 

sampling events at the Langtree Peninsula research station, North Carolina ................46

Tables

1. Construction characteristics of monitoring wells and the surface-water sampling 

site at the Langtree Peninsula research station in Iredell County, North Carolina...........9

2. Period of data collection for ground-water levels and water-quality measurements 

in cluster wells at the Langtree Peninsula research station, North Carolina ..................27

3. Analytical results of slug tests conducted during May 2002 and November 2003 

at the Langtree Peninsula research station, North Carolina...............................................31

4. Analyses conducted on water-quality samples collected during periodic sampling 

events at the Langtree Peninsula research station, North Carolina..................................37

5. Analytical results of arithmetic mean whole-rock core composition from three 

quartz diorite bedrock cores and arithmetic mean dissolved major ion 

concentrations in five bedrock ground-water samples collected from wells 

MW-1D and MW-2D at the Langtree Peninsula research station, North Carolina.........48
vii

Conversion Factors and Datums

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2

)

acre 0.4047 hectare (ha)

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L) 

Flow rate

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

Pressure

pound per square inch (lb/in2

) 6.895 kilopascal (kPa) 

Radioactivity

picocurie per liter (pCi/L) 0.037 becquerel per liter (Bq/L) 

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 the 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.

Abstract

A 5-year intensive field study (September 2000–

September 2005) of a complex, regolith-fractured bedrock 

ground-water system was conducted at the Langtree Peninsula 

research station on the Davidson College Lake Campus in 

Iredell County, North Carolina. This research station was 

constructed as part of the Piedmont and Mountains Resource 

Evaluation Program, a cooperative study being conducted by 

the North Carolina Department of Environment and Natural 

Resources and the U.S. Geological Survey. Results of the 

study characterize the distinction and interaction of a twocomponent ground-water system in a quartz diorite rock type. 

The Langtree Peninsula research station includes 17 monitoring wells and 12 piezometers, including 2 well transects along 

high to low topographic settings, drilled into separate parts of 

the ground-water-flow system. The location of the research 

station is representative of a metaigneous intermediate 

(composition) regional hydrogeologic unit. The primary rock 

type is mafic quartz diorite that has steeply dipping foliation. 

Primary and secondary foliations are present in the quartz 

diorite at the site, and both have an average strike of about N. 

12° E. and dip about 60° in opposite directions to the southeast 

(primary) and the northwest (secondary). This rock is cut 

by granitic dikes (intrusions) ranging in thickness from 2 to 

50 feet and having an average strike of N. 20° W. and an average dip of 66° to the southwest. Depth to consolidated bedrock 

is considered moderate to deep, ranging from about 24 to 

76 feet below land surface. The transition zone was delineated 

and described in each corehole near the well clusters but had 

a highly variable thickness ranging from about 1 to 20 feet. 

Thickness of the regolith (23 to 68 feet) and the transition zone 

do not appear to be related to topographic setting. Delineated 

bedrock fractures are dominantly low angle (possibly stress 

relief), which were observed to be open to partially open at 

depths of as much as 479 feet below land surface. Well yields 

ranged from about 3 to 50 gallons per minute. The connection 

of fracture zones at depth was demonstrated in three bedrock 

wells during a 48-hour aquifer test, and drawdown curves were 

similar for all three wells.

General findings of this study help characterize groundwater flow in the Piedmont and Mountains ground-water 

systems. Ground-water flow generally is from high to low 

topographic settings. Ground-water flow discharges toward 

a surface-water boundary (Lake Norman), and vertical 

hydraulic gradients generally are downward in recharge 

areas and upward in discharge areas. Dominant water types 

are calcium-bicarbonate and are similar in all three zones 

(regolith, transition zone, and bedrock) of the ground-water 

system. Results of continuous ground-water-quality monitoring indicate that ground-water recharge may occur seasonally 

over a period of several months or after heavy rainfall periods 

over a shorter period of a few to several weeks.

Introduction

In 1999, the U.S. Geological Survey (USGS) and the 

North Carolina Department of Environment and Natural 

Resources (NCDENR) Division of Water Quality (DWQ) 

began a multiyear cooperative study to characterize ambient 

ground-water quality and describe the ground-water-flow 

system in the Piedmont and Blue Ridge (Mountains) Physiographic Provinces in North Carolina (Daniel and Dahlen, 

2002). The study is supported by the North Carolina Piedmont 

and Mountains Resource Evaluation Program (PMREP) to 

ensure the long-term availability, sustainability, and quality of 

ground water in the State (North Carolina Division of Water 

Hydrogeologic Setting, Ground-Water Flow, and 

Ground-Water Quality at the Langtree Peninsula Research 

Station, Iredell County, North Carolina, 2000–2005

By Charles G. Pippin,1 Melinda J. Chapman,2 Brad A. Huffman,2 Matthew J. Heller,1 and Melissa E. Schelgel3

1 Formerly, North Carolina Department of Environment and Natural Resources, Division of Water Quality, Mooresville, North Carolina.

2 U.S. Geological Survey, North Carolina Water Science Center, Raleigh, North Carolina.

3 Formerly, U.S. Geological Survey, North Carolina Water Science Center, Raleigh, North Carolina.
2 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Quality, 1999). The study is planned as a 10-year intensive 

field investigation and is directed toward the establishment 

of research stations in representative geologic settings of 

the Piedmont and Mountains region of the State. To date 

(March 2008), eight research stations have been established 

and one other initiated as part of the PMREP (fig. 1).

The Langtree Peninsula research station (LPRS) is in 

Iredell County and lies within the Charlotte Belt (North 

Carolina Geological Survey (NCGS), 1985; fig. 2), which is 

representative of a foliated to massive (no foliation) quartz 

diorite geologic setting, designated as the metaigneous 

intermediate regional hydrogeologic unit (MII) by Daniel 

and Payne (1990). (This characterization differs from the 

regional map shown in figure 2, which places the study area 

in the felsic gneiss (GNF) unit.) The MII unit represents 

about 1.9 percent (Daniel and Dahlen, 2002) of the designated 

regional hydrogeologic units in the State (Daniel and Payne, 

1990). The LPRS site was selected to evaluate the effects of 

intrusive rock types having dioritic compositions on groundwater quality, thickness and composition of the regolith, 

thickness and characteristics of the transition zone, and the 

development and characteristics of bedrock fractures. Also, 

because the study area is located adjacent to Lake Norman 

(fig. 1), the largest freshwater reservoir in the State, potential 

surface-water and ground-water interactions are of interest at 

the LPRS.

Background

The Blue Ridge and Piedmont Physiographic Provinces 

in North Carolina cover approximately 30,544 square miles 

(mi2) over 65 counties (fig. 1; Daniel and Dahlen, 2002). 

In 2000, the population of the region was approximately 

6 million people (U.S. Census Bureau, 2005), of which about 

one-third were served by ground water (U.S. Geological 

Survey, 2003). 

Population concentration is near the three metropolitan 

areas of Raleigh/Durham, Greensboro/Winston-Salem, and 

Charlotte, known as the “Piedmont Crescent” (fig. 1). The 

Piedmont Crescent is described as the Nation’s fourth largest 

manufacturing region, producing $32 billion in goods in 1997 

(U.S. Census Bureau, 2004). The Charlotte area (including 

Gastonia, North Carolina, and Rock Hill, South Carolina) 

had an estimated population of about 1.3 million people in 

2000, an increase of 30 percent since 1990 (U.S. Census 

Bureau, 2005). 

In August 2000, the Langtree Peninsula area of Lake 

Norman was reported to have 5 active public supply wells 

serving 6 housing developments and approximately 390 

private wells (Heller and Rollins, 2000). The area surrounding 

the LPRS has a high percentage of urban and suburban land 

use, primarily single-family homes. 

Ground water in the Piedmont and Blue Ridge Physiographic Provinces occurs in complex hydrogeologic settings 

Figure 1. Locations of research stations selected for investigations as part of the cooperative U.S. Geological Survey and North Carolina 

Division of Water Quality Piedmont-Mountains Resource Evaluation Program in North Carolina.

2

6

Fall 

Line 

1

7 

4 

5 8

3

9

4

10

Charlotte

Mooresville

Lake

Norman

Greensboro

Raleigh

VIRGINIA 

SOUTH CAROLINA 

GEORGIA 

TENNESSEE Blue Ridge

Coastal Plain

84 

36 

35 

34 

83 82 81 80 79 78 77 76 

0 20 40 60 80 100 MILES 

0 20 40 60 80 100 KILOMETERS 

Langtree Peninsula at Lake Norman (LPRS)

North Carolina State University Lake Wheeler Road Field

 Laboratory (LWRRS)

North Carolina State University Upper Piedmont Research

 Station (UPRS)

Bent Creek Experimental Forest (BCRS)

Town of Highlands; Cullasaja Watershed

Raleigh Hydrogeologic Research Station

Allison Woods Hydrogeologic Research Station

Coweeta Hydrogeologic Research Station

North Carolina Zoological Park

 Research Station

Duke Forest Research Station

Piedmont Crescent

Physiographic Province line

Research Station and number

Well installation not completed

1 

2 9

3 10

4

5

6

7

8

Map number Research station 

EXPLANATION 

Figure 1. Locations of research stations selected for investigations as part of the cooperative U.S. Geological Survey and North Carolina Division of Water Quality

 Piedmont-Mountains Resource Evaluation Program in North Carolina.

Atlantic 

Ocean 

Piedmont

Base from digital files of: 

U.S. Department of Commerce, Bureau of Census, 

 1990 Precensus TIGER/Line Files-Political boundaries, 1991 

U.S. Environmental Protection Agency, River File 3 

U.S. Geological Survey, 1:100,000 scale 
Introduction 3

Figure 2. Locations of Langtree Peninsula research station, hydrogeologic units in Iredell County (Daniel and Payne, 1990), and 

geologic belts delineated in the Blue Ridge and Piedmont Physiographic Provinces of North Carolina (modified from North Carolina 

Geological Survey, 1985).

Base from digital files of:

U.S. Department of Commerce, Bureau of Census,

 1990 Precensus TIGER/Line Files-Political boundaries, 1991

U.S. Environmental Protection Agency, River File 3

U.S. Geological Survey, 1:100,000 scale 

SR Tr-DRB

Sauratown Mtn. ant.

SR

Tr-DCB

Tr-DRB

CS

CP

Sauratown Mountains anticlinorium

Smith River allochthon

Davie County Triassic basin

Dan River Triassic basin

Carolina Slate Belt

Western margin of Coastal Plain 

 Physiographic Province

Boundary between Blue Ridge and Piedmont

 Physiographic Provinces

Thrust fault with teeth on upthrown block

Piedmont Coastal Plain

Blue Ridge

34

35

36

84 83 82 81 80 79 78 77 76

Brevard fault zone

TENNESSEE

VIRGINIA

SOUTH CAROLINA

GEORGIA

EXPLANATION

0 25 50 75 100 MILES

0 25 50 75 100 KILOMETERS

Atlantic

Ocean

Langtree Peninsula research station

 HYDROGEOLOGIC UNITS

Gneiss, felsic (GNF)

Gneiss, mafic (GNM)

Igneous, felsic intrusive (IFI)

Igneous, mafic intrusive (IMI)

Metaigneous, felsic (MIF)

Metaigneous, intermediate (MII)

Metaigneous, mafic (MIM)

Metavolcanic, undifferentiated (MVU)

Quartzite (QTZ)

Iredell

Co.

N

Mooresville

GNF

GNM

MIF MIF

IFI

IMI

IMI

MIF

MII

MIM

MIM

MIM

MVU

QTZ

Lake

Norman

GNF

MIF

MIM MII

IFI

IFI

IFI

MIF

MVU

IFI

MVU MIM

IFI

Murphy

Belt

Blue

Ridge

Belt

Chauga

Belt

Inner

Piedmont

Belt

Charlotte

Belt

Belt

Subbasin

Tr-DCB

Kings

Mtn.

Gold Hill

shear zone

CS

Belt

Milton

Sauratown Mtn.

ant.

CP

Tr-Wadesboro

Carolina

Slate

Sanford

-Durham

CS

CP

CP

Belt

Eastern

Slate

Belt

Raleigh

EXPLANATION

Figure 2. Locations of Langtree Peninsula research station, hydrogeologic units in Iredell County (Daniel and Payne, 1990), and geologic

belts delineated in the Blue Ridge and Piedmont Physiographic Provinces of North Carolina (modified from North Carolina

Geological Survey, 1985).

0 10 20 MILES

0 8 16 KILOMETERS
4 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

composed of assemblages of metamorphic, 

igneous, and sedimentary rocks (Triassic 

basins) and secondary fracture networks. 

Weathered regolith, composed of soil, 

saprolite, alluvium, and colluvium, overlies 

the fractured bedrock (fig. 3). Piedmont 

aquifers, though simply described as a twocomponent (regolith and bedrock) groundwater system, are quite complex systems. 

The regolith, which provides storage to the 

underlying fractures in the bedrock, can be 

very heterogeneous with varying anisotropies 

and relict features, such as quartz veins and 

dikes, which substantially can alter the local 

hydraulic characteristics of the materials 

(fig. 3). A third component of the groundwater system is the transition zone, which is 

commonly present near the top of bedrock 

and typically is composed of numerous, open 

fractures in partially weathered to competent 

rock (fig. 3). The transition zone conceptually has a higher permeability compared 

to the overlying regolith and underlying 

bedrock. The characteristics of the transition 

zone and its role in the ground-water-flow 

system are being investigated as part of 

the PMREP.

Conceptual models for natural (unaffected by pumping) ground-water flow in 

the Piedmont and Mountains ground-water 

systems have been described by LeGrand (1967, 2004), 

Heath (1983, 1984), Harned and Daniel (1992), and 

Daniel and Dahlen (2002). Typically, natural groundwater recharge occurs in uplands and along slopes, while 

ground-water discharge occurs in valleys (fig. 4). 

LeGrand (2004) described the region as a slope-aquifer 

system composed of individual ground-water-flow cells 

within drainage basins. The well transects at the LPRS 

were drilled along conceptual ground-water-flow paths, 

which have both recharge and discharge areas.

Because the regolith and bedrock components of 

the ground-water system are connected, the aquifers of 

the Piedmont and Blue Ridge Physiographic Provinces 

are considered unconfined, although local confinement 

may occur in discontinuous water-bearing fracture zones 

surrounded by nearly impermeable bedrock. As the 

aquifers in these provinces usually are shallow, they 

also are susceptible to contamination by activities on 

the land surface (Daniel and Dahlen, 2002). 

Figure 3. Conceptual components of the ground-water system in the North Carolina 

Piedmont and Blue Ridge Physiographic Provinces (from Harned and Daniel, 1992).

Figure 4. Conceptual view of the slope-aquifer system and related 

compartments of the Piedmont and Blue Ridge Physiographic 

Provinces (modified from LeGrand, 2004).

SOIL 

ZONE 

Water table 

TRANSITION 

ZONE 

Regolith 

saturated 

zone 

Regolith 

unsaturated 

zone 

REGOLITH 

FRACTURED BEDROCK 

WEATHERED 

BEDROCK, 

BOULDERS 

SAPROLITE 

UNWEATHERED 

BEDROCK 

STRESS-RELIEF FRACTURE 

BEDROCK 

STRUCTURE 

FRACTURE 

Figure 3. Conceptual components of the ground-water system in the North Carolina 

 Piedmont and Blue Ridge Physiographic Provinces (from Harned and Daniel, 1992). 

Slope-aquifer boundary and

 topographic divide

Discharge boundary

Compartment (C) boundary

Water table

Fractures

Ground-water flow direction

EXPLANATION

SLOPE AQUIFER SYSTEM 

SLOPE-AQUIFER SYSTEM 

C 

C 

C 

C 

C 

C 

C 

Not to scale 

Figure 4. Conceptual view of the slope-aquifer system and related compartments of the Piedmont

 and Blue Ridge Physiographic Provinces (modified from LeGrand, 2004).
Introduction 5

Program Objectives

A primary goal of the PMREP is to develop an understanding of contaminant transport in the complex regolithfractured bedrock ground-water system in order to better 

protect and manage the resource (Chapman and others, 2005). 

Objectives of the regional PMREP are to 

1. define the hydrogeologic framework of the Blue Ridge 

and Piedmont Physiographic Provinces; 

2. identify and characterize the hydrologic processes active 

in each province; 

3. investigate the functioning of representative groundwater-flow systems in the regolith-fractured rock aquifer 

systems by means of applied research, analytical methods, 

and computer simulation; 

4. refine the present understanding of recharge and discharge 

processes and their role in determining ground- and 

surface-water quality; 

5. estimate regional water budgets, including rates of natural 

discharge and recharge; changes in aquifer storage; and 

withdrawals; 

6. determine the importance and interrelation of surface- and 

ground-water-flow systems and their effects on water 

quality and the potential for development; and 

7. develop a comprehensive ground-water database for 

the region. 

Results of this study, when combined with other studies in the 

Blue Ridge and Piedmont Physiographic Provinces of North 

Carolina and the eastern United States, will help in the management of the Nation’s water resources by defining the quality and quantity of these resources (Daniel and Dahlen, 2002). 

Purpose and Scope 

The purpose of this report is to present the results of a 

5-year study of the hydrogeologic setting, ground-water quality, and ground-water flow at the LPRS. The report includes 

descriptions of the regional surficial geology, research station 

design, well characteristics, and ground-water-level and 

ground-water-quality data. Additionally, a study of groundwater and surface-water interaction and the influence of 

Lake Norman was conducted at the site, and the results are 

reported here.

This report describes the hydrogeologic framework of 

the LPRS from field investigations conducted from September 

2000 through September 2005. The research station was 

designed to distinguish and evaluate ground water in three 

zones of the Piedmont and Mountains ground-water system—

the shallow regolith, the transition zone (partially weathered 

rock near the base of the regolith and open fractures near the 

top of bedrock), and the crystalline bedrock (characterized 

by deeper and fewer fractures; fig. 3). Components of the 

ground-water system were characterized in relation to water 

quality, hydraulic properties, and flow. 

Description of the Study Area

The LPRS is located in the Piedmont Physiographic 

Province (fig. 1), which is characterized by gently rolling hills 

and moderately well developed drainage features. The LPRS 

consists of about 10 acres on the Davidson College Lake 

Campus on Lake Norman in Iredell County, NC (figs. 2, 5). 

The research station is about 5 miles (mi) southwest of 

Mooresville, NC (fig. 1; U.S. Geological Survey, 1993). 

The site is used primarily for recreational activities, such as 

boating and swimming. Historically, the site was used for 

agricultural purposes and as a horse farm (Mr. Sterling Martin, 

Davidson College, oral commun., 2001).

The LPRS is a formerly rural area that is undergoing 

substantial population expansion and increasing dependence 

on ground-water resources for household use. The LPRS site 

was selected for study because the Davidson College Lake 

Campus is an unpopulated tract of land near the center of the 

highly populated residential developments in the Langtree 

Peninsula area of Lake Norman (fig. 5). The residents of the 

Langtree Peninsula obtain ground water either from private 

wells or one of the many community-supply wells on the 

peninsula. The conceptual hydrogeologic model of the LPRS 

is representative of larger areas in the Charlotte Belt (fig. 2) 

and the North Carolina Piedmont (fig. 1). 

According to Daniel and Payne (1990), the LPRS 

is located in the GNF (felsic gneiss) unit (fig. 2). Local 

complexities in the geologic setting can be missed in regional 

maps, however, and bedrock core collected at the LPRS 

dominantly is a quartz diorite rock type, which is part of the 

metaigneous intermediate rocks (MII) hydrogeologic unit 

described as gray to greenish-gray medium- to coarse-grained, 

massive to foliated, well-jointed, metamorphosed bodies of 

dioritic composition (Daniel and Payne, 1990). 

Rock types composing the Charlotte Belt (fig. 2) generally are of plutonic igneous origin, having a range of silicic to 

mafic compositions, with local occurrences of extrusive rock 

bodies. Most of the Charlotte Belt has been metamorphosed 

to amphibolite facies as part of a Barrovian-type regional 

metamorphic suite. 

The LPRS consists of 6 ground-water-quality monitoringwell clusters, each containing 2 to 3 wells completed in the 

regolith, transition zone, and bedrock; and 12 piezometers 

completed in the shallow regolith (fig. 5; table 1). Seven 

continuous soil and bedrock coreholes also were collected at 

the site. The topography at the LPRS resembles a northwesttrending spur that juts into Lake Norman (fig. 5). Two well 
6 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Figure 5. Locations of well clusters, piezometers, and lines of section at the Langtree Peninsula research station in Iredell County, 

North Carolina.

800 

810 

790 

790 

790 

780 

770 

780 

780 

770 

Figure 5. Locations of well clusters, piezometers, and lines of section at

the Langtree Peninsula research station in Iredell County, North Carolina.

A A' EXPLANATION

Cross section

Altitude of land surface above

 NAVD 88. Contour interval 10 feet

Well-cluster and number

Piezometer and number

Buildings

Lake sampling site

CRN-42 raingage (shown in aerial photograph)

Corehole and number

Water-supply wells

800 

0 200 400 FEET 

0 50 100 METERS 

Base from:

1998 photograph from Iredell County, North Carolina, GIS database

Contours 1993 USGS topographic sheet, 

Lake Norman Quadrangle, 1:24,000 scale

A' 

A 

B' 

B 

N

MW-1

cluster

MW-4

cluster

MW-5

cluster

MW-3

cluster

0 5,000 10,000 FEET 

0 1,250 2,500 METERS 

Lake Norman 

MW-6

cluster

MW-2

cluster

MW-2

GP-1

Woods

Woods 

Lake 

Norman 

Pier

GP-7

GP-6 GP-8

GP-5

WL-2

WL-1

GP-2

GP-3

GP-4

GP-1

WL-3 WL-4

790 

780 

770 

800 

800 

CH-4

CH-7

CH-6

CH-5

CH-1

CH-2

CH-3

Barn well

DAVIDSON

COMMUNITY COLLEGE

LAKE CAMPUS

Langtree

Peninsula

Work Creek 

Davidson Creek 
Introduction 7

transects and piezometer fields are positioned along the 

northwest trend of the topographic spur (A-A', figs. 5, 6A) and 

on the northeast side of the spur (B-B', figs. 5, 6B) following 

generalized flow paths from recharge to discharge areas. The 

land-surface altitude at the LPRS ranges from approximately 

813 feet (ft) to approximately 762 ft above North American 

Vertical Datum of 1988 (NAVD 88). Surface-water runoff 

drains to the northeast or north-northwest on either slope of 

the topographic spur (fig. 5). Runoff and tributary streams 

flow into Lake Norman, which at full stage is 760 ft above 

NAVD 88 (The Louis Berger Group, Inc., 2001).

Previous Studies

LeGrand and Mundorff (1952) described rock types and 

well yields in the Charlotte area. The gabbro-diorite rock characteristics are described as distinctly massive and not closely 

jointed. Of 69 wells inventoried in the diorite rock type, the 

range of reported well yields was from 0 to 75 gallons per 

minute (gal/min), with an average yield of about 14 gal/min. 

LeGrand (1954) included a description of the geology, 

well yields, and ground-water quality in Iredell County as 

part of a report on the Statesville area of North Carolina. The 

area of the LPRS was mapped as part of the gabbro-diorite 

unit that is consistent with the subsurface rock types observed 

during LeGrand’s study. LeGrand (1954) compared groundwater quality of dioritic rocks to that of granitic rocks of 

the area. Water from the diorite and hornblende gneiss rock 

types contained almost three times as much mineral matter 

in solution compared with water from the granitic rocks. 

LeGrand (1954) discussed potentially larger yields from the 

more mafic rocks from solutioning processes of fractures. The 

median concentrations of calcium, bicarbonate, and sulfate in 

the dioritic rocks were notably higher than the concentrations 

Figure 6A. Thickness of regolith, transition zone, depth to bedrock, and representative bedrock fractures along well 

transect A-A’ at the Langtree Peninsula research station, North Carolina (section location shown in fig. 5).

Open borehole

MW-3

cluster

MW-4

cluster

MW-2

cluster

4D 4IB 2S

2I

2D

Figure 6A. Thickness of regolith, transition zone, depth to bedrock, and representative bedrock fractures along well transect A-A’ at

the Langtree Peninsula research station, North Carolina (section location shown in fig. 5).

Regolith

Transition zone 

Bedrock

A A'

Vertical exaggeration = 3.1 times scale

Well

casing

Land surface

Data-collection

platform (DCP)

900

800

700

600

500

400

300

ALTITUDE, IN FEET ABOVE NAVD 88

4IA/4S

4S

4IA

0 250 500 750 1,000 FEET

0 50 100 150 200 250 METERS

3I 3S

Granitic dike

Regolith

Transition zone 

screen

N - NW S - SE

Bedrock

Primary foliation

Secondary foliation

Lake 

Fracture 

Fracture 
8 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

of these minerals in granitic rocks, supporting the conceptual 

model of increased mineral dissolution in the dioritic 

rock types. 

Heller and Rollins (2000) conducted a study of groundwater resources in the Langtree Peninsula area of Iredell 

County. The authors described an increase in the demand for 

ground-water resources and inventoried 5 community-supply 

wells and approximately 390 private wells. The well depths 

ranged from 46 to 900 ft, and the well yields ranged from 

about 10 to 150 gal/min.

Daniel and Dahlen (2002) described the overall regional 

goals and study design of the PMREP. Major ground-water 

issues and problems in the State were identified, and research 

station selection and site-characterization procedures were 

discussed. A list of applicable investigative methods also were 

presented by Daniel and Dahlen (2002).

Chapman and others (2005) presented results of a 2-year 

characterization of the Lake Wheeler Road research station 

(LWRRS), which also was constructed as part of the PMREP. 

The LWRRS is representative of a felsic gneiss having 

well-developed, steeply dipping foliation. This research station 

contained one well transect from high to low topographic 

settings. All three components of the ground-water system—

regolith, transition zone, and bedrock—were studied. Groundwater system characteristics, flow, hydraulic data, and quality 

were described for the LWRRS. Primary findings generally 

support the conceptual model of ground-water flow, with 

local variations in vertical gradients. Elevated nitrate concentrations were detected in ground water, most likely from 

historical agricultural activities in the study area. Continuous 

ground-water-quality monitoring at a well cluster located in a 

discharge area indicated upwelling of ground water from the 

transition zone into the shallow regolith following recharge 

events and a subsequent rise in the nearby surface-water 

tributary stage (Chapman and others, 2005). 

Huffman and others (2006) presented data collected 

at four PMREP research stations—Lake Wheeler Road, 

Langtree Peninsula, Upper Piedmont, and Bent Creek. The 

data included well-construction characteristics for 110 wells, 

periodic ground-water levels for 96 wells, borehole geophysiFigure 6B. Thickness of regolith, transition zone, depth to bedrock, and representative bedrock fractures along well 

transect B-B’ at the Langtree Peninsula research station, North Carolina (section location shown in fig. 5).

Open borehole

MW-6

cluster

MW-5

cluster

MW-4

cluster

MW-1

cluster

210 feet

total depth

B B'

Vertical exaggeration = 1.6 times scale

Well casing 6IB Land surface 6D 6S

5D5I 5S

4D

4IB 1S 1D 1I

0 100 200 300 400 FEET

0 20 40 60 80 100 METERS

GP-3

ALTITUDE, IN FEET ABOVE NAVD 88

GP-1

4IA/4S

4S

Lake 

Transition zone

Screen

4IA

900

800

700

600

500

400

300

Secondary foliation

Primary foliation

Bedrock

Granitic dike

Regolith

Break in section

Fracture 

N S

Granitic dike

Figure 6B. Thickness of regolith, transition zone, depth to bedrock, and representative bedrock fractures along well transect B-B’ at

the Langtree Peninsula research station, North Carolina (section location shown in fig. 5).
Introduction 

9

Table 1. Construction characteristics of monitoring wells and the surface-water sampling site at the Langtree Peninsula research station in Iredell County, North Carolina. — Continued [NAVD 1988, North American Vertical Datum of 1988; MW, monitoring well; S, shallow regolith; I, transition zone; D, deep; GP or WL, piezometer; IR, Iredell County; PVC, polyvinyl chloride casing; R, shallow regolith; B, bedrock; SW, surface-water site; na, not applicable; nr, not reported]

Site 

identification

Station 

name

County 

number

Construction date

Altitude

(feet 

above 

NAVD 

1988)

Well 

depth

(feet 

below 

land 

surface)

Casing 

depth

(feet 

below 

land 

surface)

Casing 

material

Casing 

diameter

(inches)

Screened interval 

or open borehole 

interval

(feet) Screen type

Zone 

monitored

Yield 

(gallons 

per 

minute) from to

353141080524701 MW-1S IR-145 10/17/2000 812.57 38 28 PVC 4.0 28 38 0.01 slotted PVC R na353141080524702 MW-1I IR-146 10/11/2000 812.65 53 38 PVC 4.0 38 53 0.01 slotted PVC I na353141080524703 MW-1D IR-147 11/13/2000 812.51 602 76 PVC 6 with 

4-inch linera

55.5/76 602 Open Hole B 50b

353135080524201 MW-2S IR-130 12/13/2000 803.08 28 13 PVC 4.0 13 28 0.01 slotted PVC R na353135080524202 MW-2I IR-131 12/13/2000 802.89 48 33 PVC 4.0 33 48 0.01 slotted PVC I na353135080524203 MW-2D IR-132 11/13/2000 802.69 400 53 PVC 6.0 53 400 Open Hole B nr353157080525301 MW-3S IR-148 1/24/2001 761.96 20 5 PVC 4.0 5 15 0.01 slotted PVC R na353157080525302 MW-3I IR-149 1/24/2001 762.92 73 43 PVC 4.0 43 73 0.01 slotted PVC I na353157080525303 MW-3Dc IR-150 1/23/2001 762.62 400 90 PVC 6.0 90 400 Open Hole B 3353145080524702 MW-4Sd IR-152 3/27/2001 802.39 38 23 PVC 2.0 23 38 0.01 slotted PVC R na353145080524701 MW-4IB IR-151 3/26/2001 802.93 53 38 PVC 4.0 38 53 0.01 slotted PVC I na353145080524704 MW-4IA IR-152A 2/26/2002 802.39 55 40 PVC 2.0 40 55 0.01 slotted PVC I na353145080524703 MW-4D IR-153 3/14/2001 801.84 400 69 PVC 6 with 

4-inch linera

69 400 Open Hole B 5b

353148080524701 MW-5S IR-154 3/27/2001 786.18 20 10 PVC 4.0 10 20 0.01 slotted PVC R na353148080524702 MW-5I IR-155 3/27/2001 785.07 35 20 PVC 4.0 20 35 0.01 slotted PVC I na353148080524703 MW-5D IR-156 3/7/2001 784.73 400 40 PVC 6.0 40 400 Open Hole B 20353151080524601 MW-6S IR-157 3/28/2001 765.32 18 8 PVC 4.0 8 18 0.01 slotted PVC R na353151080524602 MW-6Ie IR-158 4/2/2001 764.59 35 20 PVC 4.0 20 35 0.01 slotted PVC I na353151080524604 MW-6I B IR-160 3/4/2002 765.73 30 15 PVC 4.0 15 30 0.01 slotted PVC I na353151080524603 MW-6D IR-159 2/27/2001 765.84 400 69 PVC 6 with 

4-inch linera

69 400 Open Hole B 35b
10 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005 Table 1. Construction characteristics of monitoring wells and the surface-water sampling site at the Langtree Peninsula research station in Iredell County, North Carolina. — Continued [NAVD 1988, North American Vertical Datum of 1988; MW, monitoring well; S, shallow regolith; I, transition zone; D, deep; GP or WL, piezometer; IR, Iredell County; PVC, polyvinyl chloride casing; R, shallow regolith; B, bedrock; SW, surface-water site; na, not applicable; nr, not reported] Site identification Station name County number Construc- tion date Altitude (feet above NAVD 1988) Well depth (feet below land surface) Casing depth (feet below land surface) Casing material Casing diameter (inches) Screened interval or open borehole interval (feet) Screen type Zone moni- tored Yield (gallons per minute) from to 353144080524601 GP-1 IR-133 9/13/2000 805.10 38.5 29.5 PVC 0.5 29.5 38.5 0.01 slotted PVC

R na

353148080524901 GP-2 IR-134 9/21/2000 793.48 36 27 PVC 0.5 27 36 0.01 slotted PVC

R na

353146080524601 GP-3 IR-135 10/3/2000 791.04 31 22 PVC 0.5 22 31 0.01 slotted PVC

R na

353145080524401 GP-4 IR-136 9/19/2000 793.08 34 25 PVC 0.5 25 34 0.01 slotted PVC

R na

353149080524801 GP-5 IR-137 10/3/2000 786.81 32 23 PVC 0.5 23 32 0.01 slotted PVC

R na

353150080524701 GP-6 IR-138 10/4/2000 776.58 25 16 PVC 0.5 16 25 0.01 slotted PVC

R na

353151080524701 GP-7 IR-139 10/4/2000 767.37 18 9 PVC 0.5 9 18 0.01 slotted PVC

R na

353151080524501 GP-8 IR-140 10/10/2000 768.04 18 8 PVC 0.5 8 18 0.01 slotted PVC

R na

353147080524401 WL-1 IR-141 10/10/2000 784.27 35 20 PVC 1.0 20 30 0.01 slotted PVC

R na

353148080524601 WL-2 IR-142 10/9/2000 780.74 26 16 PVC 1.0 16 26 0.01 slotted PVC

R na

353150080524501 WL-3 IR-143 10/10/2000 770.46 20 10 PVC 1.0 10 20 0.01 slotted PVC

R na

353149080524401 WL-4 IR-144 10/10/2000 775.85 30 17 PVC 1.0 17 26 0.01 slotted PVC

R na

0214262175 Lake Norman (Work 

Creek arm) near Mount Mourne, NC

762.18 na na na na na na na SW na

a Four-inch liner installed in December 2001.b Initial well yield prior to 4-inch liner installation.c Abandoned in March 2002.d Well drilled deeper in February 2002 and renamed MW-4IA.e Well drilled deeper in February 2002 and renamed MW-6IB.
Methods of Investigation 11

cal logs for 23 wells, hourly ground-water levels for 12 wells, 

continuous stage for 2 streams, continuous water-quality 

measurements for 8 wells and 2 streams, periodic waterquality measurements for 58 wells and 6 stream sites, slug-test 

results for 48 wells, and shallow ground-water-flow maps. 

In addition, the geology and hydrogeology at each research 

station were described.

Results of two regional studies of ground-water quality 

in the Piedmont and Mountains region of North Carolina 

were presented by Reid (1993) and Briel (1997). Reid (1993) 

presented the results of the National Uranium Resource 

Evaluation (NURE) Program in which ground-water samples 

from 5,778 wells in North Carolina were analyzed for uranium, vanadium, dysprosium, sodium, aluminum, manganese, 

bromide, chloride, and fluoride. Briel (1997) summarized 

ground-water quality from wells in North Carolina as part of 

the Appalachian Valleys-Piedmont Regional Aquifer System 

Analysis (APRASA) study.

Acknowledgments

The authors graciously thank Sterling Martin, site 

manager, and Davidson College for permission and facilitation 

of site access to establish and conduct studies at the LPRS. 

The authors also thank the well drillers with the NCDENR 

Aquifer Protection Section for their hard work, perseverance, 

and patience in dealing with adverse conditions in the field and 

their willingness to do whatever was necessary to complete the 

work. Assistance from DWQ PMREP hydrogeologists Donald 

J. Geddes, Jr., Richard E. Bolich, Ted R. Campbell, and USGS 

hydrographer Cassandra Pfeifle is greatly appreciated. The use 

of “FracView” software from Paul Hsieh (USGS, Menlo Park, 

CA), was used to visualize the three-dimensional fracture 

network. Cartographic assistance from students Ashley 

Evans (North Carolina State University) and Erik Gulbranson 

(University of Minnesota) is greatly appreciated. The foundation for this study was established by previous work of retired 

USGS ground-water hydrologists Charles Daniel, Ralph 

Heath, and Harry LeGrand, and their contributions to the 

science of Piedmont and Mountains ground-water hydrology. 

The authors value ongoing technical discussions with these 

renowned scientists.

Methods of Investigation

Most of the methods used at the LPRS are summarized in 

Chapman and others (2005) and in standard operating procedures (SOP) for the PMREP study (Richard E. Bolich, North 

Carolina Department of Environment and Natural Resources, 

Division of Water Quality, written commun., 2008). More 

specific details of methods applied during this study, however, 

are discussed here.

Research Station Design and Monitoring

The topography in the vicinity of the well transects at 

the LPRS slopes gently toward Lake Norman and a draw to 

the east (fig. 5). The land-surface altitude along the transects 

ranges from approximately 803 ft above NAVD 88 at well 

cluster MW-2 to approximately 762 ft at well cluster MW-3, 

and from approximately 813 ft above NAVD 88 at well cluster 

MW-1 to approximately 765 ft at well cluster MW-6 (table 1). 

The LPRS consists of 6 ground-water-quality monitoring-well 

clusters constructed along 2 topographic transects, and 12 

shallow piezometers installed in a grid pattern surrounding 3 

well clusters (fig. 5). The two well transects are located along 

a high to low topographic profile, similar to that described 

by LeGrand (2004) as a “slope-aquifer” system (fig. 4), from 

recharge to discharge areas (figs. 6A, 6B). Each well cluster at 

the LPRS consists of two to three monitoring wells—a shallow 

well completed in the regolith, an intermediate well completed 

in the transition zone, and a deep bedrock well completed in 

the underlying fractured bedrock. The bedrock well associated 

with cluster MW-3 was abandoned in March 2002 because of 

collapse in the open borehole following its completion. 

Geologic Coring

Prior to well construction, continuous soil and bedrock 

cores were collected at each well-cluster location and at a 

location south of well cluster MW-2. The coreholes at these 

locations were designated CH-1, CH-2, CH-3, CH-4, CH-5, 

CH-6, and CH-7 (fig. 5). Data from the coreholes were used 

to determine construction design for the monitoring wells and 

to describe geologic materials within the ground-water system 

(app. 1). 

The coreholes were drilled using State-owned equipment 

consisting of a wire-line coring rig and a 5-ft long, 2.5-inch 

core barrel (2.5-inch inner diameter), as described in Chapman 

and others (2005). The site hydrogeologist logged each core 

upon retrieval from the sample barrel, noting soil characteristics and properties, rock type, fracture type and orientation, 

weathering, and any significant geologic features. Detailed 

Ground-water sampling equipment.
12 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

descriptions of regolith materials, including saprolite and 

bedrock lithology and fracture characteristics, are provided in 

appendix 1 of this report. Guidelines for core descriptions are 

discussed in the SOP for the PMREP (North Carolina Department of Environment and Natural Resources, Division of 

Water Quality, and U.S. Geological Survey, Water Resources 

Division, 2002). The coreholes were abandoned later in 

accordance with the State of North Carolina Subchapter 2C, 

Well Construction Standards (North Carolina Department 

of Environment and Natural Resources, Division of Water 

Quality, 2002).

Well-Cluster Transects and Piezometers

Criteria for determining well-cluster locations included 

topographic position, accessibility, and site boundaries. 

During this investigation, 18 wells and 12 piezometers initially 

were installed at the LPRS (fig. 5; table 1). Conceptual 

hydrogeologic cross sections were constructed along the well 

transects. Transect A-A' (figs. 5, 6A) extends from well cluster 

MW-2 (recharge area) to MW-3 (discharge area), and transect 

B-B' (figs. 5, 6B) extends from well cluster MW-1 (recharge 

area) to cluster MW-6 (discharge area). The piezometers 

were installed near well clusters MW-4, MW-5, and MW-6 

to determine the direction of lateral ground-water flow in the 

shallow regolith. 

Well Construction

Monitoring wells at the LPRS were constructed by using 

air-rotary, mud-rotary, hollow-stem auger, and direct-push 

drilling methods. Air-rotary drilling methods were used to 

construct the shallow regolith (MW-_S) wells and intermediate 

depth (MW-_I) transition-zone wells. For the bedrock 

(MW-_D) wells, mud-rotary methods were used to install 

the surface casing, and the open-borehole section was drilled 

by using air-rotary methods. Hollow-stem auger techniques 

were used to construct the four shallow regolith (WL-_) 

piezometers (table 1). Direct-push drilling methods were used 

to install a grid of eight shallow (GP-_) piezometers (table 1) 

tapping the regolith. Mud-rotary, air-rotary, and hollow-stem 

auger drilling methods, and well-completion techniques used 

at the LPRS were similar to those described in Chapman and 

others (2005). Screened wells generally were completed by 

using coarse sand as a filter across the screened interval and 

up to 2 ft above the top of the screen. At least 2 ft of bentonite 

sealing material then was placed on top of the sand (sediment) 

filter pack, and the remainder of the well annulus was grouted 

by using cement to land surface. Specific well-construction 

details for each well are listed in table 1. Completion problems 

occurred in bedrock wells MW-3D, MW-1D, MW-4D, and 

MW-6D when sediment collapsed into the open borehole. Well 

MW-3D was abandoned, and 4-inch polyvinyl chloride (PVC) 

liners were installed in wells MW-1D, MW-4D, and MW-6D 

(table 1). Additional sediment problems in wells MW-4S and 

MW-6I resulted in deeper drilling of well MW-4S (renamed 

MW-4IA) and the replacement of well MW-6I (new well 

MW-6IB) (table 1). 

 All wells were developed after completion in order to 

remove drilling fluids and improve hydraulic communication 

between the wells and the aquifer. Submersible pumps and 

surge blocks were used to develop the regolith and transitionzone wells, and the bedrock wells were developed by using 

air lift from the drill rig. All of the wells installed during this 

investigation were completed with a locking, steel, protector 

casing with keyed padlocks. 

Investigative Field Methods

Methods of investigation at the LPRS included borehole 

geophysical logging, optical televiewer (OTV) imaging, 

continuous ground-water-level and ground-water-quality 

monitoring (1-hour (hr) intervals), periodic ground-water-level 

measurements, ground-water-quality sampling, slug tests, and 

aquifer tests. Borehole geophysical logs run in all bedrock 

wells included the collection of caliper, electrical resistivity, 

natural gamma, temperature, fluid resistivity, and heat-pulse 

flowmeter logs. In addition, OTV images were collected to 

determine orientations of foliation and fractures (Chapman 

and others, 2005).

In this report, continuous near real-time (transmitted 

every 4 hrs) ground-water levels recorded at well cluster 

MW-2 (figs. 5, 6A; wells MW-2S, MW-2I, and MW-2D) are 

presented from March 2001 through September 2005. 

Water-level instrumentation consisted of a float-tape encoder 

system. Continuous ground-water-quality monitoring of 

temperature, pH, specific conductance (SC), and dissolved 

oxygen (DO) was conducted in regolith well MW-2S from 

August 2002 through July 2003 and in bedrock well MW-2D 

Ground-water-level monitoring equipment being installed at 

well cluster MW-2 (photograph by Stephen Howe, retired, 

U.S. Geological Survey).
Methods of Investigation 13

from August 2002 through March 2004. Water-quality monitors were set within the screened interval of 13 to 28 ft for 

regolith well MW-2S and near a fracture at about 73 ft below 

land surface in bedrock well MW-2D. Periodic ground-water 

levels were measured in all 17 wells and 12 piezometers at 

monthly intervals. Ground-water-quality samples were collected from all 17 wells and Lake Norman in August 2002 and 

March 2003. Data from one well sampled in June 2004 also 

are presented in this report. Quality-assurance procedures for 

these methods of investigation are discussed and referenced 

in Chapman and others (2005) and in the SOP for the PMREP 

study (North Carolina Department of Environment and Natural 

Resources, Division of Water Quality, and U.S. Geological 

Survey, Water Resources Division, 2002). 

Slug Tests

Slug tests were performed on eight wells at the LPRS 

to assess the horizontal hydraulic conductivity at the site. A 

5-ft long, 3-inch diameter PVC bailer was used as the slug to 

displace water inside the wells. The PVC slug was cleaned 

before use in each well. A 15-pounds-per-square-inch (psi) 

pressure transducer was used to measure water-level fluctuations during each test. The pressure transducer also contained 

an integrated electronic data logger, which was used to provide 

backup data-recording capability. 

After the slug was inserted and the water level in each 

well stabilized (after the bailer had filled with water), the slug 

was removed as quickly as possible. The rising-head slug 

test was conducted by initiating a new logarithmic recording 

step on the data logger simultaneously with the removal of 

the PVC slug. The data were field checked using hand-held 

water-level readings, and the test was terminated after water 

levels recovered to within 95 percent of the pre-test level.

The slug-test data were analyzed using the Bouwer and 

Rice (1976) method, which accounts for partial-penetration 

effects and changing aquifer thickness (water-table conditions). A basic assumption of this analytical method is that the 

aquifer is representative of a porous medium and is considered 

isotropic, having no directional variation in hydraulic properties within the zone being tested. Additional assumptions are 

that the effects of elastic storage can be neglected, and the 

position of the water table does not change during the slug 

test (Butler, 1998). The Bouwer and Rice (1976) analytical 

solution is widely used for slug-test analyses. Spreadsheets 

developed by Halford and Kuniansky (2002) were used for 

analytical interpretations of the slug-test data. The combined 

thickness of the regolith and transition zones at each well 

cluster (app. 1) was used for the total aquifer thickness for 

slug-test analyses of the wells. Thickness of the fractured 

bedrock part of the aquifer was assumed to be equal to the 

length of open borehole. 

Aquifer Test

Step-drawdown and constant-rate aquifer tests were 

conducted in January 2003 to obtain an estimate of the 

transmissivity and storage coefficients for the bedrock part 

of the aquifer. A variable-speed, 4-inch diameter, one-half 

horsepower electric submersible pump was installed in well 

MW-5D (figs. 5, 6B) at a depth of about 196 ft. The pump was 

supported by 1.25-inch inner diameter schedule-80 PVC pipe, 

and a 1.5-inch diameter polyethylene hose was used as a discharge line. A digital, in-line flowmeter was used to estimate 

pump-discharge rates. The flow rates were verified manually 

using a graduated 5-gallon (gal) bucket and stopwatch. The 

pump discharge was directed through a polyethylene hose 

into an adjacent drainage approximately 300 ft east of the 

pumped well. 

A step-drawdown test was first conducted on January 7, 

2003, for 3 hours at rates ranging from about 6 to 

14 gal/min. The results of the step-drawdown test indicated 

that the optimum pumping rate for the constant-rate discharge 

test was approximately 12 gal/min. A 48-hr constant-rate 

aquifer test was conducted January 14–16, 2003, at a rate of 

12 gal/min; approximately 34,296 gal of ground water was 

pumped from well MW-5D. Discharge from the pumped 

well was sampled periodically for selected major ions and 

monitored for pH, SC, and temperature.

During the MW-5D January 2003 aquifer test, the following wells and piezometers were instrumented with electronic 

pressure transducers to monitor water levels: MW-1I, MW-1D, 

MW-4I, MW-4D, MW-5I, MW-5D, MW-6I, MW-6D, WL-2 

and WL-3 (figs. 5, 6). Tape downs also were recorded in the 

Davidson campus barn well (fig. 5). The pressure transducers 

were placed in the designated observation wells several days 

before the start of the pumping test in order to allow time 

for the transducers to stabilize and to monitor background 

water-level fluctuations. The remaining shallow regolith wells 

and piezometers that were not instrumented were manually 

measured at regular intervals throughout the aquifer test. 

Pressure transducers near the pumped well were set initially 

to record water levels at logarithmic time intervals and 

subsequently at 10-minute intervals for the duration of the test. 

Water levels in the MW-2 well cluster were recorded at hourly 

intervals using a float/encoder/data-logger configuration and 

transmitted by satellite telemetry to the USGS National Water 

Information System (NWIS) database.

Water-Quality Sampling

Water-quality samples were collected for laboratory 

analyses from the LPRS well clusters and from Lake Norman 

in August 2002 and March 2003, and from one well that was 

sampled in June 2004. All samples were analyzed at the USGS 
14 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

National Water Quality Laboratory in Denver, Colorado. 

Additional sampling was conducted at all LPRS wells by 

DWQ personnel (Joju Abraham, North Carolina Department 

of Environment and Natural Resources, Division of Water 

Quality, Mooresville Regional Office, oral commun., 2007), 

but those data are not presented here. Sampling methods 

included the use of variable-speed, submersible 2-inch pumps; 

smaller submersible plastic, single-speed pumps; peristaltic 

pumps; and disposable bailers. Water-quality characteristics 

(pH, SC, DO, and temperature) were monitored continuously 

as water was pumped from the wells and at specific depth 

intervals in the lake. For the regolith and transition-zone well 

samples, at least three well volumes of ground water were 

pumped prior to sample collection. Stabilization of waterquality characteristics (temperature, pH, SC, and DO) was a 

requirement prior to sampling all wells (Chapman and others, 

2005). Ground-water samples were compared with whole-rock 

analyses of core that were analyzed by the USGS laboratory in 

Reston, Virginia.

For the deep, 6-inch diameter, open-borehole bedrock 

wells, the extraction of three volumes of ground water prior to 

sample collection was impractical using the low-rate sampling 

pumps. Therefore, one volume of surface casing water was 

removed at a minimum, and stabilization of water-quality 

characteristics was obtained prior to sample collection. 

In addition, the sampling pump was placed near the more 

dominant fracture zones at depth to obtain a representative 

sample (Chapman and others, 2005). 

Continuous Ground-Water-Quality Monitoring

Continuous (hourly) water-quality data were recorded 

in LPRS regolith well MW-2S during August 2002 through 

July 2003 and in bedrock well MW-2D during August 2002 

through March 2004. The purpose of collecting continuous 

ground-water-quality data was to determine seasonal fluctuations and to identify short-term fluctuations and response 

to recharge. Each well was equipped with a multiparameter 

water-quality probe for collecting temperature, pH, SC, and 

DO. The data from each water-quality probe were stored in 

an electronic data recorder and transmitted by satellite every 

4 hrs. The water-quality probes were cleaned and calibrated 

at least once a month following USGS guidelines (Wagner 

and others, 2006) and methods described in Chapman and 

others (2005). 

Climate Data

Daily rainfall data used in this report were obtained 

from the USGS Norman Shores raingage (station number 

353014080524945, CRN-42), located about 1.6 mi south of 

the LPRS (fig. 5). These data were recorded at 15-minute 

intervals and summed for the day. Records are published in 

the USGS North Carolina Water Science Center Annual Data 

Reports, accessible online at http://nc.water.usgs.gov/reports/

WDR/. Records for precipitation station CRN-42 used in 

this report are published for the water years4 2001–2005 in 

Ragland and others (2002, 2003, 2004) and Walters and others 

(2005, 2006). Daily air-temperature records were compiled 

from the Statesville 2NNE station (Ashley Frazier, Staff 

Meteorologist, State Climate Office of North Carolina, written 

commun., 2006), which is part of the North Carolina Climate 

Retrieval and Observations Network of the Southeast (CRONOS) database (North Carolina State Climate Office, 2004).

Well and Surface-Water Station 

Numbering System 

A unique identification number was assigned to each 

USGS well and surface-water station based on geographic 

location. A latitude-longitude system was used for wells, and a 

downstream-order system was used for surface-water stations. 

The latitude and longitude of each well cluster at the LPRS 

were determined by using a differential global positioning 

system (DGPS) and are considered accurate to within 5 ft. 

Wells were assigned a 15-digit site number along with 

a local number and name. The first 13 digits represent the 

latitude and longitude of each well, and these digits are 

followed by 2-digit sequence numbers that distinguish the 

wells in the well clusters. Thus, each well in a cluster has the 

same site-identification number except for the last two digits. 

Typically, the assigned sequence numbers begin with 01 for 

the shallowest well and progress with well depth. Thus, the 

deeper the well, the higher the sequence number.

In addition, the wells in this study were assigned a local 

identifier, which consists of a two-letter county code followed 

by a three-digit sequence number. For example, wells in 

Iredell County are identified by the “IR” prefix followed by 

three numbers assigned sequentially (table 1). The station 

name includes the site identifier (Langtree Peninsula research 

station), well descriptor, and number. The well descriptors 

used in this study are MW for monitoring well and WL or 

GP for piezometer. Following the well descriptor is a cluster 

number and letter, which indicates the aquifer section or 

“zone” that is being monitored: S for shallow zone in the 

regolith, I for intermediate transition zone, and D for deeper 

zone in the bedrock. For example, monitoring well MW-1S 

is located in well cluster 1 and is completed in the shallow 

regolith zone. 

The downstream order number or station number 

assigned to a surface-water station is based on the location of 

the station in the downstream direction along the main stem. 

The first 2 digits of the 8- to 10-digit station number identify 

the hydrologic unit (U.S. Geological Survey, 1974, 1975), 

which designates the major river basin in which the station 

is located. The next 6 digits indicate the downstream order 

within the river basin, and an additional 2 digits are used 

following the station number to further distinguish stations in 

areas of high station density. 

4

 Water year is the period October 1 through September 30 and is identified 

by the year in which the period ends. For example, water year 2001 began on 

October 1, 2000, and ended on September 30, 2001.
Hydrogeologic Setting 15

Figure 7. Geologic map of sutured terranes in the Piedmont of Georgia, South Carolina, 

North Carolina, and Virginia (adapted from Hibbard and others, 2002).

Hydrogeologic Setting

The hydrogeologic settings of the Piedmont and Mountains region in North Carolina are highly variable and local 

(scale of typically 1 mi or less) as a result of complex geologic 

characteristics. These geologic factors, including lithology and 

structural features, directly control ground-water flow in the 

bedrock and influence the development and characteristics of 

the shallow regolith and transition zone. A detailed description 

of the hydrogeologic setting, both at land surface and at depth, 

is needed to understand controls on flow and occurrence of 

ground water in this region. 

Regional Geology

The geologic setting of most areas in the Piedmont 

and Mountains region is complex. Rocks in this region have 

undergone intense metamorphism, folding, faulting, and 

igneous intrusion. In North Carolina, the regional sequences 

of rock bodies are grouped into “belts” (North Carolina 

Geological Survey, 1985). Although rock bodies within the 

belts generally are similar 

with regard to lithologic and 

tectonic genesis, details of 

variation and complexity are 

observed on the local scale. 

More recently, researchers 

have referred to these rock 

bodies as exotic terranes 

distinguished by varying 

characteristics attributed to 

their accretion to the Laurentian craton (Hibbard, 2000; 

Wortman and others, 2000; 

Hibbard and others, 2002). 

The works of Hibbard 

(2000), Wortman and others, 

(2000), and Hibbard and 

others (2002) describe the 

distribution and characteristics 

of various peri-Gondwanan 

exotic terranes that docked 

onto the Laurentian craton 

during the Neoproterozoic and 

early Paleozoic Eras. These 

exotic terranes, which include 

the former Kings Mountain 

Belt, Charlotte Belt, and Carolina Slate Belt, are collectively 

referred to as the Carolina 

zone (fig. 7). As a result of 

regional-style metamorphism 

across the Carolina zone, the 

metamorphic grade ranges 

from epidote-amphibolite to 

amphibolite facies. Locally occurring higher-grade rocks were 

emplaced by contact metamorphism from post-metamorphic 

igneous intrusives (Goldsmith and others, 1988). Postmetamorphic igneous intrusives are predominantly present as 

diabase and granitic dikes or as batholith-scale intrusives of 

felsic composition.

The rock assemblages that traditionally have been 

assigned to the Charlotte and Kings Mountain Belts were 

grouped by Hibbard and others (2002) into the Charlotte 

terrane (fig. 7). The Charlotte terrane is characterized mostly 

by plutonic rocks that range in age from Neoproterozoic to 

late Paleozoic and intrude a suite of mainly metaigneous rocks 

and minor metasedimentary rocks. The timing of accretion for 

the Charlotte terrane is thought to have occurred between the 

Neoproterozoic Era and early Cambrian period. By the end 

of the Ordovician period, the suturing of the Carolina terrane 

to the North American craton was completed (Hibbard and 

others, 2002). Subsequent metamorphism occurred during the 

Alleghanian Orogeny, and emplacement of dikes occurred 

across the region during Mesozoic Era extension (Butler and 

Secor, 1991; Ragland, 1991

VIRGINIA

NORTH CAROLINA

NORTH CAROLINA

SOUTH CAROLINA

Atlantic

Ocean

GEORGIA

TENNESSEE

ALABAMA

82 80 86

39

37

35

33

84 78

Albemarle- SC sequence

Cary sequence

Virgilina sequence

Spring Hope

Roanoke Rapids

Augusta

Milledgeville

Box ankle and shear zones

SUPRASTRUCTURAL

TERRANES

CAROLINA ZONE

Carolina

EXPLANATION

Charlotte

Crabtree

Raleigh

Triplet

Falls Lake

Dreher shoals

Savannah River

Uchee

Mesozoic basins

Late Paleozoic

 grantoids

INFRASTRUCTUAL

TERRANES 

Goochland

zone

Pine mountain

window

0 25 50 75 100 MILES

0 25 50 75 100 125 150 KILOMETERS

Figure 7. Geologic map of structured terranes in the Piedmont of Georgia, South Carolina, North Carolina,

 and Virginia (adapted from Hibbard and others, 2002).

Piedmont

zone

Central Piedmont

shear zone

Langtree Peninsula

research station
16 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

The LPRS lies in the central part of the Charlotte terrane 

(fig. 7; North Carolina Geological Survey, 1985; Goldsmith 

and others, 1988; Hibbard and others, 2002). The Charlotte 

terrane is characterized mostly by felsic to mafic plutonic 

rocks that range in age from Neoproterozoic to late Paleozoic 

and intrude a suite of mainly metaigneous rocks and minor 

metasedimentary rocks (Goldsmith and others, 1988; Hibbard 

and others, 2002). The various rock bodies of the Charlotte 

terrane were emplaced between 300 and 500 million years ago 

(Butler and Fullagar, 1978; Fullagar and Butler, 1979; Horton 

and Stern, 1983; Kish, 1983; Sutter and others, 1983; Goldsmith and others, 1988). Three intrusive events are responsible 

for the emplacement of the majority of the plutonic rock 

bodies that are present in the Carolina zone (Fullagar, 1971; 

Goldsmith and others, 1988). The igneous intrusives that 

compose the bedrock at the LPRS were grouped by Goldsmith 

and others (1988) with other similar rocks and designated as 

the “Older Plutonic Complex.” The older plutonic complex 

rocks generally are metamorphosed gabbros, syenites, diabase, 

granodiorite, and quartz diorites. Geochronology performed 

on zircons separated from a metagranodiorite sample collected 

in York County, South Carolina, yielded a uranium-lead 

concordia age of 532 ±15 million years (Law Engineering 

and Testing Company, 1976; Goldsmith and others, 1988). 

This age indicates that rocks of the older plutonic complex 

are related to the plutonic activity associated with the Taconic 

Orogeny. Across the Charlotte terrane (fig. 7), rock bodies that 

have undergone deformation generally can be characterized as having a subvertical foliation that trends north to 

northeast. Several post-deformation intrusive rock bodies 

are present in the Charlotte terrane as well. The regional 

metamorphic grade generally peaked at amphibolite 

facies and is considered to be related to regional metamorphism of Taconic age. 

The intensive chemical weathering of crystalline 

metamorphic and igneous rocks in the Piedmont region 

produces soil, residuum, and saprolite. Collectively, 

these materials, along with alluvium and colluvium 

(where present), compose the regolith, which overlies 

competent bedrock. Saprolite retains much of the fabric 

of the underlying parent rock. Weathering of feldspars 

and micas produces clay as residuum. As a result, soil, 

residuum, and saprolite typically have high porosity but 

low to moderate hydraulic conductivity. Ground water 

flows through intragranular pore spaces or through relict 

features, such as fractures or vein deposits, in soil and 

saprolite. In contrast, ground water in the underlying 

bedrock flows through secondary fractures and 

discontinuities because the unweathered bedrock has 

very low primary porosity and permeability. 

Daniel and Dahlen (2002) provide an overview of 

Daniel and Payne’s (1990) major hydrogeologic units of 

the Piedmont and Mountains of North Carolina. Within 

the Carolina zone, hundreds of rock units have been classified using conventional geologic nomenclature; however, 

in terms of hydraulic properties, the many units of rock 

that compose the Carolina zone have been grouped into more 

generalized hydrogeologic units (Daniel, 1989; Daniel and 

Payne, 1990). The 12 hydrogeologic units identified by Daniel 

and Payne (1990) are located in the Charlotte terrane; of 

these 12 units, the MII unit is one of the most widespread and 

represents the hydrogeologic unit that underlies the LPRS site. 

Local Geology

Based on analyses of bedrock-core samples, interpretations of downhole video logs and OTV images from the LPRS, 

and published geologic maps of the study area (Goldsmith 

and others, 1988), the shallow subsurface at the site consists 

primarily of metamorphosed quartz diorite. This rock type 

corresponds to the metamorphosed quartz diorite (mqd) and 

tonalite designation previously determined by Goldsmith 

and others (1988), which was described as “Gray, usually 

medium- to coarse-grained, generally foliated rock composed 

dominantly of plagioclase, quartz, biotite, hornblende, and 

epidote. Biotite, hornblende, and epidote are commonly 

associated in clots replacing original mafic phenocrysts.” 

These minerals may be smeared out, defining a weak foliation. 

This description is applicable to the principal rock type (quartz 

diorite) observed in the extracted core at the LPRS. In addition, localized zones of migmatitic rock are present at various 

depths, as observed in OTV images (fig. 8). Granitic dikes also 

Figure 8. Optical televiewer image showing two foliation orientations 

near isoclinal folds and overall migmatitic structures.

Fold axis

FEET BELOW LAND SURFACE

Fold axis

170

172

174

176

178

180

0 90 180 270 0

Figure 8. Optical televiewer image showing two foliation

 orientations near isoclinal folds and overall migmatitic

 structures.
Hydrogeologic Setting 17

were observed in four of the five bedrock wells, ranging in 

thickness from about 2 to 50 ft (fig. 6).

Structurally, the LPRS lies approximately 13 mi east of 

the northeast-trending Central Piedmont shear zone (fig. 7). 

Northeast-trending foliations having eastward dips, typical of 

the style of deformation commonly observed in the southern 

Appalachians, also are present in rocks underlying the site. 

Analyses of downhole OTV data collected from the bedrock 

wells at the LPRS revealed a bimodal distribution for foliation 

dip azimuths observed from individual bedrock monitoringwell boreholes (figs. 9, 10; app. 2). At least two periods of 

deformation represented by two foliation orientations were 

Figure 9. Map view of stereonet diagrams showing dip azimuth orientation of bedrock foliation and fractures interpreted from optical 

televiewer images of the open boreholes in bedrock wells MW-1D, -2D, -4D, -5D, and -6D at the Langtree Peninsula research station in 

Iredell County, North Carolina.

Figure 9. Map view of stereonet diagrams showing dip azimuth orientation of bedrock foliation and fractures

interpreted from optical televiewer images of the open boreholes in bedrock wells MW-1D, -2D, -4D, -5D, and 

-6D at the Langtree Peninsula research station in Iredell County, North Carolina.

EXPLANATION

Stereonet

Well-cluster number

 (locations shown in

 figs. 5 and 6)

0 200 400 FEET

0 50 100 METERS

Base from:

1998 photograph from Iredell County, North Carolina, GIS database

Contours 1993 USGS topographic sheet, 

Lake Norman Quadrangle, 1:24,000 scale

N

MW-1

cluster

MW-4

cluster

MW-5

cluster

Lake Norman

MW-6

cluster

MW-2

cluster

MW-2

N N

N N

Foliation Fractures

Foliation Fractures

Foliation Fractures

Foliation Fractures

N N

N N

N N

Schmidt equal-area lower

 hemisphere projection:

 darker shading of density

 contours represents a

 relatively higher concentration

 of data points per unit area.

Foliation Fractures
18 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

observed in the core and in OTV images. These two foliation 

sets have the same general strike orientations, with strike 

averaging N. 12o E., but opposite dip directions that can be 

grouped into southeast-dipping and northwest-dipping groups. 

The dip angle of both foliation groups is similar and averages 

about 60o (figs. 9, 10; app. 2). The southeast-dipping foliation 

likely is related to regional formation related to the Taconic 

Orogeny. The secondary (weaker) foliation dipping to the 

northwest may be related to regional folding. Orientation 

of the granitic dikes averages N. 20o W., dipping 66o to the 

southwest.

From the analyses of core samples, the upper (shallow) 

regolith underlying the site is primarily composed of reddish 

brown, soft to firm silty clay (CL in the Unified Soil Classification System; American Society for Testing and Materials, 

2004) to clayey silt (MH to ML; app. 1). Mica and quartz 

Figure 10. Bimodel distribution of foliation dip azimuth orientation in (A) optical televiewer 

image of bedrock well MW-5D and (B) frequency of foliation orientation measured 

throughout the borehole in bedrock well MW-1D at the Langtree Peninsula research 

station, North Carolina.

5

10

15

20

25

3025

20

15

10

5

0

FREQUENCY, IN PERCENT

0 30 90 150 210 270 330 60 120 180 240 300 360

DIP AZIMUTH, IN DEGREES

Figure 10. Bimodal distribution of foliation dip azimuth orientation in (A) optical

 televiewer image of bedrock well MW-5D and (B) frequency of foliation orientation

 measured throughout the borehole in bedrock well MW-1D at the Langtree Peninsula

 research station, North Carolina.

184

186

182

188

190

192

194

196

198

200

FEET BELOW LAND SURFACE

Primary foliation orientation

Secondary foliation orientation

A.

B.

0 90 180 270 0
Hydrogeologic Setting 19

Figure 11. Whole rock core from corehole CH-1 (location in fig. 5) and optical televiewer image of well MW-1D showing 

examples of alternating fine- and medium-grained texture in the quartz diorite bedrock at the Langtree Peninsula research 

station, North Carolina.

COREHOLE CH-1 

WELL MW-1D IMAGE

Fine-grained

texture

Medium-grained

texture

Medium-grained

texture

Enclaves

Figure 11. Whole rock core from corehole CH-1 (location in fig. 5) and optical televiewer image of well MW-1D showing

 examples of alternating fine- and medium-grained texture in the quartz diorite bedrock at the Langtree Peninsula

 research station, North Carolina.

53 feet

58 feet

122

123

124

125

126

127

128

129

Depth, in feet

below land surface 0 90 180 270 0

grains are prevalent throughout the regolith soils as are iron 

and manganese oxyhydroxide coatings on mineral grains. 

The lower regolith is composed primarily of clayey to sandy 

silt (ML) and commonly displays relict textures of the host 

material (for example, relict foliations and heterogranular 

phaneritic textures). The lower regolith is composed of 

saprolite, which grades downward to partially weathered rock 

(transition zone). Regolith thicknesses, based on auger refusals 

and core-sample descriptions, range from 23 to 68 ft in the 

down-slope well locations (well clusters MW-6 and MW-3, 

respectively, figs. 6A, 6B) and from 23 to 39 ft in the midslope and ridge hill-top well locations (well clusters MW-1, 

MW-2, MW-4, and MW-5, figs. 6A, 6B; app. 1). The transition 

zone is below the regolith and has less feldspar alteration to 

clay but includes partially weathered rock that commonly 

grades downward to competent bedrock that is characterized 

by abundant fracturing. Thickness of the transition zone ranges 

from about 1 to 20 ft.

Although the quartz diorite is the predominant rock type 

at the LPRS, occurrences of biotite hornblende gneiss, hornblende gneiss, and granitic gneiss are common. The shallowest 

bedrock typically is a medium- to fine-grained, heterogranular, 

phaneritic, quartz-hornblende, biotite-pyroxene quartz diorite. 

In corehole CH-1 (fig. 5; app. 1), the bedrock becomes more 

gneissic below about 142 ft, and foliations become steeper 

and more pronounced. This is further supported in other 

coreholes that show deformation intensifying with depth. 

Optical televiewer images recorded in bedrock wells also 

show that ductile deformation is more intense with depth and 

is characterized by steeply dipping foliations, depth-repetitive 

isoclinal recumbent folds, and local occurrences of partial 

melting (migmatite zones, including enclaves, fig. 11).

Secondary fractures in the bedrock are primarily stressrelief or exfoliation fractures formed during uplift from the 

erosion of overburden materials (fig. 12). A few fractures 

(parting plane) also were parallel to foliation (fig. 12). 

Exfoliation fractures typically have horizontal to subhorizontal 

dips. Secondary fractures were noted in core samples, OTV 

data, and in quartz-diorite boulders observed on site. Some 

of these fractures have been subject to significant dissolution 

of mineral phases, as evidenced by observations of borehole 

video logs and OTV images with productive low dip angle, 

stress-relief bedrock fractures having apertures as large as 

0.5 ft in the air-rotary borehole (MW-1D at 59 ft; app. 2). 
20 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Other fractures have a more vertical to subvertical dip and 

parallel foliation or lithologic contacts. These steeper fractures 

likely provide connectivity of the exfoliation fractures to the 

overlying saturated regolith.

Ground-Water System Characteristics

The ground-water system of the Piedmont and Mountains 

region is considered to have two primary components—the 

shallow weathered regolith and the deeper consolidated 

bedrock. Ground water occupies pore spaces in the shallow 

regolith. Directional hydraulic properties (anisotropy) also are 

possible where relict structural features, such as foliations, 

fractures, and quartz veins, are well preserved in the saprolite. 

Ground water occurs in the bedrock in secondary fractures, 

because the bedrock has little primary porosity or permeability. The regolith is considered the primary storage reservoir, 

providing recharge to the bedrock fractures (Heath, 1983, 

1984, 1991, 1994). Additionally, a transition zone commonly 

is present between the regolith and bedrock parts of the 

aquifer. The transition-zone characteristics are highly variable 

across the Piedmont and Mountains region and even across a 

smaller local area. Where measurable, the transition zone has 

an important role in the ground-water system, especially in 

terms of contaminant transport (Harned and Daniel, 1992). 

The ground-water system at the LPRS was characterized 

from interpretations of data collected in 7 coreholes, 6 well 

clusters, and 12 piezometers. The well clusters were drilled 

along topographic transects that generally follow assumed 

ground-water-flow paths from recharge to discharge areas 

(fig. 5). Detailed core descriptions are provided in appendix 1. 

Borehole geophysical logs and images are provided in 

appendix 2. Core descriptions and interpretations of geophysical logs are summarized in the following sections. 

Regolith 

The regolith is the shallow component of the Piedmont 

ground-water system and represents the weathered materials 

overlying deeper bedrock. The regolith at the LPRS is gradational in nature and includes soil, residuum, and saprolite. The 

shallow part of the regolith includes residuum, where all relict 

textures of the parent bedrock are destroyed (fig. 13). The 

shallow regolith grades into the lower regolith where relict 

bedrock features are preserved in saprolite (fig. 13). Relict 

features include structural characteristics, such as foliation, 

mineral boundaries, and vein deposits that are present in the 

lower regolith and typically grade into the transition zone 

and then to competent bedrock. The transition zone consists 

of partially weathered rock and the highly fractured upper 

bedrock. The transition into competent bedrock is recognized 

with infrequent bedrock fractures (fig. 13). Identification of 

the boundaries between these different zones can be subjective 

and requires careful observation of the extracted cores.

The physical characteristics of the regolith were recorded 

during coring and split-spoon sampling at each site. In general, 

the regolith is composed of reddish-brown clayey silt to 

silty clay with minor sand and mica, and becomes sandy silt 

with depth. Regolith characteristics, such as dry strength, 

color, moisture content, dilatancy, toughness, and plasticity, 

were determined during coring before the regolith materials 

were classified using the Unified Soil Classification System 

(American Society for Testing and Materials, 2004). In 

general, these characteristics vary substantially with increasing 

depth in the regolith—dry strength generally decreases; color 

changes from red tones to brown tones; toughness decreases; 

dilatancy generally becomes more rapid; and plasticity 

generally changes from high to moderate to non-plastic with 

Figure 12. Optical televiewer image of bedrock well MW-5D 

showing (A) a typical stress-relief fracture and (B) a parting 

plane fracture parallel to foliation and in contact with an 

overlying granitic dike at the Langtree Peninsula research 

station, North Carolina.

45

46

47

48

324

325

326

327

328

Foliation

3 inches

Foliation

Granite dike

Fracture

Quartz Dionite

Stress-relief

fracture

A. MW5D

B.

FEET BELOW LAND SURFACE FEET BELOW LAND SURFACE

Figure 12. Optical televiewer image of bedrock well MW-5D showing: (A) a typical

 stress-relief fracture and (B) a parting plane fracture parallel to foliation and in

 contact with an overlying granitic dike at the Langtree Peninsula research station,

 North Carolina.

0 90 180 270 0

0 90 180 270 0
Hydrogeologic Setting 21

increasing depth. Many of the variations observed in the 

regolith characteristics are attributed to the parent material and 

the degree of weathering. 

Residuum and Saprolite

The residuum and saprolite are part of the shallow 

regolith zone of the aquifer. The residuum generally is 

described as in-place weathered material lacking geologic 

structure. At the LPRS, the residuum is red to yellowish red, 

clayey silt to silt with minor clay and fine sand. The residuum 

typically is dry, becoming moist with depth, and is relatively 

tough with no apparent relict rock textures. The saprolite, 

formed by chemical weathering of the underlying bedrock, 

displays relict phaneritic textures, quartz veins, and some 

foliations. Kaolinite is readily observable as a weathering 

product after feldspar. The saprolite zone typically is brown to 

yellowish brown, clayey to sandy silt that grades into partially 

weathered rock. 

The thickness of the residuum and saprolite parts of the 

regolith at the LPRS do not appear to be related to topographic 

position. The thickness of the residuum at the LPRS averages 

approximately 15 ft (app. 1). The thickest residuum (27.5 ft) 

was observed at well cluster MW-1, which is in the highest 

topographic area of the research station (fig. 5). The thinnest 

residuum observed (9.5 ft) was in the core from well cluster 

MW-2 (coreholes CH-2 and CH-3, app. 1), also in a relatively 

high topographic area. Residuum thicknesses measured in 

cores from well clusters MW-3 and MW-6, located in the 

lowest topographic settings adjacent to Lake Norman, were 

11 ft and 11.5 ft, respectively (coreholes CH-4 and CH-7, 

fig. 5; app. 1). Saprolite thickness also varies substantially 

across the LPRS, averaging 22 ft. The topographic high area 

around well cluster MW-1 has the thinnest saprolite of about 

Figure 13. Core samples from corehole CH-5 near well cluster MW-4 at the Langtree Peninsula research 

station, North Carolina.

Residuum

regolith

(0 to 17.5 feet)

Figure 13. Photographed core samples from corehole CH-5 near well cluster MW-4 at the

 Langtree Peninsula research station, North Carolina.

Land surface

3 feet 33 feet

53 feet

Bedrock

(51 feet plus)

Transition zone

(39 to 51 feet)

Saprolite

(17.5 to 39 feet)
22 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

11 ft (corehole CH-1, app. 1); however, the topographic low 

area around well cluster MW-3 has the thickest saprolite of 

approximately 57 ft. At well cluster MW-6 (corehole CH-7, 

fig. 5; app. 1), another topographic low area, the saprolite 

thickness is approximately 11.5 ft. 

Six monitoring wells and 12 piezometers were installed 

in the regolith (table 1). The piezometers (GP-1–8 and 

WL1–4, fig. 5) were completed in the residuum part of the 

regolith. Each of the six well clusters includes a shallow 

well (MW-1S, -2S, -3S, -4S, -5S, and -6S) that targeted the 

saprolite zone of the regolith section of the aquifer. Monitoring 

wells MW-3S, -5S, and -6S have sections of their screens 

completed in the residuum as well. The purpose of these wells 

is to monitor water-level fluctuations and ground-water quality 

in the shallow regolith zone of the aquifer. 

Transition Zone

The transition zone between the weathered regolith 

materials (residuum and saprolite) and consolidated bedrock 

can be difficult to delineate and describe. Analyses of the 

transition-zone materials at the LPRS and at other PMREP 

research stations indicate that characteristics of the transition 

zone vary, depending on many interacting factors that include 

but are not limited to rock type, presence of systematic 

fracturing, presence of stress-relief fracturing, grain size, and 

angle and pervasiveness of foliation. The transition zone usually is composed of partially weathered rock (PWR) and(or) 

numerous open fractures near the top of bedrock. Chapman 

and others (2005) describe the transition zone in a felsic gneiss 

rock type as “partially weathered rock, having both secondary 

(fractures) and primary porosity.” At the LPRS, the transition 

zone in the quartz diorite rock type is defined similarly, having 

an upper part consisting of PWR and a lower part containing 

numerous open fractures near the top of consolidated bedrock.

From the analyses of core samples and video and OTV 

imaging, the average transition-zone thickness across the 

LPRS is approximately 12 ft (app. 1); the thickest transition 

zones (18 and 19.5 ft) were observed in corehole CH-7 and 

CH-1 near well clusters MW-6 (low topographic area near 

Lake Norman) and MW-1 (high topographic area), respectively (fig. 5). The thinnest transition zone observed in the 

cores extracted from the LPRS was in corehole CH-6 located 

at well cluster MW-5 (fig. 5). Only 1 ft of PWR was observed; 

however, solid unfractured bedrock begins at 24 ft below land 

surface at this location. 

Two bedrock wells at the LPRS tap open, shallow 

fractures that are part of the transition zone. Well MW-1D has 

an open fracture zone at a depth of 59 ft, and well MW-5D has 

an open fracture at a depth from 46 to 47 ft. Strike orientations 

of these transition-zone fractures are N. 49° E. dipping 24° SE. 

(MW-1D) and N. 17° E. dipping 10° SE. (MW-5D; app. 2). 

(The 59-ft fracture in bedrock well MW-1D was later cased 

off.) Additional shallow fractures that were not open were 

delineated at depths of 73 ft in well MW-2D; 74 ft in well 

MW-4D; and 43–44 ft, 48 ft, and 51–52 ft in well MW-6D.

Seven transition-zone wells (MW-1I, -2I, -3I, -4IA, 

-4IB, -5I, and -6I; table 1) were installed to monitor changes 

in ground-water-level fluctuations and ground-water quality 

in this part of the aquifer. Observations and identifications of 

transition-zone material were made from extracted cores near 

each well cluster (fig. 5), and screened intervals were selected 

from these descriptions. 

Bedrock 

Bedrock at the LPRS consists of igneous and metamorphic rocks of the Charlotte Belt (fig. 2; Goldsmith and 

others, 1988) and Charlotte terrane (fig. 7; Hibbard and others, 

2002). The only outcrop observed in the area (quartz diorite 

cobbles at the LPRS) is light-colored, fine- to coarse-grained 

granite, likely a member of the Churchland Plutonic Suite 

(North Carolina Geological Survey, 1985). A weak foliation 

striking N. 30° E. and dipping 80° SE. was observed in the 

granite outcrop. Non-penetrative fractures having trends of 

approximately N. 30° W., N. 45° E., N. 80° E., and N. 80° W. 

also were noted on the outcrop. Well cuttings and loose rock 

having apparent mafic compositions were observed in other 

parts of Langtree Peninsula (fig. 5 inset).

The interpretations of bedrock lithologies at the LPRS 

were based on descriptions from geologic cores and drill 

cuttings, natural gamma logs, and oriented OTV images. 

Fractures in the bedrock initially were described from the core 

samples and then characterized using caliper and resistivity 

logs, fluid resistivity and temperature logs, heat-pulse flowmeter logs, and oriented OTV images. 

The rocks underlying the site primarily are quartz diorite 

with lesser amounts of quartzofeldspathic, biotite, hornblende 

gneiss. The quartz diorite can be described generally as fineto coarse-grained, weakly foliated to massive (non-foliated) 

dark greenish-gray quartz diorite (fig. 13). The primary 

mineralogies are quartz, biotite, hornblende, and plagioclase 

feldspar with minor amounts of pyrite, epidote, and chlorite. 

(Pyrite also was observed in the OTV images.) Chlorite and 

epidote were observed commonly replacing hornblende in the 

core samples. Hornblende gneiss is the second most common 

rock type underlying the site. The primary mineralogy of 

this rock body is similar to the quartz diorite. The gneiss 

may represent localized shearing within the quartz diorite. 

Additionally, granite or granitic gneiss are present, as well 

as zones of migmatization. Evidence of migmatization is 

present at many depths (fig. 8); however, migmatization 

is more prevalent at greater depths and is evidenced by 

anastomosing patterns of light and dark mineralogies that lack 

a discernible foliation.

After the initial core collection, six open-borehole 

bedrock wells, one at each well cluster, were drilled (fig. 6).

Five of the six wells were completed to a depth of about 

400 ft below land surface, and the remaining well (MW-1D) 

was drilled to a depth of about 600 ft. Poor bedrock seals 

that allowed overlying sediment to infill from the overlying 

regolith occurred at four wells (MW-1D, -3D, -4D, and 
Hydrogeologic Setting 23

-6D). Four-inch liners were installed in these wells (table 1); 

however, well MW-3D was abandoned in March 2002 because 

of a ruptured casing that was not repairable. Depth to bedrock 

ranged from about 24 to 76 ft at the LPRS based on observations from core (figs. 6A, 6B; app. 1).

Initial well yields measured in the bedrock wells ranged 

from about 3 gal/min to more than 50 gal/min. The highest 

yielding well was MW-1D, located at the topographic high. 

The highest yield of more than 50 gal/min likely was reduced 

following the installation of a 4-inch liner (installed to about 

76 ft below land surface) that sealed off a large transition 

zone fracture at 59 ft (described in this report), just below the 

original casing depth of 55.5 ft (table 1; app. 1). 

Flow occurs within the open borehole of the bedrock 

wells, even near low-yielding fracture zones. For example, 

geophysical logs for bedrock well MW-1D indicate ambient 

(natural) inflow near depths of about 125 and 350 ft, with 

outflow between those two zones at about 225 ft (app. 2A). 

Fracture images indicate low dip angle, 10° or more 

commonly less than 5°, stress-relief fractures having a 

weathered appearance.

The bedrock underlying the LPRS has relatively 

consistent and identifiable structures. The rocks observed at 

the LPRS vary from generally or weakly massive to strongly 

foliated with increasing depth. Interpretations of foliation 

orientations from the OTV borehole images suggest that two 

deformation events may be responsible for the foliations 

observed in the core and OTV data (figs. 8, 10). Both foliations have an average strike of about N. 12°E. and dip about 

60° in opposite directions to the southeast (primary) and 

the northwest (secondary; figs. 8, 9). Foliation dip azimuth 

variations with depth are shown in appendix 2 and appear to 

be equally distributed throughout the borehole length.

Bedrock fractures, visually observed in returned core 

intervals and recorded in the borehole using OTV imaging, 

generally have horizontal to subhorizontal dip angles (stress 

relief less than 10° dip angle, fig. 12A; app. 2), and fractures 

are more frequent in the upper bedrock surface (see corehole 

descriptions in appendix 1). Other fracture orientations are 

parallel to foliation, or “parting plane” fractures (fig. 12B; 

app. 2). Because of the massive nature of the quartz diorite 

bedrock at the LPRS, parting-plane fractures and the development of permeable pathways that parallel foliation may tend to 

be reduced relative to a more foliated rock type.

The topographic drainages at the LPRS may represent 

areas of greater fracture density in the subsurface and dissolution of the diorite bedrock (LeGrand, 1952). The north-south 

trending drainage east of the bedrock well transect (MW-1D, 

-4D, -5D, and 6D, fig. 5) is similar to foliation orientation and 

foliation-parallel fractures (fig. 9; app. 2). The west-trending 

drainage west of well cluster MW-2 (fig. 5) parallels a 

secondary fracture set and subset of foliation measurements 

(at depth) striking east-west (fig. 9; app. 2).

Within the bedrock section of the aquifer at the LPRS, a 

strong degree of hydraulic connectivity was observed between 

bedrock wells MW-4D, -5D and -6D, and to a lesser extent 

MW-1D. The transect line of bedrock wells MW-4D, -5D, and 

-6D is oriented at about N. 8° E. (figs. 5, 6B), which is roughly 

parallel to the primary foliation strike N. 12° E. Fractures 

in the transition zone and at depth in wells MW-5D and 

MW-6D also have strike orientations that parallel the nearby 

drainage to the east and this well transect. Wells MW-4D 

(310 ft south-southeast), -5D, and -6D (330 ft north-northeast) 

had linear responses to bedrock pumping in well MW-5D 

(presented in a later section of this report), which indicates a 

direct connection in the three-dimensional fracture network 

underlying these wells (fig. 14). Well MW-1D, located about 

670 ft south of the pumped well, also responded to pumping 

Figure 14. Primary and secondary fracture network 

between bedrock wells MW-1D, -4D, -5D, and -6D 

at the Langtree Peninsula research station, North 

Carolina (see fig. 6 for well locations).

900

800

700

600

500

400

300

200

SSW NNE

1D

6D

5D

4D

Primary fracture orientation

 from optical televiewer image

EXPLANATION

Primary fracture orientation

 from borehole radar image

Potentially connected fracture zones

Figure 14. Primary and secondary fracture network between bedrock wells MW-1D,

 -4D, -5D, and -6D at the Langtree Peninsula research station. (See figure 6 for well

 locations.) ALTITUDE, IN FEET ABOVE NAVD 88
24 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

with a lesser magnitude of drawdown. Open (primary) fracture 

sets measured in the these bedrock wells from OTV images 

are N. 49–70° E. dipping 10–24° SE. (wells MW-1D and -4D); 

N. 17° E. dipping 10° SE. (well MW-5D); and N. 20–21° W. 

dipping 5–28° NE.-SW. (wells MW-5D and -6D). Depths of 

open to partially open fractures in wells MW-1D, -4D, -5D, 

and -6D ranged from 46.5 ft to 479 ft below land surface 

(app. 2). The lack of response in the regolith wells during the 

48-hr aquifer test indicates that little (measurable) short-term 

hydraulic connectivity occurs between the shallow regolith and 

the bedrock that immediately underlies it, or that the regolith 

has low vertical hydraulic conductivity. Recharge must occur 

from the regolith through the fracture network eventually, 

however, as the fracture network itself has little storage, as 

is evidenced by large drawdowns. For the LPRS conceptual 

model, it was assumed that recharge occurs to the fracture 

system from natural downward leakage from the overlying 

regolith and transition zone into the bedrock.

Ground-Water Levels

Periodic ground-water levels were measured monthly 

or bimonthly at the LPRS to monitor seasonal trends in the 

regolith (piezometers and MW-_S wells), transition zone 

(MW-_I wells), and bedrock (MW-_D wells; figs. 15, 16). 

Ground-water levels have been measured in the cluster wells 

since January 2001 and in the piezometers since September 

2000 (table 2). Hourly ground-water-level data have been 

recorded at all three MW-2 cluster wells (2S, 2I, and 2D) since 

March 2001 (fig. 17). Data are presented in this report through 

September 30, 2005.

Seasonal Trends and Water Year Comparisons

From September 2000 through September 2005 (complete water years (WYs) 2001–2005), water levels in wells at 

the LPRS responded to climatic conditions, including seasonal 

trends and extreme conditions, such as droughts and the stage 

of nearby Lake Norman (figs. 15–17). Generally, seasonal 

high ground-water levels occur during the spring, in response 

to winter and spring precipitation (typical recharge period 

for the Piedmont region). Ground-water levels decline as 

evapotranspiration (ET) processes increase during the spring 

and summer months, and the lowest water levels occur during 

the fall months.

Ground-water levels in the well clusters and piezometers 

responded to seasonal trends of winter/spring recharge and 

summer ET processes (figs. 15–17). Hourly ground-water 

levels recorded in well cluster MW-2 indicate seasonal 

patterns of an overall rise in water levels during the recharge 

periods and a gradual decline during the warmer summer 

months and into the fall months (fig. 17). Additionally, a 

recognizable difference in climatic conditions is evident 

in comparisons between WYs 2001 and 2002 (drought 

conditions) and WY 2003 when above-normal rainfall was 

recorded. For the study period at the LPRS, ground-water 

levels were lowest during fall 2002 (figs. 15–17) in response 

to an extended 4-year drought throughout the State (Weaver, 

2005). In contrast, above-normal rainfall occurred at the LPRS 

during WY 2003, and ground-water levels in the regolith and 

transition zone rose about 9 ft in well MW-5I and about 12 ft 

in well MW-2 (fig. 16). Rainfall totals at USGS rainfall gage 

CRN-42 (fig. 5), located about 1.6 mi south of the LPRS, 

were nearly 69 inches for WY 2003 compared with about 

28 inches for WY 2002 (Ragland and others, 2003, 2004). 

Mean annual rainfall for the period of record (1948–2006) at 

the Charlotte-Douglas Airport is 32.35 inches (North Carolina 

State Climate Office, 2004). Below-normal rainfall also was 

recorded at station CRN-42 in WY 2001 (31 inches) and WY 

2005 (35 inches), and slightly above-normal rainfall (about 

48 inches) was recorded in WY 2004. Ground-water-level 

data recorded at the LPRS wells were summarized for WYs 

2001–2005 and published in USGS annual data reports (Howe 

and others, 2002, 2003, 2004, 2005; Fine and others, 2006). 

Comparison of Water Levels in Well Clusters

Comparison of the water levels in the well clusters was 

used to qualitatively interpret the vertical gradients in the 

ground-water system. Five of the six well clusters at the LPRS 

have at least one shallow well completed in the regolith. 

The exception is cluster MW-4, which has two transition 

zone wells. All six well clusters have wells completed in the 

transition zone and deeper bedrock. 

A rise in ground-water levels in regolith well MW-2S 

rarely occurred during the summer months (except during 

the summer of 2003 in response to above-normal rainfall), 

because ET generally exceeded rates of ground-water 

recharge. Periodic ground-water levels recorded in well 

clusters MW-1, MW-4, and MW-5 (fig. 16) also showed 

seasonal and climatic trends, similar to water levels recorded 

hourly in well cluster MW-2 (fig. 17). Seasonal trends were 

less evident in well clusters MW-3 and MW-6 as a result of 

the close proximity of these wells to Lake Norman. The stage 

of Lake Norman is controlled by Cowan’s Ford Dam, which is 

used for hydroelectric power generation and is located about 

8 mi southeast of Langtree Peninsula.

Water-level altitudes in the shallow regolith and transition 

zone were similar in all well-cluster locations (both recharge 

and discharge areas) at the LPRS. Vertical gradients are 

evident when the shallow part of the ground-water system 

(regolith and transition zone) is compared to the deeper 

bedrock. In recharge or slope areas (well clusters MW-1, 

-2, -4, and -5), a downward vertical gradient was observed 

(fig. 16A, B, D, E, respectively). However, in discharge areas, 

such as the location of MW-6 (excluding abandoned bedrock 

well MW-3D, also in a discharge area), an upward vertical 

gradient from the bedrock is evident (fig. 16F). This result 

supports the historical conceptual model of the Piedmont 

ground-water system described by LeGrand (1967, 2004), 

Heath (1983, 1984), Harned and Daniel (1992), and Daniel 

and Dahlen (2002).
Hydrogeologic Setting 25

Figure 15. (A) Periodic ground-water levels recorded in all piezometers at the Langtree Peninsula research station, North Carolina, 

and (B) monthly rainfall recorded at USGS station CRN-42, September 2000 through September 2005.

Water Year

2001

Water Year

2001

Water Year

2002

Water Year

2002

Water Year

2003

Water Year

2003

Water Year

2005

Water Year

2005

Water Year

2004

Water Year

2004

WATER-LEVEL ALTITUDE, IN FEET ABOVE NAVD 88

MONTHLY RAINFALL, IN INCHES

A.

B.

S D

2001 2002 2003 2004 2005

M J S D M J S D M J S D M J S D M J S

Figure 15. (A) Periodic ground-water levels recorded in all piezometers at the Langtree Peninsula research

 station, and (B) monthly rainfall recorded at USGS station CRN-42, September 2000 through September 2005.

GP-1

GP-2

GP-3

GP-4

GP-5

GP-6

GP-7 Lake

GP-8

WL-1

WL-2

WL-3

WL-4

No measureable rainfall recorded during October 2000

12

10

8

6

4

2

0

780

775

770

765

760

755

750
26 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Figure 16. Periodic ground-water levels recorded in well clusters (A) MW-1, (B) MW-2, (C) MW-3, (D) MW-4, (E) MW-5, and (F) MW-6 

at the Langtree Peninsula research station, North Carolina, January 2001 through September 2005.

A. B.

D.

E. F.

MW-1S

MW-1I

MW-1D

MW-1D (without liner)

MW-3S

MW-3I

MW-3D

Lake (tape downs at dock)

MW-5S

MW-5I

MW-5D

MW-2S

MW-2I

MW-2D

MW-4IB

MW-4IA

MW-4D

MW-4S

MW-4D (without liner)

C.

MW-6S

MW-6IB

MW-6D

MW-6I

Lake

MW-6D (without liner)

Water Year

2002

Water Year

2003

Water Year

2004

Water Year

2005

Water Year

2002

Water Year

2003

Water Year

2004

Water Year

2005

Water Year

2002

Water Year

2003

Water Year

2004

Water Year

2005

Water Year

2002

Water Year

2003

Water Year

2004

Water Year

2005

Water Year

2002

Water Year

2003

Water Year

2004

Water Year

2005

Water Year

2002

Water Year

2003

Water Year

2004

Water Year

2005

Water Year

2001

Water Year

2001

Water Year

2001

Water Year

2001

Water Year

2001

Water Year

2001

Land surface = 812 feet Land surface = 803 feet

Land surface = 762 feet Land surface = 802 feet

Land surface = 785 feet Land surface = 765 feet

Figure 16. Periodic ground-water levels recorded in well clusters (A) MW-1, (B) MW-2, (C) MW-3, (D) MW-4, 

 (E) MW-5, and (F) MW-6 at the Langtree Peninsula research station, North Carolina, January 2001 through

 September 2005.

785

780

775

770

765

760

755

795

790

785

780

775

770

760

759

758

757

756

755

754

753

752

751

780

775

770

765

760

755

750

770

768

766

764

762

760

758

756

754

752

750

762

760

758

756

754

752

750

JAN.

APR.

JULY

OCT.

JAN.

APR.

JULY

OCT.

JAN.

APR.

JULY

OCT.

JAN.

APR.

OCT.

2001 2002 2003

JULY

2004

JAN.

APR.

JULY

OCT.

2005

JAN.

APR.

JULY

OCT.

JAN.

APR.

JULY

OCT.

JAN.

APR.

JULY

OCT.

JAN.

APR.

OCT.

2001 2002 2003

JULY

2004

JAN.

APR.

JULY

OCT.

2005

WATER-LEVEL ALTITUDE, IN FEET ABOVE NAVD 88
Hydrogeologic Setting 27

Table 2. Period of data collection for ground-water levels and water-quality measurements in cluster wells at the 

Langtree Peninsula research station, North Carolina. (End date is September 2004, unless otherwise noted.)

[MW, monitoring well; s, shallow regolith well; I, transition zone well; D, bedrock well; GP, Geoprobe well; na, not applicable]

Station name

Water-level/Stage

Water quality

(temperature, pH, specific 

conductance, and dissolved 

oxygen)

Start date periodic data

Continuous data 

start date (1-hour 

recording interval)

Continuous water-quality data 

(1-hour recording interval)

MW-1S January 2001 na na

MW-1I January 2001 na na

MW-1D January 2001 na na

MW-2S February 2001 March 2001 August 2002 discontinued 

July 2003

MW-2I February 2001 March 2001 na

MW-2D February 2001 March 2001 August 2002 discontinued 

March 2004

MW-3S February 2001 na na

MW-3I February 2001 na na

MW-3Da February 2001 discontinued 

November 2001

na na

MW-4Sb May 2001 discontinued 

March 2002

na na

MW-4I B May 2001 na na

MW-4I A March 2002 na na

MW-4D May 2001 na na

MW-5S May 2001 na na

MW-5I May 2001 na na

MW-5D May 2001 na na

MW-6S May 2001 na na

MW-6Ic May 2001 na na

MW-6I B March 2002 na na

MW-6D March 2001 na na

GP-1 September 2000 na na

GP-2 September 2000 na na

GP-3 October 2000 na na

GP-4 September 2000 na na

GP-5 October 2000 na na

GP-6 October 2000 na na

GP-7 October 2000 na na

GP-8 October 2000 na na

AUGER (WL) 1 October 2000 na na

AUGER (WL) 2 October 2000 na na

AUGER (WL) 3 October 2000 na na

AUGER (WL) 4 October 2000 na na

Lake Norman (Work Creek arm) 

near Mount Mourne, NCd

October 2000 na na

a Well abandoned in March 2002.

b

 Well drilled deeper in February 2002 and renamed MW-4I A.

c

 Well drilled deeper in February 2002 and renamed MW-6I B.

d

 Periodic staff plate reading.
28 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Figure 17. Continuous hourly ground-water levels recorded in well cluster MW-2 at the Langtree Peninsula research station, 

North Carolina, overlain with monthly rainfall recorded at USGS station CRN-42, March 2001 through September 2005.

790

788

786

784

782

780

778

776

774

772

770

WATER-LEVEL ALTITUDE, IN FEET ABOVE N

AVD 88

MONTHLY RAINFALL, IN INCHES

12

10

8

6

4

2

0

Figure 17. Continuous hourly ground-water levels recorded in well cluster MW-2 at the Langtree Peninsula

 research station, North Carolina, overlain with monthly rainfall recorded at USGS station CRN-42, March

 2001 through September 2005.

MW-2S

MW-2I

MW-2D

Rainfall from CRN-42

2001 2002 2003

WATER YEAR

2004 2005

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

Regional Comparison 

Water-level trends in regolith well MW-2S at the LPRS 

were compared with long-term water-level records for two 

regolith observation wells in the Piedmont—one in Davie 

County, NC (Mocksville well NC-142; USGS station number 

355359080331701, DV-025) and one in Rowan County, 

NC (Piedmont research station well NC-193; USGS station 

number 354057080362601, RO-149). This comparison was 

made to determine if ground-water-level data collected from 

the LPRS were representative of regional conditions. Groundwater levels at all three locations had similar seasonal and 

climatic trends for water years 2001 through 2005 (fig. 18). 

Following the drought in 2002, ground-water levels in wells 

NC-142 and NC-193 recovered to normal conditions within 

about 7 to 8 months (Howe and others, 2004). (The period 

of record for LPRS well MW-2S began in 2001 in drought 

conditions; therefore, “normal” long-term conditions have not 

yet been recorded.) Preparing to sample well cluster MW-3 near Lake Norman.
Hydrogeologic Setting 29

Bedrock Ground-Water Levels

Continuous ground-water-level data collected 

from four bedrock wells at the LPRS indicate a 

similar response in all of the wells to seasonal 

recharge and local pumping. Water-level data for 

bedrock well MW-2D indicate an overall seasonal 

correlation with shallower wells MW-2S and 

MW-2I (fig. 17) and an underlying influence from 

local pumping. Three bedrock water-supply wells 

are on the Davidson College property (fig. 5), and 

other community-supply wells are located within 

a quarter mile of the LPRS. Local pumping effects 

are recognized by sharp declines and recovery 

occurring in daily cycles. The graphs in figure 19 

illustrate the correlation of bedrock ground-water 

levels observed during short-term monitoring 

in 2002 and the influence of nearby pumping 

(Davidson College wells or community-supply 

wells).

Care should be taken in the interpretation of 

open-borehole water levels in the bedrock wells 

because the data represent a composite of the 

hydraulic heads in several fractures tapped by the 

well. The hydraulic head in a specific fracture may 

be different from that measured in the entire open 

borehole. 

Figure 18. Monthly mean water levels in regolith wells DV-025 (near Mocksville, NC), RO-149 (Piedmont research station), and MW-2 

(Langtree Peninsula research station) during water years 2001–05.

Figure 18. Monthly mean water levels in regolith wells DV-025 (near Mocksville, NC), RO-149 (Piedmont research station),

 and MW-2S (Langtree Peninsula research station) during water years 2001–05.

Water Year

2001

Water Year

2003

Water Year

2005

Water Year

2004

Water Year

2002

Langtree Peninsula research station well MW-2S

Mocksville DV-025 (NC-142)

Piedmont research station RO-149 (NC-193)

10

12

14

16

18

20

22

24

26

28

MW-1S WATER LEVEL, IN FEET BELOW LAND SURFACE

4

5

6

7

8

9

10

DV-025 WATER LEVEL, IN FEET BELOW LAND SURFACE

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

11

O N D J F

30

Figure 19. Continuous ground-water levels 

recorded in bedrock wells (A) MW-2D, -5D, and 

-6D, March–May 2002, and (B) MW-1D, -2D, and 

-5D, July 2002, at the Langtree Peninsula research 

station, North Carolina.

23.5

23.7

23.9

24.1

24.3

24.5

24.7

24.9

25.1

25.3

25.5

WATER LEVEL, IN FEET BELOW LAND SURFACE FOR MW-2D

47.5

48.0

48.5

49.0

49.5

50.0

50.5

51.0

WATER LEVEL, IN FEET BELOW LAND SURFACE FOR MW-1DWATER LEVEL, IN FEET BELOW LAND SURFACE FOR MW-2D

27.0

27.5

28.0

28.5

29.0

29.5

30.0

25.5

26.0

26.5

27.0

WATER LEVEL, IN FEET BELOW LAND SURFACE FOR MW-5D

24

25

26

27

28

29

WATER LEVEL, IN FEET BELOW LAND SURFACE FOR MW-5D

5

6

7

8

9

10

11

WATER LEVEL, IN FEET BELOW LAND SURFACE FOR MW-6D

MW-2D

MW-5D

MW-6D

MW-1D

MW-2D

MW-5D

1 5 9 13

MARCH APRIL

2002

MAY JUNE

17 21 25 29 2 6 10 14 18 22 26 30 4 8 12 16 20 24 28 1

1 2 3 4

JULY

2002

AUGUST

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1

A.

B.

Figure 19. Continuous ground-water levels recorded in bedrock wells

 (A) MW-2D, -5D, and -6D, March--May 2002, and (B) MW-1D, -2D, and

 -5D, July 2002, at the Langtree research station, North Carolina.

Influence of local

pumping

Influence of local

pumping
30 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Figure 20. Hourly bedrock ground-water levels and Lake Norman 

stage in (A) well MW-2D, March 2001–December 2004, (B) well 

MW-5D, December 2001–September 2002, and (C) well MW-6D, 

March–May 9, 2002.

762

761

760

759

758

757

756

755

754

753

752

751

791

786

781

776

771

761

760

759

758

757

756

755

754

753

752

751

761

760

759

758

757

756

755

761

760

759

758

757

756

755

754

753

752

751

761

760

759

758

757

756

755

GROUND-WATER LEVEL ALTITUDE, IN FEET ABOVE NAVD 88

LAKE-STAGE ALTITUDE, IN FEET ABOVE NAVD 88

MAR. 1,

2001

FEB. 14,

2002

JAN. 30,

2003

JAN. 15,

2004

DEC. 31,

2004

DEC. 1,

2001

JAN. 11,

2002

APR. 25,

2002

JULY 6,

2002

SEPT. 17,

2002

MAR. 1,

2002

MAR. 18,

2002

APR. 4,

2002

APR. 21,

2002

MAY 9,

2002

Lake Norman stage

Bedrock ground-water levels

 in MW-2D

A.

Lake Norman stage

Bedrock ground-water levels in MW-5D

Lake Norman stage

Bedrock ground-water levels in MW-6D

B.

C.

No data

Influence of local

pumping

Figure 20. Hourly bedrock ground-water levels in relation

 to Lake Norman stage in (A) well MW-2D, March 2001

 through December 2004, (B) well MW-5D, December

 2001 through September 2002, and (C) well MW-6D,

 March through May 9, 2002.

Lake Stage and Ground-Water Levels

The LPRS is located adjacent to Lake Norman, which 

is the largest manmade surface-water impoundment in 

North Carolina and encompasses an area of more than 

31,984 acres (50 mi2) at the full stage of 760-ft altitude 

(The Louis Berger Group, Inc., 2001). Based on periodic 

ground-water-level measurements and readings of lake 

stage using a staff plate (referenced to altitude above land 

surface), the hydraulic gradient in the shallow part of the 

ground-water system (regolith and transition zone) near 

Lake Norman is flat. Ground-water-level altitudes measured 

in wells MW-3S, MW-3I, MW-6S, MW-6I, and MW-6IB 

were within a few hundredths of a foot to 1 ft of the lake 

stage (fig. 16C, F). These wells are located within 100 ft 

of the lake shore. Additionally, piezometers GP-6, -7, and 

-8 and WL-3 and -4, located within about 300 ft of the lake 

shore, had ground-water-level altitudes that were generally 

within 1 ft of the lake-stage altitude (fig. 15). Surface water 

stored in the lake likely affects shallow ground-water levels 

near shore (lateral interactions), as is evidenced by similar 

lake altitudes and ground-water levels in the regolith and 

transition zone. At depth, however, vertical gradients in well 

cluster MW-6 are upward (fig. 16F), and the ground-waterlevel altitude is higher in the bedrock than in the regolith 

and transition zones and the lake. 

In comparing hourly stage data for Lake Norman to 

bedrock ground-water levels, the influence of the lake on 

the deeper part of the ground-water system is uncertain. For 

example, during the drought water years when releases from 

Lake Norman were less frequent because water was being 

held for storage (Bill Stroud, Duke Power Co., Charlotte, 

NC, oral commun., 2005), an overall seasonal (climatic) 

correlation for both shallow and deep ground-water-level 

data and lake stage appears to be evident (fig. 20). However, 

as lake stage rose in WY 2003 in response to increased 

rainfall, releases from Lake Norman became more frequent, 

which lowered the stage while ground-water levels 

continued to rise in bedrock well MW-2D (fig. 20A). By 

overlaying ground-water-level data from bedrock wells 

MW-5D (fig. 20B) and MW-6D (fig. 20C) during 2002 with 

lake-stage data, a drought year seasonal correlation can be 

noted with local pumping effects (underlying sharp declines 

in ground-water levels).

Bedrock ground-water levels from well MW-2D at 

the LPRS were compared with water levels recorded in a 

bedrock well at the Troutman research station (North Carolina Department of Environment and Natural Resources, 

Division of Water Resources well L67U2; fig. 21) also 

located on Lake Norman about 10 mi north of the study site. 

The water-level data from the Troutman research station 

and bedrock well MW-2D had similar seasonal patterns 

during WYs 2001 and 2002 (drought years), and both had 

a large rise during WY 2003 as a result of above-normal 

rainfall. Water-levels recorded in the Troutman bedrock well, 

however, do not appear to be affected by local pumping, as a 
Hydrogeologic Setting 31

secondary pattern similar to that recorded in LPRS 

well MW-2D was not observed. LPRS bedrock 

well MW-2D is located about 1,350 ft from Lake 

Norman, whereas the Troutman bedrock well is 

located about 400 ft from the lake.

Aquifer Hydraulic Properties

Aquifer hydraulic properties at the LPRS 

were computed by analyzing data from rising-head 

slug tests in eight wells and an aquifer test in 

bedrock well MW-5D. Slug tests are considered 

to provide estimates of the horizontal hydraulic 

conductivity of near-borehole aquifer materials. A 

step-drawdown test and a constant-rate aquifer test 

were conducted using bedrock well MW-5D as the 

pumped well. 

Slug Tests

Slug tests provide a relatively quick and 

economical method to assess spatial trends in 

horizontal hydraulic conductivity across a study 

area. These methods test near-borehole materials. 

Methods and equipment used for slug testing are 

described in the “Methods” section of this report. Slug tests 

were conducted in eight wells at the LPRS during May 2002 

and November 2003—three wells in the regolith, two in the 

transition zone, and three in the bedrock (table 3).

The slug-test data collected at the LPRS were analyzed 

using the Bouwer and Rice (1976) method, which accounts for 

water-table conditions and partial-penetration effects. For the 

shallow regolith wells and the transition zone wells, aquifer 

thickness was assumed to include both zones; the base of the 

aquifer (thickness) was considered to be the bottom of the 

transition zone. For the bedrock wells, the aquifer thickness 

was considered to be the length of open borehole, from casing 

depth to total well depth. A summary of results of the slug-test 

data analyses is given in table 3. 

Analytical results of the slug tests conducted in wells 

at the LPRS indicate hydraulic conductivities of a similar 

order of magnitude: 2 to 7 feet per day (ft/d) for the regolith, 

transition zone, and high-yield bedrock wells. A lower order 

of magnitude of hydraulic conductivities of 0.4 to 0.6 was 

measured in one transition-zone well (MW-1I, table 3) and 

bedrock well (MW-2D, table 3). 

Figure 21. Hourly bedrock ground-water levels in Langtree Peninsula 

research station well MW-2D and North Carolina Department of Environment 

and Natural Resources Troutman research station well L67U2 and Lake 

Norman stage during the 2001–2002 drought. GROUND-WATER-LEVEL ALTITUDE, IN FEET ABOVE NAVD 88

2001 2002

Figure 21. Hourly bedrock ground-water levels in Langtree Peninsula

 research station well MW-2D and North Carolina Department of

 Environment and Natural Resources Troutman research station well

 L67U2 in relation to Lake Norman stage during the 2001–2002 drought.

783

782

781

780

779

778

777

776

775

LAKE-STAGE ALTITUDE, IN FEET ABOVE NAVD 88

760

759

758

757

756

755

754

753

752

751

750 MAR.

APR.

MAY

JUNE

JULY

AUG.

SEPT.

OCT.

NOV.

MAR.

APR.

MAY

JUNE

JULY

AUG.

SEPT.

DEC.

JAN.

OCT.

NOV.

FEB.

Troutman research station well L67U2

MW-2D

Lake Norman at Cowan’s Ford Dam

Table 3. Analytical results of slug tests conducted during May 2002 and November 2003 

at the Langtree Peninsula research station, North Carolina.

[ft bls, feet below land surface; B/R, Bouwer and Rice (1976) analytical solution; k, hydraulic conductivity estimate; ft/d, feet per day; PWR, partially weathered rock; *, ground-water levels did not fully 

recover to static conditions. Note: All analyses are from rising-head slug tests]

Well number and 

ground-water zone 

tapped

Materials

Screened or 

open interval

 (ft bls)

B/R k

(ft/d) Order of 

magnitude k

MW-2S (regolith) fine sand 13–28 5 1

MW-3S (regolith) fine sand 5–15 2 1

MW-6S (regolith) fine sand 8–18 3 1

MW-1I (transition zone) PWR 38–53 0.6 0.1

MW-3I (transition zone) PWR 43–73 2 1

MW-2D (bedrock) low-yield fractures 53–400 *0.4 0.1

MW-5D (bedrock) high-yield fractures 40–400 7 1

MW-6D (bedrock) high-yield fractures 69–400 2 1
32 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Aquifer Test

A 48-hr constant-rate aquifer test was conducted to 

observe the response of the fracture network and overlying 

regolith to pumping stress. Quantitative estimates of transmissivity and storage coefficients for the bedrock were not 

possible because widely accepted analytical methods are not 

available for the complex regolith-fractured bedrock groundwater system. Equipment and procedures used in the aquifer 

test are described in the “Methods” section of this report. 

A total of 34,296 gal of ground water was pumped from 

bedrock well MW-5D during a 48-hr constant-rate aquifer 

test conducted during January 14–16, 2003. The average 

discharge rate was 12 gal/min. Several observation wells and 

piezometers were monitored during the aquifer test: MW-1I, 

MW-1D, MW-4IA, MW-4D, MW-5I, MW-5D, MW-6IB, 

MW-6D, WL-2, and WL-3 (figs. 5, 6). Hourly ground-water 

levels also were monitored in well cluster MW-2. Drawdown 

in the pumped well was about 122 ft, resulting in a calculated 

specific capacity of 0.1 gal/min per foot ([gal/min]/ft) of 

drawdown. The pumping water level was about 150 ft below 

land surface, and the two uppermost fractures at 46 and 

106 ft were dewatered; however, the deeper fractures in 

bedrock well MW-5D at 171 ft (app. 2) likely continued to 

supply water to the well during 

the aquifer test. 

Several bedrock wells had 

measured drawdown during 

the January 2003 aquifer test 

in well MW-5D at the LPRS. 

The three bedrock wells that 

were known to tap the same 

fracture network— pumped 

well MW-5D and observation 

wells MW-6D (360 ft from 

the pumped well) and MW-4D 

(290 ft from the pumped well; 

fig. 6B)—all exhibited similar 

responses to pumping (fig. 22A) 

and had a total drawdown greater 

than 100 ft. Observation well 

MW-6D appears to be more 

closely connected to the pumped 

well by having nearly the 

same magnitude of drawdown 

characteristics throughout the 

aquifer test. Compared to well 

MW-4D, well MW-6D had more 

open fractures. Additionally, 

bedrock wells MW-1D (about 

690 ft away) and the Davidson 

College campus barn well (about 

1,000 ft away) had measurable 

drawdowns of about 20 ft and 

4 ft, respectively (fig. 22A). 

(The water level in bedrock well 

MW-2D rose by about 0.02 ft 

during the aquifer test.) As previously mentioned, these 

data were not analyzed quantitatively because the complex 

fractured-bedrock/regolith aquifer system does not satisfy 

assumptions of commonly used aquifer-test 

analytical solutions.

 Responses of nearby shallow observation wells measured 

during the 2-day aquifer test indicated a slight measurable 

decline in nearby transition-zone wells and no measurable 

decline in nearby regolith wells or piezometers. Background 

water-level trends in regolith well MW-2S and transition 

zone well MW-2I (cluster MW-2, fig. 5) rose by about 0.05 ft 

during the 2-day aquifer test. The decline in water levels for 

transition zone wells MW-4I, -1I, and -5I was about 0.1 ft 

during the 2-day aquifer test (fig. 22B). (The water level in 

MW-6I (fig. 22B) most likely responded to fluctuations in the 

lake level.) No measurable declines in water levels in regolith 

piezometers WL-1, -2, -3, and -4 and GP-2, -3, -4, -5, -6, -7, 

and -8 were observed. 

Ground-Water Flow

Ground-water flow in hydrogeologic settings of the Piedmont Physiographic Province of North Carolina is assumed to 

flow from high topographic areas (recharge) to lower topoFigure 22. Drawdown response of pumped well (MW-5D) and observation wells measured during 

the January 2003 aquifer test in (A) bedrock wells and (B) transition-zone wells at the Langtree 

Peninsula research station, North Carolina.

0

20

40

60

80

100

120

140

0.15

0.10

0.05

0

-0.05

-0.10

-0.15

0 500 1,000 1,500 2,000 2,500 3,000

DRAWDOWN, IN FEET

TIME, IN MINUTES

A.

B.

EXPLANATION

MW-5D (pumped well)

MW-4D

MW-6D

MW-1D

Barn well

EXPLANATION

MW-4IA

MW-1I

MW-6I

MW-5I

Lake stage

Figure 22. Drawdown response of pumping well (MW-5D) and observation wells 

 measured during the January 2003 aquifer test in (A) bedrock wells and

 (B) transition-zone wells at the Langtree Peninsula research station, North Carolina.
Ground-Water Quality 33

graphic areas (discharge; fig. 5). This system was designated 

a “slope-aquifer system” by LeGrand (2004). Discussions of 

conceptual ground-water flow and influence of topography can 

be found in LeGrand (1967), Heath (1983, 1984), Harned and 

Daniel (1992), and Daniel and Dahlen (2002).

Conceptual models of ground-water flow indicate that 

depth to ground water is greater at topographic highs in 

recharge areas than in topographic lows in ground-water 

discharge areas. Ground-water-level data collected at the 

LPRS generally support this concept. In general, water levels 

are closer to land surface at well clusters MW-3 and MW-6 in 

discharge areas near Lake Norman than in well clusters MW-2 

and MW-1 in recharge areas (figs. 5, 16). 

Shallow Regolith 

The general direction of ground-water flow in the regolith 

underlying the LPRS is consistently toward Lake Norman to 

the north (fig. 23), as determined from data collected from 

5 to 6 wells (well MW-4S later was drilled deeper into the 

transition zone, table 1) and 12 piezometers. Water-level 

altitudes measured in wells tapping the regolith generally 

correspond to topographic setting; the highest water-level 

altitudes during this study were in regolith well MW-2S in the 

higher topographic (recharge) area (table 1), and the lowest 

water-level altitude was near the lake (discharge area; figs. 5, 

23). This is in general agreement with the conceptual groundwater-flow model indicating ground-water discharge to Lake 

Norman. Two ground-water-flow maps of the shallow regolith 

are presented in figure 23—one representing conditions during 

the drought (October 18, 2002; fig. 23A) and one representing 

high water-level conditions (September 23, 2003; fig. 23B). 

Water-level altitudes measured in regolith wells MW-3S and 

MW-6S and piezometers GP-7, GP-8, GP-6, WL-3, and WL-4 

are within 1 ft of the lake stage and each other during October 

2002 (fig. 23A), resulting in a flat hydraulic gradient near Lake 

Norman. During high water-level conditions (September 2003; 

fig. 23B), gradients are slightly steeper toward the lake.

Transition Zone 

Although only 6 to 7 wells were used to evaluate the 

ground-water-flow direction in the transition zone compared 

to 18 wells and piezometers in the shallow regolith (well 

MW-4IB was added after the study was initiated; table 1), 

the general flow direction in the transition zone is similar to 

ground-water-flow directions in the regolith—toward Lake 

Norman to the north (fig. 24). (These flow directions are 

general only, as the locations of all of the wells are along two 

transects (fig. 5).) Ground-water-flow maps of the transition 

zone are presented in figure 24—one representing conditions 

during the drought (October 18, 2002; fig. 24A) and one 

representing high water-level conditions (September 23, 2003; 

fig. 24B). Water-level altitudes measured in wells tapping 

the transition zone generally correspond to topographic 

setting; the highest water-level altitudes were recorded in well 

MW-2I in the higher topographic (recharge) area (fig. 6A), 

and the lowest water-level altitudes in the transition zone 

were recorded near the lake (discharge area) in wells MW-3I 

and MW-6I (figs. 5, 24). This is in general agreement with 

the conceptual ground-water-flow model, which depicts 

ground-water discharge to Lake Norman. Water-level altitudes 

in transition zone wells MW-3I and MW-6I were within a 

few tenths of a foot of each other and the lake (fig. 24), which 

results in a flat hydraulic gradient near Lake Norman. 

Bedrock 

The direction of ground-water flow in the bedrock part 

of the ground-water system at the LPRS, as determined from 

open-borehole water-level data, was similar to the flow in the 

shallow regolith and transition zones—toward Lake Norman 

to the north (fig. 25). (These flow directions are general only, 

as the locations of all of the wells are along a transect from 

south to north at the LPRS.) Water-level altitudes measured in 

wells tapping the bedrock generally correspond to topographic 

setting; the highest water-level altitudes in the bedrock were 

recorded in well MW-2D in the higher topographic (recharge) 

area (fig. 6A), and the lowest water-level altitudes in the 

bedrock were recorded near the lake (discharge area) in 

wells MW-6D, -5D, and -4D (figs. 5, 25). This is in general 

agreement with the conceptual ground-water-flow model, 

which depicts ground-water discharge to Lake Norman. Two 

ground-water-flow maps of the bedrock are presented in 

figure 25—one representing conditions during the drought 

(October 18, 2002; fig. 25A) and one representing high waterlevel conditions (November 7, 2003; fig. 25B). Comparable 

water-level altitudes in wells MW-6D, -5D, and -4D indicate 

that fracture zones tapped by these wells have similar hydraulic heads and are likely interconnected, as confirmed during 

sampling and hydraulic testing.

Interpretation of the open-borehole water levels in 

bedrock wells is complicated because the data represent a 

composite of the hydraulic heads in several fractures tapped 

more than a few hundred feet by the well. The hydraulic head 

within a specific fracture may be different from that measured 

in the entire open borehole. For these reasons, care must be 

taken in the use and interpretation of open-borehole water 

levels in the bedrock wells. 

Ground-Water Quality

Water-quality data from the wells and surface water at 

the LPRS were collected both continuously and at periodic 

sampling events. Continuous monitoring of temperature, pH, 

SC, and DO was conducted at wells MW-2S (in the regolith) 

and MW-2D (in the bedrock). Hourly data were collected from 

August 2002 to July 2003 in well MW-2S, and from August 

2002 to March 2004 in well MW-2D. Periodic samples were 
34 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005 Figure 23. General ground-water-level altitude and flow direction in the shallow regolith at the Langtree Peninsula research station, North Carolina, for (A) October 18, 2002, (drought conditions) and (B) September 23, 2003 (high ground-water-level conditions). <774.57 <774.57

800

810

800

800

790

790

790

780

770

780

780

770

780

770

800

Woods Woods

Lake

Norman

Langtree

Rd.

0 800 FEET 200 400 600

0 200 METERS 50 100 150

Base from digital files ofU.S. Geological SurveyDigital Raster Graph, Lake Norman Quad1:24,000

MW-3S753.26

Lake

Norman

Langtree

Rd.

0 800 FEET 200 400 600

0 200 METERS 50 100 150

800

760

800

810

800

790

790

780

770

780

780

770

Base from digital files ofU.S. Geological SurveyDigital Raster Graph, Lake Norman Quad1:24,000

770

EXPLANATION

810

GP-7753.45

MW-6S753.35

MW-5S

753.37

GP-4761.36

GP-1

GP-6753.65

GP-5

GP-2759.03

GP-3761.95

753.81

WL-2759.03

WL-1757.62

WL-4754.03

MW-1S

MW-2S778.03

MW-3S756.59

GP-7758.45

MW-6S757.20

MW-5S767.25

GP-8757.22

GP-4769.74 GP-1

776.83

GP-6758.20

GP-5761.33

GP-2765.61

Lake-stage altitude 756.52 feet Lake-stage altitude 753.33 feet

GP-3769.67

WL-3758.88

WL-2765.49

WL-1764.54

WL-4759.11

MW-1S

779.07

MW-2S788.82

755

760

765

765

775

770

770

775

780

765

760

758.93

GP-6

B. A.

N

N

790

780

770

Figure 23. General ground-water-level altitude and flow direction in the shallow regolith at the Langtree Peninsula research station,North Carolina, for (A) October 18, 2002, and (B) September 23, 2003.

WL-3

GP-8

760

785

780

<754.81

<766.10

<766.18

Line of equal ground-water-level altitude, in feet above NAVD 88. Contour interval is 5 feet. Dashed where approximateLine of land-surface elevation, in feet above NAVD 88. Contour interval is 10 feetUnfinished roadGround-water-flow directionGround-water-level altitude, in feet above NAVD 88Well and well numberGround-water level was below well- depth altitude, in feet above NAVD 88

800

Woods Woods
Ground-Water Quality 35 Figure 24. Ground-water-level altitude and flow direction in the transition zone at the Langtree Peninsula research station, North Carolina, for (A) October 18, 2002, (drought conditions) and (B) September 23, 2003 (high ground-water-level conditions). Figure 24. Ground-water-level altitude and flow direction in the transition zone at the Langtree Peninsula research station, North Carolina, for

A.

 (A) October 18, 2002, and (B) September 23, 2003 .

N

Lake

Norman

Langtree

Rd.

0 800 FEET 200 400 6000 200 METERS 50 100 150

800

810

800 800

790

790

780

770 780

780

770

Base from digital files ofU.S. Geological SurveyDigital Raster Graph, Lake Norman Quad1:24,000

MW-2788.73

-2I

MW-1I779.18

MW-5I766.81

MW-6IB757.45

MW-3I756.67

Lake756.52

MW-4I774.89

760

765

770

775

780

785

N

Lake

Norman

Langtree

Rd.

0 800 FEET 200 400 600

0 200 METERS 50 100 150

800

810

800 800

790

790

780

770 780

780

770

Base from digital files ofU.S. Geological SurveyDigital Raster Graph, Lake Norman Quad1:24,000

MW-2777.89

-2I

MW-1l770.92

MW-6IB753.39

MW-3l753.26

B.

MW-4IA765.75

775

770

765

755

760

Lake753.33

MW-5I760.02

Woods Woods

Woods Woods

770

EXPLANATION

810

757.45

MW-2l

Line of equal ground-water-level altitude, in feet above NAVD 88. Contour interval is 5 feet. Dashed where approximateAltitude of land surface, in feet above NAVD 88. Contour interval is 10 feetUnfinished roadGround-water-flow directionGround-water-level altitude in feet above NAVD 88Well and well number
36 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005 Figure 25. Ground-water-level altitude and flow direction in the transition zone at the Langtree Peninsula research station, North Carolina, for (A) October 18, 2002, (drought conditions) and (B) November 7, 2003 (high ground-water-level conditions). 770 755 760 765 760 765 770 785 775780 Figure 25. Ground-water-level altitude and flow direction for bedrock at the Langtree Peninsula research station, North Carolina for (A) October 18, 2002 and (B) November 7, 2003. 800 775 EXPLANATION Altitude of land surface, in feet above NAVD 1988. Contour interval is 10 feet. Line of equal ground-water-level altitude, in feet above NAVD 1988. Contour interval is 5 feet. Ground-water monitoring well and number Ground-water-level altitude, in feet above NAVD 1988 Unfinished road 755.55 MW-4D A.

N

Lake

Norman

Langtree

Rd.

0 800 FEET 200 400 6000 200 METERS 50 100 150

800

810

800

800

790

790

780

770

780

780

770

Base from digital files ofU.S. Geological SurveyDigital Raster Graph, Lake Norman Quad1:24,000

MW-2775.33

-2D

MW-1D763.78

MW-5D755.08

MW-6D755.10

Lake753.33

MW-4D755.55

N

Lake

Norman

Langtree

Rd.

0 800 FEET 200 400 6000 200 METERS 50 100 150

800

810

800

800

790

790

780

770

780

780

770

Base from digital files ofU.S. Geological SurveyDigital Raster Graph, Lake Norman Quad1:24,000

MW-2785.20

-2D

MW-1D771.71

MW-6D759.36

B.

MW-4D760.54

Lake756.07

MW-5D759.31

Ground-water flow direction

Woods Woods

Woods

Woods
Ground-Water Quality 37

collected from the cluster wells and Lake Norman during 

two sampling events in August 2002 and March 2003 and 

from one well in June 2004. Water-quality analyses included 

selected major ions, nutrients, metals, radiochemicals, and 

physical properties (table 4). Methods and instrumentation 

used for both the continuous monitoring and periodic sampling 

are described in the “Methods” section of this report and in the 

SOP for this study (North Carolina Department of Environment and Natural Resources, Division of Water Quality, and 

U.S. Geological Survey, Water Resources Division, 2002). 

Continuous water-quality monitoring data and periodic 

water-quality sampling data are published in USGS water-data 

reports for water years 2002, 2003, and 2004 (Howe and 

others, 2003, 2004, 2005). 

Continuous Monitoring Data 

An important use of continuous ground-water-quality 

monitoring data is to evaluate the chemical response of the 

aquifer system during climatic variations (seasonal trends) 

in the hydrologic system and short-term rainfall events. 

Seasonal trends are a function of recharge, which typically 

is greatest during the winter and early spring months, and 

evapotranspiration, which is greatest during the late spring and 

summer months. Chemistry of the aquifer may change as a 

result of the infiltration of rainfall and potential interaction of 

components of the ground water.

Seasonal Trends

Continuously monitored field properties recorded in 

regolith well MW-2S (fig. 26) and bedrock well MW-2D 

(fig. 27) changed slowly (seasonally) throughout the monitoring period. This was not unexpected, as a similar response was 

observed in continuously recorded ground-water-level data 

(fig. 17).

General trends with well depth in the ground-water 

system are evident from a comparison of shallow ground water 

in regolith well MW-2S (fig. 26) and deep bedrock ground 

water in well MW-2D (fig. 27). In general, pH increases, 

DO decreases, and temperature becomes stable at increasing 

depths in the ground-water system. These findings are similar 

to those reported at the Lake Wheeler Road research station 

(Chapman and others, 2005). These observations most likely 

are the result of a lesser degree of interaction with rainfall at 

depth. In the bedrock, ground water has a longer residence 

time, and the pH increases from dissolution of the alkaline 

minerals. Shallow ground water in the regolith receives larger 

amounts of acidic (lower pH) rainfall than deep ground water. 

Overall, the shallow ground water in regolith well MW-2S 

had a larger seasonal fluctuation in water-quality properties 

(fig. 26) than ground water in the deep bedrock well MW-2D 

(fig. 27). The observed seasonal temperature fluctuation 

in regolith well MW-2S was substantially greater than the 

temperature range in the deeper bedrock well MW-2D. 

Temperature

The magnitude of seasonal ground-water temperature 

fluctuations was less with increasing depth at the LPRS. Temperatures in shallow regolith well MW-2S fluctuated about 0.6 

degree Celsius (°C) during a year of monitoring (fig. 26), but 

water temperatures in bedrock well MW-2D fluctuated only 

0.1°C during more than 20 months of monitoring (fig. 27). 

Table 4. Analyses conducted on water-quality samples collected during periodic sampling events at the 

Langtree Peninsula research station, North Carolina.

[NC, not collected]

Sampling date

Major 

ionsa, b

(dissolved)

Nutrientsa, c

(dissolved)

Metalsa, d

(dissolved)

Radon 222 

(gas)a

(total)

Gross alphae

(total)

August 26–28; September 3, 2002f X X NC X X

March 3–5, 2003 X X X X X

June 15–17, 2004g X X X NC NC

a

 Analyzed by the U.S. Geological Survey National Water Quality Laboratory, Denver, Colorado. 

b

 Major ions analyzed were bromide, calcium, chloride, fluoride, magnesium, potassium, silica (as SiO2), sodium, and sulfate. 

c

 Nutrients analyzed were ammonia, nitrogen as nitrate, nitrogen as nitrite, nitrate plus nitrite, organic nitrogen, orthophosphorus, and orthophosphate.

d

 Metals analyzed were aluminum, antimony, arsenic, barium, beryllium, boron, cadmium, chromium, cobalt, copper, iron, 

lead, manganese, mercury, molybdenum, nickel, selenium, silver, uranium, and zinc.

e

 Analyzed by STL Laboratories, Richland, Washington (contracted by the U.S. Geological Survey National Water 

Quality Laboratory).

f

 Only Lake Norman samples were collected on September 3, 2002.

g

 Only well MW-2D was sampled in June 2004.
38 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Figure 26. Hourly record of (A) ground-water levels, (B) temperature, (C) pH, (D) specific conductance, and (E) dissolved oxygen in well 

MW-2S in the shallow regolith at the Langtree Peninsula research station, North Carolina; and (F) monthly rainfall data from Norman Shores 

rain gage, Lake Norman, North Carolina.

10

8

6

4

DISSOLVED OXYGEN, IN

MILLIGRAMS PER LITER

120

100

80

60

40

20

0

17.5

17.0

16.5

16.0

15.5

WATER TEMPERATURE,

IN DEGREES CELSIUS

10

15

20

25

GROUND-WATER LEVELS,

30

IN FEET BELOW NAVD 88

8

7

6

5

pH

B.

A.

C.

D.

E.

Figure 26. Hourly record of (A) ground-water levels, (B) temperature, (C) pH, (D) specific conductance, and (E) dissolved oxygen

 in well MW-2S in the shallow regolith at the Langtree Peninsula research station, North Carolina; and (F) monthly rainfall data from

 Norman Shores rain gage, Lake Norman, North Carolina.

SPECIFIC CONDUCTANCE,

IN MICROSIEMENS PER

CENTIMETER AT

25 DEGREES CELSIUS

2002 2003

AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER JANUARY

WATER YEAR

FEBRUARY MARCH APRIL MAY JUNE JULY

0

2

4

6

8

10

12

MONTHLY RAINFALL,  IN INCHES

F.
Ground-Water Quality 39

Figure 27. Hourly record of (A) ground-water levels, (B) temperature, (C) pH, (D) specific conductance, and (E) dissolved oxygen in well 

MW-2D in the bedrock at the Langtree Peninsula research station, North Carolina; and (F) monthly rainfall data from Norman Shores rain gage, 

Lake Norman, North Carolina.

2002 2003

WATER YEAR

2004

B.

A.

C.

D.

E.

Figure 27. Hourly record of (A) ground-water levels, (B) temperature, (C) pH, (D) specific conductance, and (E) dissolved oxygen

 in well MW-2D in the bedrock at the Langtree Peninsula research station, North Carolina; and (F) monthly rainfall data from

 Norman Shores rain gage, Lake Norman, North Carolina.

AUG. SEPT. OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC. JAN. FEB. MAR.

F.

DISSOLVED OXYGEN,

IN MILLIGRAMS 

PER LITER

WATER TEMPERATURE,

IN DEGREES CELSIUS

10

15

20

25

30

pH

SPECIFIC CONDUCTANCE,

IN MICROSIEMENS PER

CENTIMETER AT

25 DEGREES CELSIUS

12

10

8

6

4

2

0

MONTHLY RAINFALL, IN INCHES GROUND-WATER LEVELS, IN FEET BELOW NAVD 88

17.5

17.0

16.5

16.0

15.5

10

8

6

4

120

100

80

60

40

20

0

8

7

6

5
40 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

A seasonal pattern was observed 

in the shallow regolith ground-water 

temperature recorded in well MW-2S; 

however, the pattern was substantially 

delayed (about 5 months) with 

respect to air temperature (fig. 28). 

The highest shallow ground-water 

temperatures were recorded during 

February–March 2003 and the lowest 

during August–September 2002 and 

June–July 2003. By contrast, as is 

typical of air temperature, the highest 

temperatures were recorded during 

summer months (July and August) and 

the lowest temperatures were recorded 

during late January and early February 2003 (fig. 28). The delay of the 

air-temperature “signal” may indicate 

slow ground-water recharge and is 

similar to the responses recorded at the 

Lake Wheeler Road research station 

(Chapman and others, 2005).

pH

Ground water in the shallow regolith and bedrock has a 

slightly acidic to acidic pH and generally increases with depth 

(figs. 26, 27). The lower pH in shallow zones likely is the 

result of infiltration of acidic precipitation and the presence of 

carbonic acid (produced as carbon dioxide from the decay of 

organic matter (Drever, 1988)). The increase in pH at depth in 

the bedrock indicates increased residence time for the dissolution of minerals. Values of pH in the regolith ranged from 

about 5.6 to 6.4, whereas values in the bedrock ground water 

ranged from about 6.4 to 7.5.

Specific Conductance

As with pH, specific conductance (SC) slightly increased 

when shallow ground water in the regolith was compared to 

ground water in the deeper bedrock (figs. 26, 27). Specific 

conductance for well MW-2S ranged from about 31 to 

88 microsiemens per centimeter at 25 degrees Celsius 

(μS/cm) during the period of study (fig. 26), whereas SC for 

well MW-2D ranged from about 89 to 97 (fig. 27). The values 

of SC for well MW-2D are somewhat low in relation to SC 

values for most areas of the Piedmont. Initially, casing leakage 

was thought to be a potential means of connection with the 

overlying regolith. However, heat-pulse flowmeter logging of 

well MW-2D (app. 2) did not measure any downward flow 

near the bottom of the casing, which indicates the well was 

sealed properly. Daniel and Dahlen (2002) reported a mean SC 

value of about 387 μS/cm for the Piedmont, which is considerably higher than the SC values recorded in bedrock well 

MW-2D. The influence of nearby pumping wells (fig. 19) and 

the naturally downward vertical gradient (figs. 16, 17) may 

induce interaction with the more diluted overlying regolith and 

lower the overall SC values in this well.

Dissolved Oxygen

Dissolved-oxygen (DO) concentrations in wells MW-2S 

and MW-2D decreased slightly with depth. Dissolved-oxygen 

concentrations in the shallow regolith well (MW-2S) ranged 

from about 5.7 to 7.4 milligrams per liter (mg/L; fig. 26), 

and DO concentrations in the deeper bedrock well (MW-2D) 

ranged from about 4.8 to 5.9 mg/L (fig. 27). The higher DO 

concentrations in the regolith well indicate a more direct interaction with precipitation. Dissolved-oxygen concentrations in 

the bedrock well were higher than expected. Casing leakage 

was again suspected; however, as stated above, no leakage 

was measured using heat-pulse flowmeter logging near the 

bottom of the casing. These DO values are comparable to the 

mean DO values reported by Daniel and Dahlen (2002) for the 

Piedmont region in a report that summarized data collected 

as part of the APRASA study (Briel, 1997) in North Carolina 

that focused primarily on domestic wells that are pumped. The 

elevated DO value in the bedrock well at the LPRS may be 

influenced by nearby pumping wells (fig. 19) and the naturally 

downward vertical gradient in this area, as observed in the 

water-level data recorded in this well (figs. 16, 17). 

Response to Recharge 

Continuous water-quality monitoring data provide 

insights into the processes and interactions of components 

of the ground-water system during short-term rainfall events 

or extended periods of increased precipitation. During water 

years 2001 and 2002 (drought years), water levels in MW-2 

Figure 28. Ground-water temperature recorded in shallow regolith well MW-2S in relation 

to air temperature recorded at the North Carolina State Climate Weather Station (2NNE) 

in Statesville.

Air temperature

Ground-water temperature

Figure 28. Ground-water temperature recorded in shallow regolith well MW-2S in relation to air

 temperature recorded at the North Carolina State Climate Weather Station (2NNE) in Statesville.

90

80

70

60

50

40

30

20

10

0

AUG. SEPT.

2002 2003

OCT. NOV. DEC. JAN. FEB. MAR. APR. MAY JUNE JULY

AIR TEMPERATURE, DEGREES FAHRENHEIT

62.5

62.0

61.5

61.0

60.5

60.0

GROUND-WATER TEMPERATURE, IN DEGREES CELSIUS
Ground-Water Quality 41

wells did not respond to short-term rainfall events or longer 

periods of increased recharge (fig. 17; see discussion in the 

“Ground-Water Levels” section of this report). However, 

following above-normal rainfall during water year 2003, the 

ground-water level in well MW-2S rose more than 1 ft over 

about a 2-week period in June and July 2003 (fig. 29). Waterquality changes also were observed in regolith well MW-2S 

within 2–3 weeks after the ground-water-level rise began and 

occurred for a similar duration as the water level rose. During 

this period, DO concentrations increased in the shallow 

regolith ground water in well MW-2S (+1.7 mg/L, fig. 29A), 

while pH and SC decreased (-0.5 and -39 μS/cm, respectively, 

fig. 29B, C). Temperature continued to respond seasonally 

and did not markedly fluctuate during this recharge period. 

All of these water-quality property changes are indicative of 

rainfall infiltration over a period of a few to several weeks and 

likely reflect saturation from above-normal rainfall during 

March through July 2003 and a resulting shorter-term flux of 

water-quality interactions between rainfall and shallow ground 

water in the regolith. (Rainfall generally is more acidic, has 

higher DO concentrations, and is more dilute [lower specific 

conductance] than ground water.) Water-quality properties 

recorded in bedrock well MW-2D did not fluctuate in response 

to this recharge period.

Results from Periodic Water-Quality Sampling 

Water-quality samples were collected periodically from 

the LPRS wells to characterize ground-water chemistry in the 

quartz diorite rock type. Water-quality samples were collected 

from the cluster wells and the lake during three sampling 

events (table 4). Samples were analyzed for major ions and 

nutrients for two sampling events; additionally, metals, radon 

222 (gas) concentrations, and gross alpha activity were 

analyzed in samples collected during two events. All of the 

cluster wells were sampled in August 2002 and March 2003, 

and one well was sampled in June 2004. Two samples, “top” 

(about 1 ft below the water surface) and “bottom” (about 1 ft 

above the lake bottom), were collected from Lake Norman 

during each sampling event. These analytical results are 

published in USGS North Carolina annual water-data reports 

for the respective water years (Howe and others, 2003, 

2004, 2005). 

One of the objectives of this study was to compare 

ground-water-quality data from each water-bearing zone of 

the ground-water system—the regolith, transition zone, and 

bedrock. Field properties measured during periodic sampling 

events provide a means of comparing geochemical conditions. 

General trends in field water-quality properties during periodic 

sampling events (fig. 30; Howe and others, 2003, 2004, 2005) 

were similar to trends in the continuous water-quality data 

(figs. 26, 27) in that pH and SC increased and DO decreased 

with depth in the ground-water system.

Standard graphical tools used for the geochemical 

comparison of ground-water-quality data are Piper trilinear 

diagrams and Stiff diagrams. The Piper diagram is a multipletrilinear diagram that segregates analytical data with respect 

to dissolved major cations and anions in ground water (Piper, 

1953). The Stiff diagram is used to display dominant cations 

and anions (Stiff, 1951). Figures 31 and 32 display Piper and 

Stiff diagrams, respectively, for each zone of the ground-water 

system—regolith, transition zone, and bedrock. Comparisons 

of the range of major ion concentrations in each of the three 

zones are shown in figures 33 and 34. The bedrock has the 

highest median concentrations of calcium, sodium, and 

bicarbonate, and concentrations generally increased with 

depth in the ground-water system. Samples collected from 

the transition zone had the highest median concentrations of 

magnesium, while samples collected from Lake Norman had a 

higher overall concentration of chloride.

Most of the ground-water samples collected at the LPRS 

are calcium-bicarbonate water types (figs. 31, 32). Samples 

from all three zones of the ground-water system have similar 

geochemistry at the LPRS. Regolith well MW-3S, located 

near Lake Norman, was somewhat different in that sodium 

was the dominant cation. Similarly, the sample collected from 

the top of the water column in Lake Norman was a sodiumchloride type, potentially indicating the influence of local 

septic systems. The Davidson College Lake Campus includes 

restrooms and a nearby septic field within 100 ft of the lake 

and well cluster MW-3. No distinction could be made in 

ground-water samples collected from recharge areas compared 

with ground-water samples from discharge areas based on 

these major ion analyses. (Some well samples [bedrock wells 

MW-4D, -5D, and -6D] are not included in this report because 

they potentially were affected by well-construction practices 

and grout contamination, possibly indicated by a calciumsulfate water type and high SC concentrations.)

Ground-Water-Quality Changes with Depth

A comparison of water chemistry with depth (figs. 30, 

32–34) indicates an increase in total solutes, such as calcium 

and bicarbonate. Along with an increase in pH with depth 

(fig. 30), this indicates an increase in ground-water residence 

time with depth, which allows greater dissolution of minerals in the bedrock. Also, the lower DO concentrations in 

ground water in the bedrock indicate reduced recharge from 

precipitation and partial disconnection of the deeper part of the 

ground-water system (bedrock) with the overlying regolith and 

transition zone, which receives and stores most of 

the recharge. 

Shallow Regolith Ground Water and Surface Water

As previously discussed, samples from three shallow 

regolith wells had different geochemical characteristics. Water 

from well MW-2S (recharge area, fig. 6A) was a calcium/

magnesium-bicarbonate type water (figs. 31, 32). The water 
42 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Figure 29. Response of (A) dissolved oxygen, (B) pH, and (C) specific conductance in regolith well 

MW-2S to rainfall in June and July 2003 at the Langtree Peninsula research station, North Carolina.

5.4

5.5

5.6

5.7

5.8

5.9

6.1

6.0

6.2

6.3

HOURLY pH, IN STANDARD UNITS

WATER LEVEL, IN FEET BELOW LAND SURFACE WATER LEVEL, IN FEET BELOW LAND SURFACE WATER LEVEL, IN FEET BELOW LAND SURFACE

RAINFALL, IN INCHES RAINFALL, IN INCHES RAINFALL, IN INCHES

1

0

2

3

4

5

6

7

HOURLY DISSOLVED OXYGEN, IN MILLIGRAMS PER LITER

A.

B.

C.

10

0

20

30

40

50

60

70

HOURLY SPECIFIC CONDUCTANCE, IN MICROSIEMENS

PER CENTIMETER

Figure 29. Response of (A) dissolved oxygen, (B) pH, and (C) specific conductance

 in regolith well MW-2S to rainfall in June and July 2003 at the Langtree Peninsula

 research station, North Carolina.

12.5

13.0

13.5

14.0

14.5

15.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

12.5

13.0

13.5

14.0

14.5

15.0

12.5

13.0

13.5

14.0

14.5

15.0

Water level

Dissolved oxygen

Rainfall

Water level

pH

Rainfall

Water level

Specific conductance

Rainfall

1 3 5 7 9 11 13 15 17

JUNE JULY

2003

19 21 23 25 27 29 1 3 5 7 9 11 13 15 17 19 21
Ground-Water Quality 43

Figure 30. Box plots showing range, median, and quartile statistical 

values for (A) pH, (B) specific conductance, and (C) dissolved oxygen in 

the wells and Lake Norman recorded during periodic sampling events at 

the Langtree Peninsula research station, North Carolina.

7.5

7.0

6.5

6.0

5.5

5.0

300

250

200

150

100

50

0

11

9

7

5

3

1

Transition Bedrock

zone

Lake Regolith

Norman

pH, IN STANDARD UNITS

SPECIFIC CONDUCTANCE, IN MICROSIEMENS

PER CENTIMETER DISSOLVED OXYGEN, IN MILLIGRAMS PER LITER

Upper detached

EXPLANATION

Upper adjacent

Lower adjacent

Sample count

Bedrock

Transition zone

Regolith

Lake Norman

75th percentile

25th percentile

Median

N=3

N=11

N=6

N=2

Figure 30. Box plots showing range, median, and quartile statistical values for (A) pH, (B) specific conductance, and (C) 

dissolved oxygen in the wells and Lake Norman recorded during periodic sampling events at the Langtree Peninsula 

research station, North Carolina.

A.

B.

C.
44 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Figure 31. Piper diagrams showing the distribution of major ions in periodic ground-water and surfacewater samples from the (A) regolith and transition-zone wells and Lake Norman, and (B) open-borehole 

bedrock wells at the Langtree Peninsula research station, North Carolina.

MW-1D 

MW-2D 

EXPLANATION

MW-2S

MW-3S

MW-6S

EXPLANATION 80 

100 

60 

40 

20 

0 

80 

60 

40 

20 

0 

SULFATE PLUS CHLORIDE PLUS NITRATE 

80 

100 

60 

40 

20 

20 

0 

40 

60 

80 

0 100 100 

60 40 20 

CALCIUM 

CATIONS

100 80 0 

20 

40 

60 

80 

100 

20 

40 

60 

80 

0 

20 

40 

60 

80 

MAGNESIUM 

SODIUM PLUS POTASSIUM 

40 60 80 

CHLORIDE PLUS NITRATE 

ANIONS 

0 20 100 

60 40 20 

CALCIUM 

CATIONS

100 80 

B.

A.

0 40 60 80 

CHLORIDE PLUS NITRATE 

ANIONS 

0 20 100 

CARBONATE PLUS BICARBONATE 

0 0 

20 

0 

40 

60 

80 

100 100 

20 

40 

60 

80 

100 

20 

40 

60 

80 

0 

20 

40 

60 

80 

SODIUM PLUS POTASSIUM 

CARBONATE PLUS BICARBONATE 

80 

100 

60 

40 

20 

0 

SULFATE 

80 

100 

60 

40 

20 

0 

MAGNESIUM 

80 

100 

60 

40 

20 

0 

SULFATE 

CALCIUM PLUS MAGNESIUM 

80 

100 

60 

40 

20 

80 

60 

40 

20 

SULFATE PLUS CHLORIDE PLUS NITRATE 

CALCIUM PLUS MAGNESIUM 

Figure 31. Piper diagrams showing the distribution of major ions in periodic ground-water and surface-

 water samples from the (A) regolith and transition-zone wells and the lake site, and (B) open-borehole

 bedrock wells at the Langtree Peninsula research station, North Carolina.

Lake Norman, 12-foot depth (bottom sample)

Lake Norman, 2-foot depth (top sample)

MW-1I

MW-3I

MW-4I

MW-5I

MW-6IB

3/5/03 

3/5/03 

3/5/03 

3/5/03 

3/5/03 

3/3/03 

3/3/03 

3/4/03 

8/26/02 

8/26/02 

8/27/02 

8/28/02 8/28/02 

8/24/02 

8/28/02 

3/4/03 

6/15/04 

3/04/03 
Ground-Water Quality 45

Figure 32. Stiff diagrams showing major ion milliequivalents in water samples collected from (A) the regolith wells and Lake 

Norman, (B) the transition-zone wells, and (C) the open-borehole bedrock wells at the Langtree Peninsula research station, 

North Carolina, March 2003.

2 1 1 2

A.

2 1 1 2

B.

5 2.5 2.5 5

C.

Sodium

Lake Norman

2-foot depth

(top sample)

Lake Norman

12-foot depth

(bottom sample)

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Sodium

MW-1I

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Sodium

MW-1D

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Sodium

MW-2D

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Sodium

MW-3I

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Sodium

MW-4IA

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Sodium

MW-5I

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Sodium

MW-6IB

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Ammonia,

as Nitrogen

Sodium

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Sodium

MW-2S

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Sodium

MW-3S

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Sodium

MW-6S

Calcium

Chloride

Bicarbonate

Magnesium Sulfate

Figure 32. Stiff diagrams showing major ion milliequivalents in water samples collected from (A) the regolith wells

and Lake Norman, (B) the transition-zone wells, and (C) the open-borehole bedrock wells at the Langtree Peninsula

research station, North Carolina, March 2003.

Nitrite plus Nitrate 

Nitrite plus Nitrate 

Nitrite plus Nitrate 

Nitrite plus Nitrate Nitrite plus Nitrate 

Nitrite plus Nitrate 

Nitrite plus Nitrate 

Nitrite plus Nitrate 

Nitrite plus Nitrate 

Nitrite plus Nitrate 

Nitrite plus Nitrate 

MILLIEQUIVALENTS PER LITER MILLIEQUIVALENTS PER LITER MILLIEQUIVALENTS PER LITER

Nitrite plus Nitrate 
46 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Figure 33. Box plots showing range, median, 

and quartile statistical values for (A) calcium, 

(B) magnesium, and (C) sodium in the wells and 

Lake Norman recorded during periodic sampling 

events at the Langtree Peninsula research station, 

North Carolina.

Figure 34. Box plots showing range, median, 

and quartile statistical values for (A) bicarbonate, 

(B) chloride, and (C) sulfate in the wells and 

Lake Norman recorded during periodic sampling 

events at the Langtree Peninsula research 

station, North Carolina.

7.5

7.0

6.5

6.0

5.5

5.0

4

3

2

1

0

10

8

6

4

2

0

Transition Bedrock

zone

Lake Regolith

Norman

CALCIUM, IN MILLIGRAMS PER LITER MAGNESIUM, IN MILLIGRAMS PER LITER SODIUM, IN MILLIGRAMS PER LITER

Upper detached

EXPLANATION

Upper adjacent

Lower adjacent

Sample count

Bedrock

Transition zone

Regolith

Lake Norman

75th percentile

25th percentile

Median

N=3

N=11

N=6

N=2

Figure 33. Box plots showing range, median, and quartile statistical values for (A) calcium, (B) magnesium, and 

 (C) sodium in the wells and Lake Norman recorded during periodic sampling events at the Langtree Peninsula

 research station, North Carolina.

A.

B.

C.

90

80

70

60

50

40

30

20

10

0

16

14

12

10

8

6

4

2

0

25

20

15

10

5

0

Transition Bedrock

zone

Lake Regolith

Norman

BICARBONATE, IN MILLIGRAMS PER LITER CHLORIDE, IN MILLIGRAMS PER LITER SULFATE, IN MILLIGRAMS PER LITER

Figure 34. Box plots showing range, median, and quartile statistical values for (A) bicarbonate, (B) chl

 (C) sulfate in the wells and Lake Norman recorded during periodic sampling events

 at the Langtree Peninsula research station, North Carolina.

A.

B.

C.
Ground-Water Quality 47

types in wells MW-3S and MW-6S, both located in discharge 

areas near the lake (fig. 5), were sodium-bicarbonate and 

calcium/magnesium-bicarbonate, respectively (figs. 31, 32). 

Water samples collected from regolith well MW-3S had a 

dominant sodium cation, which was similar to the top samples 

collected from Lake Norman and likely indicates interaction 

of shallow ground water with the lake and potential effects 

of the nearby septic field. Restrooms used at the Davidson 

College Lake Campus are located within a few hundred feet of 

well MW-3S. Although well MW-6S also is located near the 

lake, samples from this well contained similar concentrations 

of calcium and magnesium. There was no apparent trend in 

ground-water-sample chemistry from recharge to discharge 

areas in the regolith part of the ground-water system. (Two 

shallow regolith wells, MW-1S and -5S, were dry at the time 

of sampling.)

Two Lake Norman samples differ in water type 

(fig. 32A). The top sample is a sodium-chloride type water, 

and the bottom sample is a sodium/magnesium-bicarbonate 

type water. The top sample water type seems to be affected 

by surface runoff and possibly septic discharge, as indicated 

by low bicarbonate and elevated sodium concentrations. The 

bottom sample water type is influenced more by ground water, 

as indicated by the increase in bicarbonate.

Transition-Zone Ground Water

Ground-water-quality samples from all five transitionzone wells at the LPRS had similar water types—calcium 

bicarbonate and calcium-magnesium bicarbonate 

(figs. 31, 32). Ground water from this zone generally was 

similar to that from the shallow regolith well (MW-2S) 

and the two bedrock wells (MW-1D and MW-2D) sampled. 

There was no apparent trend in ground-water chemistry 

from recharge to discharge areas in the transition zone. 

 Bedrock Ground Water

Water from two of the open-borehole bedrock wells was 

generally calcium-bicarbonate type (figs. 31, 32). The bedrock 

ground-water samples were collected near the most transmissive fracture zone in each well. A comparison of the shallow 

(regolith and transition zone) and deeper (bedrock) parts of 

the ground-water system indicates increased pH and lower DO 

concentrations with depth (fig. 30). Analytical results indicate 

that samples from the bedrock wells had higher concentrations 

of fluoride, calcium, sulfate, molybdenum, uranium, radon, 

and arsenic than samples from the shallower wells (Howe and 

others, 2002, 2003). Samples from bedrock wells also had 

high pH, which supports the concept of increased residence 

time for mineral dissolution within the quartz diorite.

Radiochemicals and Radon Gas

Radiochemicals and radon gas are of interest in igneous 

and metamorphic rocks because natural concentrations can 

be elevated. The concentration of radon gas in ground water 

has been the subject of much consideration by the U.S. 

Environmental Protection Agency (USEPA). The proposed 

Federal standards for public drinking-water supplies provide 

two options for the maximum allowable level of radon in 

community water systems (CWSs)—an untreated maximum 

contaminant level (MCL) of 300 picocuries per liter (piC/L) 

and a proposed alternative MCL (AMCL) of 4,000 piC/L 

(U.S. Environmental Protection Agency, 2000b). The AMCL 

would apply to States and CWSs for which a multimedia 

mitigation program has been developed to address radon 

concentrations in indoor air. Radon 222 samples from all components of the LPRS ground-water system (regolith, transition 

zone, and bedrock) in the mafic quartz diorite rock type were 

low compared with radon concentrations in the more granitic 

(felsic) rock types, such as at Lake Wheeler Road research 

station (Chapman and others, 2005). Samples collected 

at the Lake Wheeler Road research station had radon 222 

concentrations ranging from about 400 piC/L in surface water 

to more than 12,000 piC/L in the transition zone (Howe and 

others, 2003, 2004). By contrast, radon 222 concentrations in 

LPRS wells ranged from about 20 to 500 piC/L. Gross alpha 

concentrations did not exceed the recommended drinkingwater standard of 15 piC/L (U.S. Environmental Protection 

Agency, 2000a; North Carolina Department of Environment 

and Natural Resources, Division of Water Quality, 2002) and 

ranged from 0.3 to 1.6 piC/L (Howe and others, 2003, 2004). 

Nutrients

Nitrate concentrations generally were low in groundwater samples collected at the LPRS and ranged from about 

0.07 to 1.6 mg/L (Howe and others, 2003, 2004). Three 

transition-zone wells—MW-3I, 4I, and 5I—had nitrate 

concentrations greater than 1 mg/L. These slightly elevated 

concentrations may be related to the nearby Davidson College 

Lake Campus restroom septic system or to previous agricultural activities at the site. 

Comparisons with Regional Ground-WaterQuality Data

To gain a perspective on how water-quality data from 

the LPRS compare with regional water quality, a summary 

of analytical data for bedrock wells tapping the metaigneous, 

intermediate (MII) regional hydrogeologic unit (Daniel and 
48 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

Payne, 1990) was compiled from the arsenic database at the 

North Carolina Department of Environment and Natural 

Resources, Division of Water Quality, Mooresville Regional 

Office (Chuck Pippin, North Carolina Division of Water 

Quality, written commun., 2005). From the analyses of 

326 water-quality samples collected from the MII unit, mean 

concentrations were 27 mg/L for calcium, 5 mg/L for chloride, 

0.06 mg/L for fluoride, and 0.4 mg/L for iron. Laboratory 

results of pH indicated an average of about 7.2, and mean 

alkalinity was about 70 mg/L. Bedrock samples collected at 

the LPRS had mean field readings and ion concentrations of 

13 mg/L for calcium, 1.4 mg/L for chloride, <0.1 mg/L for 

fluoride, <10 micrograms per liter (μg/L) for iron, 7.2 units for 

pH, and 56 mg/L for alkalinity. 

Comparison of Ground-Water Chemistry 

to Rock Chemistry

Mean whole-rock analyses from quartz diorite core 

samples (three samples) were compared to mean dissolved 

ions and trace metals in ground-water samples collected from 

bedrock wells MW-1D and MW-2D (four samples total; 

table 5). The dominant major ion species from selected core 

samples (means) were silica (54 percent), followed 

by aluminum (18 percent), iron (9.3 percent), calcium 

(8.7 percent), magnesium (4.6 percent), and sodium (3.1 percent; table 5). Compared to the geochemical characteristics 

of the bedrock ground-water samples collected from well 

MW-1D (one sample) and MW-2D (3 samples), the major 

dissolved ions in ground water are silica (36 mg/L), calcium 

(13 mg/L), and sodium (5.2 mg/L). Substantial concentrations 

of the following trace metals also were detected in the bedrock 

ground-water samples at the LPRS, including molybdenum 

(8.5 g/L), aluminum (7.6 g/L), and barium (4.8 g/L).

Summary

The Langtree Peninsula research station (LPRS), located 

on the Davidson College Lake Campus on Lake Norman in 

Iredell County, North Carolina, is representative of the metaigneous, intermediate hydrogeologic unit within the Charlotte 

Table 5. Analytical results of arithmetic mean whole-rock core composition from three 

quartz diorite bedrock cores and arithmetic mean dissolved major ion concentrations 

in five bedrock ground-water samples collected from wells MW-1D and MW-2D at the 

Langtree Peninsula research station, North Carolina. 

[MW, monitoring well; %, percentage of sample weight; ppm, parts per million; mg/L, milligrams per 

liter; g/L, micrograms per liter; <, less than; na, not analyzed]

Composition of whole-rock quartz 

diorite core samplesa

Major ion concentrations in ground water 

(bedrock wells MW-1D and MW-2D)

Species or 

metal

Weight , 

in percent (%) or 

concentration (ppm)

Dissolved ion Concentration 

(mg/L or μg/L)

Silica 53.9 % Silica 36 mg/L as SiO2

Aluminum 17.7 % Aluminum 7.6 μg/L as Al

Calcium 8.7 % Calcium 13 mg/L as Ca

Magnesium 4.6 % Magnesium 2.6 mg/L as Mg

Sodium 3.1 % Sodium 5.2 mg/L as Na

Potassium 0.8 % Potassium 2.0 mg/L as K

Iron 9.3 % Iron < 10 μg/L as Fe

Manganese 0.2 % Manganese 0.5 μg/L as Mn

Chromium na Chromium 0.9 μg/L as Cr

Silver < 1 ppm Silver < 0.2 μg/L as Ag

Barium 155 ppm Barium 4.8 μg/L as Ba

Cobalt na Cobalt 0.06 μg/L as Co

Copper 61 ppm Copper 0.5 μg/L as Cu

Molybdenum 1.3 ppm Molybdenum 8.5 μg/L as Mo

Nickel 21 ppm Nickel 0.6 μg/L as Ni

Antimony < 2 ppm Antimony 1.3 μg/L as Sn

Uranium 3.5 ppm Uranium 1.8 μg/L as U

Zinc 76 ppm Zinc 1.4 μg/L as Zn

a J. Wright Horton, Jr., U.S. Geological Survey, Reston, Virginia, written commun., 2001.
References 49

lithotectonic belt/Charlotte terrane in the Piedmont region. 

This research station was established as part of the cooperative 

Piedmont and Mountains Resource Evaluation Program 

between the North Carolina Division of Water Quality and the 

U.S. Geological Survey. The dominant rock type at the LPRS 

is a mafic quartz diorite having steeply dipping foliation (60°) 

and variable depth to consolidated bedrock from about 24 to 

76 ft. Thickness of the delineated transition zone was highly 

variable, from about 1 to 20 ft. 

Primary and secondary foliations are present in the 

quartz diorite at the LPRS, both having a mean strike of about 

N. 12°E. and a mean dip of about 60° in opposite directions 

to the southeast (primary) and the northwest (secondary). The 

quartz diorite rock type also is cut by granitic dikes ranging 

in thickness from about 2 to 50 ft, with a mean strike of 

N. 20°W. and a mean dip angle of 66° to the southwest.

Bedrock well yields ranged from about 3 to 50 gal/min. 

The highest yield of 50 gal/min is from shallow transitionzone fractures at a depth of 59 ft. Delineated bedrock fractures 

dominantly are low angle (likely stress relief) and are open to 

partially open at depths up to 479 ft. Open (primary) fracture 

sets measured in the bedrock wells have orientations of 

N. 49–70° E. dipping 10–24° SE., N. 17 ° E. dipping 10° SE., 

and N. 20–21° W. dipping 5–28° NE.-SW. 

Ground-water flow at the LPRS generally supports the 

historical conceptual models developed in previous studies. 

General ground-water flow was toward a surface-water 

drainage—Lake Norman. Additionally, the vertical gradient 

directions at well cluster MW-6 supported earlier concepts 

of upward movement of ground-water in discharge areas. In 

the recharge areas near clusters MW-2 and MW-1, vertical 

gradients were downward, as expected from the conceptual 

model. Vertical gradients at the mid-slope clusters MW-4 

and MW-5 also were downward. Flat hydraulic gradients in 

the regolith zone of the ground-water system were noted at 

distances within 300 ft of the lake shore, indicating potential 

interactions between ground water and surface water in 

these areas. 

The ground-water quality data (both continuous monitoring and periodic sampling) collected at the LPRS aid in 

understanding how various components of the ground-water 

system interact. Overall geochemistry was similar among 

major ions in ground water from the regolith, transition zone, 

and bedrock and was identified as calcium-bicarbonate water 

type. Continuous ground-water-quality data documented 

seasonal fluctuations and changes during short-term periods 

of increased rainfall. During increased rainfall recorded 

during June–July 2003, water-quality changes in regolith 

well MW-2S showed decreasing specific conductance and 

pH, and increasing dissolved-oxygen concentrations, which 

likely resulted from the infiltration of acidic and dilute rainfall. 

Comparison of ground-water temperatures to air temperatures 

indicated a potential seasonal lag of about 5 months, which 

may be indicative of slow, seasonal infiltration of recharge to 

the shallow part of the ground-water system. 

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separately in alphabetical order and numerical and percent 

change for the United States and Puerto Rico—1990 and 

2000: U.S. Census Bureau, accessed on August 25, 2006, at 

http:// www.census.gov/population/www/cen2000/phc-t29.

html

U.S. Census Bureau, 2004, Charlotte—Center of the nation’s 

4th largest manufacturing region: Charlotte Chamber of 

Commerce Fact Sheet, accessed in August 2007 at http://

www.charlottechamber.com/clientuploads/Economic_pdfs/

FactSheets/Manufacturing_Center.pdf
52 Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at Langtree Peninsula Research Station, 2000–2005

U.S. Census Bureau, 2005, American FactFinder: U.S. Department of Commerce, accessed in June 2007 at 

http://factfinder.census.gov/home/saff/main.html?_lang=en

U.S. Environmental Protection Agency, 2000a, Final radionuclides rule, December 7, available online at 

http://www.epa.gov/safewater/standard/pp/radnucpp.html

U.S. Environmental Protection Agency, 2000b, Proposed 

radon in drinking water rule, EPA 815–F–99–009: available 

online at http://www.epa.gov/safewater/radon/proposal.html

U.S. Geological Survey, 1974, Surface water supply of the 

United States, 1966–70, part 2. South Atlantic Slope and 

Eastern Gulf of Mexico basins, v. 1, Basins from James 

River to Savannah River: U.S. Geological Survey WaterSupply Paper 2104, p. 3–10. 

U.S. Geological Survey, 1975, Quality of surface water of the 

United States, 1970, part 3, Ohio River basin: U.S. Geological Survey Water-Supply Paper 2153, p. 1–2.

U.S. Geological Survey, 1993, Lake Norman North Quadrangle, North Carolina: U.S. Geological Survey 7.5-minute 

series (topographic), scale 1: 24,000. 

U.S. Geological Survey, 2003, North Carolina water-use 

data tables, 2000: U.S. Geological Survey; accessed on 

August 25, 2006, at http://nc.water.usgs.gov/wateruse/data/

Data_Tables_2000.html

Wagner, R.J., Boulger, R.W., Jr., Oblinger, C.A., and Smith, 

B.A., 2006, Guidelines and standard procedures for continuous water-quality monitors: station operation, record 

computation, and data reporting: U.S. Geological Survey 

Techniques and Methods 1–D3, 93 p.; accessible online at 

http://pubs.usgs.gov/tm/2006/tm1D2/

Walters, D.A., Robinson, J.B., and Barker, R.G., 2005, 

Water resources data, North Carolina, water year 2004, 

v. 1—surface-water records: U.S. Geological Survey 

Water-Data Report NC–04–1, 1295 p.; accessible online at 

http://pubs.usgs.gov/wdr/2004/wdr-nc-04/index_sw.html

Walters, D.A., Robinson, J.B., and Barker, R.G., 2006, 

Water resources data, North Carolina, water year 2005, 

v. 1—surface-water records: U.S. Geological Survey 

Water-Data Report NC–05–1, 1090 p.; accessible online at 

http://pubs.usgs.gov/wdr/2005/wdr-nc-05/index_sw.html

Weaver, J.C., 2005, The drought of 1998–2002 in North 

Carolina—Precipitation and hydrologic conditions: 

U.S. Geological Survey Scientific Investigations Report 

2005–5053, 88 p.

Wortman, G.L., Samson, S.D., and Hibbard, J.P., 2000, Precise 

U-Pb zircon constraints on the earliest magmatic history 

of the Carolina terrane: The Journal of Geology, v. 108, 

p. 321–338.
Appendixes

1. Geologic core descriptions from the Langtree Peninsula research station.

(A) Corehole CH-1.

(B) Corehole CH-2.

(C) Corehole CH-3.

(D) Corehole CH-4.

(E) Corehole CH-5.

(F) Corehole CH-6.

(G) Corehole CH-7.

2. Geophysical logs and images showing lithologies and fracture zones tapped by bedrock wells.

(A) Well MW-1D (corehole CH-1).

(B) Well MW-2D (coreholes CH-2 and CH-3).

(C) Well MW-4D (corehole CH-5).

(D) Well MW-5D (corehole CH-6).

(E) Well MW-6D (corehole CH-7).

Appendixes 53
Abbreviations used in Appendix 1:

Dry/Wet

D, dry

M, moist, but no visable water

W, wet

Dry Strength

N, none — The dry specimen crumbles into powder with mere pressure of handling.

L, low — The dry specimen crumbles into powder with some finger pressure.

M, medium — The dry specimen breaks into pieces or crumbles with considerable finger pressure.

H, high — The dry specimen cannot be broken with finger pressure. Specimen will break into pieces between thumb and a hard surface.

VH, very high — The dry specimen cannot be broken between the thumb and a hard surface.

Dilatancy

N, none — No visible change in the specimen.

S, slow — Water appears slowly on the surface of the specimen during shaking and does not disappear or disappears slowly upon 

squeezing.

R, rapid — Water appears quickly on the surface of the specimen during shaking and disappears quickly upon squeezing.

Toughness

L, low — Only slight pressure is required to roll the thread near the plastic limit. The thread and the lump are weak and soft.

M, medium — Medium pressure is required to roll the thread to near the plastic limit. The thread and the lump have medium stiffness.

H, high — Considerable pressure is required to roll the thread near the plastic limit. The thread and the lump have very high stiffness.

Plasticity

N, nonplastic — A 3-millimeter thread cannot be rolled at any water content.

L, low — The thread can barely be rolled and the lump cannot be formed when drier than the plastic limit.

M, medium — The thread is easy to roll and not much time is required to reach the plastic limit. The thread cannot be rerolled after 

reaching the plastic limit. The lump crumbles when drier than the plastic limit.

H, high — It takes considerable time rolling and kneading to reach the plastic limit. The thread can be rerolled several times after reaching the plastic limit. The lump can be formed without crumbling when drier than the plastic limit.

Unified Class (Unified Soil Classification System)

ML — silt

CL — clay

MH — silt of high plasticity, elastic silt

Dip Angle

V — vertical

SV — subvertical

M — medium

SH — subhorizontal

H — horizontal

54 Hydrogeologic Setting, Ground-Water Flow and Quality at the Langtree Peninsula Research Station, 2000–2005
Appendix 1A

REGOLITH LOG SHEET PAGE 1 OF 9

PROJECT: LANGTREE PENINSULA DRILLING METHOD: WIRELINE CORING

BORING ID: CH-1 CORE DIAMETER: 2.25"

LOGGED BY: PIPPIN/CASH/HELLER LATITUDE: 35 31 40.92

BEGIN DATE: LONGITUDE: 80 52 46.80

END DATE: LAND SURFACE ELEVATION: 814.5'

Color descriptions referenced to Munsell soil color charts.

[ft bls, feet below land surface)

I

N

T

E

R

V

A

L

( f

t

b

l

s

)

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

0

1

1

4

4

7

7

8

8

17.5

T

O

T

O

T

O

T

O

T

O

8/22/2000

10/4/2000

B-C D

5YR 5/8 

YELLOW 

RED

S L N ML AS ABOVE W/ MORE DEFINED AND COMMON YELLOWISH 

ZONES

L

t

o

M

A D 10R/4/6 

RED N M M CL

(0-3) 

3' B D 2.5YR4/8 RED N L N MH

(3-8) 

4' B D

5YR4/6 

YELLOW 

RED

S L N

H

M

L

t

o

M

FIRM, HOMOGENEOUS TO BLOCKY, SILTY CLAY W/ ROOT 

FRAGS

FIRM, HOMOGENEOUS TO BLOCKY, CLAYEY SILT TO SILTY 

CLAY. SOME YELLOWISH-RED ZONES AND MINOR ROOT 

FRAGS

ML FIRM, HOMOGENEOUS TO LENSED, CLAYEY SILT W/ MICA 

AND MORE COMMON YELLOWISH RED ZONES

UNIFIED CLASS: CL, clay; MH (American Society for Testing and Materials, 2004)

L

t

o

M

REGOLITH (residuum) (8-13) 

3' C M

5YR 5/8 

YELLOW 

RED

S L N ML SOFT, LENSED TO BLOCKY, SOFT CLAYEY SANDY SILT W/ 

MINOR FE-MN OXIDES

REGOLITH (residuum)

REGOLITH (residuum)

REGOLITH (residuum)

REGOLITH (residuum)
Appendix 1A

REGOLITH LOG SHEET PAGE 2 OF 9

PROJECT: LANGTREE PENINSULA DRILLING METHOD: WIRELINE CORING

BORING ID: CH-1

LOGGED BY: PIPPIN/CASH/HELLER

BEGIN DATE: CORE DIAMETER: 2.25"

END DATE:

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

13

17.5

17.5

27.5

27.5

38.5

38.5

41

8/22/2000

10/4/2000

(13-18) 

2' C M

7.5YR 5/8 

STRONG 

BROWN

N ML

FIRM, STRATIFIED TO LENSED, FIRM CLAYEY SILT W/ 

MORE ABUNDANT MICA AND MN-OXIDES...MICA 

INCREASES W/ DEPTH 

T

O

ML

FIRM, LENSED TO BLOCKY SANDY CLAYEY SILT W/ SOME 

WEAK RED OXIDATION ZONES, MICACEOUS ZONES AND 

MINOR TO MOD. BLACK MN-OXIDES 

T

O

(18-23) 

4' 

(28-33) 

3'

C M

7.5 YR 5/6 

STRONG 

BROWN

L S L

L S L N

L S

L S L N (33-38) 

4' C M

7.5 YR 5/8 

STRONG 

BROWN

T

O

REGOLITH (residuum)

REGOLITH (residuum)

REGOLITH (saprolite)

TRANSITION ZONE

BEDROCK ENCOUNTERED AT 41' - SEE BEDROCK 

LOG SHEETS FOR REMAINDER OF LOG

T

O N ML W/ 

SAND

FIRM, LENSED SANDY SILT W/ NO MN-OXIDES GRADING 

INTO PWR (SAPROLITIC FINE GR. DIORITE) L

ML

SOFT TO FIRM, LENSED SANDY CLAYEY SILT SAPROLITE 

W/ ABUNDANT WHITE CLAY AFTER FELDSPAR AND MNOXIDES (RELICT PHANERITIC TEXTURE - COARSE GR. 

DIORITE)

T

O

(38-41) 

2' C M

7.5 Y 5/4 

LIGHT 

OLIVE 

BROWN
Appendix 1A

BEDROCK LOG SHEET PAGE 3 OF 9

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-1 WIRELINE CORING

LOGGED BY: HELLER/CASH

BEGIN DATE: 8/24/2000 CORE DIAMETER: 2.25"

END DATE: 10/04/2000

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

41 V

SV 2

M

SH

43 H 43-

43 V 1 44.5

SV 1

M 1 45.5

SH 9 46.5

48 H 4 48.5

48 V

SV 1 1 50.0

M 1 3 50.5

SH 51.0

53 H 4

53 V

SV 1

M 3

SH 56.5

58 H 5 58.0

58 V 58.5

SV 1

M 3

SH

63 H 2

4.2 BIOTITE

CONTINUED WEATHERED APPEARANCE UNTIL 58.5' - THEN, FRESH, 

COARSE GR. MASSIVE QUARTZ DIORITE. CHLORITE-EPIDOTE 

REMINERALIZATION AFTER HORNBLENDE OBSERVED.

T

O

BIOTITE

1.5' BIOTITE

WEATHERED, FINE TO MED. GR., DARK GRAY TO OLIVE GRAY, 

MODERATELY FOLIATED QUARTZOFELDSPATHIC BIOTITE, HORNBLENDE 

GNEISS (FOLIATED QUARTZ DIORITE) - FOLIATION IS SUB-VERTICAL.

T

O

T

O

4.2'

WEATHERED TO FRESH, WEAKLY FOLIATED, FINE TO MED. GR., DARK 

GREENISH-GREY QUARTZOFELDSPATHIC BIOTITE- HORNBLENDE 

GNEISS (FOLIATED QUARTZ DIORITE). BECOMES FRESH AT 44.2'. 

FRESH COARSE GR., WHITE TO GREENISH-GRAY TO BLACK, MASSIVE 

QUARTZ DIORITE W/ ACCE

BIOTITE 

QUARTZ

4.8' BIOTITE FRESH WEAKLY FOLIATED TO MASSIVE, DARK GREENISH-GREY, FINE TO 

MED. GR. QUARTZ DIORITE.

T

O

T

O

4.7'

SAME AS ABOVE UNTIL 55.5' - SUBVERTICAL CONTACT W/ RELATIVELY 

FRESH, COARSE GR., MASSIVE QUARTZ DIORITE W/ ACCESSORY PYRITE 

- ROCK BECOMES MORE WEATHERED BEGINNING AT 57'

TRANSITION ZONE

TRANSITION ZONE

TRANSITION ZONE

TRANSITION ZONE

BEDROCK
Appendix 1A

BEDROCK LOG SHEET PAGE 4 OF 9

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-1 WIRELINE CORING

LOGGED BY: HELLER/CASH

BEGIN DATE: 8/24/2000 CORE DIAMETER: 2.25"

END DATE: 10/04/2000

LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

63 V 8

SV 2

M 3

SH 1

68 H 1 4

68 V 68-

SV 69

M 8

SH 4 70-

73 H 1 72

73 V

SV 2

M 8

SH 1

78 H 1

78 V

SV 1

M 1

SH 2

83 H 1 2

83 V 1

SV

M 2

SH

88 H 3

5.3

SAME AS ABOVE - HORNBLENDE-RICH ENCLAVES MORE ABUNDANT 

QUARTZ AND EPIDOTE VEINING OBSERVED FROM 73' TO 75'. MINOR 

BRITTLE REVERSE FAULT @74'-75'. PYRITE, EPIDOTE AND QUARTZ 

BECOMING MORE COMMON (FRESHER ROCK?)

BIOTITE 

QUARTZ

T

O

5.3 SAME AS ABOVE W/ FINE TO MED. GR. ENCLAVES OF MORE 

HORNBLENDE-RICH ROCK @71-72. SMALL PYRITE-BEARING VEIN AT 71.

BIOTITE 

QUARTZ

T

O

4.7 SAME AS ABOVE BIOTITE T

O

T

O

4.8

FROM 83' TO 85' FINE GR. ENCLAVE? OF FINE GR., GRAY-BLACK, 

MODERATELY WELL FOLIATED QUARTZOFELDSPATHIC HORNBLENDE 

GNEISS (FOLIATED DIORITE?). 85' TO 88' SAME AS PREVIOUS INTERVAL. 

BIOTITE 

QUARTZ 

EPIDOTE

T

O

5.2 SAME AS ABOVE BIOTITE

BEDROCK

BEDROCK

BEDROCK

BEDROCK

BEDROCK
Appendix 1A

BEDROCK LOG SHEET PAGE 5 OF 9

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-1 WIRELINE CORING

LOGGED BY: HELLER/CASH

BEGIN DATE: 8/24/2000 CORE DIAMETER: 2.25"

END DATE: 10/04/2000

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

88 V

SV 3

M 7

SH

93 H

93 V

SV 1

M

SH 1 96?

98 H 1 4

98 V

SV 2

M 2

SH 1

103 H 2 4

103 V

SV 1

M 1

SH 2 2

108 H 3

108 V

SV 3

M 3

SH 2

113 H 2 3

BIOTITE 

QUARTZ

T

O 5.5

SAME AS ABOVE - LARGE, NEARLY VERTICAL LEUCOCRATIC 

FRACTURE/VEIN RANGING FROM 1 TO 10 MM IN WIDTH RUNNING 

ALMOST ENTIRE LENGTH OF INTERVAL.

BIOTITE 

QUARTZ

T

O

5.3

CONTINUATION OF QUARTZ VEIN TO 93.5' REMAINDER OF INTERVAL 

SAME AS ABOVE. TWO VERTICLE FRACTURES IN THE 94' TO 95.5' 

INTERVAL. THE REST OF THE FRACTURES ARE H. POSSIBLE ATER 

BEARING ZONE @96'.

BIOTITE T

O

5.2

FRESH, COARSE GR. MASSIVE TO WEAKLY FOLIATED (MOD. DIP) 

QUARTZ DIORITE W/ ACCESSORY PYRITE, EPIDOTE AND CHLORITE. 

FRACTURES ARE MINERALIZED W/ QTZ, EPIDOTE AND CHLORITE?. 

MOST ARE ANNEALED BUT SOME PARTIALLY OPEN >1 MM APERATURE. 

10 CM WIDE QUARTZ VEIN

BIOTITE 

EPIDOTE 

QUARTZ

T

O

BIOTITE T

O 5.5 SAME AS ABOVE

4.6

SAME AS ABOVE, FOLIATION MORE PRONOUNCED, BUT STILL WEAK 

(MOD. DIP). EPIDOTE MORE ABUNDANT. 100.5' TO 102' - FINE GR., GRAYBLACK, MOD. FOLIATED (MOD. DIP) BIOTITE HORNBLENDE GNEISS - 

APPEARS TO BE MORE MAFIC. CONTACTS ARE CLEAN W/ MOD. DIP. 

QTZ. DIOR

BEDROCK

BEDROCK

BEDROCK

BEDROCK

BEDROCK
Appendix 1A

BEDROCK LOG SHEET PAGE 6 OF 9

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-1 WIRELINE CORING

LOGGED BY: HELLER/CASH

BEGIN DATE: 8/24/2000 CORE DIAMETER: 2.25"

END DATE: 10/04/2000

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

113 V

SV 3

M 2

SH 1

118 H 1 3

118 V 118?

SV 119?

M 4

SH 2

123 H 8

123 V

SV

M 2

SH 5

128 H 1 3

128 V

SV

M 4

SH 3

133 H 2

133 V

SV

M 2

SH 2

138 H 3

4.2 SAME AS ABOVE. LEUCOCRATIC VEIN EXTENDS TO 114'. FINER GR. 

INTERVAL W/ MORE AMPHIBOLE FROM 114' TO 116'.

5.3

SAME AS ABOVE TO 126.5' W/ ENCLAVES OF FINER GR., AMPHIBOLERICH ROCK. FROM 126.5' TO 128.5' FINER GR. AMPHIBOLE-RICH 

ENCLAVE? W/ LARGE PLAGIOCLASE FELDSPAR GRAINS. QUARTZ 

VEINING AND MINOR REVERSE FAULTS IN THIS INTERVAL.

T

O

4.8

SAME AS ABOVE W/ SEVERAL HORIZONTAL TO SUBHORIZONTAL 

FRACTURES. 2 VERTICAL QUARTZ VEING APPX. 2-2.5 FT IN LENGTH IN 

THE 129 TO 132' INTERVAL.

BEDROCK

BEDROCK

BEDROCK

BEDROCK

BEDROCK

BIOTITE T

O

BIOTITE T

O

BIOTITE

BIOTITE T

O

BIOTITE 

QUARTZ

T

O

5 SAME AS ABOVE, LEUCOCRATIC VEIN FROM 122' TO 123'.

4.7 SAME AS ABOVE - SOME QTZ VEINING IN THE 136 TO 138 INTERVAL.
Appendix 1A

BEDROCK LOG SHEET PAGE 7 OF 9

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-1 WIRELINE CORING

LOGGED BY: HELLER/CASH

BEGIN DATE: 8/24/2000 CORE DIAMETER: 2.25"

END DATE: 10/04/2000

LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

138 V

SV

M 4

SH 3 1

143 H 2 3

143 V

SV

M 1

SH 3

148 H 2 1

148 V

SV

M

SH 2

152 H 2

152 V

SV

M

SH

157 H 2 3

157 V

SV

M 1

SH 2

163 H 1 1

BIOTITE T

O

BIOTITE T

O

5.2 COARSE GR. DIORITE W/ FINE GR. ENCLAVES AT 145.5 AND 147.5 WEAK 

MOD. DIPPING FOLIATION DEFINED BY ALIGNED AMPHIBOLE. BIOTITE T

O

6.4

FRESH, PORPHYRYTIC, GRAY-BLACK BIOTITE HORNBLENDE GNEISS 

CONT'D. ZONED AND IN SOME CASES TWINNED FELDSPAR 

PORPHYROCLASTS. FELDSPAR-RICH XENOLITHS(?) ALSO OBSERVED. 

FOLIATION BECOMES MORE PRONOUNCED W/ DEPTH, VERY 

PRONOUNCED AT 162. AT 162 - CONTACT W/

4.9

COARSE FELDSPAR ZONE THROUGH 154.5. FINE GR. AMPHIBOLE(?) 

RICH ZONE THROUGH 156.5. FOLIATION WELL DEVELOPED THROUGH 

156. ROCK BECOMES MORE MASSIVE W/ COARSER FELDSPAR AGAIN 

THROUGH 158.

5

SAME AS ABOVE. SOME QUARTZ VEINING, SMALL VUGS IN QUARTZ AT 

141.5. FINE GR. ENCLAVES OF MORE MAFIC ROCK THROUGHOUT 5' 

INTERVAL

4.2

SAME AS ABOVE. ENCLAVE (XENOLITH?) TO 151'. FROM 151' TO 153' 

COARSE GR. FELDSPAR AND FINE GR. AMPHIBOLE. FOLIATION 

OBSERVED FROM 147.5 TO 151. FRACTURING IN THE 152-153 INTERVAL 

SHOWS SOME MINOR DISCOLORATION

T

O

T

O

BEDROCK

BEDROCK

BEDROCK

BEDROCK

BEDROCK
Appendix 1A

BEDROCK LOG SHEET PAGE 8 OF 9

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-1 WIRELINE CORING

LOGGED BY: HELLER/CASH

BEGIN DATE: 8/24/2000 CORE DIAMETER: 2.25"

END DATE: 10/04/2000

LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

163 V

SV

M 1

SH

168 H 1 3

168 V

SV

M 1

SH

173 H 1 4

173 V

SV

M 1

SH

178 H 7

178 V

SV

M 1

SH

183 H 4

183 V

SV

M

SH

188 H 4

5.2

BT HBL GNEISS T0 180.5. W/ ABUNDANT ACCESSORY PYRITE. PYRITE 

AND EPIDOTE MOR ABUNDANT NEAR CONTACT. FROM 180.5 ON, BTGRANITIC GNEISS W/ XENOLITH(?) OR BT HBL GNEISS @182.5. 

FRACTURE AT 182 COATED W/ UNKNOWN WHITE MINERAL W/ 

BOTRYOIDAL(?) SHAPE. 

FINE GR., MOD. FOLIATED BT. HBL GNEISS W/ ACCESSORY EPIDOTE W/ 

10-20 MM BT-GRANITIC ORTHOGNEISS. FOLIATION IS SV TO V.

5.7 BT GRANITIC GNEISS CONT'D W/ MOD TO SV CONTACT W/ BT HBL 

GNEISS @176. 1-2 CM WIDE REACTION RIM ALONG CONTACT.

QUARTZ T

O

4 BT-HBL GNEISS W/ EPIDOTE TO 169'. BT GRANITIC GNEISS FROM 169. 

CONTACT IS INTERLAYERED (INTUSIVE?) - FOLIATION IS SV QUARTZ T

O

5.3

BT GRANITIC GNEISS TO 185.5 - PORPHYRITIC BT HBL GNEISS FROM 

185.5 ON. SV INTRUSIVE CONTACT. FELDSPAR IN BT HBL GNEISS ARE 

COARSER GR. NEAR CONTACT.

5

BIOTITE T

O

BIOTITE T

O

T

O

BEDROCK

BEDROCK

BEDROCK

BEDROCK

BEDROCK
Appendix 1A

BEDROCK LOG SHEET PAGE 9 OF 9

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-1 WIRELINE CORING

LOGGED BY: HELLER/CASH

BEGIN DATE: 8/24/2000 CORE DIAMETER: 2.25"

END DATE: 10/04/2000

LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

188 V

SV

M 2

SH 1

193 H

193 V

SV

M

SH 3

198 H 2

198 V

SV

M

SH

203 H 2

203 V

SV

M

SH

208 H 1 3

208 V

SV

M

SH

209 H

1 SAME AS ABOVE

QUARTZ T

O

T

O

5.2 SAME AS ABOVE W/ THINNER BT GRANITIC INTRUSIONS FROM 203 O 

205.5 - THICKER AGAIN FROM 205.5 TO 208

6

SAME AS ABOVE W/ BT GRANITIC GNEISS INTRUSIONS THICKENING UP 

TO 50 MM. BT HBL GNEISS APPEARS TO BE RATHER MASSIVE IN THIS 

INTERVAL.

T

O

4

PORPHYRITIC BT HBL GNEISS W/ NEARLY VERTICAL STRINGERS (1 TO 20 

MM) OR BT GRANITIC GNEISS. FELDSPAR "PHENOCRYSTS" UP TO 5 MM 

IN LENGTH.

5.3 GRAY-BLACK, PORPHYRITIC BT HBL GNEISS

T

O

T

O

BEDROCK

BEDROCK

BEDROCK

BEDROCK

BEDROCK
Appendix 1B

REGOLITH LOG SHEET PAGE 1 OF 2

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CH-2 CORE DIAMETER: 2.25"

LOGGED BY: LATITUDE: 35 31 32.74

BEGIN DATE: LONGITUDE: 80 52 40.48

END DATE: LAND SURFACE ELEVATION: 797.13'

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

0

0.5

0.5

1

1

3+

VERY LITTLE RECOVER FROM 3 TO 58'. MATERIAL IN END 

OF CORE BARRELS SUGGESTS SAPROLITE (ML) BEGINS 

AT 13' - 18' BLS. MATERIAL IN END OF BARRELS BAGGED - 

TEMPORARY CASING SET AT 58'.

T

O

T

O

T

O

T

O

B D 2.5YR 4/8 

RED S L L

(0-3) 

2.9' A D 2.5YR 4/6 RED N M

L

T

O

M

CL

HARD, MASSIVE STRONGLY CEMENTED SILTY CLAY W/ 

MINOR MICA AND SUBANGULAR QUARTZ PEBBLES UP TO 

3 MM IN DIAMETER

A D

5YR 4/6 

YELLOW 

RED

N M L MH

FIRM, MASSIVE MODERATELY CEMENTED SANDY CLAYEY 

SILT W/ SUBANGULAR QUARTZ COBBLES AND ROOT 

FRAGS

 LANGTREE PENINSULA

HELLER

M

M

T

O

H

M

FIRM, HOMOGENEOUS TO LENSED, MODERATELY WELL 

CEMENTED CLAYEY SILT W/ MORE MICA THAN ABOVE 

AND NO QUARTZ PEBBLES - MICA INCREASES W/ DEPTH - 

MN-OXIDE STAINING BEGINNING AT 2.5'

REGOLITH (residuum)

REGOLITH (residuum)

REGOLITH (residuum)

10/17/2000

10/24/2000
Appendix 1B

BEDROCK LOG SHEET PAGE 2 OF 2

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-2 WIRELINE CORING

LOGGED BY: HELLER

BEGIN DATE:10/17/2000 CORE DIAMETER: 2.25"

END DATE: 10/24/2000

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

58 V 9

SV

M 62-

SH 1 71

63 H

63 V 4

SV 4

M 2

SH 6

68 H 3 4

68 V 2

SV 2

M 1 7

SH

73 H

73 V

SV 10

M 7

SH 1 3

78 H

78 V

SV 1

M 1

SH 2

83 H 1

QUARTZ, 

BIOTITE, 

EPIDOTE

5.3 COARSE GR., FRESH, WEAKLY FOLIATED TO MASSIVE QUARTZ DIORITE 

W/ SOME EPIDOTE/CHLORITE ALTERATION OF HORNBLENDE.

T

O

1

NO RECOVERY FROM 58' TO 61.5'. BEGINNING AT 61.5', FINE GR., 

WEATHERED, MODERATELY FOLIATED (SV) AMPHIBOLITE ABRUPTLY 

CHANGING INTO WEATHERED COARSE GR. WEAK TO MOD. FOLIATED 

(SV) QUARTZ DIORITE W/ 2 EPIDOTE BEARING FRACTURES

T

O

T

O

4.3

WEATHERED, COARSE GR. WEAKLY FOLIATED QUARTZ DIORITE - 

NUMEROUS FRACTURES, MOST WATER BEARING. ANNEALED 

FRACTURES APPEAR TO BE PARTIALLY WEATHERED AWAY AND ALSO 

WATER BEARING. CONTACT AT 68'.

BIOTITE, 

FE 

OXIDES

BIOTITE, 

FE 

OXIDES, 

QUARTZ

2

WEATHERED, FINE GR. WEAKLY TO MODERATELY FOLIATED (M TO SV) 

BIOTITE HORNBLENDE GNEISS W/ ACCESSORY EPIDOTE AND 

ACTINOLITE NOTED - MAY BE MORE SIMILAR, COMPOSITIONALLY, TO 

THE FINE GR. DIORITE NOTED IN THE UPPER PORTION OF CH-1 THAN 

THE BT-HBL GNEISS UNIT 

T

O

T

O

5.4

FRESHER, FINE GR. BT-HBL GNEISS TO 74'. RELATIVELY FRESH, COARSE 

GR. QUARTZ DIORITE BEGINNING @ 74'. LEUCOCRATIC QUARTZ VEIN AT 

76'. A FEW MINOR FAULTS AND MORE INTENSE FRACTURING 

ADJACENT TO QUARTZ VEIN.

TRANSITION ZONE

TRANSITION ZONE

EPIDOTE, 

BIOTITE, 

FE 

OXIDES

QUARTZ, 

FE 

OXIDES, 

EPIDOTE

BEDROCK

TRANSITION ZONE

BEDROCK
Appendix 1C

REGOLITH LOG SHEET PAGE 1 OF 4

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CH-3 CORE DIAMETER: 2.25"

LOGGED BY: LATITUDE: 35 31 35.12

BEGIN DATE: LONGITUDE: 80 52 41.74

END DATE: LAND SURFACE ELEVATION: 800.33'

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

0

0.5

0.5

4

4

9.5

9.5

13

13

18.5

REGOLITH (residuum)

REGOLITH (residuum)

REGOLITH (residuum)

REGOLITH (saprolite)

T

O

T

O

T

O

T

O

T

O REGOLITH (saprolite) (13-18) 

4.6 C M 7.5YR 5/6 BROWN S L

N

P

T

O

L

ML SAME AS ABOVE W/ INCREASED MICA AND KAOLIN AFTER 

FELDSPAR MORE COMMON

(8-13) 

4.4 B-C D

5YR 5/6 

YELLOW 

RED

S L L ML

SOFT TO FIRM, BLOCKY TO LENSED, WEAKLY CEMENTED 

CLAYEY SILT W/ MICA AND MN-OXIDES - SAPROLITIC 

QUARTZ DIORITE

B D

5YR 5/6 

YELLOW 

RED

N

T

O

S

L L MH FIRM SANDY SILTY CLAY TO CLAYEY SILT W/ MORE MICA 

AND SLIGHTLY LENSED APPEARANCE

N

M

T

O

H

L

T

O

M

L

L

M

T

O

H

A-B D 2.5YR 4/6 

RED N

L

T

O

M

N

P

T

O

L

D MH

CL

(0-8) 

5.4 B

 LANGTREE PENINSULA

HELLER

HARD TO VERY HARD MASSIVE SILTY CLAY W/ MINOR 

MICA

FIRM, MASSIVE TO BLOCKY SILTY CLAY W/ ORGANIC 

MATERIAL AND ROOT FRAGS

2.5YR 4/6 

RED TO 

5YR 4/6 

YELLOW 

RED

N L

10/30/2000

11/1/2000
Appendix 1C

REGOLITH LOG SHEET PAGE 2 OF 4

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CH-3

LOGGED BY:

BEGIN DATE: CORE DIAMETER: 2.25"

END DATE:

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

18.5

27.5

27.5

28.5

28.5

39.5

REGOLITH (saprolite)

TRANSITION ZONE

REGOLITH (saprolite)

T

O

(28-33) 

4.7

T

O

(38-

39.5) 

1.6

ML FINE GR. ZONE SIMILAR TO THAT @ 18'. VERY MOIST T

O

(23-28) 

4.4

ML

SOFT TO FIRM, LENSED, WEAKLY CEMENTED SANDY 

CLAYEY SILT - SAPROLITIC QUARTZ DIORITE, LESS 

WEATHERED THAN ABOVE - FINE GR. SANDY CLAYEY 

SILT ZONE, 2.5Y 6/3, @ 18'. ZONE IS 1" THICK AND VERY 

MOIST - PREFERENTIAL PATHWAY?

T

O

C M

2.5Y 6/3 

LIGHT 

YELLOW 

BROWN

N

T

O

L

S L N

P

N

P

(18-23) 

4.4 C M N/A

C M N/A L

N

N

T

O

S

L

 LANGTREE PENINSULA

HELLER

10/30/2000

11/1/2000

ML

FIRM TO HARD, LENSED, WEAKLY TO MODERATELY 

CEMENTED CLAYEY SILT W/ SAND - COARSE GR. QUARTZ 

DIORITE SAPROLITE TO PWR - BECOMES MORE 

COMPETENT W/ DEPTH

T

O

(33-38) 

4.2

R L N

P
Appendix 1C

BEDROCK LOG SHEET PAGE 3 OF 4

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-3 WIRELINE CORING

LOGGED BY: HELLER

BEGIN DATE:10/30/2000 CORE DIAMETER: 2.25"

END DATE: 11/1/2000

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

39.5 V

SV 2

M 1

SH

43 H

43 V

SV 1

M 1 1

SH 3

48 H

48 V

SV 2

M 1 2

SH 1 3 52.5

53 H

53 V 1 55.0

SV 1

M 2 56.5

SH 2 2

58 H 2

58 V

SV

M 2

SH

63 H

BEDROCK

BEDROCK

BEDROCK

BEDROCK

BEDROCK

T

O

BIOTITE 

EPIDOTE 

QUARTZ

5.1 SAME AS ABOVE

BIOTITE 

EPIDOTE 

QUARTZ

BIOTITE 

EPIDOTE 

QUARTZ

5.1 SAME AS ABOVE W/ MINOR BRITTLE FAULT W/ REVERSE MOVEMENT AT 

48.5' 10 CM WIDE BIOTITE-EPIDOTE ANNEALED FRACTURE (M) AT 51.5'.

T

O

T

O

5.1 SAME AS ABOVE - MORE WEATHERED HORIZON @56.5' - ABOUT 0.5' WIDE

49-51

3.9 COARSE GR., RELATIVELY FRESH, MASSIVE TO WEAKLY FOLIATED (M TO 

SV) QUARTZ DIORITE W/ ACCESSORY EPIDOTE - ROCK BEGINS @39.5'

T

O

T

O

4.9 SAME AS ABOVE

BIOTITE 

EPIDOTE 

QUARTZ

BIOTITE 

QUARTZ
Appendix 1C

BEDROCK LOG SHEET PAGE 4 OF 4

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-3 WIRELINE CORING

LOGGED BY: HELLER

BEGIN DATE:10/30/2000 CORE DIAMETER: 2.25"

END DATE: 11/1/2000

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

63 V

SV 1

M 1

SH

68 H

V

SV

M

SH

H

V

SV

M

SH

H

V

SV

M

SH

H

V

SV

M

SH

H

5 SAME AS ABOVE - CORING TERMINATED AT 68' BEDROCK BIOTITE 

EPIDOTE

T

O

T

O

T

O

T

O

T

O
Appendix 1D

REGOLITH LOG SHEET PAGE 1 OF 5

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CH-4 CORE DIAMETER: 2.25"

LOGGED BY: LATITUDE: 35 31 57.09

BEGIN DATE: LONGITUDE: 80 52 53.16

END DATE: LAND SURFACE ELEVATION: 762' 

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

0

0.5

0.5

6

6

11

11

13

13

18

REGOLITH (residuum)

REGOLITH (residuum)

REGOLITH (residuum)

11/7/2000

11/16/2000

T

O

T

O

T

O

T

O

T

O

(13-18) 

5' C M

5YR 5/8 

YELLOW 

RED

S

T

O

R

L N

P ML SAME AS ABOVE W/ MORE ABUNDANT MN-OXIDES - 

REDDISH CLAY-RICH ZONE (2" THICK) AT 16'.

5YR 5/6 

YELLOW 

RED

S L N

P

ML TO 

MH

FIRM, LENSED, MODERATELY CEMENTED SANDY SILTY 

CLAY W/ MORE ABUNDANT MICA THAN ABOVE AND SOME 

FE-MN OXIDES

(8-13) 

1.8' C M

5YR 5/8 

YELLOW 

RED

S L N

P ML FIRM, LENSED, MODERATELY CEMENTED CLAYEY SILT W/ 

ABUNDANT MICA AND MN-OXIDES (DIORITE SAPROLITE)

A M

5YR 4/3 

REDDISH 

BROWN

N L

D L MH

ML TO 

MH

(0-8) 5' B 2.5YR 4/6 

RED N

L

T

O

M

B-C D

L

T

O

M

M

M

T

O

H

L

T

O

M

L

T

O

M

N

P

HOMOGENEOUS TO LENSED, MODERATELY WELL 

CEMENTED SILTY CLAY W/ MICA AND MINOR QUARTZ 

SAND

FIRM, MASSIVE, MODERATELY CEMENTED CLAYEY SILT 

W/ PEBBLES AND ROOT FRAGS

REGOLITH (saprolite)

REGOLITH (saprolite)

 LANGTREE PENINSULA

HELLER
Appendix 1D

REGOLITH LOG SHEET PAGE 2 OF 5

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CH-4

LOGGED BY:

BEGIN DATE: CORE DIAMETER: 2.25"

END DATE:

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

18

19

19

26

26

33

33

38

38

41

REGOLITH (saprolite)

SAME AS 26-33 REGOLITH (saprolite) T

O

(28-33) 

1'

SAME AS 13-18 W/ MORE KAOLINITIC CLAY REPLACING 

FELDSPAR

T

O

C M

5YR 5/8 

YELLOW 

RED

N

P

L N

P

 LANGTREE PENINSULA

HELLER

11/7/2000

11/16/2000

ML

L R L N

P ML

L

R L

N

P

(23-28) 

4.2'

C M

T

O

(18-23) 

2.3'

T

O

C M

5YR 5/8 

YELLOW 

RED

C M 2.5YR 8/1 

WHITE

L

S

T

O

R

L N

P

L R

T

O

(33-38) 

2' C M

5YR 5/8 

YELLOW 

RED

L

5YR 5/8 

YELLOW 

RED

L

S

T

O

R

ML FIRM, LAYERED SANDY CLAYEY SILT (FINE GR. 

QUARTZOFELDSPATHIC SAPROLITE W/ MODERATE DIP)

ML SAME AS 13-18

ML COARSE GR. PEGMATITIC VEIN REGOLITH (saprolite)

REGOLITH (saprolite)

REGOLITH (saprolite)
Appendix 1D

REGOLITH LOG SHEET PAGE 3 OF 5

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CH-4

LOGGED BY:

BEGIN DATE: CORE DIAMETER: 2.25"

END DATE:

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

41

48

48

53

53

58

58

66

66

67

REGOLITH (saprolite)

REGOLITH (saprolite)

REGOLITH (saprolite)

REGOLITH (saprolite)

REGOLITH (saprolite)

SOFT LENSED WEAKLY CEMENTED SANDY CLAYEY SILT 

W/ ABUNDANT WHITE CLAY AFTER FELDSPAR + FE-MN 

OXIDES AFTER AMPHIBOLE? - SAPROLITIC QUARTZ 

DIORITE - MINOR FINE GR. VEIN (MOD. DIP AND 1 CM WIDE 

@ 45'.

T

O

(38-43) 

1.7'

 LANGTREE PENINSULA

HELLER

11/7/2000

11/16/2000

C M L R L N

P

10YR 4/6 

DARK 

YELLOW 

BROWN

ML

(53-58) 

0.5' PWR M N/A L

ML

SOFT TO FIRM, LENSED WEAKLY CEMENTED SANDY 

CLAYEY SILT W/ MORE ABUNDANT MICA THAN ABOVE 

(QTZ DIORITE SAPROLITE)

T

O

(48-53) 

2.5' PWR M N/A L R L

N

P

(43-48) 

2.3'

C TO 

PWR M

2.5 YR 5/2 

GRAYISH 

BROWN

L R L N

P

T

O

ML SAME AS 48-53 T

O

(58-63) 

4.5' PWR M N/A L R L

ML SAME AS ABOVE INTERLAYERED W/ FINE GR. MOD. 

FOLIATED HORNBLENDE GNEISS (SAPROLITIC)

R L

N

P

N

P ML FINE GR. INTERVAL (DIORITE SAPROLITE)

T

O
Appendix 1D

REGOLITH LOG SHEET PAGE 4 OF 5

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CH-4

LOGGED BY:

BEGIN DATE: CORE DIAMETER: 2.25"

END DATE:

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

67

68

68

73

REGOLITH (saprolite)

TRANSITION ZONE

 LANGTREE PENINSULA

HELLER

11/7/2000

11/16/2000

N

P ML COARSE GR. QUARTZ DIORITE W/ EPIDOTE - BECOMING 

HARDER AND FRESHER W/ DEPTH - REFUSAL W/ MUD BIT AT 73'.

T

O

ML SAME AS 48-53 T

O

(68-73) 

4.5' PWR M N/A L R L

L R L N

P

(63-68) 

5.0' PWR M N/A

T

O

T

O

T

O
Appendix 1D

BEDROCK LOG SHEET PAGE 5 OF 5

PROJECT: LANGTREE DRILLING METHOD:

BORING ID: CH-4 WIRELINE CORING

LOGGED BY: HELLER

BEGIN DATE:17/7/2000 CORE DIAMETER: 2.25"

END DATE: 11/16/2000

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

73 V

SV 2

M 2 2 76.0

SH

78 H

78 V

SV

M 3

SH

83 H 2

83 V

SV 85.0

M 6 1

SH 87.5

88 H 1 2 88

88 V 88.5

SV 2 1

M 1 4

SH 1

93 H 1 93.0

93 V 93.5

SV 1 94.5

M 3 96.0

SH 3 97.5

98 H 3

BIOTITE 

QUARTZ

BIOTITE

BEDROCK

TRANSITION 

ZONE/BEDROCK

BEDROCK

BEDROCK

BEDROCK

T

O 3.4 SAME AS ABOVE

BIOTITE 

EPIDOTE 

QUARTZ

BIOTITE 

EPIDOTE

T

O

T

O

5 SAME AS ABOVE - WEATHERED ZONE 88-89. 

2.2 WEATHERED COARSE GR. MASSIVE QUARTZ DIORITE TO 76'. BECOMES 

FRESH AT 76'. VERY LITTLE RECOVERY 72' TO 76'. 

T

O

T

O

5 FRESH COARSE GR. MASSIVE QUARTZ DIORITE

5 SAME AS ABOVE
Appendix 1E

REGOLITH LOG SHEET PAGE 1 OF 3

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CORE DIAMETER: 2.25"

LOGGED BY: LATITUDE: 35 31 44.91

BEGIN DATE: LONGITUDE: 80 52 47.21

END DATE: LAND SURFACE ELEVATION: 801.49'

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

0

0.5

0.5

2

2

5

5

6?

6?

17.5

REGOLITH (residuum)

REGOLITH (residuum)

REGOLITH (residuum)

REGOLITH (residuum)

REGOLITH (residuum)

 LANGTREE PENINSULA

HELLER

N L

L

T

O

M

(0-3) 

2.3' A? M

2.5YR 3/4 

DARK 

REDDISH 

BROWN

M

H

H

H

CL FIRM, MASSIVE, MODERATELY CEMENTED 

HOMOGENEOUS SILTY CLAY W/ ROOT FRAGS

N

P MH

H CL

(3-8) 

2.9' B? M 10R 4/6 RED N L CL

L

T

O

M

N L

L

T

O

M

L

(8-13) 

3.2' B-C? M 2.5YR 4/8 RED

B-C?

(18-23) 

3.3' C M

7.5YR 5/8 

STRONG 

BROWN

L (13-18) 

3.3'

N

T

O

R

M

5YR 5/8 

YELLOW 

RED

R N

P MH-ML

SOFT TO FIRM, WEAKLY TO MOD. CEMENTED CLAYEY 

SILT W/ MINOR SAND. MN OXIDES AND SUB-ANGULAR TO 

ANGULAR, CHEMICALLY WEATHERED, FINE TO MED. GR. 

DIORITE CLASTS (?) W/ EPIDOTE - ONE CLAST BLOCKED 

CORE CATCHER @ 6' (?). 

SOFT TO FIRM, WEAK TO MOD. CEMENTED, POORLY 

LAMINATED (SV DIP) CLAYEY SILT W/ MN-OXIDES. NOTE: 

CONTACT W/ ABOVE HORIZION APPEARS TO BE ABRUPT. 

0' TO 6' COLLUVIUM? ALLUVIUM? FILL?

T

O

T

O

T

O

T

O

T

O

CH-5

2/6/2001

2/7/2001

SOFT TO FIRM, WEAKLY CEMENTED LENSED CLAYEY 

SILT W/ MINOR SAND-MN-OXIDES INCREASING W/ DEPTH

FIRM TO HARD, WELL CEMENTED, HOMOGENEOUS SILTY 

CLAY W/ SMALL, <1MM, ANGULAR TO SUB ANGULAR 

QUARTZ FRAGMENTS
Appendix 1E

REGOLITH LOG SHEET PAGE 2 OF 3

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID:

LOGGED BY:

BEGIN DATE: CORE DIAMETER: 2.25"

END DATE:

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

17.5

30

30

47.5

REGOLITH (saprolite)

REGOLITH 

(saprolite)/ 

TRANSITION ZONE

ML

SOFT, WEAKLY TO MOD. CEMENTED SAPROLITIC TO 

WEATHERED COARSE GR. QUARTZ DIORITE W/ 

AMPHIBOLE AND MICA OBSERVED - SILT W/ SAND 

BECOMES FRESHER GRADUALLY W/ DEPTH - MUD BIT 

REFUSAL @47.5'.

ML

SOFT, WEAKLY TO MODERATELY CEMENTED LENSED 

SILTY CLAY W/ SAND - MN-OXIDES ABUNDANT AND WHITE 

CLAY AFTER FELDSPAR PRESENT - SAPROLITIC DIORITE 

(COARSE GR.) - GRADUAL DECREASE IN WEATHERING W/ 

DEPTH

(28-33) 

3.3'

N

P M

7.5YR 5/8 

STRONG 

BROWN

L S

(23-28) 

3.7'

T

O C

T

O PWR

T

O

 LANGTREE PENINSULA

HELLER

2/6/2001

2/7/2001

L N

P

L R

M

T

O

W

N/A

L

(38-43) 

2.2'

CH-5

T

O

(33-38) 

4.3'

T

O

(43-

47.5) 3'
Appendix 1E

BEDROCK LOG SHEET PAGE 3 OF 3

DRILLING METHOD:

WIRELINE CORING

CORE DIAMETER: 2.25"

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

47.5 V

SV

M 3

SH 2 52?

53 H

53 V

SV

M 6

SH 1 3 56.5?

58 H

58 V 58.5

SV

M 1

SH

63 H 2 1

63 V 64.0

SV

M 1

SH

68 H 3

68 V 68.5

SV 69.0

M 2 70.5

SH 2

73 H 3

BEDROCK

TRANSITION 

ZONE/BEDROCK

BEDROCK

BEDROCK

BEDROCK

QUARTZ 

BIOTITE 

EPIDOTE

5.7' COARSE GR. MASSIVE QUARTZ DIORITE W/ ACCESSORY EPIDOTE - 

RELATIVELY FRESH, BECOMING FRESHER W/ DEPTH

T

O

T

O

4.9' SAME AS ABOVE TO 65'. 65' TO 67', FINER GR. "PORPHYRITIC" INTERVAL. 

SOME MAFIC ENCLAVES (MOD. TO SV ORIENTED) IN THIS INTERVAL 

QUARTZ 

BIOTITE

QUARTZ 

BIOTITE 4.8'

T

O

T

O

5' SAME AS ABOVE - MINOR REVERSE FAULT, MODERATELY DIPPING W/ 1 

CM OFFSET AT 55'.

QUARTZ 

BIOTITE 

EPIDOTE

QUARTZ 

BIOTITE 5.3' COARSE GR. DIORITE 67' TO 70' AND 71.5' TO 73'. FINER GR. 

"PORPHYRITIC" INTERVAL 70' TO 71.5'.

SAME AS ABOVE

T

O

PROJECT: LANGTREE

BEGIN DATE: 2/6/2001

END DATE: 2/7/2001

LOGGED BY: HELLER

BORING ID: CH-5
Appendix 1F

REGOLITH LOG SHEET PAGE 1 OF 2

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CORE DIAMETER: 2.25"

LOGGED BY: LATITUDE: 35 31 48.25

BEGIN DATE: LONGITUDE: 80 52 46.79

END DATE: LAND SURFACE ELEVATION: 783.59'

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

0

1

1

7

7

12.5

12.5

22

22

24

REGOLITH (residuum)

REGOLITH 

(saprolite)/ 

TRANSITION ZONE

REGOLITH (saprolite)

 LANGTREE PENINSULA

HELLER

REGOLITH (residuum)

REGOLITH (residuum)

L

M

T

O

H

H

SOFT TO FIRM, MODERATELY TO WELL CEMENTED, 

BLOCKY SILTY CLAY TO CLAYEY SILT W/ ROOT FRAGS 

AND A FEW SUB-ANGULAR QUARTZ PEBBLES IN THE 

UPPER FEW INCHES

N L L MH

L

L

L N

P ML

(0-3) 

2.5' A M

2.5YR 4/4 

REDDISH 

BROWN

(3-8) 

4.9'

B-C D 2.5YR 5/6 

RED

N

T

O

S

L

SOFT TO FIRM, MODERATELY CEMENTED LENSED 

CLAYEY SILT. MOTTLED APPEARANCE W/ TAN ZONES. 

INCREASED MN-OXIDES

N L

L

T

O

M

CL

C M

5YR 5/8 

YELLOW 

RED TO 

7.5YR 5/6 

STRONG 

BROWN

FIRM TO HARD, WELL CEMENTED, HOMOGENEOUS SILTY 

CLAY W/ MINOR MICA AND MN-OXIDES. B M 10R 4/6 

RED

SOFT, WEAKLY TO MODERATELY CEMENTED CLAYEY 

SILT W/ SAND. LENSED/MOTTLED APPEARANCE. MNOXIDES AND MICA INCREASE W/ DEPTH. SAPROLITIC 

COARSE GR. DIORITE.

(18-24) 

3.9' PWR D N/A S N

P ML SOFT TO FIRM, MODERATELY CEMENTED SILT W/ SAND - 

WEATHERED QUARTZ DIORITE.

S L N

P ML (13-18) 

3.9'

T

O

T

O

T

O

T

O

T

O

(8-13) 

3.7'

CH-6

2/7/2001

2/8/2001
Appendix 1F

BEDROCK LOG SHEET

DRILLING METHOD:

WIRELINE CORING

CORE DIAMETER: 2.25"

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

24 V

SV 3

M 3

SH 3

28 H 1

28 V

SV 5

M 2

SH 4

33 H 1 32.0

33 V

SV

M 1

SH 2 36.0

38 H 2 1

38 V

SV

M

SH

43 H 1

43 V

SV

M 4 45.5

SH 2 46.0

48 H 2

BEDROCK

BEDROCK

BEDROCK

BEDROCK

BEDROCK

SAME AS ABOVE W/ EPIDOTE-PYRITE VEIN (M TO SV, APPX. 2 CM WIDE) 

@27.5'.

PAGE 2 OF 2

QUARTZ 

BIOTITE 

EPIDOTE 

PYRITE

QUARTZ 

BIOTITE 4' COARSE GR. MASSIVE TO WEAKLY FOLIATED, RELATIVELY FRESH 

QUARTZ DIORITE.

PROJECT: LANGTREE

BEGIN DATE: 2/7/2001

END DATE: 2/8/2001

LOGGED BY: HELLER

BORING ID: CH-6

T

O

T

O

5'

T

O

T

O

5.2' FRESH, COARSE GR. WEAKLY FOLIATED (SV DIPPING) QUARTZ DIORITE.

QUARTZ 

BIOTITE 

EPIDOTE 

PYRITE

QUARTZ 

BIOTITE 

EPIDOTE 

PYRITE

5.3'

SAME AS ABOVE- DIORITE IS VARIABLY FOLIATED W/ FOLIATION 

INCREASING FROM TOP TO BOTTOM (SV). VUGGY PYRITE-QUARTZ VEIN 

@35.5'. LAYERED ZONES AT 35.5' AND FROM 37' TO 38'.

QUARTZ 

BIOTITE 

EPIDOTE 

PYRITE

5'

DIORITE 43' - 45', 47' - 48' W/ ACCESSORY PYRITE. FINE GR. MOD. 

FOLIATED (SV) BIOTITE HORNBLENDE GNEISS XENOLITH? FROM 45' - 47'. 

THIS ZONE IS MORE WEATHERED THAN THE DIORITE ABOVE AND BELOW. 

BORING TERMINATED AT 48'.

T

O
Appendix 1G

REGOLITH LOG SHEET PAGE 1 OF 4

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CORE DIAMETER: 2.25"

LOGGED BY: LATITUDE: 35 31 51.57

BEGIN DATE: LONGITUDE: 80 52 45.82

END DATE: LAND SURFACE ELEVATION: 764.64'

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

0

1.5

1.5

5

5

11.5

11.5

13

13

14

REGOLITH (saprolite)

REGOLITH (residuum)

REGOLITH (residuum)

(0-3) 

1.9' A

D

T

O

M

2.5YR 4/4 

REDDISH 

BROWN

REGOLITH (residuum)

M

T

O

H

H

L

L

N L MH

SOFT TO FIRM, MODERATELY TO WELL CEMENTED, 

BLOCKY TO HOMOGENEOUS SILTY CLAY TO CLAYEY SILT 

W/ ROOT FRAGS AND A FEW SUB-ANGULAR TO 

SUBROUND QUARTZ PEBBLES 

N

P

REGOLITH (saprolite)

L

N L

L

T

O

M

CL FIRM TO HARD, WELL CEMENTED, HOMOGENEOUS SILTY 

CLAY W/ SUBANGULAR QUARTZ GRADING INTO BELOW

(3-8) 

4.4' B M 10R 4/6 RED

ML

S L N

P ML

N

T

O

S

L

SOFT, WEAKLY TO MODERATELY CEMENTED CLAYEY 

SILT W/ SAND. LENSED/MOTTLED APPEARANCE. MNOXIDES INCREASE W/ DEPTH. SAPROLITIC COARSE GR. 

DIORITE.

SOFT TO FIRM, MODERATELY CEMENTED LENSED 

CLAYEY SILT. MOTTLED APPEARANCE W/ TAN ZONES. 

MINOR MN-OXIDES

M

7.5YR 5/8 

STRONG 

BROWN

M

7.5YR 5/8 

STRONG 

BROWN

(8-13) 

4.5' B-C D

5YR 5/8 

YELLOW 

RED

(18-23) 

3.9' C

(13-18) 

4.1'

FINER GR. INTERVAL - SOFT CLAYEY SILT W/ SLIGHTLY 

LAYERED APPEARANCE S L N

P ML

T

O

T

O

T

O

T

O

T

O L

C

CH-7

2/20/2001

 LANGTREE PENINSULA

HELLER

2/20/2001
Appendix 1G

REGOLITH LOG SHEET PAGE 2 OF 4

PROJECT: DRILLING METHOD: WIRELINE CORING

BORING ID: CORE DIAMETER: 2.25"

LOGGED BY:

BEGIN DATE:

END DATE:

Color descriptions referenced to Munsell soil color charts.

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

S

O

I

L

H

O

R

I

Z

O

N

D

R

Y

/

W

E

T

C

O

L

O

R

D

R

Y

S

T

R

E

N

G

T

H

D

I

L

A

T

A

N

C

Y

T

O

U

G

H

N

E

S

S

P

L

A

S

T

I

C

I

T

Y

U

N

I

F

I

E

D

C

L

A

S

S

 DESCRIPTION 

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

14

17

17

20.5

20.5

26

REGOLITH (saprolite)

REGOLITH (saprolite)

REGOLITH 

(saprolite)/ 

TRANSITION ZONE

2/20/2001

(23-28) 

4' C M

7.5YR 5/8 

STRONG 

BROWN

 LANGTREE PENINSULA

CH-7

HELLER

2/20/2001

N

P ML SAME AS 14-17 BUT W/ WHITE CLAY AFTER FELDSPAR TO

ML SAME AS 11.5 TO 13 W/ MORE MICA T

O

(3-8) 

4.4' C M

7.5YR 5/8 

STRONG 

BROWN

L S L

L S L N

P

T

O

T

O

ML

BECOMING MORE FRESH W/ MORE RESISTANT DIORITIC 

ZONES - RELICT AMPHIBOLE VISIBLE AT THE END OF THE 

RUN - REFUSAL AT 26'.

T

O L S L N

P

(8-13) 

4.5' PWR M

7.5YR 5/8 

STRONG 

BROWN
Appendix 1G

BEDROCK LOG SHEET

DRILLING METHOD:

WIRELINE CORING

CORE DIAMETER: 2.25"

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

26 V

SV 1

M

SH

28 H

28 V

SV 4

M 2

SH 2

33 H 6

33 V

SV

M 4

SH 1

38 H 6

38 V

SV 1

M 2

SH 2

43 H 5

43 V 1

SV 2

M 2 1

SH

48 H 7

PAGE 3 OF 4

EPIDOTE 

FE-OXIDE

EPIDOTE 

FE-OXIDE TRANSITION ZONE

TRANSITION ZONE

T

O

3.9

WEATHERED BIOTITE HORNBLENDE GNEISS TO 31'. WEATHERED 

COARSE GR., WEAKLY FOLIATED TO MASSIVE QUARRTZ DIORITE FROM 

31' TO 33'. QUARTZ VEIN AT 31'.

1.5' WEATHERED, FINE GR. WEAKLY TO MOD. FOLIATED BIOTITE 

HORNBLENDE GNEISS

PROJECT: LANGTREE

BEGIN DATE: 2/20/2001

END DATE: 2/20/2001

LOGGED BY: HELLER

BORING ID: CH-7

T

O

T

O

5.2 LESS WEATHERED QUARTZ DIORITE W/ FINE GR. XENOLITH OF BIOTITE 

HORNBLENDE GNEISS @38-39'.

QUARTZ 

BIOTITE 

EPIDOTE 

PYRITE

EPIDOTE 

FE-OXIDE 3.9

WEATHERED QUARTZ DIORITE W/ FINE GR. XENOLITHS OF BIOTITE 

HORNBLENDE GNEISS @ 35.5' AND 37'. THESE ZONES SEEM TO BE 

MORE WEATHERED THAN SURROUNDING DIORITE AND MORE 

SATURATED W/ WATER

T

O

T

O 5.3 QUARTZ DIORITE, BECOMING FRESHER W/ DEPTH

TRANSITION ZONE/ 

BEDROCK

BEDROCK

TRANSITION ZONE

BIOTITE 

QUARTZ
Appendix 1G

BEDROCK LOG SHEET

DRILLING METHOD:

WIRELINE CORING

CORE DIAMETER: 2.25"

 LITHOLOGIC DESCRIPTION FRACTURE INFO

I

N

T

E

R

V

A

L

R

E

C

O

V

E

R

Y

DESCRIPTION

#

A

N

N

E

A

L

E

D

#

O

P

E

N

H

2

0

B

E

A

R

I

N

G

M

I

N

E

R

A

L

S

G

r

o

u

n

d

-

W

a

t

e

r

Z

o

n

48 V

SV 1

M 3

SH 3

53 H 11

PAGE 4 OF 4

PROJECT: LANGTREE

BORING ID: CH-7

LOGGED BY: HELLER

BEGIN DATE: 2/20/2001

END DATE: 2/20/2001

4.7

T

O

T

O

T

O

T

O

T

O

COARSE GR. MASSIVE TO WEAKLY FOLIATED, RELATIVELY FRESH 

QUARTZ DIORITE.

QUARTZ 

BIOTITE BEDROCK
0 90

Fracture/Foliation

Dip angle (degrees)

DEPTH, IN FEET BELOW LAND SURFACEDEPTH, IN FEET BELOW LAND SURFACE

6 8

Caliper (inch)

Res (16N) (OHM-M)

1,000 4,000

Res (64N) (OHM-M)

1,000 4,000

Res (FL) (OHM-M)

63 66

0 2,000

-0.03 0.03

-1 1

Flow - ambient

Heat Pulse Flowmeter

(gal/min)

Flow - pumping

0

25

50

75

100

125

150

175

200

225

250

275

300

325

350

375

400

425

450

475

500

525

550

575

600

0

25

50

75

100

125

150

175

200

225

250

275

300

325

350

375

400

425

450

475

500

525

550

575

600

Optical Televiewer Image

0 0 90 180 270

GAM(NAT) (API-GR)

0 400

Temperature 

(Degrees Fahrenheit)

Appendix 2A. Geophysical logs for bedrock well MW-1D at the Langtree Peninsula research station, North Carolina.

See corehole CH-1 description in Appendix 1.

N E S W N

Ambient

inflow

Pumping

inflow

*Image obtained

in 6-inch

diameter well 

Ambient

inflow

Ambient

outflow

Note: pump was 

set at 60 feet 

N

S

EW

Example of tadpole

showing dip azimuth

Secondary fracture

Primary fracture

Foliation

Ambient

Pumping

EXPLANATION

Water level

Water-bearing 

stress-relief

fracture

(transition zone)

50 gal/min
0 0 90 0 90 6 7  180 270

Caliper (inch)

GAM(NAT) (API-GR)

55 62

255 270

RES (FL) (OHM-M)

0 100

340

360

380

400

20

0

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

340

360

380

400

20

0

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

Fracture/Foliation

Dip angle (degrees)

Temperature 

(Degrees Fahrenheit)

-0.12 0.12

-0.5 0.5

Flow - ambient

Flow - pumping

Heat Pulse Flowmeter

(gal/min)

N

S

EW

Example of tadpole

showing dip azimuth

Appendix 2B. Geophysical logs for bedrock well MW-2D at the Langtree Peninsula research station, North Carolina.

See coreholes CH-2 and CH-3 descriptions in Appendix 1.

Optical Televiewer Image

N E S W N

Water-bearing

stress-relief

fracture

Note: pump was 

set at 35 feet 

Camera

Line

Secondary fracture

Primary fracture

Foliation

Ambient

Pumping

EXPLANATION

Water level

DEPTH, IN FEET BELOW LAND SURFACEDEPTH, IN FEET BELOW LAND SURFACE

*Image obtained

in 6-inch

diameter well 

Water-bearing

stress-relief

fracture

Pumping

inflow

Ambient

inflow

Ambient

outflow

Downflow

inflow
Res (FL) (OHM-M)

0 0 10  0 90 0 90 6 7  180 270

Caliper (inch) 

GAM(NAT) (API-GR)

Res (16N) (OHM-M) 

0 4,000

Res (64N) (OHM-M) 

0 4,000

62 63

-0.5 0.5

-0.04 0.04

Flow - ambient

Flow - pumping

0 100 

250

225

275

300

325

350

375

400

25

0

50

75

100

125

150

175

200

250

225

275

300

325

350

375

400

25

0

50

75

100

125

150

175

200

Optical Televiewer Image Fracture/Foliation 

Dip angle (degrees) 

Temperature 

(Degrees Fahrenheit) 

N

S

EW

Example of tadpole

showing dip azimuth

Heat Pulse Flowmeter

(gal/min)

Appendix 2C. Geophysical logs for bedrock well MW-4D at the Langtree Peninsula research station, North Carolina.

 See corehole CH-5 desciption in Appendix 1.

N E S W N

DEPTH, IN FEET BELOW LAND SURFACEDEPTH, IN FEET BELOW LAND SURFACE

*Image obtained

in 6-inch

diameter well 

Pumping

inflow

Ambient

inflow

Pumping

inflow

Ambient

outflow

Ambient

inflow

Water-bearing

stress-relief fractures

Water-bearing

parting-plane

fracture

Note: pump was 

set at 52 feet 

Camera

Line

Secondary fracture

Primary fracture

Foliation

Ambient

Pumping

EXPLANATION

Water level
Heat Pulse Flowmeter

(gal/min)

0 90 6 7.5 

Dip angle (degrees) Caliper (inch) Res (64N) (OHM-M)

0 4,000

Res (16N) (OHM-M)

0 4,000

0 150

RES (FL) (OHM-M)

-1.5 1.5

-0.04 0.04

Flow - ambient

Flow - pumping

250

225

275

300

325

350

375

400

25

50

75

100

125

150

175

200

250

225

275

300

325

350

375

400

25

0 0

50

75

100

125

150

175

200

N

S

EW

Example of tadpole

showing dip azimuth

Appendix 2D. Geophysical logs for bedrock well MW-5D at the Langtree Peninsula research station,

 North Carolina. See corehole CH-6 description in Appendix 1.

Optical Televiewer Image

0 50

Gamma Log (APIU)

0 0 90 180 270

N E S W N

Water-bearing

stress-relief fractures

*Image obtained

in 6-inch

diameter well 

Downflow

61 63

Temperature 

(Degrees Fahrenheit) 

Note: pump was 

set at 31 feet 

Camera

Line

Secondary fracture

Primary fracture

Foliation

Ambient

Pumping

EXPLANATION

Water level

DEPTH, IN FEET BELOW LAND SURFACE

Pumping

inflow

Ambient

outflow

Ambient

inflow

Pumping

inflow

DEPTH, IN FEET BELOW LAND SURFACE

Inflow

Inflow
0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

250

260

270

280

290

300

310

320

330

340

350

360

370

380

390

400

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

250

260

270

280

290

300

310

320

330

340

350

360

370

380

390

400

-0.03 0.03

N

S

W E

Example of tadpole

showing dip azimuth

Optical Televiewer Image

0 600

Gamma Log (APIU)

0 0 90 180 270

N E S W N

0 90

Fracture/Foliation

Dip angle (degrees)

6 8

Caliper (inch)

Res (64N) (OHM-M)

0 4,000

Res (16N) (OHM-M)

0 4,000

Res (FL) (OHM-M)

62 66

Temperature 

(Degrees Fahrenheit)

0 10 -1 1

Flow - ambient

Flow - pumping

Heat Pulse Flowmeter

(gal/min)

Appendix 2E. Geophysical logs for bedrock well MW-6D at the Langtree Peninsula research station, North Carolina.

 See corehole CH-7 description in Appendix 1.

DEPTH, IN FEET BELOW LAND SURFACEDEPTH, IN FEET BELOW LAND SURFACE

*Image obtained

in 6-inch

diameter well 

Water-bearing stress-relief

fractures

Pumping

inflow

Ambient

outflow

Ambient

inflow

Downflow

Note: pump was 

set at 25 feet 

Secondary fracture

Foliation

Ambient

Pumping

EXPLANATION

Water level
Prepared by:

USGS Enterprise Publishing Network

Raleigh Publishing Service Center

3916 Sunset Ridge Road

Raleigh, NC 27607

For additional information regarding this publication, contact:

Melinda J. Chapman, Ground-Water Specialist

USGS North Carolina Water Science Center

3916 Sunset Ridge Road

Raleigh, NC 27607

phone: 919-571-4047

email: mjchap@usgs.gov

Or visit the North Carolina Water Science Center website at:

http://nc.water.usgs.gov

This publication is available online at:

http://pubs.water.usgs.gov/sir2008-5055
Printed on recycled paper

Pippin and others—Hydrogeologic Setting, Ground-Water Flow, and Ground-Water Quality at the Langtree Peninsula Research Station—Scientific Investigations Report 2008–5055