Ground-Water Resources 

of Olmsted Air Force Base 

Middletown, Pennsylvania

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1539-H

Prepared for the Corps of Engineers, 

U.S. Army

I AN 191962

Ground-Water Resources 

of Olmsted Air Force Base 

Middletown, Pennsylvania

By HAROLD MEISLER and STANLEY M. LONGWILL

CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES 

GEOLOGICAL SURVEY WATER-SUPPLY PAPER 1539-H

Prepared for the Corps of Engineers, 

U.S. Army

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1961
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington 25. D.G.
CONTENTS

	Page 

Abstract______________________________________________________ H-l

Introduction. _____________________________________________________ H-l

Purpose of the investigation.___________________________________ H-l

Location and geographic setting.________________________________ H-2

Methods of investigation.______________________________________ H-3

Previous investigations.________________________________________ H-3

Acknowledgments. ____________________________________________ H-3

Geology_____________.____________________________ H-3

General features_____________________________________________ H-3

Stratigraphy ______________-_____--__________-___-_--_--_-_-___ H-4

Structure, ____________________________________________________ H-8

Alluvial deposits______________-________-_--_-__-__-_---_-___ H-8

Ground-water hydrology___________________________________________ H-8

Principles___ _ _______________________________________________ H-8

Warehouse area_______________________________________________ H-l3

Main base.___________________________________________________ H-14

Geochemistry_____________________________________________________ H-28

Conclusions_____________________________________________________ H-33

References cited.__________________________________________________ H-34

ILLUSTRATIONS

Page 

FIGURE 1. Map of southeastern Pennsylvania showing location of Olmsted Air Force Base_--___-_________--________-___--__ H-2

2. Map showing location of wells__________________________ H-4

3. Electrical-resistivity logs of wells Da-93 and Da-77 at Olmsted Air Force Base___________________________________ H-7

4. Logarithmic graph of drawdown in a typical well penetrating

a theoretical aquifer of infinite extent ___________________ H-10

5. Logarithmic graph of drawdown showing effect of a recharging

boundary in a theoretical aquifer of infinite extent______ H-ll

6. Logarithmic graph of drawdown showing effect of an Impermeable boundary in a theoretical aquifer of infinite extent. H-12

7. Cross section showing relation of strata penetrated by wells

in warehouse area, Olmsted Air Force Base_ _____________ H-14

8. Logarithmic graph of drawdown in well Da-78_____________ H-15

9. Logarithmic graph of recovery in well Da-78______________ H-16

10. Cross section showing relation of strata penetrated by wells

in eastern part of Olmsted Air Force Base.______________ H-18

11. Logarithmic graph of drawdown in well Da-80_____________ H-19

12. Logarithmic graph of drawdown in well Da-82_____________ H-20

13. Logarithmic graph of drawdown in well Da-83_____________ H-21

in
IV CONTENTS

Page 

FIGURE 14. Logarithmic graph of recovery in well Da-87 ______________ H-23

15. Cross section showing relation of strata penetrated by wells

in western part of Olmsted Air Force Base_______________ H-24

16. Logarithmic graph of recovery in well Da-88-_____________ H-25

17. Logarithmic graph of recovery in well Da-90 ______________ H-26

18. Logarithmic graph of recovery in well Da-91 ______________ H-27

19. Trilinear diagram showing chemical character of ground

water at Olmsted Air Force Base.______________________ H~32

TABLES

Page 

TABLE 1. Hydrologic characteristics of wells on Olmsted Air Force Base. H-17

2. Chemical analyses of water from wells on Olmsted Air Force

Base.___________________________._____________ H-28

3. Change of hardness and specific conductance during pumping

of wells___---______-______________-----__-_________ H-30

4. Comparison of the chemical character of ground water in the

three areas of the main base___--___-_-----_---_-----__- H-31
CONTRIBUTIONS TO THE HYDROLOGY OF THE UNITED STATES

GROUND-WATER RESOURCES OF OLMSTED 

AIR FORCE BASE,

MIDDLETOWN, PENNSYLVANIA

By HAROLD MEISLER and STANLEY M. LONGWILL

ABSTRACT

Olmsted Air Force Base is underlain by the Gettysburg shale of Triassic age. 

The Gettysburg shale at the Air Force Base consists of interbedded red sandstone, siltstone, and shale. The average strike of the strata is N. 43° E., and the 

strata dip to the northwest at an average angle of 26°.

The transmissibility of known aquifers in the warehouse area of the Air Force 

Base is low. Therefore, wells in the warehouse area have low specific capacities 

and yield only small supplies of water. Wells on the main base, however, yield 

relatively large supplies of water because the transmissibilities of the aquifers 

are relatively high. Pumping tests in the warehouse area and the eastern area 

of the main base indicated the presence of impermeable boundaries in both areas. 

Pumping tests in the central and western parts of the main base revealed that 

the Susquehanna River probably is acting as a source of recharge (forms a 

recharge boundary) for wells in those areas.

Data obtained during this investigation indicate that additional supplies of 

ground water for Olmsted Air Force Base could best be obtained from the 

western part of the main base.

INTRODUCTION

PURPOSE OP THE INVESTIGATION

The investigation described in this report was made by the U.S. 

Geological Survey in response to a request for the Corps of Engineers, 

U.S. Army, to help locate an adequate water supply for the new warehouse area of Olmstead Air Force Base, Middletown, Pa. The investigation was to answer the following questions: (a) What geologic 

factors affect the yield of wells? (b) Where are the most favorable 

Avell sites and what are the recommended well depths and optimum 

pump settings necessary for producing a yield of 640 gpm (gallons 

per minute) from wells in the warehouse area? (c) What are the 

possibilities of obtaining the water needed by increasing the yield from

H-l
H-2 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

one or more existing wells on the Air Force Base? (d) What would 

be the effect of new wells on existing wells ?

The investigation was under the immediate supervision of Joseph 

E. Barclay, district geologist, Harrisburg, Pa.

LOCATION AND GEOGRAPHIC SETTING

Olmsted Air Force Base lies just west of Middletown, Pa., in 

south-central Dauphin County, at lat 40° 12' N.; long 76°45' W. (See 

fig. 1.) The main part of the base is bordered on the south by the

77°00' '' \

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FIGURE 1. Map of southeastern Pennsylvania showing location of Olmsted Air Force Base.

Susquehanna River and on the north by U.S. Highway 230. The 

warehouse area, now under development, is bordered on the south by 

U.S. Highway 230 and on the north by the Pennsylvania Turnpike.

Olmsted Air Force Base is in the Triassic lowland of the Piedmont 

province. The Triassic lowland is characterized by a gently undulating surface which slopes generally to the south and is traversed by 

many ridges of diabase.

Altitudes on the Air Force Base range from 280 feet above mean 

sea level at the Susquehanna River to 385 feet at the northern boundary. The main part of the base is on an alluvial terrace along the 

Susquehanna River, at an altitude of approximately 300 feet. This 

terrace was named the Binghamton terrace by Peltier (1949). The 

present flood plain has apparently been filled in to the level of this 

terrace in the vicinity of the Air Force Base. North of the main base
GROUND-WATER RESOURCES, OLMSTED AIR FORCE BASE H-3

the land surface rises abruptly; in the warehouse area there are 

remnants of two higher terraces at altitudes of 360 and 380 feet.

METHODS OF INVESTIGATION

Fieldwork for this investigation was begun on January 19, 1959, 

and completed on February 6, 1959. An inventory was made of 

existing wells on the Air Force Base and in part of the surrounding 

territory, and pumping tests were made on 3 wells (fig. 2) on the 

main base and 1 well in the warehouse area. A brief geologic 

investigation of the area was made in order to determine local stratigraphy and structure, and rock samples from well Da-77 (see sample 

log, below) in the new warehouse area were studied with the aid of 

a binocular microscope. Chemical analyses of 43 water samples from 

14 wells on the Air Force Base were made by the Quality of Water 

Laboratory of the Geological Survey, Philadelphia, Pa. Electric 

and gamma-ray logs were obtained from 1 well on the main base and 

from 3 wells in the warehouse area. The electric logs include curves 

showing self potential, single-point resistance, 16- and 64-inch normal 

resistivity, and fluid resistivity.

PREVIOUS INVESTIGATIONS

The geology and ground-water resources of southeastern Pennsylvania were described by Hall (1934). The geology of the Middletown quadrangle, which includes the eastern part of Olmsted Air 

Force Base, was discussed in a report by Stose and Jonas (1933).

ACKNOWLEDGMENTS

Acknowledgment is due Mr. Eussell Conrad of the Air Installations 

Office, U.S. Air Force, for supplying data on the wells on Olmsted 

Air Force Base.

GEOLOGY

GENERAL FEATURES

Olmsted Air Force Base is underlain by the Gettysburg shale, 

which is part of the Newark group of Triassic age. The Gettysburg 

shale in its type locality at Gettysburg, Pa., consists of soft red 

shale and soft red sandstone (Stose and Jonas, 1933). The Newark 

group as a whole occupies a series of disconnected, downf aulted basins 

that extend from Nova Scotia to North Carolina. In Pennsylvania 

the Newark group is part of the largest Triassic basin in the eastern 

United States a basin which extends from New Jersey to Virginia.
H-4 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

N Da-78. .Da-77

Da-95' 

Da-79.

Da-96 

Da-94

Da-9L

,Da-90

.Da-97 

 Da-98

Da-85'

Da-88* ,Da-93 .Da-92

Da-87*

 Da-89

Da-83« 

Da-81* 

Da-80

.Da-84 

*Da-82

EXPLANATION

 Da-90 

Well

26

Average strike and 

dip of strata

V* MILE

FIGURE 2. Map showing location of wells.

The Newark group consists of conglomerate, sandstone, arkose, 

siltstone, shale, argillite, and lava flows. The sedimentary rocks of 

the group are intruded by diabase dikes and sills. In the general 

area of Olmsted Air Force Base, the Newark group is divided into 

the New Oxford formation and the overlying Gettysburg shale.

The Triassic rocks in southeastern Pennsylvania dip generally to 

the northwest at angles ranging from 10° to 50°. Large faults form 

the northern boundary of the basin.

STRATIGRAPHY

The Gettysburg shale on Olmsted Air Force Base consists of alternating beds of red sandstone, siltstone, and shale. The beds of sand-
GROUND-WATER RESOURCES, OLMSTED AIR FORCE BASE H-5

stone and siltstone are poorly sorted and weakly cemented with calcium 

carbonate. Quartz grains, ranging in size from silt to very small 

pebbles, and red clay are the chief constituents of the formation. 

The siltstone is sandy and contains substantial amounts of clay, and 

most of the sandstone contains considerable amounts of both silt and 

red clay. Little pure shale is present. As most of the rocks are composed of the same materials (differing from one another only in the 

proportion of constituents) they appear to be uniform in composition 

unless they are examined in detail.

The following sections and the log of Da-77 show the complex 

interbedded nature of the sedimentary rocks.

Section exposed at Ca-pehart housing unit, 1,600 feet north of U.S. Route 230

Thickness 

(feet)

Siltstone, red, sandy, clayey_________________________ 4

Sandstone, red, fine-grained, very clayey___________________ 4

Siltstone, red_____________________________________ 3. 5

Sandstone, red, medium-grained, clayey, friable_______________ 3

Shale, red_____________________________________ 2

Sandstone, red, very fine to fine-grained, clayey __ ___ _ 2. 5

Section exposed in gutter along road in southern part of warehouse area, 

sampled every 5 feet of thickness

Sample taken 

at 

(feet)

Siltstone to very fine grained sandstone, red, shaly_____________ 5-15

Shale, red_____________________________________ 20

Siltstone, red, shaly_________________________________ 25

Sandstone, red, fine- to medium-grained, clayey________________ 30-35

Siltstone to very fine grained sandstone, red, shaly____________ 40

Shale, red______________________________________ 45

Siltstone to very fine grained sandstone, red, shaly______ __ __ 50

Siltstone, red, coarse, sandy________________________-_ 55

Sandstone, red, fine- to medium-grained, clayey_______________ 60-65

Sandstone, red, fine-grained, clayey_____________ ___ _ 70-80

Siltstone, red_____________________________________ 85

Sandstone, red, fine- to coarse-grained, clayey_______________ 90

Siltstone, red, sandy______________________________ __ 95

Sandstone, red, very fine grained, clayey_____________-___ 100-110

Siltstone, red, sandy, shaly_____________________ ___ 115-150

Sandstone, red, very fine grained, clayey- _ _ 155

Sandstone, orange, medium- to coarse-grained, feldspathic 160

Sandstone, red, medium-grained____________________ _ 165

Sandstone, red, fine-grained, clayey_______________ 170

Siltstone to very fine grained sandstone, red__________ 175

602547 61-
H-6 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

Sample log of well Da-77, warehouse area, Olmsted Air Force Base

Depth 

(feet)

Siltstone, red, sandy, quartz grains, calcareous; also some fine-grained 

angular quartz and poorly sorted sandstone________________ 100-110

Siltstone, red, as above; soft clay pocket encountered by drill _ 110-120 

Siltstone, red, as above; some medium and coarse quartz sand- ___ 120-130 

Siltstone, red, as above_____________________________ 130-140 

Siltstone, red, as above; some medium and coarse quartz sand _____ 140-150 

Shale, red; a little coarse quartz sand__________________ 150-160 

Sandstone, red, fine- to medium-grained, quartz, subangular, fairly well

sorted, calcareous_______________________________ 160-180 

Sandstone, medium grained, as above; a little red shale__________ 180-200 

Sample missing___________________________________ 200-210 

Sandstone as above; red siltstone and shale________________ 210-220 

Sandstone as above; a little red siltstone__________ _ 220-230 

Siltstone, red; some sandstone; a little red shale; soft clay pocket encountered by drill_________________________________ 230-240 

Siltstone, red, as above_____________________________ 240-270 

Siltstone, red, as above; a little coarse quartz sand_____ __ 270-280 

Sandstone, fine- to medium-grained, as above; red siltstone as above 280-300 

Sandstone, medium- to coarse-grained; red siltstone as above; calcite or

limestone _____________________________________ 300-310 

Siltstone, red; sandstone___________________________ 310-320 

Siltstone, red; some sandstone__________________________ 320-330 

Sandstone, medium-grained; siltstone_____________________ 330-350 

Sandstone, fine- to medium-grained; red siltstone____________ 350-360 

Sandstone, medium- to coarse-grained; little siltstone___________ 360-370 

Sandstone, coarse-grained; little siltstone________________ 370-390

Sandstone, coarse-grained; siltstone________________-_ 390-400 

Siltstone, red ; medium- to coarse-grained sandstone_____ _ 400-420 

Sandstone, medium- to coarse-grained; some red siltstone_ _ 420-440 

Sandstone, medium- to coarse-grained; some red siltstone; a little red

shale ______________________________________ 440-450 

Sandstone, medium-grained ; some red siltstone________ _ 450-460 

Sandstone, medium- to coarse-grained; some red siltstone_________ 460-480 

Siltstone, sandy, red; medium- to coarse-grained sandstone_ _ 480-490 

Sandstone, medium- to coarse-grained; red siltstone___ _ 490-500 

Sandstone, medium- to coarse-grained; some red siltstone_ ___ 500-510 

Sandstone, fine- to medium-grained; some red siltstone__ _ 510-530 

Sandstone, coarse-grained; some siltstone__________ - 530-540 

Siltstone, red; some sandstone____________ __ 540-550 

Sandstone, medium- to coarse-grained; some red siltstone _ _ 550-560 

Sandstone, medium- to coarse-grained; some red siltstone and calcite 560-570 

Siltstone, red___________________________________ 570-580 

Sandstone, medium-grained; red shale and siltstone____ _ 580-590 

Sandstone, medium- to coarse-grained; some siltstone and shale-_ 590-600 

Sandstone, medium- to coarse-grained; some red siltstone 600-640 

Sandstone, medium-grained, red siltstone___________ _ 640-650 

Siltstone, red; fine- to medium-grained sandstone ____ _ 650-660 

Siltstone, red; clay pocket encountered by drill at 675 ft 660-690
GROUND-WATER RESOURCES, OLMSTED AIR FORCE BASE H-7

Electrical-resistivity logs from the Air Force Base show that electrically most of the rocks in the area are fairly uniform. The rocks 

have a fairly low electrical resistivity, which indicates a high clay 

content. Variations in resistivity do occur, apparently because of 

lithological changes such as decreased clay content or greater degree 

of cementation and density of the rock. Figure 3 shows electrical100

200

300

S 400

Q. 

LU

Q

500

600

700

800

Da-93

RESISTIVITY, IN OHM-METERS 

200 600 1000 1400 1800

Da-77

RESISTIVITY, IN OHM-METERS 

200 600 1000 1400 1800

 16-inch normal curve 

--. -64-inch normal curve

FIGURE 3. Electrical-resistivity logs of wells Da-93 and Da-77 at Olmsted Air

Force Base.
H-8 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

resistivity logs of well Da-93 (AFB-14), on the main base, and well 

Da-77, in the warehouse area. An increase in resistivity take place at 

300 feet in Da-77 and is interpreted as indicating a greater proportion 

of sandstone below that depth. The log of Da-93 (AFB-14), on the 

main base, shows distinct zones of high resistivity at depths of 250, 

690, and 750 feet. These zones are believed to be occupied by beds of 

water-bearing sandstone that contain very little clay. The logs from 

the warehouse area show no zones of comparably high resistivity; 

therefore, beds of relatively clay-free sandstone are believed to be 

absent near the wells in that area.

STRUCTURE

Beds of the Gettysburg shale at Olmsted Air Force Base dip to the 

northwest at angles ranging from 19° to 38°. The average of 9 dip 

measurements made in or near the warehouse area is approximately 

N. 26° W. The strike of the beds ranges from N. 5° E. to N. 65° E. 

and the average strike is N. 43° E.

ALLUVIAL DEPOSITS

Throughout most of Olmsted Air Force Base, the Gettysburg shale 

is covered by alluvial terrace deposits of Quaternary age. The lowest 

terrace deposit, the top of which is at an altitude of 300 feet above 

mean sea level and on which the main part of the base is situated, 

consists of gravel and sand approximately 30 feet thick. Alluvium of 

the higher terraces consists of thin, discontinuous deposits as much as 

20 feet thick. In general, however, the alluvium of the higher terraces is less than 10 feet thick.

The alluvium is believed not to be a significant aquifer at the Air 

Force Base, but it is rather permeable and rainfall infiltrates rapidly. 

Thus it is a major source of recharge to the Gettysburg shale.

GROUND-WATER HYDROLOGY

PRINCIPLES

Ground water may occur under either water-table or artesian conditions. Where the ground water is not confined, the upper surface 

of the zone of saturation is called the "water table." Where ground 

water is confined under hydrostatic pressure by relatively impermeable 

rocks, the water occurs under artesian conditions. When an artesian 

aquifer is penetrated by a well, the water will rise in the well above 

the bottom of the confining bed to a level called the "piezometric 

surface."
GROUND-WATER RESOURCES, OLMSTED AIR FORCE BASE H-9

Kecharge to a water-table aquifer comes from local precipitation or 

streamflow that infiltrates downward to the zone of saturation. Kecharge to artesian aquifers comes from precipitation or streamflow 

in the area where the aquifer is at or near the surface and is under 

water-table conditions.

On Olmsted Air Force Base, ground water occurs in the Gettysburg 

shale under artesian conditions. However, where a bed in the Gettysburg shale crops out at the surface, or beneath the alluvium, the water 

in this bed occurs under water-table conditions. The primary source 

of recharge to the artesian aquifer in the Air Force Base is precipitation percolating through the alluvium within and adjacent to the 

base.

Various terms are used to describe the hydraulic properties of an 

aquifer. The field coefficient of permeability is defined as the rate of 

flow, in gallons per day, through a cross-sectional area of 1 square foot 

under a unit hydraulic gradient and at the prevailing temperature 

of the water. The coefficient of transmissibility is defined as the field 

coefficient of permeability times the thickness of the aquifer, in feet. 

The coefficient of storage of an aquifer is the volume of water it releases from or takes into storage per unit surface area of the aquifer 

per unit change in the component of head normal to that surface. 

The specific capacity of a well is defined as the yield of the well in 

gallons per minute per foot of drawdown of water level in the well. 

Specific capacity is related directly to the transmissibility of the 

aquifer at discharge rates that are low enough to allow water to enter 

the well by laminar flow.

When a well is pumped, the piezometric surface or the water table 

is drawn down to form a "cone of depression." As pumping proceeds, 

the cone continues to deepen and broaden until one of the following 

conditions is realized: (a) recharge to the aquifer is increased in an 

amount equal to the pumping rate; (b) natural discharge from the 

aquifer is decreased in an amount equal to the pumping rate; or (c) 

the sum of the increased recharge and decreased natural discharge is 

equal to the pumping rate.

Figure 4 shows a theoretical plot of drawdown against time in a 

well pumping from a homogeneous, isotropic aquifer of infinite areal 

extent and uniform thickness. Other assumptions made in constructing the theoretical curve are: (a) the discharge well has an 

infinitesimal diameter and completely penetrates the aquifer; (b) no 

recharge occurs; (c) the water taken from storage in the aquifer is 

discharged instantaneously with the decline in head; and (d) the 

coefficient of transmissibility is constant at all places and all times. 

A plot of recovery against time should coincide with a plot of draw-
H-10 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

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GROUND-WATER RESOURCES, OLMSTED AIR FORCE BASE H-ll

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H-12 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

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GROUND-WATER RESOURCES, OLMSTED AIR FORCE BASE H-13

down against time. Any deviation from the above criteria will cause 

a plotted curve to differ from the theoretical curve. For example, 

figure 5 shows a drawdown curve whose slope decreases abruptly from 

that of the theoretical curve at point A, indicating that expansion of 

the cone of depression has induced recharge to the aquifer from some 

outside source.

Figure 6 shows a drawdown curve whose slope increases abruptly 

from that of the theoretical curve at point A, indicating that the cone 

of depression has expanded to an impermeable boundary that is, 

a boundary formed by a formation that yields less water than the 

major aquifer. An impermeable-boundary condition may appear, for 

example, when the cone of depression reaches the end of the aquifer 

and lateral expansion of the cone is stopped or retarded. An impermeable-boundary condition may also indicate a marked decrease 

in the permeability of the aquifer due to a change in the lithologic 

character of the aquifer at some distance from the well.

WAREHOUSE AREA

Rocks underlying the warehouse area do not yield large supplies 

of ground water. Pumping rates from existing wells in the area range 

from 66 gpm (gallons per minute) from well Da-79 to 85 gpm from 

wells Da-94 and Da-96. Eeported specific capacities ranged from 

0.33 in well Da-77 to 2.3 in one of the Gulf Oil Co. service-station wells 

(Da-94, 95, or 96). The measured specific capacity of well Da-78 

is 0.42 and the coefficient of transmissibility of the aquifer tapped by 

well Da-78 is about 1,250 gpd (gallons per day) per foot.

A pumping test was made on well Da-78 with a submersible pump. 

The pump was set at a depth of 135 feet and was pumped at a constant 

rate of 25 gpm. Water levels during the test were measured in wells 

Da-77, 78, and 79. (See fig. 2.) No drawdown occurred in wells 

Da-77 and '79 because these wells penetrate rocks stratigraphically 

lower than those penetrated in the pumped well. (See fig. 7.) The 

lack of drawdown in the two observation wells indicates that there is 

little or no leakage between aquifers. Water levels in well Da-77 

fluctuated over a range of half a foot during the test, but the fluctuations appear to be related to pumping of Gulf Oil Co. well Da-95 

because the entire stratigraphic section penetrated in well Da-95 is 

penetrated also in well Da-77.

Figures 8 and 9 show drawdown and recovery, respectively, of 

the pumped well (Da-78) plotted against time. The data yield 

curves which deviate from the theoretical curve (see fig. 4) at two 

points. Point A on the recovery curve (fig. 9) shows that the effect

602547 61 3
H-14 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

Da-79 Da-77 Da-95

200 100 0 200 FEET

HORIZONTAL AND VERTICAL SCALE

FIGURE 7. Cross section showing relation of strata penetrated by wells in warehouse

area, Olmsted Air Force Base. 

a. Strata penetrated only by Da-78. 

6. Strata penetrated only by Da-77 and 79. 

c. Strata penetrated only by Da-77, 79, and 95. 

d. Strata penetrated only by Da-77 and 95. 

e. Strata penetrated only by Da-77. 

/. Strata not penetrated.

of an impermeable boundary appeared 5 minutes after pumping 

stopped. Point B on figures 8 and 9 shows the effect of another 

impermeable boundary. The effect of this boundary, best shown on 

the drawdown curve (fig. 8), occurred 500 minutes after pumping 

began.

One of the impermeable boundaries, the more distant one, is believed to be at the place where the water-bearing strata come to an 

end at their outcrop. The other impermeable boundary is believed 

to represent a place at some distance from the well where the aquifer 

becomes thinner.

MAIN BASE

Wells in the main part of Olmsted Air Force Base generally yield 

large supplies of water. Pumping rates range from 130 gpm to 758 

gpm. (See table 1.) The total consumption of ground water is about 

1 mgd (million gallons per day).
GROUND-WATER RESOURCES, OLMSTED AIR FORCE BASE H-15

oq ID in *t 

c> d ci d d 9

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H-16 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

o oo 10 in

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GROUND-WATER RESOURCES, OLMSTED AIR FORCE BASE H-17

Wells on the main base can be classified in three groups that occupy 

three different areas: (a) the eastern area, comprising wells Da-80, 

81, 82, 83, and 84 (AFB-1, 2, 3, 4, and 5); (b) the central area, comprising wells Da-87, 89, and 92 (AFB-8, 10, and 13) ; and (c) the 

western area, comprising wells Da-85, 88, 90, 91, and 93 (AFB-6, 9, 

11, 12, and 14).

All wells in the eastern area (Da-80 to 84) were drilled in 1941 

except Da-84 which was drilled earlier. Original pump settings were 

140 feet below the land surface. However, after a time it was necessary to lower the pump settings to 200 feet in Da-80 (AFB-1), to 

190 feet in Da-81 (AFB-2), and to 250 feet in Da-82 (AFB-3). It 

was also necessary to deepen Da-80 an additional 179 feet to a depth 

of 629 feet. Apparently the drawdown was greater than was anticipated when the wells were first drilled.

TABLE 1. Hydrologic characteristics of wells on the Olmsted Air Force Base

[Specific capacity: r, reported; m, measured]

Well No. Depth 

(feet)

Pumping 

rate (gpm)

Specific 

capacity 

(gpm per ft 

drawdown)

T

(gpd per ft)

fir

Eastern area

Da-80 (AFB-1K 

81 (AFB-2). 

82 (AFB-3). _

83 (AFB-4). 

84 (AFB-5). 

629

450

450

459

776

260

150

185

185

235

1.9*

2.3">

.93'

.80*

I

1 25,000

1

28X10-*

Central area

Da-87 (AFB-8)- 

89 (AFB-10). 

92 (AFB-13) 

452

450

800

130

750

485

2

Qr

J

I <12,000 <12X10-»

Western area

Da-85 (AFB-6)_ 

88 (AFB-9)- 

90 (AFB-11) 

91 (AFB-12). 

93 (AFB-14) 

500

451

600

600

800

330

265

660

640

758

2.5'

1.4*

15«>

18'

4.6'

 <55,000 <10X1<H

Warehouse area

Da-77 

78 _ --- 

79 

94__ . 

95 

96 

700

300

300 66

85

70

85

.33'

.42m

2". 3"' ,<a(jO

Pumping rates of wells in the eastern area range from 150 to 260 

gpm and the specific capacities of the wells range from 0.80 to 2.3 

gpm per foot of drawdown (table 1). The average transmissibility
H-48 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

of aquifers in this area, as determined from drawdown data for wells 

Da-80 and Da-83, is about 25,000 gpd per foot. These wells were 

used for the observations because it is believed that they have greater 

hydraulic connection with the pumped well than does well Da-82.

Da-83 Da-81 Da-80 Da-82

 . Alluvium -v-'v. .'. . '. : :

200 100 0 200 FEET

HORIZONTAL AND VERTICAL SCALE

FIGURE 10. Cross section showing relation of strata penetrated by wells in eastern part

of Olmsted Air Force Base.

a. Strata penetrated only by Da-83.

6. Strata penetratedi only by Da-81 and 83.

c. Strata penetrated only by Da-80, 81, and 83.

d. Strata penetrated only by Da-80, 81, and 82.

e. Strata penetrated only by Da-80 and 82.

/. Strata penetrated only by Da-80.

g. Strata not penetrated.

(See fig. 10.) The storage coefficient of the aquifer is 28xlO~5, a figure 

typical of artesian aquifers.

One pumping test was made in the eastern area. Da-81 (AFB-2) 

was pumped at 200 gpm for 859 minutes, and wells Da-80, 82, and 

83 (AFB-1, 3 and 4) were used as observation wells. Water levels 

in the observation wells declined during the pumping test, indicating 

hydraulic connection among the wells. Maximum drawdowns were 

as follows: Da-81 (AFB-2), 90 feet; Da-80 (AFB-1), 5.6 feet; 

Da-82 (AFB-3), 0.6 foot; Da-83 (AFB-4), 6.5 feet. Wells Da-80 

and 83 are approximately 325 feet from the pumped well, and Da-82 

is 630 feet from the pumped well. Figure 10 shows the relation between strata penetrated by these four wells.
8

6 

5 

4

3

2

1

0.8

0.6 

0.5 

0.4

0.3 

0.2

0.1 

0.08

0.06 

0.05 

0.04

0.03 

0.02

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1 0.2 0.3 .0.4 0.6 0.8 1 2 3 4 5 6 8 10 20 30 .40 60 100 

TIME, /, IN MINUTES AFTER PUMPING C

FIGURE 11. Logarithmic graph of drawdown in well Da-80. Pumping test, drawdow

Da-80; location, main base (eastern area) ; discharging well Da-81; observation w
H-20 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

 £ i

O d) as

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0.6 

0.5 

0.4

0.3 

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0.06 

0.05 

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0.03 

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2 3 4 5 6 8 10 20 30 40 60 100 200 300 

TIME, t, IN MINUTES AFTER PUMPING BEG

FIGURE 13. Logarithmic graph of drawdown in well Da-83. Pump

drawdown of observation well Da-83; location, main base (eas

observation wells, Da-80, 82, and 83; date of test, Feb. 2, 1959.
H-22 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

Figures 11, 12, and 13 show drawdown curves of observation wells 

Da-80, 82, and 83. At the point on each curve the line steepened in 

slope, indicating an impermeable boundary. The effect of the impermeable boundary appeared in wells Da-80 and Da-83 about 200 

minutes after pumping started. It appeared in well Da-82 after 

400 minutes of pumping. The exact nature of the impermeable boundary is not known.

Pumping rates of wells in the central area range from 130 to 750 

gpm. The specific capacity of well Da-89 (AFB-10) is reported to 

be 2.3 gpm per foot of drawdown. (See table 1.)

One pumping test was made in this area. Well Da-92 (AFB-13) 

was pumped at 575 gpm for 195 minutes and well Da-87 (AFB-8) 

was used as an observation well. The water level in the observation 

well declined 5.5 feet, during the test, indicating hydraulic connection 

with the pumped well. The water-level drawdown in the pumped well 

was more than 90 feet. The coefficients of transmissibility and storage 

obtained from figure 14 are believed to be greater than the correct 

values, because well Da-87 taps only the upper part of the stratigraphic section penetrated in well Da-92, and well Da-87 probably 

does not tap the strata that yield much of the water to well Da-92. 

Figure 14 shows the effects of a recharge boundary at point A. The 

effect became apparent 15 minutes after pumping started. The recharge-boundary effect is probably caused by induced recharge from 

the Susquehanna River, which is 2,200 feet from well Da-87. It is 

not known definitely whether the river is recharging the aquifer directly or recharging the overlying alluvium, which in turn recharges 

the aquifer. In either case, however, the pumping of well Da-92 results in diversion of river water to the artesian aquifer at the Air 

Force Base.

Wells in the western area are pumped at rates ranging from 265 

gpm to 758 gpm, and the specific capacities of wells range from a reported 1.4 gpm per foot of drawdown to a reported 18 gpm per foot 

of drawdown. (See table 1.) The coefficient of transmissibility of 

the aquifer penetrated by well Da-91 (AFB-12) was calculated to be 

55,000 gpd per foot, but this figure may be too high. The storage 

coefficient is calculated to be 10 x 10~5 .

A test was made in this area by pumping well Da-90 (AFB-11) at 

700 gpm for 315 minutes and observing the drawdown of water level 

in wells Da-88 (AFB-9) and Da-91 (AFB-12). The water levels in 

the observation wells declined during the test, indicating hydraulic 

connection with the pumped well. The maximum drawdowns observed were 45 feet in well Da-90, 0.7 foot in well Da-88, and 4.6 feet 

in well Da-91. As shown in figure 15, the upper strata penetrated by 

the pumped well are also penetrated by well Da-91, whereas only the
8

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5 

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3 

2

1 

0.8

!H 0.6 

£ 0.5 

? 0.4

>- 0.3 

cc

SJ

0 0.2

UJ

cc

0.1 

0.08

0.06 

0.05 

0.04 

0.03

0.02 

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r °

0.2 0.3 0.4 0.7 1 2345 10 20 30 

TIME. t. IN MINUTES AFTER PUMPING C

FIGURE 14. Logarithmic graph of recovery in well Da-87. Pumping te

of observation well Da-87; location, main base (central area) ; 

well, Da-87; date of test, Jan. 30, 1959.
H-24 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES 

Da-91 Da-90 Da-88

400 200 400 FEET 

_I

HORIZONTAL AND VERTICAL SCALE

FIGURE 15. Cross section showing relation of strata penetrated by 

wells in western part of Olmsted Air Force Base. 

a. Strata penetrated only by Da-91. 

6. Strata penetrated only by Da-90 and 91. 

c. Strata penetrated only by Da-88 and 90. 

d. Strata penetrated only by Da-88. 

e. Strata not penetrated.

lower strata are penetrated in well Da-88. Because much greater 

drawdown occurred at well Da-91, it is probable that the important 

water-bearing strata in well Da-90 occur in the upper half of the well. 

Further evidence of this probability will be discussed subsequentlv. 

Figures 16,17, and 18 show recovery curves for wells Da-88, 90, and 

91. Point A on the curves shows the effect of a recharge boundary, 

which occurred half a minute after pumping ceased in well Da-90, 

7 minutes after pumping ceased in well Da-91, and 60 minutes after 

pumping ceased in well Da-88. The effect of the recharge boundary 

on water levels occurred very early in the test, which indicates that the 

recharging source is nearby. The ultimate source is clearly the Susquehanna River. The recharging source is not necessarily the river 

proper but may be the alluvium, which in turn is recharged by river 

water. The wide difference between arrival times of the effects of 

the recharge boundary in the observation wells indicates that Da-88 

is not as closely connected hydrologically to the pumped well as is 

Da-91. This is further evidence that the water-bearing strata are 

largely in the upper half of the pumped well.
8

6 

5 

4 

3

2

1 

0.8

0.6 

0.5 

0.4

0.3 

0.2

0.1 

0.08

0.06 

0.05 

0.04

0.03 

0.02

0.01

/

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Mat

~1

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©

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1* 

X^

/

X

r^

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(<*'

n<

,*

rf

<0fT°

^

30

^^

2 3 4 5 6 8 10 20 30 40 60 100 200 300 

TIME, t, IN MINUTES AFTER PUMPING CE

FIGDEB 16. Logarithmic graph of recovery in well Da-88. Pumping 

of observation well Da-88; location, main base (western area) 

wells, Da-88 and 91; date of test, Jan. 26, 1959.
500

400

300

200

100

tu

UJ 

" SO

z ,.n

£ 30

Ul 

§Ort

Ul 

<£

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TIME, t, IN MINUTES AFTER PUMPING C

FIGURE 17. Logarithmic graph of recovery in well Da-90. Pumping t

lof discharge well Da-90 ; location, main base (western area) ; disc

Da-88 and 91; date of test, Jan. 26, 1959. It is not possible 

these data.
5

4

3 

2

1

LU

"- 0.5 

Z 0.4

£ 0.3

LU

8 0.2

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0.1

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0.1 0.2 0.3 0.4 0.7 1 2345 10 20 30 

TIME, t, IN MINUTES AFTER PUMPING CEAS

FIGURE 18. Logarithmic graph of recovery in well Da-91. Pumping te

of observation well Da-91; location, main base (western area) ; disch

Da-88 and 91; date of test, Jan. 26, 1959.
H-28 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

GEOCHEMISTRY

Ground water in the main part of Olmsted Air Force Base is high 

in calcium and low in sodium and potassium. The chemical composition of the water differs from well to well, and in any given well it 

varies with time. Hardness as CaCO3 ranges from 137 to 826 ppm 

(parts per million). Dissolved solids range from 200 to 1,340 ppm. 

Analyses of water from wells Da-80 to Da-93 (AFB 1-14) on the 

main base are given in table 2.

TABLE 2. Chemical analyses of water from

[In parts per million

USGS 

Well No.

Da-80 .

SO. 

SOSO 

Da-81 _ 

81 

81 

81 

Da-82 

82 

82 

82. 

Da-83 

83 

83 

83 -

Da-84....

84 

84 

84 

Da-85 

85 

85 

85 

Da-87 __

87 

87 

87 

Da-88 

88 

88 

Da-89 

89 

89....

Da-90 

90. 

Da-91 

91

Da-92 

09

Da-93- 

93. 

Owner and owner's 

well No.

Olmsted Air Force Base: 

Welll.-. __ ___________

 do..... .

 do... 

... -do.. 

Well 2- . __ ... _ ...

 -do- ................

... ..do- 

 -do- ........

Well 3. . . ...

 ..do- ______________

.....do- 

_. do- ................

Well 4 

.....do-.. . . ______

 -do. __ ... _ ..___

Well5....____________ .

 .do. _. 

_.__ .do- ___ ._ _..

 .do. , __ 

Well 6- ______ ... .

 do- . 

 do- __ _ ________

 .do. 

Well 8 _ _ ________

 .do. ________________

 .do . 

.. do. ________________

Well 9 ___

 do_ ________________

 .do. __ . 

Well 10...... _________ ...

 .do.... _________ ...

 .do.. ......... _.

Well 11_ ______________

 .do__ .... _____ ....

WeU 12_ _______ _ 

 .do 

Well 13__ . .....

 .do. _. ,__ _____

Well 14 __ .. _ . _ . _

- do 

Date of 

collection

6-5-53

5-7-56

6-11-57

7 9^_Rft

6-5-53

5-7-56

6-11-57

7-22-58

6-5-53

5-7-56

6-11-57

7 27 58

6-5-53

6-11-57

7-23-58

6-5-53

5-10-56

6-18-57

7 9*v_P.ft

6-5-53

5-9-56

6-12-57

7 9*v_e.Q

6-5-53

5-11-56

6-20-57

7 9/1 W

5-9-56

6-12 57

7 99 P»ft

5-11-56

6-20-57

7-24-58

7 09 eo

7-23-58

6-13-57

7-25-58

Silica 

(SiOi)

78

26

31

9O

87

26

30

26

81

28

30

26

94

23

28

94.

74

28

31

9O

98

91

18

15

95

18

9°.

91

17

99

20

OK

28

f)K

24

21

20

26

26

24

99

Iron

(Fe)

0.01

.09

.07

no

.08

.03

.05

no

.04

.00

.08

AQ

.04

.02

.10

.07

.05

.03

.07

.26

.08

AA

.08

.22

.59

2.4

5 9

1.6

.06

.15

AQ

.20

oo

19

.07

.31

1 9

1.4

.38

.16

Calcium 

(Ca)

103

85

85

82

75

75

71

76

86

92

69

on

90

84

56

69

270

176

79

154

68

61

71

118

66

62

58

53

81

98

154

45

54

53

71

86

71

66

40

44

101

162

Magnesium 

(Mg)

18

32

16

18

16

21

15

17

9.7

15

7.5

7 9

24

25

15

17

37

45

11

18

22

14

4.0

17

10

14

11

12

18

22

31

9.9

8.5

11

14

21

11

10

9 A

15

27

Sodium 

(Na)

14

16

l

15

10 12

19

10

17

19

8.5

11 15

1]

4.8

47 il

i

27

H

i

16

10

18

19

7.8

i

i

23

ij

17

5.3

l

10

15

9 7

19

33

Potassium 

(K)

1.5

4

14

1.5

.5

9

1.3

.1

.0

1.6

.1

0

1.9

.4

14

1.5

.7

25

1.6

3

7

.2

L5

.6

.8

.0

13

----

.8

........

........

i Sodium and potassium, calculated as sodium.
GROUND-WATER RESOURCES, OLMSTED AIR FORCE BASE H-29

Field determinations of hardness and specific conductance of 

ground water from the warehouse area are available for comparison 

with data from the main base. The hardness as CaCO3 and specific 

conductance of water from well Da-78 are 120 ppm and 280 micromhos 

per cm. A specific conductance of 280 micromhos per cm is approximately equivalent to 190 ppm of dissolved solids. Water samples 

from wells Da-94, 95, and 96 (Pennsylvania Turnpike, Gulf Oil Co. 

service station), adjacent to the warehouse area, had a hardness of

wells on Olmstead Air Force Base

except as indicated]

Bicarbonate 

(HC03)

188

188

177

188

188

189

180

182

192

195

173

185

172

166

144

154

140

164

177

166

172

148

148

115

196

164

180

172

204

210

218

146

163

170

189

181

158

126

118

128

196

201

Carbonate 

(C03)

0

0

0

0

0

0

0

0

0

0

0

0

0

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Sulfate 

(800

165

162

125

120

89

88

80

95

83

101

43

63

177

156

80

103

708

434

104

337

129

73

101

274

50

75

45

41

115

172

345

26

24

22

75

135

95

111

31

46

156

396

Chloride 

(Cl)

16

14

12

12

10

11

9.8

9.0

13

14

8.8

10

9

6.7

5.8

6.2

36

16

7.7

8.8

8.5

9.0

8.4

10

10

7.3

5.6

5.5

7.0

7.5

9.5

7.0

11

11

9.8

12

9.2

12

4.6

4.8

5.8

6.5

Flouride (F)

0.0

.0

.1

.0

.2

.0

.1

.0

.0

.0.1

.0

.0

.0.1.1

.1.1.1

.3

.0

.1

.1

.1

.0.1.1

.1

.0.1.1

.0.1.1

.1

.0

.0

.0

.1

.0

.1.1

Nitrate 

(N03)

16

19

19

18

19

21

18

19

22

27

28

24

16

15

16

13

31

22

20

20

14

12

11

6.5

5.2

9.4

9.1

O. Q 1 1

7.5

7.7

11

19

15

13

11

14

11

5.7

17

20

3.5

1.0

Dissolved 

solids

510

450

398

394

410

351

344

349

410

395

290

333

520

413

296

372

1,340

820

347

676

430

278

314

554

350

297

266

268

368

462

727

216

237

240

320

468

318

317

200

224

425

792

Hardness 

as 

CaCO3

331

344

278

279

253

274

239

260

254

291

203

232

323

312

201

242

826

624

242

458

260

210

194

365

206

213

190

182

276

335

512

153

170

177

235

301

222

218

137

155

314

516

Noncarbonate 

hardness

177

190

133

125

99

117

91

111

97

131

61

.81

182

176

83

116

711

490

106

322

119

88

72

271

45

78

42

41

109

163

333

33

36

38

80

153

93

115

41

50

153

351

Specific 

conductance 

(micromhos at 

25° C.

669

675

578

577

526

529

495

520

539

586

429

495

654

599

437

497

1,550

1,170

510

901

560

430

475

720

431

431

403

380

556

652

980

317

370

378

477

595

476

463

295

338

604

1,000

PH

7.8

7.9

7.0

7.2

7.9

8.2

7.3

7.6

7.5

7.7

7.2

7.3

7.9

8.3

7.2

6.6

7.9

8.0

7.3

7.6

7.9

7.9

7.7

7.2

7.6

8.1

7.8

7.8

8.0

7.1

8.0

7.9

6.9

7.5

7.2

7.6

6.8

7.7

7.3

7.4

7.8

8.0
H-30 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

137 ppm and a specific conductance of 360 micromhos per cm (approximately 240 ppm of dissolved solids). Hence, judging from 

these data, ground water in the warehouse area is much softer and 

contains less dissolved solids than water on the main base. (See 

table 2.)

Fluid-resistivity logs revealed a highly mineralized water at depths 

below 300 feet in wells Da-77 and Da-79. Lack of sufficient data 

prevents a satisfactory explanation of this mineralization, but because 

the water occurs at the same depth in two wells which are approximately along the strike of the strata, it is believed that this water may 

be confined to a particular bed or group of beds.

Tests for specific conductance and hardness were made on samples 

of ground water taken during pumping tests. Hardness as CaCO3 

and specific conductance increased during the early stages of three 

of the tests but remained constant as pumping continued. Table 3 

shows the changes that occurred during pumping. The changes in 

chemical composition of the water that took place during the early 

stages of pumping may have been caused by the changes in the 

amounts of water supplied by individual aquifers tapped by the 

pumped well, or they may have been caused by movement of more 

highly mineralized water from downdip in one or more aquifers.

Ground water in the main base falls into three geochemical groups 

that coincide with the three distinct areas on the Air Force Base. 

Each of these areas has a different pumping history. Table 4 summarizes certain characteristics of water in each group.

TABLE 3. Change of hardness and specific conductance during pumping of wells

Well No.

Da-81 (AFB-2)__.______ _._

Da-92 (AFB-13) _______ .__

Da-90 (AFB-11). __________

Time (minutes)

38

105 

210 

316 

480 

780

5

75 

130 

180

30

60

70

135

150

215

300

Hardness as CaCOa 

(ppm)

154

205 

205 

222 

222 

222

171

205 

222 

222

290

290

308

308

Specific conductance (micromhos 

per cm at 25° C.)

425

475 

480 

500 

500 

500

285

450 

465 

475

675

675

675
GROUND-WATER RESOURCES, OtMSTED AIR FORCE BASE H-31

TABLE 4. Comparison of the chemical character of ground water in the three

areas of the main base

Geochemical group

Eastern area

Wells Da-80, 81, 82,

83, 84 (AFB 1-5).

Central area

Wells Da-87, 89, 92

(AFB 8, 10, 13).

Western area

Wells Da-85, 88, 90,

91,93 (AFB 6, 9, 11,

12, 14).

Year

f 1953

j 1956

1 1957

I 1958

f 1953

I 1956

I 1957

[ 1958

f 1956

1957

1 1958

Average

sulfate

content

(ppm)

244

188

86

144

50

51

33

36

94

120

252

Percentage

equivalents per

million of

804+Cl+NOs

59

57

46

52

31

36

31

32

45

49

65

Hardness

as CaCOj

397

369

233

294

206

183

166

171

243

260

382

Specific

conductance (mlcromhos

at 25° C.)

788

712

490

598

431

374

356

365

493

537

752

One geochemical group coincides with the eastern area, which includes wells Da-80, 81, 82, 83, and 84 (AFB-1, 2, 3, 4, and 5). This 

area has been yielding ground water since 1941. The water is moderately to very hard and is fairly high in sulfate and dissolved solids. 

Sulfate content, hardness, and specific conductance decreased from 

1953 to 1958.

Another geochemical group coincides with the central area, which 

includes wells Da-87, 89, and 92 (AFB-8, 10, 13). Water from this 

area is relatively low in sulfate content, contains less dissolved solids, 

and, though hard, is much softer than water in the eastern area. 

Much less water has been pumped from this area than has been 

pumped from the eastern area, and little or no change in the chemical 

character of the ground water took place between 1956 and 1958. 

Wells Da-87 and Da-92 have been contaminated by petroleum products since 1957. The contamination was caused by leakage of petroleum products (used in Air Force Bace operations) through the 

alluvium into the aquifer.

The third geochemical group coincides with the western area which 

includes wells Da-85, 88, 90, 91, and 93 (AFB-6, 9, 11, 12, and 14). 

In general, this area except for Da-85 has been yielding water since 

1953. The water here has been characterized by a rapid change in 

chemical character from moderate sulfate content (94 ppm in 1956) 

to high sulfate content (252 ppm in 1958). Specific conductance and 

hardness as CaCO3 also have risen sharply.

Figure 19 shows the percentages of equivalents per million of important constituents or groups of constituents in the various types of
H-32 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

CATIONS ANIONS 

PERCENTAGE EQUIVALENTS PER MILLION

FIGURE 19. Trilinear diagram showing chemical character of ground water at Olmsted

Air Force Base.

1. Eastern area, wells Da-80 to Da-84.

2. Central area, wells Da-87, 89, and 92.

3. Western area, wells Da-85, 88, 90, 91, and 93 ; 1956.

4. Western area, wells Da-85, 88, 90, 91, and 93 ; 1957.

5. Western area, wells Da-85, 88, 90, 91, and 93 ; 1958.

6. Susquehanna River, east channel at Harrisburg.

water at Olmsted Air Force Base. Sulfate and chloride are plotted 

against carbonate and bicarbonate on one axis and calcium and magnesum are plotted against sodium and potassium on another axis. The 

graph shows the general chemical character of ground water in the 

three geochemical groups. The graph shows also the progressive 

change in water character toward the calcium sulfate type in the 

western area.

Ground water in the main part of Olmsted Air Force Base appears 

to be a mixture of two chemical types: (a) the calcium bicarbonate 

type, as exemplified by water from the central area and by the early 

analyses of water from the western area, and (b) the calcium sulfate
GROUND-WATER RESOURCES, OLMSTED AIR FORCE BASE H-33

type, as exemplified by water from the eastern area and by the 1958 

analyses from the western area. Water from a newly pumped or 

little-pumped area falls within the calcium bicarbonate type and is 

low in dissolved solids. As heavy pumping continues, the water 

changes to the calcium sulfate type and becomes harder, and the 

dissolved solids increase. The first type probably represents water 

that is being recharged by precipitation at the outcrop area under the 

alluvium. The second type represents water that has been in storage 

in the aquifer, probably downdip from the pumped well.

CONCLUSIONS

The warehouse area does not appear to be a potential source for 

large supplies of ground water. The coefficient of transmissibility of 

the aquifers tested is very low, and no aquifers of higher potential 

appear to be present. Specific capacities of the existing wells also 

are very low, and the presence of nearby impermeable boundaries 

means that water levels will continue to decline rapidly in the area if 

large withdrawals are made. In addition, the electric logs of wells 

Da-77 and 78 revealed the presence of some highly mineralized water 

in the area.

However, if it is absolutely necessary for a ground-water supply 

to be developed in the warehouse area, the following procedures should 

afford the greatest possibility of success. It is probable that 10 to 

15 wells would be needed to obtain a total yield of TOO gpm. As the 

specific capacities of the wells are low, the wells should be located sc 

as to penetrate the greatest possible section of potential water-bearing 

strata. Wells should be spaced sufficiently far apart (stratigraphically) to insure that no two nearby wells will penetrate the same 

strata; this will afford minimum interference between wells. Wells 

drilled along a line perpendicular to the strike of the strata (in the 

direction of dip) will permit minimum spacing between wells. Wells 

drilled according to some other plan should be spaced farther apart. 

The average dip of the strata in the area is 26° to the northwest, and 

the tangent of this angle is approximately 0.5; therefore, the lowest 

strata in a 300-foot well (for example) will crop out 600 feet to the 

southeast of the well. Wells drilled 300 feet deep should, therefore, 

be spaced at least 600 feet apart along a line perpendicular to the 

strike.

If any exceptionally good aquifer is penetrated, it may be advisable 

to drill additional wells along the strike of the strata in order to tap 

the same aquifer, but care should be taken to space the wells far enough 

apart to minimize interference between wells.
H-34 CONTRIBUTIONS TO THE GEOLOGY OF THE UNITED STATES

Available data are insufficient to determine optimum depths of wells. 

However, the range in depth of wells probably should be from 300 to 

600 feet.

Large supplies of ground water are available on the main base. 

The eastern area contains greater supplies of water than the warehouse area, but extensive further development in the vicinity of the 

existing wells would cause excessive interference because a relatively 

impermeable boundary exists in this area.

The central and western areas are capable of yielding large supplies 

of water. A recharge boundary representing induced recharge from 

the Susquehanna River exists in both these areas. The central area, 

however, has yielded ground water of poor quality due largely to 

surface contamination.

The western area appears to offer the greatest potentiality for 

future ground-water development. The specific capacities of wells 

and the transmissibilities of the aquifers in this area are the highest 

on the entire base. The existing wells in the western area are capable 

of yielding sufficient additional water to supply the demands of the 

warehouse area. Wells in this area, especially wells Da-90, 91, and 93 

(AFB-11,12, and 14), can be pumped for considerably longer periods 

of time each day than they are now being pumped, without danger 

of excessive lowering of water levels.

A supplemental supply of water may be required in case of breakdowns or other emergencies. To provide for such an occurrence, one 

new well in the western area may be needed.

REFERENCES CITED

Hall, G. M., 1934, Ground water in southeastern Pennsylvania: Pennsylvania 

Geol. Survey, 4th ser., Bull. W-2, 255 p.

Peltier, L. C., 1949, Pleistocene terraces of the Susquehanna River, Pennsylvania: Pennsylvania Geol. Survey, 4th ser., Bull. G-23, 158 p.

Stose, G. W., and Jonas, A. L, 1933, Geology and mineral resources of the Middletown quadrangle, Pennsylvania: U.S. Geol. Survey Bull. 840, 86 p.

U.S. GOVERNMENT PRINTING OFFICE: 1981