Ground-Water Flow Directions and 

Estimation of Aquifer Hydraulic Properties 

in the Lower Great Miami River Buried 

Valley Aquifer System, Hamilton Area, Ohio

By Rodney A. Sheets and Karen E. Bossenbroek

With a section on

Scientific Investigations Report 2005-5013

U.S. Department of the Interior

U.S. Geological Survey

In cooperation with the City of Hamilton and the Hamilton to New Baltimore 

Ground Water Consortium
U.S. Department of the Interior

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

U.S. Geological Survey, Reston, Virginia: 2005

Revised and reprinted: 20xx

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Title of book/ Author List

p. cm. –(U.S. Geological Survey professional paper ; 0000)

Includes bibliographic references.

1. Subject heading. 2. Subject heading. 3. Subject heading. I. Main entries. 

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iii

Contents

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

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

Purpose and Scope ................................................................................. 3

Description of Study Area ........................................................................ 3

Previous Work ....................................................................................... 3

Methods ................................................................................................... 4

Ground-Water System .................................................................................... 6

Geologic Setting and Lithology .................................................................. 6

Recharge ............................................................................................. 8

Ground-Water Flow Directions ........................................................................ 9

Estimation of Aquifer Hydraulic Properties ............................................................ 14

Summary and Conclusions .............................................................................. 19

Acknowledgments ....................................................................................... 20

References Cited .......................................................................................... 20

Appendix 1. Diagrams showing lithology, grain-size characteristics, screened intervals,

 and estimated hydraulic conductivity in borings at Hamilton North Well Field ......... 23

Appendix 2. Water-level elevations in piezometers in the Great Miami River and in

 production wells near the Hamilton North Well Field ....................................... 29

Figures

 1. Map showing location of the Hamilton North and South Well Fields and glacialaquifer yields in northern Butler County, Ohio ............................................. 2 

 2. Map showing location of wells and piezometers used to determine aquifer 

characterics .................................................................................... 4

 3. Stratigraphic section A-A’ through the north part of the Hamilton North Well Field 7

 4. Stratigraphic section B-B’ through Hamilton North Well Field ........................... 8

 5–6. Graphs showing water levels in monitoring wells at Hamilton North Well Field and 

in the Great Miami River, and a barograph for a weather station at Butler County 

Regional Airport:

 5. Shallow wells ................................................................................. 10

 6. Deep wells .................................................................................... 11

 7. Map showing water-level contours in Hamilton North Well Field during pumping 

and nonpumping conditions .................................................................. 12 

 8–9. Graphs showing water levels in the Great Miami River and wells along a groundwater flow path to the Great Miami River, and barograph for a weather station at 

 the Butler County Regional Airport, Ohio:

 8. Shallow wells ................................................................................. 13

 9. Deep wells .................................................................................... 14 

 10. Graphs showing drawdown measured 94 hours from start of aquifer test against 

monitoring-well distance from pumping well, used to calculate transmissivity and 

 storage coefficient for wells 1D, 4D, and 5D ............................................. 16
iv

Conversion Factors and Datums

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square foot (ft2) 929.0 square centimeter (cm2)

square foot (ft2) 0.09290 square meter (m2)

Volume

gallon (gal) 0.003785 cubic meter (m3) 

cubic foot (ft3) 0.02832 cubic meter (m3) 

Flow rate

foot per day (ft/d) 0.3048 meter per day (m/d)

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

gallon per day (gal/d) 0.003785 cubic meter per day (m3/d)

million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3/s)

inch per year (in/yr) 25.4 millimeter per year (mm/yr)

Pressure

inch of mercury at 60oF (in. Hg) 3.377 kilopascal (kPa) 

inch of mercury at 60oF (in. Hg) 70.7262 Pounds per square foot (1b/ft2)

Specific capacity

gallon per minute per foot 

 [(gal/min)/ft)]

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

Hydraulic conductivity

foot per day (ft/d) 0.3048 meter per day (m/d)

Hydraulic gradient

foot per mile (ft/mi) 0.1894 meter per kilometer (m/km)

Transmissivity*

foot squared per day (ft2/d)

foot squared per day (ft2/d)

 0.09290

 7.4805

meter squared per day (m2/d)

gallons per day per foot (gal/d/ft)

Verticle 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 or elevation, as used in this report, refers to distance above the vertical datum.

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

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

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

 11–12. Graphs showing composite drawdown for monitoring wells at Hamilton North Well 

Field and calculated type curves for selected monitoring wells:

 11. Type curves from Neuman and Witherspoon (1969) .................................... 17

 12. Type curves from Moench (1997) ......................................................... 18

Table

 1. Boring and well information for Hamilton North Well Field aquifer study ............ 5
Ground-Water Flow Directions and Estimation of Aquifer 

Hydraulic Properties in the Lower Great Miami River 

Buried Valley Aquifer System, Hamilton Area, Ohio.

By Rodney A. Sheets and Karen E. Bossenbroek

Abstract

The Great Miami River Buried Valley Aquifer System 

is one of the most productive sources of potable water in the 

Midwest, yielding as much as 3,000 gallons per minute to 

wells. Many water-supply wells tapping this aquifer system 

are purposely placed near rivers to take advantage of induced 

infiltration from the rivers. 

The City of Hamilton’s North Well Field consists of 10 

wells near the Great Miami River, all completed in the lower 

Great Miami River Buried Valley Aquifer System. A welldrilling program and a multiple-well aquifer test were done to 

investigate ground-water flow directions and to estimate aquifer hydraulic properties in the lower part of the Great Miami 

River Buried Valley Aquifer System. Descriptions of lithology 

from 10 well borings indicate varying amounts and thickness 

of clay or till, and therefore, varying levels of potential aquifer 

confinement. Borings also indicate that the aquifer properties 

can change dramatically over relatively short distances. Grainsize analyses indicate an average bulk hydraulic conductivity 

value of aquifer materials of 240 feet per day; the geometric 

mean of hydraulic conductivity values of aquifer material was 

89 feet per day. Median grain sizes of aquifer material and 

clay units were 1.3 millimeters and 0.1 millimeters, respectively. 

Water levels in the Hamilton North Well Field are 

affected by stream stage in the Great Miami River and 

barometric pressure. Bank storage in response to stream 

stage is evident. Results from a multiple-well aquifer test at 

the well field indicate, as do the lithologic descriptions, that 

the aquifer is semiconfined in some areas and unconfined in 

others. Transmissivity and storage coefficient of the semiconfined part of the aquifer were 50,000 feet squared per day and 

5x10-4, respectively. The average hydraulic conductivity (450 

feet per day) based on the aquifer test is reasonable for glacial 

outwash but is higher than calculated from grain-size analyses, 

implying a scale effect. Although the part of the lower Great 

Miami River Buried Valley Aquifer System where the Hamilton North Well Field is located is semiconfined, unconfined, 

or locally confined and not directly connected to the Great 

Miami River, the discontinuity of the clay/till layers beneath 

the river indicates that other, deeper parts of the aquifer system may be directly connected to the Great Miami River.

Introduction

Ground water in the Great Miami River Buried Valley 

Aquifer System (GMR-BVAS) has been a water source since 

the early 19th century, and domestic and industrial growth 

in the Great Miami River Valley can be directly attributed 

to plentiful ground-water resources. The GMR-BVAS is a 

highly productive sand and gravel aquifer system contained in 

a buried valley and is one of the most productive sources of 

ground water in the Midwestern United States. It is recognized 

as a Sole-Source Aquifer by the U.S. Environmental Protection Agency (2004). The buried valley was formed during 

interglacial episodes of the Pleistocene Epoch and was subsequently filled with sand and gravel outwash (Spieker, 1968). 

Laterally and vertically discontinuous clay or till layers within 

the outwash can act as barriers to downward flow (Klaer and 

Thompson, 1948). The buried valley averages 2 mi in width 

and 150–200 ft in depth; yields to wells in the GMR-BVAS 

are as high as 3,000 gal/min (fig. 1). 

The GMR-BVAS supplies drinking water to approximately 97 percent of the 1.6 million people in the Great 

Miami River basin (Debrewer and others, 2000). Previous 

studies at the public-supply wells along the Great Miami 

River (Dumouchelle, 1998; Sheets and others, 2002) have 

shown that aquifer interaction with the Great Miami River is 

an important influence on ground-water flow and transport 

in the BVAS. Induced infiltration (or bank filtration) to wells 

from rivers and streams occurs when the hydraulic head in 

the aquifer, through pumping, is artificially lowered below 

the head in the stream. Many public-supply wells are near the 

Great Miami River; therefore, induced infiltration (or bank 

filtration) at well fields along the river may impact logistical 

considerations, such as location of wells and pumping rates 

and schedules. 

The City of Hamilton, Ohio, supplies about 20 Mgal/d 

from the GMR-BVAS to residents and industry in the area surrounding the city. Currently (2004), the city operates two well 
2 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

fields, both of which are adjacent to the Great Miami River. 

The North Well Field is about 2 mi north of Hamilton, and the 

South Well Field is about 4 mi south (fig. 1). 

Many wells in the Hamilton area have been drilled closed 

to the Great Miami River to allow for induced infiltration. In 

addition, pumping of wells can increase ground-water flow 

from regional, downvalley flow (Sheets and others, 2002; 

Walton and others, 1967). The water-supply wells at the 

Hamilton North Well Field were drilled in close proximity to 

the Great Miami River, with the intent to induce infiltration; 

however, laterally discontinuous clay layers between the river 

and wells may act as barriers to induced infiltration. 

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

the City of Hamilton, Ohio, and the Hamilton to New BaltiFigure 1. Location of Hamilton North and South Well Fields and glacial-aquifer 

yields in northern Butler County, Ohio.
Introduction 3

more Ground Water Consortium, began a study to examine the 

ground-water flow system at the Hamilton North Well Field 

(fig. 1). The study was done to gather additional information 

about ground-water flow and aquifer hydraulic properties 

at the well field, which may have transfer value to similar 

areas in the BVAS. The study builds on many years of USGS 

investigations of the BVAS regarding quantity and quality of 

ground water upstream from Hamilton; moreover, it complements recent research on induced (bank) infiltration at a 

BVAS site downstream, near Cincinnati. 

Purpose and Scope 

This report describes the ground-water flow system at 

and around the Hamilton North Well Field area, especially in 

terms of stream-aquifer interactions and the effect of clay layers on ground-water flow. This report also provides estimates 

of the hydraulic properties of the lower GMR-BVAS in this 

area. All hydrologic data collected by the USGS during the 

2-year study are summarized in this report; these data include 

well logs and sieve analyses from a drilling program, water 

levels in wells and piezometers, and responses of water levels 

in wells to pumping. 

Description of Study Area

The study area is the Hamilton North Well Field, consisting of 10 production wells, in the lower GMR-BVAS just 

north of the city of Hamilton in Butler County, southwestern 

Ohio (fig. 1). The northernmost of the production wells in the 

well field is shown in figure 2. During the early 21st century, 

the production wells typically have been used during peak 

operations only, usually in the summer, as a supplement to 

water withdrawn from the Hamilton South Well Field, about 6 

mi to the south (fig. 1). Bedrock surface is 150–200 ft below 

land surface at the well field (fig. 2; Leow and others, 1998). 

Land use in the area consists primarily of agriculture 

in the uplands and an urban corridor along the Great Miami 

River. Land use is mixed agricultural and industrial near the 

Hamilton North Well Field. The occurrence and distribution 

of precipitation in the area controls both surface- and groundwater flow. Southwest Ohio’s climate is classified as humid 

temperate, and the average annual precipitation for Hamilton 

is approximately 39.5 in. (Harstine, 1991).

The region is in the Till Plains section of the Central 

Lowland Physiographic Province (Fenneman, 1938). Physiography of the lower Great Miami River Valley is flat to 

gently rolling in the uplands, with steep-sided valleys near the 

river. The topography is a result of continental glaciations and 

resulting outwash streams, which formed the buried valleys. 

Previous Work

The unconsolidated outwash in the lower GMR-BVAS 

is the main source for ground water and water supplies for 

the region. Ground-water resources and ground-water/surface-water relations in the lower Great Miami River Valley 

have been described by many authors (for example, Klaer 

and Thompson, 1948; Dove, 1961; Pruel, 1965; Walton and 

others, 1967; Spieker, 1968; Ward and others, 1987; CH2MHILL, 1992; Sheets and others, 2002). The following are brief 

descriptions of some of these studies in relation to the part of 

the GMR-BVAS underlying the City of Hamilton. 

Klaer and Thompson’s hydrologic investigation of the 

Cincinnati area (1948) included the City of Hamilton. On the 

basis of well logs in the vicinity of Hamilton, they concluded 

that continuous clay layers were absent and that the aquifer consisted of a single water-bearing formation. Sluggish 

ground-water-level responses to river levels in the area just 

north of the city were attributed to a small amount of recharge 

from the Great Miami River. However, Klaer and Thompson 

also concluded that other wells indicated rapid recharge of 

river water during high stages of the Great Miami River (1948, 

p. 56). 

 In 1968, the USGS examined the lower GMR-BVAS 

and divided the area into 11 “hydrogeologic environments” 

(Spieker, 1968). These environments are based on the nature 

and thickness of the aquifer materials, the availability of 

recharge by induced stream infiltration, and the presence or 

absence of clay confining layers. The City of Hamilton is in 

the hydrogeologic environment considered the most favorable for development of large ground-water supplies. Spieker 

(1968) described this area as containing 150 ft or more of sand 

and gravel with no retarding clay layers and close enough 

to the river to allow for induced infiltration. Spieker (1968) 

estimated transmissivity (T) of the aquifer in this area to be 

from 300,000 to 500,000 gal/d/ft (40,000 to 67,000 ft2/d). The 

estimated storage coefficient (S) is 0.2. Individual wells can 

yield 3,000 gal/min or more and have specific capacities of as 

much as 300 gal/min/ft of drawdown (Spieker, 1968). CH2MHILL (1992) summarized hydraulic properties for the lower 

GMR-BVAS; according to their report, hydraulic conductivity 

of the buried valley sediments ranges from 400 to 600 ft/d. 

Numerical modeling was used at the Chem-Dyne Superfund site, about 2 mi south of the Hamilton North Well Field 

(fig. 1), as a tool for determining corrective action at the site. 

A well-defined clay lens was reported between the site and 

the Great Miami River, about 50 ft thick and extending under 

the river (Ward and others, 1987). CH2M-HILL (1992) also 

described a zone composed of discontinuous lenses of clay, 

sand and gravel, or fine-grained sand that separates the valleyfill deposits into upper and lower layers. 
4 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

Methods

Previous studies have shown that ground-water flow is 

generally in the direction of surface-water flow (or parallel 

to the buried valley walls); but near a pumping well, flow is 

perpendicular to the main axis of the Great Miami River with 

a component of downvalley flow (Klaer and Thompson, 1948; 

CH2M-HILL, 1992; Sheets and others, 2002). With these flow 

patterns in mind, the USGS drilled 10 borings at the Hamilton 

North Well Field during October 6–20, 2002, using a 6-in. hollow-stem auger. The layout of the borings, as much as logistically feasible, was perpendicular and parallel to the main axis 

of the Great Miami River. Auger material was described by 

an onsite geologist or the driller. Split-spoon samples were 

Figure 2. Location of wells and piezometers used to determine aquifer characteristics; 

elevation of bedrock surface and lines of stratigraphic sections also are shown.
Methods 5

collected approximately every 5 ft for each boring. The deep 

borings were drilled to refusal. Two-inch monitoring wells 

were installed at each boring site (fig. 2). Four shallow/deep 

well pairs were completed for monitoring of vertical gradients 

at the well field. It was not possible to complete boring 6D as 

a well. Well information and boring characteristics, including 

location and depth and length of screen (table 1), were entered 

into the USGS National Water Information System, Groundwater Site Inventory database. (Lithology and results of grainsize analyses are included in Appendix 1.) 

Two 1-in. piezometers, PZ-1 and PZ-2, were installed 

in the river within several feet of the bank (fig. 2) to measure hydraulic gradient between the river and the shallow 

ground water. The piezometers were driven into the streambed and developed with surging. The 6-in.-long piezometer 

screens were placed approximately 2.1 ft and 3.8 ft below the 

streambed (PZ-1 and PZ-2, respectively). A third piezometer, 

WP-11, was installed near the river prior to the study by the 

Hamilton to New Baltimore Ground Water Consortium. This 

piezometer was driven to approximately 5 ft below the streambed. The screen length is unknown. The water level in this 

piezometer was measured during the course of this investigation. 

 Grain-size analyses were done on 22 of the split-spoon 

samples taken from some of the borings. The samples were 

selected on the basis of the vertical depths within the borings. 

After each sample was dried and weighed, it was placed in 

a vibrating sieve shaker. Stainless-steel sieves were used to 

separate the samples into different size fractions, which were 

then classified according to size; opening sizes were 0.063, 

0.125, 0.149, 0.212, 0.5, 1, 2, and 4 mm. The samples for each 

size fraction were weighed, the resulting data were plotted, 

and subsequent analyses determined D10, D50, and hydraulic 

conductivity (Hazen, 1911). The D10 is the grain size (in millimeters) at which 10 percent by weight of the sample has been 

retained and 90 percent of the sample has passed. Similarly, 

the D50 is the grain size at which 50 percent by weight of the 

sample is retained. The Hazen approximation was used to estimate bulk hydraulic conductivity where the D10 was between 

0.1 and 0.3 mm (Hazen, 1911; Fetter, 1994):

where K is bulk hydraulic conductivity (centimeters per 

second) and C is a coefficient assigned to the sample based on 

the characteristics of the D10 (centimeters). 

The following shows values for the coefficient C (Fetter, 

1994):

Very fine sand, poorly sorted 40–80

Fine sand with appreciable fines 40–80

Medium sand, well-sorted 80–120

Coarse sand, poorly sorted 80–120

Coarse sand, well sorted, clean 120–150

Local boring 

number

Site identification 

number

Boring 

depth

(feet bls)

Altitude, top 

of casing

(feet)

Well diameter 

(inches)

Well 

depth

(feet bls)

Screened interval 

(feet bls)

Top Bottom 

1S 392519084322400 43.0 591.13 2 35.5 24.0 34.0 

1D 392519084322401 70.5 590.86 2 70.5 64.0 69.0

2S 392518084322800 40.5 591.82 2 40.5 34.0 39.0

2D 392518084322801 54.0 591.42 2 52.0 44.5 49.5

3S 392522084322900 49.0 588.89 2 41.86 30.36 40.36

3D 392522084322901 75.15 588.63 2 75.15 68.65 73.65

4D 392518084322300 71.3 591.41 2 71.3 64.8 69.8

5S 392523084322400 29.84 590.74 2 29.84 23.34 28.34

5D 392523084322401 64.95 589.65 2 64.95 58.45 63.45

6S 392525084322300 28.81 588.07 2 28.81 17.31 27.31

6D __ 68.0 __ __ __ __ __

PW 392519084322500 138.21 592.45 18 134.92 87.92 134.92

Table 1. Boring and well information for Hamilton North Well Field aquifer study. 

K=C(D10)2 (1)
6 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

A multiple-well aquifer test was done April 7–11, 2003, 

by pumping a production well in the Hamilton North Well 

Field. All other production wells at the Hamilton North Well 

Field were turned off about 1 month before the study and were 

not pumping for the period of study. Pressure transducers 

installed in the monitoring wells recorded water levels prior 

to, during, and after the aquifer test. A pressure transducer 

also was installed by the Hamilton to New Baltimore Ground 

Water Consortium in a monitoring well, HNC-1D, approximately 8 mi north of the Hamilton North Well Field (fig. 1); 

these data were collected from March 13 until April 30, 2003. 

Periodic manual water-level measurements were made with an 

electric measurement tape to verify the water levels recorded 

by the pressure transducers. Water levels also were measured 

by electric tape at the piezometers—water-level measurements of the river (outside of the piezometers) and inside the 

piezometers were made before, during, and after the aquifer 

test. Measurements of river stage also were made at a bridge 

on U.S. 127 (fig. 2) by use of a weighted steel tape. These 

measurements were made several times during the study and 

compared to measurements made at the USGS streamflowgaging station Great Miami River at Hamilton (03274000) 

(fig. 1; Shindel and others, 2004). 

All borings and other measurement sites were surveyed 

by use of standard differential Global Positioning System 

(GPS) procedures. A total station surveying instrument was 

used where it was not possible to receive satellite signals for 

the GPS instrument and for cross checks of the GPS instrument. The maximum error in measurements in latitude and 

longitude (spatially) is approximately 0.1 ft and in z (altitude), 

approximately 0.05 ft. 

Hourly barometric pressure data for the same period as 

the water-level measurements were downloaded from the 

National Climatic Data Center (www.ncdc.noaa.gov) for the 

Butler County Regional Airport (station HAO; fig. 1). A barometric pressure rise and fall over a period of no pumping and 

static gage height in the Great Miami River (January 26–27 

and February 20–21, 2003) was chosen to determine barometric efficiency (BE) (Todd, 1980):

where C is a conversion factor (0.833 in. Hg/ft H2O) and 

δH is change in water level (feet) due to δP, a change in barometric pressure (inches Hg). 

Commercially available software, AQTESOLV (HydroSOLVE Inc., 1997), was used for the analysis of the aquifer-test data to determine aquifer hydraulic properties and to 

determine whether local clay units act as barriers to downward 

flow to pumping wells. Using this software, an analytical solution to flow in a confined, two-aquifer system (Neuman and 

Witherspoon, 1969) was tested for use on the data collected 

during this study. Assumptions for this solution are that the 

aquifer and confining unit have infinite areal extent and are 

homogeneous, isotropic, and of uniform thickness. Additional 

assumptions are that the pumping well fully penetrates the 

aquifer, that flow to the pumping well is horizontal, and that 

flow is released instantaneously from storage with decline of 

hydraulic head. AQTESOLV was also used to test an analytical solution for unsteady flow to a partially penetrating largediameter well in an unconfined aquifer with delayed gravity 

response (Moench, 1997). Assumptions for this solution are 

that the unconfined aquifer has infinite areal extent, is homogeneous, and is uniform in thickness. 

Ground-Water System

The geologic setting and lithology discussed in this section are important factors for determining areal recharge and 

permeability characteristics within buried-valley systems. 

Ground-water levels are indicative of local ground-water flow 

directions within the ground-water system; comparisons are 

made to the surface-water levels to examine surface-water/

ground-water relations in the lower GMR-BVAS.

Geologic Setting and Lithology

The bedrock underlying the lower Great Miami River 

valley consists of Ordovician interbedded limestone and shale. 

The bedrock was incised by glacially fed streams during the 

several glacial events of the Pleistocene era. The unconsolidated material deposited by the glacially fed streams consists 

of weakly stratified sand, silt, and gravel interspersed with 

some clay or till lenses. The till lenses are identified by the 

gray or blue color, hardness, dryness, and inclusion of gravel 

(Klaer and Thompson, 1948; Spieker, 1968). The till lenses 

were originally laid down as clay-rich layers during glacial 

recession; subsequent glacial advances and periglacial streams 

dissected these layers into discontinuous lenses. Outside the 

limits of the BVAS, glacial till caps the upland areas (Spieker, 

1968). Well yields in the area are somewhat indicative of 

varying depositional environments and glacial material types 

(fig. 1) and generally correspond to Spieker’s hydrogeologic 

environments (Spieker, 1968), which were based on variations in hydrology and geology, especially in terms of aquifer 

properties. 

Driller’s descriptions and split-spoon cores from the 

drilling program yielded valuable insight into the heterogeneity of the lower GMR-BVAS and information on grain-sizes 

and relative hydraulic conductivities at the Hamilton North 

Well Field (Appendix 1). Geologic cross sections derived 

from drillers’ descriptions of borings through the north part 

of the well field are shown in figures 3 and 4. The sections 

show the discontinuous clay/till layers that are typical in the 

lower GMR-BVAS (CH2M-HILL, 1992). At the north end of 

the Hamilton North Well Field, boring 5D (fig. 2) intersected 

a significant clay layer from 24 to 53 ft (Appendix 1); boring 6D, which is approximately 200 ft from the Great Miami 

BE=C*δH/δP (2)
Ground-Water System 7

River, also intersected clay at 24 ft, which continued to the 

bottom of the boring at 74 ft. Boring 4D contains a thin clay 

layer from 24 to 26 ft. Borings 1S and 1D (fig. 2) had clay 

only near the top of the borings (about 2–10 ft below land 

surface), but silt and sand was found in 1D from 45 to 69 ft. 

Borings 2S and 2D illustrate the variable nature of the aquifer 

material over very short lateral distances (< 10 ft)—boring 2D 

had clay or clay and gravel with variable wetness from a depth 

of approximately 26 ft to 44 ft; in boring 2S, clay and gravel 

were found only from 25 to 28.5 ft with little or no clay and 

saturation to 41 ft. (The same geologist logged both borings.) 

Lithologic descriptions were available only for the screened 

interval of the production well PW (figs. 3 and 4). 

Grain-size analyses show the variability of the aquifer 

material and of the units that may act locally as confining 

units. For aquifer materials described, the median D10 grain 

size (described by driller’s descriptions that do not include 

“clay”) was 0.12 mm, with a standard deviation (s) of 0.17. 

The median D50 of the same material was 1.3 mm (s=2.5). 

For locally confining units including “clay” in the lithologic 

descriptions, the median D10 was 0.04 mm (s=0.3); the median 

D50 was an order of magnitude less than that of the aquifer 

material—0.1 mm (s=0.7). 

Figure 3. Stratigraphic section A-A’ through the north part of the Hamilton North Well Field, Hamilton, Ohio. (Line of 

section shown in fig. 1.)
8 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

Recharge

Recharge to the lower GMR-BVAS is primarily through 

either areal distribution of precipitation or infiltration 

through the banks and bottom of the Great Miami River and 

its tributaries (Klaer and Thompson, 1948; Spieker, 1968; 

CH2M-HILL, 1992; Sheets and others, 2002). Areal recharge 

to the ground-water system varies spatially with soil type and 

surficial geology. Generally, areal recharge estimates for the 

lower GMR-BVAS are similar to those in the upper GMRBVAS, the probable range being from 4 in/yr in the upland 

areas where glacial till lies at the surface to as much as 15 in/

yr in the central part of the lower GMR-BVAS (Dumouchelle, 

1998). A near-surface clay layer underlies the north part of 

Hamilton North Well Field (figs. 3 and 4), but it does not 

extend laterally and may not inhibit areal recharge. 

Infiltration from streams occurs where the hydraulic head 

in the stream is higher than the hydraulic head in the aquifer; 

for example, during high flow in streams (resulting in what 

may be referred to as “bank storage”) or when the hydraulic 

head in the aquifer is artificially lowered by pumping (resulting in induced infiltration or bank filtration). Head in the 

aquifer also can be naturally lower than head in the stream. 

This condition is common where small streams cross over the 

boundary of the uplands BVAS and where the streams lose 

water to the aquifer because of the much higher permeability 

aquifer materials of the BVAS than of the upland. Natural 

losses from the larger streams in the central part of the valley 

are rare, because the major streams usually are the regional 

ground-water discharge areas for the BVAS. Near the Hamilton North Well Field, a thick (>20 ft) clay layer was found 

at boring 6D (fig. 3). This clay layer may extend under the 

Figure 4. Stratigraphic section B-B’ through the Hamilton North Well Field, Hamilton, Ohio. (Line of 

section shown in fig. 1.)
Ground-Water Flow Directions 9

Great Miami River; borings directly across the Great Miami 

River from the Hamilton North Well Field also indicate a clay 

layer at about 30 ft below land surface (altitude about 570 ft; 

C. Randy Bishop, ENSR International, written commun., 

2004). Generally, the clay/till layers in this part of the lower 

GMR-BVAS do not appear to be laterally continuous (fig. 3), 

but the thickness of the clay layer at boring 6D and its presence across from the well field may indicate that flow from the 

Great Miami River to production wells is somewhat restricted.

Ground-Water Flow Directions

Most of the ground water within the GMR-BVAS is from 

recharge. A small amount of ground water enters or leaves the 

GMR-BVAS through the underlying bedrock. The permeability of the bedrock is usually assumed to be at least 2 orders of 

magnitude lower than that of the GMR-BVAS, but the upper 

few feet of the bedrock is assumed to be more permeable 

because of weathering (Dumouchelle and others, 1993; U.S. 

Department of Energy, 1995). Because of the low permeability 

of the Ordovician bedrock, it is seldom used for water supplies, so water-level data for the bedrock uplands are scarce. 

Water levels in the upper bedrock probably mimic water levels 

in the till covering the bedrock and ground-water flow from 

the upper bedrock probably is toward the lower GMR-BVAS. 

Ground-water flow within the bedrock usually is not considered an important component of flow within the lower GMRBVAS, but discharging wells near the BVAS and bedrock 

contact may be affected by induced flow from bedrock. Water 

quality in the Ordovician bedrock generally is considered poor 

because of high sodium and chloride concentrations (Sheets 

and others, 1994). 

Ground-water levels in the GMR-BVAS were measured 

from October 2002 through July 2003 in the wells completed 

to determine the direction of ground-water flow for this study. 

In figures 5 and 6, long-term water-level elevations in shallow and deep wells are compared to the water level elevation 

in the Great Miami River. Water-level elevation for the river 

was calculated by means of linear regression (r2=0.99) of the 

gage height at the river at Hamilton (USGS streamflow-gaging station 03274000) and about 20 manual measurements 

of water levels during the course of the study at the U.S. 127 

bridge just north of the Hamilton North Well Field (Appendix 2; Shindel and others, 2004). The shallow and deep wells 

show similar trends relative to the Great Miami River—from 

October to mid-November 2002, water levels from all wells 

were recovering, probably because of reduced pumping at 

the Hamilton North Well Field. After mid-November 2002, 

water-level fluctuations in the Great Miami River from rainfall/runoff were transmitted to each of the monitoring wells, 

both shallow and deep. Periodic pumping in the well field in 

December 2002 and January 2003, and then again after March 

2003, caused sharp declines in the ground-water hydrographs 

(figs. 5 and 6). 

Water-level elevations in the piezometers generally 

mimicked water-level elevations in the Great Miami River, 

especially during March through April 2003 (fig. 5; Appendix 

2). Water-level gradients between the piezometers and the 

river were not conclusive in terms of defining a losing or gaining stream reach and may have been due to areas of reduced 

streambed permeability, improper placement of piezometers, 

or frequency of data collection (Appendix 2). Water-level 

elevations for HNC-1D, about 8 mi north of Hamilton North 

Well Field (fig. 1), also are shown on figure 6. These water 

levels showed a general decline during the period, corresponding to a decline in Great Miami River levels. 

During periods of no pumping and between rises in the 

Great Miami River water levels, water-level elevation in 

each monitoring well is above water-level elevation in the 

river (fig. 5)—indicating that under these conditions, at least, 

local ground water is discharging to the Great Miami River. 

Water-level configurations are shown in figure 7a for the 

shallow and deep well pairs during a period of no pumping, 

when the stream stage is relatively static (February 2003). 

Water levels in the shallower part of the aquifer indicated 

that, in the shallowest part of the aquifer within 500 ft of 

the Great Miami River, ground-water flow was toward the 

river. At distances greater than 500 ft from the river, shallow 

ground-water flow was away from the river. Water levels for 

the deeper wells indicate that ground-water flow was away 

from the river (fig. 7a). Horizontal hydraulic gradients during 

periods of no pumping and relatively low stream stage were 

small (≈0.0005 ft/ft). After the onset of water-level rises in 

the river, however, water levels in the wells were lower than 

river levels, indicating stream loss to the aquifer. In figure 7b, 

water-level configurations are shown for the shallow and deep 

well pairs during a period of no pumping and a stream-stage 

peak (January 2003). Ground-water flow was away from the 

river for both sets of wells, and the horizontal hydraulic gradient was much higher than when stream stage was relatively 

low (≈0.001 ft/ft). 

Examination of water levels during a stream-stage recession revealed additional aspects of the stream/aquifer interaction in this area of the lower GMR-BVAS. Water levels in 

shallow and deep monitoring wells along a potential flow path 

to and from the river (cross section A-A’, fig. 3) are shown 

in figures 8 and 9. At a peak of the stream hydrograph during a runoff event in early January 2003, water levels in the 

stream were higher than each successive water level in wells 

along a potential shallow and deep flow path (fig. 8, Great 

Miami River >6S>5S>1S>2S; or fig. 9, Great Miami River 

>5D>1D>2D). For example, as the water level in the river 

receded and dropped lower than water levels in the shallow 

wells (fig. 8), the water level in well 6S, closest to the river, 

fell below that of 5S and neared the water level in 1S before 

river stage increased again on February 5, 2003. The difference in the water levels between shallow monitoring wells 

also got smaller as the river stage receded, indicating that 

equilibrium between the Great Miami River and the shallow 

aquifer was not reached between the two increases in stage. 
10 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

An examination of the water-level records for the period (figs. 

5 and 6) indicated that either pumping or runoff prevented the 

aquifer from reaching equilibrium with the Great Miami River 

during the measurement period. The deeper wells do not show 

such a marked response in the short-term hydrograph (fig. 

9); but over a longer period (fig. 6), water levels and hydraulic gradients acted much the same way as in the shallower 

aquifer. This complex cycle of gains and losses to the aquifer 

from the Great Miami River indicates that some type of bank 

storage was an active process in this part of the lower GMRBVAS.

Influences on ground-water levels in addition to stream 

stage may include barometric pressure, earth tides, and potentially transient pressure on the aquifer from passing trains. 

As barometric pressure falls, and atmospheric pressure on a 

confined or semiconfined aquifer decreases, water levels in 

wells completed in these aquifers rise; as barometric pressure 

rises, water levels fall (Freeze and Cherry, 1979). Water levels 

in wells completed in unconfined aquifers are not typically 

affected by changes in atmospheric pressure because the atmospheric pressure is transmitted directly to the water table in the 

aquifer and the well. Barometric pressure is shown in figures 

5, 6, 8, and 9; the deep monitoring wells and well 2S show an 

indication of an inverse correlation between barometric pressure and water level. The screen in well 2S lies immediately 

beneath a clay unit found during borehole drilling. The water 

levels in wells 1S, 5S, and 6S show little effect from barometric pressure. A regression analysis between water levels in 

the monitoring wells and barometric pressure during a period 

of nonpumping was done, and barometric efficiencies ranged 

Figure 5. Water levels in shallow monitoring wells at Hamilton North Well Field and in the Great Miami River, and a 

barograph for a weather station at Butler County Regional Airport.
Ground-Water Flow Directions 11

from 6 to 20 percent (6S and 2S, respectively); however, the 

effect of stage changes in the Great Miami River on water 

levels in the wells complicated the analysis. The range of 

barometric efficiency for confined aquifers usually is in the 

range of 20 to 75 percent (Freeze and Cherry, 1979). 

Another possible influence on water levels in wells of the 

lower GMR-BVAS is earth tides effects (Todd, 1980; Ritzi 

and others, 1991). Earth tides are due to the Earth’s attraction to the moon and sun and occur at diurnal and semidiurnal 

cycles. An amplitude spectrum analysis of water levels in the 

BVAS indicates that the tidal component for the monitoring 

wells, if present, is obscured by the atmospheric component 

(barometric pressure). A shallow, unconfined or semiconfined 

aquifer usually does not exhibit earth-tide effects unless the 

saturated thickness is large and porosity is very low (Bredehoft, 1967). 

The Hamilton North Well Field is next to a heavily used 

railroad that also could potentially affect water levels at the 

well field (fig. 2). External loads can affect confined aquifers 

by compressing the aquifer and increasing the hydrostatic 

pressure (Todd, 1980). The lateral discontinuity of confining 

units may decrease this effect, but it may be important locally. 

Water levels in monitoring wells used for this study were not 

obviously affected by railway traffic, based on either hourly 

measurements or more frequent data collection during the 

aquifer test (a measurement every second). 

Figure 6. Water levels in deep monitoring wells at Hamilton North Well Field and in the Great Miami River, and a 

barograph for a weather station at Butler County Regional Airport.
12 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

Figure 7. Water-level contours in Hamilton North Well Field during A, no pumping, stream stage 

static (Feb. 20, 2003), B, no pumping,stream-stage peak (Jan. 4, 2003), C, upper part of aquifer and 

D, lower part of aquifer during pumping, stream recession (April 11, 2003)
Ground-Water Flow Directions 13

Figure 8. Water levels in the Great Miami River and in shallow wells along a ground-water-flow path to the Great Miami 

River, and a barograph for a weather station at the Butler Regional Airport, Hamilton, Ohio.
14 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

Estimation of Hydraulic Properties

Hydraulic properties of the aquifer at the Hamilton North 

Well Field were estimated by use of (1) grain-size analyses 

of samples collected from borings, and (2) a multiple-well 

aquifer test at the well field in April 2003. The results of these 

studies are given in the paragraphs that follow. 

Estimated bulk hydraulic conductivity for selected core 

samples, based on grain-size analyses and the use of the Hazen 

equation (Hazen, 1911), ranged from 25 to 1,200 ft/d (Appendix 1). The method is generally only applicable to sands with 

an effective grain size (D10) between 0.1 and 3.0 mm (Fetter, 

1994). The arithmetic and geometric means of bulk hydraulic 

conductivities of the aquifer material at the Hamilton North 

Well Field, based on these criteria, are approximately 240 ft/d 

and 89 ft/d, respectively. 

An existing production well (PW, fig. 2) was pumped 

for approximately 94 hours during April 7–11, 2003, at an 

average rate of 2,830 gal/min; the pumping rates during this 

period varied between 2,700 and 3,000 gal/min. Water levels 

were monitored by use of transducers and hand measurements 

during this period, with more frequent data collection (approximately 1 reading per second) at the beginning of pumping. 

Recovery of water levels was also monitored after cessation 

of pumping. Water-level configurations for the shallow and 

deep well pairs near the end of pumping are shown in figure 

7c and 7d. Water levels from the shallow wells in each pair 

Figure 9. Water levels in the Great Miami River and in deep wells along a ground-water-flow path to the Great 

Miami River, and a barograph for a weather station at the Butler Regional Airport, Hamilton, Ohio.
Estimation of Aquifer Hydraulic Properties 15

(fig. 7c) and shallow flow gradients (≈0.003 ft/ft) indicate 

that shallow ground-water flow is away from the river and 

toward the production well; a small water-level depression is 

found just south of the production well (fig 7c). Water levels 

from the deeper well in each well pair (fig. 7d) show a marked 

water-level depression around the production well. The configuration of the water levels for the shallow and deeper parts 

of the aquifer indicates horizontal flow from the river in the 

upper part of the aquifer (on top of the clay layer found in boring 6D), toward the production well. As this horizontal flow 

reaches leaky (silty) areas or holes in the clay confining unit, 

vertical flow becomes dominant. 

The water levels measured during pumping were converted to drawdown (static water-level elevation prior to 

pumping minus water-level elevation during pumping). During the course of the aquifer test, barometric pressure changed 

approximately 0.33 in. Hg; this corresponds to a maximum 

barometrically induced change of water level of about 0.07 

ft (from well 2S), on the basis of a barometric efficiency of 

20 percent. The maximum change of water level because of 

pumping and barometric pressure changes was about 3.1 ft, 

corresponding to a maximum barometric pressure effect of 

less than 2.5 percent. For this reason, water levels were not 

corrected for barometric pressure. Water levels in wells also 

were not corrected for earth tides and loading from passing 

trains. 

Because water levels in the aquifer respond to rises and 

falls in the river stage, it is likely that water levels in the aquifer were generally declining during the aquifer test because of 

a recession of the river (figs. 5, 6). The water levels in each of 

the observation wells were corrected for this recession by use 

of linear interpolation between water levels just prior to the 

start of the aquifer test and water levels about 13 days after 

the start of the test (about 9 days after cessation of pumping). 

This is when minimal drawdown is expected because of the 

pumping during the aquifer test and the impending rise in the 

Great Miami River hydrograph. Although a linear interpolation may not match the recession of the ground-water hydrographs exactly, the errors are expected to be small relative 

to the total drawdown. The corrections ranged from 0.18 to 

0.21 ft, ranging from 4 to 16 percent of the total drawdown at 

the monitoring wells. 

Because the monitoring wells and production well partially penetrate the aquifer system, drawdowns in the wells, 

especially those near the production well, are less than what 

would be expected if the wells were fully penetrating. Drawdown for monitoring wells was corrected by use of an approximation by Weeks (1969). The largest corrections were for 

wells 1S, 1D, 4D, 2S, 2D, and 5S (3.01, 1.60, 0.14, 0.05, 0.04, 

and 0.02 ft, respectively). The corrections for the remaining 

wells were 0.01 ft or less. 

In figure 10, the maximum drawdown at approximately 

3.92 days (94 hours) from the beginning of the aquifer test 

(corrected for river stage and partial penetration) is plotted 

against monitoring-well distance from the pumping well. The 

wells were classified as to whether they were completed above 

or below a clay or silt layer that may act as a semiconfining 

unit. The distance-drawdown plot and a closer inspection of 

the lithology indicate that a silty sand layer from 45 to 69 ft 

may be a local confining unit for well 1D (Appendix 1, fig. 1-

1). Wells 2S and 2D are both completed immediately beneath 

a clay unit (fig. 3); wells 3S and 3D also are completed in 

similar horizons in the BVAS (fig. 4). The clustering of maximum drawdown for wells 2S, 2D, 3S and 3D suggests that 

they are all completed in similar horizons as 1D, 4D and 5D. 

The maximum drawdown of well 1S indicates that it is likely 

not completed in the same subunit of the BVAS that well 1D 

is completed in. Given the lithologic descriptions and the separation of maximum drawdown (fig. 10), the part of the aquifer 

in which wells 1S, 5S, and 6S is completed is at least partially 

separated from the part of the aquifer in which the other wells 

and the production well are completed. A conceptual model 

based on these results is that the upper part of the BVAS in 

this area is supplying water to a lower, semiconfined aquifer. 

Linear regression was used to estimate transmissivity 

and the storage coefficient for each set of wells, based on the 

formulas by Cooper and Jacob (1946) and Jacob (1950):

T=C*Q/∆S and (3)

S=D*T*t/r0

2 (4)

where T is transmissivity (feet squared per day)

C, D are coefficients that depend upon the units used 

(0.367 and 2.24, respectively),

Q is discharge rate at pumping well (cubic feet per day) 

∆S is change in drawdown over one log cycle of distance 

(feet), 

S is storage coefficient,

t is time since pumping started (days), and

ro is intercept of extended straight line to zero drawdown 

(feet).

For the wells completed below the semiconfining unit, 

the calculated transmissivity is 8.19x104 ft2/d, which, assuming an aquifer thickness of 150 ft, corresponds to a hydraulic 

conductivity of 546 ft/d. For the wells completed above the 

semiconfining unit, the calculated transmissivity is 8.30x104

ft2/d, corresponding to a hydraulic conductivity of 553 ft/d, 

also assuming an aquifer thickness of 150 ft. Storage coefficients for the wells below and above the semiconfining unit 

are 0.0089 and 0.3, respectively. These calculated transmissivities and storage coefficients are in the upper range for this 

type of glacial material. 

A composite drawdown plot (fig. 11 A, B) can also be 

used to analyze drawdown data for this system to support or 

refute the conceptual model. Analytical solutions of drawdown in a confined two-aquifer system were developed by 

Neuman and Witherspoon (1969). Drawdown in wells 1D, 2D, 

3D, 4D, and 5D, which are below the semiconfining unit, is 

shown in figure 11A. The best-fit Neuman and Witherspoon 

(1969) type curves also are shown. Because the Neuman and 
16 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

Witherspoon solutions do not account for partial penetration, 

drawdown for later times in well 1D are corrected for partial penetration, by means of a technique by Weeks (1969). 

The type curves shown are based on the transmissivities and 

storage coefficients of the lower and upper aquifer (T, T’, 

S, S’, respectively) and two dimensionless parameters (1/B 

and ß/r), that are functions of the distance of the observation 

well from the pumping well, thicknesses of the aquifers and 

confining units, and hydraulic conductivities of the lower and 

upper aquifers and the semiconfining unit. The small value 

of the dimensionless parameters (1/B and ß/r) indicates that 

downward leakage through the semiconfining unit may be 

considerable; as these parameters get smaller, the solution 

of Neuman and Witherspoon (1969) approaches that of the 

Theis (1935) solution. (See Theis type curve for 1D, fig. 11A.) 

However, as the dimensionless parameters get larger, composite drawdown curves show a delayed response, indicating that 

leakage through the semiconfining unit is less. The remaining wells completed beneath the semiconfining unit (2S and 

3S) are shown in figure 11B, along with type curves shown 

for larger values of ß/r. Drawdown in the wells completed in 

the upper unconfined part of the aquifer (1S, 5S, and 6S; fig. 

11B) shows what would be expected from pumping in a lower 

aquifer at least partly separated from the aquifer in which the 

wells are completed (Neuman and Witherspoon, 1969, p. 88). 

Drawdown is much less than what would be expected if they 

were completed in the same aquifer (figs. 10 and 11), and the 

response to pumping is muted and somewhat delayed. 

Figure 10. Maximum drawdown corrected for river stage and partial penetration, which was measured 94 

hours from start of aquifer test against monitoring well distance from pumping well, used to calculate transmissivity and storage coefficient for wells 1D, 4D, and 5D.
Estimation of Aquifer Hydraulic Properties 17

Figure 11. Composite drawdown for monitoring wells at Hamilton North Well Field (A, deep wells; B, 

shallow wells). Calculated type curves (Neuman and Witherspoon, 1969) also are shown for selected 

monitoring wells. (1/B and ß/r are dimensionless parameters, functions of the distance of the observation 

well from the pumping well, thicknesses of the aquifers and confining units, and hydraulic conductivities 

of the lower and upper aquifers and the semiconfining unit.)
18 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

Figure 12. Composite drawdown for monitoring wells at Hamilton North Well Field (A, deep wells; B, 

shallow wells). Calculated type curves (Moench, 1997) also are shown for selected monitoring wells. (1/B 

and ß/r are dimensionless parameters, functions of the distance of the observation well from the pumping well, thicknesses of the aquifers and confining units, and hydraulic conductivities of the lower and 

upper aquifers and the semiconfining unit.)
Summary and Conclusions 19

Using curve matching and the solutions of Neuman and 

Witherspoon (1969), the resultant T, K (based on aquifer 

thickness below the semiconfining unit of 110 ft), and S for 

the semiconfined aquifer are in a reasonable range, averaging 

50,000 ft2/d, 450 ft/d, and 0.0005, respectively (fig. 11). The 

calculated hydraulic conductivities from the aquifer test are 

higher than those calculated from grain-size analyses and are 

at the high end of what can be expected for this type of glacial 

material. This difference is likely due to the scale effect of 

hydraulic conductivity, whereby the hydraulic conductivity 

depends on the scale of the tests conducted to determine the 

hydraulic properties and is proportional to the volume of material sampled (Neuman, 1990; Schulze-Makuch and others, 

1999). An estimated hydraulic conductivity for the semiconfining unit (approximately 0.2 ft/d) and for the upper unconfined aquifer (200 ft/d, based on an assumed thickness of 15 

ft) were also obtained by use of the Neuman-Witherspoon 

solution and are in a reasonable range for these materials. 

A second conceptual model can be examined by attempting to match other analytical solutions to the observed 

drawdown data. Because the semiconfining unit seems to 

be variably leaky and discontinuous, especially in the vicinity of the production well, the aquifer system may act as a 

single, unconfined aquifer. The Moench (1997) analytical 

solution can be used to test whether the aquifer system acts as 

an unconfined aquifer. Figure 12 shows the same composite 

drawdown data as figure 11, except that type curves for the 

Moench solution are shown. The Moench solution accounts 

for partial penetration, so the late-time drawdown data for 

well 1D are not corrected. For the deeper wells (fig. 12A), a 

reasonable match can be obtained between the observed data 

and Moench type curves, with the resulting hydraulic properties similar to those from the Neuman-Witherspoon (1969) 

solution: T=50,000 ft2/d, K=333 ft/d (based on unconfined 

aquifer thickness of 150 ft), S=0.0004, and specific yield =0.2. 

To obtain this match, the ratio of vertical hydraulic conductivity to horizontal hydraulic conductivity (Kz/Kr) equals 0.2, 

ostensibly meaning vertical ground-water flow is somewhat 

restricted, either from significant horizontal stratification of 

outwash sediments or the presence of less permeable sediments within the aquifer. The Moench solution also accounts 

for drainage of water from storage by means of the factor α1; 

the closer to zero α1 becomes, the more the upper-boundary 

value problem approaches that of a confined aquifer (Moench, 

1997, p. 1399). To match the observed drawdown data with 

the Moench type curves, α1 was required to be 1.2 x 10-6, indicating that drainage from storage above the aquifer is limited 

or that the aquifer is confined or semiconfined. 

Moench type curves and drawdowns from the other wells 

completed below the potential semiconfining unit (wells 2S 

and 3S) are shown in figure 12B. The Moench type curves do 

not match the drawdown data as well as the Neuman-Witherspoon type curves do (fig. 11B). This finding indicates that 

the aquifer system at Hamilton North Well Field can best be 

treated as a two-aquifer system, with a semiconfining unit 

separating an upper, unconfined aquifer and a lower, semiconfined aquifer. 

Summary and Conclusions

The buried-valley aquifer at the Hamilton, Ohio, North 

Well Field consists primarily of unconsolidated sand and 

gravel, glacial outwash deposits. The sand and gravel aquifer 

is interspersed with variably discontinuous clay or silt layers 

that cause locally confined or semiconfined conditions. 

A cooperative drilling and water-level monitoring program conducted by the USGS and the Hamilton to New Baltimore Ground Water Consortium at the Hamilton North Well 

Field provided information on the variable lithology of the 

aquifer and the effects of various external forces on water levels and flow directions in the aquifer. The grain-size analyses 

of aquifer sediments indicate that the D10 and D50 grain sizes 

of the clay-rich sediment are nearly an order of magnitude less 

than those of the aquifer material. Bulk hydraulic conductivities calculated from the grain-size analyses in the sand-size or 

greater part of the aquifer yielded a geometric mean of 89 ft/d 

and an average bulk hydraulic conductivity value of 240 ft/d. 

Of all factors influencing static water levels in the aquifers, the stage of the Great Miami River has the greatest effect, 

indicating a connection between all parts of the aquifer and the 

river. Bank storage is an important hydrodynamic process in 

this aquifer system. External loading from barometric pressure 

affected water levels in deep monitoring wells and in a well 

screened beneath a clay unit but the effect of stage changes 

in the Great Miami River on water levels in the wells complicated the analysis. 

A 94-hour aquifer test was done at the Hamilton North 

Well Field during April 7–11, 2003. The resultant drawdown 

was corrected for stream recession and plotted against distance 

and time. In this two-aquifer system, where the upper unconfined aquifer contributes flow to in the lower semiconfined 

aquifer, the transmissivity and storage coefficient for the semiconfined parts of the aquifer were calculated to be 50,000 ft2

/d 

and 5x10-4, respectively. The average hydraulic conductivity 

(450 ft/d) based on the aquifer test is in a reasonable range for 

glacial outwash but is higher than calculated from grain-size 

analyses, indicating a scale effect. Hydraulic conductivities of 

the semiconfining unit and upper unconfined aquifer obtained 

by use of the Neuman-Witherspoon solution are about 0.2 ft/d 

and 200 ft/d, respectively. 

The results of this study show that the part of the lower 

Great Miami River Buried Valley Aquifer System where the 

Hamilton North Well Field is located acts as a two-aquifer 

system. A discontinuity of the clay/till layers beneath the 

Great Miami River and the deeper parts of the aquifer system 

allow a direct response of water levels of the deep monitoring 

wells. 
20 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

Acknowledgments

The authors thank Bruce Whitteberry (City of Cincinnati, 

Hamilton to New Baltimore Ground Water Consortium) for 

logistical assistance and discussions of ground-water hydrology in the lower GMR-BVAS. The authors also thank Tim 

McClellan (City of Hamilton) for logistical assistance at the 

well field. 

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22 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

Appendixes
Appendix 1 23

Figure 1-1. Description of lithology and results of grain-size analyses for wells 1S and 1D.
24 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

Figure 1-2. Description of lithology and results of grain-size analyses for wells 2S and 2D.
Appendix 1 25

Figure 1-3. Description of lithology and results of grain-size analyses for wells 3S and 3D.
26 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

�

Figure 1-4. Description of lithology for well 4D.
Appendix 1 27

�

Figure 1-5. Description of lithology and results of grain-size analyses for wells 5S and 5D.
28 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

�

Figure 1-6. Description of lithology and results of grain-size analyses for well 6S and boring 6D.
Appendix 2 29

Appendix 2. Wat

Well Field, Hamilton, Ohio..

Site ID Local name Measuring-point elevation

392526084322100 PZ-1 575.024

Date and time Water-level elevation 

in piezometer

Water-level elevation 

outside piezometer (ft)

Difference in water-level 

elevation (ft)

12/23/2002 17:00 571.67 571.66 0.01

1/28/2003 17:00 572.36 572.34 0.02

2/18/2003 16:25 572.4 572.38 0.02

3/20/2003 18:57 574.81 574.6 0.21

3/25/2003 15:26 574.56 573.81 0.75

3/25/2003 18:11 574.4 573.74 0.66

3/25/2003 19:57 574.36 573.72 0.64

3/26/2003 17:58 574.24 574.32 -0.08

3/26/2003 19:42 574.24 574.26 -0.02

3/27/2003 17:05 574.31 574.41 -0.1

3/27/2003 19:48 574.32 574.38 -0.06

4/7/2003 14:40 574.79 574.24 0.55

4/7/2003 17:18 574.72 574.6 0.12

4/7/2003 19:52 574.68 574.83 -0.15

4/8/2003 17:11 574.63 574.62 0.01

4/8/2003 18:27 574.65 574.7 -0.05

4/9/2003 17:12 574.63 574.54 0.09

4/10/2003 17:24 574.31 574.02 0.29

4/11/2003 15:19 574.03 573.71 0.32

4/11/2003 17:21 573.98 573.68 0.3

4/11/2003 18:51 573.96 573.66 0.3

4/14/2003 16:38 573.44 573.04 0.4

4/14/2003 18:47 573.44 573.04 0.4

4/17/2003 17:32 573.16 572.78 0.38

5/27/2003 16:45 573.36 572.86 0.5

Site ID Local name Measuring-point elevation

392526084321900 PZ-2 576.083

Date and time Water-level elevation 

in piezometer

Water-level elevation 

outside piezometer

Difference in water-level 

elevation (ft)

12/23/2002 17:00 572.48 572.54 -0.06

1/28/2003 17:00 571.45 571.45 0

2/18/2003 17:00 571.49 571.49 0

3/25/2003 15:29 572.92 572.8 0.12

3/25/2003 18:14 572.89 572.77 0.12

3/25/2003 20:00 572.85 572.74 0.11

3/26/2003 18:03 573.41 573.32 0.09

3/27/2003 17:08 573.54 573.43 0.11

3/27/2003 19:51 573.5 573.39 0.11

4/7/2003 14:51 573.34 573.27 0.07

4/10/2003 17:36 574.29 574.17 0.12

4/11/2003 15:24 574 573.9 0.1

4/11/2003 17:28 573.96 573.86 0.1

4/11/2003 18:58 573.95 573.88 0.07

4/14/2003 16:43 573.34 573.29 0.05

4/14/2003 18:51 573.33 573.28 0.05

4/17/2003 17:34 573.07 573.04 0.03

5/27/2003 16:51 573.21 573.19 0.02
30 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio

Appendix 2. Wat

Well Field, Hamilton, Ohio.—Continued

Site ID Local name Measuring-point elevation

392526084322200 WP-11 576.263

Date and time Water-level elevation 

in piezometer

Water-level elevation 

outside piezometer

Difference in water-Level 

elevation (ft)

1/28/2003 17:00 572.65 572.56 0.09

2/18/2003 17:00 572.63 572.63 0

3/17/2003 15:37 576.14 576.14 0

3/17/2003 19:03 576.08 576.08 0

3/17/2003 20:12 576.04 576.04 0

3/18/2003 16:48 575.54 575.5 0.04

3/18/2003 19:19 575.47 575.41 0.06

3/20/2003 18:54 574.93 574.87 0.06

3/25/2003 15:23 574.19 574.04 0.15

3/25/2003 18:07 574.15 574 0.15

3/25/2003 19:53 574.11 573.97 0.14

3/26/2003 17:51 574.65 574.59 0.06

3/26/2003 19:40 574.59 574.52 0.07

3/27/2003 17:02 574.73 574.7 0.03

3/27/2003 19:45 574.7 574.66 0.04

4/7/2003 14:37 574.55 574.54 0.01

4/7/2003 17:10 574.77 574.84 -0.07

4/7/2003 19:49 575.01 575.12 -0.11

4/8/2003 17:08 574.85 574.92 -0.07

4/8/2003 18:25 574.9 574.95 -0.05

4/9/2003 17:09 574.8 574.8 0

4/10/2003 17:21 574.35 574.29 0.06

4/11/2003 15:17 574.03 573.99 0.04

4/11/2003 17:19 574.01 573.95 0.06

4/11/2003 18:48 573.98 573.92 0.06

4/14/2003 16:30 573.37 573.31 0.06

4/14/2003 18:43 573.36 573.29 0.07

4/17/2003 17:28 573.12 573.02 0.1

5/27/2003 16:41 573.08 573.02 0.06

Site ID Local name Measuring-point elevation

N/A Bridge 608.36

Date and time Depth to water Elevation of river

3/25/2003 15:04 34.6 573.76

3/25/2003 17:52 34.68 573.68

3/25/2003 18:50 34.51 573.85

3/25/2003 20:23 34.58 573.78

3/26/2003 17:28 33.99 574.37

3/26/2003 20:53 34.1 574.26

3/27/2003 17:22 33.92 574.44

3/27/2003 20:13 33.93 574.43

4/7/2003 14:09 34.15 574.21

4/7/2003 16:55 33.8 574.56

4/7/2003 20:21 33.51 574.85

4/8/2003 17:22 33.77 574.59

4/8/2003 18:40 33.79 574.57

4/9/2003 17:25 33.84 574.52

4/10/2003 19:14 34.3 574.06

4/11/2003 14:51 34.55 573.81

4/11/2003 19:55 34.61 573.75

4/14/2003 16:14 35.21 573.15
Appendix 2 31

Appendix 2. Wat

Well Field, Hamilton, Ohio.—Continued

Site ID Local name Measuring-point elevation

392519084322500 PW 592.45

Date and time Water-level elevation 

04/07/03 14:22:00 574.44

04/07/03 17:52:00 574.45

04/07/03 18:01:30 550.45

04/07/03 18:01:35 549.12

04/07/03 18:01:50 548.80

04/07/03 18:09:00 549.10

04/07/03 18:20:00 551.13

04/07/03 18:25:00 551.42

04/07/03 18:31:00 550.97

04/07/03 18:36:00 550.24

04/07/03 19:17:00 548.87

04/07/03 20:09:00 548.13

04/08/03 17:43:00 546.80

04/08/03 18:12:00 546.77

04/09/03 17:31:00 546.24

04/09/03 18:56:00 546.21

04/10/03 18:41:00 545.86

04/11/03 15:49:00 545.57

04/11/03 16:01:20 570.25

04/11/03 16:02:00 570.85

04/11/03 16:02:30 571.06

04/11/03 16:02:50 571.30

04/11/03 16:03:05 571.50

04/11/03 16:03:30 571.54

04/11/03 16:04:00 571.63

04/11/03 16:04:15 571.70

04/11/03 16:04:45 571.77

04/11/03 16:05:00 571.80

04/11/03 16:05:45 571.86

04/11/03 16:06:20 571.97

04/11/03 16:07:00 572.02

04/11/03 16:08:00 572.14

04/11/03 16:09:00 572.15

04/11/03 16:10:00 572.18

04/11/03 16:11:00 572.24

04/11/03 16:12:00 572.28

04/11/03 16:13:00 572.32

04/11/03 16:14:00 572.37

04/11/03 16:15:00 572.39

04/11/03 16:16:00 572.43

04/11/03 16:17:00 572.49

04/11/03 16:21:00 572.53

04/11/03 16:26:00 572.58

04/11/03 17:38:00 573.09

04/11/03 18:35:00 573.18

04/11/03 19:06:00 573.20

04/14/03 17:27:00 573.79
32 Ground-Water Flow Directions and Aquifer Hydraulic Properties, Hamilton, Ohio