NOAA Technical Memorandum GLERL-145

A DIGITAL DATA BASE FOR THE PARTICLE SIZE DISTRIBUTION OF 

BOTTOM SEDIMENTS IN LAKE MICHIGAN

Nathan Hawley

NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI 48105

November 2008

UNITED STATES

DEPARTMENT OF COMMERCE

Carlos M. Gutierrez

Secretary

NATIONAL OCEANIC AND

ATMOSPHERIC ADMINISTRATION

Conrad C. Lautenbacher, Jr.

Administrator
2

NOTICE

Mention of a commercial company or product does not constitute an endorsement 

by the NOAA. Use of information from this publication concerning proprietary 

products or the tests of such products for publicity or advertising purposes is not 

authorized. This is GLERL Contribution No. 1489.

This publication is available as a PDF file and can be downloaded from GLERL’s 

web site: www.glerl.noaa.gov. Hard copies can be requested from GLERL, 

Information Services, 2205 Commonwealth Blvd., Ann Arbor, MI 48105.

pubs.glerl@noaa.gov.
3

TABLE OF CONTENTS

ABSTRACT..................................................................................................................................5

1. INTRODUCTION....................................................................................................................5

2. METHODS ...............................................................................................................................5

Field Measurements .................................................................................................................5

Numerical Methods..................................................................................................................7

3. RESULTS..................................................................................................................................7

4. REFERENCES .........................................................................................................................7

APPENDIX 1. Link to data file (Excel format). 

ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-145/TM-145_Appendix1_LMichiganbottom_sediments.xls

LIST OF TABLES

Table 1. Characteristics of the measured particle size data.........................................................................9

Table 2. Size intervals reported in the data base.........................................................................................9

LIST OF FIGURES

Figure 1. Locations of the bottom samples. A. Cahill collected by Cahill. 

B. Samples collected as part of the Lake Michigan Mass Balance Program. 

C. Samples collected as part of the Environmental Mapping and Assessment 

	 Program (●) or by Hawley (×). D. Samples collected by the U. S. Geological Survey ..........10

Figure 2. Water depth in meters.................................................................................................................11

Figure 3. Mean particle size in phi units....................................................................................................11

Figure 4. Percent of bed with particle diameter >0.062 mm .....................................................................12

Figure 5. Percent of bed with particle diameter <0.062 mm ....................................................................12

Figure 6. Percent of bed in size class 1......................................................................................................13

Figure 7. Percent of bed in size class 2......................................................................................................13

Figure 8. Percent of bed in size class 3......................................................................................................14

Figure 9. Percent of bed in size class 4......................................................................................................14
4

Figure 10. Percent of bed in size class 5....................................................................................................15

Figure 11. Percent of bed in size class 6....................................................................................................15

Figure 12. Percent of bed in size class 7....................................................................................................16

Figure 13. Percent of bed in size class 8....................................................................................................16

Figure 14. Mean particle size (in phi units) versus water depth ................................................................17

Figure 15. Percent of particles >0.062 mm versus water depth.................................................................17
5

A digital data base for the distribution of bottom 

sediments in Lake Erie

Nathan Hawley

ABSTRACT. This document describes a map of the size distribution of bottom 

sediments in Lake Michigan. The data set combines measurements of the bottom 

sediment size distribution made by several previous investigations. The results are 

presented on the same 2 km grid presently used for forecasting waves and currents

in the lake. 

1. INTRODUCTION

Since both nutrients and anthropogenic pollutants may absorb onto and be transported by finegrained suspended material, modeling the transport and deposition of these sediments in the 

Great Lakes has become an area of active research. In addition to making these nutrients and 

pollutants available to the benthic ecosystem, high concentrations of suspended sediment may 

also affect the pelagic food web both by acting as a source of nutrients and by limiting the

amount of light available. This makes modeling of fine-grained material a necessary component 

of the ecological models being developed as part of a basin-wide ecological forecasting system. 

Knowledge of the spatial distribution of the particle size of the bottom sediments in the lakes is a

critical requirement for the development of these models. 

2. METHODS 

Field Measurements

Information on the particle size distribution of Lake Michigan bottom sediments is available 

from several sources: a lakewide survey conducted in 1975 (Cahill, 1981), two other lakewide

surveys conducted in the 1990s (Eadie and Lozano, 1999), nearshore data from the southern 

basin collected by the United States Geological Survey (Poppe et al., 2005), and data collected at 

a limited number of stations in the southern basin (Hawley, unpublished data). The methods used

to collect and analyze the samples varied, so a brief description of each set of measurements is 

given below and in Table 1. 

Sediment size measurements have been traditionally been reported in φ units

Φ = -log (d)/ log(2) (1) 

where d is the particle diameter in mm. The size distribution is usually reported at either half or

whole φ intervals. Since the scale is logarithmic, the range of a φ interval in mm is not constant,

but varies depending upon the actual value of φ. The dividing line between coarse, non-cohesive

sediments (sand and gravel) and fine, cohesive sediments (silt and clay) is traditionally set at 

0.062 mm or φ equal to 4. With the introduction of digital calculators, the need for φ units has

diminished, but many measurements are still based on the φ scale. Here the measurements are

given in mm whenever possible, but the size ranges used are based on φ units.
6

The first (and most comprehensive) lakewide survey of bottom sediments was conducted in 1975

(Cahill, 1981). Surface samples were collected using a Shipek grab sampler at points on a 12

km grid, except for Green Bay where a 7 km grid was used (Fig. 1a). Subsamples were removed

with a 0.05 x 0.05 x 0.03 m box subsampler. The samples were first wet sieved through a 0.062

mm (4 φ) screen to separate the sand and gravel fraction from the silt and mud. The coarse

fraction was then dried and sieved at 0.5 φ intervals between 16 and 0.062 mm, while the silt

and mud were analyzed at 1 φ intervals using pipetting techniques. Unfortunately, the original

measurements have been lost, and the available data lists only the mean, standard deviation, 

skewness, and kurtosis in φ units, and the percentage of sand (diameter greater than 0.062 mm),

silt (0.062-0.004 mm), and clay (less than 0.004 mm). Details of the analytical procedure are

given in Cahill (1981). These samples were collected as part of a five-lake survey conducted

by the Canadian National Water Research Institute. Data from all five of the Great Lakes are 

available (Raukavina, 2004).

Box cores and Ponar samples were retrieved as part of the Lake Michigan Mass Balance

Study (LMMB, Fig. 1b) in 1995 and 1996, and Ponar samples were collected in 1994 for the

Environmental Mapping and Assessment Program (EMAP, Fig. 1c). The particle size distribution 

for all of the samples was determined from the top 0.01 m interval of the samples. Sediments

were first wet sieved through 2 mm and 1 mm sieves. Material retained on the sieves was dried

and weighed, while the material that passed through the sieves was analyzed using a laser optical

particle counter (Horiba LA900). The LMMB samples were measured at 1 φ intervals between

0.5 mm and 0.002 mm, but the EMAP samples were measured at non-standard intervals. Further

details of the procedures are given in Eadie and Lozano (1999).

Samples from southern Lake Michigan were collected by the U.S. Geological Survey during

several studies conducted in the 1980s and early 1990s. These data have been compiled in 

a data base and are available to the public (Poppe et al., 2005). The samples were primarily

collected using either a Van Veen or a Shipek sampler, although some box cores were collected

in deeper water (Fig. 1d). A limited number of samples were also collected using divers or an

underwater vehicle. The particle size distribution was measured on samples collected over

vertical intervals ranging from 0-0.02 m (box cores) and 0-0.03 m (submersible), to 0-0.08 m 

(Van Veen ) or 0-0.1 m (Shipek). For some of the samples, the depth interval was not recorded. 

Particle size distribution was measured using either a rapid sediment analyzer or sieves for the

coarser material and a Coulter particle counter for the finer material (K. McMullen, personal 

communication). Size is reported at one φ intervals between 16 mm and 0.0005 mm.

A few samples were collected by Hawley (unpublished data) in conjunction with deployments

of bottom-resting tripods at several sites in southern Lake Michigan during 1998-2002 (x in Fig. 

1c). Material was collected either by using a Ponar sampler, or from the feet of the tripods as

they were retrieved, and the top 0.02 cm was analyzed. Samples were wet sieved through a 1 mm

screen. The material retained on the screen was dried and sieved at 0.5 φ intervals between 2 mm

and 0.7 mm. The material that passed through the screen was measured using a Malvern 2000

optical particle counter. Results from the two size factions were merged and recorded at one φ

intervals between 0.5 mm and 0.001 mm.
7

Numerical Methods

The field measurements described above were used to interpolate the particle size distribution

on a 2 km grid covering the entire lake (Schwab and Sellers, 1996) using a two-dimensional

linear interpolation function available in Matlab. Schwab and Sellers (1996) also provided the

lake bathymetry for each grid point, and vectors of latitude and longitude that represent the lake 

shoreline and the areas of the larger island in the lake. These values have been used as input to 

generate the figures.

Although the data reported by Cahill (1981) is the most complete geographically, the size 

distribution is only reported for three intervals: sand (greater than 0.062 mm), silt (0.004-.062

mm), and clay (less than 0.004 mm). Therefore the integration of the various data sets was done

in two steps. First each set of measurements used to compute the percentages of coarse (> 0.062

mm) and fine (<0.062 mm) material throughout the lake. A comparison of the results using

only the Cahill data and the results using all of the other data showed that the patterns are very

similar, so all of the data sets were combined and used to interpolate the percentage of fine and

coarse material throughout the lake. Then all of the data except the Cahill measurements were

used to subdivide the interpolated coarse and fine percentages into four size ranges each. The 

characteristics of the eight size classes are given in Table 2.

3. RESULTS

Figures 2 and 3 show the depth and mean particle size (in φ units) throughout the lake, while

Figures 4 and 5 show the percentage of material with diameters greater than and less than

0.062 mm. Similar contour maps for each of the eight size classes listed in Table 2 are shown in

Figures 6-13. The data are also presented in digital form in the excel spreadsheet in Appendix 1. 

The spread sheet also includes the latitudes and longitudes for each of the grid points. The array 

includes many positions on land. Values for these locations are represented by zero for the water

depths and -99 for all of the other parameters.

Several previous investigators have assumed a relationship between water depth and particle

size to determine the mean particle size at a particular location. The data presented here (Figures 

14 and 15), however, show that there is no consistent relationship between the water depth

and either the mean particle size or the fraction of material larger than 0.062 mm. Although in

general both measures decrease with increasing depth, the trend is by no means uniform. The

data presented here may allow one to determine such a relationship for a limited geographical

area within the lake, or they can be used as a base map to interpolate the size distribution at other

points within the lake.

4. REFERENCES

Cahill, R.A. 1981. Geochemistry of recent Lake Michigan Sediments, Circular 517, State 

Geological Survey Division, Illinois Institute of Natural Resources, 94 pp. 

Eadie, B.J. and S. Lozano. 1999. Grain-size distribution of the surface sediments collected 

during the Lake Michigan Mass Balance and Environmental Mapping and Assessment Programs, 
8

NOAA Technical Memorandum ERL GLERL-111. NOAA, Great Lakes Environmental 

Research Laboratory, Ann Arbor, MI, 42 pp. 

Poppe, L.J., S.J. Williams, and V.F. Paskevich. 2005. United States Geological survey East-Coast 

Sediment Analysis: Procedures, Database and GIS data, United States Geological Survey Open 

File report 2005-1001, available online at http://woodshole.er.usgs.gov/openfile/of2005-1001/.

Rukavina, N.A. 2004. NWRI Sediment Archive. Products and Services, available online at www.

nwri.ca.

Schwab, D.J. and D.L. Sellers. 1996. Computerized bathymetry and shorelines of the Great

Lakes, NOAA Data Report ERL GLERL-16. NOAA, Great Lakes Environmental Research

Laboratory, Ann Arbor, MI, 8 pp.
9

Table 1: Characteristics of the measured particle size data.

Data 

base

Collection 

date

Number 

of

samples

Collection

method

Depth 

Interval

(m)

Analysis 

Method

For coarse

Material

Analysis 

method for 

fine material

Cahill 1975 283 Shipek 0-0.03 Sieves Pipette

LMMB 1995-1996 68 Box core 0-0.01 Sieves and laser 

counter Laser counter

EMAP 1994 35 Ponar 0-0.01 Sieves and laser 

counter Laser counter

USGS 1988-1992 490

Van Veen, 

shipek, and 

others

Up to 

0-0.1

Sieves and 

Rapid sediment 

analyzer

Coulter counter

Hawley 1998-2000 16 Ponar 0-0.02 Sieves and laser 

counter Laser counter

Table 2: Size intervals reported in the data base.

Size class Size range Phi range Standard terminology

1 >2 mm <-1 Granule or gravel

2 2-0.5 mm -1- +1 Very coarse and coarse sand

3 0.5-0.125 mm 1-3 Medium and fine sand

4 0.125-0.062 mm 3-4 Very fine sand

5 0.062-0.031 mm 4-5 Coarse silt

6 0.031-0.016 mm 5-6 Medium silt

7 0.016-0.004 mm 6-8 Fine and very fine silt

8 <0.004 mm >8 Clay
10

−88 −87 −86 −85 −84

42

43

44

45

46

A

−88 −87 −86 −85 −84

42

43

44

45

46

B

−88 −87 −86 −85 −84

42

43

44

45

46

C

−88 −87 −86 −85 −84

42

43

44

45

46

D

Figure 1. Locations of the bottom samples. A. Cahill collected by Cahill. B; Samples 

collected as part of the Lake Michigan Mass Balance Program. C. Samples collected as part 

of the Environmental Mapping and Assessment Program (●) or by Hawley (×). D. Samples 

collected by the U. S. Geological Survey.
11

−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

41.5

42

42.5

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46

46.5

0

1

2

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10

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44.5

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45.5

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46.5

−250

−200

−150

−100

−50

0

Figure 2. Water depth in meters.

Figure 3. Mean particle size in 

phi units.
12

−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

41.5

42

42.5

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43.5

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44.5

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45.5

46

46.5

0

10

20

30

40

50

60

70

80

90

100

Figure 4. Percent of bed with 

particle diameter >0.062 mm.

−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

41.5

42

42.5

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43.5

44

44.5

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45.5

46

46.5

0

10

20

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Figure 5. Percent of bed with 

particle diameter <0.062 mm.
13

−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

41.5

42

42.5

43

43.5

44

44.5

45

45.5

46

46.5

0

10

20

30

40

50

60

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80

90

100

−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

41.5

42

42.5

43

43.5

44

44.5

45

45.5

46

46.5

0

10

20

30

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50

60

70

80

90

100

Figure 6. Percent of bed in 

size class 1.

Figure 7. Percent of bed in 

size class 2.
14

−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

41.5

42

42.5

43

43.5

44

44.5

45

45.5

46

46.5

0

10

20

30

40

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−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

41.5

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42.5

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43.5

44

44.5

45

45.5

46

46.5

0

10

20

30

40

50

60

70

80

90

100

Figure 8. Percent of bed in 

size class 3.

Figure 9. Percent of bed in 

size class 4.
15

−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

41.5

42

42.5

43

43.5

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46.5

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10

20

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100

−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

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42.5

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43.5

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44.5

45

45.5

46

46.5

0

10

20

30

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50

60

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80

90

100

Figure 10. Percent of bed in 

size class 5.

Figure 11. Percent of bed in 

size class 6.
16

−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

41.5

42

42.5

43

43.5

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45.5

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46.5

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10

20

30

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−88.5 −88 −87.5 −87 −86.5 −86 −85.5 −85 −84.5 −84 −83.5

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45

45.5

46

46.5

0

10

20

30

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Figure 12. Percent of bed in 

size class 7.

Figure 13. Percent of bed in 

size class 8.
17

0 10 20 30 40 50 60 70 80 90 100

−300

−250

−200

−150

−100

−50

0

% >0.062 mm

water depth in m

Figure 15. Percent of particles 

>0.062 mm versus water depth.

0 1 2 3 4 5 6 7 8 9

−300

−250

−200

−150

−100

−50

0

mean size in phi units

water depth in m

Figure 14. Mean particle size (n phi 

units) versus water depth.