U.S. Department of the Interior 

U.S. Geological Survey

Use of Thematic Mapper Imagery to 

Assess Water Quality, Trophic 

State, and Macrophyte Distributions in 

Massachusetts Lakes

By MARCUS C. WALDRON, PETER A. STEEVES, and 

JOHN T. FINN (Department of Forestry and Wildlife Management, 

University of Massachusetts, Amherst)

Water-Resources Investigations Report 01-4016

Prepared in cooperation with the

Massachusetts Department of Environmental Management

Northborough, Massachusetts

2001
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

The use of trade or product names in this report is for identification 

purposes only and does not constitute endorsement by the 

U.S. Government.

For additional information write to: Copies of this report can be purchased from:

Chief, Massachusetts-Rhode Island District U.S. Geological Survey

U.S. Geological Survey Branch of Information Services

Water Resources Division Box 25286

10 Bearfoot Road Denver, CO 80225-0286

Northborough, MA 01532

or visit our web site at

http://ma.water.usgs.gov
Contents III

CONTENTS

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

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

Study Methods....................................................................................................................................................................... 3

Sampling and Analysis for Water-Quality Characteristics .......................................................................................... 5

Field Observations............................................................................................................................................. 5

Phytoplankton-Chlorophyll Concentration ....................................................................................................... 5

Lake Color......................................................................................................................................................... 5

Dissolved Organic Carbon Concentration......................................................................................................... 8

Analytical Quality Assurance............................................................................................................................ 8

Quality Assurance of Volunteer Data .......................................................................................................................... 9

Thematic Mapper-Based Assessment of Water Quality and Trophic State........................................................................... 13

Secchi Disk Transparency and Phytoplankton-Chlorophyll Concentration................................................................ 13

Lake Color and Dissolved Organic Carbon Concentration......................................................................................... 15

Thematic Mapper-Based Assessment of Macrophyte Distributions ..................................................................................... 16

Field-Mapping of Macrophyte Distributions .............................................................................................................. 16

Digitization and Processing of Field Maps ................................................................................................................. 17

Image Interpretation .................................................................................................................................................... 18

Observed Versus Predicted Macrophyte Distributions................................................................................................ 19

1996 Predictions Based on 1996 Interpretations............................................................................................... 19

1997 Predictions Based on 1997 Interpretations............................................................................................... 19

1996 Predictions Based On 1997 Interpretations.............................................................................................. 19

Summary and Conclusions.................................................................................................................................................... 26

References Cited ................................................................................................................................................................... 27

FIGURES

1. Map showing locations of study lakes and Landsat-5 Worldwide Reference System paths and rows for 

Massachusetts ........................................................................................................................................................ 6

2. Example of field form used in volunteer field-data collection program................................................................ 10

3. Graphs showing relations between volunteer and U.S. Geological Survey staff measurements of 

(A) Secchi disk transparency; (B) phytoplankton-chlorophyll concentration; (C) color; and (D) surfacewater temperature .................................................................................................................................................. 12

4, 5. Graphs showing:

4. Relations between Secchi disk transparency and phytoplankton-chlorophyll concentration in 

Massachusetts lakes in (A) 1996; (B) 1997; and (C) 1998............................................................................ 14

5. Relations between color and dissolved organic carbon concentration in Massachusetts lakes .................... 16

6. Graphs comparing observed (field-mapped in summer 1996) and predicted (interpreted from July 1996 

Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in 12 

Massachusetts lakes ............................................................................................................................................... 20

7. Maps showing observed (field-mapped in summer 1996) and predicted (interpreted from July 1996 

Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in Whitehall 

Reservoir, Hopkinton, Massachusetts.................................................................................................................... 21

8. Graphs comparing observed (field-mapped in summer 1997) and predicted (interpreted from August 

1997 Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in 12 

Massachusetts lakes ............................................................................................................................................... 22

9. Maps showing observed (field-mapped in summer 1997) and predicted (interpreted from August 1997 

Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in 

Thompson Pond, Spencer, Massachusetts ............................................................................................................. 23
IV Contents

10. Graphs comparing observed (field-mapped in summer 1996) and predicted (interpreted from August 

1997 Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in 12 

Massachusetts lakes ............................................................................................................................................... 24

11. Maps showing observed (field-mapped in summer 1996) and predicted (interpreted from August 1997 

Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in East 

Brimfield Reservoir, Brimfield and Sturbridge, Massachusetts............................................................................. 25

TABLES

1. Thematic Mapper spectral bands ............................................................................................................................ 3

2. Massachusetts lakes for which the distributions of floating, emergent, and submerged macrophytes were 

mapped in 1996, 1997, and 1998 for calibration of Landsat-5 Thematic Mapper imagery ................................... 8

3. Lakes sampled by Massachusetts Water Watch Partnership volunteers concurrently with U.S. Geological 

Survey staff for chlorophyll concentration, Secchi disk transparency, color, and water temperature in 1997 

and 1998.................................................................................................................................................................. 11

4. Landsat-5 Thematic Mapper scenes used to assess water quality and trophic state of Massachusetts lakes ......... 13

5. Thematic Mapper spectral bands and combinations of bands used as models to test for correlations with 

water-quality and trophic-state data for Massachusetts lakes................................................................................. 15

6. Massachusetts lakes sampled in 1996, 1997, and 1998, and numbers of measurements of water-quality 

characteristics used to calibrate Landsat-5 Thematic Mapper imagery.................................................................. 31

7. Lake-water-quality data collected within 24 hours of Landsat-5 Thematic Mapper imaging of the lakes, 

and haze-corrected digital numbers corresponding to the station locations in the images..................................... 37

CONVERSION FACTORS, VERTICAL DATUM, AND ABBREVIATED WATER-QUALITY UNITS

CONVERSION FACTORS

Very small units of length are reported in millimeters (mm), micrometers (μm), or nanometers

(nm). One centimeter equals 10 mm, 1 mm equals 1,000 μm, and 1 μm equals 1,000 nm.

VERTICAL DATUM

Sea level: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)—a

geodetic datum derived from a general adjustment of the first-order level nets of the United States and Canada,

formerly called Sea Level Datum of 1929. 

ABBREVIATED WATER-QUALITY UNITS:

Chemical concentration is reported in milligrams per liter (mg/L) or micrograms per liter (μg/L). Milligrams per liter

is a unit expressing the concentration of chemical constituents in solution as mass (milligrams) of solute per unit

volume (liter) of water. One thousand micrograms per liter is equivalent to one milligram per liter. For concentrations

less than 7,000 mg/L, the numerical value is the same as for concentrations in parts per million. Specific electrical

conductance of water is reported in microsiemens per centimeter at 25 degrees Celsius (μS/cm). Color is reported in

platinum-cobalt units (PCU).

Multiply By To obtain

centimeter (cm) 0.3937008 inch (in.)

cubic meter (m3) 264.17205 gallon (gal)

cubic meter (m3) 35.31467 cubic foot (ft3)

hectare (ha) 2.471 acre

kilometer (km) 0.62137 mile (mi)

meter (m) 3.280840 foot (ft)

milliliter (mL) 0.00026417 gallon (gal)

Water temperature is reported in degree Celsius ( ̊C), which can be converted

to degree Fahrenheit ( ̊F) by the following equation:

 ̊F = 1.8 ( ̊C) +32
Abstract 1

Use of Thematic Mapper Imagery to 

Assess Water Quality, Trophic 

State, and Macrophyte Distributions in 

Massachusetts Lakes

By Marcus C. Waldron, Peter A. Steeves, and John T. Finn

Abstract

During the spring and summer of 1996, 

1997, and 1998, measurements of phytoplanktonchlorophyll concentration, Secchi disk transparency, and color were made at 97 Massachusetts 

lakes within 24 hours of Landsat Thematic 

Mapper imaging of the lakes in an effort to assess 

water quality and trophic state. Spatial distributions of floating, emergent, and submerged macrophytes were mapped in 49 of the lakes at least 

once during the 3-year period. The maps were 

digitized and used to assign pixels in the thematic 

mapper images to one of four vegetation cover 

classes—open water, 1–50 percent floating-andemergent-vegetation cover, 51–100 percent 

floating-and-emergent-vegetation cover, and submerged vegetation at any density. The field data 

were collected by teams of U.S. Geological 

Survey and Massachusetts Department of Environmental Management staff and by 76 volunteers. 

Side-by-side sampling by U.S. Geological Survey 

and volunteer field teams resulted in statistically 

similar chlorophyll determinations, Secchi disk 

readings, and temperature measurements, but concurrent color determinations were not similar, possibly due to contamination of sample bottles 

issued to the volunteers.

Attempts to develop predictive relations 

between phytoplankton-chlorophyll concentration, 

Secchi disk transparency, lake color, dissolved 

organic carbon, and various combinations of 

thematic mapper bands 1, 2, 3, and 4 digital numbers were unsuccessful, primarily because of the 

extremely low concentrations of chlorophyll in 

the lakes studied, and also because of the highly 

variable dissolved organic carbon concentrations.

Predictive relations were developed between 

Secchi disk transparency and phytoplanktonchlorophyll concentration, and between color 

and dissolved organic carbon concentration. 

Phytoplankton-chlorophyll concentration was 

inversely correlated with Secchi disk transparency 

during all three sampling periods. The relations 

were very similar in 1996 and 1997 and indicated 

that 62 to 67 percent of the variability in Secchi 

disk transparency could be explained by the 

chlorophyll concentration. Analysis of color and 

dissolved organic carbon concentrations in water 

samples collected by U.S. Geological Survey field 

teams in 1996–98 indicated that 91 percent of 

the variance in color in Massachusetts lakes can 

be explained by variations in dissolved organic 

carbon.

Areas of open-water, submerged vegetation, 

and two surface-vegetation-cover classes predicted 

from Thematic Mapper images acquired in the 

summer of 1996 closely matched the areas 

observed in a set of field observations. However, 

the same analysis applied to a set of data acquired 

in the summer of 1997 resulted in somewhat 

less reliable predictions, and an attempt to predict 

1996 vegetation-cover areas using the relations 

developed in the 1997 analysis was unsuccessful. 
2 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

INTRODUCTION

Accelerated eutrophication due to changing 

drainage-basin activities is a significant problem 

affecting Massachusetts lakes (Massachusetts Water 

Resources Commission, 1994). This accelerated, or 

cultural, eutrophication is caused by nutrient-rich 

effluents from sewage treatment plants, runoff of fertilizers and animal wastes, stormwater runoff from 

impervious surfaces, leaching from septic systems, and 

increased soil erosion resulting from construction and 

other similar activities. Cultural eutrophication can 

lead to excessive growth of aquatic macrophytes, 

increased turbidity, depletion of dissolved oxygen, and 

subsequent loss of fish habitat. Massachusetts lakes are 

especially susceptible to the problem because most 

drainage basins are heavily developed and most lakes 

are subject to multiple uses. In addition, many lakes in 

Massachusetts were created or enlarged by impounding 

water behind dams, resulting in submerged soils within 

these impoundments that may provide an additional 

source of nutrients affecting the trophic state of the 

lakes. Trophic state, the extent of the effect of eutrophication due to nutrient enrichment, has been difficult 

to quantify in Massachusetts because many lakes 

develop dense beds of aquatic macrophytes in response 

to eutrophication, and most methods for assessing 

trophic state are based on the relative abundance of 

phytoplankton algae and do not take into account the 

biomass of macrophytes (Canfield and others, 1983).

The recently adopted Massachusetts Policy on 

Lake and Pond Management advocates a comprehensive approach to lake eutrophication that integrates 

education, watershed protection, and in-lake management in an attempt to reconcile desired uses of 

Massachusetts lakes with their ability to support those 

uses (Massachusetts Water Resources Commission, 

1994). Central to the Massachusetts Policy on Lake and 

Pond Management is the need to assess lake-water 

quality at regular intervals and to identify trends 

(both negative and positive) in lake trophic state. With 

more than 3,000 named lakes, ponds, and reservoirs 

(for simplicity, the word “lake” will be used throughout 

this report to refer to any open body of water) in 

Massachusetts, the costs and logistical problems associated with a statewide lake-quality-monitoring 

program are substantial.

The development of satellite resources such as 

the Landsat Thematic Mapper (TM) and new techniques for processing and analyzing satellite data offer 

the potential for augmenting the data-collection and 

resource-evaluation efforts of State environmental 

agencies. Landsat images can provide high-resolution 

information concerning a number of important limnologic features, including chlorophyll-a concentration, 

turbidity, color, algal production rates, nutrient concentrations, and surface-water temperatures (Scarpace and 

others, 1979; Verdin, 1985; Raitala, 1986; Shimoda and 

others, 1986). The availability of Landsat images 

dating back to the early 1970s allows for the development of long-term records of properties related to lake 

trophic state and can be used to identify trends (Witzig 

and Whitehurst, 1981; Lillesand and others, 1983).

The U.S. Geological Survey (USGS), in cooperation with the Massachusetts Department of Environmental Management (MADEM), has investigated the 

use of Landsat TM data for Statewide assessment of 

lake quality and trophic state. Measurements of water 

temperature, Secchi disk transparency, color, and the 

concentration of phytoplankton chlorophyll were made 

in 97 lakes during the summers of 1996, 1997, and 

1998, by USGS and MADEM staff and by a team of 

trained volunteers recruited by the Massachusetts 

Water Watch Partnership (MassWWP). The lake measurements were timed to coincide with Landsat-5 TM 

imaging of the State. During the same period, the midto-late-summer distributions of floating, emergent, and 

submerged macrophytes were mapped in 62 lakes, 

again by a combination of professional and volunteer 

field teams. The field data were correlated with data 

extracted from a set of four TM images, each image 

representing the eastern two-thirds of the State.
Study Methods 3

The purpose of this report is to demonstrate 

how Landsat TM data may be used to assess the 

water quality and trophic state of Massachusetts 

lakes and to monitor the distributions of aquatic 

macrophytes. The report describes methods of fielddata collection and procedures used for acquiring 

and processing the TM data. Field data collected by 

volunteer water-quality monitoring teams are compared statistically with concurrent measurements 

made by USGS field teams. Results are presented separately for TM-based assessment of lake-water quality 

and trophic state and for TM-based mapping of 

lake-macrophyte distributions. Data collected during 

the study are available via the World Wide Web at 

http://ma.water.usgs.gov/lakesandponds/. 

The authors wish to thank the volunteers and 

staff of the Massachusetts Water Watch Partnership for 

their generous contributions of time and other 

resources to this project.

STUDY METHODS

Landsat-5 orbits the earth at an altitude of 

705 km in a near-polar, sun-synchronous orbit with a 

16-day, 233-orbit repeat cycle. The primary imaging 

instrument on Landsat-5 is the TM, which senses 

reflected light energy in seven spectral bands, three in 

the visible range, three in the near- and mid-infrared, 

and one in the thermal infrared (table 1). The TM sensors have a spatial resolution of 120-by-120 m for the 

thermal-infrared band and 30-by-30 m for the other six 

spectral bands. The sensors can distinguish 256 levels 

of brightness (radiance) in each spectral band for each 

30-by-30 m or 120-by-120 m picture element (pixel). 

The brightness levels are recorded as digital numbers 

(DNs) representing the average radiance measured over 

the ground area corresponding to each pixel.

Table 1. Thematic Mapper spectral bands

Spectral

band

Wavelength range

(micrometers)

Nominal spectral

location Principal Application(s)

1 0.45–0.52 Blue-green Designed for maximum penetration of water. Used for bathymetric mapping of 

shallow water bodies. Also used for distinguishing soil from vegetation and 

deciduous from coniferous trees.

2 0.52–0.60 Green Designed to measure green reflectance peak of vegetation. Useful for assessing 

plant vigor.

3 0.63–0.69 Red Designed to measure light that is strongly absorbed by chlorophyll. Used for 

discriminating vegetation types.

4 0.76–0.90 Near infrared Useful for determining vegetation types, vigor, and biomass. Also used for 

distinguishing shorelines of water bodies.

5 1.55–1.75 Mid-infrared Measures moisture content of soil and vegetation. Penetrates thin clouds. Used 

to distinguish snow from clouds.

6 10.4–12.5 Thermal infrared Nighttime images are useful for thermal mapping and for estimating soil 

moisture.

7 2.08–2.35 Mid-infrared Measures absorption by hydroxyl ions in minerals. Used for mapping 

hydrothermally altered rocks associated with mineral deposits. Also sensitive 

to vegetation moisture content.
4 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

Landsat imagery is subdivided into scenes 

based on a Worldwide Reference System (WRS) 

consisting of vertical paths and horizontal rows. 

Each combination of path and row describes a unique 

185-by-170-kilometer rectangle of ground-surface 

area. The State of Massachusetts is represented by 

WRS paths 11, 12, and 13, and by rows 30 and 31 

(fig. 1); however, because adjacent paths overlap by as 

much as 40 percent, most of the State appears in paths 

12 and 13. If the images are shifted north along the two 

paths, then about 90 percent of the State can be imaged 

in only two scenes.

Use of TM imagery to assess lake quality and 

trophic state requires that predictive relations be developed between measured water-quality characteristics 

and the TM data. Ideally, these relations are based on 

measurements made at or close to the time of TM-data 

acquisition on a large number of lakes exhibiting the 

range of conditions likely to be encountered in the 

State. The 16-day Landsat-5 orbital repeat cycle provides about 10 opportunities for image acquisition 

between May 1 and September 30. However, the 

number of lakes that could be sampled during each flyover was limited by the small number of State and 

USGS personnel, boats, and equipment available for 

use in the study. The solution to this problem was to 

engage the Massachusetts Water Watch Partnership 

(MassWWP), which is affiliated with the University of 

Massachusetts and the Massachusetts Water Resources 

Research Center in Amherst, Mass., to recruit and train 

volunteers to sample lakes throughout the State.

A total of 76 individuals participated as volunteers during the three spring–summer sampling periods. Twenty-one volunteers were involved in the first 

sampling period (1996), 61 during the second sampling 

period (1997), and 39 during the third sampling period 

(1998). All volunteers were trained in lake-sampling 

and sample-processing techniques in a series of 

hands-on training sessions conducted each spring by 

MassWWP, MADEM, and USGS staff. Equipment 

was provided to the volunteers for measuring Secchi 

disk transparency, for collecting and processing 

water samples to be analyzed for color and phytoplankton-chlorophyll concentration, and for mapping 

distributions of macrophytes in the lakes.

The volunteers’ efforts greatly increased the 

amount of water-quality data collected concurrently 

with TM image acquisition. MADEM and USGS 

field personnel collected data at 94 stations on 65 lakes 

and volunteers collected data at 68 stations on 48 lakes. 

Sixteen of the lakes were sampled jointly by USGS and 

volunteers for quality assurance purposes. Volunteers 

were able to collect data each time the satellite was 

overhead from May through September. Most of the 

lakes sampled by MADEM and USGS could be sampled only once due to resource limitations. A list of the 

study lakes, their locations, and the numbers and kinds 

of water-quality measurements made during the three 

study periods is presented in table 6 (at back of report). 

In addition, distributions of floating, emergent, and 

submerged macrophytes were mapped in 49 lakes at 

least once during the study either by volunteers or by 

professional field personnel (table 2).

Selection of the study lakes was determined 

partly by the study requirement that the lakes be representative of lakes throughout the State and partly by 

other circumstances, including the affiliations and 

interests of the volunteers and the program requirements of the MADEM. Most of the volunteers live 

close to the lakes they sampled. The MADEM collected data primarily from lakes in State parks, forests, 

and reservations. Additional lakes were added to the 

list to ensure that the full range of trophic and waterquality conditions were represented in the data set. The 

lakes ranged in surface area from 4 to 696 ha with a 

median surface area of 36 ha. Seventy-five percent of 

the lakes had surface areas of 81 ha or less. Maximum 

depths of the lakes ranged from 2 to 30 m with a 

median of 7 m. Seventy-five percent of the lakes were 

less than 10 m deep.
Study Methods 5

Sampling and Analysis for 

Water-Quality Characteristics

Sampling stations were established over the 

deepest part of each study lake. For lakes with surface 

areas greater than about 81 ha, or with multiple basins, 

as many as six stations were established and monitored 

separately. Stations either were marked with a buoy or 

were located by aligning two pairs of landmarks on the 

shore spaced at a 90 degree angle relative to the station. 

Exact locations (latitude and longitude) of stations 

sampled by USGS field teams were determined by a 

global positioning system (GPS). All other stations 

were marked on appropriate USGS 1:25,000-scale 

topographic sheets and their locations determined with 

a digitizer.

Orbital schedules for Landsat-5 were obtained 

for each study period from the Earth Observation 

Satellite Company (EOSAT) in Lanham, Md. Sampling 

usually was scheduled for the morning of the flyover to 

coincide with the 9:45 a.m. equatorial crossing of the 

satellite, although data collected up to 24 hours before 

or after image acquisition were considered acceptable.

Field Observations

Upon arriving at a station, samplers completed a 

field form (fig. 2) in which they identified the lake and 

the station, and recorded maximum depth, percent 

cloud cover, barometric pressure, and air temperature. 

Surface-water temperature was measured either with 

a digital thermometer or with a standard alcohol thermometer. Secchi disk transparency was determined 

by lowering a standard 20-centimeter Secchi disk into 

the water and noting the exact depth at which it disappeared, then raising the disk and noting the depth at 

which it reappeared. The Secchi disk transparency was 

recorded as the mean of the two readings to the nearest 

0.1 m. Exact times of all field observations were 

recorded on the field sheet.

Phytoplankton-Chlorophyll 

Concentration

Water samples for phytoplankton-chlorophyll 

determinations were collected by hand in brown plastic 

1-liter bottles from a depth of about 0.25 m below the 

surface. The samples were returned on ice to shore 

where measured volumes were filtered onto 47 mm 

Watman GF/F glass-fiber filters using a maximum suction pressure of 0.5 atmospheres. The filters were 

folded in half and placed in a drying chamber where 

they were air dried at room temperature for 30 minutes. 

The dried filters were wrapped in aluminum foil and 

mailed overnight to the Environmental Analytical 

Laboratory at the University of Massachusetts, 

Amherst, for analysis. In the laboratory, the filters 

were ground in alkalized 90-percent acetone and analyzed spectrophotometrically for chlorophyll-a and 

phaeophytin-a concentrations (American Public Health 

Association and others, 1995). For the purposes of 

this study, the phytoplankton-chlorophyll concentration was considered to be the sum of the measured 

chlorophyll-a and phaeophytin-a concentrations.

Lake Color

Filtrate produced during field processing of 

the chlorophyll samples was transferred to clean, 

prelabeled glass or polyethylene bottles, which 

were shipped on ice overnight to the University of 

Massachusetts, Amherst, for analysis of color. Lake 

color was determined spectrophotometrically in a 

5-centimeter cell at a wavelength of 425 nm. The 

measured absorbance was converted to platinum-cobalt 

units (PCU) with a standard curve (American Public 

Health Association and others, 1995).
6 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

Figure 1. Locations of study lakes and Landsat-5 Worldwide

73°00 ́

42°30 ́

72°30 ́ 72°00 ́

42°00 ́

1

4

5

6 8

1 

10

9

3

2

7

11

12

CONNECTICUT

VERMONT

NEW HAMPSHIRE

NEW YORK

WRS PATH 13 ROW 31

WRS PATH 13 ROW 30

11009

33014

33019

12002 21083

21078 21005

33009

33017

33012

21011

21043 21044

32013

31004

31027

31044

31052

32055 36142

34051

34103

35035

35074

35017

35095

35090

81157

35041

36005

36173

36082

36155

36150

41016

41014

41008

41052 42005

42036

EXPLANATION

RIVER DRAINAGE BASINS

 1. Hudson 11. Nashua 18. North Coastal 22. Cape Cod

 2. Housatonic 12. Blackstone 19. Boston Harbor 23. Islands

 3. Deerfield 13. Merrimack a.Mystic 24. Buzzards Bay

 4. Westfield 14. Concord b.Neponset 25. Taunton

 5. Farmington a.Assabet c.Weymouth 26. Narragansett Bay

 6. Connecticut b.Concord and Wier and Mt. Hope

 7. Millers and Sudbury 20. Charles Bay Shore

 8. Chicopee 15. Shawsheen 21. South Coastal 27. Ten Mile

 9. Quinebaug 16. Parker a.North and

10. French 17. Ipswich South River

b.South Coastal Shore

BASIN BOUNDARY

SUBBASIN BOUNDARY

NOMINAL LOCATION OF SATELLITE 

 PATH OR ROW BOUNDARY. THE

 WORLDWIDE REFERENCE SYSTEM

 (WRS) NUMBERS ARE SHOWN 

 IN HELVETICA OBLIQUE TYPE

STUDY LAKE WITH 

 POND AND LAKE 

 IDENTIFICATION

 SYSTEM NUMBER

21043

0 40 80 MILES

0 40 80 KILOMETERS

46 ̊

72 ̊

70 ̊

68 ̊

ATLANTIC OCEAN

INDEX MAP OF

NEW ENGLAND STATES

44 ̊

42 ̊

MAINE

NEW YORK

CANADA

CANADA

VERMONT

NEW YORK CONNECTICUT

RHODE

ISLAND

MASSACHUSETTS

NEW 

HAMPSHIRE

USA

USA
Study Methods 7

11

14a

14b

20

13

21b

23

23

12

26

27

19b

18

21a

19a

16

9

17

15

25

24 22

19c

10

26

0 50 MILES

0 50 KILOMETERS

71°30 ́

71°00 ́

70°00 ́

70°30 ́

41°30 ́

70°30 ́

ATLANTIC OCEAN

Massachusetts

Bay

Nantucket

Sound

RHODE ISLAND

NEW HAMPSHIRE

81154

81153

81007

51027

51118

51024

51152

51179

51172

42064

96012

72008

72140

82061

82003

51112

82120

73062

62205

72125

82029

82058 82015

82042

HIGH ST. IMPOUNDMENT

82104

82119

82092 82011

82110

82118 82109

84001

91010

93014

71019 71047

71040

72017

72052

94007

95034

95119 95030

95054

95025

95151

96155

96302

96307

96218

96198 96333

62108

96039

96170

96091

WRS PATH 12 ROW 30

WRS PATH 12 ROW 31

WRS PATH 11 ROW 31

Reference System paths and rows for Massachusetts.
8 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

Dissolved Organic Carbon 

Concentration

Samples for DOC determinations were filtered 

through 0.45-μm-pore-size silver filters into baked 

brown-glass bottles using a stainless steel filtration 

system. The samples were then stored on ice prior to 

analysis. DOC determinations were carried out by the 

Environmental Analytical Laboratory at the University 

of Massachusetts, Amherst. Analysis of DOC was 

by wet oxidation with carbon dioxide detection by 

infrared spectroscopy (Fishman and Friedman, 1989).

Analytical Quality Assurance

Twelve sets of duplicate samples were collected 

at various sampling sites during the study and analyzed 

separately for DOC by the USGS National Water Quality Laboratory and the University of Massachusetts 

Environmental Analytical Laboratory. Differences 

between DOC determinations by the two laboratories 

ranged from 18 to 40 percent with a mean of 26 percent. Concentration differences among 12 duplicate 

determinations made by the Environmental Analytical 

Laboratory ranged from 0 to 18 percent with a mean of 

Table 2. Massachusetts lakes for which the distributions of floating, emergent, and submerged aquatic macrophytes were 

mapped in 1996, 1997, and 1998 for calibration of Landsat-5 Thematic Mapper imagery

[PALIS, Pond and Lake Identification System; X, mapped; blank space, not mapped; ---, no assigned code]

Lake name PALIS 

code

1996 1997 1998

Floating Emergent

Submerged Floating EmergentSubmerged Floating EmergentSubmerged

Althea Lake 84002 X X X

Ashmere lake 21005 X X X

Bare Hill Pond (USGS) 81007 X X X

Bare Hill Pond (USGS) 81007 X X

Bearse Pond 96012 X X

Big (Benton) Pond 31004 X X X

Buckley-Dunton Lake 32013 X X X

Charge Pond 95025 X X

Chebacco Lake 93014 X X X

Coes Reservoir 51024 X X X

Cook Pond 51027 X X

Curlew Pond 95034 X X X

Dudley Pond 82029 X X

East Brimfield Reservoir (East) 41014 X X X

East Brimfield Reservoir (West) 41014 X X X

Fearing Pond 95054 X X X

Goose Pond 21043 X X X

Greenwater Pond 21044 X X X

Heard Pond 82058 X X X

High Street Impoundment --- X X X

Horn Pond 71019 X X X X X X X X X

Mauserts Pond 11009 X X X

Merino Lake 42036 X X X

Metacomet Lake 34051 X X

Onota Lake 21078 X
Study Methods 9

7 percent. Color determinations made on the same sets 

of duplicates differed by 4 to 10 percent with a mean of 

6 percent.

Twelve sets of duplicate phytoplankton chlorophyll samples were analyzed during the study period 

by the University of Massachusetts Environmental 

Analytical Laboratory. The percent difference between 

duplicates ranged from 7 to 100 and the mean percent 

difference was 28. The highest percent differences 

were obtained from samples with extremely low 

chlorophyll concentrations (less than 1.0 μg/L).

Quality Assurance of 

Volunteer Data

Measurements of phytoplankton-chlorophyll 

concentration, Secchi disk transparency, color, and 

water temperature were made simultaneously at 26 stations on 16 lakes (table 3) by USGS and volunteer field 

teams to determine the reproducibility and reliability 

of the data. Measurements usually were made from 

the same boat. Samples were processed separately by 

each team and were shipped together to the analytical 

laboratory.

Table 2. Massachusetts lakes for which the distributions of floating, emergent, and submerged aquatic macrophytes were 

mapped in 1996, 1997, and 1998 for calibration of Landsat-5 Thematic Mapper imagery—Continued

Lake name PALIS 

code

1996 1997 1998

Floating Emergent

Submerged Floating EmergentSubmerged Floating EmergentSubmerged

Patch Reservoir 51118 X X X

Pequot Pond 32055 X X X

Pontoosuc Lake 21083

Puffer Pond (USGS) 82092 X X X

Puffer Pond 82092 X X X X

Rocky Pond 95119 X X X

Spy Pond 71040 X X

Sugden Reservoir 36150 X X X X X

Thompson Pond 36155 X X X X X X X X

Upper Spectacle Pond 31044 X X X

Waban Lake 72125 X X X X X X X X X

Walden Pond 82109 X X X

Wallum Lake (lower) 51172 X X

Warners Pond 82110 X X X

Webster Lake 42064 X X

Wequaquet Lake 96333 X X X

White Pond (Concord) 82118 X X X X X X

Whitehall Reservoir (NE) 82120 X X X

Whitehall Reservoir (NW) 82120 X X X

Whitehall Reservoir (SW) 82120 X X X

Winnekeag Lake 81157 X X

Winter Pond 71047 X X X X X X X X X

Winthrop Lake 72140 X X X X X X

York Lake 31052 X X X
10 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

USGS-MADEM-MassWWP Lake and Pond FIELD DATA

Name of Lake: PALIS Code:

Station No: Lat: Long:

Sampled By: Date:

Field Measurements

ns =not sampled Time of Measurement

Maximum Depth: meters/feet

Cloud Cover: % am/pm

Barometric Pressure: mmHg/inHg am/pm

Air Temperature: oC/oF am/pm

Surface Water Temperature: oC/oF am/pm

Secchi Disk Depth: meters/feet am/pm

Water Samples Collected

Date/Time of Sample:

Collection Preparation Shipping Vol. Filtered (L)

Chlorophyll:

Color:

DOC:

Remarks

Conversions

Multiply by To obtain

Feet 0.3048 Meters

Gallons 3.7853 Liters

Atmospheres 760 mmHg

Pounds/sq in 51.715 mmHg

Temperature can be converted to degrees Celsius (oC) from degrees Fahrenheit (oF) by the following equation:

oC = (oF-32) / 1.8

Figure 2. Example of field form used in volunteer field-data collection program.
Study Methods 11

Comparisons of measurement results obtained 

by the two sampling teams are presented in figures 3A

through 3B. There was good agreement between 

volunteer and USGS Secchi disk transparency determinations (fig. 3A). The percent difference between 

the two sets of measurements ranged from 0 to 24 

and the mean percent difference was 8. The two sets of 

phytoplankton-chlorophyll determinations were more 

variable (fig. 3B). Percent differences ranged from 7 to 

54 and the mean was 24 percent. At concentrations 

greater than 7 μg/L, the USGS samples consistently 

yielded 2–3 μg/L more chlorophyll than did the 

volunteer samples.

Agreement between color measurements made 

on USGS and volunteer water samples was not good 

(fig. 3C). Differences ranged from 2 to 200 percent. 

The mean percent difference was 72. The 

large differences may have resulted from inadequate 

cleaning of the volunteer sample containers. All USGS 

samples were submitted to the laboratory in baked 

glass bottles while volunteer samples were submitted 

in polyethylene bottles that had been used in a previous 

investigation.

Comparisons of water temperature measurements were reasonably good (fig. 3D), given the fact 

that different types of measuring devices were used. 

Percent differences between USGS and volunteer 

measurements ranges from 0 to 17 with a mean of 

3 percent.

Table 3. Lakes sampled by Massachusetts Water Watch Partnership volunteers concurrently with U.S. Geological Survey staff 

for chlorophyll concentration, Secchi disk transparency, color, and water temperature in 1997 and 1998

[Raw data available on the Internet at http://water.usgs.gov. PALIS, Pond and Lake Identification System; USGS, U.S. Geological Survey; X, water samples 

collected or measurements made concurrently; --, not measured]

Lake name Sampling

station

PALIS

code

Chlorophyll Secchi Color Water 

Temperature

Sampling 

date USGS WWP USGS WWP USGS WWP USGS WWP

Long Pond 1 62108 8-27-97 X X -- -- X X X X

Long Pond 2 62108 8-27-97 X X -- -- X X X X

Long Pond 3 62108 8-27-97 X X -- -- X X X X

Long Pond 4 62108 8-27-97 X X -- -- X X X X

Long Pond 5 62108 8-27-97 X X -- -- X X X X

Long Pond Deep

hole

62108 8-27-97 -- -- X X -- -- -- --

Lower Naukeag Lake 1 35041 8-04-98 X X X X -- -- X X

Onota Lake 1 21078 6-01-98 X X X X X X X X

Onota Lake 3 21078 6-01-98 X X X X X X X X

Pontoosuc Lake 1 21083 6-01-98 X X X X X X X X

Stearns Mill Pond 1 82104 7-12-98 X X -- -- X X X X

Upper Naukeag lake 1 35090 8-04-98 X X X X X X X X

Wallum Lake 1 51172 6-10-98 X X X X X X X X

Watatic Lake 1 35095 8-04-98 X X X X X X X X

Webster Lake 1 42064 6-10-98 X X X X X X X X

Webster Lake 2 42064 6-10-98 X X X X X X X X

White Pond (Concord) 1 82118 8-13-98 X X X X X X X X

White Pond (Hudson/Stow) 1 82119 7-12-98 X X X X X X X X

Whitins Reservoir 1 51179 6-10-98 X X X X X X X X

Whitins Reservoir 2 51179 6-10-98 X X X X X X X X

Willet Pond 1 73062 7-28-98 X X X X X X X X

Winnekeag Lake 1 81157 8-04-98 X X X X X X X X
12 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

0

1

2

3

4

5

6

7

8

012345678

SECCHI DISK TRANSPARENCY MEASURED

BY U.S. GEOLOGICAL SURVEY STAFF, IN METERS

SECCCHI DISK TRANSPARENCY MEASURED

 BY VOLUNTEERS, IN METERS

0

2

4

6

8

10

12

14

16

18

0 2 4 6 8 10 12 14 16 18

CHLOROPHYLL CONCENTRATIONS IN U.S. GEOLOGICAL

 SURVEY SAMPLES, IN MICROGRAMS PER LITER

CHLOROPHYLL CONCENTRATIONS IN VOLUNTEER

 SAMPLES, IN MICROGRAMS PER LITER

0

20

40

60

80

100

0 20 40 60 80 100

LAKE COLOR IN U.S. GEOLOGICAL SURVEY

SAMPLES, IN PLATINUM-COBALT UNITS

LAKE COLOR IN VLOUNTEER SAMPLES,

 IN PLATINUM-COBALT UNITS

A.

B.

C.

D.

18

19

20

21

22

23

24

25

26

27

28

18 19 20 21 22 23 24 25 26 27 28

WATER TEMPERATURE MEASURED BY U.S. GEOLOGICAL

 SURVEY STAFF, IN DEGREES CELSIUS

WATER TEMPERATURE MEASURED BY VOLUNTEERS,

 IN DEGREES CELSIUS

Figure 3. Relations between volunteer and U.S. Geological Survey staff measurements of (A) Secchi disk transparency; 

(B) phytoplankton-chlorophyll concentration; (C) color; and (D) surface-water temperature. (Dotted line is line of one-to-one 

correspondence of paired measurements.)
Thematic Mapper-Based Assessment of Water Quality and Trophic State 13

THEMATIC MAPPER-BASED 

ASSESSMENT OF WATER 

QUALITY AND TROPHIC STATE

At the end of each spring–summer study period, 

the available TM images were examined and ranked 

according to their degree of atmospheric interference 

due to haze and cloud cover, and the amount of lakewater-quality data available for correlation with pixel 

brightness values. On this basis, four scenes were purchased from the USGS Earth Resources Observation 

Systems (EROS) Data Center (EDC) in Sioux Falls, 

South Dakota. Scene identification codes and other 

descriptive information are presented in table 4. 

Each scene comprises picture elements (pixels) representing either 30-by-30 m (for visible and reflectedinfrared (IR) wave bands) or 120-by-120 m (for the 

thermal-IR wave band) ground-resolution cells. This 

study used data from visible TM wave bands 1 (TM1, 

0.45–0.52 μm), 2 (TM2, 0.52–0.60 μm), and 3 (TM3, 

0.63–0.69 μm), and reflected-IR wave band 4 (TM4, 

0.76-0.90 μm). Data for each pixel consist of digital 

numbers (DNs) ranging from 0 to 255 that represent 

the recorded intensity of reflected radiation in one of 

the wave bands. The scenes were radiometrically and 

geometrically corrected, rotated, and aligned to state 

plane coordinates by the EDC.

Lake-water-quality data collected within 24 

hours of acquisition of each TM scene were compiled 

and the brightness values for pixels corresponding to 

the station locations were extracted from the TM 

images. Brightness values for the three visible bands 

(TM1, TM2, and TM3) were then corrected for haze by 

regressing them against the corresponding values for 

the reflected-IR band (TM4). In the absence of scattering due to haze and other atmospheric irregularities, the 

intercepts of the regression lines should pass through 

the origin (Wilkie and Finn, 1996). In all four scenes, 

the regression lines intercepted the TM4 axes at some 

positive value, indicating the need for correction. The 

band was adjusted by the amount that the intercept 

shifted from the origin (Wilkie and Finn, 1996). The 

corrected TM values, plus the corresponding lakewater-quality data used in the analysis, are presented in 

table 7 (at back of report).

Secchi Disk Transparency and 

Phytoplankton-Chlorophyll 

Concentration

Phytoplankton-chlorophyll concentration was 

inversely correlated with Secchi disk transparency 

during all three sampling periods (fig. 4). The regression equations for the relations in 1996 and 1997 were 

similar, and indicated that 62 to 67 percent of the variability in Secchi disk transparency could be explained 

by the chlorophyll concentration. The unexplained 

variability is due to a combination of sampling and 

analytical errors, variations in lake color, and the presence of suspensoids other than phytoplankton algae 

(Goldman and Horne, 1983). 

The relation was shifted significantly in the 1998 

dataset. The slope of the regression line was similar to 

that calculated for the previous two years, but the yintercept was nearly doubled, so that chlorophyll concentrations associated with a given Secchi disk transparency increased by an average of 135 percent over 

the previous two years. The apparent increase may be 

related to a change in the analytical instrumentation 

used in the Environmental Analysis Laboratory that 

year.

Secchi disk transparency values and phytoplankton-chlorophyll data corresponding to the four TM 

scenes were analyzed using simple linear regression to 

develop relations that could be used to predict the 

water-quality characteristics from the TM data. 

Twenty-eight combinations of haze-corrected DNs for 

TM bands 1, 2, 3, and 4 were used as models in the 

analysis (table 5). The analytical approach was to plot 

Table 4. Landsat-5 Thematic Mapper scenes used to assess 

water-quality and trophic state of Massachusetts lakes

[EDC, Earth Resources Observation Systems (EROS) Data Center; WRS, 

Worldwide Reference System]

EDC scene

identification

Image

acquisition

date

WRS

path

WRS

row

LT5012031009620410 7-22-66 012 031.00000

LT5013030009720610 6-23-97 012 030.97174

LT5012030009723810 8-26-97 012 030.97000

LT5012031009816110 6-10-98 012 031.98000
14 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

-2.0

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

-1.5 -0.5 0.5 1.5 2.5 3.5

log(Chlorophyll) = -1.229 log(Secchi) + 2.670

R 2 = 0.621

n = 65, p < 0.0001

NATURAL LOGARITHM OF SECCHI DISK TRANSPARENCY

NATURAL LOGARITHM OF

CHLOROPHYLL CONCENTRATION

A. 1996

-2.0

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

-1.5 -0.5 0.5 1.5 2.5 3.5

log(Chlorophyll) = -1.345 log(Secchi) + 2.470

R 2 = 0.676

n = 156, p < 0.0001 2

B. 1997

NATURAL LOGARITHM OF 

 CHLOROPHYLL CONCENTRATION

NATURAL LOGARITHM OF SECCHI DISK TRANSPARENCY

the natural logarithms of the Secchi disk transparencies 

versus the phytoplankton-chlorophyll concentrations 

for a given scene to determine if the expected inverse 

relation existed between the two datasets. Obvious outliers were discarded and the remaining natural-logtransformed lake data were regressed against each of 

the TM models listed in table 5. No relations were 

observed that could be applied consistently to all the 

scenes and only a few of the models explained more 

than 60 percent of the variability in either the chlorophyll or the Secchi disk data.

The lack of any predictive relations between the 

TM data and phytoplankton-chlorophyll concentration 

or Secchi disk transparency was surprising given the 

long history of successful use of TM data to predict the 

water quality and trophic state of inland waters. Beginning with the work of Lathrop and Lillesand (1986), 

who used some of the earliest available TM data to 

assess chlorophyll concentration, Secchi disk transparency, turbidity, and the concentration of suspended 

solids in Green Bay and central Lake Michigan, 

researchers have reported on the ability of the TM to 

resolve differences in these parameters. More recently, 

Khorram and others (1991) and Baban (1993, 1997) 

reported successful correlation of lake chlorophyll concentration and Secchi disk transparency with TM data 

using the same methods and TM models as this study. 

The most important difference between these 

studies and the current one is the extremely low concentrations of phytoplankton chlorophyll typically 

found in Massachusetts lakes. Chlorophyll concentrations in the study lakes ranged from 0.5 to 84.5 μg/L. 

However, the mean chlorophyll concentration was only 

6.0 μg/L and the median concentration was 3.1 μg/L. 

Median chlorophyll concentrations in lakes studied by 

Lillesand and others (1983) generally were much 

higher, often ranging from 30 to more than 100 μg/L. 

Values of that magnitude were observed in fewer than 

5 of the 97 lakes included in this study. In addition, 

color of the study lakes ranged from less than 1 to 

547 PCU, with a mean of 91 and a median of 49 PCU. 

The wide variation in color may have introduced 

Figure 4. Relations between Secchi disk transparency and phytoplankton-chlorophyll concentration in Massachusetts lakes in 

(A) 1996; (B) 1997; and (C) 1998.
Thematic Mapper-Based Assessment of Water Quality and Trophic State 15

NATURAL LOGARITHM OF

 CHLOROPHYLL CONCENTRATION

-2.0

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

-1.5 -0.5 0.5 1.5 2.5 3.5

log(Chlorophyll) = -1.140 log(Secchi) + 3.936

R 2 = 0.537

n = 192, p < 0.0001 2

C. 1998

NATURAL LOGARITHM OF SECCHI DISK TRANSPARENCY

additional variability into the relations between 

chlorophyll concentration, Secchi disk transparency, and the TM data. In any case, it 

appears that eutrophication of Massachusetts 

lakes frequently is manifested more by proliferation of macrophytes than it is by growth of 

phytoplankton.

Lake Color and Dissolved 

Organic Carbon Concentration

Analysis of color and dissolved organic 

carbon (DOC) concentrations in water 

samples collected by USGS field teams in 

1996–98 indicated that color in Massachusetts 

lakes largely is due to DOC. The relation, 

shown in figure 5, was highly significant with 

R2 = 0.914. Samples collected by volunteers 

produced such variable results that no attempt 

was made to correlate them with TM data.

Figure 4. Relations between Secchi disk transparency and 

phytoplankton-chlorophyll concentration in Massachusetts lakes in 

(A) 1996; (B) 1997; and (C) 1998—Continued.

Table 5. Thematic mapper spectral bands and combinations of bands used as models to test for correlations with water-quality 

and trophic-state data for Massachusetts lakes

[TM, Thematic Mapper; TM1, TM band 1; TM2, TM band 2; TM3, TM band 3; TM4, TM band 4]

TM1 TM4 ( )2 TM2

TM3 ------------ TM4 TM3 –TM4 TM3 + -------------------------------

TM2 TM1 ln( ) TM1

TM2 ------------     ln TM2 TM1 –TM2 TM1 + -------------------------------

TM3 TM2 ln( ) TM1

TM3 ------------     ln TM2 TM3 –TM2 TM3 + -------------------------------

TM4 TM3 ln( ) TM2

TM3 ------------     ln TM4 TM3 –TM4 TM3 + -------------------------------     ln

( ) TM1 2 ln( ) TM4 TM1 TM2 +

2 ------------------------------- TM2 TM1 –TM2 TM1 + -------------------------------     ln

( ) TM2 2 TM1

TM2 ------------ TM1 TM3 +

2 ------------------------------- TM2 TM3 –TM2 TM3 + -------------------------------     ln

( ) TM3 2 TM1

TM3 ------------ TM2 TM3 +2 ------------------------------- TM2 TM3 –
16 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

0

5

10

15

20

25

30

0 100 200 300 400 500 600

COLOR, IN PLATINUM-COBALT UNITS

y = 0.0437 x + 1.7106

R2 = 0.914

n = 47, p < 0.0001

1996 1997 1998

DISSOLVED ORGANIC CARBON CONCENTRATION,

IN MILLIGRAMS PER LITER

THEMATIC MAPPER-BASED 

ASSESSMENT OF MACROPHYTE 

DISTRIBUTIONS

A method was developed for mapping distributions of macrophytes in lakes, ponds, and reservoirs 

using TM images processed with a geographic information system (GIS). The TM-based mapping procedure consists of manually mapping the distributions of 

aquatic macrophyte beds in 10 to 15 representative 

lakes and relating the digitized field-generated maps to 

a set of TM images of the lakes. These relations are 

then used to assign pixel-brightness values in the TM 

images to one of four vegetation-cover classes: open 

water (no macrophytes), moderately covered (up to 

50 percent) with floating or emergent macrophytes, 

densely covered (51–100 percent) with floating or 

emergent macrophytes, and covered to any extent with 

submerged macrophytes. These vegetation-cover class 

assignments can then be extended to any lake that is 

visible in the same TM scene.

Field-Mapping of Macrophyte 

Distributions

During 1996–98, distributions of floating, emergent, and submerged macrophytes were mapped in 44 

Massachusetts lakes, ponds, and reservoirs by USGS 

and MADEM staff and by volunteers affiliated with the 

MassWWP. Twenty-four sets of maps, 12 produced in 

1996 and 12 produced in 1997 from 19 of the lakes, 

were used to develop the TM-based mapping procedure. Excessive cloud cover during mid-to-late summer 

1998 precluded the use of maps produced in that year. 

The 19 lakes (table 2) are primarily in the eastern half 

of Massachusetts and represent the range of lake types 

in that part of the State. Surface areas of the lakes 

ranged from 7 to 233 ha with a median surface area of 

29 ha. Maximum depths ranged from 2 to 16 m with a 

median depth of 6 m.

Field-mapping was conducted in late summer 

after the macrophytes had reached their maximum densities but before they began to senesce in early autumn. 

For each lake, a set of blank maps (field maps) was produced with a 1:24,000-scale (USGS Digital Line 

Graphs) outline of the lakeshore overlain by a lattice of 

cells representing the 30-by-30-meter spatial resolution 

of the TM images. These field maps were used by 

observers to record the macrophyte distributions.

Aquatic macrophyte beds were identified and 

mapped separately as floating, emergent, or submerged 

growth forms. Floating macrophytes, such as water 

lilies (Nuphar sp., Nymphaea sp.) and water shield 

(Brasenia schreberi), commonly are found from the 

shoreline inward to depths of between 1 and 3 m. 

They may or may not be rooted in the sediments. 

Emergent macrophytes, such as cattails (Typha sp.), 

Figure 5. Relations between color and dissolved organic 

carbon concentration in Massachusetts lakes.
Thematic Mapper-Based Assessment of Macrophyte Distributions 17

grasses (Phragmites sp.), rushes (Juncus sp.), sedges 

(Scirpus sp.), arrow arum (Peltandra virginica), and 

pickerelweed (Pontederia cordata), typically are rooted 

and have foliage that extends out of the water. Emergent macrophytes generally are found along the edges 

of lakes in shallow water rarely exceeding 1 m in 

depth. Submerged macrophytes, such as fanwort 

(Cabomba sp.), various pondweeds (Potamogeton sp., 

Najas sp.), coontail (Ceratophyllum sp.), watermilfoil 

(Myriophyllum sp.), and bladderwort (Utricularia sp.), 

may occur from the shoreline across the entire lake 

bottom, but rarely extend beyond a depth of about 

10 m because of hydrostatic pressure and the limited 

penetration of underwater light. 

Mapping of floating and emergent macrophytes 

consisted of moving slowly along the shoreline in a 

boat and recording the locations of the macrophyte 

beds on the field maps. The lattice of 30-by-30 m cells 

superimposed on the lakeshore outline provided a scale 

by which observers could judge distances from the 

shore and accurately mark locations of the beds. The 

maps also indicated the positions of major landmarks 

such as roads, dams, and tributary streams, which 

provided additional reference points for mapping.

Macrophyte density within the mapped beds was 

estimated by the observers as (1) open water, (2) sparse 

(greater than 0 but less than 25 percent cover), (3) moderate (greater than 25 percent but less than 50 percent 

cover), (4) dense (greater than 50 percent but less than 

75 percent cover), (5) very dense (greater than 75 percent cover but less than 100 percent cover), or (6) complete (100 percent cover). Visual comparison of 

duplicate maps prepared at the same time by independent observers for three lakes in 1998 indicated that 

these density ranges were large enough to subsume 

minor differences or errors in the observers' density 

estimates.

Mapping of submerged macrophytes consisted 

of establishing multiple transects extending from shore 

to shore across the lakes. Transects usually were spaced 

about 120 m apart, except in the largest lakes, where 

they were spaced about 200 m apart. Landmarks represented on the maps were used as control points in locating the transects. Sampling points were then located at 

intervals of 60 to 120 m along each transect, either by 

direct measurement with a range finder or by estimating the distance and marking the position relative to the 

30-by-30-meter cells printed on the map. At each sampling point, a weighted two-sided rake, 0.46 m in 

length, was lowered on a line and dragged along the 

lake bottom for a distance of about 2 m. The amount of 

plant material retrieved on the rake relative to that 

retrieved in an area with visible submerged vegetation 

was used to estimate the areal coverage of submerged 

macrophytes at that point. A submerged-vegetation 

distribution map was then produced for each lake based 

on the estimated areal coverages.

Digitization and Processing of 

Field Maps

The hand-drawn field maps of macrophyte distributions were digitized by scoring the centroid of each 

30-by-30-meter cell as one of the six ranges of cover 

values, based on the mapped locations of the macrophyte beds. The scores for each map were then used to 

populate the cells of a raster grid corresponding to the 

lattice originally plotted on the map. The resulting 

grids were vectorized, clipped into the lake shoreline 

boundaries, and merged into a single data layer for 

each vegetation-cover type. The three data layers were 

then merged into a single data layer, maintaining the 

cover values for each vegetation-cover type.

Because the emergent vegetation was always 

close to the lake shorelines, and because it represented 

only a small part of the total covered area of most 

lakes, the cover values for floating and emergent 

vegetation types were combined into a single surface 

vegetation type. Also, the six original vegetationcover classes were reduced to four summary classes: 
18 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

(1) open water, (2) 1–50 percent floating-andemergent-vegetation cover, (3) 51–100 percent floating-and-emergent-vegetation cover, and (4) submerged 

vegetation at all densities (when not hidden by surface 

vegetation), when preliminary analyses indicated a 

potential bias in favor of open water. The result of 

combining vegetation-cover classes with small areal 

distributions into larger summary cover classes was 

to reduce the influence of the large areal extent of 

open water in many of the field maps on the final 

assignments of the TM pixel-brightness values.

Image Interpretation

Data in the TM scenes were processed into 

ARC/INFO by creating raster grids for TM2, TM3, and 

TM4 DNs. Grids for individual lakes were generated 

from these three TM-scene raster grids and rectified to 

the lake grids. The individual lake grids were then vectorized, clipped into the lakeshore boundaries, and 

merged into a single data layer for each of the three TM 

bands. The three data layers were then merged into a 

single data layer maintaining the DNs for each TM 

band. The effects of atmospheric haze were removed 

from the data for TM2 and TM3 by subtracting the 

smallest DNs for each wave band from all the brightness values for that wave band in the vector grid 

(Wilkie and Finn, 1996).

For each 30-by-30-meter cell in the data layer, a 

normalized difference vegetation index (NDVI; Lillesand and Kiefer, 1994) was calculated using the hazecorrected DNs for TM3 and TM4 as follows:

This data layer was merged with the data layer 

containing the four vegetation-cover classes. Inconsistencies in alignment of the 30-by-30-meter cells in the 

two data layers were corrected by bringing the combined data layer back into raster grid mode and using 

coordinates for each lake derived from the original TM 

images to rectify the cells in the vegetation-cover class 

data layer. The combined data layer was vectorized and 

30-by-30-meter cells falling entirely within lakeshore 

boundaries were given a new attribute that differentiated them from the smaller cells that intersected the 

shorelines. Cells associated with islands in the lakes 

were similarly differentiated. 

Cells that did not intersect with lake shorelines 

were grouped according to their NDVI values. For each 

NDVI value, the total areas were determined for the 

two surface vegetation-cover classes (1–50 percent and 

51–100 percent floating and emergent) and for a hybrid 

vegetation-cover class consisting of open water and 

submerged vegetation. The vegetation-cover class 

comprising the largest total area of the three was then 

assigned to that NDVI value. In this way, each NDVI 

value in the dataset was associated with one of the 

three surface-vegetation cover classes or with open 

water. These associations were then used to assign 

vegetations cover classes to cells that intersected the 

lake shorelines.

The vegetation-cover class assignments for each 

cell were then examined to determine if any should be 

changed based on the NDVI values of adjacent cells. 

If a given NDVI value predominated in the eight-cell 

neighborhood surrounding a cell, then that NDVI value 

was added to the cell as an alternative value. Next, all 

cells with that combination of NDVI value and alternative value were selected and assigned the vegetationcover class most frequently associated with the combination. In this way, some inconsistent assignments arising from the limited spatial resolution of the TM data 

were removed.

To determine areas of submerged vegetation, all 

cells that were not assigned a surface-vegetation cover 

class in the NDVI analysis were isolated, and a ratio 

index was calculated by dividing the haze-corrected 

DNs for TM2 by those for TM3. The steps performed 

to assign NDVI values were then repeated on these isolated cells, the one difference being that the cells digitized as submerged vegetation were maintained and 

included as an option for assignment.

NDVI TM4 – TM3

TM4 + TM3 = ------------------------------
Thematic Mapper-Based Assessment of Macrophyte Distributions 19

Observed Versus Predicted 

Macrophyte Distributions

Satellite images from July 22, 1996, and August 

26, 1997, were used, together with mapped distributions of 1996 and 1997 aquatic-vegetation cover in 19 

study lakes, to develop predictive models relating the 

satellite data to the observed macrophyte distributions. 

Relations developed for the 1996 data were used to predict distributions in the original 1996 lakes, and relations developed for the 1997 data were used to predict 

distributions in the original 1997 lakes. Finally, the 

relations developed for the 1997 data were tested on the 

1996 satellite scene and the predicted results compared 

with observed 1996 macrophyte distributions.

1996 Predictions Based on 

1996 Interpretations

Figure 6 shows the relations between observed 

(field mapped in summer 1996) and predicted (interpreted from 1996 Thematic Mapper data) aquaticmacrophyte cover areas in twelve 1996 study lakes 

for each of the four vegetation-cover classes. For 

open water, the root-mean-squared-error (RMSE) of 

the prediction was 3.6 ha for observed cover areas 

ranging from 0 to 39.7 ha. Predicted open-water 

cover areas tended to be smaller than observed openwater cover areas. This result can been observed in 

figure 7, which shows maps of observed and predicted 

aquatic-vegetation cover for Whitehall Reservoir, in 

Hopkinton, Mass. Agreement between observed and 

predicted cover areas for the other three vegetationcover classes was very good, with RMSE ranging from 

1.3 ha for 51–100 percent floating-and-emergent-vegetation cover to 5.7 ha for submerged vegetation cover 

(fig. 6).

1997 Predictions Based on 

1997 Interpretations

The TM-based maps developed from the 1997 

data set did not match the observed 1997 maps as 

closely as did those developed from the 1996 data set. 

The TM-based mapping procedure predicted larger 

amounts of open-water cover area and smaller amounts 

of submerged vegetation cover area than were observed 

(fig. 8), although the RMSE values were similar to 

those exhibited by the 1996 relations (6.3 ha for openwater cover and 5.3 ha for submerged vegetation 

cover). Lakes in the 1997 data set tended to have larger 

observed open-water cover areas than those in the 1996 

data set (fig. 9). The median observed open-water cover 

area was 11.9 ha in the 1997 data set and 8.2 ha in the 

1996 data set. Similarly, observed cover areas for submerged vegetation were much smaller in the 1997 data 

set (median = 0.7 ha) than they were in the 1996 data 

set (median = 5.8 ha).

Agreement between observed and predicted 

cover areas was better for the two floating-andemergent-vegetation cover classes (the RMSE was 

2.5 ha for the 1–50 percent floating-and-emergent 

cover class and 1.1 ha for the 51–100 percent floatingand-emergent cover class) than it was for the open 

water and submerged-vegetation cover classes (fig. 8). 

Because most of the observed areas for these classes 

were very small (1.0 to 6.0 ha), however, the errors are 

significant.

1996 Predictions Based on 

1997 Interpretations

An attempt to predict vegetation-cover class 

areas in the 1996 study lakes based on interpretations 

developed from the 1997 data set was unsuccessful. 

Large areas of submerged or floating and emergent 

vegetation were interpreted as open water for many 

lakes. Consequently, predicted cover areas for submerged vegetation and the 1–50 percent floating-andemergent-vegetation class were smaller than the 

corresponding observed cover areas and had correspondingly large RMSE values [27.7 and 11.4 ha, 

respectively (fig. 10)]. The only exceptions were the 

areas predicted for the 51–100 percent floating-andemergent-vegetation cover class, which produced a 

RMSE of 1.1 ha over observed (1996) cover values 

ranging from 0 to 26.8 ha. The large discrepancy in 

predicted versus observed areas of submerged vegetation can be seen in figure 11, which maps predicted and 

observed aquatic vegetation cover for East Brimfield 

Reservoir in Brimfield and Sturbridge, Mass.
20 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

0

10

20

30

40

50

0 10 20 30 40 50

RMSE = 3.6 ha

Open water

0

25

50

75

100

125

150

0 25 50 75 100 125 150

RMSE = 5.7 ha

 Submerged vegetation

0

10

20

30

40

50

60

0 10 20 30 40 50 60

RMSE = 3.4 ha

1-50% Floating and

emergent vegetation

0

10

20

30

40

0 10 20 30 40

RMSE = 1.3 ha

51-100% Floating and

emergent vegetation

1996 OBSERVED COVER, IN HECTARES

1996 PREDICTED COVER, IN HECTARES

Figure 6. Observed (field-mapped in summer 1996) and predicted (interpreted from July 1996 

Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in 12 

Massachusetts lakes.
Thematic Mapper-Based Assessment of Macrophyte Distributions 21

EXPLANATION

0 PERCENT VEGETATION (OPEN WATER)1 TO 50 PERCENT SURFACE VEGETATION51 TO 100 PERCENT SURFACE VEGETATIONSUBMERGED VEGETATION

OBSERVED VEGETATION 

WHITEHALL RESERVOIR 

30 METER BY 30 METER CELLS 30 METER BY 30 METER CELLS

PREDICTED VEGETATION 

WHITEHALL RESERVOIR 

LOCATION MAP

73 ̊00'

42 ̊30'

42 ̊00'

41 ̊30'

72 ̊00'

71 ̊00'

70 ̊00' ATLANTIC OCEAN Massachusetts Bay

Nantucket

Sound

50 MILES 0

50 KILOMETERS 0

Figure 7. Observed (field-mapped in summer 1996) and predicted (interpreted from July 1996 Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in Whitehall Reservoir, Hopkinton, Massachusetts.
22 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

0

10

20

30

40

50

0 10 20 30 40 50

0

2

4

6

8

10

12

14

16

0 2 4 6 8 10 12 14 16

0

2

4

6

8

10

12

14

0 2 4 6 8 10 12 14

0

5

10

15

20

0 5 10 15 20

RMSE = 6.3 ha

RMSE = 2.5 ha

RMSE = 5.3 ha

RMSE = 1.1 ha

Open water Submerged vegetation

1-50% Floating and

 emergent vegetation

51-100% Floating and

emergent vegetation

OBSERVED COVER, IN HECTARES

PREDICTED COVER, IN HECTARES

Figure 8. Observed (field-mapped in summer 1997) and predicted (interpreted from August 1997 

Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in 12 

Massachusetts lakes.
Thematic Mapper-Based Assessment of Macrophyte Distributions 23

OBSERVED VEGETATION 

THOMPSON POND

30 METER BY 30 METER CELLS 30 METER BY 30 METER CELLS

PREDICTED VEGETATION 

THOMPSON POND

EXPLANATION

0 PERCENT VEGETATION (OPEN WATER)1 TO 50 PERCENT SURFACE VEGETATION51 TO 100 PERCENT SURFACE VEGETATIONSUBMERGED VEGETATION

LOCATION MAP

73 ̊00'

42 ̊30'

42 ̊00'

41 ̊30'

72 ̊00'

71 ̊00'

70 ̊00' ATLANTIC OCEAN Massachusetts Bay

Nantucket

Sound

50 MILES 0

50 KILOMETERS 0

Figure 9. Observed (field-mapped in summer 1997) and predicted (interpreted from August 1997 Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in Thompson Pond, Spencer, Massachusetts.
24 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

0

25

50

75

100

125

150

0 25 50 75 100 125 150

RMSE = 39.7 ha

Open water

0

25

50

75

100

125

150

0 25 50 75 100 125 150

RMSE = 27.7 ha

Submerged vegetation

0

10

20

30

40

50

60

0 10 20 30 40 50 60

RMSE = 11.4 ha

1-50% Floating and

emergent vegetation

0

5

10

15

20

25

30

0 5 10 15 20 25 30

RMSE = 1.1 ha

51-100% Floating and

emergent vegetation

OBSERVED COVER, IN HECTARES

PREDICTED COVER, IN HECTARES

Figure 10. Observed (field-mapped in summer 1996) and predicted (interpreted from August 1997 

Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in 12 

Massachusetts lakes.
Thematic Mapper-Based Assessment of Macrophyte Distributions 25

OBSERVED VEGETATION 

EAST BRIMFIELD RESERVOIR

30 METER BY 30 METER CELLS 30 METER BY 30 METER CELLS

PREDICTED VEGETATION 

EAST BRIMFIELD RESERVOIR

EXPLANATION

0 PERCENT VEGETATION (OPEN WATER)1 TO 50 PERCENT SURFACE VEGETATION51 TO 100 PERCENT SURFACE VEGETATIONSUBMERGED VEGETATION

LOCATION MAP

73 ̊00'

42 ̊30'

42 ̊00'

41 ̊30'

72 ̊00'

71 ̊00'

70 ̊00' ATLANTIC OCEAN Massachusetts Bay

Nantucket

Sound

50 MILES 0

50 KILOMETERS 0

Figure 11. Observed (field-mapped in summer 1996) and predicted (interpreted from August 1997 Thematic Mapper data) areal coverages of four aquatic macrophyte cover classes coverages in East Brimfield Reservoir, Brimfield and Sturbridge, Massachusetts.
26 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes

SUMMARY AND 

CONCLUSIONS

During the spring and summer of 1996, 1997, 

and 1998, measurements of phytoplankton- chlorophyll 

concentration, Secchi disk transparency, and color 

were made at 97 Massachusetts lakes within 24 hours 

of Landsat Thematic Mapper (TM) imaging of the 

lakes in an effort to use the TM imagery to assess 

lake-water quality. Spatial distribution of floating, 

emergent, and submerged macrophytes were mapped 

in 49 of the lakes at least once during the three-year 

period. The maps were digitized and used to assign 

pixels in the TM images to one of four vegetation 

cover classes—open water, 1–50 percent floating-andemergent-vegetation cover, 51–100 percent floatingand-emergent-vegetation cover, and submerged vegetation at any density. Concurrent data collection and sampling by USGS and trained volunteer field teams 

resulted in similar chlorophyll determinations, Secchi 

disk readings, and temperature measurements, but 

color determinations were highly variable, possibly 

due to contamination of sample bottles issued to the 

volunteers.

Attempts to develop predictive relations between 

phytoplankton-chlorophyll concentration, Secchi disk 

transparency, lake color, dissolved oxygen concentration (DOC), and various combinations of TM band 1, 

2, 3, and 4 digital numbers (DNs) were unsuccessful. 

The poor relations were primarily the result of the 

extremely low chlorophyll concentrations (median = 

3.1 μg/L) in the lakes studied, and also because of 

the highly variable DOC concentrations as indicated 

by color values ranging from less than 1 to 547 

platinum-cobalt units (PCU).

Predictive relations were developed between 

Secchi disk transparency and phytoplanktonchlorophyll concentration and between color and 

DOC concentration. Phytoplankton-chlorophyll concentration was inversely correlated with Secchi disk 

transparency during all three sampling periods. The 

regression equations for the relations in 1996 and 1997 

were similar and showed that 62 to 67 percent of the 

variability in chlorophyll concentration could be 

explained by the Secchi disk transparency. Analysis of 

color and DOC concentrations in water samples collected by USGS field teams in 1996–98 indicated that 

most of the color in Massachusetts lakes is due to 

DOC.

Areas of open-water, submerged vegetation, and 

two surface-vegetation-cover classes predicted from 

TM images acquired in the summer of 1996 closely 

matched the areas observed in a set of field observations. Agreement between observed and predicted 1996 

submerged-macrophyte cover areas was at least as 

good as the 56- to 70-percent accuracy reported for 

mapping studies using visual interpretations of aerial 

photographs (Schloesser and others, 1987); however, 

the same analysis applied to a set of data acquired in 

the summer of 1997 resulted in somewhat less reliable 

predictions, and an attempt to predict 1996 vegetation 

cover areas using the relations developed in the 1997 

analysis was unsuccessful.

Differences in the predictive power of the two 

data sets appear to stem from differences in the relative 

sizes of the vegetation-cover areas used in the initial 

calibration of the NDVI values. The ranges of observed 

areas of the four vegetation-cover classes were similar 

in the 1996 data set. By contrast, open water predominated in lakes forming the 1997 data set, and the other 

vegetation-cover classes had much smaller and more 

variable ranges. Both the field-mapping and the TMimaging processes are subject to error. Locations of the 

macrophyte beds indicated on the field maps cannot be 

exact, and the TM images are limited by the 30-by-30-

meter ground resolution of the instrument. Under these 

conditions, a preponderance of one type of vegetation 

cover class in the calibration data set is likely to result 

in more assignments of NDVI values to that cover 

class, simply because locational errors involving that 

cover class will tend to occur more frequently. It is also 

possible that the failure of the method to accurately 

predict the 1996 macrophyte distributions based on 

interpretations of 1997 data was due in part to this 

problem.

Ideally, the method should be applied to a set of 

mapped lakes and then tested on a second set not used 

in the initial calibration. This was not possible given 

the limited number of field maps available in the two 

data sets and the need for equal areal representation of 
References Cited 27

vegetation-cover classes. By careful selection of the 

initial set of lakes to ensure adequate representation of 

vegetation cover, it may be possible to use fewer lakes 

in the calibration process without sacrificing predictive 

power. The calibration data set also could be improved 

by using a global-positioning system to accurately 

locate and map the aquatic macrophyte beds.

REFERENCES CITED

American Public Health Association, American Water Works 

Association, and Water Pollution Control Commission, 

1995, Standard methods for the examination of water 

and wastewater (19th ed.): Washington, D.C., APHA, 

[variously paginated].

Baban, S.M.J., 1993, Detecting water quality parameters in 

the Norfolk Broads, U.K., using Landsat imagery: 

International Journal of Remote Sensing, vol. 14, no. 7, 

p. 1247–1267.

_____1997, Environmental monitoring of estuaries; 

estimating and mapping various environmental 

indicators in Breydon Water Estuary, U.K., using 

Landsat TM imagery: Estuarine, Coastal, and Shelf 

Science, vol. 44, p. 589–598.

Canfield, D.E., Jr., Langland, K.A., Maceina, M.J., Haller, 

W.T., and Shireman, J.V., 1983, Trophic state 

classification of lakes with aquatic macrophytes: 

Canadian Journal of Fisheries and Aquatic Sciences, 

v. 40, p. 1713–1718.

Fishman, M.J., and Friedman, L.C., eds., 1989, Methods for 

determination of inorganic substances in water and 

fluvial sediments: U.S. Geological Survey Techniques 

of Water-Resources Investigations, book 5, chap. A1, 

545 p.

Goldman, C.R., and Horne, A.J., 1983, Limnology: New 

York, McGraw-Hill Book Co., 464 p.

Khorram, Siamak, Cheshire, Heather, Geraci, Alberto L., 

and LaRosa, Guido, 1991, Water quality mapping of 

Agusta Bay, Italy, from Landsat-TM data: International 

Journal of Remote Sensing, vol. 12, no. 4, p. 803–808.

Lathrop, R.G., Jr., and Lillesand, T.M., 1986, Use of 

Thematic Mapper data to assess water quality in Green 

Bay and central Lake Michigan: Photogrammetric 

Engineering and Remote Sensing, vol. 52, no. 5, 

p. 671–680.

Lillesand, T.M., Johnson, W.L., Deuell, R.L., Lindstrom, 

O.M., and Meisner, D.E., 1983, Use of Landsat 

data to predict trophic state of Minnesota lakes: 

Photogrammetric Engineering and Remote Sensing, 

v. 49, no. 2, p. 219–229.

Lillesand, T.M., and Kiefer, R.W., 1994, Remote sensing and 

image interpretation (3rd ed.): New York, John Wiley 

and Sons, Inc., 750 p.

Massachusetts Water Resources Commission, 1994, Policy 

on lake and pond management: Boston, Massachusetts 

Water Resources Commission, Division of Water 

Resources, 5 p.

Raitala, J.T., 1986, Satellite data in aquatic research—Some 

ideas for future studies: Symposium on Remote Sensing 

for Resources Development and Environmental 

Management, Enschede, August, 1986, p. 755–758.

Scarpace, F.L., Holmquist, K.W., and Fisher, L.T., 1979, 

Landsat analysis of lake quality: Photogrammetric 

Engineering and Remote Sensing, v. 45, no. 5, p. 623–

633.

Schloesser, D.W., Manny, B.A., Brown, C.L., and Jaworski, 

E., 1987, Use of low-altitude aerial photography to 

identify submersed macrophytes, in Color Aerial 

Photography in the Plant Sciences and Related Fields: 

Ann Arbor, University of Michigan, Proceedings of the 

10th Biennial Workshop, 1984, p. 19–28.

Shimoda, H., Etaya, M., Sakata, T., Goda, L., and Stelczer, 

K., 1986, Water quality monitoring of Lake Balaton 

using LANDSAT MSS data: Symposium on Remote 

Sensing for Resources Development and Environmental 

Management, Enschede, August, 1986, p. 765–770.

U.S. Environmental Protection Agency, 1995, The state of 

the New England environment, 1970–1995: Boston, 

Mass., U.S. Environmental Protection Agency–New 

England, Office of External Programs, 20 p.

Verdin, J.P., 1985, Monitoring water quality conditions 

in a large western reservoir with Landsat imagery: 

Photogrammetric Engineering and Remote Sensing, 

v. 51, p. 343–353.

Wilkie, D.S., and Finn, J.T., 1996, Remote sensing imagery 

for natural resources monitoring—A guide for first-time 

users: New York, Columbia University Press, 295 p.

Witzig, A.S., and Whitehurst, C.A., 1981, Current use and 

technology of LANDSAT MSS data for lake trophic 

classification: Water Resources Bulletin, vol. 17, no. 6, 

p. 962–970.
Tables 6 and 7
Table 6 31

Table 6. Massachusetts lakes sampled in 1996, 1997, and 1998, and numbers of measurements of water-quality characteristics made for calibration of Landsat-5 Thematic Mapper imagery—Continued

Lake name Sampling station PALIS code Town/city Drainage basin

Sampled in: Total number of measurements

1996 1997 1998 Chloro- phyll DOC Color Secchi Temper- ature

Lakes Sampled by Massachusetts Water Watch Partnership Volunteers

Bearse Pond 16 96012 Barnstable Cape Cod X X 8 -- 3 3 7Billington Sea 1 94007 Plymouth South Shore Coastal X 1 -- 2 3 3Billington Sea 3 94007 Plymouth South Shore Coastal X 1 -- 2 3 3Billington Sea 6 94007 Plymouth South Shore Coastal X 1 -- 2 3 3Boon Lake LBA1 82011 Stow/Hudson Assabet (Concord) X X X 6 -- 3 3 5Boon Lake LBA2 82011 Stow/Hudson Assabet (Concord) X X X 6 -- 1 3 3Boon Lake LBA3 82011 Stow/Hudson Assabet (Concord) X 2 -- -- -- --Buffumville Reservoir 1 42005 Oxford/Charlton French X 3 -- 3 3 3Carding Mill Pond 1 82015 Sudbury Sudbury (Concord) X X 2 -- 2 3 3Chabacco Lake 1 93014 Hamilton/Essex North Shore Coastal X -- -- -- 1 3Chandler Pond 1 72017 Boston Charles X X 5 -- 5 6 6Dudley Pond 1 82029 Wayland Sudbury (Concord) X 2 -- 4 4 4Fort Meadow Reservoir 1 82042 Marlborough/Hudson Assabet (Concord) X X 5 -- -- 1 2George Lake (Wales Pond) 1 41016 Wales Quinebaug X -- -- -- 1 1Goose Pond 1 21043 Lee/Tyringham Housatonic X X 10 -- 4 8 7Heard Pond 1 82058 Wayland Sudbury (Concord) X X X 10 -- 12 12 11High St. Impoundment 1 -- Maynard/Acton Assabet (Concord) X X 5 -- 4 5 5Horn Pond 1 71019 Woburn Mystic X X X 9 -- 8 10 10Jenkins Pond 1 96155 Falmouth Cape Cod X 4 -- 4 4 4Jenkins Pond 2 96155 Falmouth Cape Cod X 1 -- 1 1 1Long Pond 1 62108 Freetown/Lakeville Taunton X 5 -- 5 -- 6Long Pond 2 62108 Freetown/Lakeville Taunton X 5 -- 4 -- 6Long Pond 3 62108 Freetown/Lakeville Taunton X 5 -- 3 -- 6Long Pond 4 62108 Freetown/Lakeville Taunton X 5 -- 5 -- 6Long Pond 5 62108 Freetown/Lakeville Taunton X 5 -- 3 -- 6

Table 6. Massachusetts lakes sampled in 1996, 1997, and 1998, and numbers of measurements of water-quality characteristics made for calibration of Landsat-5 Thematic Mapper imagery[PALIS Code: PALIS, Pond and Lake Identification System. Total number of measurements: Chlorophyll, sum of chlorophyll-a and phaeophytin-a concentrations; DOC, dissolved organic carbon 

concentration; Secchi, Secchi disk transparency; Temperature, surface-water temperature. MADEM, Massachusetts Department of Environmental Management; S.F., State Forest; S.P., State Park; S.R., State Reservation; USGS, U.S. Geological Survey; --, not measured or unknown]
32 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes Lakes Sampled by Massachusetts Water Watch Partnership Volunteers—Continued Long Pond Deep hole 62108 Freetown/Lakeville Taunton X -- -- -- 1 1 Lower Naukeag Lake 1 35041 Ashburnham Millers X X 10 -- 8 10 10 Maspenock Lake Deep end 51112 Hopkinton/Milford Blackstone X X 11 -- 10 9 9 Maspenock Lake Basin 51112 Hopkinton/Milford Blackstone X X 11 -- 9 8 8 Merino Lake 1 42036 Dudley French X 13 -- 9 7 7 Metacomet Lake Deep hole 34051 Belchertown Connecticut X X X 11 -- 11 11 11 Middle Pond 1 96198 Barnstable Cape Cod X X 6 -- 4 8 8 Mystic Lake 1 96218 Barnstable Barnstable X 2 -- 3 3 4 Onota Lake 1 21078 Pittsfield Housatonic X X X 12 -- 11 18 15 Onota Lake 2 21078 Pittsfield Housatonic X X X 5 -- 4 11 8 Onota Lake 3 21078 Pittsfield Housatonic X 8 -- 6 7 7 Pontoosuc Lake 1 21083 Pittsfield/Lanesboro Housatonic X X X 11 -- 9 18 14 Table 6. Puffer Pond 1 82092 Sudbury/Maynard Sudbury (Concord) X X X 14 -- 14 12 12 Singletary Lake 1 51152 Sutton/Milbury Blackstone X X 2 -- 2 2 3 Singletary Lake 2 51152 Sutton/Milbury Blackstone X 2 -- 2 2 2 Snake Pond 1 96302 Sandwich Cape Cod X X 7 -- 4 7 7 Spectacle Pond (Wilbraham) Beach 36142 Wilbraham Chicopee X 1 -- -- -- -- Spectacle Pond (Wilbraham) Middle 36142 Wilbraham Chicopee X 2 -- -- 1 1 Spectacle Pond (Sandwich) 1 96307 Sandwich Cape Cod X X 6 -- 2 2 6 Spy Pond South 71040 Arlington Mystic X X 3 -- 3 5 1 Spy Pond North 71040 Arlington Mystic X X 4 -- 4 4 8 Stearns Mill Pond 1 82104 Sudbury Sudbury (Concord) X X X 14 -- 15 8 12 Sugden Reservoir 1 36150 Spencer Chicopee X X 12 -- 11 13 13 Thompson Pond 1 36155 Spencer Chicopee X X X 16 -- 10 19 21 Thompson Pond 6 36155 Spencer Chicopee X -- -- 1 1 1 Upper Naukeag Lake 1 35090 Ashburnham Millers X X 10 -- 9 11 11 Waban Lake 2 72125 Wellesly Charles X X X 13 -- 11 13 13 Wallum Lake 1 51172 Douglas Blackstone X X X 19 -- 14 15 10 Warners Pond 1 82110 Concord Assabet (Concord) X X 5 -- 5 5 5 Watatic Lake 1 35095 Ashburnham/Ashby Millers X X 10 -- 8 11 11 Massachusetts lakes sampled in 1996, 1997, and 1998, and numbers of measurements of water-quality characteristics made for calibration of Landsat-5 Thematic Mapper imagery

—Continued

Lake name Sampling station PALIS code Town/city Drainage basin

Sampled in: Total number of measurements

1996 1997 1998 Chloro- phyll DOC Color Secchi Temper- ature
Table 6 33

Lakes Sampled by Massachusetts Water Watch Partnership Volunteers—Continued

Webster Lake 1 42064 Webster French X X X 19 -- 19 16 10Webster Lake 2 42064 Webster French X X X 18 -- 18 14 15Wequaquet Lake 14 96333 Barnstable Cape Cod X X 9 -- 2 19 9Wequaquet Lake 15 96333 Barnstable Cape Cod X X 7 -- 2 7 7White Pond (Concord) 1 82118 Concord Sudbury (Concord) X X X 11 -- 12 12 12White Pond (Hudson/Stow) 1 82119 Hudson/Stow Assabet (Concord) X X X 10 -- 11 7 10Whitins Reservoir 1 51179 Douglas Blackstone X X X 15 -- 13 12 9Whitins Reservoir 2 51179 Douglas Blackstone X X 12 -- 11 10 11Willet Pond 1 73062 Walpole/Norwood/Westwood Neponset X X 3 -- 3 3 3Winnekeag lake 1 81157 Ashburnham Nashua X X 10 -- 10 11 11Winter Pond 1 71047 Winchester Mystic X X X 10 -- 10 10 9Winthrop Lake Deep hole 72140 Holliston Charles X X 4 -- 5 5 6Wyola Lake Center 34103 Shutesbury Connecticut X X X 12 -- 10 12 10

Lakes Sampled by USGS and MADEM Staff

Althea Lake 1 84001 Lowel, Dracut, Tyngsboro 

S.F.

Merrimack X 2 -- 1 1 1

Ashland Reservoir 1 82003 Ashland S.P. Sudbury (Concord) X 1 2 1 1 1Ashmere Lake 1 21005 Pittsfield S.F. Housatonic X 1 -- 1 1 1

Ashmere Lake 2 21005 Pittsfield S.F. Housatonic X 1 -- 1 1 1

Asnacomet Pond 1 36005 Hubbardston Chicopee X 1 1 1 1 1Babson Farm Quarry 1 -- Halibut Point S.P. North Shore Coastal X -- -- 1 1 1Benedict Pond Deep hole 21011 Beartown S.F. Housatonic X 2 -- 1 1 --Berry Pond Deep hole 12002 Pittsfield S.F. Kinderhook X 1 -- 1 1 1

Big (Benton) Pond 1 31004 Otis S.F. Farmington X 1 -- 1 1 1Billington Sea 1 94007 Plymouth South Shore Coastal X 1 1 1 1 1Billington Sea 3 94007 Plymouth South Shore Coastal X 1 1 1 1 1Billington Sea 6 94007 Plymouth South Shore Coastal X 1 1 1 1 1Box Pond 1 72008 Bellingham/Mendon Charles X 1 -- 1 1 1Buckley-Dunton lake 1 32013 October Mt. S.F. Westfield X 1 -- 1 1 1

Buckley-Dunton Lake Deep hole 32013 October Mountian S.F. Westfield X 1 -- 1 1 1

Table 6. Massachusetts lakes sampled in 1996, 1997, and 1998, and numbers of measurements of water-quality characteristics made for calibration of Landsat-5 

Thematic Mapper imagery—Continued

Lake name Sampling station PALIS code Town/city Drainage basin

Sampled in: Total number of measurements

1996 1997 1998 Chloro- phyll DOC Color Secchi Temper- ature
34 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes Lakes Sampled by USGS and MADEM Staff—Continued Buckley-Dunton Lake Inlet 32013 October Mountian S.F. Westfield X 1 -- 1 1 1 Cedar Pond 1 41008 Sturbridge Quinebaug X 1 1 1 1 1 Charge Pond 1 95025 Myles Standish S.F. Buzzards Bay X 1 -- 1 1 1 Cliff Pond 1 96039 Nickerson S.P. Cape Cod X 1 -- 1 1 1 College Pond 1 95030 Myles Standish S.F. Buzzards Bay X 1 1 1 1 1 Curlew Pond 1 95034 Myles Standish S.F. Buzzards Bay X 1 -- 1 1 1 Denison Lake 1 35017 Otter River S.F. Millers X 1 4 1 1 1 East Brimfield Reservoir 1 41014 Streeter Point Rec. Area Quinebaug X 1 1 1 1 1 East Brimfield Reservoir 2 41014 Streeter Point Rec. Area Quinebaug X 1 1 1 1 1 East Brimfield Reservoir 3 41014 Streeter Point Rec. Area Quinebaug X 1 1 1 1 1 East Lake Waushacum 1 81153 Sterling Nashua X 1 -- 1 1 -- Fearing Pond 1 95054 Myles Standish S.F. South Shore Coastal X 1 -- -- -- 1 Flax Pond 1 96091 Nickerson S.P. Cape Cod X 1 -- -- -- 1 Greenwater Pond 1 21044 October Mt. S.F. Housatonic X 1 -- 1 1 1 Hallockville Pond 1 33009 Mohawk Trail S.F. Deerfield X 1 -- 1 1 1 Hallockville Pond 2 33009 Mohawk Trail S.F. Deerfield X 1 -- 1 1 -- Hopkinton Reservoir 1 82061 Hopkinton S.P. Sudbury (Concord) X 1 -- 1 1 1 Jamaica Pond 1 72052 Boston Charles X 1 -- 1 Laurel Lake 1 35035 Erving S.F. Millers X X 1 2 1 1 1 Little Cliff Pond 1 96170 Nickerson S.P. Cape Cod X 1 -- 2 2 1 Long Pond (Rutland) 1 36082 Rutland S.P. Chicopee X 1 2 1 1 1 Long Pond 1 62108 Freetown/Lakeville Taunton X 1 1 1 -- 1 Long Pond 2 62108 Freetown/Lakeville Taunton X 1 1 1 -- 1 Long Pond 3 62108 Freetown/Lakeville Taunton X 1 1 1 -- 1 Long Pond 4 62108 Freetown/Lakeville Taunton X 1 1 1 -- 1 Long Pond 5 62108 Freetown/Lakeville Taunton X 1 1 1 -- 1 Long Pond Deep hole 62108 Freetown/Lakeville Taunton X -- -- -- 1 1 Lower Naukeag Lake 1 35041 Ashburnham Millers X X 1 1 1 1 1 Mausert's Pond 1 11009 Clarksburg S.P. Hoosic X 1 -- 1 1 1 Mcleod Pond Outlet 33012 Catamount S.F. Deerfield X 1 -- -- -- 1 Table 6. Massachusetts lakes sampled in 1996, 1997, and 1998, and numbers of measurements of water-quality characteristics made for calibration of Landsat-5 Thematic Mapper imagery

—Continued

Lake name Sampling station PALIS code Town/city Drainage basin

Sampled in: Total number of measurements

1996 1997 1998 Chloro- phyll DOC Color Secchi Temper- ature
Table 6 35

Lakes Sampled by USGS and MADEM Staff—Continued

North Pond 1 33014 Savoy Mountain S.F. Deerfield X 1 -- -- -- --

October Mountain Reservoir Deep hole -- October Mountian S.F. Housatonic X 1 -- 1 1 1Onota Lake 1 21078 Pittsfield Housatonic X X X 1 1 1 1 1

Onota Lake 3 21078 Pittsfield Housatonic X 1 1 1 1 1

Otis Reservoir 1 31027 Otis S.F. Farmington X -- -- 1 1 1Otis Reservoir 2 31027 Otis S.F. Farmington X -- -- 1 1 1Otis Reservoir 3 31027 Otis S.F. Farmington X -- -- 1 1 1Otis Reservoir 4 (outlet) 31027 Otis S.F. Farmington X -- -- 1 1 1Otis Reservoir 5 (north 

inlet)

31027 Otis S.F. Farmington X -- -- -- -- 1

Otis Reservoir 6 (south 

inlet)

31027 Otis S.F. Farmington X -- -- -- -- 1

Pentucket Pond Deep hole 91010 Georgetown Parker X 1 -- 1 1 --Pentucket Pond Inlet 91010 Georgetown Parker X 1 -- 1 1 --Pequot Pond 1 32055 Hampton Ponds S.P. Westfield X 1 -- 1 1 1

Pequot Pond 2 32055 Hampton Ponds S.P. Westfield X 1 -- 1 1 1

Plainfield Pond 1 33017 Plainfield Deerfield X 1 -- 1 1 1

Pontoosuc Lake 1 21083 Pittsfield/Lanesboro Housatonic X X X 1 -- 1 1 1

Rico Lake 1 -- Massasoit S.P. Taunton X 1 -- -- -- 1Rico Lake 2 -- Massasoit S.P. Taunton X 1 -- -- -- 1Rocky Pond 1 95119 Myles Standish S.F. South Shore Coastal X 1 -- 1 1 1Sheomet Lake 1 35074 Warwick S.F. Millers X X 2 -- 2 2 2South Pond 1 33019 Savoy Mountain S.F. Deerfield X 1 -- -- -- --

Table 6. 

Stearns Mill Pond 1 82104 Sudbury Sudbury (Concord) X X X 1 1 1 1 1Thompson Pond 1 36155 Rutland S.P. Chicopee X 1 -- 1 1 1Thompson Pond 2 36155 Rutland S.P. Chicopee X 1 -- 1 1 1Turner's Pond 1 95151 Acushnet Cedar Swamp S.R. South Shore Coastal X 1 1 1 1 1

Massachusetts lakes sampled in 1996, 1997, and 1998, and numbers of measurements of water-quality characteristics made for calibration of Landsat-5 

Thematic Mapper imagery—Continued

Lake name Sampling station PALIS code Town/city Drainage basin

Sampled in: Total number of measurements

1996 1997 1998 Chloro- phyll DOC Color Secchi Temper- ature
36 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes Lakes Sampled by USGS and MADEM Staff—Continued Turner's Pond 2 95151 Acushnet Cedar Swamp S.R. South Shore Coastal X 1 -- 1 1 1 Turner's Pond 3 95151 Acushnet Cedar Swamp S.R. South Shore Coastal X 1 2 1 1 1 Upper Naukeag Lake 1 35090 Ashburnham Millers X X 1 1 1 1 1 Upper Spectacle Pond 1 31044 Otis S.F. Farmington X 1 -- 1 1 1 Walden Pond Deep hole 82109 Walden Pond S.R. Concord X 1 -- -- -- 1 Walker Pond 1 41052 Wells S.P. Quinebaug X 1 -- 1 1 1 Walker Pond 3 41052 Sturbridge Quinebaug X 1 -- 1 1 1 Wallum Lake 1 51172 Douglas S.F. Blackstone X 1 -- 1 1 1 Watatic Lake 1 35095 Ashburnham/Ashby Millers X X 1 -- 1 1 1 Watson Pond 6 62205 Taunton Taunton X 1 -- 1 1 1 Webster Lake 1 42064 Webster French X X X 1 1 1 1 1 Webster Lake 2 42064 Webster French X X X 1 1 1 1 1 White Pond (Concord) 1 82118 Concord Sudbury (Concord) X X X 1 1 1 1 1 White Pond (Hudson/Stow) 1 82119 Hudson/Stow Assabet (Concord) X X X 1 1 1 1 1 Whitins Reservoir 1 51179 Douglas Blackstone X X X 1 1 1 1 1 Whitins Reservoir 2 51179 Douglas Blackstone X X 1 1 1 1 1 Whalom Pond 1 81154 Lunenburg/Leominster Nashua X 1 -- 1 1 1 Whitehall Pond 1 36173 Rutland S.P. Chicopee X 1 1 1 1 1 Whitehall Reservoir 1 82120 Hopkinton S.P. Sudbury (Concord) X 1 -- 1 1 1 Whitehall Reservoir 2 82120 Hopkinton S.P. Sudbury (Concord) X 1 -- 1 1 1 Whitehall Reservoir 3 82120 Hopkinton S.P. Sudbury (Concord) X 1 -- 1 1 1 Willet Pond 1 73062 Walpole/Norwood/Westwood Neponset X X 1 1 1 1 1 Winnekeag lake 1 81157 Ashburnham Nashua X X 1 -- 1 1 1 York Lake 1 31052 Stansfield S.F. Farmington X 1 -- 1 1 1 Table 6. Massachusetts lakes sampled in 1996, 1997, and 1998, and numbers of measurements of water-quality characteristics made for calibration of Landsat-5 Thematic Mapper imagery

—Continued

Lake name Sampling station PALIS code Town/city Drainage basin

Sampled in: Total number of measurements

1996 1997 1998 Chloro- phyll DOC Color Secchi Temper- ature
Table 7 37

Table 7. Lake-water-quality data collected within 24 hours of Landsat-5 Thematic Mapper imaging of the lakes, and haze-corrected digital numbers corresponding 

to the station locations in the images—Continued

Station name PALIS code Station identifier Latitude ° ′ ′′ Longitude ° ′ ′′

Chlorophyll

concentration

Secchi 

disk transparency Lake color

Haze-corrected TM digital numbers

TM Band 1 TM Band 2 TM Band 3 TM Band 4

July 22, 1996

Ashland Reservoir 82003 1 42 14 42 71 27 41 4.9 2.2 85 5.1 3.6 5.2 9College Pond 95030 1 41 52 03 70 39 46 3.4 3.2 24 7.1 6.6 5.2 10Dudley Pond 82029 1 42 19 44 71 22 23 -- 1.5 135 18.1 13.6 14.2 22George Lake (Wales Pond) 41016 1 42 03 31 72 13 22 -- 3.0 -- 7.1 5.6 6.2 9Heard Pond 82058 1 42 21 13 71 23 01 -- .9 176 11.1 8.6 11.2 18Hopkinton Reservoir 82061 1 42 15 20 71 30 50 1.8 3.0 68 5.1 5.6 4.2 8Horn Pond 71019 1 42 28 13 71 09 30 5.6 2.2 -- 11.1 10.6 11.2 11Jamaica Pond 72052 1 42 19 04 71 07 12 1.3 5.6 9 10.1 7.6 7.2 11Singletary Lake 51152 1 42 09 40 71 46 50 -- 3.9 -- 8.1 5.6 5.2 9Thompson Pond 36155 2 42 18 30 71 58 10 7.4 1.3 234 14.1 6.6 8.2 13Turner's Pond 95151 1 41 40 46 70 58 40 4.6 .4 445 8.1 5.6 5.2 12Turner's Pond 95151 2 41 40 53 70 58 32 5.7 .5 383 12.1 10.6 10.2 20Turner's Pond 95151 3 41 41 05 70 58 26 7.6 .4 547 7.1 5.6 5.2 12Walden Pond 82109 1 42 26 20 71 20 31 1.3 6.2 62 22.1 13.6 13.2 22Wallum Lake 51172 1A 42 00 57 71 46 12 2.4 4.2 7 10.1 6.6 6.2 9Wallum Lake 51172 1B 42 00 57 71 46 12 2.2 4.9 15 10.1 6.6 6.2 9Whitehall Reservoir 82120 1 42 12 60 71 34 46 4.5 2.9 74 4.1 2.6 4.2 8Whitehall Reservoir 82120 2 42 13 53 71 34 06 3.1 2.1 103 6.1 3.6 4.2 8Whitehall Reservoir 82120 3 42 14 03 71 34 44 4.4 2.4 121 9.1 4.6 4.2 8Winthrop Lake 72140 1 42 11 23 71 25 26 -- 2.7 -- 4.1 3.6 5.2 9

June 23, 1997

Horn Pond 71019 1 42 28 13 71 09 30 5.4 1.9 34 28.2 18.0 24.1 16Lower Naukeag Lake 35041 1 42 39 52 71 57 38 2.9 1.9 30 23.2 11.0 17.1 12Maspenock Lake 51112 Deep end 42 12 10 71 33 29 1.9 -- 25 17.2 10.0 13.1 11Maspenock Lake 51112 Basin 42 11 29 71 33 20 2.9 -- 33 19.2 10.0 15.1 11Merino Lake 42036 1A 42 03 01 71 54 02 7.9 2.8 185 17.2 11.0 14.1 11

Table 7. Lake-water-quality data collected within 24 hours of Landsat-5 Thematic Mapper imaging of the lakes, and haze-corrected digital numbers corresponding 

to the station locations in the images

[PALIS code: PALIS; Pond and Lake Identification System. Latitude and longitude: In degrees, minutes, and seconds. PCU, platinum-cobalt units; TM, Thematic Mapper; m, meters; mg/L, micrograms 

per liter]
38 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes June 23, 1997—Continued Merino Lake 42036 1B 42 03 01 71 54 02 5.6 2.8 29 17.2 11.0 14.1 11 Middle Pond 96198 1 41 40 18 70 24 59 .5 5.7 -- 35.2 20.0 27.1 20 Pentucket Pond 91010 Deep hole 42 43 54 70 59 36 7.9 1.6 72 25.2 14.0 20.1 17 Spy Pond 71040 1A 42 24 32 71 09 09 14.2 1.7 216 24.2 16.0 20.1 13 Spy Pond 71040 1B 42 24 32 71 09 09 5.1 1.7 216 24.2 16.0 20.1 13 Thompson Pond 36155 1 42 17 47 71 58 38 3.0 2.1 279 15.2 10.0 14.1 13 Waban Lake 72125 2 42 17 14 71 18 35 2.2 3.8 137 18.2 11.0 14.1 11 Walden Pond 82109 Deep hole 42 26 20 71 20 31 1.2 -- -- 18.2 11.0 12.1 10 Wallum Lake 51172 1 42 00 57 71 46 12 1.2 5.2 22 18.2 11.0 13.1 10 Warners Pond 82110 1A 42 47 52 71 24 08 10.5 1.7 308 22.2 11.0 18.1 14 Warners Pond 82110 1B 42 47 52 71 24 08 7.1 1.7 80 22.2 11.0 18.1 14 Webster Lake 42064 1A 42 03 14 71 50 56 2.4 4.0 10 20.2 12.0 16.1 11 Webster Lake 42064 1B 42 03 14 71 50 56 1.6 4.0 15 20.2 12.0 16.1 11 Webster Lake 42064 2 42 02 15 71 50 50 1.9 3.4 6 20.2 12.0 17.1 11 White Pond (Concord) 82118 1 42 25 40 71 23 28 3.0 4.2 10 16.2 9.0 13.1 10 Whitins Reservoir 51179 1 42 04 20 71 46 42 .9 4.4 21 20.2 11.0 15.1 12 Winnekeag Lake 81157 1 42 39 48 71 53 55 2.8 2.3 45 15.2 10.0 13.1 10 Winter Pond 71047 1 42 27 22 71 09 15 4.0 2.2 54 16.2 9.0 11.1 8 August 26, 1997 Table 7. Bearse Pond 96012 16 41 40 35 70 20 00 6.4 3.1 -- 8.3 9.2 10.0 9 Boon Lake 82011 LBA1 42 24 13 71 30 08 5.1 4.5 -- 14.3 10.2 10.0 11 Boon Lake 82011 LBA2 42 23 47 71 29 39 10.6 2.1 -- 12.3 10.2 10.0 10 Buffumville Reservoir 42005 1 42 56 47 71 18 17 3.3 3.3 51 16.3 10.2 11.0 12 Chandler Pond 72017 1 42 20 41 71 09 58 -- .6 38 17.3 13.2 17.0 12 Heard Pond 82058 1 42 21 13 71 23 01 71.1 .4 40 17.3 18.2 20.0 17 Long Pond 62108 1A 41 48 43 70 56 39 3.1 -- 51 7.3 7.2 8.0 9 Long Pond 62108 2A 41 48 06 70 56 29 2.6 -- 52 7.3 7.2 9.0 8 Long Pond 62108 3A 41 46 43 70 56 56 5.8 -- 71 7.3 8.2 9.0 8 Long Pond 62108 5A 41 48 47 70 57 09 1.9 -- 53 9.5 7.3 9.8 8 Lake-water-quality data collected within 24 hours of Landsat-5 Thematic Mapper imaging of the lakes, and haze-corrected digital numbers corresponding to the station locations in the images

—Continued

Station name PALIS code Station identifier Latitude

° ′ ′′

Longitude

° ′ ′′

Chlorophyll

concentration

Secchi 

disk transparency Lake color

Haze-corrected TM digital numbers

TM Band 1 TM Band 2 TM Band 3 TM Band 4
Table 7 39

August 26, 1997—Continued

Long Pond 62108 1B 41 48 43 70 56 39 2.4 -- 48 7.3 7.2 8.0 9Long Pond 62108 1C 41 48 43 70 56 39 -- -- 46 7.3 7.2 8.0 9Long Pond 62108 2B 41 48 06 70 56 29 1.5 -- 50 7.3 7.2 9.0 8Long Pond 62108 3B 41 46 43 70 56 56 3.7 -- -- 7.3 8.2 9.0 8Long Pond 62108 5B 41 48 47 70 57 09 2.1 -- -- 8.3 6.2 9.0 8Long Pond 62108 Deep hole 41 48 42 70 56 41 -- 2.1 -- 6.3 6.2 10.0 8Lower Naukeag Lake 35041 1 42 39 52 71 57 38 6.0 1.8 159 8.3 9.2 10.0 11Maspenock Lake 51112 Deep end 42 12 10 71 33 29 2.1 3.4 33 14.3 10.2 13.0 14Maspenock Lake 51112 Basin 42 11 29 71 33 20 2.0 2.1 26 13.3 11.2 13.0 11Merino Lake 42036 1 42 03 01 71 54 02 -- 2.1 -- 10.3 9.2 9.0 11Middle Pond 96198 1 41 40 18 70 24 59 1.9 4.4 -- 6.3 7.2 8.0 9Puffer Pond 82092 1 42 24 20 71 27 36 84.5 .4 132 16.3 18.2 21.0 15Thompson Pond 36155 1 42 17 48 71 58 38 1.7 3.2 78 12.3 8.2 11.0 13Upper Naukeag Lake 35090 1 42 39 39 71 55 50 -- 5.3 -- 12.3 10.2 8.0 10Waban Lake 72125 2 42 17 14 71 18 35 -- 2.7 -- 14.3 11.2 12.0 9Walden Pond 82109 Deep hole A 42 26 20 71 20 31 .9 3.5 -- 15.3 11.2 10.0 12Walden Pond 82109 Deep hole B 42 26 20 71 20 31 1.6 3.5 -- 15.3 11.2 10.0 12Watatic Lake 35095 1 42 40 49 71 56 22 -- 1.1 -- 10.3 9.2 10.0 12Wequaquet Lake 96333 15 41 40 08 70 20 28 6.1 2.6 -- 8.3 10.2 10.0 8White Pond (Concord) 82118 1 42 25 40 71 23 28 -- 8.8 -- 13.3 10.2 10.0 13Winnekeag Lake 81157 1 42 39 48 71 53 55 -- 3.1 -- 9.3 9.2 10.0 11

June 10, 1998

Table 7.

Maspenock Lake 51112 Deep end 42 12 10 71 33 29 4.5 3.0 42 8.5 5.5 8.7 11Maspenock Lake 51112 Basin 42 11 29 71 33 20 4.1 2.0 33 8.5 6.5 10.7 12Middle Pond 96198 1 41 40 18 70 24 59 1.8 5.6 3 15.5 10.5 16.7 16Mystic Lake 96218 1 41 40 32 70 25 02 5.4 4.3 1 13.5 10.5 14.7 16Puffer Pond 82092 1 42 24 20 71 27 36 16.1 .8 300 8.5 5.5 12.7 14

 Lake-water-quality data collected within 24 hours of Landsat-5 Thematic Mapper imaging of the lakes, and haze-corrected digital numbers corresponding 

to the station locations in the images—Continued

Station name PALIS code Station identifier Latitude ° ′ ′′ Longitude ° ′ ′′

Chlorophyll

concentration

Secchi 

disk transparency Lake color

Haze-corrected TM digital numbers

TM Band 1 TM Band 2 TM Band 3 TM Band 4
40 Use of Thematic Mapper Imagery to Assess Water Quality, Trophic State, and Macrophyte Distributions in Massachusetts Lakes June 10, 1998—Continued Table 7. Spy Pond 71040 South 42 24 22 71 09 30 6.4 3.0 30 12.5 10.5 12.7 12 Spy Pond 71040 North 42 24 32 71 09 09 9.1 2.2 49 14.5 10.5 14.7 11 Stearns Mill Pond 82104 1 42 32 10 71 27 01 11.6 -- 98 10.5 7.5 12.7 9 Waban Lake 72125 2 42 17 14 71 18 35 5.7 2.3 291 8.5 6.5 12.7 11 Webster Lake 42064 1A 42 03 14 71 50 56 2.2 5.2 0 19.5 10.5 15.7 19 Webster Lake 42064 1B 42 03 14 71 50 56 1.9 4.3 6 19.5 10.5 15.7 19 White Pond (Concord) 82118 1 42 25 40 71 23 28 3.5 3.3 7 13.5 7.5 10.7 11 White Pond (Hudson/Stow) 82119 1 42 23 30 71 28 49 1.4 6.2 12 9.5 6.5 9.7 12 Whitins Reservoir 51179 1A 42 04 15 71 45 42 1.5 4.4 57 12.5 8.5 12.7 14 Whitins Reservoir 51179 2A 42 04 21 71 46 43 1.1 4.0 27 12.5 8.5 13.7 16 Whitins Reservoir 51179 1B 42 04 15 71 45 42 1.4 4.6 21 12.5 8.5 12.7 14 Whitins Reservoir 51179 2B 42 04 21 71 46 43 1.3 3.7 27 12.5 8.5 13.7 16 Winthrop Lake 72140 Deep hole 42 11 23 71 25 26 6.6 2.6 98 9.5 6.5 9.7 13 Lake-water-quality data collected within 24 hours of Landsat-5 Thematic Mapper imaging of the lakes, and haze-corrected digital numbers corresponding to the station locations in the images

—Continued

Station name PALIS code Station identifier Latitude

° ′ ′′

Longitude

° ′ ′′

Chlorophyll

concentration

Secchi 

disk transparency Lake color

Haze-corrected TM digital numbers

TM Band 1 TM Band 2 TM Band 3 TM Band 4