U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2009–5216

Prepared in cooperation with the Michigan Department of Environmental Quality

Analysis of Water-Quality Trends for Selected Streams 

in the Water Chemistry Monitoring Program, 

Michigan, 1998–2005

Analysis of Water-Quality Trends for 

Selected Streams in the Water Chemistry 

Monitoring Program, Michigan, 1998–2005

By C.J. Hoard, Lori M. Fuller, and Lisa R. Fogarty

Prepared in cooperation with the Michigan Department of Environmental Quality

Scientific Investigations Report 2009–5216

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2009

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reproduce any copyrighted materials contained within this report.

Suggested citation:

Hoard, C.J., Fuller, L.M., and Fogarty, L.R., 2009, Analysis of water-quality trends for selected streams in the 

Water Chemistry Monitoring Program, Michigan, 1998–2005: U.S. Geological Survey Scientific Investigations 

Report 2009–5216, 48 p.
iii

Acknowledgments 

The authors appreciate the helpful reviews from and discussions with Christine Aiello, 

Dawn Roush, and Gary Kohlhepp from the Michigan Department of Environmental Quality.

The authors also wish to thank 

• Tim Willoughby, and Tammy Zimmerman of the USGS who provided technical reviews 

of this report

• the many USGS hydrologic technicians who collected the data for this project, and 

• Stephanie Beeler of the USGS, who assisted with use of the National Water Information 

System (NWIS) database.

v

Contents

Acknowledgments .......................................................................................................................................iii

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

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

Previous Studies ...................................................................................................................................2

Water-Chemistry Monitoring Program..............................................................................................2

Land Use.................................................................................................................................................2

Climate....................................................................................................................................................6

Purpose and Scope ..............................................................................................................................7

Approach.........................................................................................................................................................7

Sampling Design ...................................................................................................................................7

Field Measurements....................................................................................................................8

Sample Collection........................................................................................................................8

Quality-Assurance Samples ......................................................................................................8

Estimating Trends in Water-Quality Data........................................................................................10

Data Requirements....................................................................................................................10

Seasonal Variability...................................................................................................................10

Flow Variability ...........................................................................................................................11

Trend Testing ..............................................................................................................................12

Limitations...................................................................................................................................13

ESTREND Seasonal Kendall Test Results ................................................................................................14

Trends for Physical Water Properties .............................................................................................14

Trends in Chloride Concentrations...................................................................................................16

Trends in Nutrient Concentrations...................................................................................................19

Nitrogen.......................................................................................................................................19

Phosphorus.................................................................................................................................24

Trends in Trace Metals Concentrations..........................................................................................24

Spatial Distribution of Trends............................................................................................................24

Summary and Conclusions.........................................................................................................................30

References Cited..........................................................................................................................................30

Appendix........................................................................................................................................................33

Figures

1–3. Maps showing:

1. Michigan watersheds studied as part of the Michigan Water-Chemistry 

Monitoring Program............................................................................................................3

2. Distribution of land cover by major land-use category in Michigan ..........................5

3. Climate regions and spatial distribution of 30-year average annual 

precipitation in Michigan ...................................................................................................6
vi

4–8. Graphs showing:

4. Distribution of precipitation by year and region in Michigan, 1998–2005 .................7

5. Seasonal variability in nitrate concentration at the Grand River near 

Eastmanville, Michigan.....................................................................................................11

6. Normal and flow-adjusted concentrations for chloride from 

2001 through 2005, Kalamazoo River at New Richmond, Michigan ..........................13

7. Chloride concentrations over time for selected intensively monitored 

stream sites in Michigan, 1999 through 2005 ................................................................17

8. The relation between chloride concentration and streamflow at 

selected stream sites in Michigan, 1999 through 2005................................................18

9. Schematic representation of the nitrogen cycle ..................................................................19

10–14. Graphs showing:

10. Concentration of Total Kjeldahl nitrogen and streamflow, 2000 through 

2005, Clinton River, Michigan...........................................................................................21

12. The relations between concentrations of total Kjeldahl nitrogen and nitrate 

and total suspended solids for the Clinton River, Michigan .......................................22

11. Concentration of nitrate and streamflow, 2000 through 2005, 

Clinton River, Michigan.....................................................................................................22

13. The relation between total suspended solids and streamflow for 

the Clinton River, Michigan ..............................................................................................23

14. Relation between concentration of phosphorus and total suspended solids 

in selected Michigan streams .........................................................................................23

15–18. Maps showing:

15. Trend results for dissolved oxygen, pH, water temperature, and 

specific conductance by Michigan watershed............................................................26

16. Trend results for turbidity, total suspended solids, chloride, and 

phosphorus by Michigan watershed..............................................................................27

17. Trend results for ammonia, nitrate, total Kjeldahl nitrogen, and nitrite 

by Michigan watershed....................................................................................................28

18. Trend results for chromium, copper, lead, and mercury by 

Michigan watershed .........................................................................................................29

Tables

1. Sites sampled as part of the Michigan Water Chemistry Monitoring Program.................4

2. Temporal sampling distribution for each site, 1998–2005, Michigan ...................................9

3. Summary of environmental and replicate sample results...................................................10

4. Definition of seasons used for uncensored Seasonal Kendall test ...................................12

5. Summary of trend-analysis results for Michigan study sites, 1999–2005 .........................14

6. Trends for various physical properties analyzed at Michigan stream sites, 

1999–2005 .....................................................................................................................................15

7. Trend results for chloride at Michigan stream sites, 1999–2005 ........................................17

8. Water-quality criteria for total phosphorus and total nitrogen for 

U.S. Environmental Protection Agency ecoregions in Michigan .......................................19

9. Trend results for nutrients at Michigan stream sites, 1999–2005 .......................................20

10. Trend results for trace metals at selected Michigan stream sites, 1999–2005 ................25
vii

Conversion Factors 

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L), 

micrograms per liter (μg/L), or nanograms per liter (ng/L). The unit milliliter (mL) is defined as 

1/1000 of a liter.

Analysis of Water-Quality Trends for Selected Streams 

in the Water-Chemistry Monitoring Program, 

Michigan, 1998–2005

By C. J. Hoard, Lori M. Fuller, and Lisa R. Fogarty

Abstract

In 1998, the Michigan Department of Environmental 

Quality and the U.S. Geological Survey began a long-term 

monitoring program to evaluate the water quality of most 

watersheds in Michigan. Major goals of this Water-Chemistry 

Monitoring Program were to identify streams exceeding or 

not meeting State or Federal water-quality standards and to 

assess if constituent concentrations reflecting water quality in these streams were increasing or decreasing over time. 

As part of this program, water-quality data collected from 

1998 to 2005 were analyzed to identify potential trends. 

Sixteen water-quality constituents were analyzed at 31 sites 

across Michigan, 28 of which had sufficient data to analyze 

for trends. Trend analysis on the various water-quality data 

was done using the uncensored Seasonal Kendall test within 

the computer program ESTREND. The most prevalent trend 

detected throughout the state was for chloride. Chloride 

trends were detected at 8 of the 28 sites; trends at 7 sites were 

increasing and the trend at 1 site was decreasing. Although no 

trends were detected for various nitrogen species or phosphorus, these constituents were detected at levels greater than the 

U.S. Environmental Protection Agency recommendations for 

nutrients in water. The results of the trend analysis will help to 

establish a baseline to evaluate future changes in water quality 

in Michigan streams.

Introduction

With waters draining to four of the five Great Lakes, 

Michigan serves as a major source of water to the Great Lakes 

Basin. Michigan has 36,350 mi of rivers and streams that drain 

62 major watersheds. Michigan relies on the surface water of 

the state for drinking, recreation, and supporting wildlife. The 

quality of these waters is essential for the health and economy 

of Michigan. 

In 1998, citizens of Michigan passed the Clean 

Michigan Initiative (CMI) to clean up, protect, and enhance 

the environmental infrastructure of Michigan. In 1998, 

because of expanding water-quality data needs, resulting in 

part from the new CMI program, the MDEQ and USGS jointly 

designed and implemented the Water-Chemistry Monitoring 

Program (WCMP) for long-term monitoring of streams in 

Michigan (Michigan Department of Environmental Quality, 

2001). Major goals of the WCMP were to identify streams that 

do not meet water-quality standards and to assess if constituents reflecting water quality in these streams were increasing 

or decreasing in concentration over time.

Long-term water-quality monitoring is necessary to 

detect changes or trends in rivers and streams in Michigan. 

Changes in land management, water-treatment practices, and 

land use commonly lead to changes in chemical inputs to 

nearby surface waters. The WCMP long-term water-quality 

monitoring used a two-phased approach. Initially, the WCMP 

helped to establish baseline water quality for rivers and 

streams. Once the baseline water quality was established, 

continued monitoring allowed assessment of water-quality 

trends. This type of monitoring program can help identify 

the need for remediation or changes in current management 

practices and also verify that changes to prior water or landmanagement practices have had an effect on water quality. 

Changes in water quality of a river or stream can be the 

result of several factors. For example, shifting from agricultural to residential land use could result in changes in water 

quality. As the population grows, so does the number and size 

of urban centers. In several areas of Michigan, agricultural 

lands are being converted to residential or commercial land 

use to meet the needs of the growing population. As the 

population continues to grow, water-management practices 

need to be adjusted to handle the increased demand on water 

resources as well as to treat the increased amount of wastewater generated. Through an understanding of the hydrologic 

processes governing our environment, there is recognition that 

land-management practices can be improved in an effort to 

control the amount and type of chemical inputs into our surface waters. For example, the growing demand for alternative 

fuels may lead to increased crop production and the increased 

use of associated agricultural chemicals. Land-management 

practices, such as agricultural best-management practices 

(BMPs), can be instituted and improved to control the amount 
2 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

of and types of chemicals entering the environment from 

increased crop production. Alternatively, changes in land use 

with no adaptation of water or land-management practices 

may lead to degradation of water quality in surface water.

For most streams currently sampled as part of the WCMP 

program, at least 5 years of water-quality data were available. 

Statistical techniques used to estimate trends have a minimum 

period of record necessary for analysis. The technique used in 

this study required a minimum of 5 years of continuous data. 

Previous Studies

Blumer (1993) published results for stream water-quality 

analyses for 10 monitoring stations throughout Michigan from 

1987 to 1989 and trend analyses for 16 monitoring stations 

from 1975 to 1989. Syed and Fogarty (2005) published results 

of water-quality trend analyses for nine streams in Michigan 

sampled from 1978 to 1995 as part of the USGS National 

Stream Quality Accounting Network (NASQAN). Results 

from these studies showed both upward and downward trends 

in concentrations of several water-quality constituents during 

the study periods. From 1978 to 1995, several changes, which 

were brought about by the passage of the Clean Water Act 

of 1972, helped protect water quality. Because of changes 

in policy, land use, and climate over time, changes in waterquality trends for various constituents were expected (Syed 

and Fogarty, 2005).

In 1998, the MDEQ, in cooperation with the USGS 

Michigan Water Science Center, began monitoring 31 stream 

sites in Michigan as part of a long-term monitoring program. 

This program included monitoring the water chemistry of 

27 watersheds draining to the Great Lakes, some of which 

were also part of the historical NASQAN program (Michigan 

Department of Environmental Quality, 2008b). 

Water-Chemistry Monitoring Program

In 1998, the MDEQ began monitoring 27 different watersheds in Michigan as part of the WCMP (fig. 1). The WCMP 

incorporated the watershed-management units and 5-year rotational cycle used by the MDEQ Ambient Surface Water Chemistry Monitoring Program (Michigan Department of Environmental Quality, 2001) to assess Michigan streams, Great Lakes 

connecting channels, and bays. This was done to ensure that 

specific watersheds were monitored in a 5-year cycle to assist 

in (1) statewide water-quality assessments, (2) the National 

Pollutant Discharge Elimination System (NPDES) permitting 

process, and (3) resource-management decisions. 

The areas selected for monitoring coincide with USGS 

eight-digit hydrologic units throughout the state. Sampling 

locations in these hydrologic units were selected near the 

mouth of major streams draining to the Great Lakes. This 

was done to provide a sample that best represents the average 

water quality of the hydrologic unit. Land use varied from 

undeveloped forest in the northern parts of the state to highly 

developed urban centers in the southern part of the state 

(fig. 2). Six hydrologic units representing the varying conditions from urban to undeveloped were monitored intensively 

every year. Twenty-one other hydrologic units were monitored 

through 25 additional sampling sites, also representing a broad 

range of land-use conditions (table 1). 

Land Use

Land use is a major factor affecting streamflow and the 

types of constituents that may run off to streams. For instance, 

in a watershed with a large amount of agricultural land use, 

there is a potential for increased input of nutrients to the 

stream as a result of fertilizer usage. Other land-use categories 

may have unique effects on water quality based on the possible types of chemicals available to run off into the streams.

Four major categories were used in this study to classify 

the land use throughout the State of Michigan. The major categories used were agricultural, urban, undeveloped, and water. 

Agricultural land use includes land used for the production of 

cultivated crops, livestock, and orchards. The urban land-use 

category includes commercial, industrial, and residential areas. 

The undeveloped land-use category is used to classify many 

categories but primarily forests, shrublands, and wetlands. 

The water land-use category is area covered by large bodies of 

water like lakes or large rivers. Much of the land use identified 

in watersheds in the Upper Peninsula and northern Lower Peninsula of Michigan is comprised of forest, wetland, and other 

open or undeveloped land coverage. In contrast, the southern 

Lower Peninsula of Michigan is primarily agricultural and 

urban (fig. 2). 
Introduction 3

0 50 100 KILOMETERS

0 50 100 MILES

n

n

n

n

n

n

n

n

n n n

n

n

n

n

n

n

n

n

n

n

n

n

n

n

n

n

nnn

n

n

n

EXPLANATION

Sampling location

Integrator

Intensive

Watershed number

Streamflow gaging

 station location

85°W

88°W

46°N

43°N

Watershed

16

5

18 19

1

2

4

3

6

30

23

29

14

20

21

26

25

31

8

7

9

10

12

22

28

11

13

27

15

24

17

Basemap: State and County boundaries from the Michigan Geographic Framework, 2003. Watershed boundaries from 1:250,000 

Hydrologic Unit Codes (U.S. Geological Survey, 1994)and split if necessary using upstream 1:24,000 watershed boundaries 

(Michigan Department of Environmental Quality, 1998). 

1

Figure 1. Michigan watersheds studied as part of the Michigan Water-Chemistry Monitoring Program.
Table 1. Sites sampled as part of the Michigan Water Chemistry Monitoring Program.[Bold type indicates intensively sampled site; USGS, U.S. Geological Survey; USEPA, U.S. Environmental Protection Agency] Watershed number Site name USGS station number USEPA STORET number Latitude 

1 Ontonagon River at Ontonagon, Mich. 04040018 660038 46.86744 2 Menominee River at Menominee, Mich. 04067648 550038 45.10637 3 Escanaba River at Wells, Mich. 040590345 210102 45.78111 4 Sturgeon River at County Road 499 at Nahma, Mich. 04057521 210032 45.84081 5 Manistique River Above Manistique, Mich. 04057004 770073 45.97164 6 Tahquamenon River at Emerson, Mich. 04045510 170141 46.55641 7 Pine River near Charles, Mich. 04127925 490006 46.05696 8 Cheboygan River at Cheboygan, Mich. 04132052 160073 45.63390 9 Boardman River near Traverse City, Mich. 04127200 280014 44.67528 

10 Manistee River at Parkdale, Mich. 04126010 510088 44.26417 

11 Pere Marquette River at Scottville, Mich. 04122500 530027 43.94501 

12 (lower) Muskegon River near Bridgeton, Mich. 04122030 610273 43.31807 13 (upper) Muskegon River near Hersey, Mich. 04121621 670008 43.84722 14 (lower) Grand River near Eastmanville, Mich. 04119400 700123 43.02419 15 (upper) Grand River at Ionia, Mich. 04116000 340025 42.97198 16 (lower) Kalamazoo River at New Richmond, Mich. 04108660 030077 42.65169 17 (upper) Kalamazoo River near Augusta, Mich. 04105707 390057 42.32560 18 (lower) St. Joseph River at Napier Ave at St. Joseph, Mich. 04102080 110628 42.08921 19 (upper) St. Joseph River at Mottville, Mich. 04099000 750273 41.80088 20 River Raisin at Monroe, Mich. 04176540 580046 41.91338 21 Huron River at Rockwood, Mich. 04175120 580364 42.06417 22 River Rouge at River Rouge, Mich. 04168550 820070 42.28059 23 Clinton River at Gratiot Avenue at Mt. Clemens, Mich. 04165553 500233 42.58392 24 Black River at Port Huron, Mich. 04160075 740385 42.99440 25 Flint River near Fosters, Mich. 04149000 730285 43.30836 26 Cass River near Bridgeport, Mich. 04152002 730024 43.36503 27 Shiawassee River near Fergus, Mich. 04145000 730023 43.25475 28 Tittabawassee River at Center Road near Saginaw, Mich. 04156510 730025 43.39364 29 Saginaw River at Weadock Road at Essexville, Mich. 04157065 090177 43.62808 30 Au Sable River near Au Sable, Mich. 04137500 350061 44.43640 31 Thunder Bay at Alpena, Mich. 04135020 040123 45.07085 
Introduction 5

Urban

Undeveloped

Agriculture

Water

0 50 100 KILOMETERS

0 50 100 MILES

EXPLANATION

Sampling location

Integrator

Intensive

16

5

18 19

1

2

4

3

6

30

23

29

14

20

21

26

25

31

8

7

9

10

12

22

28

11

13

27

15

24

17

Watershed

Land use

Basemap: State and County boundaries from the Michigan Geographic Framework, 2003.Watershed boundaries from 1:250,000 

Hydrologic Unit Codes (U.S. Geological Survey, 1994) and split if necessary using upstream 1:24,000 watershed boundaries

(Michigan Department of Environmental Quality, 1998). 

1 Watershed number

Figure 2. Distribution of land cover by major land-use category in Michigan.
6 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

Climate

Climate differences can be expected between the different 

regions of the state. In particular, the distribution of precipitation across Michigan is highly variable (fig. 3). Precipitation is 

a major factor affecting streamflow. Precipitation can contribute to streamflow either as direct runoff from the land surface 

to streams or as water that has infiltrated into groundwater and 

is discharged to streams through base flow. In addition, higher 

precipitation may lead to a higher contribution of chemical inputs to streams because runoff from the land surface 

frequently carries constituents applied to or deposited on the 

land surface. 

The National Oceanic and Atmospheric Administration 

(NOAA) defined 10 climate divisions for the State of Michigan. For simplicity, these divisions were grouped into four 

regions: the Upper Peninsula, Northern Lower Peninsula, 

Central Lower Peninsula, and Southern Lower Peninsula 

(fig. 3). Average annual precipitation, by region, from 1998 

to 2005 (National Oceanic and Atmospheric Administration, 

1999–2006), ranged from 27 in. (for the Upper Peninsula 

region in 2000) to 41 in. (for the Southern Lower Peninsula 

region in 2000). The areas of relatively high precipitation were 

near the Great Lakes coastlines, which show the distinct influence of lake-effect precipitation. Average annual precipitation 

for each region for the study period is shown in figure 4.

EXPLANATION

30-year average annual

precipitation (inches)

1971−2001

 39.9

27.0

Upper Peninsula

Northern Lower Peninsula

Central Lower Peninsula

Southern Lower Peninsula

0 50 100

0 50 100

KILOMETERS

MILES

Digital data: PRISM Climate Group, Oregon State University, 

http://www.prismclimate.org, created June 23, 2008

Figure 3. Climate regions and spatial distribution of 30-year average annual precipitation in Michigan.
Approach 7

Purpose and Scope

This report summarizes estimated trends in water-quality 

data collected as part of the MDEQ WCMP program from 

1998 to 2005. The report describes the seasonal trend-analysis 

procedure used to evaluate trends in select water-quality constituents for 31 stream sites across 27 watersheds in Michigan. The data collected and analyzed in this report lay the 

foundation for future analysis of trends as part of the WCMP 

long-term water-quality monitoring effort. As additional data 

are collected, the trend analysis can be updated to reflect the 

most current conditions. Because this report is intended to 

serve as a preliminary analysis of the long-term state monitoring program, long-term predictions of water quality have not 

been included. Potential factors that may have influenced past 

water quality at these sites are mentioned, but the intent of this 

report is not to determine sources of contamination or remedial action strategies. 

Approach

Sampling Design

In cooperation with MDEQ, the USGS collected waterquality samples at 6 intensively monitored sites (Au Sable 

River, Clinton River, Grand River, Kalamazoo River, Muskegon River, and Saginaw River) 12 times a year from 2001 to 

present (2008). Additional samples also were collected from 

1998 to 2000; however, the data collected in that time span 

were not continuous. This report summarizes the trends for 

water-quality data collected from 1998 to 2005. The sampling 

design for the WCMP study was to collect 8 of the 12 samples 

during high-flow conditions. The remaining four samples were 

collected during low-flow conditions. Typically, samples were 

collected March through November, but on a few occasions 

samples were collected in January and February during major 

thaw and runoff events. 

Figure 4. Distribution of precipitation by year and region in Michigan, 1998–2005 (National Oceanic and Atmospheric Administration, 

1999–2006).

Upper Peninsula Northern Lower

 Peninsula

Central Lower

 Peninsula

Southern Lower 

Peninsula

25

30

35

40

ANNUAL PRECIPITATION IN INCHES

1998

1999

2000

2001

2002

2003

2004

2005

STATE DIVISIONS

EXPLANATION
8 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

In addition to the 6 intensively monitored sites sampled 

each year from 2001 to present (2008), 25 integrator sites 

also were sampled 12 times per year, but on a 5-year rotating 

basis. During non-intensive years, these integrator sites were 

sampled quarterly, independent of streamflow conditions. 

For example, the Cass River (table 2) was sampled 12 times 

in 2001 and 4 times per year over the next 4 years. Again, 

samples also were collected during 1998–2000 for the integrator sites, but the water-quality record in that time span was not 

continuous. The number of samples collected each year for the 

WCMP monitoring program is summarized in table 2. 

Field Measurements

Field measurements are the measurements of physical 

and chemical properties of water at a sample site as close as 

possible in time and space to the stream-water-quality sample 

being collected (Wilde and Radtke, 2005). Certain constituents 

like temperature, pH, dissolved oxygen (DO), and specific 

conductance are best measured in the field because of the 

inability to maintain those constituents during the shipping 

and analysis process. To measure these onsite constituents, 

a calibrated multiparameter water-quality instrument was 

used at each sampling location. Where appropriate, three 

measurements were taken: one at a distance of one-quarter of 

the stream width from the right bank, one in the center of the 

channel, and one at a distance of one-quarter of the stream 

width from the left bank. These three measurements were then 

averaged and used to represent the conditions of the stream. 

When three sections were not possible, the measurements 

were taken from the center of the channel at the sampling site. 

All measurements were taken at approximately 2 ft below the 

water surface. 

Mean daily streamflow values for each sample were 

obtained from the streamflow gaging station at the sampling 

site. When a streamflow-gaging station was not located at the 

sampling site, a drainage-area multiplier was determined for 

the area that contributed flow to that sample site. This multiplier was used in conjunction with the flow from a nearby 

streamflow-gaging station, usually located upstream, to 

estimate the mean daily streamflow at the sample location. If 

more than one streamflow-gaging station was near a sampling 

location, a drainage-area multiplier was developed and used in 

conjunction with streamflow values from multiple streamflowgaging stations to estimate the mean daily streamflow for the 

sampling location.

Sample Collection

For streams that could be safely waded, water samples 

for trace metals, total mercury, nutrients, chloride, and total 

suspended solids (TSS) were collected as a single grab sample 

in the center of flow about 2–3 ft below the water surface. For 

streams that could not be waded, water samples for mercury 

and trace metals were collected using a peristaltic pump either 

from a bridge or from a boat with C-Flex® tubing connected 

to 6–15 ft of Teflon® tubing. Teflon tubing was connected to a 

Teflon counter weight and dropped below the surface, approximately 2–3 ft, in the center of the channel. Water samples for 

mercury analysis were collected in 500 mL Teflon bottles, and 

water samples for analysis of trace metals were collected in 

250 mL Teflon bottles. Prior to sample collection, the tubing 

was rinsed with sample water for 5 minutes. Sample bottles 

were sealed in plastic bags and placed on ice in a cooler until 

final processing and transportation. The Teflon and C-Flex® 

tubing were rinsed with 2-percent nitric acid and then rinsed 

in deionized water. The Teflon line was stored until the next 

sampling, whereas the C-Flex® tubing was sent back to the 

Wisconsin State Lab of Hygiene (WSLH). Water samples for 

mercury and trace metals were shipped in a cooler with ice to 

the WSLH, Madison, Wis., within 48 hours of sample collection. 

Water samples for nutrients, chloride, and TSS were 

collected in 500 mL polypropylene bottles using grab, peristaltic pump, sampling can, and (or) Van Dorn samplers, as 

appropriate. Sample bottles were placed on ice in a cooler 

until final processing and transportation. To improve sample 

preservation, the samples that were analyzed for total organic 

carbon, nitrate, nitrite, ammonia, Total Kjeldahl nitrogen 

(TKN), and total phosphorus (TP) were amended with 10 

drops of concentrated sulfuric acid in the field. Samples were 

placed in a cooler with ice and shipped or transported to the 

MDEQ Environmental Laboratory, Lansing, Mich., within 

48 hours of sample collection. Sample analyses and results 

are summarized in MDEQ water-chemistry trend monitoring reports (Michigan Department of Environmental Quality, 2001; Michigan Department of Environmental Quality, 

2002: Michigan Department of Environmental Quality, 2003; 

Michigan Department of Environmental Quality, 2004; Michigan Department of Environmental Quality, 2005; Michigan 

Department of Environmental Quality, 2006a; Michigan 

Department of Environmental Quality, 2008a). 

Quality-Assurance Samples

As part of the WCMP, quality-assurance samples that 

consisted of a series of blank and replicate samples were collected. Blank samples were used to assess whether or not the 

sampling techniques or methods were introducing contamination to the samples collected. Between 6 and 15 blank samples 

were collected and analyzed for all the constituents each year. 

Results from the field blanks and trip blanks were below 

quantification levels for all the constituents reported in the 

study with the exception of specific trace metal samples. For 

the 72 blank samples analyzed for trace metals, concentrations 

of chromium and mercury were greater than their specified 

detection levels 19 and 4 percent of the time, respectively. 

This indicates that during some step in the sample collection/

analysis process, some low-level contamination of the sample 

may have occurred with regard to certain trace metals.
Table 2. Temporal sampling distribution for each site, 1998–2005, Michigan.

Watershed 

number Site name Samples by year 

1998 1999 2000 2001 2002 2003 200

Intensive sites

12 Muskegon River near Bridgeton 0 12 6 12 12 12 12 14 Grand River near Eastmanville 0 13 6 12 12 12 12 16 Kalamazoo River at New Richmond 0 13 6 12 12 12 12 23 Clinton River at Gratiot Avenue at Mt. Clemens 13 0 6 12 12 12 12 29 Saginaw River at Weadock Road at Essexville 8 0 0 12 12 12 12 30 Au Sable River near Au Sable 11 0 6 12 12 12 12 

Integrator sites

1 Ontonagon River at Ontonagon 0 0 3 4 4 4 4 2 Menominee River at Menominee 0 0 3 4 12 4 4 3 Escanaba River at Wells 0 13 6 4 4 4 4 4 Sturgeon River at County Road 499 at Nahma 0 0 3 12 4 4 4 5 Manistique River Above Manistique 0 13 3 4 4 4 12 6 Tahquamenon River at Emerson 0 13 3 4 4 4 12 7 Pine River near Charles 0 0 3 4 4 4 12 8 Cheboygan River at Cheboygan 0 0 6 4 4 4 4 9 Boardman River near Traverse City 0 0 0 4 4 12 4 

10 Manistee River at Parkdale 0 0 3 4 4 4 12 

11 Pere Marquette River at Scottville 0 12 6 4 5 4 4 

13 Muskegon River near Hersey 0 0 3 12 5 4 4 15 Grand River at Ionia 0 0 3 12 4 4 4 17 Kalamazoo River near Augusta 0 0 3 4 4 4 12 18 St. Joseph River at Napier Ave at St. Joseph 0 12 3 12 4 4 4 19 St. Joseph River at Mottville 0 0 6 4 4 4 4 20 River Raisin at Monroe 12 0 3 4 4 12 4 21 Huron River at Rockwood 12 0 3 4 12 4 4 22 River Rouge at River Rouge 13 0 6 4 4 4 4 24 Black River at Port Huron 0 0 3 4 4 4 4 25 Flint River near Fosters 0 0 3 4 4 12 4 26 Cass River near Bridgeport 0 0 3 12 4 4 4 27 Shiawassee River near Fergus 13 0 6 4 4 4 4 28 Tittabawassee River at Center Road near Saginaw 13 0 3 4 12 4 4 31 Thunder Bay at Alpena 11 0 6 4 4 4 4 
10 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

Replicate samples were used to assist in determining the 

variability in constituent concentrations as a result of sample 

collection, processing, and lab analysis. The number of replicate samples collected ranged from 68 to 124. Comparison of 

the environmental samples to the replicate samples collected 

(table 3) reveals that most constituents have a low percent 

relative standard deviation. This indicates there is good 

precision in the collection and analysis of the constituents 

sampled. However, total suspended solids had a higher percent 

relative standard deviation than the other constituents sampled. 

This indicates there is lower precision with the collection and 

analysis of total suspended sediment. 

Estimating Trends in Water-Quality Data

To evaluate potential trends in select water-quality 

constituents, the statistical software package S-Plus was used 

in conjunction with the trend-estimating program ESTREND 

(Schertz and others, 1991). ESTREND allows for the use of 

both parametric as well as nonparametric techniques to test for 

potential trends. The nonparametric approach of the uncensored Seasonal Kendall test was chosen for this study because 

of the characteristics of the water-quality data collected in the 

WCMP program. The water-quality data collected as part of 

this program generally 1) were not normally distributed; 

2) have seasonal variability in concentrations; 3) have variability in concentrations related to streamflow; 4) have some 

outlier concentration values; 5) have some censored concentration values; and 6) have some missing concentration values. 

The uncensored Seasonal Kendall test was able to account for 

these characteristics of the data, whereas standard parametric procedures would have difficulty evaluating this data set 

(Hirsch and others, 1982; Hirsch and others, 1991).

Data Requirements

The uncensored Seasonal Kendall test for trend detection 

has four primary data requirements. The period of record for a 

water-quality site must be at least 5 years (Schertz and others, 

1991). The minimum number of samples that can be tested 

for at a particular sampling site is at least 3 times the number 

of designated annual seasons, or at least a minimum of 10 

samples (Schertz and others, 1991). Additionally, a minimum percentage, in this case 30 percent, of the total possible 

number of seasonal water-quality values in the beginning and 

ending fifths of the record must be present (Schertz and others, 

1991). Finally, no more than 5 percent of the observed values 

can be censored (Schertz and others, 1991). Censored values 

are results for concentrations of constituents that are less than 

the laboratory method reporting level. These values are not 

quantified but are given a value of less than some reporting 

level. Three sites (watershed numbers 9, 29, and 31, fig. 1) 

were not evaluated for trends because the site did not have the 

minimum length of record, had too few observations, or had 

too many censored values. In the case of the Saginaw River 

site (watershed number 29), even though it was intensively 

sampled, the site was not be sampled between November 1998 

and July 2001. This gap in the record was too large for the 

trend-analysis program ESTREND to provide a reliable trend 

estimate. 

Seasonal Variability

Seasonal differences in concentrations of water-quality 

constituents can complicate the detection of trends. The variability in total nitrate concentrations by month for the Grand 

River near Eastmanville, Mich., is shown in figure 5. To detect 

Table 3. Summary of environmental and replicate sample results.

[mg/L, milligrams per liter; μg/L, micrograms per liter; ng/L, nanograms per liter; P, phosphorus; N, Nitrogen]

Constituent

Number of 

replicate 

samples

Mean 

environmental 

sample

concentration

Mean replicate 

sample 

concentration

Mean of the 

environemntal/

replicate pair 

concentration

Mean standard 

deviation

Mean percent 

relative 

standard 

deviation

Ammonia (mg/L as N) 69 0.055 0.054 0.054 0.001 4.9

Chloride (mg/L) 124 42.234 42.056 42.145 0.445 2.8

Chromium (μg/L) 84 0.482 0.488 0.485 0.029 9.1

Copper (μg/L) 97 1.143 1.237 1.190 0.097 5.1

Lead (μg/L) 97 0.455 0.453 0.454 0.014 4.3

Mercury (ng/L) 65 2.816 2.853 2.834 0.281 11.0

Nitrate (mg/L as N) 86 0.982 0.979 0.980 0.035 4.3

Nitrite (mg/L as N) 72 0.017 0.017 0.017 0.00038 3.0

Total Phosphorus (mg/L as P) 74 0.052 0.052 0.052 0.002 5.7

Total Kjehldahl Nitrogen (mg/L as N) 74 0.583 0.594 0.588 0.018 3.4

Total Suspended Solids (mg/L) 98 16.612 16.980 16.796 1.414 17.2
Approach 11

a trend, the effect of seasonal differences on a constituent 

concentration needs to be removed. The ESTREND program 

does this by dividing a year into seasons and only comparing 

sample data collected from similar seasons to estimate a trend 

(Schertz and others, 1991). 

Seasons, for the different sites and constituents analyzed 

for trends, were defined on the basis of the sampling frequency 

at a site and the distribution of concentration data over time. 

The number of seasons per year used in this study was 12, 6, 

4, 3, or 2 (table 4). The ESTREND program has an automated 

procedure for selecting the most appropriate number of seasons to use in the uncensored Seasonal Kendall test (Schertz 

and others, 1991). The program combines the beginning and 

ending fifths of the water-quality data for a constituent and 

compares that to the middle three-fifths of the record. This 

procedure then calculates the total possible number of seasonal comparisons that could be made given a certain period 

of record and compares that to the actual number of seasonal 

comparisons that can be made on the basis of the data available for a certain constituent at a site. The seasonal definition 

that had the largest number of seasons and that had 50 percent 

or more of the total possible seasonal matches was selected. 

Emphasis was placed on the beginning and ending fifths of the 

record, so the seasonal definition procedure weighted those 

portions of the record higher than the middle three-fifths. 

When a season for a particular year had multiple samples, the 

most central value with respect to time that also was paired 

with a flow estimate was selected to represent the season 

(Schertz and others, 1991).

Flow Variability

The concentrations of various water-quality constituents 

commonly are related to streamflow. As a result, the variance 

in a streams flow may be one of the major influences on a 

constituent concentration over time. In many cases, the influence of streamflow may be greater than the influence of other 

anthropogenic factors on constituent concentrations. In this 

case, any trend analysis test used essentially would be examining trends in streamflow as opposed to trends in constituent 

concentrations. To better understand the anthropogenic effect 

on the concentrations of water-quality constituents in streams, 

the effect that variation in streamflow has on constituent concentrations needs to be removed. 

ESTREND provides a utility to remove the variability in 

constituent concentrations as a result of streamflow variability. 

This utility requires a streamflow estimate for each constituent concentration at each site being tested. ESTREND then 

computes a relation between the constituent concentration and 

MONTH

CONCENTRATION OF NITRATE, IN MILLIGRAMS PER LITER AS NITROGEN

x

x

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

30 number of 

 values

EXPLANATION 

x

75th percentile

median

25th percentile

4 6 9 10 6 8 10 6 8 8

0

1

2

3

4

5

6

Data value between 1.5 

and 3 times the

 interquartile range

Data value between 1.5 

times the interquartile 

range and the last quartile

Figure 5. Seasonal variability in nitrate concentration at the Grand River near Eastmanville, Michigan.
12 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

The p-value generated, on the basis of a standard normal 

distribution, is used to measure the probability of a detectable 

trend.

A trend is defined as a change in a single direction 

(upward/downward) in constituent concentrations over time. 

For this study, a trend is considered to be statistically significant if the p-value of the trend test for a constituent is less 

than or equal to 0.10. The p-value is the probability that a 

detected trend resulted from a chance arrangement of the data, 

rather than from an actual change in constituent concentration. 

Therefore, there is a 10-percent chance that a detected trend is 

an artifact of a chance arrangement of data as opposed to an 

actual trend in constituent concentrations. The default p-value 

used for indicating a significant trend in the ESTREND 

program is a more stringent 0.05. This study opted to use a 

larger p-value (0.10) so more potential trends could be identified in this initial phase of the data collection. In addition, 

previous trend research done on Michigan streams used a 

p-value of 0.05 to identify potential trends. For comparison 

purposes, it was important to show trends at both p-values of 

0.10 and 0.05. 

The magnitude of the detected trend is also estimated 

using ESTREND. The magnitude is actually the trend slope or 

the rate at which a concentration is increasing or decreasing 

over time. This slope is the median slope of all pair-wise comparisons of the concentration data. Each pair-wise difference is 

divided by the number of years separating the pair of concentrations (Schertz and others, 1991). When the concentration 

data are log transformed and flow adjusted in the process of 

determining a trend (as in this study), the trend slope is best 

represented as a percent change in concentration. 

Table 4. Definition of seasons used for uncensored Seasonal Kendall test.

Number of 

seasons 

per year

Season number

1 2 3 4 5 6

12 01/01–02/28 03/01–03/24 03/25–04/18 04/19–05/12 05/13–06/06 06/07–06/30

6 01/01–02/28 03/01–04/30 05/01–06/30 07/01–08/30 08/31–10/31 11/01–12/31

4 01/01–03/31 04/01–06/30 07/01–09/30 10/01–12/31

3 01/01–04/30 05/01–08–31 09/01–12/31

2 01/01–06/30 07/01–12/31

the streamflow estimate, effectively creating a flow-adjusted 

concentration (FAC) value (Schertz and others, 1991). For this 

study, a locally weighted scatter plot smoothing (LOWESS) 

technique (Helsel and Hirsch, 2002) was used to develop the 

FAC values. These FAC values were then tested for possible 

trends using the uncensored Seasonal Kendall test. For example, the variability of chloride concentration for 2001 through 

2005 is shown in figure 6 (fig. 1, number 16). Following the 

flow-adjustment routine, the effect of flow on chloride concentration is removed, and deviations from normal concentration 

patterns are more easily observed. 

Trend Testing

The uncensored Seasonal Kendall test is a nonparametric 

test used to detect possible trends in water-quality constituents over time (Schertz and others, 1991). In contrast to using 

parametric methods, the nonparametric Seasonal Kendall test 

does not use the actual concentration for a constituent, but it 

assigns a rank to each concentration. These ranked concentrations are then compared to other ranked concentrations 

from the same season. The test makes all possible pair-wise 

comparisons of the ranked concentrations for the period of 

record of the constituent being tested. For instance, when 

later concentrations (in time) have a higher rank, a positive 

result is recorded; if a later concentration has a lower rank, a 

negative result is recorded. The test statistic is computed as the 

difference between the total number of positive and negative 

results in the record. The cumulative result of the test statistic 

is then compared to zero. If the test statistic is much greater or 

lower than zero, the probability of trend in the data is higher. 

Table 4. Definition of seasons used for uncensored Seasonal Kendall test.—Continued

Number of 

seasons 

per year

Season number

7 8 9 10 11 12

12 07/01–07/25 07/26–08/18 08/19–09/12 09/13–10/06 10/07–10/31 11/01–12/31

6

4

3

2
Approach 13

20

30

40

50

60

CHLORIDE CONCENTRATION, IN MILLIGRAMS PER LITER

FLOW ADJUSTED CHLORIDE CONCENTRATION -0.5

-0.3

-0.1

0.1

0.3

0.5

2001 2002 2003 2004 2005 2006

Figure 6. Normal and flow-adjusted concentrations for chloride from 2001 through 2005, Kalamazoo River at New Richmond, Michigan. 

Limitations

Although the data collected as part of this study meet 

the criteria for using the uncensored Seasonal Kendall test for 

trends, the use of this data set has some limitations associated with it. Ideally, trend analysis should be performed on a 

data set collected at a regularly spaced interval throughout the 

year. Collecting samples on a set schedule avoids introducing 

temporal bias that may obscure potential trend determination 

(Schertz and other, 1991). In addition, studies should avoid 

any planned bias toward any particular level of streamflow 

(Schertz and others, 1991). For this study, during intensive 

sampling periods, sample collection was weighted toward high 

streamflow conditions as opposed to collecting on regularly 

spaced interval. As a result, there is potential for bias to 

affect the determination of trends for this study. During the 

non-intensive phase of sampling for the integrator sites, this 

was not an issue because samples were collected at a regularspaced interval. 

The reason for this distribution of samples in the WCMP 

was that the MDEQ had two major goals for the tributarymonitoring component: 1) to calculate loadings of selected 

chemical indicators from major Michigan rivers into the 

Great Lakes, and 2) to measure spatial and temporal trends 

in contaminant concentrations. The MDEQ recognized that 

accommodating both goals required compromises in study 

design. That is, had the only goal been to calculate loads or 

only to assess trends, the design probably would have been 

different than the one ultimately adopted. Despite the constraints, the current approach was considered sufficient to 

satisfy both goals with the recognition that the design should 

be evaluated after some years of data became available. 

To accomplish the first goal, the peer-reviewed study 

design established for the Lake Michigan Mass Balance 

Project was followed. Specifically, this protocol called for 

flow-stratified sampling in which approximately 75 percent of 

the samples would be collected during high-flow events from 

the target tributaries in selected years. To meet the second 

goal, water samples were collected at four pre-determined 

dates per year, regardless of flow, from each tributary during 

non-loading years (4 out of every 5 years for most rivers). 

This approach was based on separate reviews of fixed-station 

stream/river data from New Jersey and Wisconsin, both of 

which sample quarterly (New Jersey Department of Environmental Protection, 1998; Team for Evaluating the Wisconsin 

Water-Monitoring Network, 1998). In particular, Wisconsin 

concluded that four samples per year were sufficient to detect 

water-quality trends.
14 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

ESTREND Seasonal Kendall Test 

Results

Trend results are reported for 16 constituents sampled at 

28 sites throughout Michigan from 1998 to 2005. Statistically 

significant trends are summarized in table 5 as well as appendix 1. It is important to understand that significant trends may 

be a result of small changes in constituent concentrations over 

time. Detected trends should be assessed in the context of the 

potential effect that a constituent can have on the environment. 

These trends may be a result of processes that are naturally 

occurring, anthropogenic, or a combination of both.

Trends for Physical Water Properties

The major physical properties analyzed for trends were 

dissolved oxygen, pH, specific conductance, water temperature, turbidity, and total suspended solids. Significant trends 

were detected for all of these constituents for at least one site. 

The trends detected for the various physical properties analyzed are listed in table 6. 

DO is a measure of how much oxygen is present in water. 

Aquatic organisms require oxygen for survival, so as DO 

declines, the ability to sustain aquatic organisms decreases. 

Thus, a decrease in DO over time is generally considered a 

decrease in overall water quality, and the opposite also is true. 

The trend for DO was upward at three sites: the Tahquamenon River, lower Grand River, and lower St. Joseph River. 

The magnitudes of these upward trends are 2.7, 3.1, and 3.8 

percent per year, respectively (appendix 1).

The pH scale describes the hydrogen-ion activity in 

water. Waters with low pH are considered acidic, and waters 

with high pH are considered alkaline. The pH of a typical 

stream ranges between 5 and 9. A pH value of 7 is considered 

neutral: under natural (unaltered) conditions, however, the 

pH of stream water can be slightly acidic or slightly alkaline, 

depending on local environmental conditions. Trends in pH 

need to be evaluated in the context of the starting values at the 

beginning of the study. If the pH starts low and has an upward 

trend or starts high and has a downward trend, water quality 

could be considered improving. Upward trends in pH were 

detected at sites on the lower Muskegon, upper St. Joseph, 

and the Shiawassee Rivers (table 6). The percent increase per 

year for pH was 0.45 for the lower Muskegon River, 0.87 for 

the upper St. Joseph River, and 0.89 on the Shiawassee River 

(appendix 1). Despite the increase in pH, the median values 

for these sites and all others still remain between 9.0 and 6.5, 

which indicate acceptable water quality with respect to Rule 

53 of part 4 of Public Act 451 (Michigan Department of 

Environmental Quality, 2006b).

Table 5. Summary of trend-analysis results for Michigan study sites, 1999–2005.

Constituent Number of sites 

analyzed

Sites with 

upward trend

Sites with 

downward trend Sites with no trend

Major chemical constituents and physical properties

Chloride 28 7 1 20

Dissolved oxygen 28 3 0 25

pH 28 3 0 25

Turbidity 23 0 3 20

Specific conductance 28 1 1 26

Total suspended solids 15 1 0 14

Water temperature 28 0 1 27

Nutrients

Nitrite 26 5 1 20

Ammonia 24 1 3 20

Phosphorus 27 1 2 24

Total Kjeldahl nitrogen 28 1 2 25

Nitrate 25 0 1 24

Trace metals

Chromium 24 0 6 18

Copper 28 6 0 22

Lead 28 1 2 25

Mercury 28 1 0 27
Table 6. Trends for various physical properties analyzed at Michigan stream sites, 1999–2005.[▲, increasing trend with p-value less than or equal to 0.05; , increasing trend with p-value greater than 0.05 but less than 0.10; ▼, decreasing trend with p-value less than or trend with p-value greater than 0.05 but less than 0.10; ―, no trend detected; NA, trend not tested because of data limitations]

Watershed 

number Site Dissolved oxygen pH Turbidity Specific conductance Total suspe

solids 

1 Ontonagon River at Ontonagon ― ― ― ― ― 2 Menominee River at Menominee ― ― ― ― NA 3 Escanaba River at Wells ― ― ― ― NA 4 Sturgeon River at Nahma ― ― ▼ ― NA 5 Manistique River above Manistique ― ― NA ― NA 6 Tahquamenon River at Emerson ▲ ― ― ― NA7 Pine River near Charles ― ― ― ― ― 8 Cheboygan River at Cheboygan ― ― NA ― NA 9 Boardman River near Traverse City NA NA NA NA NA 

10 Manistee River at Parkdale ― ― ― ― 

11 Pere Marquette River at Scottville ― ― NA ― NA 

12 Muskegon River near Bridgeton ― NA ― NA 13 Muskegon River near Hersey ― ― ― ― NA 14 Grand River near Eastmanville ▲ ― ― ― ― 15 Grand River at Ionia ― ― ― ― ― 16 Kalamazoo River at New Richmond ― ― ― ― ― 17 Kalamazoo River near Augusta ― ― ― ― NA 18 St. Joseph River at St. Joseph ― ― ― ― 19 St. Joseph River at Mottville ― ▲ ― ― NA 20 River Raisin at Monroe ― ― ― ― 21 Huron River at Rockwood ― ― ― ― ― 22 River Rouge at River Rouge ― ― ― ― ― 23 Clinton River at Mt. Clemens ― ― ― ― ― 24 Black River at Port Huron ― ― ― ― ― 25 Flint River near Fosters ― ― ― ― ― 26 Cass River near Bridgeport ― ― ― ― ― 27 Shiawassee River near Fergus ― ▲ ▼ ― NA 28 Tittabawassee River near Saginaw ― ― ▼ ― 29 Saginaw River at Essexville NA NA NA NA NA 30 Au Sable River near Au Sable ― ― NA ― NA 31 Thunder Bay at Alpena NA NA NA NA NA 
16 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

Specific conductance describes the ability of a substance 

to conduct an electrical current. In water, there is a direct relation between specific conductance and the amount of dissolved 

ions present. Significant trends were detected at two sites, one 

an upward trend and one a downward trend. An upward trend 

of 5.66 percent per year was detected for the River Raisin site 

(appendix 1). A downward trend of 1.74 percent per year was 

detected for the Tittabawassee River site (appendix 1).

Turbidity is used to describe the clarity of water associated with how much suspended particulate matter is in the 

water. High turbidity values indicate a decrease in water 

clarity or an increase in the amount of suspended particulates 

in the water. High turbidity commonly is associated with poor 

water quality (Gray and Glysson, 2003). Downward trends 

were detected at sites on the Shiawassee, Tittabawassee, and 

Sturgeon Rivers (table 6). The magnitude of the downward 

trends at these sites is 16.3, 16.3, and 4.59 percent per year, 

respectively. No trends were detected at several sites where 

turbidity measured greater than 100 NTU (Grand River, Pine 

River, Clinton River, Flint River, River Raisin, Ontonagon 

River, and St. Joseph River). Even though there are no waterquality criteria for turbidity, turbidity is highly correlated to 

some other constituents, specifically, those that are transported 

in particulate or colloid form. So that as turbidity increases, so 

does the likelihood of these other constituent concentrations 

being increased and transported in these systems (Gray and 

Glysson, 2003). 

Water temperature was another physical property measured as part of this study. A significant trend was detected at 

1 of the 28 sites sampled. A downward trend in temperature of 

4.67 percent per year was detected at the Tahquamenon River 

(appendix 1).

TSS is similar to turbidity; however, this suspended 

material is measured by filtering a water sample and drying the filter to determine how much sediment gets filtered 

out. Similar to turbidity, high TSS typically is related to poor 

water quality. TSS concentrations usually are correlated with 

increased streamflow. A significant trend was detected at one 

site. An upward trend of 10.37 percent per year was detected 

at the Manistee River (appendix 1). Despite the upward trend 

in TSS for the Manistee River, the TSS concentration at this 

site was in the 25th percentile for all sites analyzed in the 

WCMP; the median TSS concentration was 10 mg/L. The 

Clinton, Pine, Flint, Grand, Cass, and Kalamazoo Rivers had 

median concentrations twice as high (greater than 20 mg/L). 

Because contaminants commonly are bound to these particles, 

high TSS values may indicate an increased probability of 

chemical contamination as well. The relation between TSS 

and other water-quality constituents is evaluated in more detail 

later in this report.

Trends in Chloride Concentrations

More sites had trends for chloride than any other constituent. Several potential sources of chloride exist in the 

environment. These sources may be naturally occurring like 

basin brines and dissolution of evaporite deposits (rock salt) 

or sources may be anthropogenic like road-deicing compounds 

and wastewater effluent. An increase in chloride is generally 

considered a decrease in water quality. Significant chloride 

trends were detected at eight sites; seven were upward trends 

and one was a downward trend (table 7). The seven sites 

with upward trends in chloride are on the upper and lower 

St. Joseph, upper Muskegon, lower Kalamazoo, Shiawassee, 

Menominee, and Clinton Rivers. The magnitudes of the trends 

detected at these seven sites are 2.62, 1.56, 6.34, 3.28, 3.76, 

3.94, and 4.63, respectively (appendix 1). The only downward 

trend detected for chloride was at the site on the Escanaba 

River, which had a downward trend of 9.35 percent per year 

(appendix 1). 

Chloride concentration in most streams varies temporally. By examining chloride data at the intensively monitored 

sites, it can be seen that chloride concentrations at a given 

site increase and decrease periodically through the year (fig. 

7). The degree of change is largest at sites with the highest 

chloride concentrations. There does not appear to be a similar 

pattern among these five sites, which suggests site-specific 

variables control the chloride concentration in the water. 

Chloride concentrations were inversely related to mean daily 

streamflow (fig. 8) at seven of the eight sites where a trend 

was detected. For the Clinton, Escanaba, Menominee, Shiawassee, Kalamazoo, and lower St. Joseph River sites, the 

highest concentrations of chloride typically were measured 

in July, August, and September when daily streamflow was 

lowest. 

Even though most trends for chloride concentrations in 

Michigan stream waters were upward, it is important to relate 

the observed chloride concentrations to water-quality criteria. 

The State of Michigan does not have a water-quality standard 

for chloride; however, the U.S. Environmental Protection 

Agency (USEPA) lists concentrations of chloride of 230 and 

860 mg/L for chronic and acute aquatic-life toxicity benchmarks, respectively (U.S. Environmental Protection Agency, 

1988). Throughout the study, the chronic aquatic-life toxicity 

criterion of 230 mg/L was exceeded eight times, and the acute 

aquatic-life toxicity criterion of 860 mg/L was never exceeded. 

All the samples greater than 230 mg/L were collected in urban 

areas in 2003–2005 during the months of March and April: 

five samples from the Clinton River site, two samples from 

the River Rouge site, and one sample from the Flint River 

site. These high chloride concentrations appear to be isolated events, and the long-term effect on these streams would 

require further evaluation to determine if increased chloride is 

a water-quality concern.
Table 7. Trend results for chloride at Michigan stream sites, 1999–2005.[▲, increasing trend with p-value less than or equal to 0.05; , increasing trend with p-value greater than 0.05 but less than 0.10; 

▼, decreasing trend with p-value less than or equal to 0.05; , decreasing trend 

with p-value greater than 0.05 but less than 0.10; ―, no trend detected; NA, trend not tested because of data limitations]

Watershed 

number Site Chloride

1 Ontonagon River at Ontonagon

―

2 Menominee River at Menominee3 Escanaba River at Wells

▼

4 Sturgeon River at Nahma

―

5 Manistique River above Manistique

―

6 Tahquamenon River at Emerson

―

7 Pine River near Charles

―

8 Cheboygan River at Cheboygan

―

9 Boardman River near Traverse City NA

10 Manistee River at Parkdale

―

11 Pere Marquette River at Scottville

―

12 Muskegon River near Bridgeton

―

13 Muskegon River near Hersey14 Grand River near Eastmanville

―

15 Grand River at Ionia

―

16 Kalamazoo River at New Richmond

▲

17 Kalamazoo River near Augusta

―

18 St. Joseph River at St. Joseph19 St. Joseph River at Mottville

▲

20 River Raisin at Monroe

―

21 Huron River at Rockwood

―

22 River Rouge at River Rouge

―

23 Clinton River at Mt. Clemens24 Black River at Port Huron

―

25 Flint River near Fosters

―

26 Cass River near Bridgeport

―

27 Shiawassee River near Fergus28 Tittabawassee River near Saginaw

―

29 Saginaw River at Essexville NA30 Au Sable River near Au Sable

―

31 Thunder Bay at Alpena NA

1999 2001 2002 2003 200

DA

TE

100101102103

234567923456792345679

CHLORIDE CONCENTRATION, IN MILLIGRAMS PER LITER

Kalamazoo River at

New Richmond

Muskegon River near BridgetonGrand River near EastmanvilleAu Sable River near Au SableClinton River at

Mt. Clemens

2000

Figure 7. Chloride concentrations over time for selected intensively moMichigan, 1999 through 2005.
2.0 2.3 2.5 2.8 3.0 3.3 3.5 3.8 LOG OF FLOW, IN CUBIC FEET PER SECOND 0204060 CHLORIDE CONCENTRATION, IN MILLIGRAMS PER LITER Escanaba River at Wells 1.5 2.0 2.5 3.0 3.5 4.0 0100 200 300 400 Clinton River at Mt. Clemens 1.9 2.4 

020406080 100 120 Shiaw

3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 02468 Menominee River at Menominee 2.8 3.0 3.2 3.4 3.6 3.8 2030405060 Kalamazoo River at New Richmond 2.4 2.6 2.8 3

0204060 Muskegon Rive

2.7 2.9 3.1 3.3 3.5 3.7 3.9 0102030 St. Joseph River at Mottville 2.8 3.0 3.2 3.4 

010203040 St. Jose

Figure 8. The relation between chloride concentration and streamflow at selected stream sites in Michigan, 1999 through 2005.
ESTREND Seasonal Kendall Test Results 19

Trends in Nutrient Concentrations

The constituents, commonly referred to as nutrients, 

analyzed for trends in this study were nitrite, ammonia, phosphorus, TKN, and nitrate. Phosphorus and nitrogen species 

may come from a variety of sources including wastewater 

effluent, common fertilizers, and atmospheric byproducts of 

combustion. Generally, high concentrations of nutrients are 

linked to degraded water quality, because these nutrients lead 

to increased algal growth and potentially to eutrophication of 

water bodies. 

Nitrogen

Nitrogen compounds are part of a large cycle involving 

the production and breakdown of nitrogen gas (N2), nitrite, 

nitrate, or ammonia compounds (fig. 9). Nitrogen-fixing bacteria in soils can take nitrogen gas and convert it to a form of 

nitrogen usable by plants. As plants die, ammonia is produced 

as a result of their decay. This ammonia is then used by bacteria to form nitrite, which in turn is transformed to nitrate by a 

different group of bacteria, and the cycle continues. Fertilizers 

commonly are applied in the form of nitrate to encourage plant 

growth. If fertilizers are applied in excess of plant needs, the 

excess can run off into streams or dissolve into groundwater 

and enter streams through base flow. In addition, wastewatertreatment practices may discharge large amounts of organic 

nitrogen and ammonia into the environment (not shown in 

figure 9). 

The recommended water-quality criteria for total nitrogen 

compounds in surface waters are dependent on the ecoregion 

in which the stream is located. Michigan is comprised of three 

different USEPA Ecoregional level III Ecoregions (U.S. Environmental Protection Agency, 2000). With the exception of the 

Traverse Bay Watershed, most of the northern Lower Peninsula and the entire Upper Peninsula was categorized as Ecoregion VIII. Most of the central and southern Lower Peninsula, 

including the Traverse Bay Watershed, makes up Ecoregion 

VII. The Saginaw Bay Watershed and Lake Erie Watershed 

areas are characterized as Ecoregion VI. Each ecoregion has a 

USEPA recommended water-quality criteria for nutrients 

specific to that ecoregion (U.S. Environmental Protection 

Agency, 2002, table 8). These criteria were developed as guidance on a national scale to reduce or prevent eutrophication of 

the nation’s water. Michigan is in the process of developing 

state nutrient criteria for future use.

Total nitrogen (TN) concentrations include the sum of 

TKN, nitrate, and nitrite. The recommended TN criterion was 

exceeded on the basis of the nitrate concentration alone in 

approximately 19 percent of the samples. Only the Cheboygan and Au Sable River sites met TN criteria for all samples. 

Median nitrate concentrations exceeded the recommended 

Ecoregion TN criteria at the Kalamazoo, Grand, Raisin, Cass, 

Flint, St. Joseph, Black, Shiawassee, and Clinton River sites. 

Trends for nitrite were the most commonly detected 

trends of the different nutrients tested (table 9). Five sites 

had upward trends, and one site had a downward trend. The 

upward nitrite trends at the Manistee, Clinton, upper Muskegon, Black, and Ontonagon River sites are 4.2, 10.9, 13.1, 

19.9, and 24.8 percent per year, respectively (appendix 1). 

The Au Sable River site had a downward trend of 0.02 percent 

per year (appendix 1). 

Trends in ammonia were detected at four sites (table 9). 

The lower Grand River site had an upward trend of 5.9 percent 

per year (appendix 1). The other three sites that had downward 

trends were the Shiawassee, upper St. Joseph, and Manistique 

Rivers. The magnitudes of the downward trends were 18.6, 

9.8, and 8.8 percent per year, respectively (appendix 1). 

TKN is defined as the concentration of the sum of 

organic nitrogen, ammonia, and ammonium ion in solution. 

An upward trend of 4.55 percent per year was detected at the 

Clinton River site (table 9) (appendix 1). Downward trends of 

3.7 and 2.9 percent per year were detected at sites on the Tittabawassee and Manistique Rivers, respectively (appendix 1). 

Table 8. Water-quality criteria for total phosphorus and total 

nitrogen for U.S. Environmental Protection Agency ecoregions 

in Michigan.

[USEPA, U.S. Environmental Protection Agency; mg/L, miligrams per liter]

USEPA ecoregion Total phosphorus 

(mg/L)

Total nitrogen 

(mg/L)

VI 0.076 2.18

VII 0.033 0.54

VIII 0.01 0.38

Figure 9. Schematic representation of the nitrogen cycle.

(Wastewater discharge and organic nitrogen not shown.)

Ammonia

Nitrate

Nitrite

Bacteria

Bacteria

Bacteria

Plant 

decay

Fertilizers

Bacteria

Ammonia

Nitrate

Nitrite

Nitrogen gas

Bacteria

Bacteria

Bacteria

Plant 

decay

Fertilizers

Bacteria
Table 9. Trend results for nutrients at Michigan stream sites, 1999–2005. [▲, increasing trend with p-value less than or equal to 0.05; , increasing trend with p-value greater than 0.05 but less than 0.10; ▼, decreasing trend w0.05; , decreasing trend with p-value greater than 0.05 but less than 0.10; ―, no trend detected; NA, trend not tested because of data limitations] Watershed number Site Total Kjeldahl nitrogen Ammonia Nitrite Nitrate 

1 Ontonagon River at Ontonagon ― ― NA 2 Menominee River at Menominee ― ― ― ― 3 Escanaba River at Wells ― ― ― ― 4 Sturgeon River at Nahma ― ― ― ― 5 Manistique River above Manistique ▼ ▼ ― ― 6 Tahquamenon River at Emerson ― ― ― ― 7 Pine River near Charles ― ― NA NA 8 Cheboygan River at Cheboygan ― ― NA NA 9 Boardman River near Traverse City NA NA NA NA 

10 Manistee River at Parkdale ― ― ― 11 Pere Marquette River at Scottville ― ― ― ― 12 Muskegon River near Bridgeton ― ― ― ― 13 Muskegon River near Hersey ― ― ― 14 Grand River near Eastmanville ― ― ― 15 Grand River at Ionia ― ― ― ― 16 Kalamazoo River at New Richmond ― ― ― ― 17 Kalamazoo River near Augusta ― ― ― ― 18 St. Joseph River at St. Joseph ― ― ― ― 19 St. Joseph River at Mottville ― ▼ ― ― 20 River Raisin at Monroe ― NA ― ― 21 Huron River at Rockwood ― ― ― ― 22 River Rouge at River Rouge ― ― ― ― 23 Clinton River at Mt. Clemens ― ▼ 24 Black River at Port Huron ― NA ― 25 Flint River near Fosters ― NA ― ― 26 Cass River near Bridgeport ― NA ― ― 27 Shiawassee River near Fergus ― ▼ ― ― 28 Tittabawassee River near Saginaw ▼ ― ― ― 29 Saginaw River at Essexville NA NA NA NA 30 Au Sable River near Au Sable ― ― ▼ ― 31 Thunder Bay at Alpena NA NA NA NA 
ESTREND Seasonal Kendall Test Results 21

Only the Clinton River site had a significant downward 

trend in nitrate with a magnitude of 2.57 percent per year. 

The Clinton River at Mt. Clemens sampling site is in an urban 

setting downstream of major permitted wastewater discharges. 

In the headwaters of the Clinton River Watershed, the land use 

is more agriculture and residential. This sampling site, close to 

the mouth of the Clinton River, is influenced locally by heavy 

urbanization but also is affected by upstream agricultural and 

residential inputs. Despite a downward trend in nitrate, the 

Clinton River did show upward trends in concentrations of 

nitrite and TKN. Median concentrations for TKN, nitrate, and 

nitrite at this site were 1.03, 1.57, and 0.039 mg/L as nitrogen, 

respectively. Therefore, even though the downward nitrate 

trend appears to be an improvement, the TN concentration 

at this site is still a concern. High concentrations of TKN 

commonly are measured in wastewater effluent. If wastewater effluent were the primary contributor of TKN at this site, 

the highest concentrations would be expected during lower 

streamflow. This is not the case (fig. 10); TKN peaks correspond to increases in streamflow. 

In contrast to TKN, the peaks in nitrate concentration 

correspond to decreases in streamflow (fig. 11). TKN and 

ammonia are not very mobile and commonly are attached 

to particles introduced into surface water from runoff or 

direct discharge of waste into streams. However, nitrate and 

nitrite are easily dissolved and are very mobile in surface and 

groundwater. Because nitrate and nitrite are by-products of 

TKN degradation, they come from the same source but differ 

in their transport mechanism.

 Although there was no statistical trend for TSS, there 

does appear to be a relation between the concentrations of 

TKN and nitrate and the amount of TSS for the Clinton River 

sampling site (fig. 12). TKN increases with increased TSS and 

nitrate decreases with increased TSS. There is also a direct 

relation between daily streamflow and TSS at this site (fig. 

13). This relation suggests that the increased concentrations 

of TKN are a result of increased runoff during precipitation 

events in the watershed. These precipitation events lead to 

high streamflow that dilute nitrate concentrations in the water. 

The high flows may also lead to increased sediment load to 

the stream from erosion or resuspension of bed sediment. 

This might also indicate that nitrate concentrations are either 

associated with groundwater discharging to the stream and (or) 

direct discharge of wastewater effluent.

Figure 10. Concentration of Total Kjeldahl nitrogen and streamflow, 2000 through 2005, Clinton River, Michigan.

2000 2001 2002 2003 2004 2005

0

1

2

3

4

TOTAL KJELDAHL NITROGEN, IN MILLIGRAMS PER LITE

R

0

4000

8000

12000

16000

DAILY STREAMFLOW, IN CUBIC FEET PER SECOND

Total Kjeldahl nitrogen

Daily streamflow
22 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

Figure 11. Concentration of nitrate and streamflow, 2000 through 2005, Clinton River, Michigan.

2000 2001 2002 2003 2004 2005

0

1

2

3

4

NITRA

TE IN

MILLIGRA

MS PER LITER AS NITRO

GEN

0

4000

8000

12000

16000

D

AILY STREA

MFLO

W, IN CU

BIC FEET PER SECO

N

D

Nitrate as nitrogen

Daily streamflow

0 1 2 3

LOG TOTAL SUSPENDED SOLIDS CONCENTRATION, IN MILLIGRAMS PER LITER

-0.2

0.0

0.2

0.4

0.6

0.8

Total Kjeldahl nitrogen

Nitrate as nitrogen

LOG TOTAL 

KJELDAHL NITROGEN

AND NITRATE AS NITROGEN

CONCENTRATIONS, IN MILLIGRAMS PER LITER

R2= 0.3573

R2

= 0.5887

Figure 12. The relations between concentrations of total Kjeldahl nitrogen and nitrate and total suspended solids 

for the Clinton River, Michigan.
ESTREND Seasonal Kendall Test Results 23

1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

LOG STREAMFLOW, IN CUBIC FEET PER SECOND

0.00

0.75

1.50

2.25

3.00

LOG TOTAL SUSPENDED SOLIDS CONCENTRATION,

 IN MILLIGRAMS PER LITER

R

2

=0.5595

0.0 0.5 1.0 1.5 2.0 2.5 3.0

LOG TOTAL SUSPENDED SOLIDS CONCENTRATION, IN MILLIGRAMS PER LITER

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

LOG PHOSPHORUS CONCENTRATION, IN MILLIGRAMS PER LITER

R2= 0.5926

Figure 13. The relation between total suspended solids and streamflow for the Clinton River, Michigan.

Figure 14. Relation between concentration of phosphorus and total suspended solids in selected Michigan streams. 
24 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

Phosphorus

Like nitrogen, high levels of phosphorus can cause 

excessive growth of undesirable plants and algae, which lead 

to water-quality degradation. The USEPA recommended 

criteria for TP in streams for USEPA Ecoregions in Michigan 

are shown in table 8. Like TN, TP concentrations in samples 

collected for the WCMP exceeded the recommended criteria 

approximately 33 percent of the time. Ten sites consistently 

exceeded the TP criteria: the Manistee River, Tahquamenon 

River, Pine River, St. Joseph River (2 sites), Cass River, Grand 

River (2 sites), Flint River, and Clinton River. Significant 

trends in phosphorus were detected at three sites across the 

state. One site had an upward trend, and two sites had downward trends. An upward trend in phosphorus of 4.28 percent 

per year was detected at the Manistee River site (appendix 1). 

Downward phosphorus trends were detected at the Tittabawassee River and Pere Marquette River sites with magnitudes of 

7.2, and 5.9 percent per year, respectively (appendix 1, table 

9). 

Common sources of phosphorus include weathering of 

natural soils and rocks, runoff of excess fertilizer applications (agricultural and residential), and municipal wastewater 

discharges. Phosphorus is easily sorbed to soil particles such 

as sediment; therefore, phosphorus concentrations are usually directly related to TSS concentrations. As shown in figure 

14, TSS and phosphorus are positively correlated indicating 

phosphorus is typically associated with and transported by 

particulates at the 10 sites that exceed the TP criteria. This 

may be from land-surface runoff in agriculture areas or wastewater discharges from urban areas. Interestingly, even though 

concentrations are generally lower at sites in less-developed 

areas (little agricultural or urban inputs), these sites occasionally have observed concentrations that exceed recommended 

criteria, suggesting a possible geologic or wildlife component 

to phosphorus in Michigan streams. 

Trends in Trace Metals Concentrations

Four trace metals—chromium, copper, lead, and mercury— were analyzed for trends in this study. Trace metals 

generally are associated with industrial waste, but sources 

also may include wastewater effluent as well as atmospheric 

deposition, in the case of mercury. Generally, an increase in 

concentrations of trace metals indicates a decline in water 

quality.

Statistically significant downward trends for chromium 

were detected at six sites (table 10). Trends were detected at 

sites on the Escanaba, Shiawassee, lower St. Joseph, lower 

Kalamazoo, lower Grand, and Tahquamenon Rivers. The magnitudes of the downward trends were 17.8, 16.1, 13.8, 13.3, 

13.5, and 11.2 percent per year, respectively (appendix 1). The 

highest chromium concentration detected (32.7 μg/L) was at 

the Clinton River site.

Upward trends for copper were detected at six sites 

across the state (table 10), at the lower St. Joseph, upper and 

lower Muskegon, Sturgeon, Rouge, and Au Sable Rivers. 

Magnitudes of the upward trends detected for copper at these 

sites were 3.4, 6.7, 4.8, 5.3, 8.8, and 14.1 percent per year, 

respectively (appendix 1). 

The estimated trends may not be unusual, because copper 

is an abundant and naturally occurring element in the Earth’s 

crust. Copper is essential to all plants and animals; however, 

high concentrations of copper can be toxic to aquatic life (U.S. 

Environmental Protection Agency, 2007). Copper can be introduced to streams from mining practices, discharge of municipal wastes, addition to animal feeds for disease prevention, 

and also as a pesticide for the control of plant pathogens (such 

as Dutch Elm disease), algae, and slugs (Extension Toxicology 

Network, 1996). 

Trends in lead concentrations were detected at three sites 

(table 10). One trend was upward, and the other two were 

downward. An upward trend of 5.49 percent per year was 

detected at the Manistee River site (appendix 1). However, 

the highest concentration measured at this site was only 0.298 

μg/L (appendix 1). The downward trends were detected at the 

Shiawassee and Menominee River sites with magnitudes of 

8.6 and 5.6 percent per year, respectively (appendix 1). 

Only one significant trend was detected for mercury 

(table 10). This trend was an upward trend of 9.63 percent 

per year detected at the Ontonagon River site (appendix 1). 

The median mercury concentration, for 21 of the 28 sites, was 

greater than 1.3 ng/L (Michigan Department of Environmental 

Quality, 2007). Sources of mercury contamination include 

wastewater discharges particularly from industrial areas and 

also atmospheric deposition. 

Spatial Distribution of Trends

One of the primary objectives of the WCMP is to determine the status of water quality throughout Michigan. Most of 

the WCMP sampling sites are at the mouths of major watersheds and are useful for indicating water-quality conditions for 

individual watersheds. However, comparison of constituent 

trends between watersheds is useful to determine if there were 

any spatial water-quality patterns throughout the state (figs. 

15–18).

Several trends were detected in watersheds that drain into 

Lake Michigan. Chloride concentrations appear to be increasing in the St. Joseph and Kalamazoo River watersheds in the 

southwestern part of the state (fig. 16). One potential source 

of chloride in the St. Joseph and Kalamazoo River watersheds 

is that this region receives substantial amounts of lake-effect 

snowfall in the winter months, which might indicate increased 

road-salt application and runoff. DO is also increasing for two 

watersheds in western Michigan (fig. 15). In contrast, increasing DO is an indicator that water quality is improving in these 

watersheds. Also, there appears to be a decrease in chromium 

for most of the western Michigan watersheds (fig. 18). The 

possible cause for this decrease is uncertain at this time. 
ESTREND Seasonal Kendall Test Results 25

Table 10. Trend results for trace metals at selected Michigan stream sites, 1999–2005. 

[▲, increasing trend with p-value less than or equal to 0.05; , increasing trend with p-value greater than 0.05 but less than 0.10; ▼, decreasing trend with 

p-value less than or equal to 0.05; , decreasing trend with p-value greater than 0.05 but less than 0.10; ―, no trend detected; NA, trend not tested because of 

data limitations]

Watershed 

number Site Chromium Copper Lead Mercury

1 Ontonagon River at Ontonagon ― ― ― ▲

2 Menominee River at Menominee ― ― ―

3 Escanaba River at Wells ▼ ― ― ―

4 Sturgeon River at Nahma ― ― ―

5 Manistique River above Manistique ― ― ― ―

6 Tahquamenon River at Emerson ― ― ―

7 Pine River near Charles ― ― ― ―

8 Cheboygan River at Cheboygan NA ― ― ―

9 Boardman River near Traverse City NA NA NA NA

10 Manistee River at Parkdale ― ― ―

11 Pere Marquette River at Scottville ― ― ― ―

12 Muskegon River near Bridgeton NA ― ―

13 Muskegon River near Hersey NA ― ―

14 Grand River near Eastmanville ▼ ― ― ―

15 Grand River at Ionia ― ― ― ―

16 Kalamazoo River at New Richmond ▼ ― ― ―

17 Kalamazoo River near Augusta ― ― ― ―

18 St. Joseph River at St. Joseph ▼ ▲ ― ―

19 St. Joseph River at Mottville ― ― ― ―

20 River Raisin at Monroe ― ― ― ―

21 Huron River at Rockwood ― ― ― ―

22 River Rouge at River Rouge ― ― ―

23 Clinton River at Mt. Clemens ― ― ― ―

24 Black River at Port Huron ― ― ― ―

25 Flint River near Fosters ― ― ― ―

26 Cass River near Bridgeport ― ― ― ―

27 Shiawassee River near Fergus ▼ ― ―

28 Tittabawassee River near Saginaw ― ― ― ―

29 Saginaw River at Essexville NA NA NA NA

30 Au Sable River near Au Sable NA ― ―

31 Thunder Bay at Alpena NA NA NA NA

Saginaw Bay (on the eastern side of the state) is heavily 

influenced by the water quality of several contributing watersheds. These contributing watersheds were watersheds 26–28, 

represented by the sites on the Flint, Cass, Shiawassee, and 

Tittabawassee Rivers respectively. Two of the measured watersheds (Shiawassee and Tittabawassee) in this region show a 

downward trend in turbidity (fig. 15). Decreasing turbidity 

might suggest that other chemicals associated with sediment 

transport, which were not sampled as part of this study, may 

also be decreasing. It should be noted that the area in the eastcentral Lower Peninsula commonly referred to as the thumb 

area of Michigan (fig. 1) is not well represented in this study. 

This area has a large agricultural land-use component that may 

be contributing nutrients to Saginaw Bay and Lake Huron.

Other regional trends were observed in this study. For 

example, copper concentrations appear to be increasing in the 

northern Lower Peninsula. Nitrite is increasing in both the 

Black River and Clinton River Watersheds (fig.17). The Black 

River has a large agricultural land-use component, and the 

Clinton River is dominated by urban land-use effects. Both 

of these watersheds are tributaries to Lake St. Clair and thus 

influence the water quality of Lake St. Clair. 
26 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

Dissolved oxygen pH

Water temperature

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

9

10

12

22

11 28

13

27

15

24

17

Site location

EXPLANATION

Increasing trend with p-value less than or equal to 0.05

Increasing trend with p-value greater than 0.05 but less than 0.1

Decreasing trend with p-value greater than 0.05 but less than 0.1

Insufficient data for trend analysis

No trend

Integrator

Intensive

Watershed

0 50 100 MILES

0 50 10 0

1 Watershed number

Specific conductance

16

5

18 19

2

1

4 3

6

30

23

29

14

20

21

26

25

31

8

7

9

10

12

22

28

11

13

27

15

24

17

9 9

KILOMETERS

Basemap: State and County boundaries from the Michigan Geographic Framework, 2003.

Watershed boundaries from 1:250,000 Hydrologic Unit Codes (U.S. Geological Society, 1994) and split as necessary using upstream 

1:24,000 watershed boundaries (Michigan Department of Environmental Quality, 1998).

Figure 15. Trend results for dissolved oxygen, pH, water temperature, and specific conductance by Michigan watershed.
ESTREND Seasonal Kendall Test Results 27

Total suspended solids

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

Chloride

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

Turbidity

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

Phosphorus

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

9 9

9 9

Decreasing trend with p-value less than or equal to 0.05 Site location

EXPLANATION

Increasing trend with p-value less than or equal to 0.05

Increasing trend with p-value greater than 0.05 but less than 0.1

Decreasing trend with p-value greater than 0.05 but less than 0.1

Insufficient data for trend analysis

No trend

Integrator

Intensive

Watershed

0 50 100 MILES

0 50 10 0

1 Watershed number

KILOMETERS

Basemap: State and County boundaries from the Michigan Geographic Framework, 2003.

Watershed boundaries from 1:250,000 Hydrologic Unit Codes (U.S. Geological Society, 1994) and split as necessary using upstream 

1:24,000 watershed boundaries (Michigan Department of Environmental Quality, 1998).

Figure 16. Trend results for turbidity, total suspended solids, chloride, and phosphorus by Michigan watershed.
28 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

Figure 17. Trend results for ammonia, nitrate, total Kjeldahl nitrogen, and nitrite by Michigan watershed.

9 9

9

Ammonia

Total Kjeldahl nitrogen Nitrite

Nitrate

16

5

18 19

2

1

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

16

5

18 19

1

2

4

3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

28 11

13

27

15

24

17

16

5

18 19

1

2

4

3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

28 11

13

27

15

24

17

9

Site location

EXPLANATION

Increasing trend with p-value greater than 0.05 but less than 0.1

Decreasing trend with p-value less than or equal to 0.05 

Insufficient data for trend analysis

No trend

Integrator

Intensive

Watershed

0 50 100 MILES

0 50 10 0

1 Watershed number

KILOMETERS

Basemap: State and County boundaries from the Michigan Geographic Framework, 2003.

Watershed boundaries from 1:250,000 Hydrologic Unit Codes (U.S. Geological Society, 1994) and split as necessary using upstream 

1:24,000 watershed boundaries (Michigan Department of Environmental Quality, 1998).
ESTREND Seasonal Kendall Test Results 29

9 9

9 9

Chromium Copper

Lead Mercury

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

16

5

18 19

1

2

4 3

6

30

23

29

14

20

21

26

25

31

8

7

10

12

22

11 28

13

27

15

24

17

0 50 100 MILES

0 50 10 0 KILOMETERS

Basemap: State and County boundaries from the Michigan Geographic Framework, 2003.

Watershed boundaries from 1:250,000 Hydrologic Unit Codes (U.S. Geological Society, 1994) and split as necessary using upstream 

1:24,000 watershed boundaries (Michigan Department of Environmental Quality, 1998).

Decreasing trend with p-value less than or equal to 0.05 Site location

EXPLANATION

Increasing trend with p-value less than or equal to 0.05

Increasing trend with p-value greater than 0.05 but less than 0.1

Decreasing trend with p-value greater than 0.05 but less than 0.1

Insufficient data for trend analysis

No trend

Integrator

Intensive

Watershed

1 Watershed number

Figure 18. Trend results for chromium, copper, lead, and mercury by Michigan watershed.
30 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

Summary and Conclusions

In 1998, the Michigan Department of Environmental 

Quality (MDEQ) and the U.S. Geological Survey (USGS) 

began a long-term monitoring program to evaluate the water 

quality of most watersheds in Michigan. Major goals of the 

program were to identify streams exceeding or not meeting 

water-quality standards and to assess whether measured values 

of physical properties and concentrations of chemical constituents reflecting water quality in these streams were increasing 

or decreasing over time. As part of this program, water-quality 

data collected over 1998–2005 were analyzed to identify 

potential trends and to provide an understanding of changes 

in water quality. In all, 16 properties and constituents were 

analyzed for 28 sites across Michigan. 

The uncensored Seasonal Kendall test within the 

ESTREND program was used for analysis of the various 

water-quality data. Variability in measured properties and 

constituent concentrations associated with temporal and 

streamflow-related factors are accounted for in ESTREND. In 

addition, missing record, censored data, and a non-normal distribution of data can be accommodated by use of this nonparametric trend-testing technique. For all properties and constituents tested at the selected sites, data sets spanned a minimum 

of 5 years of record and contained less than 5 percent censored 

values, and at least 30 percent of the values were within the 

beginning one-fifth and ending one-fifth of the selected period. 

Upward trends indicated an increase in a measured property or 

constituent concentration over time, whereas downward trends 

indicated a decrease.

The most prevalent trend detected throughout the state 

was for chloride concentration; trends were detected at 8 of 

the 28 sites, with upward trends at 7 sites and a downward 

trend at 1 site. Among the trace metals examined in this study, 

chromium showed a prevalence of downward trends, indicating an overall improvement in water quality with regards to 

chromium. This improvement may be the result of changes 

in industrial practices over time. In contrast, the trace metal 

copper had an upward trend at six sites. Among the nutrients 

examined in this study, trends in nitrite were the most commonly detected. Upward trends for nitrite were detected at five 

sites on the Manistee, Clinton, upper Muskegon, Black, and 

Ontonagon Rivers. 

Although trends in constituent concentrations were not 

detected at all sites, the data collected as part of this project 

were still valuable in evaluating the quality of streams in the 

State of Michigan. This report identified sites where no statistically significant trends were detected but where constituent 

concentrations did not meet water-quality criteria. At several 

sites, nitrogen and phosphorus were measured at concentrations much higher than USEPA recommendations for nutrients 

in water. High nitrogen concentrations were measured at several sites in watersheds with agricultural inputs. Phosphorus 

also was detected at high concentrations in several watersheds 

with substantial areas of urban and agricultural land use. 

Trend analysis for water-quality data collected during 

1998–2005 provided an overview of how water quality may 

be changing over time. In addition, this analysis established 

a baseline against which to evaluate future changes in water 

quality. Many factors may be affecting changes in water quality, and trend analyses served to assist in identifying some 

of these factors. Further site-specific investigations would 

be needed to better address how policy, land-use, climatic, 

wastewater, and agricultural issues or practices are affecting 

the water quality in the various watersheds.

References Cited

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Stream water quality: U.S. Geological Survey Water-Supply 

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Extension Toxicology Network, 1996, Copper sulfate: 

accessed July 1, 2008, at http://extoxnet.orst.edu/pips/

coppersu.htm

Gray, J.R., and Glysson, G.D., 2003, Proceedings of the 

federal interagency workshop on turbidity and other 

sediment surrogates, April 30–May2, 2002, Reno, Nevada: 

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September 11, 2008, at http://pubs.usgs.gov/circ/2003/

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Helsel, D.R., and Hirsch, R.M., 2002, Statistical methods in 

water resources: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 4, chap. A3, 524 p.

Hirsch, R.M., Alexander, R.B., and Smith, R.A., 1991, 

Selection of methods for the detection and estimation of 

trends in water quality: Water Resources Research, v. 29, 

no. 5, p. 803–813.

Hirsch, R.M., Slack, J.R., and Smith, R.A, 1982, Techniques 

of trend analysis for monthly water quality data: Water 

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at http://www.deq.state.mi.us/documents/deq-swq-gleas9899trendreport.pdf

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Michigan Department of Environmental Quality, 2003, Michigan water chemistry monitoring, 2001 report: MI/DEQ/

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at http://www.michigan.gov/documents/deq/wb-swas-rulespart4_254149_7.pdf

Michigan Department of Environmental Quality, 2007, Rule 

57 water quality values: accessed October 2, 2007, at 

http://www.michigan.gov/deq/0,1607,7-135-

3313_3686_3728-11383--,00.html

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tributaries, 1998–2005 report: MI/DEQ/WB-08/014, 

accessed June 20, 2008, at http://www.michigan.gov/

documents/deq/wb-swas-9805tribreport_222804_7.pdf

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chemistry: accessed June 20, 2008, at http://www.michigan.

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v. 116, no. 13, 29 p.

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v. 117, no. 13, 33 p.

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v. 119, no. 13, 35 p.

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New Jersey’s modernized ambient chemical monitoring 

network: Trenton, N.J., Division of Watershed Management, 

12 p.

Schertz, T.L., Alexander, R.B., and Ohe, D.J., 1991, 

The computer program Estimate Trend (ESTREND), 

a system of detection of trends in water quality data: 

U.S. Geological Survey Water-Resources Investigation 

Report 91–4040, 63 p.

Syed, A.U., and Fogarty, L.R., 2005, Trends in surface-water 

quality at selected National Stream Quality Accounting 

Network (NASQAN) Stations, in Michigan: 

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2005–5158, 38 p., at http://pubs.usgs.gov/sir/2005/5158 

Team for Evaluating the Wisconsin Water-Monitoring 

Network, 1998, An integrated water-monitoring network for 

Wisconsin: Madison, Wis., University of Wisconsin Water 

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usgs.gov/pubs/FS-048-98/FS-048-98.pdf

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www.epa.gov/waterscience/criteria/library/ambientwqc/

chloride1988.pdf

U.S. Environmental Protection Agency, 2000, Ambient 

water quality criteria recommendations: information 

supporting the development of state and tribal nutrient criteria for rivers and streams in nutrient Ecoregion III; 

EPA 822-B-00-016, 20 p., accessed March 30, 2009, at 

http://www.epa.gov/waterscience/criteria/library/index.html

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2009, at http://www.epa.gov/waterscience/criteria/nutrient/

ecoregions/files/sumtable.pdf

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aquatic life copper criteria: accessed July 1, 2008, at http://

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32 Analysis of Water-Quality Trends for Selected Streams in the Water-Chemistry Monitoring Program, Michigan, 1998–2005

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Units of the United States: available online at http://water.

usgs.gov/GIS/metadata/usgswrd/XML/huc250k.xml

Wilde, F.D., and Radtke, D.B., August 2005, General information and guidelines (version 1.2): 

U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 9, chap. A6, section 6.0, accessed 

April 25, 2008, at http://water.usgs.gov/owq/FieldManual/

Chapter6/Ch6_contents.html
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued[mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested]

Watershed 

number Site

USGS 

station 

number

Constituent

Number 

of 

samples 

collected

Number of 

censored 

results

Minimum 

concentration

Median 

concentration

Maximum 

concentration

Years 

of data 

used

S

1 Ontonagon River at Ontonagon 04040018 Ammonia

 (mg/L as N)

23 0 0.003 0.008 0.024 6 

1 Ontonagon River at Ontonagon 04040018 Chloride (mg/L) 23 0 2 3 7 6 1 Ontonagon River at Ontonagon 04040018 Chromium (μg/L) 23 0 0.331 0.899 3.54 6 1 Ontonagon River at Ontonagon 04040018 Copper (μg/L) 23 0 1.12 3.29 7.17 6 1 Ontonagon River at Ontonagon 04040018 Dissolved oxygen (mg/L) 23 0 6.5 8.6 13 6 1 Ontonagon River at Ontonagon 04040018 Lead (μg/L) 23 0 0.0605 0.26 1.16 6 1 Ontonagon River at Ontonagon 04040018 Mercury (ng/L) 23 1 0.3 2.18 8.35 6 1 Ontonagon River at Ontonagon 04040018 Nitrate (mg/L as N) 20 4 0.001 0.023 0.21 -- 1 Ontonagon River at Ontonagon 04040018 Nitrite (mg/L as N) 23 0 0.001 0.006 0.019 6 1 Ontonagon River at Ontonagon 04040018 pH 23 0 7.1 7.66 8 6 1 Ontonagon River at Ontonagon 04040018 Total phosphorus (mg/L as P) 23 0 0.015 0.037 0.167 6 1 Ontonagon River at Ontonagon 04040018 Specific conductance (μS/cm) 23 0 59.6 144 179 6 1 Ontonagon River at Ontonagon 04040018 Total Kjehldahl nitrogen 

(mg/L as N)

23 0 0.22 0.4 0.73 6 

1 Ontonagon River at Ontonagon 04040018 Total suspended solids (mg/L) 23 0 4 13 130 6 1 Ontonagon River at Ontonagon 04040018 Turbidity (NTU) 23 0 7.5 23 130 6 1 Ontonagon River at Ontonagon 04040018 Water temperature (°C) 23 0 1.7 16.4 27.6 6 2 Menominee River at Menominee 04067648 Ammonia 

(mg/L as N)

31 0 0.004 0.016 0.047 6 

2 Menominee River at Menominee 04067648 Chloride (mg/L) 31 0 3 6 9 6 2 Menominee River at Menominee 04067648 Chromium (μg/L) 31 0 0.049 0.257 0.976 6 2 Menominee River at Menominee 04067648 Copper (μg/L) 31 0 0.489 0.884 1.64 6 2 Menominee River at Menominee 04067648 Dissolved oxygen (mg/L) 31 0 5.6 9.3 12.9 6 2 Menominee River at Menominee 04067648 Lead (μg/L) 31 0 0.0506 0.139 0.851 6 2 Menominee River at Menominee 04067648 Mercury (ng/L) 30 1 0.45 2.755 12.1 6 2 Menominee River at Menominee 04067648 Nitrate (mg/L as N) 29 2 0.002 0.071 0.27 6 2 Menominee River at Menominee 04067648 Nitrite (mg/L as N) 31 0 0.001 0.004 0.007 6 2 Menominee River at Menominee 04067648 pH 31 0 7.2 7.8 8.3 6 2 Menominee River at Menominee 04067648 Total phosphorus (mg/L as P) 31 0 0.015 0.033 0.1 6 2 Menominee River at Menominee 04067648 Specific conductance (μS/cm) 31 0 102 243 308 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued [mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested] Watershed number Site USGS station number Constituent Number of samples collected Number of censored results Minimum concen- tration Median concen- tration Maximum concen- tration Years of data used S

2 Menominee River at Menominee 04067648 Total Kjehldahl nitrogen (mg/L as N) 31 0 0.31 0.48 0.84 6 2 Menominee River at Menominee 04067648 Total suspended solids (mg/L) 31 8 4 4 41 -- 2 Menominee River at Menominee 04067648 Turbidity (NTU) 31 2 1 3 15 6 2 Menominee River at Menominee 04067648 Water temperature (°C) 31 0 4 17.5 26 6 3 Escanaba River at Wells 040590345 Ammonia (mg/L as N) 47 0 0.024 0.056 0.135 7 3 Escanaba River at Wells 040590345 Chloride (mg/L) 47 0 5 18 61 7 3 Escanaba River at Wells 040590345 Chromium (μg/L) 47 0 0.129 0.604 1.29 7 3 Escanaba River at Wells 040590345 Copper (μg/L) 47 0 0.508 0.841 2.33 7 3 Escanaba River at Wells 040590345 Dissolved oxygen (mg/L) 45 0 5.1 8.6 13.7 7 3 Escanaba River at Wells 040590345 Lead (μg/L) 47 0 0.109 0.153 0.765 7 3 Escanaba River at Wells 040590345 Mercury (ng/L) 47 1 0.45 2.9 55.357 7 3 Escanaba River at Wells 040590345 Nitrate (mg/L as N) 47 0 0.067 0.118 0.42 7 3 Escanaba River at Wells 040590345 Nitrite (mg/L as N) 47 0 0.004 0.012 0.054 7 3 Escanaba River at Wells 040590345 pH 46 0 6.8 7.815 8.6 7 3 Escanaba River at Wells 040590345 Total phosphorus (mg/L as P) 47 0 0.006 0.038 0.19 7 3 Escanaba River at Wells 040590345 Specific conductance (μS/cm) 46 0 154 351.5 714 7 3 Escanaba River at Wells 040590345 Total Kjehldahl nitrogen (mg/L as N) 47 0 0.41 0.6 1.06 7 3 Escanaba River at Wells 040590345 Total suspended solids (mg/L) 47 15 1 4 19 -- 3 Escanaba River at Wells 040590345 Turbidity (NTU) 34 0 2.6 4.35 12 6 3 Escanaba River at Wells 040590345 Water temperature (°C) 45 0 1.1 15.6 26.7 7 4 Sturgeon River at Nahma 04057521 Ammonia (mg/L as N) 31 0 0.008 0.019 0.061 6 4 Sturgeon River at Nahma 04057521 Chloride (mg/L) 31 0 2 2 3 6 4 Sturgeon River at Nahma 04057521 Chromium (μg/L) 31 0 0.092 0.344 0.74 6 4 Sturgeon River at Nahma 04057521 Copper (μg/L) 31 0 0.206 0.418 0.8 6 4 Sturgeon River at Nahma 04057521 Dissolved oxygen (mg/L) 31 0 6.5 9.2 12.1 6 4 Sturgeon River at Nahma 04057521 Lead (μg/L) 31 0 0.0348 0.187 0.551 6 4 Sturgeon River at Nahma 04057521 Mercury (ng/L) 31 0 0.69 2.56 7.45 6 4 Sturgeon River at Nahma 04057521 Nitrate (mg/L as N) 31 0 0.006 0.062 0.36 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued[mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested]

Watershed 

number Site

USGS 

station 

number

Constituent

Number 

of 

samples 

collected

Number of 

censored 

results

Minimum 

concentration

Median 

concentration

Maximum 

concentration

Years 

of data 

used

S

4 Sturgeon River at Nahma 04057521 Nitrite (mg/L as N) 31 0 0.001 0.004 0.008 6 4 Sturgeon River at Nahma 04057521 pH 31 0 6.7 7.4 8 6 4 Sturgeon River at Nahma 04057521 Total phosphorus (mg/L as P) 31 0 0.009 0.019 0.044 6 4 Sturgeon River at Nahma 04057521 Specific conductance (μS/cm) 31 0 74 203 298 6 4 Sturgeon River at Nahma 04057521 Total Kjehldahl nitrogen 

(mg/L as N)

31 0 0.26 0.53 0.88 6 

4 Sturgeon River at Nahma 04057521 Total suspended solids (mg/L) 31 11 3 4 58 -- 4 Sturgeon River at Nahma 04057521 Turbidity (NTU) 31 0 1.9 4.4 16 6 4 Sturgeon River at Nahma 04057521 Water temperature (°C) 31 0 2.1 13.9 26 6 5 Manistique River above Manistique 04057004 Ammonia 

(mg/L as N)

44 0 0.008 0.017 0.048 7 

5 Manistique River above Manistique 04057004 Chloride (mg/L) 44 0 2 2 3 7 5 Manistique River above Manistique 04057004 Chromium (μg/L) 44 0 0.095 0.3845 0.79 7 5 Manistique River above Manistique 04057004 Copper (μg/L) 44 0 0.056 0.371 0.59 7 5 Manistique River above Manistique 04057004 Dissolved oxygen (mg/L) 44 0 7.2 9.025 12 7 5 Manistique River above Manistique 04057004 Lead (μg/L) 44 0 0.064 0.1655 0.407 7 5 Manistique River above Manistique 04057004 Mercury (ng/L) 44 0 0.78 2.4205 6.068 7 5 Manistique River above Manistique 04057004 Nitrate (mg/L as N) 44 0 0.027 0.0535 0.3 7 5 Manistique River above Manistique 04057004 Nitrite (mg/L as N) 44 1 0.002 0.003 0.007 7 5 Manistique River above Manistique 04057004 pH 44 0 6.69 7.5 8.1 7 5 Manistique River above Manistique 04057004 Total phosphorus (mg/L as P) 44 0 0.01 0.018 0.043 7 5 Manistique River above Manistique 04057004 Specific conductance (μS/cm) 44 0 66 179 222 7 5 Manistique River above Manistique 04057004 Total Kjehldahl nitrogen 

(mg/L as N)

44 0 0.28 0.45 0.7 7 

5 Manistique River above Manistique 04057004 Total suspended solids (mg/L) 44 16 3 5 41 -- 5 Manistique River above Manistique 04057004 Turbidity (NTU) 31 0 2.8 5.1 12 -- 5 Manistique River above Manistique 04057004 Water temperature (°C) 44 0 2 15.25 23.7 7 6 Tahquamenon River at Emerson 04045510 Ammonia (mg/L as N) 44 0 0.005 0.015 0.044 7 6 Tahquamenon River at Emerson 04045510 Chloride (mg/L) 44 0 2 2 4 7 6 Tahquamenon River at Emerson 04045510 Chromium (μg/L) 43 0 0.077 0.38 0.653 7 6 Tahquamenon River at Emerson 04045510 Copper (μg/L) 44 0 0.17 0.3875 0.95 7 6 Tahquamenon River at Emerson 04045510 Dissolved oxygen (mg/L) 43 0 6.8 8.9 14.5 7 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued [mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested] Watershed number Site USGS station number Constituent Number of samples collected Number of censored results Minimum concen- tration Median concen- tration Maximum concen- tration Years of data used S

6 Tahquamenon River at Emerson 04045510 Lead (μg/L) 44 0 0.031 0.1685 0.543 7 6 Tahquamenon River at Emerson 04045510 Mercury (ng/L) 44 0 0.63 3.09 9.632 7 6 Tahquamenon River at Emerson 04045510 Nitrate (mg/L as N) 44 0 0.015 0.0735 0.106 7 6 Tahquamenon River at Emerson 04045510 Nitrite (mg/L as N) 44 1 0.001 0.004 0.011 7 6 Tahquamenon River at Emerson 04045510 pH 42 0 6.51 7.43 8.1 7 6 Tahquamenon River at Emerson 04045510 Total phosphorus (mg/L as P) 44 0 0.011 0.022 0.042 7 6 Tahquamenon River at Emerson 04045510 Specific conductance (μS/cm) 44 0 44 149.5 215 7 6 Tahquamenon River at Emerson 04045510 Total Kjehldahl nitrogen (mg/L as N) 44 0 0.28 0.54 1.02 7 6 Tahquamenon River at Emerson 04045510 Total suspended solids (mg/L) 44 22 2 4 29 -- 6 Tahquamenon River at Emerson 04045510 Turbidity (NTU) 31 0 2 3.2 13 6 6 Tahquamenon River at Emerson 04045510 Water temperature (°C) 44 0 1 16.6 23.4 7 7 Pine River near Charles 04127925 Ammonia (mg/L as N) 31 1 0.009 0.017 0.11 6 7 Pine River near Charles 04127925 Chloride (mg/L) 31 0 1 3 6 6 7 Pine River near Charles 04127925 Chromium (μg/L) 31 0 0.709 1.29 8.08 6 7 Pine River near Charles 04127925 Copper (μg/L) 31 0 0.649 1.21 6.12 6 7 Pine River near Charles 04127925 Dissolved oxygen (mg/L) 31 0 6.9 9.4 12.9 6 7 Pine River near Charles 04127925 Lead (μg/L) 31 0 0.309 0.545 4.17 6 7 Pine River near Charles 04127925 Mercury (ng/L) 31 0 0.2 2.29 17.76 6 7 Pine River near Charles 04127925 Nitrate (mg/L as N) 30 9 0.008 0.021 0.16 -- 7 Pine River near Charles 04127925 Nitrite (mg/L as N) 31 13 0.002 0.01 0.031 -- 7 Pine River near Charles 04127925 pH 30 0 7.3 7.8 8.5 6 7 Pine River near Charles 04127925 Total phosphorus (mg/L as P) 31 0 0.036 0.067 0.39 6 7 Pine River near Charles 04127925 Specific conductance (μS/cm) 31 0 90 189 245 6 7 Pine River near Charles 04127925 Total Kjehldahl nitrogen (mg/L as N) 31 0 0.3 0.42 1.11 6 7 Pine River near Charles 04127925 Total suspended solids (mg/L) 31 0 11 24 460 6 7 Pine River near Charles 04127925 Turbidity (NTU) 31 0 13 31 350 6 7 Pine River near Charles 04127925 Water temperature (°C) 31 0 1 15 26.1 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued[mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested]

Watershed 

number Site

USGS 

station 

number

Constituent

Number 

of 

samples 

collected

Number of 

censored 

results

Minimum 

concentration

Median 

concentration

Maximum 

concentration

Years 

of data 

used

S

8 Cheboygan River at Cheboygan 04132052 Ammonia 

(mg/L as N)

34 1 0.01 0.0165 0.035 6 

8 Cheboygan River at Cheboygan 04132052 Chloride (mg/L) 34 0 6 8 16 6 8 Cheboygan River at Cheboygan 04132052 Chromium (μg/L) 33 16 0.033 0.081 0.24 -- 8 Cheboygan River at Cheboygan 04132052 Copper (μg/L) 33 0 0.27 0.55 0.969 6 8 Cheboygan River at Cheboygan 04132052 Dissolved oxygen (mg/L) 32 0 7.2 9.05 13 6 8 Cheboygan River at Cheboygan 04132052 Lead (μg/L) 33 0 0.0178 0.0413 0.408 6 8 Cheboygan River at Cheboygan 04132052 Mercury (ng/L) 34 0 0.1 0.435 1.43 6 8 Cheboygan River at Cheboygan 04132052 Nitrate (mg/L as N) 32 6 0.01 0.031 0.143 -- 8 Cheboygan River at Cheboygan 04132052 Nitrite (mg/L as N) 33 21 0.002 0.01 0.01 -- 8 Cheboygan River at Cheboygan 04132052 pH 31 0 7.5 8.2 8.4 6 8 Cheboygan River at Cheboygan 04132052 Total phosphorus (mg/L as P) 34 7 0.005 0.01 0.04 -- 8 Cheboygan River at Cheboygan 04132052 Specific conductance (μS/cm) 33 0 288 314 336 6 8 Cheboygan River at Cheboygan 04132052 Total Kjehldahl nitrogen 

(mg/L as N)

34 0 0.21 0.28 0.37 6 

8 Cheboygan River at Cheboygan 04132052 Total suspended solids (mg/L) 33 22 1 4 7 -- 8 Cheboygan River at Cheboygan 04132052 Turbidity (NTU) 33 21 0.4 1 3.2 -- 8 Cheboygan River at Cheboygan 04132052 Water temperature (°C) 34 0 2.3 20.3 28.1 6 

10 Manistee River at Parkdale 04126010 Ammonia 

(mg/L as N)

31 0 0.007 0.019 0.032 6 

10 Manistee River at Parkdale 04126010 Chloride (mg/L) 31 0 8 11 33 6 10 Manistee River at Parkdale 04126010 Chromium (μg/L) 31 2 0.04 0.223 0.418 6 10 Manistee River at Parkdale 04126010 Copper (μg/L) 31 0 0.223 0.444 0.775 6 10 Manistee River at Parkdale 04126010 Dissolved oxygen (mg/L) 30 0 7.5 9.05 12.8 6 10 Manistee River at Parkdale 04126010 Lead (μg/L) 31 0 0.072 0.178 0.298 6 10 Manistee River at Parkdale 04126010 Mercury (ng/L) 31 0 0.28 1.06 3.39 6 10 Manistee River at Parkdale 04126010 Nitrate (mg/L as N) 31 0 0.099 0.148 0.28 6 10 Manistee River at Parkdale 04126010 Nitrite (mg/L as N) 31 0 0.002 0.005 0.008 6 10 Manistee River at Parkdale 04126010 pH 31 0 7.5 7.9 8.2 6 10 Manistee River at Parkdale 04126010 Total phosphorus (mg/L as P) 31 0 0.015 0.021 0.037 6 10 Manistee River at Parkdale 04126010 Specific conductance (μS/cm) 31 0 266 312 353 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued [mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested] Watershed number Site USGS station number Constituent Number of samples collected Number of censored results Minimum concen- tration Median concen- tration Maximum concen- tration Years of data used S

10 Manistee River at Parkdale 04126010 Total Kjehldahl nitrogen (mg/L as N) 31 0 0.16 0.25 0.8 6 10 Manistee River at Parkdale 04126010 Total suspended solids (mg/L) 31 2 4 10 16 6 10 Manistee River at Parkdale 04126010 Turbidity (NTU) 31 0 2.1 5.3 11 6 10 Manistee River at Parkdale 04126010 Water temperature (°C) 31 0 0.1 15.3 23.3 6 

11 Pere Marquette River at Scottville 04122500 Ammonia (mg/L as N) 47 0 0.009 0.02 0.046 7 11 Pere Marquette River at Scottville 04122500 Chloride (mg/L) 47 0 5 13 51 7 11 Pere Marquette River at Scottville 04122500 Chromium (μg/L) 47 0 0.01832 0.368 0.878 7 11 Pere Marquette River at Scottville 04122500 Copper (μg/L) 47 0 0.241 0.47 1.24 7 11 Pere Marquette River at Scottville 04122500 Dissolved oxygen (mg/L) 46 0 5.2 9.41 13.4 7 11 Pere Marquette River at Scottville 04122500 Lead (μg/L) 47 0 0.0514 0.271 0.683 7 11 Pere Marquette River at Scottville 04122500 Mercury (ng/L) 47 0 0.46 1.84 5.312 7 11 Pere Marquette River at Scottville 04122500 Nitrate (mg/L as N) 47 0 0.042 0.104 0.32 7 11 Pere Marquette River at Scottville 04122500 Nitrite (mg/L as N) 47 0 0.002 0.004 0.013 7 11 Pere Marquette River at Scottville 04122500 pH 47 0 7 7.85 8.18 7 11 Pere Marquette River at Scottville 04122500 Total phosphorus (mg/L as P) 47 0 0.017 0.033 0.069 7 11 Pere Marquette River at Scottville 04122500 Specific conductance (μS/cm) 46 0 220 340 387 7 11 Pere Marquette River at Scottville 04122500 Total Kjehldahl nitrogen (mg/L as N) 47 0 0.13 0.36 0.91 7 11 Pere Marquette River at Scottville 04122500 Total suspended solids (mg/L) 47 4 4 12 75 -- 11 Pere Marquette River at Scottville 04122500 Turbidity (NTU) 47 12 0 4.1 16 -- 11 Pere Marquette River at Scottville 04122500 Water temperature (°C) 47 0 1.7 15.4 21.9 7 

12 Muskegon River near Bridgeton 04122030 Ammonia (mg/L as N) 78 0 0.008 0.021 0.099 7 12 Muskegon River near Bridgeton 04122030 Chloride (mg/L) 78 0 12 18.5 26 7 12 Muskegon River near Bridgeton 04122030 Chromium (μg/L) 78 10 0 0.152 1.88 -- 12 Muskegon River near Bridgeton 04122030 Copper (μg/L) 78 0 0.338 0.627 1.98 7 12 Muskegon River near Bridgeton 04122030 Dissolved oxygen (mg/L) 75 0 6.42 9.4 13.4 7 12 Muskegon River near Bridgeton 04122030 Lead (μg/L) 78 0 0.0406 0.1465 2.18 7 12 Muskegon River near Bridgeton 04122030 Mercury (ng/L) 78 0 0.23 1.101 34.004 7 12 Muskegon River near Bridgeton 04122030 Nitrate (mg/L as N) 78 0 0.042 0.3 0.68 7 12 Muskegon River near Bridgeton 04122030 Nitrite (mg/L as N) 78 0 0.003 0.007 0.021 7 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued[mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested]

Watershed 

number Site

USGS 

station 

number

Constituent

Number 

of 

samples 

collected

Number of 

censored 

results

Minimum 

concentration

Median 

concentration

Maximum 

concentration

Years 

of data 

used

S

12 Muskegon River near Bridgeton 04122030 pH 77 0 7.12 7.9 9 7 12 Muskegon River near Bridgeton 04122030 Total phosphorus (mg/L as P) 78 0 0.006 0.026 0.186 7 12 Muskegon River near Bridgeton 04122030 Specific conductance (μS/cm) 76 0 260 360.5 425 7 12 Muskegon River near Bridgeton 04122030 Total Kjehldahl nitrogen 

(mg/L as N)

78 0 0.24 0.4 0.93 7 

12 Muskegon River near Bridgeton 04122030 Total suspended solids (mg/L) 78 4 0 10 97 -- 12 Muskegon River near Bridgeton 04122030 Turbidity (NTU) 68 12 0 2.6 58 -- 12 Muskegon River near Bridgeton 04122030 Water temperature (°C) 77 0 0.8 14.7 25.1 7 13 Muskegon River near Hersey 04121621 Ammonia 

(mg/L as N)

32 0 0.007 0.0165 0.089 6 

13 Muskegon River near Hersey 04121621 Chloride (mg/L) 32 0 2 15.5 72 6 13 Muskegon River near Hersey 04121621 Chromium (μg/L) 32 3 0.036 0.232 1.75 -- 13 Muskegon River near Hersey 04121621 Copper (μg/L) 32 0 0.34 0.5685 2.23 6 13 Muskegon River near Hersey 04121621 Dissolved oxygen (mg/L) 31 0 7.7 9.3 13.1 6 13 Muskegon River near Hersey 04121621 Lead (μg/L) 32 0 0.053 0.202 2.55 6 13 Muskegon River near Hersey 04121621 Mercury (ng/L) 32 0 0.57 1.54 13.71 6 13 Muskegon River near Hersey 04121621 Nitrate (mg/L as N) 32 0 0.095 0.1895 0.31 6 13 Muskegon River near Hersey 04121621 Nitrite (mg/L as N) 32 0 0.003 0.005 0.012 6 13 Muskegon River near Hersey 04121621 pH 32 0 7.3 7.8 8.29 6 13 Muskegon River near Hersey 04121621 Total phosphorus (mg/L as P) 32 0 0.013 0.031 0.183 6 13 Muskegon River near Hersey 04121621 Specific conductance (μS/cm) 32 0 183 311 403 6 13 Muskegon River near Hersey 04121621 Total Kjehldahl nitrogen 

(mg/L as N)

32 0 0.22 0.44 1.18 6 

13 Muskegon River near Hersey 04121621 Total suspended solids (mg/L) 32 3 4 10.5 100 -- 13 Muskegon River near Hersey 04121621 Turbidity (NTU) 32 0 1.3 4.45 49 6 13 Muskegon River near Hersey 04121621 Water temperature (°C) 32 0 1.2 15.65 21.4 6 14 Grand River near Eastmanville 04119400 Ammonia 

(mg/L as N)

79 0 0.011 0.095 0.81 7 

14 Grand River near Eastmanville 04119400 Chloride (mg/L) 79 0 24 54 77 7 14 Grand River near Eastmanville 04119400 Chromium (μg/L) 78 0 0.147 0.895 4.73 7 14 Grand River near Eastmanville 04119400 Copper (μg/L) 79 0 1.18 2.35 393 7 14 Grand River near Eastmanville 04119400 Dissolved oxygen (mg/L) 78 0 6.3 10.3 16.9 7 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued [mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested] Watershed number Site USGS station number Constituent Number of samples collected Number of censored results Minimum concen- tration Median concen- tration Maximum concen- tration Years of data used S

14 Grand River near Eastmanville 04119400 Lead (μg/L) 79 0 0.293 1.12 5.38 7 14 Grand River near Eastmanville 04119400 Mercury (ng/L) 79 0 0.66 3.36 21.813 7 14 Grand River near Eastmanville 04119400 Nitrate (mg/L as N) 79 0 0.26 1.53 5.16 7 14 Grand River near Eastmanville 04119400 Nitrite (mg/L as N) 79 0 0.016 0.032 0.102 7 14 Grand River near Eastmanville 04119400 pH 79 0 7.2 8 8.9 7 14 Grand River near Eastmanville 04119400 Total phosphorus (mg/L as P) 79 0 0.033 0.109 0.31 7 14 Grand River near Eastmanville 04119400 Specific conductance (μS/cm) 79 0 388 618 800 7 14 Grand River near Eastmanville 04119400 Total Kjehldahl nitrogen (mg/L as N) 79 0 0.64 1.14 2.7 7 14 Grand River near Eastmanville 04119400 Total suspended solids (mg/L) 79 2 4 28 150 7 14 Grand River near Eastmanville 04119400 Turbidity (NTU) 66 0 2.2 14 140 6 14 Grand River near Eastmanville 04119400 Water temperature (°C) 79 0 0.2 16.2 28.2 7 15 Grand River at Ionia 04116000 Ammonia (mg/L as N) 31 2 0.006 0.017 0.28 6 15 Grand River at Ionia 04116000 Chloride (mg/L) 31 0 27 53 94 6 15 Grand River at Ionia 04116000 Chromium (μg/L) 31 0 0.112 0.526 15.1 6 15 Grand River at Ionia 04116000 Copper (μg/L) 31 0 1.44 2.53 12.4 6 15 Grand River at Ionia 04116000 Dissolved oxygen (mg/L) 31 0 5.4 8.87 14.5 6 15 Grand River at Ionia 04116000 Lead (μg/L) 31 0 0.261 0.851 18 6 15 Grand River at Ionia 04116000 Mercury (ng/L) 31 0 0.58 2.56 52.23 6 15 Grand River at Ionia 04116000 Nitrate (mg/L as N) 31 0 0.055 1.82 5.4 6 15 Grand River at Ionia 04116000 Nitrite (mg/L as N) 31 0 0.008 0.02 0.056 6 15 Grand River at Ionia 04116000 pH 33 0 7 8 8.7 6 15 Grand River at Ionia 04116000 Total phosphorus (mg/L as P) 31 0 0.048 0.112 0.29 6 15 Grand River at Ionia 04116000 Specific conductance (μS/cm) 33 0 420 664 739 6 15 Grand River at Ionia 04116000 Total Kjehldahl nitrogen (mg/L as N) 31 0 0.55 1 1.52 6 15 Grand River at Ionia 04116000 Total suspended solids (mg/L) 31 1 4 18 830 6 15 Grand River at Ionia 04116000 Turbidity (NTU) 31 0 2.1 12 620 6 15 Grand River at Ionia 04116000 Water temperature (°C) 33 0 0.1 15.4 27.23 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued[mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested]

Watershed 

number Site

USGS 

station 

number

Constituent

Number 

of 

samples 

collected

Number of 

censored 

results

Minimum 

concentration

Median 

concentration

Maximum 

concentration

Years 

of data 

used

S

16 Kalamazoo River at New Richmond 04108660 Ammonia 

(mg/L as N)

79 0 0.004 0.048 0.3 5 

16 Kalamazoo River at New Richmond 04108660 Chloride (mg/L) 79 0 23 44 62 5 16 Kalamazoo River at New Richmond 04108660 Chromium (μg/L) 79 0 0.05 0.608 1.912 5 16 Kalamazoo River at New Richmond 04108660 Copper (μg/L) 79 0 0.806 1.48 2.74 5 16 Kalamazoo River at New Richmond 04108660 Dissolved oxygen (mg/L) 78 0 5.9 8.85 13.7 5 16 Kalamazoo River at New Richmond 04108660 Lead (μg/L) 79 0 0.387 1.334 2.51 5 16 Kalamazoo River at New Richmond 04108660 Mercury (ng/L) 78 0 1.09 5.59 14.2 5 16 Kalamazoo River at New Richmond 04108660 Nitrate (mg/L as N) 79 0 0.31 1.09 2.86 5 16 Kalamazoo River at New Richmond 04108660 Nitrite (mg/L as N) 79 0 0.009 0.019 0.076 5 16 Kalamazoo River at New Richmond 04108660 pH 79 0 7.2 7.9 8.8 5 16 Kalamazoo River at New Richmond 04108660 Total phosphorus (mg/L as P) 79 0 0.024 0.085 0.192 5 16 Kalamazoo River at New Richmond 04108660 Specific conductance (μS/cm) 79 0 389 575 698 5 16 Kalamazoo River at New Richmond 04108660 Total Kjehldahl nitrogen 

(mg/L as N)

79 0 0.47 0.89 1.36 5 

16 Kalamazoo River at New Richmond 04108660 Total suspended solids (mg/L) 79 3 2 20 50 5 16 Kalamazoo River at New Richmond 04108660 Turbidity (NTU) 66 0 2.2 11.5 36 5 16 Kalamazoo River at New Richmond 04108660 Water temperature (°C) 79 0 0.1 16.3 26.7 5 17 Kalamazoo River near Augusta 04105707 Ammonia 

(mg/L as N)

31 0 0.013 0.05 0.15 6 

17 Kalamazoo River near Augusta 04105707 Chloride (mg/L) 31 0 13 41 56 6 17 Kalamazoo River near Augusta 04105707 Chromium (μg/L) 31 0 0.105 0.887 2.83 6 17 Kalamazoo River near Augusta 04105707 Copper (μg/L) 31 0 0.657 1.45 3.49 6 17 Kalamazoo River near Augusta 04105707 Dissolved oxygen (mg/L) 29 0 6.2 7.5 12.4 6 17 Kalamazoo River near Augusta 04105707 Lead (μg/L) 31 0 0.269 1.02 6.29 6 17 Kalamazoo River near Augusta 04105707 Mercury (ng/L) 31 0 1.01 3.73 13.21 6 17 Kalamazoo River near Augusta 04105707 Nitrate (mg/L as N) 31 0 0.65 0.97 2.38 6 17 Kalamazoo River near Augusta 04105707 Nitrite (mg/L as N) 31 0 0.006 0.013 0.063 6 17 Kalamazoo River near Augusta 04105707 pH 30 0 7.1 7.8 9.1 6 17 Kalamazoo River near Augusta 04105707 Total phosphorus (mg/L as P) 31 0 0.033 0.072 0.155 6 17 Kalamazoo River near Augusta 04105707 Specific conductance (μS/cm) 30 0 330 618.5 689 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued [mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested] Watershed number Site USGS station number Constituent Number of samples collected Number of censored results Minimum concen- tration Median concen- tration Maximum concen- tration Years of data used S

17 Kalamazoo River near Augusta 04105707 Total Kjehldahl nitrogen (mg/L as N) 31 0 0.37 0.67 1.12 6 17 Kalamazoo River near Augusta 04105707 Total suspended solids (mg/L) 31 3 4 11 39 -- 17 Kalamazoo River near Augusta 04105707 Turbidity (NTU) 31 0 1.5 6.4 18 6 17 Kalamazoo River near Augusta 04105707 Water temperature (°C) 30 1 0 17.25 25.6 6 18 St. Joseph River at St. Joseph 04102080 Ammonia (mg/L as N) 51 2 0 0.017 0.31 7 18 St. Joseph River at St. Joseph 04102080 Chloride (mg/L) 51 0 18 30 45 7 18 St. Joseph River at St. Joseph 04102080 Chromium (μg/L) 51 1 0 0.46 3.87 7 18 St. Joseph River at St. Joseph 04102080 Copper (μg/L) 51 0 0.865 1.48 4.92 7 18 St. Joseph River at St. Joseph 04102080 Dissolved oxygen (mg/L) 45 0 6.6 9.4 14.9 7 18 St. Joseph River at St. Joseph 04102080 Lead (μg/L) 51 0 0.338 0.854 5.2 7 18 St. Joseph River at St. Joseph 04102080 Mercury (ng/L) 51 0 0.96 3.18 15.98 7 18 St. Joseph River at St. Joseph 04102080 Nitrate (mg/L as N) 51 0 0.77 1.52 4.3 7 18 St. Joseph River at St. Joseph 04102080 Nitrite (mg/L as N) 51 0 0.005 0.013 0.039 7 18 St. Joseph River at St. Joseph 04102080 pH 49 0 6.8 7.9 9.2 7 18 St. Joseph River at St. Joseph 04102080 Total phosphorus (mg/L as P) 51 0 0.034 0.07 0.4 7 18 St. Joseph River at St. Joseph 04102080 Specific conductance (μS/cm) 47 0 356 556 631 7 18 St. Joseph River at St. Joseph 04102080 Total Kjehldahl nitrogen (mg/L as N) 51 0 0.31 0.67 1.67 7 18 St. Joseph River at St. Joseph 04102080 Total suspended solids (mg/L) 51 1 4 18 97 7 18 St. Joseph River at St. Joseph 04102080 Turbidity (NTU) 41 2 0 7.4 120 6 18 St. Joseph River at St. Joseph 04102080 Water temperature (°C) 49 0 1 17.5 28.8 7 19 St. Joseph River at Mottville 04099000 Ammonia (mg/L as N) 26 0 0.016 0.058 0.13 6 19 St. Joseph River at Mottville 04099000 Chloride (mg/L) 26 0 15 22 34 6 19 St. Joseph River at Mottville 04099000 Chromium (μg/L) 26 2 0.005 0.0905 0.47 6 19 St. Joseph River at Mottville 04099000 Copper (μg/L) 26 0 0.322 0.6265 1.24 6 19 St. Joseph River at Mottville 04099000 Dissolved oxygen (mg/L) 24 0 5.9 7.75 13.3 6 19 St. Joseph River at Mottville 04099000 Lead (μg/L) 26 0 0.085 0.273 0.89 6 19 St. Joseph River at Mottville 04099000 Mercury (ng/L) 26 0 0.56 1.22 7.89 6 19 St. Joseph River at Mottville 04099000 Nitrate (mg/L as N) 26 0 0.87 1.43 2.4 6 19 St. Joseph River at Mottville 04099000 Nitrite (mg/L as N) 26 0 0.009 0.0155 0.032 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued[mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested]

Watershed 

number Site

USGS 

station 

number

Constituent

Number 

of 

samples 

collected

Number of 

censored 

results

Minimum 

concentration

Median 

concentration

Maximum 

concentration

Years 

of data 

used

S

19 St. Joseph River at Mottville 04099000 pH 26 0 7.5 7.9 8.2 6 19 St. Joseph River at Mottville 04099000 Total phosphorus (mg/L as P) 26 0 0.012 0.0315 0.093 6 19 St. Joseph River at Mottville 04099000 Specific conductance (μS/cm) 26 0 350 499 551 6 19 St. Joseph River at Mottville 04099000 Total Kjehldahl nitrogen 

(mg/L as N)

26 0 0.41 0.525 0.93 6 

19 St. Joseph River at Mottville 04099000 Total suspended solids (mg/L) 26 7 4 6 20 -- 19 St. Joseph River at Mottville 04099000 Turbidity (NTU) 26 0 0.7 3.45 16 6 19 St. Joseph River at Mottville 04099000 Water temperature (°C) 27 0 0.02 18.9 27.3 6 20 River Raisin at Monroe 04176540 Ammonia 

(mg/L as N)

31 7 0.01 0.042 0.17 -- 

20 River Raisin at Monroe 04176540 Chloride (mg/L) 31 0 24 46 64 6 20 River Raisin at Monroe 04176540 Chromium (μg/L) 31 0 0.096 0.601 4.23 6 20 River Raisin at Monroe 04176540 Copper (μg/L) 31 0 1.6 2.79 5.55 6 20 River Raisin at Monroe 04176540 Dissolved oxygen (mg/L) 31 0 6.1 9.5 12.9 6 20 River Raisin at Monroe 04176540 Lead (μg/L) 31 0 0.275 0.664 4.19 6 20 River Raisin at Monroe 04176540 Mercury (ng/L) 31 0 1.14 2.07 12.04 6 20 River Raisin at Monroe 04176540 Nitrate (mg/L as N) 31 0 0.032 1.38 10.9 6 20 River Raisin at Monroe 04176540 Nitrite (mg/L as N) 31 1 0.008 0.017 0.086 6 20 River Raisin at Monroe 04176540 pH 32 0 7.2 7.935 8.6 6 20 River Raisin at Monroe 04176540 Total phosphorus (mg/L as P) 31 0 0.033 0.078 0.3 6 20 River Raisin at Monroe 04176540 Specific conductance (μS/cm) 31 0 367 604 759 6 20 River Raisin at Monroe 04176540 Total Kjehldahl nitrogen 

(mg/L as N)

31 0 0.4 0.84 1.43 6 

20 River Raisin at Monroe 04176540 Total suspended solids (mg/L) 31 0 5 13 110 6 20 River Raisin at Monroe 04176540 Turbidity (NTU) 31 0 3.9 11 150 6 20 River Raisin at Monroe 04176540 Water temperature (°C) 32 0 0.3 20.85 28.4 6 21 Huron River at Rockwood 04175120 Ammonia 

(mg/L as N)

31 0 0.015 0.064 0.186 6 

21 Huron River at Rockwood 04175120 Chloride (mg/L) 31 0 69 103 174 6 21 Huron River at Rockwood 04175120 Chromium (μg/L) 31 0 0.094 0.415 1.34 6 21 Huron River at Rockwood 04175120 Copper (μg/L) 31 0 1.03 1.59 3.63 6 21 Huron River at Rockwood 04175120 Dissolved oxygen (mg/L) 31 0 4.4 8 14.8 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued [mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested] Watershed number Site USGS station number Constituent Number of samples collected Number of censored results Minimum concen- tration Median concen- tration Maximum concen- tration Years of data used S

21 Huron River at Rockwood 04175120 Lead (μg/L) 31 0 0.475 1.46 2.84 6 21 Huron River at Rockwood 04175120 Mercury (ng/L) 31 0 0.4 1.24 4.1 6 21 Huron River at Rockwood 04175120 Nitrate (mg/L as N) 31 0 0.026 0.47 1.48 6 21 Huron River at Rockwood 04175120 Nitrite (mg/L as N) 31 0 0.005 0.011 0.037 6 21 Huron River at Rockwood 04175120 pH 31 0 7 7.8 8.3 6 21 Huron River at Rockwood 04175120 Total phosphorus (mg/L as P) 31 0 0.018 0.047 0.09 6 21 Huron River at Rockwood 04175120 Specific conductance (μS/cm) 31 0 257 905 1080 6 21 Huron River at Rockwood 04175120 Total Kjehldahl nitrogen (mg/L as N) 31 0 0.54 0.7 1.02 6 21 Huron River at Rockwood 04175120 Total suspended solids (mg/L) 31 0 4 13 175 6 21 Huron River at Rockwood 04175120 Turbidity (NTU) 31 0 3.3 8.8 37 6 21 Huron River at Rockwood 04175120 Water temperature (°C) 31 0 1.1 17.7 25.5 6 22 River Rouge at River Rouge 04168550 Ammonia (mg/L as N) 47 0 0.02 0.136 0.82 6 22 River Rouge at River Rouge 04168550 Chloride (mg/L) 47 0 23 68 256 6 22 River Rouge at River Rouge 04168550 Chromium (μg/L) 47 0 0.126 2.021 10.118 6 22 River Rouge at River Rouge 04168550 Copper (μg/L) 47 0 0.793 3.2 12.698 6 22 River Rouge at River Rouge 04168550 Dissolved oxygen (mg/L) 41 0 2.4 6 13.9 6 22 River Rouge at River Rouge 04168550 Lead (μg/L) 47 0 0.112 2.249 12.356 6 22 River Rouge at River Rouge 04168550 Mercury (ng/L) 47 0 0.4 4.667 29.584 6 22 River Rouge at River Rouge 04168550 Nitrate (mg/L as N) 47 0 0.29 0.66 1.46 6 22 River Rouge at River Rouge 04168550 Nitrite (mg/L as N) 47 0 0.003 0.023 0.057 6 22 River Rouge at River Rouge 04168550 pH 46 0 6.7 7.6 8.5 6 22 River Rouge at River Rouge 04168550 Total phosphorus (mg/L as P) 47 0 0.009 0.079 0.42 6 22 River Rouge at River Rouge 04168550 Specific conductance (μS/cm) 41 0 238 488 1190 6 22 River Rouge at River Rouge 04168550 Total Kjehldahl nitrogen (mg/L as N) 47 0 0.17 0.62 2 6 22 River Rouge at River Rouge 04168550 Total suspended solids (mg/L) 47 0 1 17 130 6 22 River Rouge at River Rouge 04168550 Turbidity (NTU) 34 1 1 15 52 6 22 River Rouge at River Rouge 04168550 Water temperature (°C) 47 0 0.2 23.4 29 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued[mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested]

Watershed 

number Site

USGS 

station 

number

Constituent

Number 

of 

samples 

collected

Number of 

censored 

results

Minimum 

concentration

Median 

concentration

Maximum 

concentration

Years 

of data 

used

S

23 Clinton River at Mt. Clemens 04165553 Ammonia 

(mg/L as N)

79 1 0.016 0.1 0.76 6 

23 Clinton River at Mt. Clemens 04165553 Chloride (mg/L) 79 0 25 137 447 6 23 Clinton River at Mt. Clemens 04165553 Chromium (μg/L) 78 0 0.45 2.12 32.739 6 23 Clinton River at Mt. Clemens 04165553 Copper (μg/L) 78 0 1.82 3.92 40.575 6 23 Clinton River at Mt. Clemens 04165553 Dissolved oxygen (mg/L) 76 0 2.9 7.55 14.2 6 23 Clinton River at Mt. Clemens 04165553 Lead (μg/L) 78 0 0.519 1.995 50.766 6 23 Clinton River at Mt. Clemens 04165553 Mercury (ng/L) 78 1 0.1 4 106.875 6 23 Clinton River at Mt. Clemens 04165553 Nitrate (mg/L as N) 79 0 0.7 1.57 3.9 6 23 Clinton River at Mt. Clemens 04165553 Nitrite (mg/L as N) 79 0 0.012 0.039 0.106 6 23 Clinton River at Mt. Clemens 04165553 pH 78 0 6.9 7.7 8.3 6 23 Clinton River at Mt. Clemens 04165553 Total phosphorus (mg/L as P) 79 0 0.05 0.174 0.87 6 23 Clinton River at Mt. Clemens 04165553 Specific conductance (μS/cm) 75 0 210 844 1460 6 23 Clinton River at Mt. Clemens 04165553 Total Kjehldahl nitrogen 

(mg/L as N)

79 0 0.65 1.03 3.1 6 

23 Clinton River at Mt. Clemens 04165553 Total suspended solids (mg/L) 79 1 4 21 470 6 23 Clinton River at Mt. Clemens 04165553 Turbidity (NTU) 66 0 2.7 19.5 310 6 23 Clinton River at Mt. Clemens 04165553 Water temperature (°C) 78 0 0.6 15.6 25.7 6 24 Black River at Port Huron 04160075 Ammonia 

(mg/L as N)

23 2 0.01 0.036 0.17 -- 

24 Black River at Port Huron 04160075 Chloride (mg/L) 23 0 12 28 70 6 24 Black River at Port Huron 04160075 Chromium (μg/L) 23 0 0.146 0.511 1.25 6 24 Black River at Port Huron 04160075 Copper (μg/L) 23 0 1.13 2.13 4.08 6 24 Black River at Port Huron 04160075 Dissolved oxygen (mg/L) 20 0 6.76 7.7 13.1 6 24 Black River at Port Huron 04160075 Lead (μg/L) 23 0 0.218 0.559 1.66 6 24 Black River at Port Huron 04160075 Mercury (ng/L) 23 0 0.28 1.21 6.52 6 24 Black River at Port Huron 04160075 Nitrate (mg/L as N) 23 0 0.026 1.03 7.46 6 24 Black River at Port Huron 04160075 Nitrite (mg/L as N) 23 0 0.003 0.009 0.116 6 24 Black River at Port Huron 04160075 pH 21 0 7.4 8 8.3 6 24 Black River at Port Huron 04160075 Total phosphorus (mg/L as P) 23 0 0.015 0.037 0.14 6 24 Black River at Port Huron 04160075 Specific conductance (μS/cm) 21 0 251 421 740 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued [mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested] Watershed number Site USGS station number Constituent Number of samples collected Number of censored results Minimum concen- tration Median concen- tration Maximum concen- tration Years of data used S

24 Black River at Port Huron 04160075 Total Kjehldahl nitrogen (mg/L as N) 23 0 0.2 0.59 1.27 6 24 Black River at Port Huron 04160075 Total suspended solids (mg/L) 23 1 4 13 38 6 24 Black River at Port Huron 04160075 Turbidity (NTU) 23 0 4.1 12 46 6 24 Black River at Port Huron 04160075 Water temperature (°C) 21 0 1.6 15.9 25.9 6 25 Flint River near Fosters 04149000 Ammonia (mg/L as N) 31 4 0.01 0.05 0.93 -- 25 Flint River near Fosters 04149000 Chloride (mg/L) 31 0 54 90 232 6 25 Flint River near Fosters 04149000 Chromium (μg/L) 31 0 0.438 1.24 7.58 6 25 Flint River near Fosters 04149000 Copper (μg/L) 31 0 1.77 2.93 13.5 6 25 Flint River near Fosters 04149000 Dissolved oxygen (mg/L) 30 0 7 8.56 13.2 6 25 Flint River near Fosters 04149000 Lead (μg/L) 31 0 0.568 1.81 16.9 6 25 Flint River near Fosters 04149000 Mercury (ng/L) 31 0 0.76 3.69 29.71 6 25 Flint River near Fosters 04149000 Nitrate (mg/L as N) 31 0 0.62 2.3 5.8 6 25 Flint River near Fosters 04149000 Nitrite (mg/L as N) 31 0 0.009 0.024 0.061 6 25 Flint River near Fosters 04149000 pH 31 0 7.5 8 8.7 6 25 Flint River near Fosters 04149000 Total phosphorus (mg/L as P) 31 0 0.055 0.152 0.73 6 25 Flint River near Fosters 04149000 Specific conductance (μS/cm) 31 0 511 724 957 6 25 Flint River near Fosters 04149000 Total Kjehldahl nitrogen (mg/L as N) 31 0 0.73 1.1 4.5 6 25 Flint River near Fosters 04149000 Total suspended solids (mg/L) 31 2 4 29 290 6 25 Flint River near Fosters 04149000 Turbidity (NTU) 31 0 4.6 18 180 6 25 Flint River near Fosters 04149000 Water temperature (°C) 31 0 0.1 18.1 26.1 6 26 Cass River near Bridgeport 04152002 Ammonia (mg/L as N) 31 5 0.01 0.025 0.5 -- 26 Cass River near Bridgeport 04152002 Chloride (mg/L) 31 0 20 46 88 6 26 Cass River near Bridgeport 04152002 Chromium (μg/L) 31 0 0.187 0.82 2.07 6 26 Cass River near Bridgeport 04152002 Copper (μg/L) 31 0 1.15 2.06 2.94 6 26 Cass River near Bridgeport 04152002 Dissolved oxygen (mg/L) 29 0 5.6 8.6 12 6 26 Cass River near Bridgeport 04152002 Lead (μg/L) 31 0 0.435 0.689 2.39 6 26 Cass River near Bridgeport 04152002 Mercury (ng/L) 31 0 1.06 2.06 5.74 6 26 Cass River near Bridgeport 04152002 Nitrate (mg/L as N) 31 0 0.161 1.86 7.1 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued[mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested]

Watershed 

number Site

USGS 

station 

number

Constituent

Number 

of 

samples 

collected

Number of 

censored 

results

Minimum 

concentration

Median 

concentration

Maximum 

concentration

Years 

of data 

used

S

26 Cass River near Bridgeport 04152002 Nitrite (mg/L as N) 31 0 0.005 0.02 0.047 6 26 Cass River near Bridgeport 04152002 pH 30 0 7.23 7.95 8.4 6 26 Cass River near Bridgeport 04152002 Total phosphorus (mg/L as P) 31 0 0.042 0.08 0.2 6 26 Cass River near Bridgeport 04152002 Specific conductance (μS/cm) 31 0 403 682 800 6 26 Cass River near Bridgeport 04152002 Total Kjehldahl nitrogen 

(mg/L as N)

31 0 0.51 0.95 1.16 6 

26 Cass River near Bridgeport 04152002 Total suspended solids (mg/L) 31 0 7 28 63 6 26 Cass River near Bridgeport 04152002 Turbidity (NTU) 31 0 10 24 62 6 26 Cass River near Bridgeport 04152002 Water temperature (°C) 31 1 0 15.1 27 6 27 Shiawassee River near Fergus 04145000 Ammonia 

(mg/L as N)

34 1 0.007 0.0305 0.25 6 

27 Shiawassee River near Fergus 04145000 Chloride (mg/L) 34 0 33 69 117 6 27 Shiawassee River near Fergus 04145000 Chromium (μg/L) 34 0 0.132 0.534 2.7 6 27 Shiawassee River near Fergus 04145000 Copper (μg/L) 34 0 1.15 1.765 3.48 6 27 Shiawassee River near Fergus 04145000 Dissolved oxygen (mg/L) 34 0 6 8.5 13.6 6 27 Shiawassee River near Fergus 04145000 Lead (μg/L) 34 0 0.191 0.674 2.38 6 27 Shiawassee River near Fergus 04145000 Mercury (ng/L) 34 0 0.59 1.875 5.33 6 27 Shiawassee River near Fergus 04145000 Nitrate (mg/L as N) 34 0 0.181 0.695 2.5 6 27 Shiawassee River near Fergus 04145000 Nitrite (mg/L as N) 34 0 0.004 0.01 0.048 6 27 Shiawassee River near Fergus 04145000 pH 34 0 7.6 8.015 8.5 6 27 Shiawassee River near Fergus 04145000 Total phosphorus (mg/L as P) 34 0 0.024 0.063 0.177 6 27 Shiawassee River near Fergus 04145000 Specific conductance (μS/cm) 34 0 463 674 816 6 27 Shiawassee River near Fergus 04145000 Total Kjehldahl nitrogen 

(mg/L as N)

34 0 0.52 0.685 1.35 6 

27 Shiawassee River near Fergus 04145000 Total suspended solids (mg/L) 34 4 4 17.5 72 -- 27 Shiawassee River near Fergus 04145000 Turbidity (NTU) 34 0 1.6 10 38 6 27 Shiawassee River near Fergus 04145000 Water temperature (°C) 34 0 0.2 18.2 26.9 6 28 Tittabawassee River near Saginaw 04156510 Ammonia 

(mg/L as N)

31 0 0.023 0.071 0.28 6 

28 Tittabawassee River near Saginaw 04156510 Chloride (mg/L) 31 0 30 85 204 6 28 Tittabawassee River near Saginaw 04156510 Chromium (μg/L) 31 0 0.057 0.47 2.25 6 28 Tittabawassee River near Saginaw 04156510 Copper (μg/L) 31 0 1.24 1.69 2.75 6 
Appendix 1. Summary of data collected at select Michigan Water-Chemistry Monitoring Progam stream sites, 1999–2005.—Continued [mg/L, milligrams per liter; μg/L, micrograms per liter, ng/L, nanograms per liter, μS/cm, microsiemens per centimeter; °C, degrees Celsius; USGS, U.S. Geological Survey; N, NitNephelometric Turbidity Unit; -- , trend not tested] Watershed number Site USGS station number Constituent Number of samples collected Number of censored results Minimum concen- tration Median concen- tration Maximum concen- tration Years of data used S

28 Tittabawassee River near Saginaw 04156510 Dissolved oxygen (mg/L) 30 0 6.2 8.7 12.6 6 28 Tittabawassee River near Saginaw 04156510 Lead (μg/L) 31 0 0.11 0.425 2.53 6 28 Tittabawassee River near Saginaw 04156510 Mercury (ng/L) 31 0 0.48 1.86 6.95 6 28 Tittabawassee River near Saginaw 04156510 Nitrate (mg/L as N) 31 0 0.24 0.74 3.17 6 28 Tittabawassee River near Saginaw 04156510 Nitrite (mg/L as N) 31 1 0.008 0.017 0.039 6 28 Tittabawassee River near Saginaw 04156510 pH 31 0 7.3 8 8.2 6 28 Tittabawassee River near Saginaw 04156510 Total phosphorus (mg/L as P) 31 0 0.03 0.057 0.149 6 28 Tittabawassee River near Saginaw 04156510 Specific conductance (μS/cm) 31 0 377 633 1052 6 28 Tittabawassee River near Saginaw 04156510 Total Kjehldahl nitrogen (mg/L as N) 31 0 0.5 0.77 1.02 6 28 Tittabawassee River near Saginaw 04156510 Total suspended solids (mg/L) 31 2 4 16 91 6 28 Tittabawassee River near Saginaw 04156510 Turbidity (NTU) 31 1 1 8 63 6 28 Tittabawassee River near Saginaw 04156510 Water temperature (°C) 31 1 0 15.2 27.3 6 30 Au Sable River near Au Sable 04137500 Ammonia (mg/L as N) 75 0 0.002 0.014 0.031 6 30 Au Sable River near Au Sable 04137500 Chloride (mg/L) 77 0 5 6 34 6 30 Au Sable River near Au Sable 04137500 Chromium (μg/L) 77 33 0.001 0.057 0.884 -- 30 Au Sable River near Au Sable 04137500 Copper (μg/L) 77 0 0.106 0.225 0.588 6 30 Au Sable River near Au Sable 04137500 Dissolved oxygen (mg/L) 74 0 7.1 8.7 13.1 6 30 Au Sable River near Au Sable 04137500 Lead (μg/L) 77 0 0.0193 0.0386 0.121 6 30 Au Sable River near Au Sable 04137500 Mercury (ng/L) 77 2 0.01 0.28 4.579 6 30 Au Sable River near Au Sable 04137500 Nitrate (mg/L as N) 74 2 0.001 0.011 0.151 6 30 Au Sable River near Au Sable 04137500 Nitrite (mg/L as N) 76 1 0.001 0.002 0.005 6 30 Au Sable River near Au Sable 04137500 pH 76 0 7.3 7.95 8.7 6 30 Au Sable River near Au Sable 04137500 Total phosphorus (mg/L as P) 77 0 0.001 0.01 0.019 6 30 Au Sable River near Au Sable 04137500 Specific conductance (μS/cm) 74 0 253 295 747 6 30 Au Sable River near Au Sable 04137500 Total Kjehldahl nitrogen (mg/L as N) 77 0 0.009 0.19 0.37 6 30 Au Sable River near Au Sable 04137500 Total suspended solids (mg/L) 76 66 1 4 20 -- 30 Au Sable River near Au Sable 04137500 Turbidity (NTU) 65 62 0.4 1 1 -- 30 Au Sable River near Au Sable 04137500 Water temperature (°C) 77 0 0.7 17.5 25.9 6 

ogarty — Analysis of Water-Quality Trends for Selected Streams in the Water Chemistry Monitoring Program, MI, 1998–2005—SIR 2009–5216 

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