In cooperation with the McHenry County Soil and Water Conservation District

Water Quality of Nippersink Creek and Wonder Lake,

McHenry County, Illinois, 1994-2001

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2004-5085
Water Quality of Nippersink Creek and 

Wonder Lake, McHenry County, Illinois, 

1994-2001

By David H. Dupré and Dale M. Robertson

In cooperation with the McHenry County Soil and Water Conservation District

Scientific Investigations Report 2004-5085

U.S. Department of the Interior

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

Gale A. Norton, Secretary

U.S. Geological Survey

Charles G. Groat, Director

U.S. Geological Survey, Reston, Virginia: 2004

For sale by U.S. Geological Survey, Information Services

Box 25286, Denver Federal Center

Denver, CO 80225

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

World Wide Web: http://www.usgs.gov/

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

Cover photograph: Nippersink Creek above Wonder Lake, McHenry County, Illinois; view looking downstream from Thompson Road. 

Photograph by David H. Dupré.
iii

CONTENTS

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

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

Purpose and scope.............................................................................................................................. 4

Description of the study area ............................................................................................................ 4

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

Acknowledgments............................................................................................................................... 8

Hydrologic Conditions.................................................................................................................................. 8

Water Quality................................................................................................................................................. 9

Nippersink Creek above Wonder Lake............................................................................................. 9

Sediment ...................................................................................................................................... 9

Nutrients....................................................................................................................................... 9

Wonder Lake....................................................................................................................................... 21

Trophic State.............................................................................................................................. 21

Sediment Load........................................................................................................................... 22

Nippersink Creek below Wonder Lake........................................................................................... 25

Sediment .................................................................................................................................... 25

Nutrients..................................................................................................................................... 25

Summary and Conclusions........................................................................................................................ 27

Selected References.................................................................................................................................. 32

Figures

1-4. Maps showing−

 1. Location of the Nippersink Creek Basin in northeastern Illinois and 

 southeastern Wisconsin ..................................................................................................... 2

 2. Land use in the Nippersink Creek Basin, northeastern Illinois and 

 southeastern Wisconsin ..................................................................................................... 3

 3. Urbanization in the Nippersink Creek Basin, northeastern Illinois and 

 southeastern Wisconsin ..................................................................................................... 5

 4. Bathymetry of Wonder Lake, McHenry County, Ill., 1994............................................... 6

5-20. Graphs showing−

 5. Daily mean streamflow in Nippersink Creek above Wonder Lake, 

 McHenry County, Ill., June 1994 – September 2001...................................................... 10

 6. Daily mean streamflow in Nippersink Creek below Wonder Lake, 

 McHenry County, Ill., June 1994 – September 1997...................................................... 11

 7. Daily mean streamflow and sediment discharge in Nippersink Creek 

 above Wonder Lake, McHenry County, Ill., June 1994 – September 2001................ 13

 8. Nutrient concentrations in Nippersink Creek above Wonder Lake, 

 McHenry County, Ill., July 1994 –August 2001 ............................................................... 14

 
iv 

 9. Total phosphorus (as P) concentrations in Nippersink Creek above 

 Wonder Lake, McHenry County, Ill., by A) month of sample 

 and B) sampled flow .......................................................................................................... 15

 10. Dissolved phosphorus (as P) concentrations in Nippersink Creek 

 above Wonder Lake, McHenry County, Ill., by A) month of sample 

 and B) sampled flow .......................................................................................................... 16

 11. Dissolved ammonia (NH4 as N) concentrations in Nippersink Creek 

 above Wonder Lake, McHenry County, Ill., by A) month of sample 

 and B) sampled flow .......................................................................................................... 17

 12. Total ammonia plus organic nitrogen (NH4 + org. N as N) concentrations

 in Nippersink Creek above Wonder Lake, McHenry County, Ill., by 

 A) month of sample and B) sampled flow....................................................................... 18

 13. Dissolved nitrite plus nitrate (NO2 + NO3 as N) concentrations

 in Nippersink Creek above Wonder Lake, McHenry County, Ill., by 

 A) month of sample and B) sampled flow....................................................................... 19

 14. Water-quality data, Wonder Lake, McHenry County, Ill., April 15 – 

 August 1, 1999 ..................................................................................................................... 22 

 15. Water-quality data, Wonder Lake, McHenry County, Ill., February 9 – 

 August 9, 2000 ..................................................................................................................... 23

 16. Trophic state indices of Wonder Lake, McHenry County, Ill., April – 

 August 1999, and February – August 2000...................................................................... 24

 17. Daily mean streamflow and sediment discharge in Nippersink Creek 

 below Wonder Lake, McHenry County, Ill., June 1994 – September 1997................ 26

 18. Total and dissolved phosphorus (as P) concentrations in Nippersink

 Creek below Wonder Lake, McHenry County, Ill., July 1994 –July 1997 ................... 29

 19. Total phosphorus (as P) concentrations in Nippersink Creek below 

 Wonder Lake, McHenry County, Ill., by A) month of sample 

 and B) sampled flow .......................................................................................................... 30

 20. Dissolved phosphorus (as P) concentrations in Nippersink Creek below 

 Wonder Lake, McHenry County, Ill., by A) month of sample 

 and B) sampled flow .......................................................................................................... 31

Tables

1. Population change for the period 1970-2000 in McHenry County, Ill. ................................ 4

2. Annual runoff in Nippersink Creek above and below Wonder Lake, and 

 ungaged lake inflow volumes by percentage of lake outflow in Nippersink 

 Creek below Wonder Lake, McHenry County, Ill.................................................................... 8

3. Suspended-sediment and nutrient concentration statistics for Nippersink 

 Creek above Wonder Lake, McHenry County, Ill., 1994-2001 ............................................. 12

4. Regression coefficients, significance level, and goodness-of-fit parameters, 

 by calibration period, for nutrients in Nippersink Creek above Wonder Lake, 

 McHenry County, Ill. .................................................................................................................. 20
v

5. Estimated annual nutrient loads in tons from Nippersink Creek above 

 Wonder Lake, McHenry County, Ill. ........................................................................................ 21

6. Sediment load trapped within Wonder Lake, McHenry County, Ill., 1994-2001............... 25

7. Monthly suspended-sediment load in Nippersink Creek above and below 

 Wonder Lake, McHenry County, Ill. 1994-2001...................................................................... 27

8. Suspended-sediment and nutrient concentrations in Nippersink Creek below 

 Wonder Lake, McHenry County, Ill., 1994-97......................................................................... 28

9. Regression coefficients, significance level, and goodness-of-fit parameters, 

 by calibration period, for nutrients in Nippersink Creek below Wonder Lake, 

 McHenry County, Ill. .................................................................................................................. 32

10. Estimated annual total phosphorus retention in Wonder Lake, McHenry 

 County, Ill., by model calibration period................................................................................. 32
vi

Multiply By To obtain

Length

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 0.4047 hectare (ha)

acre 0.004047 square kilometer (km2)

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

cubic foot (ft3) 0.02832 cubic meter (m3) 

acre-foot (acre-ft) 1,233 cubic meter (m3)

inches per square mile (in/mi2) 0.981 centimeters per square kilometer 

(cm/km2)

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

Mass

ton 0.9072 metric ton 

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

 °F=(1.8×°C)+32

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

 °C=(°F-32)/1.8

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88). Historical data collected and stored as National Geodetic Vertical Datum of 1929 

(NGVD 29) have been converted to NAVD 88 for use in this publication.

Horizontal coordinate information is referenced North American Datum of 1983 (NAD 83). 

Historical data collected and stored as North American Datum of 1927 (NAD27) have been 

converted to NAD83 for use in this publication.

Altitude, as used in this report, refers to distance above or below sea level.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 

25 °C).

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

or micrograms per liter (μg/L). Milligrams per liter is a unit expressing the concentration of 

chemical constituents in solution as weight (milligrams) of solute per unit volume (liter) of water. 

One-thousand micrograms per liter is equivalent to one milligram per liter. For concentrations less 

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

Conversion Factors and Datums
Abstract

Wonder Lake, McHenry County, Illinois was 

formed when an earthen dam was constructed 

across Nippersink Creek in 1929. The U.S. Geological Survey (USGS), in cooperation with the 

McHenry County Soil and Water Conservation 

District, operated two streamflow and water-quality monitoring sites (upstream and downstream of 

Wonder Lake) from July 1994 through June 1997, 

and examined the water quality of the lake during 

1999-2000. From 1999 through 2001, the USGS 

National Water-Quality Assessment Program operated the same upstream monitoring station to assess 

the streamflow, sediments, nutrients, and other 

chemical and physical characteristics of Nippersink 

Creek. Interpolation and regression methods were 

used to compute loads of sediment and nutrients 

delivered to Wonder Lake through Nippersink 

Creek by the combination of data sets collected as 

part of these studies.

Since the formation of Wonder Lake, sediment 

and nutrient loading from Nippersink Creek has 

caused lake water-quality degradation. Wonder 

Lake effectively trapped 75 percent of the 15,900 

tons of suspended sediment delivered during 1994-

97. The average daily sediment load delivered 

during 1994-2001 was 25 tons. High sediment 

loading from the watershed reduces water clarity 

and hinders lake navigation. Nutrient loading from 

Nippersink Creek results in eutrophic conditions 

within Wonder Lake as evaluated on a Trophic State 

Index. The load of total phosphorus trapped in 

Wonder Lake is from 6 to 28 percent of the delivered load from Nippersink Creek. If the lake could 

be restored to its original capacity, the sediment 

trapping efficiency may be increased.

INTRODUCTION

The construction of an earthen dam across 

Nippersink Creek in 1929 created Wonder Lake, 

McHenry County, northeastern Illinois (fig. 1). This 

830-acre reservoir is incorporated into the Village 

of Wonder Lake and lies within the 97.0-mi2 watershed. Wonder Lake is important economically, 

socially, and ecologically to the area. Changes in 

lake-water quality are of chief concern to the sustainability of this area for recreational uses.

The water quality of lakes is affected by streams 

draining their watersheds (Leopold, Wolman, and 

Miller, 1964). This effect may be more pronounced 

in lakes or reservoirs with short water residence 

times, which usually are measured in months, rather 

than lakes or reservoirs with longer residence times, 

which usually are measured in years. The amounts 

of water, sediment, and nutrients delivered to Wonder Lake through Nippersink Creek are affected 

by many natural processes and human factors that 

are dynamic, rather than static, over time (Hack, 

1960). Residence times decrease as a reservoir fills 

with settled sediments. This decrease in residence 

time contributes to the dynamic nature of the lentic 

system.

Nitrogen and phosphorus are essential nutrients for primary productivity in freshwater aquatic 

systems; however, when these nutrients are in 

excess, they can promote extensive aquatic-plant 

growth (macrophytes, periphyton, and phytoplankton), which can lead to eutrophic (productive) 

conditions. Typically, the limiting growth factor 

for most aquatic plants and algae in the Midwest is 

phosphorus. Nitrogen availability also is important 

in algae growth. When these plants and algae die 

and decompose, the process consumes dissolved 

Water Quality of Nippersink Creek and Wonder Lake, 

McHenry County, Illinois, 1994-2001

By David H. Dupré and Dale M. Robertson
2 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

oxygen in the water (Westlake, 1975a). This cycle 

can decrease dissolved oxygen concentrations to 

less than 2 mg/L (hypoxic conditions) in lakes, 

especially in deeper areas of stratified lakes, during 

part of the year. Low dissolved oxygen concentrations are undesirable because rough-fish populations 

survive better than game-fish populations in this 

condition.

To help understand the causes of the degradation in the water quality of the lake, data from 

three U.S. Geological Survey (USGS) studies were 

combined and examined. The USGS, in cooperation 

with the McHenry County Soil and Water Conservation District (SWCD), operated two streamflow 

and water-quality monitoring sites (one upstream of 

the lake and one downstream of the lake) 

(fig. 2) from July 1994 through June 1997, and 

examined the water quality of Wonder Lake during 

1999-2000. From 1999 through 2001, the USGS 

National Water-Quality Assessment (NAWQA) Program operated one monitoring station (the upstream 

site) to assess the streamflow, sediments, nutrients, 

and other chemical and physical characteristics of 

Nippersink Creek. Data collected at the monitoring 

stations during these studies were used to calculate loads of sediment, nitrogen, and phosphorus 

delivered to Wonder Lake from Nippersink Creek 

during Water Years (WY) 1995-2001. A WY is the 

12-month period from October 1 through September 

30, and is designated by the calendar year in which 

it ends.

Cochran and Wilken, Inc. (1996) summarized 

past water-quality studies on the lake and estimated the amount of sediment deposited within 

Figure 1. Location of the Nippersink Creek Basin in northeastern Illinois and southeastern Wisconsin.
Figure 2. Land use in the Nippersink Creek Basin, northeastern Illinois and southeastern Wisconsin.

Introduction 3
4 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

the lake since 1929. Prior to 1994, studies on the 

lake focused on water quality and fish biodiversity 

within the lake; no efforts were made to document 

the streamflow or delivery of sediment and nutrients 

to Wonder Lake.

Purpose and Scope

This report describes the water quality of Wonder Lake and Nippersink Creek, McHenry County, 

Illinois. Sediment and nutrient data were collected 

during 1994-97 and 1999-2001. The sediment trapping efficiency of Wonder Lake is estimated for the 

period 1994-97. The water-quality conditions of the 

lake are evaluated with a Trophic State Index (TSI) 

with data collected in 1999 and 2000. The data 

collected as part of these studies were combined for 

analysis in this report. Annual loads of sediment 

were calculated using an interpolation technique 

and annual loads of nutrients were computed with 

multivariate regression techniques.

Description of the study area

Wonder Lake is in the upper Fox River Subbasin of the upper Illinois River Basin (fig. 1). 

Wonder Lake is on the main branch of Nippersink 

Creek, 17 river miles upstream of the Fox River 

(Healy, 1979). Wonder Lake’s watershed area is 

97.0 mi2.

The watershed area of Nippersink Creek at the 

monitoring station above Wonder Lake (station 

05548105, fig. 2) is 84.5 mi2, and includes parts of 

Walworth County, Wisconsin and McHenry County, 

Illinois. The station at Nippersink Creek below 

Wonder Lake (station 05548110, fig. 2) has a 

97.3 mi2 watershed area, and about 0.3 mi2 does not 

contribute drainage to the lake. 

The 1990 land use upstream of Wonder Lake is 

86.9 percent agricultural, and 4.4 percent urban 

(fig. 2; Vogelmann and others, 2001). Changes in 

urban areas from 1970 through 1990 are shown in 

figure 3 (Arnold and others, 1999). Changes in 

population from 1970 through 2000 are given in 

table 1. There was a 133 percent overall increase 

in McHenry County population between 1970 and 

2000 (U.S. Bureau of the Census, 1991 and 2003).

If the trend in population within McHenry 

County is similar to that in the Wonder Lake watershed, there will be a larger urban land usage within 

the Wonder Lake watershed. The construction of 

roads, homes, and municipal infrastructure was 

evident during multiple visits to the area during the 

course of the study.

Originally, Wonder Lake was planned to be 75 

percent of its present size. A possible surveying 

error may be the cause of the difference in lake size. 

The entire South Bay area was not anticipated to be 

under water (fig. 4). Because of this possible error, 

the present lakefront property includes lots that 

were not designed as part of the initial development 

(Richard Hilton, Master Property Owner’s Association of the Wonder Lake Area, oral commun., 

2001). These differences from the original plans 

contribute to the management and decision-making 

processes within the watershed and with its stakeholders.

Methods

Two streamflow monitoring stations were 

installed on Nippersink Creek in 1994, one above 

and one below Wonder Lake, to monitor stage and 

establish a discharge rating using standard USGS 

protocols (Rantz and others, 1982). These stations were in operation from July 1994 through 

June 1997 (Gary Johnson, U.S. Geological Survey, oral commun., 2001). The USGS NAWQA 

Program operated the station upstream of Wonder 

Lake during 1999 - September 2001. The USGS 

did not operate the downstream station after 1997. 

Three other intermittent streams (Galt Creek, Deep 

Spring Creek, and Wooded Shore Creek) contribute 

Table 1. Population change for the period 1970-2000 in McHenry 

County, Ill. (modified from Arnold and others, 1999). 

[%, percent]

Population

1970 1980 1990 2000

111,456 147,897 183,241 260,077

Change in population

1970-80 1980-90 1990-2000 1970-2000

32.7% 23.9% 41.9% 133%
Figure 3. Urbanization in the Nippersink Creek Basin, northeastern Illinois and southeastern Wisconsin.

Introduction 5
6 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

Figure 4. Bathymetry of Wonder Lake, McHenry County, Ill., 1994.
directly to Wonder Lake (fig. 4). Because of study 

limitations, streamflow magnitude and duration 

were not measured in these tributaries. The annual 

flow into Wonder Lake from these tributaries is not 

considered substantial.

To calculate nutrient mass loadings from 1994 

through 1999, streamflow needed to be estimated at 

the station above Wonder Lake for WY 1998. Flow 

estimation was accomplished by extrapolating flow 

data from another station on Nippersink Creek, 12.3 

river miles downstream (Nippersink Creek near 

Spring Grove), by use of a drainage-area ratio. The 

watershed area at the station above Wonder Lake 

is 44 percent of the area measured near Spring 

Grove. Similarly, the mean daily discharge during 

the period of record above Wonder Lake also was 

44 percent of the mean daily discharge near Spring 

Grove. Therefore, this extrapolation method should 

approximate the annual streamflow conditions for 

WY 1998 (Gary Johnson, U.S. Geological Survey, 

oral commun., 2001).

Sediment and nutrient samples were collected 

using the equal-width-increment (EWI) method 

(Guy, 1970; Edwards and Glysson, 1988; Shelton, 

1994). Additional grab samples were collected by 

local observers, as well as with an automated sampler using a fixed-interval, fixed-volume technique 

(Guy, 1970; Porterfield, 1972; Edwards and Glysson, 1988; Shelton, 1994; Johnson, 1997). The grab 

samples were necessary during periods when EWI 

sampling was not possible, and during periods when 

no observers were available. Grab samples were not 

collected during 1999-2001. Analyses for dissolved 

constituents were performed on samples filtered in 

the field through a 0.45 μm (micrometer) pore-size 

filter. Suspended sediment and total constituents 

were determined by analyzing unfiltered water 

samples (Guy, 1969). The USGS National WaterQuality Laboratory (NWQL) performed chemical 

analyses of water samples using standard analytical 

methods (Wershaw and others, 1987; Fishman and 

Friedman, 1989; Fishman, 1993). The suspendedsediment samples were analyzed at the USGS 

Kentucky or Missouri District sediment laboratories 

using standard techniques (Guy, 1969; Sholar and 

Shreve, 1998).

Annual loads of suspended sediment were 

estimated using Graphical Constituent Loading 

and Analysis Software (GCLAS) where methods 

described by Porterfield (1972) are applied. A 

menu-driven interface is used in GCLAS to access 

computer algorithms that linearly interpolate 

between log-transformed, instantaneous suspendedsediment concentrations stored at unequal time 

intervals (Gary Johnson, U.S. Geological Survey, 

oral commun., 2001). Daily suspended-sediment 

loads then are estimated from the interpolated, logtransformed data. The amount of sediment deposited in Wonder Lake was estimated by subtracting 

the mass leaving in Nippersink Creek below Wonder Lake from the mass that entered the lake from 

Nippersink Creek above Wonder Lake.

Annual loads of total phosphorus, dissolved 

phosphorus, ammonia plus organic nitrogen, dissolved ammonia, and dissolved nitrite plus nitrate 

were calculated using a regression technique 

within the Estimator program (Cohn and others, 

1989). The Minimum Variance Unbiased Estimator 

(MVUE) is used to correct for log-transformation 

biases (Cohn and others, 1989; Gilroy and others, 

1990; Cohn and others, 1992a). Daily loads are calculated in the Estimator program using streamflow, 

time, and seasonality (expressed as sine and cosine 

transformations of time) as explanatory variables. 

In this analysis, one-half of the laboratory Method 

Reporting Level (MRL) was chosen to represent 

observed values reported as above zero yet below 

the MRL.

The regression equation for each constituent has 

the form

ln (CQ) = β0 + β1*ln (Q) + β2*T + β3*(2*π*T) + β4*(2*π*T), (1)

where

C = concentration,

β0, β1, β2, β3, β4 = empirical coefficients,

Q = daily mean streamflow,

T = time, and,

π = 3.1416.

Water-column profiles for dissolved oxygen, 

water temperature, pH, and specific conductance 

were obtained by measuring at half-meter intervals 

from the surface to the lake bottom using a multiparameter meter. The meter was calibrated in the 

Introduction 7
8 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

field with standard reference solutions for pH and 

specific conductance prior to measurement. The 

saturated air-calibration method was used for the 

dissolved-oxygen sensor (Robertson and others, 

1999).

A Secchi disk was used to measure water clarity (Cole, 1994). This 20-centimeter-diameter disk 

has alternating quadrants of black-and-white, and 

is lowered through the water column until it disappears from sight. This depth of disappearance is 

recorded as the Secchi depth.

Grab samples of lake water were collected 

1-2 ft below the water surface using a Van Dorn 

sampler (Field and others, 1995). Unfiltered samples were analyzed for total phosphorus and chlorophyll a concentrations. All lake samples were analyzed by the Wisconsin State Laboratory of Hygiene 

using the same techniques as utilized by the NWQL 

(Wisconsin State Laboratory of Hygiene, 1993).

One method of classifying the trophic state of a 

lake is by computing individual index values based 

on near-surface total P and chlorophyll a concentrations, and Secchi depths, as developed by Carlson 

(1977) and modified by Lillie and others (1993). 

These indices were developed to place these three 

water-quality characteristics on similar scales. TSI 

values for a lake can be calculated using the following equations (Lillie and others, 1993):

TSISD = 60.0 – 33.2 (log10 Secchi depth, in meters) (2)

TSIC = 34.82 + 17.41 (log10 chlorophyll a concentrations, in micrograms per liter) (3)

TSITP = 28.24 + 17.81 (log10 total phosphorus concentrations, in 

micrograms per liter) (4)

Acknowledgments

The authors wish to thank the Master Property 

Owner’s Association of Wonder Lake, Ill., and 

specifically Richard Hilton and Tom Cooper of the 

Association. Peter Berrini of Cochran and Wilken, 

Inc. provided lake drawings and maps, as well as 

historical information. The following USGS personnel are noted for their assistance in the planning 

and execution of this study, and mentoring during 

the course of this study: Gary Johnson, Kevin Richards, George Groschen, and Mike Friedel.

HYDROLOGIC CONDITIONS

The annual mean streamflow in Nippersink 

Creek above Wonder Lake is 62.7 ft3/s for the 

period of record from 1995 to 2001, which indicates 

annual runoff of about 10 in/mi2 (Harris and others, 2002). The flow regime varied greatly between 

the monitored periods, 1994-97 and 1999-2001, 

as indicated by the annual runoff at the upstream 

monitoring site (table 2). The period from 1995 to 

1997 was much drier than normal with each successive year slightly wetter than the preceding year. 

The wettest year during the study period was 1999, 

with 2000 also much wetter than normal. WY 2001 

was close to the mean of 10.1 in/mi2 or 62.7 ft3/s. 

The combination of these hydrologic data from the 

two streamgaging periods should provide acceptable 

range for the constituent load estimates.

Based on the observed streamflow in Nippersink Creek below Wonder Lake, there are 

unmeasured inputs into Wonder Lake (table 2). 

The magnitude of these inputs is estimated to be 

no more than 12-15 percent of the volume exiting 

Table 2. Annual runoff in Nippersink Creek above and below 

Wonder Lake, and ungaged lake inflow volumes by percentage of 

lake outflow in Nippersink Creek below Wonder Lake, McHenry 

County, Ill. 

[nd, no data]

Annual Runoff

Above Wonder Lake Below Wonder Lake

Water Years (inches per 

square mile)

(inches per 

square mile)

1995 6.30 6.43

1996 8.78 8.69

1997 9.29 9.25

1998 110.56 nd

1999 13.83 nd

2000 12.15 nd

2001 10.18 nd

Mean 1995-2001 10.09 8.12

Estimated ungaged 

inflows Percentage of 

outflow Water Years (millions of cubic feet)

1995 79,200 14.9

1996 88,100 12.3

1997 97,400 12.8

1

Calculated value; not included in Mean.
the lake annually. There are three, small intermittent creeks (Galt Creek, Deep Spring Creek, and 

Wooded Shore Creek) that drain into Wonder Lake 

that may account for the majority of this volume 

(fig. 4). Other sources of flow and input to the 

lake not considered here are ground-water inflow 

(including septic fluxes), direct precipitation and 

evapotranspiration, and adjacent impervious areas. 

Wonder Lake has an additional 12.5 mi2 (total area 

is 97.0 mi2) of watershed area than does the gaging station above the lake (05548105, fig. 2). The 

Nippersink Creek station below the lake (05548110) 

has 0.3 mi2 of drainage not contributing to the lake.

The flows in Nippersink Creek above and 

below Wonder Lake are shown in figures 5 and 6, 

respectively. These flows were used as model input 

for estimating sediment and nutrient loads in Nippersink Creek and Wonder Lake. These loads are 

discussed in the section Water Quality below.

WATER QUALITY

The discussion of water quality presented here 

is divided into three parts: water quality of Nippersink Creek above Wonder Lake, water quality 

of Wonder Lake, and water quality of Nippersink 

Creek below the lake. The creek-lake system then 

can be evaluated from an input-output viewpoint for 

those periods of time of concurrent observations.

Nippersink Creek above Wonder Lake

Descriptions of the observed concentrations and 

calculated loads of suspended sediment and nutrients are described below. These concentrations and 

loads represent the inputs to Wonder Lake.

Sediment

Daily-mean suspended-sediment concentrations 

in Nippersink Creek above Wonder Lake from July 

1994 through July 2001 ranged from 1.2 mg/L to 

808 mg/L, with a mean concentration of 

89.3 mg/L (table 3). Suspended-sediment concentration generally is related to streamflow (fig. 

7). Further discussion of sediment concentration 

is found in the section below on sediment loads in 

Wonder Lake. Mass loads were calculated from the 

concentration data. The load in Nippersink Creek 

was evaluated above and below Wonder Lake to 

estimate the amount trapped within the lake.

Nutrients

Total phosphorus concentrations ranged from 

0.020 to 1.16 mg/L, with a mean concentration of 

0.159 mg/L (table 3). The highest concentrations 

were observed in the spring; lower concentrations 

were observed throughout the year. Total phosphorus concentrations generally increased with increasing streamflow. Comparisons between observed 

constituent concentration and month of sample, and 

discharge at time of sampling for each nutrient collected in Nippersink Creek above Wonder Lake are 

shown in figures 8-13.

Dissolved phosphorus concentrations ranged 

from 0.005 to 0.188 mg/L, with a mean concentration of 0.044 mg/L (table 3, fig. 10). Eight values 

were below the MRL, 0.010 mg/L. Dissolved phosphorus concentrations were positively correlated 

to streamflow. There was no strong seasonality in 

dissolved phosphorus concentrations at this site 

(05548105).

The concentrations of dissolved ammonia as 

nitrogen (hereinafter referred to as “ammonia”) 

from March 1999 through August 2001 ranged from 

0.010 to 0.228 mg/L (table 3, fig. 11). The NWQL’s 

MRL changed toward the end of the study to less 

than 0.041 mg/L that affected four samples being 

reported as less than the revised MRL. There were 

16 of 37 water samples that were reported as below 

a MRL for ammonia. Ammonia concentrations had 

slight seasonality with highest concentrations in the 

spring. The concentrations of ammonia increased 

with increasing flow for flows less than 400 ft3/s; 

however, above this flow there was a weak negative 

relation.

Concentrations of ammonia-plus-organic 

nitrogen as nitrogen (hereinafter referred to as 

“total organic nitrogen”) from March 1999 through 

August 2001 ranged from 0.31 to 4.2 mg/L, with a 

mean concentration of 1.1 mg/L (table 3, figure 12). 

Although the highest total organic nitrogen concentrations were observed in the spring, lower concentrations were observed throughout the period. 

Water Quality 9
10 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

Figure 5. Daily mean streamflow in Nippersink Creek above Wonder Lake, McHenry County, Ill., June 1994 − September 2001.
Figure 6. Daily mean streamflow in Nippersink Creek below Wonder Lake, McHenry County, Ill., June 1994 − September 1997.

Water Quality 11
12 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001 Skewness 2.3 1.31 2.1.862 .680 3.30 1.97 Variance 5,710.005 1.0 3.75 .000 .031 .002 Standard Dev. 75.6.068 1.0 1.94 .016 .177 .039 Max 808.228 4.2 9.00 .067 1.16 .188 Percentile 90th 192.193 2.4 7.58 .057 .277 .090 75th 121.095 1.3 5.39 .044 .208 .051 50th 63.0.036 .66 3.87 .026 .100 .034 25th 36.5.010 .44 2.91 .020 .060 .020 10th 25.2.010 .39 2.43 .015 .040 .010 Min or one- half the MRL 1.2.010 .31 2.27 .010 .020 .005 Mean 89.3.066 1.1 4.42 .032 .159 .044 Number of Samples 199037373737 11495 Daily-Mean Suspended Sediment (mg/L) Dissolved Ammonia (NH4 as N) (mg/L) Total Ammonia + Organic N as N (mg/L) Dissolved Nitrite (NO2) + Nitrate (NO3) as N (mg/L) Dissolved Nitrite (NO2 as N) (mg/L) Total Phosphorus as P (mg/L) Dissolved Phosphorus as P (mg/L) Table 3. Suspended-sediment and nutrient concentration statistics for Nippersink Creek above Wonder Lake, McHenry County, Ill., 1994-2001. [mg/L, milligrams per liter; min, minimum; MRL, method reporting level; max, maximum; Dev., deviation]
Water Quality 13Figure 7. Daily mean streamflow and sediment discharge in Nippersink Creek above Wonder Lake, McHenry County, Ill., June 1994 – September 2001.
14 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

Figure 8. Nutrient concentrations in Nippersink Creek above Wonder Lake, McHenry County, Ill. July 1994 

− August 2001.
Figure 9. Total phosphorus (as P) concentrations in Nippersink Creek above Wonder Lake, McHenry County, Ill., by A) month of sample 

and B) sampled flow.

Water Quality 15
16 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

Figure 10. Dissolved phosphorus (as P) concentrations in Nippersink Creek above Wonder Lake, McHenry County, Ill., by A) month of 

sample and B) sampled flow.
Figure 11. Dissolved ammonia (NH4 as N) concentrations in Nippersink Creek above Wonder Lake, McHenry County, Ill., by A) month of 

sample and B) sampled flow.

Water Quality 17
18 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

Figure 12. Total ammonia plus organic nitrogen (NH4 + org. N as N) concentrations in Nippersink Creek above Wonder Lake, McHenry 

County, Ill., by A) month of sample and B) sampled flow.
Figure 13. Dissolved nitrite plus nitrate (NO2 + NO3 as N) concentrations in Nippersink Creek above Wonder Lake, McHenry County, Ill., 

by A) month of sample and B) sampled flow.

Water Quality 19
20 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

Similar to ammonia concentrations, total organic 

nitrogen concentrations increased with increasing 

flow for flows less than 400 ft3/s. For flows greater 

than 900 ft3/s, there may be negative relation to 

concentration.

Concentrations of dissolved nitrite plus nitrate 

as nitrogen (hereinafter referred to as “nitrate”) 

from March 1999 through August 2001 ranged 

from 2.27 to 9.00 mg/L, with a mean concentration 

of 4.42 mg/L (table 3, fig. 13). Although the highest nitrate concentrations were observed in spring, 

lower concentrations were observed throughout 

the period. Similar to ammonia and total organic 

nitrogen concentrations, nitrate concentrations 

increased with increasing flow up to 400 ft3/s, and 

then decreased with higher flow.

The same water samples taken in Nippersink 

Creek above Wonder Lake were analyzed for nitrite 

as nitrogen (hereinafter referred to as “nitrite”) 

concentrations. Generally, nitrite concentrations 

were two orders of magnitude lower than the nitrate 

concentrations and are, therefore, considered negligible (table 3).

Constituent concentrations and coinciding 

daily streamflow were used to develop multivariate models (described in equation 1 above) with 

time and streamflow regressors to estimate nutrient 

loads. Regression coefficients, p-values for statistically significant parameters, and goodness-of-fit 

measures, as well as the model-calibration period, 

are listed in table 4 for the Nippersink Creek loadprediction models. Each phosphorus parameter was 

calibrated twice.

It was necessary to calibrate two regression 

equations for phosphorus data to accurately compare the various study phases because of varying 

hydrologic conditions. This calibration was completed in an attempt to estimate an annual phosphorus load trapped in the lake. The equation that 

better explained observed variability was used to 

calculate loads. The annual nutrient loads estimated 

in Nippersink Creek above Wonder Lake based on 

the 1999-2001 calibration, and the corresponding 

95-percent confidence intervals are listed in table 5.

The total phosphorus, dissolved phosphorus, 

and total organic nitrogen models better described 

the variability in loading than the nitrate and ammoTable 4. Regression coefficients, significance level, and goodness-of-fit parameters, by calibration period, for nutrients in Nippersink 

Creek above Wonder Lake, McHenry County, Ill.

[r 2, explained variability; %, percent; S, standard error; >, greater than]

Nutrient

(Calibration period)

Model Coefficient 

(p-value) r 2

(%) S

β0 β 1 β 2 β 3 β 4

Total

Organic Nitrogen 

(1999-2001)

5.854 1.425 0 0.212 -0.106

95.0 0.42

(0.000) (0.000) (>0.05) (0.072) (0.298)

Dissolved Ammonia 

(1999-2001)

2.936 1.526 0 .471 .349

84.1 .84

(0.000) (0.000) (>0.05) (0.048) (0.093)

Dissolved Nitrate

(1999-2001)

7.247 1.119 0 0 0

77.9 .71

(0.000) (0.000) (>0.05) (>0.05) (>0.05)

Total Phosphorus

(1999-2001)

4.022 1.643 0 .201 -.279

94.8 .50

(0.000) (0.000) (>0.05) (0.151) (0.026)

Dissolved Phosphorus 

(1999-2001)

3.029 1.638 0 -.337 -.157

94.8 .46

(0.000) (0.000) (>0.05) (0.011) (0.164)

Total Phosphorus

(1994-97)

2.554 1.342 0 -.271 -.535

85.9 .59

(0.000) (0.000) (>0.05) (0.030) (0.000)

Dissolved Phosphorus 

(1994-97)

1.365 1.342 0 0 0

75.1 .82

(0.000) (0.000) (>0.05) (>0.05) (>0.05)
nia models as indicated by the higher percentage of 

explained variability (r2) and smaller standard errors 

(S) (table 4). Suspended material generally is better 

related to flow than dissolved constituents. Visual 

inspection of the data confirms this observation 

(figs. 7, 9, 12). Dissolved phosphorus, however, has 

a good fit for inputs to Wonder Lake in contrast to 

the poor fit for dissolved nitrogen forms. The dissolved phosphorus concentrations tended to increase 

with increasing flow, whereas the dissolved nitrogen 

forms did not (figs. 10, 11, 13).

WONDER LAKE

Wonder Lake was sampled nine times from 

April 1999 through August 2000 (Harris and others, 

2002). Vertical depth profiles of water temperature, 

dissolved oxygen, pH, and specific conductance collected during each sampling are presented graphically in figures 14 and 15. These seasonal profiles 

indicate that Wonder Lake intermittently mixes 

throughout the year, and no appreciable stratification takes place for extended periods. The trophic 

state of Wonder Lake was evaluated along with the 

physical properties previously mentioned.

Trophic State

Spring (April-May) Secchi depth in Wonder 

Lake was about 2 ft in both 1999 and 2000. The 

mean summer (June-August), or growing season, 

Secchi depth was about 1.5 ft during the study. The 

mean chlorophyll a concentration during the study 

was 62 μg/L, with a growing-season mean of 69 

μg/L. The mean near-surface, total phosphorus 

concentration during the study was 145 μg/L. The 

mean total phosphorus concentration for the growing season was 162 μg/L.

The lowest water-clarity measurement corresponded with the highest total phosphorus concentration observation in June 1999. This observation was on the day following the peak flow in 

Nippersink Creek for 1999. This observation may 

indicate that under large flow inputs, Wonder Lake 

becomes well mixed with a large amount of suspended sediment. These well-mixed lake conditions 

would disrupt or destroy any thermal stratification 

as well as dissolved-oxygen stratification for days 

to weeks. The depth profiles of the water column 

indicate periods of this lack of stratification 

(figs.14-15).

TSI index values were calculated to place these 

three characteristics on similar scales using equations 2, 3, and 4 as described above. Oligotrophic 

lakes (TSI values less than 40) have a limited supply of nutrients, typically are clear with low algal 

populations and P concentrations, and they typically 

contain oxygen throughout the year in their deepest parts. Mesotrophic lakes (TSI values between 

40 and 50) have a moderate supply of nutrients, are 

not especially clear, and are prone to moderate algal 

blooms; occasional oxygen depletions in the deeper 

Table 5. Estimated annual nutrient loads in tons from Nippersink Creek above Wonder Lake, McHenry County, Ill. 

[All loads in tons; annual 95-percent confidence interval value in brackets]

Nutrient

Water Years (Oct. 1 – Sept. 30)

Mean Median

1996 1997 1998 1999 2000 2001

Total Organic 

Nitrogen

62.97

[6.81]

67.41

[8.85]

66.82

[5.76]

135.8

[23.04]

114.7

[18.15]

63.88

[6.79] 85.26 67.11

Dissolved 

Ammonia

3.77

[0.91]

5.82

[2.11]

4.94

[0.99]

9.35

[3.25]

6.88

[2.36]

5.56

[1.61] 6.05 5.69

Dissolved Nitrate 264.4

[41.3]

281.2

[46.4]

313.8

[44.0]

445.3

[90.4]

388.1

[76.3]

303.0

[44.3] 332.60 308.40

Total Phosphorus 12.41

[1.89]

12.42

[2.36]

11.02

[1.21]

33.25

[8.83]

27.76

[6.64]

10.23

[4.74] 17.85 12.41

Dissolved

Phosphorus

3.36

[0.43]

3.40

[0.57]

3.00

[0.28]

9.08

[2.18]

7.82

[1.65]

2.96

[0.36] 4.94 3.38

Water Quality 21
22 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

parts of the lake are possible. Eutrophic lakes (TSI 

values greater than 50) are nutrient rich with possible corresponding water-quality problems, such as 

frequent seasonal algal blooms; oxygen depletion is 

common in the deeper parts of the lake and clarity is 

poor. 

The TSI values for Wonder Lake all fall in the 

range for eutrophic lakes (greater than 50), except 

for two chlorophyll a samples in June and July 

1999, which indicate mesotrophic conditions 

(fig. 16). These two chlorophyll a samples may be 

considered data outliers, as the June and July samples from the following year (2000) were an order 

of magnitude higher in concentration, and close to 

the median value for all observations. Additionally, the June and July 1999 samples followed major 

flow events from Nippersink Creek (fig. 5). The 

lake likely was flushed with this incoming water, 

and flowing waters typically have lower chlorophyll a concentration than slower-moving lake 

waters. Wonder Lake is a highly eutrophic system 

based on these TSI values.

Sediment Load

The amount of sediment trapped in Wonder 

Lake was estimated by subtracting the mass leaving 

in Nippersink Creek below Wonder Lake from the 

mass that entered the lake from Nippersink Creek 

above Wonder Lake. These sediment discharge data 

Figure 14. Water-quality data, Wonder Lake, McHenry County, Ill., April 15 – August 1, 1999.
Figure 15. Water-quality data, Wonder Lake, McHenry County, Ill., February 9 – August 9, 2000.

Water Quality 23
24 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

were published by the USGS (LaTour and others, 

2001; Harris and others, 2002). Annual sediment 

loads and retention are presented on a water-year 

basis (table 6). 

Stream and sediment discharge graphs for each 

station on Nippersink Creek are shown in figures 7 

and 17. Monthly sediment loads are given in table 

7. Wonder Lake trapped almost 75 percent of the 

sediment delivered through Nippersink Creek from 

July 1994 through June 1997.

The 75-percent trapping efficiency of Wonder 

Lake follows the relation observed by Brune (1953) 

for many other normally ponded reservoirs. Trapping efficiency is calculated from the capacity 

(C) to inflow (I) ratio. The estimated 1994 volumetric capacity of Wonder Lake is 3,600 acre-ft 

(Cochran and Wilken, Inc., 1996). The mean daily 

inflow of 62.7 ft3/s is equivalent to 124 acre-ft/d, 

which results in a C / I ratio of 0.079. Based on 

this Brune’s curve ratio, the trapping efficiency of 

Wonder Lake should be from 70 to 90 percent. As 

a reservoir fills, its trapping efficiency decreases. 

The 74-year old Wonder Lake is approximately 33 

percent filled from its 1929 volume (Cochran and 

Wilken, Inc., 1996). If Wonder Lake was dredged 

and its volume increased in the future, it is likely 

that it will trap a greater percentage of the delivered 

sediment load. 

Figure 16. Trophic state indices of Wonder Lake, McHenry County, Ill., April – August 1999, and February – August 2000.
It is estimated that a similar amount of sediment was delivered to Wonder Lake in WY 2000 

alone as had been delivered between June 1994 and 

June 1997 (table 5). Throughout the study, which 

encompassed 1,990 days, the estimated average 

daily sediment load is 25 tons. This daily loading 

would indicate an average annual sediment load of 

9,145 tons. If the 75-percent sediment-trapping rate 

applies in an average year, then about 6,800 tons of 

sediment would be trapped within Wonder Lake in a 

typical year. 

Nippersink Creek below Wonder Lake

Descriptions of the observed concentrations 

and calculated loads of suspended sediment and 

nutrients at Nippersink Creek below Wonder Lake, 

approximately 0.5 mi downstream of the Wonder 

Lake dam, are described below. These concentrations and loads represent the outputs from Wonder 

Lake.

Sediment

Suspended-sediment concentrations in Nippersink Creek below Wonder Lake from July 1994 

to June 1997 ranged from 3.1 to 90 mg/L, with a 

mean concentration of 19.1 mg/L (table 8). These 

concentrations correspond to those observed 

upstream of the lake during the same period, given 

the trapping effect, and relate positively to discharge 

(fig. 17). 

Nutrients

The concentrations of total phosphorus ranged 

from 0.020 to 1.81 mg/L with a mean concentration of 0.152 mg/L (table 3, fig. 18). Total phosphorus concentrations were not strongly related to 

flow or season, however, the maximum observation 

occurred with the largest discharge sampled during 

the 1994-97 study period (fig. 19).

Dissolved phosphorus concentrations ranged 

from 0.005 to 0.541 mg/L with a mean concentration of 0.045 mg/L (table 3, fig. 18). Dissolved 

phosphorus concentrations had a weak positive 

relation to increasing flow but no seasonality. The 

maximum observed value occurred with the highest-sampled event as it did with total phosphorus 

(fig. 20).

The loading models (table 9) do not explain 

the variability in daily loads below the lake as they 

did above the lake. The models calibrated with the 

1994-97 data for total phosphorus above and below 

Wonder Lake were reasonably accurate to estimate the amount of phosphorus retained in the lake 

during that time period. Similar comparisons for 

dissolved phosphorus would be highly variable, as 

model simulation only can account for 49 percent of 

the observed variability for that constituent.

Using the model calibrated with total phosphorus data in Nippersink Creek above and below 

Wonder Lake from 1994 to 1997, an estimate is 

made of the amount trapped within the lake (table 

10). There was about 6 percent of the mean annual 

Table 6. Sediment load trapped within Wonder Lake, McHenry County, Ill., 1994-2001. 

[%, percent; nd, no data.]

Water Year(s) Number of days

monitored

In

(tons)

Out

(tons)

Trapped = In - Out 

(tons)

Trapped

(%)

1994 102 207.9 95 112.9 54.3

1995 365 3,568 786 2,781 78

1996 366 4,815 1,435 3,380 70.2

1997 273 7,336 1,738 5,598 76.3

1994-97 1,106 15,927 4,055 11,872 74.5

1998 0 nd nd nd nd

1999 214 7,177 nd nd nd

2000 366 15,981 nd nd nd

2001 304 10,741 nd nd nd

Water Quality 25
2

6 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

Figure 17. Daily mean streamflow and sediment discharge in Nippersink Creek below Wonder Lake, McHenry County, Ill., June 1994 – September 1997.
total phosphorus load retained in Wonder 

Lake using the earlier data set. This esti-

mated trapping increases to 28 percent 

when the mean annual total phosphorus 

loading amount is used based on the latter 

calibration (tables 5 and 10). The differ-

ence in estimated total phosphorus trap-

ping is attributable solely to the differences 

between the two models for Nippersink 

Creek above Wonder Lake.

Results for the percent retained for total 

phosphorus delivered to Wonder Lake were 

appreciably different for the two models. 

Based on the sediment-trapping efficiency, 

and the observed relation between flow 

and concentrations of particulate nutrients, 

it would be expected that a larger percent-

age of total phosphorus would be retained 

within the lake, similar to suspended sedi-

ment. 

Three intermittent streams contribute 

directly to Wonder Lake (fig. 4). Because 

of study limitations, the flow magnitude and 

duration were not measured in these tribu-

taries. Therefore, slightly more sediments 

and nutrients may be delivered and retained 

than are estimated here. Flow inputs are 

best estimated when both Nippersink Creek 

monitoring sites are in operation upstream 

and downstream of Wonder Lake.

SUMMARY AND CONCLUSIONS

Wonder Lake, McHenry County, 

Illinois was formed when an earthen dam 

was constructed across Nippersink Creek 

in 1929. The USGS, in cooperation with 

the McHenry County SWCD, operated two 

streamflow and water-quality monitoring 

sites from July 1994 through June 1997, 

and examined the water quality of Won-

der Lake during 1999-2000. From 1999 

through 2001, the USGS NAWQA Program 

operated the same upstream monitoring 

station to assess the streamflow, nutrients, 

sediments, and other chemical and physical 

characteristics of Nippersink Creek.

Table 7. Monthly suspended-sediment load in Nippersink Creek above and below Wonder Lake, McHenry County, Ill. 1994-2001.[nd, no data]

Nippersink Creek above Wonder Lake (05548105)

Water Year October November December January February March April May June July August September

1994 nd nd nd nd nd nd nd nd nd 63.1 62.0 32.71995 36.4 162 152 650 72.9 207 1,190 579 137 75.0 254 53.31996 90.5 294 108 179 89.2 82.8 338 1,900 1,180 401 121 27.01997 64.8 89.8 160 178 3,020 590 246 942 2,050 232 47.4 45.01998 nd nd nd nd nd nd nd nd nd nd nd nd1999 nd nd nd nd nd 227 1,080 1,830 3,400 417 105 1142000 168 77.9 352 392 542 346 1,840 3,190 7,590 995 220 2652001 392 993 566 499 3,360 1,060 1,140 970 1,260 516 nd nd

Nippersink Creek below Wonder Lake (05548110)

Water Year October November December January February March April May June July August September

1994 nd nd nd nd nd nd nd nd nd 24.8 32.0 15.41995 19.7 78.8 56.8 79.5 54.1 61.2 159 147 51.0 36.2 29.7 14.31996 21.3 72.8 65.0 87.1 57.0 27.4 71.8 305 484 134 82.7 28.41997 34.3 29.8 45.4 133 617 308 153 173 246 nd nd nd

Summary and Conclusions 27
28 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

Nutrient and sediment loading to Wonder Lake 

is strongly related to the hydrologic conditions of 

Nippersink Creek and the surrounding watershed. 

Suspended-sediment and nutrient loads were related 

to stream discharge. In years of greater streamflow, 

higher concentrations of nutrients and sediment 

were observed. Likewise, lower concentrations were 

observed in years when the mean annual flow was less 

than the average annual flow. Some of the dissolved 

forms of nitrogen were found in higher concentrations 

on a seasonal basis regardless of flow.

The median annual load of total phosphorus (during 1994-2001) in Nippersink Creek above Wonder 

Lake was 12.41 tons, whereas dissolved phosphorus 

was delivered at a median rate of 3.38 tons per year. 

The annual load of total organic nitrogen was 67.11 

tons. Median annual dissolved ammonia loading was 

5.7 tons. The median annual load of dissolved nitrate 

was 308.4 tons. 

It was not possible to reliably estimate the mean 

annual amounts of total and dissolved phosphorus 

trapped in Wonder Lake. The flow and concentrations 

were highly variable at Nippersink Creek below Wonder Lake during 1994-97. Between 6 and 28 percent 

of the total phosphorus load was trapped in the lake 

based on regression model analysis. A large portion 

of the load variability could not be explained by the 

regression.

Wonder Lake is characterized as eutrophic 

based on a trophic state index. Three criteria 

were used in evaluating the lake: Secchi disk 

depth, total phosphorus concentration, and chlorophyll a concentration. These criteria are indexed 

such that each measure is placed on similar scales 

for comparison. The lake was characterized 

nine times during 1999-2000 (total of 27 trophic 

state evaluations). Twenty-five of the 27 evaluations placed Wonder Lake in the eutrophic index 

category. Two measurements of chlorophyll a

concentration classified the lake as mesotrophic; 

however, the lake was classified as eutrophic 

based on the Secchi disk depth and total phosphorus concentration criteria.

The observed trapping efficiency of Wonder 

Lake is nearly 75 percent. As the lake fills with 

more sediment over time, this trapping efficiency 

will decrease. However, a decrease in the trapping efficiency usually is slow and gradual. If 

the lake were restored to its original capacity, 

the sediment-trapping efficiency likely would 

increase above the current rate. The data used in 

this calculation were collected during a period 

(1994-97) when the annual streamflow was less 

than the average flow for the period of record 

(1994-2001). The years of 1999 through 2001 

did not have sufficient data coverage to estimate a 

Table 8. Suspended-sediment and nutrient concentrations in Nippersink Creek below Wonder Lake, McHenry County, Ill., 1994-97. 

[All data except number of samples in milligrams per liter; MRL, method reporting level]

Statistic Daily mean suspended sediment Total Phosphorus 

as P

Dissolved Phosphorus 

as P

Number of Samples 1106 73 53

Mean 19.1 0.152 0.045

Minimum or

one-half MRL 3.1 .020 .005

10th-percentile 10.0 .060 .005

25th-percentile 14.0 .080 .020

Median 17.2 .120 .030

75th-percentile 22.1 .150 .040

90th-percentile 29.7 .204 .078

Maximum 90.2 1.81 .541

Standard Deviation 9.1 .215 .076

Variance 82.0 .046 .006

Skewness 2.1 6.80 5.64
Figure 18. Total and dissolved phosphorus (as P) concentrations in Nippersink Creek below Wonder Lake, McHenry County, Ill., July 1994 – July 1997.

Summary and Conclusions 29
30 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

Figure 19. Total phosphorus (as P) concentrations in Nippersink Creek below Wonder Lake, McHenry County, Ill., by A) month of sample 

and B) sampled flow.
Figure 20. Dissolved phosphorus (as P) concentrations in Nippersink Creek below Wonder Lake, McHenry County, Ill., by A) month of 

sample and B) sampled flow.

Summary and Conclusions 31
32 Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001

trapping efficiency. Loads of sediment delivered to 

the lake will decrease the volume, water clarity, and 

navigable areas of the lake.

About 15,900 tons of suspended sediment was 

transported in Nippersink Creek above Wonder 

Lake during the 1994-97 observation period. It is 

estimated that a similar amount of sediment was 

delivered to Wonder Lake in WY 2000 alone as had 

been delivered between June 1994 and June 1997. 

During all observations from 1994 to 2001 (1,990 

non-consecutive days), the estimated average daily 

sediment load was 25 tons. This daily loading indicates an average annual sediment load of 9,130 tons. 

If the 75-percent sediment-trapping rate applies in 

an average year, then about 6,800 tons of sediment 

is trapped within Wonder Lake in a typical year. If 

the lake could be restored to its original capacity, 

the sediment-trapping efficiency may be increased.

The water quality of lakes is affected greatly by 

their watershed. The amounts of water, sediment, 

and nutrients delivered to Wonder Lake through 

Nippersink Creek are affected by many natural 

processes and human factors, which are variable 

throughout time. The land uses in this study area 

have been changing over the last 30 years with 

increasing population and various agricultural practices, and these changes may affect future waterquality conditions in the lake. Estimating a typical 

condition, as well as simulating future conditions, 

may help watershed planners in addressing those 

variable conditions. 

SELECTED REFERENCES

Allan, J.D., 1995, Stream Ecology: Structure and 

function of running waters: Kluwer Academic 

Publishers, Dordrecht, The Netherlands, 388 p.

Table 9. Regression coefficients, significance level, and goodness-of-fit parameters, by calibration period, for nutrients in Nippersink 

Creek below Wonder Lake, McHenry County, Ill. 

[r2, explained variability;%, percent; S, standard error; >, greater than]

Nutrient

(Calibration Period)

Model Coefficient 

(p-value) r2

(%) S

β 0 β 1 β 2 β 3 β 4

Total Phosphorus 

(1994-97)

2.593 1.108 0 -0.183 -0.363

79.3 0.58

(0.000) (0.000) (>0.05) (0.139) (0.002)

Dissolved Phosphorus 

(1994-97)

1.119 1.004 0 0 0

49.3 1.04

(0.000) (0.000) (>0.05) (>0.05) (>0.05)

Table 10. Estimated annual total phosphorus retention in Wonder Lake, McHenry County, Ill., by model-calibration period. 

[%, percent; na, not applicable]

Total phosphorus model-calibration 

period and location

Load (tons), by Water Year (Oct. 1 – Sept. 30)

1996 1997 Mean Retained 

(%)

1999-2001 Above Wonder Lake 12.41 12.42 12.41 28.0

1994-97 Above Wonder Lake 10.41 8.54 9.48 5.8

1994-97 Below Wonder Lake 9.35 8.51 8.93 na
Arnold, T.L., Sullivan, D.J., Harris, M.A., Fitzpatrick, F.A., Scudder, B.C., Ruhl, P.M., Hanchar, 

D.W., and Stewart, J.S., 1999, Environmental setting of the upper Illinois River Basin and implications for water quality: U.S. Geological Survey 

Water-Resources Investigations Report 98-4268, 

67 p.

Brune, G.M., 1953, Trap Efficiency of Reser- voirs, in Melching, C.S., and Avery, C.C., 1990, 

An introduction to watershed management for 

hydrologists: [Belgium] Vrije Universiteit Brussel 

– Hydrologie, 18, 128 p.

Carlson, R.E., 1977, A trophic state index for lakes: 

Limnology and Oceanography, March, v. 22, 

no. 2, p. 361-369.

Cochran and Wilken, Inc., 1996, Wonder Lake Fea- sibility Study and Restoration Plan: prepared for 

the Master Property Owners Association of the 

Wonder Lake Area, 31 p. plus appendixes.

Cohn, T.A., 1988, Adjusted maximum likelihood 

estimation of the moments of lognormal popula- tions from Type I censored samples: U.S. Geo- logical Survey Open-File Report 88-350, 34 p.

Cohn, T.A., DeLong, L.L., Gilroy, E.J., Hirsch, 

R.M., and Wells, D.K., 1989, Estimating constituent loads: Water Resources Research, v. 25, no. 5, 

p. 937-942.

Cohn, T.A., Caulder, D.L., Gilroy, E.J., Zynjuk, 

L.D., and Summers, R.M., 1992a, The validity of 

a simple statistical model for estimating fluvial 

constituent loads; an empirical study involving 

nutrient loads entering Chesapeake Bay: Water 

Resources Research, v. 28, no. 9, p. 2353-2363.

Cohn, T.A., Gilroy, E.J., and Baier, W.G., 1992b, 

Estimating fluvial transport of trace constituents 

using a regression model with data subject to censoring: Proceedings of the Joint Statistical Meeting, Boston, Mass., August 9-13, 1992, 

p. 142-151.

Cole, G.A., 1994, Textbook of Limnology (4th ed.): 

Prospect Heights, Ill., Waveland Press, Inc., 

412 p.

Coupe, R.H., 1998, Concentrations and loads of 

nitrogen and phosphorus in the Yazoo River, 

northwestern Mississippi, 1996-97: U.S. Geological Survey Water-Resources Investigations Report 

98-4219, 17 p.

Edwards, T.K., and Glysson, G.D., 1988, Field 

methods for measurement of fluvial sediment: 

U.S. Geological Survey Open-File Report 86-531, 

118 p.

Field, S.J., Elder, J.F., Garn, H.S., Goddard, G.L., 

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Dupré and Robertson—Water Quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001—Scientific Investigations Report 2004-5085

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