U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2009–5237 

Prepared in cooperation with the Lake County Forest Preserve District and the 

Illinois State Geological Survey 

Hydrology, Water Quality, and Causes of Changes in 

Vegetation in the Vicinity of the Spring Bluff Nature Preserve, 

Lake County, Illinois, May 2007–August 2008 
Cover: Left–Staff gage on Dead Dog Creek at DD1 during normal water levels, May 28, 2007. (Photograph by Debbie Maurer, 

Lake County Forest Preserve District, Grayslake, Illinois.)

Right–Staff gage at Dead Dog Creek at DD1 during high water levels immediately after a spring precipitation event, 

May 31, 2008. (Photograph by Debbie Maurer, Lake County Forest Preserve District, Grayslake, Illinois.) 
Hydrology, Water Quality, and Causes of 

Changes in Vegetation in the Vicinity of the 

Spring Bluff Nature Preserve, Lake County, 

Illinois, May 2007–August 2008 

By Robert T. Kay, James J. Miner, Debbie A. Maurer, and Charles W. Knight 

Prepared in cooperation with the Lake County Forest Preserve District and the 

Illinois State Geological Survey 

Scientific Investigations Report 2009–5237 

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: 2010

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reproduce any copyrighted materials contained within this report.

Suggested citation:

Kay, R.T, Miner J.J., Maurer, D.A., and Knight, C.W., 2010, Hydrology, water quality, and causes of changes in vegetation in the vicinity of the Spring Bluff Nature Preserve, Lake County, Illinois, May 2007–August 2008: U.S. Geological 

Survey Scientific Investigations Report 2009–5237, 73 p. 
iii

Contents

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

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

Purpose and Scope ..............................................................................................................................6

Description of the Study Area ............................................................................................................6

Watersheds and Land Use .........................................................................................................6

Kellogg Creek and Dead Dog Creek ..............................................................................11

Bull Creek and Dead River ..............................................................................................11

Meteorological Data .................................................................................................................13

Topography .................................................................................................................................14

Methods of Investigation...................................................................................................................17

Water-Level Measurement ......................................................................................................17

Surveying............................................................................................................................17

Surface-Water Discharge...............................................................................................17

Water-Quality Sampling ..................................................................................................19

Vegetation Monitoring .....................................................................................................20

Surface-Water Hydrology ..........................................................................................................................20

Water Levels Through Time ..............................................................................................................20

Direction and Timing of Surface-Water Flow.................................................................................25

Hydroperiod ................................................................................................................................29

Surface-Water Discharge .......................................................................................................31

Implications of Surface-Water Hydrology......................................................................................32

Groundwater Hydrology..............................................................................................................................32

Groundwater Levels Through Time..................................................................................................33

Hydroperiods Associated With Different Plant Communities .....................................................34

Relation of Hydroperiod to Invasive Plant Species.......................................................................35

Surface-Water Quality ................................................................................................................................38

Field Parameters ................................................................................................................................38

Temperature................................................................................................................................38

Dissolved Oxygen.......................................................................................................................41

pH..................................................................................................................................................41

Specific Conductance...............................................................................................................41

Turbidity .......................................................................................................................................42

Chloride.................................................................................................................................................44

Nitrogen and Phosphorous ..............................................................................................................47

Suspended Sediment .........................................................................................................................50

Apparent Attenuation of Suspended Sediment, Chloride, Dissolved Phosphorous, and 

Nitrate Within the Wetland Complex .................................................................................53

Relation of Hydrology and Water Quality to Invasive Species.............................................................54

Summary and Conclusions.........................................................................................................................58

References Cited..........................................................................................................................................59

Glossary.........................................................................................................................................................63

Appendix 1. Water-level measurements in the vicinity of Spring Bluff Nature Preserve, 

Lake County, Illinois..........................................................................................................65
iv

Figures

1–7. Maps showing:

1. Location of Spring Bluff Nature Preserve, Chiwaukee Prairie State 

Natural Area, Illinois Beach State Park, and selected site features, 

near Winthrop Harbor and Waukegan, Ill. ......................................................................2

2. Location of selected surface-water bodies and monitoring points in the 

vicinity of the Spring Bluff Nature Preserve, Chiwaukee Prairie State 

Natural Area, and Illinois Beach State Park, near Winthrop Harbor and 

Waukegan, Ill........................................................................................................................7

3. Location of selected features in the vicinity of the Spring Bluff Nature 

Preserve, Winthrop Harbor, Ill...........................................................................................8

4. Location of selected features in the vicinity of the Southern Unit of the 

Illinois Beach State Park near Waukegan, Ill. ................................................................9

5. Land cover in the watersheds for Kellogg Creek, Dead Dog Creek, 

Bull Creek, and the Dead River, northeastern Lake County, Ill...................................10

6. Topography in the vicinity of the Spring Bluff Nature Preserve, 

Winthrop Harbor, Ill. ..........................................................................................................15

7. Topography in the vicinity of the Southern Unit of the Illinois Beach 

State Park near Waukegan, Ill.........................................................................................16

8–12. Graphs showing:

8. Water levels in Dead Dog Creek at gage DD1, May 25, 2007–June 11, 2008, 

in the vicinity of the Spring Bluff Nature Preserve, Winthrop Harbor, Ill. ................21

9. Water levels at gage W1, May 24, 2007–June 11, 2008, in the vicinity of 

the Spring Bluff Nature Preserve, Winthrop Harbor, Ill. .............................................21

10. Precipitation measured at the National Oceanic and Atmospheric 

Administration Station, Kenosha, Wis., May 1, 2007–June 30, 2008 .........................22

11. Water levels at gage DD1 in the vicinity of the Spring Bluff Nature 

Preserve, Winthrop Harbor, Ill., June 24 and 25, 2007 .................................................23

12. Water levels in the Dead River at gage DR3 in the Southern Unit of the 

Illinois Beach State Park, near Waukegan, Ill., May 24, 2007–June 11, 2008..........24

13–14. Maps showing:

13. Surface-water levels and flow directions in the vicinity of the Southern Unit 

of the Illinois Beach State Park, near Waukegan, Ill., April 29, 2008 ........................26

14. Surface-water levels, specific conductance, and flow directions in the 

vicinity of the Spring Bluff Nature Preserve, Chiwaukee Prairie State 

Natural Area, and Northern Unit of the Illinois Beach State Park, near 

Winthrop Harbor, Ill., April 29, 2008.................................................................................27

15–20. Graphs showing:

15. Hydrograph showing water-level responses to June 8, 2008, rainfall, 

Spring Bluff Nature Preserve, Winthrop Harbor, Ill. ....................................................29

16. Depth to groundwater in monitoring wells, Spring Bluff Nature Preserve, 

Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, near 

Winthrop Harbor and Waukegan, Ill., July 2007–August 2008 ...................................33

17. Average depth to groundwater in each type of wetland community, 

Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and 

Illinois Beach State Park, near Winthrop Harbor and Waukegan, Ill., 

July 2007–August 2008......................................................................................................34
v

18. Surface-water temperatures recorded at well locations in the vicinity 

of the Spring Bluff Nature Preserve, Winthrop Harbor, Ill., 

September 2007–June 2008 .............................................................................................41

19. Specific conductance of surface water and amount of precipitation at 

selected gages and well locations in the vicinity of the Spring Bluff Nature 

Preserve, Winthrop Harbor, Ill., July 2007–July 2008...................................................43

20. Turbidity and precipitation in Dead Dog Creek and wetlands in the vicinity 

of the Spring Bluff Nature Preserve, Winthrop Harbor, Ill., 

October 2007–July 2008 ....................................................................................................43

21–22. Maps showing:

21. Concentrations of chloride and dissolved nitrate plus nitrite as nitrogen in 

surface water in the vicinity of the Spring Bluff Nature Preserve, Chiwaukee 

Prairie State Natural Area, and Northern and Southern Units of the Illinois 

Beach State Park near Winthrop Harbor and Waukegan, Ill., May 13, 2008...........46

22. Concentrations of dissolved phosphorous in surface water in the vicinity 

of the Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, 

and Northern and Southern Units of the Illinois Beach State Park near 

Winthrop Harbor and Waukegan, Ill., April 2, 2008 ......................................................49

23–29. Graphs showing:

23. Water-level elevation and concentration of suspended sediment in 

Dead Dog Creek at gage DD1, Spring Bluff Nature Preserve, Winthrop 

Harbor, Ill., March 26–April 2, 2008 .................................................................................51

24. Concentration of suspended sediment in the Spring Bluff Nature Preserve, 

Northern Unit Illinois Beach State Park, and Chiwaukee Prairie State 

Natural Area, near Winthrop Harbor and Waukegan, Ill., March 26–

April 2, 2008.........................................................................................................................52

25. Concentration of suspended sediment in Bull Creek at gage DR1 and 

water level of Dead Dog Creek at gage DD1, near Winthrop Harbor and 

Waukegan, Ill., April 10–13, 2008.....................................................................................53

26. Relation of Typha spp. importance value to days of inundation at vegetationmonitoring points in the Spring Bluff Nature Preserve, Northern Unit Illinois 

Beach State Park, and Chiwaukee Prairie State Natural Area, near Winthrop 

Harbor and Waukegan, Ill., July 24, 2007–August 27, 2008.........................................56

27. Relation of Typha spp. importance values to average depth to groundwater 

at vegetation-monitoring points in the vicinity of the Spring Bluff Nature 

Preserve, Northern Unit Illinois Beach State Park, and Chiwaukee Prairie 

State Natural Area, near Winthrop Harbor and Waukegan, Ill., July 24–

August 27, 2008...................................................................................................................56

28. Relation of species richness index (SRI) values to average depth to 

groundwater at monitoring-well locations in the Spring Bluff Nature 

Preserve, Northern Unit Illinois Beach State Park, and Chiwaukee Prairie 

State Natural Area, near Winthrop Harbor and Waukegan, Ill..................................57

29. Relation of Typha spp. importance values to specific conductance of 

surface water in the Spring Bluff Nature Preserve, Northern Unit Illinois 

Beach State Park, and Chiwaukee Prairie State Natural Area, near 

Winthrop Harbor and Waukegan, Ill...............................................................................57 
vi

Tables

1a. Federal and State listed animal species identified within the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, 

near Winthrop Harbor and Waukegan, Ill. ...............................................................................3

1b. Federal and State listed plant species identified within the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, 

near Winthrop Harbor and Waukegan, Ill. ...............................................................................4

2. Change in vegetation sampled from 1997 to 2005–06 along permanent transects 

in Spring Bluff Nature Preserve, Winthrop Harbor, Ill............................................................5

3. Gage locations and well locations with associated plant community information 

in the vicinity of the Spring Bluff Nature Preserve, Chiwaukee Prairie State 

Natural Area, and Illinois Beach State Park, near Winthrop Harbor and 

Waukegan, Ill...............................................................................................................................12

4. Climate data, May 2007–August 2008, Kenosha, Wis...........................................................14

5. Information on gages and wells in the vicinity of the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, 

near Winthrop Harbor and Waukegan, Ill. .............................................................................18

6. Estimated evapotranspiration rates at selected gages in the vicinity of the 

Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and 

Illinois Beach State Park, near Winthrop Harbor and Waukegan, Ill. ...............................24

7. Summary of water levels at gages in the vicinity of the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, 

near Winthrop Harbor and Waukegan, Ill., May 24, 2007–June 11, 2008 ..........................25

8. Hydroperiod, in days, at selected gages in the wetlands in the vicinity of the 

Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and Illinois 

Beach State Park, near Winthrop Harbor and Waukegan, Ill., May 24, 2007–

May 24, 2008 ................................................................................................................................30

9. Streamflow measurements at selected gages in the vicinity of the Spring Bluff 

Nature Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach 

State Park, near Winthrop Harbor and Waukegan, Ill., May 24, 2007–May 13, 2008 ......31

10. Characteristics of vegetation, hydrology, and specific conductance sampled, 

including summaries by plant community, adjacent to wells 1–22 at the Spring 

Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach 

State Park, near Winthrop Harbor and Waukegan, Ill..........................................................35

11. Field-parameter measurements in surface water at gages in the vicinity of 

the Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and 

Illinois Beach State Park, near Winthrop Harbor and Waukegan, Ill., 

May 31, 2007–May 13, 2008 .......................................................................................................39

12. Concentrations of laboratory-determined constituents in surface water at 

gages in the vicinity of the Spring Bluff Nature Preserve, Chiwaukee Prairie 

State Natural Area, and Illinois Beach State Park, near Winthrop Harbor and 

Waukegan, Ill., May 31, 2007–May 13, 2008............................................................................44

13. Pearson correlations and two-tailed p-values for selected parameters in the 

vicinity of the Spring Bluff Nature Preserve, Winthrop Harbor, Ill., July 24, 2007–

July 7, 2008...................................................................................................................................55

1–1. Water-level elevation at gages and in wells in the vicinity of Spring Bluff Nature 

Preserve, Lake County, Ill. .........................................................................................................66
vii

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 0.4047 hectare (ha)

square foot (ft2

) 0.09290 square meter (m2)

square inch (in2

) 6.452 square centimeter (cm2)

square mile (mi2

) 2.590 square kilometer (km2)

Flow rate

cubic foot per second (ft3

/s) 28.32 cubic decimeter per second 

(dm3

/s)

Evapotranspiration rate

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

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

°F=(1.8×°C)+32 

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

(NAVD 88). 

Elevation, as used in this report, refers to distance above or below NAVD 88.

Horizontal coordinate information used in this report is the North American Datum of 1983 

(NAD 83).

Abbreviated water-quality units used in this report: Constituent concentrations are given in 

milligrams per liter (mg/L). Milligrams per liter are considered equivalent to parts per million at 

the reported concentrations. 

Turbidity measured according to U.S. Environmental Protection Agency approved GLI method 

2 is given in Formazin nephelometric units (FNU) and are equivalent to nephelometric turbidity 

units.

Specific conductance is given in microsiemens per centimeter (μS/cm). 

Conversion Factors, Vertical Datum, Abbreviated WaterQuality Units, and Other Abbreviations

1–2. Depth to water at gages and in wells in the vicinity of Spring Bluff Nature 

Preserve, Lake County, Ill. .........................................................................................................69

1–3. Water-level elevation at gages and in wells in the vicinity of Spring Bluff Nature 

Preserve, Lake County, Ill. .........................................................................................................72
viii

Other abbreviations used in this report 

CDT Central Daylight Time

CPSNA Chiwaukee Prairie State Natural Area

GIS Geographic Information System

IBSP Illinois Beach State Park and Nature Preserve

IPCB Illinois Pollution Control Board

ISGS Illinois State Geological Survey

LCFPD Lake County Forest Preserve District

LCSMC Lake County Stormwater Management Commission

NLCD National Land Cover Database

NUIBSP Northern Unit Illinois Beach State Park

SBNP Spring Bluff Nature Preserve

SRI Species Richness Index

SUIBSP Southern Unit Illinois Beach State Park

USGS U.S. Geological Survey
Hydrology, Water Quality, and Causes of Changes in 

Vegetation in the Vicinity of the Spring Bluff Forest 

Preserve, Lake County, Illinois, May 2007–August 2008 

By Robert T. Kay, James J. Miner, Debbie A. Maurer, and Charles W. Knight 

Abstract

Agriculture and urbanization have altered the hydrology 

and water quality of the coastal wetland complex along the 

shore of Lake Michigan at the Spring Bluff Nature Preserve 

and Illinois Beach State Park in northeastern Lake County, 

Ill., and the adjacent Chiwaukee Prairie State Natural Area in 

southeastern Wisconsin. Culverts, roads, ditches, and berms 

installed within the wetland complex have altered the natural 

directions of surface-water flow and likely have increased 

the natural hydroperiod in the Spring Bluff Nature Preserve 

and decreased it in the northern part of the Illinois Beach 

State Park. Relative to presettlement conditions, surfacewater runoff into the wetlands likely is greater in quantity 

and higher in concentrations of several constituents, including chloride, nitrate, phosphorous, and suspended sediment. 

These constituent concentrations are affected by a variety of 

factors, including the amount of agricultural and urban land 

use in the watersheds. Hydrologic, chemical, and biologic 

processes within the wetland communities reduce the concentrations of these constituents in surface water before the water 

discharges to Lake Michigan by as much as 75 percent for 

chloride, 85 percent for nitrate, 66 percent for phosphorous, 

and more than an order of magnitude for suspended sediment. 

However, concentrations of phosphorous and suspended sediment in surface water increased within parts of the wetland 

complex. Given these changes, the floristic quality of these 

wetlands has been altered from the historic condition. Specifically, Typha spp. and Phragmites australis occur in greater 

numbers and over a larger area than in the past. The spread of 

Typha spp. and Phragmites australis appears to be enhanced 

by anthropogenic alterations within the wetland complex, such 

as increased water levels and duration of inundation and, possibly, increases in the total concentration of dissolved constituents in water. 

Introduction

Wetlands perform many functions, including improvement of water quality and providing habitat for plant and 

animal species (Mitsch and Gosselink, 2007). However, the 

hydrology, water quality, and biological communities in many 

wetlands, including coastal wetlands bordering large areas 

of the Great Lakes, have been affected by agriculture and 

urban land-use practices in the wetlands and their watersheds 

(Geis, 1985; McCullough, 1985; Maynard and Wilcox, 1997; 

Werner, 2001; Werner and Zedler, 2002; Thrush and others, 

2004). Degradation of habitat and reduction in biodiversity 

within coastal wetlands associated with changes in hydrology, in addition to chemical and sediment loading associated 

with agricultural and urban land uses, are of concern to land 

managers throughout the Great Lakes region. The ability of 

coastal wetlands to reduce sediment and chemical fluxes via 

surface water into the lakes also is of interest to those trying to 

protect the lakes.

The Zion Beach-Ridge Plain, located adjacent to Lake 

Michigan in southeast Wisconsin and northeast Illinois, 

supports extensive coastal wetland communities and upland 

habitat. The plain, formed by the deposition and migration of 

a succession of nearly parallel beach ridges, extends approximately 18 mi north to south from Kenosha Dunes in Wisconsin to Waukegan Harbor in Illinois and has a maximum width 

of about 1 mi (Chrzastowski, 2001). The part of the beachridge plain within the scope of this study, referred to as the 

coastal complex, includes the southern part of the Chiwaukee 

Prairie State Natural Area (CPSNA), the Spring Bluff Nature 

Preserve (SBNP), and the Illinois Beach State Park and Nature 

Preserve (IBSP), which are owned and actively managed by 

public and not-for-profit agencies (fig. 1). 
2 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Figure 1. Location of Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, Illinois Beach State Park, 

and selected site features, near Winthrop Harbor and Waukegan, Illinois. 

WISCONSIN

ILLINOIS

Kenosha County

Lake County

87°50' 87°48' 87°46'

42°24'

42°26'

42°28'

0 1 2 MILES

0 1 2 KILOMETERS

Kellogg

Creek

Dead

Dog Cr.

7th Street

Bull

Dead River

North

Point

Marina

Cr

Spring Bluff

Nature Preserve

Lake Michigan

Base derived from U.S. Geological Survey High-Resolution

Orthoimagery for the Chicago, Ill. urban area, 2005.

ILLINOIS Lake County

Chicago

EXPLANATION

Lake or pond

Marsh

Stream

Illinois Beach State Park boundary

Southern Unit

Illinois Beach

State Park

Northern Unit

Illinois Beach

State Park

Chiwaukee Prairie

State Natural Area

WISCONSIN Kenosha County

Dead Dog Cr.

Winthrop Harbor

Zion

Waukegan
Introduction 3

The wetlands within this area represent the vast majority of comparatively undisturbed wetlands remaining along 

Lake Michigan in Illinois and southeast Wisconsin (Chrzastowksi, 2007). Combined, the coastal complex comprises over 

4,000 acres of hydrologically linked wetland communities, 

including high-quality sedge meadows1, panne, fens, wet 

prairies, and emergent marsh habitat, as well as a mosaic 

of upland communities, including sand savanna, dry, mesic, 

and wet-mesic sand prairie. IBSP also preserves 6.5 mi of 

Lake Michigan coastline, including beach and foredune communities. Industry and the construction of residences, roadways, drainage ditches, and recreational areas in and near parts 

of the wetland complex have altered the natural landscape and 

appear to have resulted in the degradation of some vegetation communities. However, the coastal complex continues to 

support numerous state and federally listed species (table 1), 

as well as remnant high-quality plant communities. In addition, the coastal complex is an important buffer between Lake 

Michigan and the largely agricultural and urban landscape to 

the west. 

1

 Terms included in the glossary are in bold type at their first use in the text.

Typha angustifolia and T. latifolia were described as present, and in some locations dominant, in the coastal complex as 

early as 1912 (Gates, 1912). During the last several decades, 

land managers at SBNP have documented an increase in 

abundance and area of Typha spp. (term describing the cattail 

genus, which in this area consist of the species Typha angustifolia or narrow leaf cattail, T. latifolia or broad leaf cattail, 

and T. × glauca or cattail hybrids) and Phragmites australis

(common reed) within the preserve. This increase has reduced 

the floristic quality of the wetlands and altered wildlife habitat structure and forage. For example, in a span of less than 

10 years, permanent vegetation transects sampled at SBNP 

showed an increase in importance value of Typha spp. across 

all transects; in the most extreme case, native species floristic 

quality decreased from 73.98 to 14.15 (Lake County Forest 

Preserve District, written commun., 2008; table 2). 

Table 1a. Federal and State listed animal species identified within the Spring 

Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach 

State Park, near Winthrop Harbor and Waukegan, Illinois (from surveys by the Lake 

County Forest Preserve District). 

[ST, State threatened; SE, State endangered; FE, Federally endangered] 

Common name Scientific name Illinois 

status

Wisconsin 

status

Redveined leafhopper Aflexia rubranura ST SE

Henslow’s sparrow Ammodramus henslowii SE

Upland sandpiper Bartramia longicauda SE

Veery Catharus fuscescens ST

Longnose sucker Catostomus catostomus ST

Piping plover Charadrius melodus SE

Kirtland’s watersnake Clonophis kirtlandii SE

Cisco Coregonus artedii ST

Lake whitefish Coregonus clupeaformis ST

Blanding’s turtle Emydoidea blandingii ST

Brewer’s blackbird Euphagus cyanocephalus ST

Hoary elfin Incisalia polios SE

Least bittern Ixobrychus exilis SE

Richardsons rush Juncus alpinoarticulatus SE

Karner blue butterfly Lycaeides melissa samuelis SE, FE

Black-crowned night-heron Nycticorax nycticorax SE

Silphium borer moth Papaipema silphii SE

Leafhopper Paraphlepsius lupalus SE

Pied-billed grebe Podilymbus podiceps SE

King rail Rallus elegans SE
4 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Table 1b. Federal and State listed plant species identified within the Spring Bluff 

Nature Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, 

near Winthrop Harbor and Waukegan, Illinois (from surveys by the Lake County Forest 

Preserve District). 

[ST, State threatened; SE, State endangered; FT, Federally threatened] 

Common name Scientific name Illinois 

status

Wisconsin 

status

Round stem foxglove Agalinis gattingeri ST

Pale false foxglove Agalinis skinneriana ST SE

Marram (beach) grass Ammophila breviligulata SE

Bearberry Arctostaphylos uva-ursi SE

Prairie milkweed Asclepias sullivantii ST

Forked aster Aster furcatus ST

Prairie indian plantain Cacalia tuberosa ST

American sea-rocket Cakile edentula ST

Grass-pink orchid Calopogon tuberosus SE

Golden sedge Carex aurea SE

Elk sedge Carex garberi SE

Little green sedge Carex viridula ST

Downey yellow-painted cup Castilleja sessiliflora SE

Redroot Ceanothus ovatus SE

Seaside spurge Chamaesyce poligonifolia SE

Pitcher’s thistle Cirsium pitcheri ST, FT

Small yellow lady's-slipper Cypripedium parviflorum ST

Roundleaf sundew Drosera rotundifolia SE

Capitate spikerush Eleocharis olivacea SE

Bearded wheat grass Elymus trachycaulus SE

Hairy fimbristylis Fimbristylis puberlua SE

Yellow gentian Gentiana alba ST

Kalm’s St. John’s wort Hypericum kalmianum SE

Richardsons rush Juncus alpinoarticulatus SE

Ground juniper Juniperus communis ST

Trailing juniper Juniperus horizontalis SE

Pinweed Lechea intermedia ST

Clustered broomrape Orobanche fasciculata SE

Smooth phlox Phlox glaberrima ssp. interior SE

Jack pine Pinus banksiana SE

Wood orchid Platanthera clavellata SE

Tubercled orchid Platanthera flava var. herbiola SE

Eastern prairie fringed orchid Platanthera leucophaea SE, FT SE, FT

Purple-fringed orchid Platanthera psycodes SE

Pink milkwort Polygala incarnata SE

Balsam poplar Populus balsamifera SE

Beaked rush Rhynchospora alba ST

Dune willow Salix syrticola SE

Reddish bulrush Scirpus microcarpus SE

Sticky false asphodel Tofieldia glutinosa ST ST

Seaside arrow-grass Triglochin maritima ST

Bog arrow-grass Triglochin palustre ST

Horned bladderwort Utricularia cornuta SE

Flat-leaved bladderwort Utricularia intermedia SE

Small bladderwort Utricularia minor SE

Marsh speedwell Veronica scutellata ST
Introduction 5

One vegetation transect in the northeast part of SBNP lost 

15 ft of diverse mesic prairie to complete dominance by 

Typha spp. from 1997 to 2006. Anecdotal accounts from local 

residents indicate that, 40 to 50 years ago, areas in the SBNP 

that are now dominated by Typha spp. and have standing water 

for much of the year contained non-Typha spp. vegetation that 

reached only knee height and rarely contained standing water 

(Robert Martinelli, resident of Winthrop Harbor, oral commun., 2008). Residents also stated that there were only three 

specific locations where Typha spp. grew 45 year ago. These 

accounts are corroborated by the authors, who have identified 

dead sedge tussocks submerged beneath 4 to 6 in. of water or 

in areas dominated by Typha spp., indicating a shift in plantcommunity type from assemblages adapted to lower water 

levels to assemblages adapted to higher water levels. Lake 

County Forest Preserve District (LCFPD) land managers also 

have noted that water levels in the wetlands at the SBNP have 

been higher for longer periods of time than would be expected 

for the plant communities that are in the wetlands during at 

least the past 10 years, and that these higher water levels seem 

to have been accompanied by an expansion of Typha spp. into 

a larger part of the SBNP, with an accompanying decrease in 

the diversity of the wetland plant communities. An increase in 

Typha spp. and Phragmites australis also has been observed 

in recent years along the banks of the Dead River (fig. 1) and 

adjacent wetland swales in the IBSP (Deborah Nelson, Illinois 

Department of Natural Resources, oral commun., 2007). 

The spread of invasive plant species often is correlated 

with the alteration of native communities and is the focus of 

land-management practices such as chemical and biologic 

control (Randall, 1996). The factors that facilitate the spread 

of invasive species are less well understood by land managers and often are not addressed or are occurring in geographic 

areas outside their jurisdiction. Changes in hydroperiod and 

water quality within wetlands have been linked to an increase 

in rate of spread and abundance of invasive plant species, 

such as Typha angustifolia, T. × glauca, and Phragmites 

australis (Spuhler, 1994; Panno and others, 1999; Woo and 

Zedler, 2002). Typha spp. abundances are strongly correlated 

with higher water levels and total days of inundation (Tarr 

and Babbitt, 2006). The spread of invasive wetland plants 

within the SBNP, and thus the reduction of the diversity of the 

native flora and change in habitat, may be related to changes 

in the hydrology and water quality. These changes are primarily increased volume and rate of surface-water flow into the 

wetland complex; hydrologic alterations within the wetlands 

related to the construction of roads, ditches, and culverts; and 

increased chloride, nutrient, and sediment inputs from agricultural and urban land in the watersheds (Mueller and Helsel, 

1996; Hamilton and others, 2001).

Invasive species may out compete native species across a 

spectrum of hydrologic regimes (Kercher and Zedler, 2004a), 

including Tyhpa spp. in increasingly wet environments such as 

emergent marshes (Tarr and Babbitt, 2006). However, research 

also has shown at least some Typha spp. to be adversely 

affected by periodic drought. Li and others (2004) found that 

periodic drought reduced photosynthesis, stomatal conductance, and leaf chlorophyll content in T. latifolia, as well as 

contributing to biomass reduction and substantial reductions 

in root growth compared to shoot growth. If these findings are 

true for the Typha spp. present in the wetland complex, then 

decreased wetness could reduce Typha spp. viability. Other 

research has shown that Typha spp. responds favorably to 

decreased soil redox values (Kludze and DeLaune, 1996), as 

well as stability of water levels (Boers and Zedler, 2008), both 

of which would occur given long-term increases in saturation 

related to hydrologic alterations in the wetland complex. 

In addition to assessing the effects of urban and agricultural land use on the biotic integrity of the coastal wetlands, 

assessing the effects of coastal wetlands on mitigating the 

impact of urban and agricultural land-use practices on the 

eutrophication of the Great Lakes is of concern. The presence of nutrients such as phosphorous and nitrogen in water 

and sediments entering the Great Lakes has the potential to 

increase the algal productivity of the lakes, which can lead 

to decreased concentrations of dissolved oxygen in the lake 

water and other adverse impacts. Coastal wetlands can remove 

nutrients and sediments from surface water entering the Great 

Lakes (Heath, 1992; Coon and others, 2000), so the loss of 

these wetlands, or degradation of their ability to function, may 

have adverse consequences to the ecological integrity of the 

Great Lakes.

Table 2. Change in vegetation sampled from 1997 to 2005–06 along permanent transects in Spring Bluff Nature Preserve, 

Winthrop Harbor, Illinois. Locations of transects are shown in figures 2–4. 

[Data from Lake County Forest Preserve District, written commun., 2008] 

Permanent 

transect 

location

Relative importance 

value of 

Typha spp.

Relative importance 

value of 

Phragmites australis

Relative importance 

of bare ground/

open water

Native species 

richness index 

(square root)

Mean 

vegetation 

wetness 

1997 2005–06 1997 2005–06 1997 2005–06 1997 2005–06 1997 2005–06

T4 5.2 15.5 1.5 1.7 20.9 10.1 51.1 46.2 -3.9 -3.9

T5 26.9 17.3 .0 9.3 23.1 20.4 16.1 19.6 -4.4 -4.3

T6 7.0 32.1 .0 .0 28.5 33.1 25.2 5.5 -3.1 -3.9

T8 .0 16.5 .0 .0 20.7 42.6 74.0 11.7 1.6 -3.0
6 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

If not understood, the factors that facilitate the establishment and spread of invasive plants may impede attainment 

of the long-term conservation goals for coastal wetlands. A 

comparison of the water quality entering the wetland complex 

and exiting to Lake Michigan can be used to quantify the role 

of the wetlands on reducing chemical and sediment loads to 

the lake. This information may be used to support policies 

that facilitate improvement of biology and water quality of the 

wetland complex and the Great Lakes.

To support these objectives, this investigation was done 

by the U.S. Geological Survey (USGS) Illinois Water Science Center, Illinois State Geological Survey (ISGS), and 

the LCFPD. The investigation was done to document current 

(May 2007–August 2008) hydrologic, chemical, and biologic 

conditions; assess spatial patterns in these conditions; and 

identify causes of changes in conditions to aid resource managers in conservation planning and future restoration work. 

The investigation assessed the effects of agricultural and urban 

runoff, as well as physical alterations to the wetland complex, 

on the hydrology and water quality of the coastal wetland 

complex; the effect of the coastal wetland complex on improving water quality entering Lake Michigan; and the effect of 

changes in hydrology and water quality in the wetland complex on selected current plant-community patterns. 

Purpose and Scope

This report summarizes floristic quality, surface-water 

and groundwater hydrology, and surface-water quality associated with the Kellogg/Dead Dog Creek2

 and Bull Creek/Dead 

River Watersheds in the coastal wetland complex adjacent to 

Lake Michigan in northeastern Lake County, Ill., and southeastern Wisconsin. Data collection focused on the SBNP but 

also included the southern part of the CPSNA and parts of 

the IBSP. Data were collected from May 2007–August 2008. 

The report describes baseline surface-water and groundwater 

hydrology and water quality and the hydroperiod of the various wetland types. The report also quantifies types of plants 

within the various plant communities, identifies patterns of floristic quality and invasive plant dominance across a variety of 

community types, assesses the effects of the wetland complex 

on mitigating chemical and sediment loads into Lake Michigan, and identifies the possible causes, extent, and effects of 

altered hydroperiods and surface-water quality on wetland 

floristic quality. 

2

 “Dead Dog Creek” is local nomenclature, not currently (2010) recognized 

by the U.S. Board on Geographic Names.

Description of the Study Area

The study area is divided into the northern part and the 

southern part. The northern part of the study area consists of 

the SBNP, the northern part of the Northern Unit of the IBSP 

(NUIBSP), and the southern part of the CPSNA (fig. 2). The 

northern part of the study area is the area within the polygon 

defined by well 15 to the north, surface-water measuring 

points (hereafter known as gages) DD3 and DD4 to the south, 

Lake Michigan to the east, and gage DD1 to the west (fig. 3). 

The southern part of the study area consists largely of the area 

surrounding the Dead River and Bull Creek in the vicinity of 

the Southern Unit of the IBSP (SUIBSP) and is the area within 

the polygon defined by gage DR1 to the north and west and 

the outlet of the Dead River to Lake Michigan near gage DR3 

to the south and east (figs. 2 and 4).

Watersheds and Land Use

The Lake County Stormwater Management Commission 

(LCSMC) identifies two major watersheds in northeastern 

Lake County: Kellogg Creek and the Dead River (fig. 5). For 

management purposes, the LCSMC includes Dead Dog Creek 

as a subwatershed within the Kellogg Creek Watershed; however, they are hydraulically distinct. 

The land-cover statistics for the study area were derived 

for this investigation by manipulation of the 2001 Multi-Resolution Land Characteristics Consortium National Land Cover 

Database (NLCD). Land cover in this area was composed of 

15 separate categories that were combined into urban, agricultural, and natural. The statistics for the Dead River and Kellogg Creek Watersheds were obtained by creating a mask with 

the watershed polygons and selecting out those areas from the 

NLCD. All the 100-ft by 100-ft cells were added to determine 

the total area per category and then divided by the total area of 

the polygon to get the percent land cover by category for the 

watersheds. 
Introduction 7

WISCONSIN

ILLINOIS

Kenosha County

Lake County

87°50' 87°48' 87°46'

42°24'

42°26'

42°28'

0 1 2 MILES

0 1 2 KILOMETERS

Kellogg

Creek

Dead

Dog Cr.

7th Street

Bull

Dead River

North

Point Marina

Cr

Spring Bluff

Nature Preserve

Lake Michigan

Base derived from U.S. Geological Survey High-Resolution

Orthoimagery for the Chicago, Ill. urban area, 2005.

EXPLANATION

Lake or pond

Marsh

Stream

Illinois Beach State Park boundary

Surface-water measuring point

and identifier

Illinois State Geological Survey

gages (A-H) and wells (1-22)

Southern Unit

Illinois Beach

State Park

Northern Unit

Illinois Beach

State Park

Dead Dog Cr. SG1 DD1

DD2

DD4 DD3

W3

W4

W2

W1

DR1

DR2

DR3

W1

Chiwaukee Prairie

State Natural Area

19

18 16 17 15 14

13 G H

12

11

10

6 8 9 7

F

E D

1

1

5

4

3 2

C B

20 A

21 22

Winthrop Harbor

Zion

Waukegan

Figure 2. Location of selected surface-water bodies and monitoring points in the vicinity of the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, near Winthrop Harbor and Waukegan, 

Illinois. 
8 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008 B L U F F

DD1 DD2

DD4

DD3

W3

W4

W2

W1

Dead Dog Creek

Dead

k

D

e o e g r C

North

Point

Marina

Spring Bluff

Nature Preserve

Lake Michigan

Base derived from U.S. Geological Survey High-Resolution

Orthoimagery for the Chicago, Ill. urban area, 2005.

Chiwaukee Prairie

State Natural Area

Northern Unit

Illinois Beach State Park

Access road

Access road

Access road

Access road

7th Street

WISCONSIN

ILLINOIS

O dl rail spur

18

14 15 16 17

13 G H

1

5 4

2 3 C

B

SG1

87°49' 87°48'30" 87°48'

42°29'30"

42°29'

0 0.25 0.5 MILE

0 0.25 0.5 KILOMETER

12

11

10 9

8

6 7

F

D E 4

6

8

5

Access road

Open water

Stream

Railroad track

Illinois Beach State Park boundary

W1 Surface-water measuring point and identifier

Culvert

Storm drain

1

EXPLANATION

Vegetation transect and identifier

Illinois State Geological Survey gage (B-H) or well (1-18) 4

Figure 3. Location of selected features in the vicinity of the Spring Bluff Nature Preserve, Winthrop 

Harbor, Illinois. 
Introduction 9

B L U F F

DR1

DR2

DR3

Bull

Dead River

Creek

Lake

Michigan

87°50' 87°49'30" 87°49' 87°48'30" 87°48'

42°25'30"

42°25'

42°24'30"

0 0.25 0.5 MILE

0 0.25 KILOMETER 0.5

Base derived from U.S. Geological Survey High-Resolution

Orthoimagery for the Chicago, Ill. urban area, 2005.

Southern Unit

Illinois Beach State Park

20 22

A 21

DR1

EXPLANATION

Open water

Stream

Railroad tracks

Surface-water measuring point and identifier

Culvert

Illinois Beach State Park boundary

20 Illinois State Geological Survey gage (A) and well (20-22)

Figure 4. Location of selected features in the vicinity of the Southern Unit of the Illinois Beach State Park near 

Waukegan, Illinois. 
10 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Figure 5. Land cover in the watersheds for Kellogg Creek, Dead Dog Creek, Bull Creek, and the Dead River, 

northeastern Lake County, Illinois. 

87°52' 87°50' 87°48' 87°46'

42°24'

42°26'

42°28'

42°30'

0 1 MILE

0 1 KILOMETER

Kellogg Creek

Dead Dog Cr.

Bull

Dead River

North

Point

Marina

Spring Bluff

Nature Preserve

Lake Michigan

Base derived from Illinois Natural History Survey's 1999-2000

1:100,000-Scale Illinois Gap Analysis Land Cover Classification,

Raster Digital Data, Version 2.0, September 2003.

EXPLANATION

LAND COVER

A

Rural rassland

F

Low-, medium-, and high-density

Urban pen pace

Shallow arsh/ et eadow

Deep arsh

Flood-plain orest

B

Illinois Beach State Park boundary

Watershed boundary

Subwatershed boundary

Stream

Gage location and name

gricultural crops

g

orested land

urban

o s

m w m

m

f

Open water

arren and exposed land

Southern Unit Illinois

Beach State Park

Northern Unit Illinois

Beach State Park

Chiwaukee Prairie

State Natural Area

Dead Dog Cr.

Kenosha County

Lake County

WISCONSIN

ILLINOIS

Cr

DD4

DD1

DD3

W2

DR1

DR3

DR2

DR1
Introduction 11

Kellogg Creek and Dead Dog Creek

The Kellogg Creek Watershed is in northeastern corner of 

Lake County and extends into southern Wisconsin. The watershed is 11.3 mi2

, of which Dead Dog Creek drains approximately 2.1 mi2

 (Lake County Stormwater Management Commission, 2008a). The population within the Kellogg Creek 

Watershed increased from about 17,500 in 1970 to 24,400 in 

2000, with a projected population of about 35,000 in 2020 

(Lake County Stormwater Management Commission, 2008a). 

The coastal wetland complex accounts for approximately 

25 percent of the total watershed area. Agricultural land use 

accounts for approximately 17 percent of the total watershed 

area. Residential and other urban land uses account for most 

of the remainder of land use in the watershed. By 2020 it is 

expected that land for agricultural and open space uses will 

be reduced within the watershed and that urban land uses, 

especially single-family homes, will increase (Lake County 

Stormwater Management Commission, 2008a).

Kellogg Creek is a straight, channelized creek with high 

banks that traverses the wetland complex in the NUIBSP 

(figs. 1 and 5). The banks of Kellogg Creek have been raised 

by deposition of dredging spoil and other types of fill, so the 

creek has minimal hydraulic interaction with the surrounding 

wetland complex and is not included as part of this investigation. The investigation in the northern part of the study area 

focuses on the Dead Dog Creek part of the watershed.

Dead Dog Creek and smaller intermittent drainages to the 

north and south drain a predominately urban area to the west 

of the SBNP, CPSNA, and the NUIBSP (fig. 5). Flow of Dead 

Dog Creek through the wetland complex in the northern part 

of the study area is not well defined because of the complex 

flow through the ditches and culverts as well as through and 

around the dune and swale topography. However, the general 

direction of flow is west to east toward gages W1, W2, and 

DD3, which is where the watershed drains to Lake Michigan 

(table 3). 

Land use in the Dead Dog Creek Watershed was characterized for areas upstream from gages DD1, DD3, and DD4 

(fig. 5) by using geographic information system (GIS) analysis. Gage DD1 is on the bluff approximately 500 ft west of the 

point where Dead Dog Creek enters the SBNP (figs. 2 and 3; 

table 3). Gage DD4 is downstream from a storm drain on the 

eastern side of a culvert beneath the railroad tracks where one 

of the small ancillary drainages in the Dead Dog Creek Watershed flows into the wetland area on the NUIBSP. Gage DD3 is 

beside a ditch at the outlet to Lake Michigan. The watershed 

at gage DD1 has a drainage area of about 1.5 mi2

. Land use 

within this part of the watershed is 43 percent agricultural 

cropland, 31 percent natural (urban open space, park, forest, 

wetland), and about 26 percent urban land. The watershed 

upstream from gage DD4 has a drainage area of 0.4 mi2. Land 

use within the watershed for DD4 is about 72 percent urban, 

with the remaining being natural. The watershed above gage 

DD3 drains about 3.5 mi2

. Land use within the watershed for 

gage DD3 is 37 percent agricultural cropland, about 38 percent 

natural (about 2 percent is wetland), and about 25 percent 

urban land. 

Bull Creek and Dead River

The Bull Creek and Dead River Watershed is immediately south of the Kellogg Creek Watershed. A series of ponds 

and wetlands in the western part of the SUIBSP separates Bull 

Creek from the Dead River (fig. 4). Bull Creek occupies the 

upper part of the watershed and the Dead River occupies the 

lower part. The watershed is 11.0 mi2 in area. The population 

within the watershed increased from about 44,000 in 1970 to 

about 51,150 in 2000, with a forecast population of 51,225 in 

2020 (Lake County Stormwater Management Commission, 

2008b). The coastal complex accounts for 2.9 mi2 of the total 

watershed area. Agricultural land use accounts for approximately 2 percent of the total watershed area. Residential and 

other urban land uses, including forested urban land and open 

space, account for approximately 60 percent of the land use in 

the watershed. By 2020 it is expected that land for agricultural 

and open space uses will be reduced or eliminated within the 

watershed and that urban land uses, especially single-family 

homes, will increase (Lake County Stormwater Management 

Commission, 2008b). 

Bull Creek drains an urbanizing area to the west of the 

SUIBSP (fig. 5). Bull Creek enters the SUIBSP and flows 

into a series of man-made ponds and Typha spp.-dominated 

wetlands, then forms the headwaters of the Dead River near 

gage DR2. The Dead River meanders through high-quality 

dune and swale communities until reaching Lake Michigan 

near gage DR3. 

The watershed for Bull Creek was characterized upstream 

from gage DR1, on the bluff west of the SUIBSP (table 3). 

The watershed for the Dead River was characterized at gage 

DR2, downstream from the ponds on the western part of the 

SUIBSP, and at gage DR3, at the outlet to Lake Michigan 

(fig. 5). The Bull Creek Watershed above gage DR1 has a 

drainage area of about 5.7 mi2. Land use within the watershed 

for gage DR1 is about 50 percent urban, about 42 percent natural, and about 8 percent agricultural cropland. The watershed 

above gage DR2 has a drainage area of 6.2 mi2. Land within 

the watershed for gage DR2 is about 48 percent urban, about 

45 percent natural, and about 7 percent agricultural cropland. The watershed above gage DR3 has a drainage area of 

11.0 mi2. Land use within the watershed for gage DR3 is about 

55 percent natural (of which about 2.5 percent is wetland), 

about 41 percent urban, and 4 percent agricultural cropland. 
12 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Table 3. Gage locations and well locations with associated plant community information in the vicinity of the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, near Winthrop Harbor and Waukegan, Illinois. Locations 

of gages and wells are shown in figures 2–4. 

[SBNP, Spring Bluff Nature Preserve; NUIBSP, Northern Unit Illinois Beach State Park; na, not assigned; CPSNA, Chiwaukee Prairie Natural Area; SUIBSP, 

Southern Unit Illinois Beach State Park]

Staff 

gage

U.S. Geological Survey 

station number Hydrologic overview

DD1 4087300 In main channel of Dead Dog Creek near base of bluff about 300 feet west of SBNP. Water flows 

into SBNP.

DD2 4087316 In ditch at culvert in wetland area immediately north of 7th Street in SBNP. Water typically stagnant. Can flow south if water is high.

DD3 4087320 In ditch at culvert in northern part of NUIBSP. Outlet of Dead Dog Creek to Lake Michigan.

DD4 4087318 Located at railroad culvert downstream of storm drain. Water flows to the NUIBSP.

SG1 na In ditch in wetland area immediately south of 7th Street in NUIBSP. Water typically stagnant. Can 

flow south if water is high.

W1 4087280 In southern part of CPSNA in swale. Water eventually flows to Lake Michigan via outlet north of 

Illinois State line.

W2 4087285 In northeastern part of SBNP in wetland. Water flows to Lake Michigan via nearby manhole 

attached to storm drain.

W3 4087312 In western part of SBNP in pond surrounded by wetland. Water typically stagnant but can flow to 

east and north.

W4 4087317 In northern part of NUIBSP in wetland. Water typically stagnant.

DR1 4087405 In main channel of Bull Creek near top of bluff about 1,000 feet west of SUIBSP. Water flows into 

SUIBSP.

DR2 40874083 In main channel of Dead River at culvert near bend in road in wetland area downstream of 

retention ponds. Water typically stagnant, but flow toward Lake Michigan.

DR3 40874087 In main channel of Dead River about 300 feet west of Lake Michigan. Water stagnant behind dam 

or flows into lake depending on conditions.

A na In SUIBSP in sedge meadow adjacent to well 21.

B na In SBNP in emergent marsh adjacent to well 1.

C na In SBNP in emergent marsh adjacent to well 5.

D na In SBNP in emergent marsh adjacent to well 7.

E na In SBNP in emergent marsh adjacent to well 9.

F na In SBNP in emergent marsh adjacent to well 12.

G na In CPSNA in sedge meadow adjacent to well 14.

H na In CPSNA in emergent marsh adjacent to well 18.
Introduction 13

Table 3. Gage locations and well locations with associated 

plant community information in the vicinity of the Spring Bluff 

Nature Preserve, Chiwaukee Prairie State Natural Area, and 

Illinois Beach State Park, near Winthrop Harbor and Waukegan, 

Illinois. Locations of gages and wells are shown in figures 2–4. 

—Continued 

[SBNP, Spring Bluff Nature Preserve; NUIBSP, Northern Unit Illinois Beach 

State Park; na, not assigned; CPSNA, Chiwaukee Prairie Natural Area; 

SUIBSP, Southern Unit Illinois Beach State Park]

Well U.S. Geological Survey 

station number Hydrologic overview

1 na In SBNP in emergent marsh.

2 na In SBNP in mesic prairie.

3 na In SBNP in emergent marsh.

4 na In SBNP in mesic prairie.

5 na In SBNP in emergent marsh.

6 na In SBNP in wet prairie.

7 na In SBNP in emergent marsh.

8 na In SBNP in wet-mesic prairie.

9 na In SBNP in emergent marsh.

10 na In SBNP in wet prairie.

11 na In SBNP in wet-mesic prairie.

12 na In SBNP in emergent marsh.

13 na In CPSNA in mesic prairie.

14 na In CPSNA in sedge meadow.

15 na In CPSNA in mesic prairie.

16 na In CPSNA in wet prairie.

17 na In CPSNA in mesic prairie.

18 na In CPSNA in emergent marsh.

19 na In NUIBSP in panne.

20 na In SUIBSP in wet prairie.

21 na In SUIBSP in sedge meadow.

22 na In SUIBSP in wet prairie.

Meteorological Data

Temperature and precipitation were measured at a 

weather station in Kenosha, Wis. (station 474174), maintained 

by the National Oceanic and Atmospheric Administration. 

This station is approximately 6 mi north of the study area and 

is the closest weather station with a lakeshore setting that is 

similar to the study area. The actual data for this station were 

obtained from the Midwestern Regional Climate Center (Midwestern Regional Climate Center, 2008). Normal precipitation 

values and the above-normal and below-normal range thresholds at this station were calculated by the National Water and 

Climate Center (National Water and Climate Center, 2008) 

on the basis of 1971–2000 data (National Water and Climate 

Center, 1995). Conditions at Kenosha are assumed to be representative of the study area.

Monthly precipitation during the investigation ranged 

from 0.69 in. during November 2007 to 11.50 in. during 

August 2007 (table 4). Precipitation totals during the period 

of investigation were more than 7 in. above the mean. Most of 

this excess precipitation occurred in August 2007, when precipitation was more than 7 in. greater than normal. Precipitation data indicate hydraulic conditions during the investigation 

were wetter than average, further indicating that water levels 

and chemical and sediment loads during the investigation may 

have been higher than typical.

Mean monthly temperature at the Kenosha station during 

the investigation ranged from 22.5°C during August 2007 to 

-5.28°C during February 2008 (table 4). Mean temperatures 

during the investigation were somewhat higher than typical, 

implying that evapotranspiration during the investigation also 

may have been higher than typical.

The date of first autumnal -2.2°C measurement during the 

investigation was November 15, 2007. The date of last vernal 

-2.2°C during the investigation was March 30, 2008. These 

dates approximate the period when there was no plant growth 

during the investigation. The remainder of the period of investigation approximates the growing season, when plant growth 

can result in evapotranspiration and nutrient uptake.
14 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Topography

The primary surface features in the study area are the 

bluff in the western part of the study area, the dune and swale 

topography from the bluff eastward toward Lake Michigan, 

and the beach topography at the lakeshore (figs. 6 and 7). 

Roadbed for the train tracks at the base of the bluff near the 

western edge of the wetland complex also forms a small topographic ridge throughout the study area.

In the northern part of the study area in the vicinity of 

the SBNP, CPSNA, and the NUIBSP, the elevation of the land 

surface in the upland area near the top of the bluff exceeds 

610 ft (all elevations relative to North American Vertical 

Datum of 1988 (NAVD 88)), whereas the elevation of the 

railroad tracks is about 600 ft (fig. 6). Land-surface elevation 

near the lakeshore ranges from about 577 ft near the 2007 

shoreline (http://www.in.gov/dnr_old/water/lake_michigan/

coastal/pdf/03WaterLevelTable1981-2008LakeMichigan.pdf, 

accessed May 7, 2009) to about 596 ft at the parking lots south 

of the North Point Marina. Land-surface elevation in the wetland complex in the northern part of the study area between 

the bluff and the shoreline ranges from 585 to 590 ft. The low 

points (about 585 ft) are in the ditches and interdunal swales. 

High points are on the ridges and dunes in the upland prairie

and savanna communities. Additionally, locally higher elevation is associated with several man-made features in the northern part of the study area, including 7th Street, the offshoot 

from the railroad near the southwestern edge of the SBNP, the 

marina roads and parking lots at the eastern edge of the SBNP, 

the access road running north-south through the eastern part 

of the SBNP, a man-made berm between the CPSNA and the 

SBNP, and north-south-running grass roads in the western and 

central parts of the NUIBSP. 

In the southern part of the study area west of the SUIBSP, 

land-surface elevation near the top of the bluff is higher than 

620 ft (fig. 7). Land surface in most of the SUIBSP ranges 

from 582 to 590 ft and along the railroad tracks is about 596 ft. 

Elevation near the lakeshore at the SUIBSP ranges from about 

577 ft near the 2007 shoreline to about 590 ft at the top of 

the dunes adjacent to the lake. Similar to the north part of the 

study area, lower points are commonly interdunal wetlands 

and ditches, and high points are commonly prairie and savanna 

communities on sand ridges.

Table 4. Climate data, May 2007–August 2008, Kenosha, Wisconsin. 

[Data from Midwest Regional Climate Center, 2008; -, less than normal; +, more than normal]

Month and year Total precipitation 

(inches)

Departure from 

normal (inches)

Mean temperature 

during investigation 

(degrees Celsius)

Departure from normal 

(degrees Celsius)

May 2007 2.14 -1.23 13.83 1.50

June 2007 3.24 -.35 19.61 1.83

July 2007 3.81 .13 22.17 .78

August 2007 11.50 7.31 22.50 1.50

September 2007 .84 -2.65 18.44 1.56

October 2007 2.82 .35 14.17 3.44

November 2007 .69 -1.99 4.17 .44

December 2007 3.77 1.68 -2.39 .50

January 2008 1.70 .03 -4.61 1.39

February 2008 4.03 2.74 -5.28 -1.89

March 2008 4.30 1.96 .33 -1.17

April 2008 4.18 .33 7.50 .89

May 2008 2.62 -.75 11.39 -.94

June 2008 5.29 1.70 19.06 1.28

July 2008 5.16 1.48 21.83 .44

August 2008 1.09 -3.10 21.78 .78

Total, May 2007 through 

August 2008

57.18 7.64 Not applicable Not applicable
0 0.25 0.5 MILE

0 0.25 0.5 KILOMETER

Dead Dog Creek

Dead

k

D

e

o

e

g

r C

Lake Michigan

Access road

WISCONSIN

ILLINOIS

Spring Bluff

Nature Preserve

Chiwaukee Prairie

State Natural Area

87°49' 87°48'30" 87°48'

42°29'30"

42°29'

Elevation for Illinois derived from Lake County Forest PreservePlanning Office contour data, 2005, 2-foot contour interval.Elevation for Wisconsin derived from U.S. Geological SurveyNational Elevation Dataset (NED), 2003, 10-meter resolution.

North

Point

Marina

Northern Unit

Illinois Beach State Park

7th Street

EXPLANATIO

Elevation, in feet above No Vertical Datum of 1988

Water577 to 581581 to 582582 to 583583 to 584584 to 585

Figure 6. Topography in the vicinity of the Spring Bluff Nature Preserve, Winthrop Harbor, Illinois. 
Bull Dead River Creek Lake Michigan

87°50' 87°49'30" 87°49' 87°48'30" 87°48'

42°25'30"

42°25'

42°24'30"

0 0.25 0.5 MILE

0 0.25 KILOMETER 0.5

Elevation derived from Lake County Forest Preserve Planning Officecontour data, 2005, 2-foot contour interval.

EXPLA

Elevation, in feet a Vertical Datum 

Water577 to 581581 to 582582 to 583583 to 584584 to 585

Figure 7. Topography in the vicinity of the Southern Unit of the Illinois Beach State Park near Waukegan, Illinois. 
Introduction 17

Methods of Investigation

Water-Level Measurement

Surface-water levels were measured periodically using 

USGS staff gages at locations DD1, DD2, W1, W2, W3, W4, 

DR1, DR2, and DR3; and ISGS staff gages installed at locations A–H (table 5; figs. 2, 3, and 4). Staff gages were bolted 

to metal posts, which were driven a minimum of 2 ft into 

the sediment. Surface-water levels were measured periodically from a fixed point of reference at locations DD3, DD4, 

and SG1 by use of an electric water-level indicator (electric 

tape measure). Staff gages and electric water-level indicators were calibrated to 0.01 ft. For the purposes of this report 

“gage” refers to any location where surface-water levels were 

measured, whereas “staff gage” refers to the device used to 

measure surface-water levels at many of the gages.

Surface-water levels were measured every 15 minutes 

during May 24–November 1, 2007, and during March 18–

June 11, 2008, at gages DD1, DD2, W1, W3, W4, and DR2 

by use of a pressure transducer and water-level logger. 

Surface-water levels also were measured every 15 minutes 

during May 24–November 1, 2007, at gage W2. Gage W2 was 

submerged during the spring of 2008, so a water-level logger 

could not be reinstalled during this period. The transducers 

were securely affixed to the metal post that held the staff gages 

and were periodically serviced to reduce fouling. Transducers 

were capable of detecting changes in water level of 0.015 ft. 

Water levels measured by the pressure transducers were 

compared to periodic readings from the staff gage to verify the 

accuracy of the transducer data. 

Groundwater levels were measured in shallow monitoring 

wells 1–22 during July 2007–August 2008. These wells were 

designed to monitor the zone of saturation in the near-surface 

sediments, according to the methods of Miner and Simon 

(1997). Eighteen wells were installed along three transects in 

the CPSNA and the SBNP (fig. 3), one well at a location in 

the NUIBSP and three wells along one transect in the SUIBSP 

(fig. 4). Locations for well installation were chosen to represent the range of wetland and non-wetland plant communities 

in the sites and to include areas with native and nonnative vegetation for comparison. Transects were oriented west to east 

and generally perpendicular to the orientation of dune ridges 

and interdunal swales, thereby intersecting as many different 

vegetation communities as possible. This approach allowed 

comparison of hydroperiod and floristic composition and quality in areas of greater or lesser dominance by Typha spp. and 

Phragmites australis. Well 19 was installed in the NUIBSP 

in a high-quality panne to document hydrologic conditions 

in that globally rare wetland type. All wells were constructed 

with threaded 2-in. PVC casing and 0.01-in. slotted manufactured PVC screens that were 1-ft long. Wells were generally 

installed to a depth of 2.5 ft, with wells in topographically 

higher positions (2, 4, and 17) being installed slightly deeper 

to ensure they reached depths with soil-zone saturation. All 

screens were fitted with a bottom cap with a drainage hole. 

The annulus between the well screen and soil was packed with 

quartz sand with a grain size of 0.038 in., and the remainder of 

the annulus was then backfilled to land surface with medium 

bentonite chips. The minimum length of the annular seal was 

1 ft.

Groundwater levels were measured by using an electronic water-level measuring tape approximately every 2 to 

4 weeks. In addition, pressure transducers and dataloggers 

were installed in July 2007 in wells 1, 3, 5, 6, 7, 9, 12, 14, 16, 

18, 19, and 21. The dataloggers recorded water levels every 

6 hours to an accuracy of 0.01 ft through August 2008.

Surveying

The locations of all USGS surface-water gages were surveyed by using a hand-held global positioning system (GPS) 

unit to a horizontal accuracy of about 3 ft and reported as 

latitude and longitude. The elevation of the reference point for 

gages DD3 and SG1 and a reference point on the staff gages 

was surveyed to 0.01 ft by using rod and level techniques. 

Staff gages were surveyed in June 2007 and resurveyed in 

May 2008 to ensure that the gage reading could be corrected, 

if necessary, for movement during the winter. All elevations 

were referenced to NAVD 88.

ISGS gage and well locations were determined by using 

a GPS unit and were differentially corrected to an accuracy of 

1 ft. Instrument elevations were determined with either optical 

level or total station to an accuracy of 0.01 ft. Onsite elevation 

control was tied to benchmarks set by LCFPD personnel.

Surface-Water Discharge

In addition to the continuous measurement of stage, 

stream discharge was measured periodically (table 5) at gages 

DD1, W1, DD3, DD4, DR1, DR2, and DR3 according to 

standard USGS methods (Rantz and others, 1982). In general, these methods include the measurement of stream depth 

and stream velocity at 20 or more vertical sections across 

the stream; stream discharge is then computed from these 

measurements. 
18 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Table 5. Information on gages and wells in the vicinity of the Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, 

and Illinois Beach State Park, near Winthrop Harbor and Waukegan, Illinois. Locations of wells and gages are shown in figures 2–4. 

—Continued 

[na, not assigned]

Gage 

U.S. Geological 

Survey 

station number

Latitude 

(degrees minutes 

seconds)

Longitude 

(degrees minutes 

seconds)

Data collected

DD1 4087300 42° 28’ 59” 87° 49’ 05” Continuous and intermittent water levels. Intermittent discharge and 

water quality

DD2 4087316 42° 28’ 57” 87° 48’ 46” Continuous and intermittent water levels. Intermittent discharge and 

water quality

DD3 4087320 42° 28’ 43” 87° 47’ 59” Intermittent water levels, discharge, and water quality

DD4 4087318 42° 28’ 43” 87° 48’ 56” Intermittent water levels, discharge, and water quality

SG1 na 42° 28’ 56” 87° 48’ 46” Intermittent water levels, discharge, and water quality

W1 4087280 42° 29’ 34” 87° 48’ 38” Continuous and intermittent water levels. Intermittent discharge and 

water quality

W2 4087285 42° 29’ 28” 87° 48’ 20” Continuous and intermittent water levels. Intermittent discharge and 

water quality

W3 4087312 42° 29’ 08” 87° 48’ 51” Continuous and intermittent water levels, intermittent water quality

W4 na 42° 28’ 52” 87° 48’ 39” Continuous and intermittent water levels, intermittent water quality

DR1 4087405 42° 25’ 42” 87° 49’ 29” Continuous and intermittent water levels. Intermittent discharge and 

water quality

DR2 40874083 42° 25’ 14” 87° 49’ 02” Continuous and intermittent water levels. Intermittent discharge and 

water quality

DR3 40874087 42° 24’ 32” 87° 48’ 12” Intermittent water levels, discharge, and water quality

A na 42° 24’ 25” 87° 49’ 13” Intermittent water levels

B na 42° 28’ 58” 87° 48’ 34” Intermittent water levels

C na 42° 28’ 58” 87° 48’ 30” Intermittent water levels

D na 42° 29’ 32” 87° 48’ 55” Intermittent water levels

E na 42° 29’ 32” 87° 48’ 51” Intermittent water levels

F na 42° 29’ 30” 87° 48’ 47” Intermittent water levels

G na 42° 29’ 47” 87° 48’ 50” Intermittent water levels

H na 42° 29’ 46” 87° 48’ 44” Intermittent water levels

Well

U.S. Geological 

Survey 

station number

Latitude 

(degrees minutes 

seconds)

Longitude 

(degrees minutes 

seconds)

Data collected

1 na 42° 28’ 58” 87° 48’ 34” Continuous and intermittent water levels, continuous water quality

2 na 42° 28’ 58” 87° 48’ 33” Intermittent water levels

3 na 42° 28’ 58” 87° 48’ 32” Continuous and intermittent water levels

4 na 42° 28’ 59” 87° 48’ 31” Intermittent water levels

5 na 42° 28’ 58” 87° 48’ 30” Continuous and intermittent water levels

6 na 42° 29’ 32” 87° 48’ 56” Continuous and intermittent water levels

7 na 42° 29’ 32” 87° 48’ 55” Continuous and intermittent water levels, continuous water quality

8 na 42° 29’ 32” 87° 48’ 53” Intermittent water levels

9 na 42° 29’ 32” 87° 48’ 51” Continuous and intermittent water levels

10 na 42° 29’ 32” 87° 48’ 50” Intermittent water levels

11 na 42° 29’ 30” 87° 48’ 49” Intermittent water levels

12 na 42° 29’ 30” 87° 48’ 47” Continuous and intermittent water levels, continuous water quality

13 na 42° 29’ 46” 87° 48’ 51” Intermittent water levels
Introduction 19

Table 5. Information on gages and wells in the vicinity of the Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, 

and Illinois Beach State Park, near Winthrop Harbor and Waukegan, Illinois. Locations of wells and gages are shown in figures 2–4. 

—Continued 

[na, not assigned]

Well

U.S. Geological 

Survey 

station number

Latitude 

(degrees minutes 

seconds)

Longitude 

(degrees minutes 

seconds)

Data collected

14 na 42° 29’ 47” 87° 48’ 50” Continuous and intermittent water levels

15 na 42° 29’ 47” 87° 48’ 49” Intermittent water levels

16 na 42° 29’ 47” 87° 48’ 47” Continuous and intermittent water levels

17 na 42° 29’ 46” 87° 48’ 45” Intermittent water levels

18 na 42° 29’ 46” 87° 48’ 44” Continuous and intermittent water levels, continuous water quality

19 na 42° 27’ 10” 87° 48’ 10” Continuous and intermittent water levels

20 na 42° 24’ 24” 87° 49’ 15” Intermittent water levels

21 na 42° 24’ 25” 87° 49’ 13” Continuous and intermittent water levels

22 na 42° 24’ 25” 87° 49’ 12” Intermittent water levels

Water-Quality Sampling 

Surface-water samples were collected periodically at 

gages DD1, DD3, DD4, W1, W3, W4, DR1, DR2, and DR3. 

For the purposes of this report, periodic sampling refers to 

the intermittent water-quality sampling activities on May 31, 

June 27, July 30, August 29, September 18, and November 27, 

2007, as well as on April 2 and May 15, 2008. Dissolved 

oxygen, specific conductance, pH, and temperature (referred 

to hereafter as “field parameters”) were measured (when possible) during periodic sampling prior to sample collection with 

a calibrated multiparameter water-quality measuring instrument according to USGS protocols (Wilde and others, 1998). 

Samples collected during periodic sampling were analyzed for 

concentrations of suspended sediment, dissolved nitrate plus 

nitrite (as nitrogen) (Fishman and Friedman, 1989), dissolved 

phosphorous (according to U.S. Environmental Protection 

Agency method 365.1), and dissolved chloride (Fishman and 

Friedman, 1989; table 5). Depth-integrated samples were collected from a single point in the stream or wetland. Samples 

to be analyzed for dissolved nitrate plus nitrite, dissolved 

phosphorous, and dissolved chloride were filtered through a 

0.45-μm filter prior to preservation with ice and shipment. 

Concentrations of dissolved nitrate plus nitrite, dissolved 

phosphorous, and dissolved chloride were determined by the 

USGS National Water Quality Laboratory in Denver, Colo. 

Samples to be analyzed for dissolved nitrate plus nitrite, dissolved phosphorous, and dissolved chloride (hereafter referred 

to as “chloride”) were shipped to the laboratory for analysis within 24 hours of collection and were analyzed within 

accepted holding times. 

In addition to the periodic sampling, suspended-sediment 

samples were collected at gages DD1 or DR1 before, during, 

and after selected storm events. These storm-event samples 

were collected by an automatic sampler at intervals of 30 

to 180 minutes as programmed by the person operating the 

sampler. Storm-event samples were collected from other gages 

during some of these events. 

Suspended-sediment concentrations were determined by 

the USGS Sediment Laboratory in Louisville, Ky., in accordance with the lab’s standard operating procedures (Shreve 

and Downs, 2005). Samples to be analyzed for suspended-sediment concentration were covered to protect them from light 

and were analyzed within 12 months of collection.

Duplicate samples were collected to determine the variability of field collection and laboratory analyses. Comparisons of concentrations from samples and their field duplicates 

show close agreement, indicating an acceptable level of variability from collection and laboratory practices

In addition to periodic and storm-event sampling, continuous measurements of surface-water quality were collected 

using multiparameter water-quality sensors and dataloggers. Multiparameter water-quality instruments were used 

to measure specific conductance and temperature of surface 

water adjacent to (outside of) wells 1, 7, 12, 18, and 21 every 

6 hours during October 2007–July 2008. Multiparameter 

instruments were used to measure the turbidity, specific conductance, and temperature of surface water every 6 hours at 

gages W1, DD1, and W3 for part or all of the period between 

October 2007 and July 2008. Multiparameter instruments 

were serviced approximately every 2 months and recalibrated. 

Incorrect readings that resulted when the instruments were dry, 

frozen, or otherwise malfunctioning were removed according 

to procedures in Wagner and others (2000). The sensors on the 

instruments were deployed approximately at land surface to 

measure the quality of surface water rather than groundwater. 
20 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Vegetation Monitoring

Vegetation was monitored within eight 10.76-ft2 quadrats near each monitoring well (1–22) for species presence 

and abundance. Abundance was measured by a visual estimate 

of absolute percent cover of plants rooted within the quadrat. 

The abundance of two invasive species of particular interest, Typha spp. and Phragmites australis, were measured 

by counting the number of rooted individuals within each 

quadrat. Because hybridization between Typha angustifolia

and T. latifolia has been observed (Smith, 1967), and because 

genetic studies indicate that morphological characteristics are 

not good indicators for identification of Typha spp. because 

of the variability found in hybrids (Marburger and others, 

2005), all Typha species were lumped into Typha spp. for this 

investigation.

At each well, quadrats were positioned at 6.5 and 13 ft 

from the well in each cardinal direction for a total of eight 

quadrats sampled near each well. The 6.5-ft radius from the 

well avoided areas of disturbance adjacent to the well but 

kept quadrats close enough to the well to be representative. If 

there was a change in topography within 13 ft of the well that 

resulted in a distinct change of community type, quadrats were 

repositioned in a different cardinal direction at 20 or 26 ft 

from the well to prevent sampling in a community type that 

was not representative of the well vicinity. Wells 6–12 were 

sampled on August 28, 2007 (prior to the start of management 

to control Typha spp. in the surrounding area), and wells 1–5 

and 12–22 were sampled on June 30 and July 1, 2008.

Data collected from the quadrats were entered into the 

Floristic Quality Assessment and Computer Applications program (Swink and Wilhelm, 1994; Wilhelm and Masters, 2006) 

and the Species Richness Indices Spreadsheet Program for 

Graminoid and Herbaceous Plant Communities (Bowles and 

Jones, 2007) to quantify species richness per quadrat, average 

wetness, mean coefficient of conservatism (all species and 

native only), species richness index (all species and native 

only), density of Typha spp. per quadrat, density of Phragmites australis per quadrat, and total species richness of all 

eight quadrats sampled per well. Classification of communities 

was based on the Chicago Wilderness Community Classification (Chicago Wilderness, 1999) and determined by floristic 

composition and average wetness. 

To explore the relations between hydrological and biological conditions in a quantitative manner, a correlation matrix 

was constructed for selected parameters. Pearson correlation 

coefficients (R2

) were calculated for various data subsets; 

an R2 value exceeding 0.70 was considered to show a high 

degree of correlation. Biological data sets (Typha spp. relative 

importance, Phragmites australis relative importance, mean 

vegetative wetness, native species mean coefficient of conservatism, and native species richness index) were calculated 

from vegetation-monitoring data. For land-surface elevations, 

the 2007 survey data were used. The rest of the data (mean 

depth-to-water, growing season mean depth-to-water, days 

of inundation, and growing season days of inundation) were 

derived from manual and datalogger water-level measurements. For wells where continuous water-level measurements 

were available, total days of surface inundation were calculated. For wells without continuous data, total days of inundation were calculated by interpolating between manual waterlevel measurements. Data from nearby continuous recorders 

were used to constrain the timing of wetting and drying events 

in the interpolation. Plant growth and soil microbial activity (which creates the anaerobic conditions favoring plants 

adapted to wetter conditions) are both affected by soil temperatures (Mitsch and Gosselink, 2007). For this reason, mean 

depth-to-water and days of inundation were estimated for the 

growing-season period as well as for the entire monitoring 

period. The growing-season dates were based on climate data 

from the Kenosha, Wis., station (National Water and Climate 

Center, 2008). 

Surface-Water Hydrology

The hydrology of the creeks and wetlands in the study 

area is affected by the timing and amount of precipitation, 

evapotranspiration, the amount of flow into and out of the 

study area, interaction between surface water and groundwater, stage of Lake Michigan, and a variety of other factors 

(Visocky, 1976; Kubillus, 1994). 

Water Levels Through Time

Water levels collected at gages DD1 (fig. 8) and W1 

(fig. 9) demonstrate that surface-water levels in and near the 

wetland complex vary in response to meteorologic events (primarily precipitation, snowmelt, and evapotranspiration). These 

phenomena can affect water levels over periods of hours to 

months. 

Seasonal variations in meteorologic conditions (primarily 

variations in precipitation and temperature) had the greatest 

affect on surface-water levels during the investigation. Typically, precipitation in Illinois is highest in spring through summer, peaking in late spring to early summer. Evapotranspiration is highest in summer and greatly reduces overland runoff 

and infiltration to groundwater (Hensel, 1992). Therefore, 

water levels in streams and wetlands are typically highest during spring, decline during summer and fall, and begin rising 

in winter through spring. This is the pattern observed in the 

wetlands and streams in the study area (figs. 8 and 9), where 

water levels declined overall from the start of monitoring in 

May 2007 through early August 2007 in response to reduced 

runoff from precipitation and increased evapotranspiration. 
Introduction 21

DATE

583.0

583.5

584.0

584.5

585.0

585.5

586.0

586.5

587.0

587.5

588.0

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June

2007 2008

Land surface

WATER LEVEL, IN FEET ABOVE NORTH 

AMERICAN VERTICAL DATUM OF 1988

595.5

596.0

596.5

597.0

597.5

598.0

598.5

599.0

599.5

WATER LEVEL, IN FEET ABOVE NORTH 

AMERICAN VERTICAL DATUM OF 1988

DATE

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June

2007 2008

Stream bottom

Figure 8. Water levels in Dead Dog Creek at gage DD1, May 25, 2007–June 11, 2008, in the vicinity of the Spring Bluff Nature Preserve, 

Winthrop Harbor, Illinois. 

Figure 9. Water levels at gage W1, May 24, 2007–June 11, 2008, in the vicinity of the Spring Bluff Nature Preserve, Winthrop Harbor, 

Illinois. 
22 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Water levels in the wetland complex were relatively high during most of August 2007 in response to a series of unusually 

large rainstorms (table 4; fig. 10) and were stable to slightly 

declining during September through mid-October 2007. Water 

levels began a general rise from mid-October 2007 through 

mid-April 2008 in response to decreased evapotranspiration 

and increased runoff from precipitation and snowmelt episodes. Water levels in the wetland complex then declined from 

mid-April 2008 through early June 2008 as, once again, runoff 

from precipitation decreased and evapotranspiration increased. 

Seasonal variations in meteorologic conditions tended to produce moderate to large changes in water levels (0.5 to about 

2 ft) that lasted from a couple weeks to several months.

Superimposed on the seasonal trends in water levels are a 

number of shorter-term fluctuations in water levels associated 

with individual rain events during the spring, summer, and 

fall, as well as snowmelt events during the winter and spring. 

Examples of water-level responses to precipitation events 

at gages DD1 and W1 (figs. 8 and 9) can be seen on June 8, 

August 7, and August 19 and 20, 2007, and April 10 and 

June 8, 2008. The seasonal decline in water levels observed 

during June and July 2007 likely would have continued 

through October if not for the unusually large precipitation 

events in August, which resulted in a marked, prolonged 

increase in water levels in the study area. Water-level 

responses affected by precipitation and snowmelt events were 

present on January 9, and March 26, 2008. Precipitation events 

produced changes in water levels that tended to be proportionate to the amount of precipitation but could be as much as 3 ft 

and could last for periods of a few days to a few weeks.

Finally, water levels at gage DD1 on Dead Dog Creek 

and some of the gages in the wetlands varied during the course 

of the day as the result of diurnal variations in evapotranspiration during the growing period. Evapotranspiration includes 

both direct evaporation from water surfaces and evaporation 

from leaves of transpiring plants. These processes are directly 

affected by temperature, wind, and solar radiation, which 

typically are higher during the day and lower at night (Mitsch 

and Gosselink, 2007). The effect of these processes on water 

levels tends to be cumulative over the course of the day. As a 

result, daily water levels varied by as much as 0.10 ft. Water 

levels typically were highest during the early morning hours 

before sunrise, decreased during the day, and reached minimum values near sundown, at which time water levels began 

to increase (fig. 11). Evapotranspiration effects were observed 

during about June 16–September 25, 2007. Evapotranspiration 

effects were not observed during 2008 prior to the termination 

of intensive water-level monitoring on June 11, 2008.

DATE

0.0

0.5

1.0

1.5

2.0

2.5

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June

PRECIPITATION, IN INCHES

2007 2008

Figure 10. Precipitation measured at the National Oceanic and Atmospheric Administration Station, Kenosha, Wisconsin, 

May 1, 2007–June 30, 2008. 
Surface-Water Hydrology 23

Evapotranspiration rates were estimated on June 24, 

July 12, July 27, September 5, and September 24, 2007, at 

gage DD1 on Dead Dog Creek and at wetland gages DD2, 

DR2, W1, W2, W3 and W4 by use of the water-level-fluctuation method (Mitsch and Gosselink, 2007; table 6). These 

dates were chosen because they cover the entire period when 

evapotranspiration effects were observed and correspond to 

dates when hydrologic conditions were stable and the effects 

of phenomena other than evapotranspiration on water levels 

were minimal or absent. This method relies on analysis of the 

change in water level during the nighttime hours and use of a 

specific yield value to determine the volume of water removed 

by evapotranspiration. Because these are surface-water bodies, 

the specific yield was assumed to be 1.0. Evapotranspiration 

effects were observed during at least four of the five dates 

for which estimates were made at gages DD1, W1, and W4. 

Evapotranspiration effects on water levels were not observed 

at gage DD2 during any of the dates for which estimates were 

made and were not observed at gages DR2, W2, and W3 during at least three of the dates. These gages all monitored areas 

of deep water. Evapotranspiration effects at these gages may 

have been absent because the volume of water evaporated 

and taken up by the plants was minimal compared to the large 

volume of water at these gages.

Evapotranspiration rates at gage DD1 ranged from 0.002 

to 0.13 ft/d (table 6). Evapotranspiration rates at the gages in 

the wetlands (when and where present) ranged from 0.014 to 

0.113 ft/d. Evapotranspiration rates showed no clear variations 

with date or location. 

In addition to evapotranspiration-induced effects and 

precipitation, water levels at gage DR3 also were affected by 

sandbars that frequently block the outlet of the Dead River 

(fig. 12) (Visocky, 1976). Sandbars are formed by the movement of sediment along the shore of Lake Michigan. When the 

force of the river flow is insufficient to erode more sediment 

than is being deposited by the longshore current, sediment 

builds up and a sandbar forms across the mouth of the river. 

The sandbar eventually dams the river, which increases the 

river stage. Eventually the river stage increases to a point 

where the sandbar is breached and the river discharges to Lake 

Michigan. This discharge erodes the sandbar, resulting in a 

decrease in river stage and discharge rate, which allows the 

sandbar to rebuild and the process to repeat.

DATE AND TIME

596.08

596.09

596.10

596.11

596.12

596.13

596.14

June 24, 2007

0:00

June 24, 2007

12:00

June 2 ,5 2007

0:00

June 2 ,5 2007

12:00

June 2 ,6 2007

0:00

WATER LEVEL, IN FEET ABOVE NORTH 

AMERICAN VERTICAL DATUM OF 1988

Figure 11. Water levels at gage DD1 in the vicinity of the Spring Bluff Nature Preserve, Winthrop Harbor, Illinois, June 24 and 25, 2007. 
24 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Table 6. Estimated evapotranspiration rates at selected gages in the vicinity of the Spring Bluff Nature Preserve, Chiwaukee Prairie 

State Natural Area, and Illinois Beach State Park, near Winthrop Harbor and Waukegan, Illinois. Locations of gages and wells are 

shown in figures 2–4. 

[np, not present]

Gage

Estimated rate of evapotranspiration on given date, feet per day Approximate dates when 

evapotranspiration 

06/24/07 07/12/07 07/22/07 09/05/07 09/24/07 effects were observed

DD1 -0.096 -0.13 -0.12 -0.002 -0.11 June 16 through 

September 25

DD2 np np np np np Evapotranspiration not 

clearly observed 

DR2 -.113 .015 np np .064 May 29 through 

September 30

W1 -.023 -.014 -.056 -.017 .079 June 16 through 

September 25

W2 .059 np np np np Evapotranspiration not 

clearly observed 

W3 np np np np -.025 Evapotranspiration not 

clearly observed 

Gage

Estimated rate of evapotranspiration on given date, feet per day Approximate dates when 

evapotranspiration 

effects were observed 06/24/06 07/10/06 07/22/06 09/05/06 09/24/06

W4 -0.038 -0.06 np np -0.017 June 16 through 

September 25

577

578

579

580

581

582

DATE

May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June

2007 2008

Stream bottom

Mean water level in Lake Michigan (577.04 feet), May 2007 through June 2008

No flow on river

Flow observed to Lake Michigan

WATER LEVEL, IN FEET ABOVE NORTH 

AMERICAN VERTICAL DATUM OF 1988

Figure 12. Water levels in the Dead River at gage DR3 in the Southern Unit of the Illinois Beach State Park near Waukegan, Illinois, 

May 24, 2007–June 11, 2008. 
Surface-Water Hydrology 25

Direction and Timing of Surface-Water Flow

Determination of surface-water flow directions within 

the various parts of the study area was based on water-level 

data from April 29, 2008, because there was water at all of 

the gages on this date. Use of this data set allowed the most 

comprehensive understanding of flow directions, including the 

assessment of the exchange of water between the creeks and 

the wetlands. 

Surface-water flow into the SUIBSP in the southern part 

of the study area starts as channelized streamflow in Bull 

Creek (fig. 13). At the base of the bluff, water flows through 

culverts beneath the railroad tracks into the ponds and wetlands in the western part of the SUIBSP. Water then flows via 

the Dead River from the ponds through the rest of the SUIBSP 

past gage DR3 at the mouth of the river. Observations during 

water-level measurement events indicate that Bull Creek and 

the Dead River stayed within their banks for the majority of 

the investigation (table 7; appendix 1). However, water was 

observed flowing from the river channels and the ponds into 

the wetlands in the western part of the SUIBSP during periods 

of high water in spring 2007 and 2008. 

Surface-water flow into the SBNP starts as channelized 

streamflow in Dead Dog Creek and smaller drainages coming 

off the bluff, including drainages in the southern part of the 

CPSNA (fig. 14). At the base of the bluff, surface topography 

flattens and water flows through culverts beneath the railroad 

tracks into the wetlands, swales, ditches, and channels east 

of the railroad tracks, such as those near gages W1, W3, and 

DD2. 

Swales in the northwestern part of the SBNP and southwestern part of the CPSNA allow for the movement of surface 

water between the western parts of the SBNP and CPSNA. 

Topographic lows associated with swales and ditches also 

serve as conduits for flow from the central part of the SBNP 

north toward gage W1. This flow is indicated by the waterlevel elevations in the central part of the SBNP near gages 

W3 and DD2 that typically were about 2–5 ft higher than the 

water-level elevation at gage W1 in the north-central part 

of the wetland (table 7; appendix 1). This northward flow 

is partly through a swale within the topographic high in the 

central part of the SBNP (fig. 6). Historical flow through an 

east-west-oriented ditch in the central part of the SBNP east 

of gage W3 (fig. 14) has been reduced by infilling. Limited 

flow from the central part of the SBNP to the south toward 

the NUIBSP also occurs. A berm associated with an access 

road near the state line north of gages W1 and W2 separates 

the wetlands along much of the central and eastern parts of 

the SBNP and CPSNA (figs. 3 and 6) except where a break 

in the berm allows for southward drainage from the CPSNA. 

Surface-water flow south of the berm and east of gage W1 is 

through a series of man-made ditches and ponds into a channel 

that drains to Lake Michigan. 

Water-level elevations in the north-central part of the 

SBNP at gage W1 typically were about 0.5–1.75 ft lower than 

the water-level elevation at gage W2 in the northeastern part 

of the wetland (table 7; appendix 1). Because these water-level 

elevations indicate the potential for east-to-west flow in this 

area, which was not observed and which is counter to the prevailing flow direction, they indicate that surface water in the 

eastern part of the SBNP was at least partly isolated from surface water in the swales and ditches in the north-central parts 

of the SBNP by the topographically elevated features (ridge, 

access road, buildings) between gages W1 and W2 (compare 

figs. 3 and 6). The water-level elevation at gage W1 was 

higher than at gage W2 during a few measurements, primarily 

during periods of low water at gage W2 during November and 

December 2007. 

Table 7. Summary of water levels at gages in the vicinity of the 

Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural 

Area, and Illinois Beach State Park, near Winthrop Harbor and 

Waukegan, Illinois, May 24, 2007–June 11, 2008. Locations of 

gages are shown in figures 2–4. 

[Bold denotes manual measurements only; NAVD 88, North American 

Vertical Datum of 1988; <, less than; >, greater than; *, partial period of 

record]

Staff 

gage

Minimum measured 

water-level elevation 

(feet above NAVD 88)

Maximum measured 

water-level elevation 

(feet above NAVD 88)

Range 

(feet)

DD1 596.00 598.96 2.96

DD2 587.17 590.55 3.38

DD3 <581.4 582.94 >1.54

DD4 592.87 593.37 .50

SG1 586.29 588.52 2.23

W1 583.57 587.33 3.76

W2* 583.51 >587.05 >3.54

W3 586.90 589.62 2.72

W4 584.64 586.88 2.24

DR1* 592.13 594.49 2.36

DR2 584.30 585.38 1.08

DR3 577.82 581.00 3.18
26 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Figure 13. Surface-water levels and flow directions in the vicinity of the Southern Unit of the Illinois Beach State Park 

near Waukegan, Illinois, April 29, 2008. 

DR1

592.98

EXPLANATION

Open water

Stream

Primary direction of surface-water flow

Secondary component of surface-water flow

Illinois Beach State Park boundary

Surface-water measuring point, identifier, and 

 water-level elevation, in feet above North 

 American Vertical Datum of 1988.

Illinois State Geological Survey gage (A) and 

 well (20-22)

Culvert

20

B L U F F

DR1

592.98

DR2

584.75

DR3

578.60

Bull

Dead River

Creek

Lake

Michigan

87°50' 87°49'30" 87°49' 87°48'30" 87°48'

42°25'30"

42°25'

42°24'30"

0 0.25 0.5 MILE

0 0.25 KILOMETER 0.5

Base derived from U.S. Geological Survey High-Resolution

Orthoimagery for the Chicago, Ill. urban area, 2005.

Southern Unit

Illinois Beach State Park

20 22

21

A

583.69
Surface-Water Hydrology 27

Figure 14. Surface-water levels, specific conductance, and flow directions in the vicinity of the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Northern Unit of the Illinois Beach State Park near Winthrop 

Harbor, Illinois, April 29, 2008. 

0 0.25 0.5 MILE

0 0.25 0.5 KILOMETER

Dead Dog Creek

Dead

k

D

e

o

e

g r C

North

Point

Marina

Spring Bluff

Nature Preserve

Lake Michigan

Base derived from U.S. Geological Survey High-Resolution

Orthoimagery for the Chicago, Ill. urban area, 2005.

Chiwaukee Prairie

State Natural Area

Northern Unit

Illinois Beach State Park

WISCONSIN

ILLINOIS

87°49' 87°48'30" 87°48'

42°29'30"

42°29'

18

16 17 15 14

13 H

586.80 G 716 587.06

12

11

10 9

8

6 7

F

588.00

1,856 E

588.24

D

589.27

1,047

1 5

4

3 2

C

586.60 B

587.89

1,307

DD1

597.58

DD2

588.22

DD4

592.92

DD3

582.35

W3

588.16

W4

586.12

W2

586.45

W1

584.72

SG1

588.26

7th Street

B

578.89

1,307

EXPLANATION

Open water

Stream

Illinois Beach State Park boundary

Primary direction of surface-water flow

Secondary component of surface-water flow

W1

584.72

Illinois State Geological Survey gage (B-H) and 

 well (1-18); identifier; water-level elevation, 

 in feet above North American Vertical Datum 

 of 1988; and average specific conductance, 

 in microsiemens per centimeter (in blue)

Culvert

Storm drain Surface-water measuring point; identifier; and 

 water-level elevation, in feet above North 

 American Vertical Datum of 1988
28 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Water-level elevations in the central part of the SBNP 

near gages W3 and DD2 were 1–3 ft higher than the waterlevel elevation at gage W2 in the eastern part of the wetland 

(table 7; appendix 1), indicating that surface water had the 

potential to flow from the central to the eastern parts of the 

SBNP throughout the period of investigation. The access road 

near the central part of the SBNP is partly on a ridge that is 

somewhat topographically elevated relative to the surrounding 

wetlands. The ridge and road appear to restrict flow between 

the central and eastern parts of the SBNP. During periods of 

higher water levels, parts of the access road were flooded, and 

west-to-east flow likely was substantial. During periods of 

lower water levels, flow between the central and eastern parts 

of the SBNP is largely blocked by the ridge and access road, 

and flow between the central and eastern parts of the SBNP 

likely is small (fig. 14). The large difference in water-level 

elevations between gages DD2/W3 and W2 likely is partly 

owing to the flow restriction created by the road/ridge (and 

previously mentioned infilled ditch across these features), 

which results in the buildup of water in the central part of the 

SBNP during low-water periods. 

The movement of water in the eastern part of the SBNP is 

partly controlled by the road on the eastern edge of the SBNP 

as well as the storm drain near gage W2 (fig. 14), which are 

alterations from the natural drainage. The elevation of the 

drain near gage W2 is about 586.1 ft. When water levels in 

the eastern part of the SBNP exceed this elevation (as happened during much of late May and early June 2007, much 

of August and early September 2007, and most of the period 

January–July 2008), water flows into the drain and out to Lake 

Michigan (table 7; appendix 1). When water levels are below 

this elevation (water depth at gage W2 less than about 2.8 

ft), surface water does not drain from the wetland but is lost 

to evapotranspiration and infiltration to groundwater. Water 

levels at gage W2 were less than 586.1 ft during most or all 

of June, July, September, October, November, and December 

2007.

Water-level elevations on the north side of the culvert 

beneath 7th Street were at least 0.50 ft higher at gage DD2 in 

the SBNP than on the south side at gage SG1 (fig. 14) in the 

NUIBSP for most of the investigation (table 7; appendix 1), 

indicating that this culvert, which partly was obstructed by 

sediment and debris, typically restricts surface-water flow 

from the SBNP to the NUIBSP. The exception to this period of 

restricted flow appears to have occurred during late April–June 

2008, when water-level elevations at gages DD2 and SG1 

differed by less than 0.10 ft (appendix 1) and more substantial 

flow through the culvert was likely. Aside from the culvert, 

7th Street itself eliminates the natural flow of surface water 

between the SBNP and the NUIBSP. 

Surface-water flow into the western part of the NUIBSP 

south of 7th Street begins as overland runoff and storm drainage coming off the bluff west of the railroad tracks (fig. 14). 

Water then flows through culverts beneath the railroad tracks 

(such as the 4-ft by 7-ft culvert monitored by gage DD4) into 

the wetlands and stream channels of the NUIBSP east of the 

railroad tracks, where is meets southward drainage from the 

culvert beneath 7th Street. 

Water in the stream channels and wetlands in the western and central parts of the NUIBSP flows to the eastern part 

of the NUIBSP and out to Lake Michigan through a culvert 

(diameter about 2.5 ft) at gage DD3. The elevation of the 

base of the culvert at gage DD3 is about 581.4 ft. When water 

levels at the culvert exceeded this elevation (much of late May 

and early June 2007, much of August 2007, most of the period 

from late-December 2007 to the end of measurements in 

June 2008), water from the NUIBSP had the potential to flow 

through the culvert into Lake Michigan (appendix 1). When 

water-level elevations were below this elevation (most or all 

of June, July, September, October, November, and December 

2007 and February 2008), water in the NUIBSP area did not 

drain from this part of the wetland but was lost to evapotranspiration or infiltration to groundwater.

Additional insight into the hydrology of the northern part 

of the study area was obtained by examining the timing of 

water-level changes in response to a precipitation event that 

occurred on June 8, 2007 (fig. 10). The storm was a short, isolated event (the nearest dates when more than trace amounts 

of precipitation was recorded were June 4 and 18) of moderate 

size (0.84 in.), and it produced a distinct rise in water levels at 

the gages in the SBNP and CPSNA. 

On Dead Dog Creek west of the SBNP, the water-level 

elevation at gage DD1 peaked at about 0600 hours Central 

Daylight Time (CDT) on June 8 and returned to pre-precipitation event water levels—a change of about 1.6 ft—several 

hours later (fig. 15). In the western and central parts of the 

SBNP the water-level rises at gages W3 and DD2 were nearly 

identical, indicating free flow of surface water within the 

central part of the SBNP. Water levels peaked on June 8 at 

about 1000 hours CDT and remained near this level for about 

1 day before water levels slowly began to decline. By June 17, 

water levels in these gages were approximately 0.3 ft above 

their pre-June 8 levels. The rise in water levels at gages W3 

and DD2 was about 1.0 ft. Water levels near the northern part 

of the SBNP at gage W1 peaked on June 8 at about 1400 hours 

CDT and slowly decreased to pre-June 8 water levels (difference of about 2.0 ft) on June 15. The response at gage W4 (not 

shown in the figure) in the central part of the NUIBSP to the 

precipitation was similar to the response in the central part of 

the SBNP at gage DD2. The water level at gage W4 peaked 

on June 9 at about 0400 hours CDT and remained at that level 

for about 4 days, then slowly decreased to pre-June 8 water 

levels on June 15. The change in water levels at gage W4 was 

about 1.15 ft. Finally, water levels in the western part of the 

SBNP at gage W2 peaked on June 9 at about 1200 hours CDT 

and remained near that level for about 4 days before slowly 

declining. The water level in this gage was approximately 

0.8 ft above its pre-June 8 level on June 17. The water-level 

response at this gage was about 1.5 ft. 
Surface-Water Hydrology 29

These data indicate that the water-level response to the 

June 8 rainfall was largest and quickest on the bluff at gage 

DD1 and in the swale at gage W1. These are the areas of the 

most channelized surface-water movement, with flow at gage 

DD1 draining into the wetlands in the center of the SBNP 

and flow in the swale at gage W1 draining to the ponds north 

of the SBNP and then into Lake Michigan. The water-level 

response (change in water level and duration of impact) to the 

June 8 precipitation was intermediate at gages W3 and DD2. 

These are relatively wide, flat areas with low to moderate 

water movement, where flow is to the north through the swale 

in the center of the SBNP and east toward gage W2 through 

the culvert beneath, and perhaps over, the access road in the 

east-central part of the SBNP. The water-level response to 

the June 8 precipitation at gage W2 was characterized by a 

large, somewhat delayed, rise in water level of relatively long 

duration as precipitation and surface-water inflow from the 

western part of the SBNP accumulated in the depressions in 

the eastern part of the SBNP. This area has the most restricted 

surface flow—bounded by the roads and dunes to the north, 

south, east, and west (fig. 6). Once collected in this area, water 

slowly drains to Lake Michigan via the storm drain in the 

northeastern corner of the SBNP (fig. 15) as well as evapotranspiration and discharge to groundwater. 

Hydroperiod

Water-level measurements at gages W1, W2, W3, and 

DD2 (table 8) in the SBNP during May 24, 2007–May 24, 

2008, indicate that water depths were greatest for the longest 

periods of time at gage W3 (depth typically exceeded 2.5 ft), 

at gage DD2 (depth typically exceeded 1 ft), and in the wetlands near the storm drain control structure at gage W2 (depth 

typically exceeded 2 ft). These gages had standing water (or 

ice) for the entire period of investigation. Water depth and 

duration of inundation were lower at gage W1, where water 

depth typically exceeded 1 ft, but the gage was nearly dry for a 

1 to 2 week period. 

Gage W3 is in a man-made pond (fig. 14) where water 

levels are atypically deep for this area. The depth of water is 

greater and the period of inundation is longer at this gage relative to natural conditions because of the depth of the pond as 

well as the possible buildup of water in the western part of the 

SBNP owing to flow restrictions associated with 7th Street and 

the access road in the central part of SBNP. 

Gage W1 is in a swale near relatively undisturbed parts 

of the wetland complex to the west. Ditches to the east of the 

gage likely would facilitate water drainage (fig. 14). 

Gage DD2 is in a man-made drainage ditch near the 

upstream side of the partly obstructed culvert beneath 

7th Street (fig. 14). The depth of water is greater and the 

period of inundation likely is longer at this gage relative to 

natural conditions because of the flow restriction created by 

7th Street and the blocked culvert. 

Gage W2 is in a part of the wetland complex that 

is somewhat isolated from the overall drainage by 

the surrounding roads (figs. 6 and 14), which create 

topographically elevated areas that restrict surface-water 

drainage. Gage W2 also is near a drainage control structure. 

-0.5

0

0.5

1

1.5

2

2.5

6/7/2007

0:00

6/9/2007

0:00

6/11/2007

0:00

6/13/2007

0:00

6/15/2007

0:00

6/17/2007

0:00

DATE AND TIME

WATER-LEVEL CHANGE, IN FEET

W1

W2

W3

DD2

DD1

Gage

Figure 15. Hydrograph showing water-level responses to June 8, 2008, rainfall, Spring Bluff Nature Preserve, 

Winthrop Harbor, Illinois. 
30 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

The combination of surrounding landscape and drainage 

control structures restricts the amount of surface drainage from 

the eastern part of the SBNP, as well as the stage at which 

drainage may occur. For these reasons, the depth of water is 

greater and the period of inundation likely is longer at gage 

W2 relative to natural conditions. Data indicate that surface 

water flowed from the wetlands to Lake Michigan for about 

154 days at gage W2 during the period from May 24, 2007, to 

May 24, 2008, primarily during late May and early June 2007, 

much of August and early September 2007, and most of the 

period January–May 2008. 

Hydroperiods at gages SG1, W4 and DD3 in the NUIBSP 

during May 24, 2007–May 24, 2008, show that water depths 

were greatest (depth typically exceeded 1.5 ft) and water was 

present for the longest period of time (the entire period of 

monitoring) at gage SG1, shortest at gage DD3 (area was dry 

for nearly half the data-collection period), and intermediate 

length at gage W4 (depth typically exceeded 1 ft, but area 

could be nearly dry for periods of weeks) (table 8). 

Gage W4 is in a wetland swale next to an access road in 

a part of the wetland complex (the NUIBSP) that appears to 

be well drained by ditches (figs. 6 and 14) and that typically is 

isolated from substantial sources of inflowing surface water. 

The depth of water and period of inundation at this gage likely 

are lower than would be typical under natural conditions. 

Surface-water conditions in the swale appear to be typical of 

the wetlands in this part of the study area.

Gage DD3 is in a man-made drainage ditch at a culvert 

in the eastern part of the wetland complex near the point of 

discharge to Lake Michigan. The depth of water and period of 

inundation at this gage appear to be greater relative to natural 

conditions because of the effects of the ditch and the culvert, 

but they may be decreased somewhat by the overall lack of 

flow from the SBNP into the NUIBSP because of the flow 

obstruction at 7th Street and its culvert. Hydroperiod data 

indicate that the potential for surface-water discharge from 

these wetlands to Lake Michigan existed for about 166 days 

at gage DD3, for the period May 24, 2007–May 24, 2008. The 

channel from gage DD3 to the lake may have been blocked by 

the buildup of sand at the lakeshore during some of this time. 

This location is immediately south (downdrift) of a beachnourishment sand pile. 

Table 8. Hydroperiod, in days, at selected gages in the wetlands in the vicinity of the Spring Bluff Nature Preserve, Chiwaukee Prairie 

State Natural Area, and Illinois Beach State Park, near Winthrop Harbor and Waukegan, Illinois, May 24, 2007–May 24, 2008. Locations 

of staff gages are shown in figures 2–4. 

[NAVD 88, North American Vertical Datum of 1988; na, not applicable; *, less than 0.10 foot of water at gage during some periods]

Elevation 

(feet above 

NAVD 88)

Number of days water level exceeded elevation (hydroperiod) at indicated gage

W1 W2 W3 DD2 SG1 W4 DD3 DR2

590.0 0 0 0 0 0 0 0 0

589.5 0 0 0 2 0 0 0 0

589.0 0 0 33 23 0 0 0 0

588.5 0 0 145 172 4 0 0 0

588.0 0 0 330 329 160 0 0 0

587.5 0 0 341 343 249 0 0 0

587.0 3 15 366 366 329 0 0 0

586.5 15 47 366 na 340 73 0 0

586.0 72 154 366 na 366 175 0 0

585.5 111 214 366 na na 327 0 0

585.0 186 266 na na na 341 0 55

584.5 276 303 na na na 366 0 325

584.0 354 325 na na na na 0 366

583.5 *366 336 na na na na 0 366

583.0 na *366 na na na na 0 na

582.5 na na na na na na 54 na

582.0 na na na na na na 158 na

581.5 na na na na na na 166 na

Below land surface 0 0 0 0 0 0 200 0

Land-surface elevation 

at gage, in feet above 

NAVD 88

583.50 583.35 585.50 586.93 585.84 584.45 581.40 583.50
Surface-Water Hydrology 31

Surface-Water Discharge 

Discharge was measured (or visually estimated when 

flow was too low to be quantified or water levels were too low 

for a measurement) at gages DD1, DD2, DD3, DD4, SG1, 

W1, DR1, DR2, and DR3 during the periodic water-quality 

sampling events (table 9). As a consequence, these measurements were collected during random weather conditions and 

therefore are not representative of the total range of discharge 

(particularly the higher values) during the investigation.

Discharges typically were greatest at gages DD1 and 

DR1 because their position on the bluffs west of the coastal 

complex facilitates water movement, and they drain fairly 

large watersheds. Discharge in the bluff area at gage DD4 

typically was absent or less than 0.01 ft3/s. Gage DD4 drains a 

small watershed that receives discharge primarily from stormwater. Discharge at gages DD1, DR1, and DD4 was greatest 

during April and May 2008, most likely because of the higher 

volume of runoff from precipitation events during this time, 

and least during July 2007 owing to seasonally low runoff 

(table 9). This pattern is typical of annual stream discharge 

cycles in northern Illinois (Hensel, 1992).

Discharge at the gages in the ditches and swales in the 

wetland areas (gages W1, DD2, DR2, SG1) typically was estimated to be at or near zero (table 9) because the topographic 

gradient in the wetland complex is low and the area for flow 

is large. Measurable discharge was present at gages W1 and 

DR2 during the spring months, when water levels and runoff 

were highest, but was not detected during most of the periods 

when water levels were lower. It is probable that measurable 

amounts of discharge passed gages W1 and DR2 after precipitation events, but these events were not monitored. Flow 

also was not observed through the culvert at 7th Street at any 

time during the investigation, most likely because this culvert 

was partially blocked by sediment or debris. It is apparent that 

7th Street restricts surface-water flow between SBNP and the 

NUIBSP and that these areas are partly isolated from each 

other (from a surface-water perspective) except during periods 

when water levels are above the restrictions in the culvert. 

Discharge at gages DD3 and W2, located near the outlets 

to Lake Michigan, was affected by the water-level elevation in 

the wetlands. Discharge of surface water from the wetlands at 

the NUIBSP and eastern part of the SBNP into Lake Michigan 

occurred only during periods when water levels were above 

threshold altitudes at these gages, such as occurred after the 

precipitation events in August 2007, during the spring of 

2007, and the spring and early summer of 2008. Precipitation 

amounts were unusually high during parts of the summers of 

2007 and 2008 (table 4). Surface-water discharge from these 

wetlands to Lake Michigan likely is minimal or absent during 

substantial parts of a typical year, including most of a typical 

summer. 

The presence of discharge from the SUIBSP to Lake 

Michigan via the Dead River was affected by whether or not a 

sandbar was blocking the outlet to Lake Michigan (gage DR3, 

table 9). When a sandbar was present, there was no discharge 

at gage DR3. When the sandbar was eroded by waves or overtopped by high water levels in the Dead River, discharge could 

be substantial. The presence or absence of discharge at gage 

DR3 was sometimes noted during the water-level measurements (appendix 1). These observations, combined with the 

hydrograph for gage DR3 (fig. 12), indicate that discharge 

from the Dead River to Lake Michigan was sporadic but 

occurred during high-water periods at the end of May through 

much of June and mid-July 2007, probably occurred after the 

precipitation events during August 2007, and occurred during 

much of mid-December 2007 through May 2008. Discharge 

was not observed during the latter part of July 2007 and from 

October through mid-December 2007. 

Table 9. Streamflow measurements at selected gages in the vicinity of the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, near Winthrop 

Harbor and Waukegan, Illinois, May 24, 2007–May 13, 2008. Locations of gages are shown in 

figures 2–4. 

[--, measurement not made; <, less than; e, estimated, flow rate too low to be quantified; flow, flow observed but was 

not quantified]

Staff gage Flow, in cubic feet per second

05/24/07 05/25/07 06/27/07 07/30/07 04/02/08 05/13/08

DD1 -- 0.26 0.18 0.01 6.4 0.59

DD2 <0.01 e -- <.01 e <.01 e <.01 e <.01 e

DD3 <.01 e -- 0 e dry 2.89 .003

DD4 <.01 e -- <.01 e dry .22 .1 e

SG1 <.01 e -- <.01 e <.01 e <.01 e <.01 e

W1 .19 -- 0 e 0 e 4.62 .17

W2 -- -- -- -- flow flow

DR1 -- .71 1.08 .05 14.7 .94

DR2 -- 0 e 0 e 0 e 10.8 0 e

DR3 -- .00 1.58 0 e 63.4 6.0
32 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Previous investigators have noted that sandbar formation 

occasionally prevented discharge to Lake Michigan via the 

ditch in the NUIBSP at gage DD3 (Visocky, 1976; Kubillus, 

1994). However, discharge restriction owing to sandbars was 

not observed when measurements were made during the current investigation.

Implications of Surface-Water Hydrology

Characterization of presettlement surface-water hydrology is not possible given the lack of presettlement data in 

this area. However, agricultural and urban land use within a 

watershed typically increase overland runoff of precipitation 

in comparison to presettlement conditions (U.S. Department of 

Agriculture, 1996; Konrad, 2003; Konrad and Booth, 2005). It 

is probable, therefore, that the amount of surface-water inflow 

to the wetland complex has been greater in recent years than 

in the past and is likely contributing to the apparently higher 

water levels in parts of the wetland complex.

In the SUIBSP, the wetland complex receives surface 

water from direct precipitation and inflow from Bull Creek, a 

perennial stream draining a watershed of more than 5.5 mi2. 

As a consequence, the SUIBSP receives a continuous input 

of surface water. The inflow is offset by evapotranspiration, 

discharge to groundwater, and intermittent outflow of the Dead 

River to Lake Michigan. The road through the SUIBSP likely 

reduces the exchange of water between Bull Creek and the 

Dead River with the surrounding wetlands, but the numerous open culverts in the area (fig. 4) partly counteract this 

restriction.

In the northern part of the study area, the SBNP and 

CPSNA receive surface water from direct precipitation and 

inflow from Dead Dog Creek, a perennial stream draining 

a watershed of about 1.5 mi2. The SBNP and CPSNA also 

receive smaller amounts of water from smaller perennial and 

intermittent drainages north of Dead Dog Creek. As a consequence, this part of the wetland complex receives a continuous input of surface water. This inflow typically is offset by 

the removal of water via drainage to the surface-water outlet 

near the state line and to a lesser extent the culvert beneath 

7th Street, flow into the storm drain near gage W2, discharge 

to groundwater, and evapotranspiration. The roads, obstructed 

culverts, berms, and ditches at the SBNP restrict the movement of water between the western, central, and eastern parts 

of the wetland complex in this area as well as between the 

SBNP and the NUIBSP (this restriction is minimized during 

periods of high water). This alteration of the presettlement 

flow conditions results in the accumulation of water in the 

SBNP, especially near the eastern part and points of inflow. 

Water collects in the eastern part of the SBNP because it is 

a topographically low area surrounded by topographically 

elevated areas associated with roadways and dunes, and it typically has only one small, intermittent outlet for surface-water 

discharge, which is at a higher elevation that the surrounding 

wetland bottom. These changes in the topography and hydrology likely have resulted in longer periods of higher water 

levels in the eastern part of the SBNP relative to presettlement 

conditions. The effect of these alterations on the hydroperiod 

in the central and western parts of the SBNP is less clear, but 

it appears that water levels may be elevated for an indeterminate—but longer—period of time, resulting from the higher 

amounts of inflow and disruptions to water movement caused 

by the roads and obstructed culverts in the central, northeastern, and southern parts of the SBNP.

In the northern part of the study area, the NUIBSP 

receives intermittent surface-water inflow from a small 

(0.4 mi2) drainage during storms and snowmelt, intermittent 

inflow from the drainage ditch under the culvert at 7th Street, 

and input directly from precipitation. As a consequence, 

this part of the wetland complex receives smaller amounts 

of surface water relative to the rest of the study area. Water 

is removed from this area via intermittent drainage to Lake 

Michigan near gage DD3, evapotranspiration, and discharge 

to groundwater. Roads, obstructed culverts, berms, and ditches 

at the NUIBSP appear to restrict surface-water flow into, 

and increase the drainage out of, the NUIBSP in comparison 

to presettlement conditions. As a result, water levels in the 

NUIBSP likely are lower, and are elevated for shorter periods 

of time, than would be typical of natural conditions.

Groundwater Hydrology

Previous investigators have determined that groundwater 

and the surface water in the creeks and wetlands of the study 

area interact in a spatially and temporally complex manner 

(Visocky, 1976; Kubillus, 1994). Detailed investigation of 

groundwater hydrology and surface-water groundwater interactions is beyond the scope of this investigation. However, 

water-level data from the wells in the study area were used to 

measure hydroperiods in various plant communities to help 

determine if hydraulic alterations could be related to changes 

in the plant communities.
Groundwater Hydrology 33

Groundwater Levels Through Time

Trends in groundwater levels are similar to those of 

surface water, indicating they were responding to the same 

hydraulic influences. Generally, groundwater levels were low 

in July 2007 as a result of decreased availability of infiltrating 

water and increased evapotranspiration in summer (Hensel, 

1992), but levels increased greatly in August 2007 in response 

to record amounts of rainfall (fig. 16). Groundwater declined 

to more typical seasonal levels by October 2007 and continued 

to decline through late fall 2007. Water levels increased from 

late fall 2007 through late spring 2008 in response to recharge 

from rainfall, snowmelt, and surface water and decreased 

evapotranspiration. Water levels again declined in late spring 

2008 through the end of summer, as evapotranspiration 

increased and the availability of surface water and precipitation for recharge decreased. Trends in groundwater levels 

showed similarities between wells in different types of plant 

communities even though ranges of levels relative to land 

surface differed considerably among the various communities, 

as discussed in the next section.

DATE

July Aug Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept.

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

20

21

22

EXPLANATION

2007 2008

Green symbols are from

emergent marshes, black

symbols are from sedge

meadows, pink symbols are

from wet prairies, blue

symbols are from wet-mesic

prairie, and red symbols are

from mesic prairies.

Panne (19) is shown on

figure 17.

Land surface

3.00

2.00

1.00

0.00

-1.00

-2.00

-3.00

-4.00

Feet above land surface Feet below land surface

DEPTH TO GROUNDWATER ABOVE AND BELOW LAND 

SURFACE AT EACH MONITORING WELL, IN FEET

Figure 16. Depth to groundwater in monitoring wells, Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and Illinois 

Beach State Park, near Winthrop Harbor and Waukegan, Illinois, July 2007–August 2008. 
34 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Hydroperiods Associated With Different Plant 

Communities

Monitoring wells were installed in each of the plant community types and water levels in each community type were 

grouped (fig. 16). Depth to groundwater during the period of 

investigation showed distinct differences between the wells 

located in the various plant communities. Depth to water in 

wells from each community type are similar and have relatively little overlap with water levels in wells in other plant 

community types. 

Wells in emergent marsh wetlands, the wettest communities found in the study area, had water levels that generally 

remained near or above land surface for most or all of the year 

(positive values for depth to water in figure 16 indicate water 

levels above land surface). Water levels in the emergent marsh 

areas averaged about 0.5 ft above land surface but were as 

much as about 2.5 ft above land surface. 

Water levels in sedge meadows were as much as 0.75 ft 

above land surface for several months in late fall through early 

summer but were 0.5 to 2 ft below land surface in late summer 

and early fall. This pattern is conducive to sedges, which need 

dry periods in summer for vegetative propagation. 

Water levels in the driest wetland community investigated, wet prairie, averaged about 0.5 ft below land surface. 

However, water levels in the wet prairie were near, or as 

much as 0.5 ft above, land surface for several weeks in the 

late winter and early spring before decreasing to about 0.5 to 

1.5 ft below land surface during summer. 

Water levels in the nonwetland wet-mesic and mesic 

prairie communities typically were below land surface during the spring and decreased to more than 2.5 ft below land 

surface for much of the year. Average water levels in these 

communities were about 2 ft below land surface. Water levels 

in the wet-mesic prairie near well 11 were above land surface during the winter and spring 2008, possibly because of 

wetter than normal weather conditions or the well’s location 

adjacent to a swale that receives water from offsite. The presence of standing water in an area of wet-mesic prairie may 

indicate a change in the hydrology of this area from its natural 

conditions.

The water levels from all of the wells in each type of 

plant community during each measurement date were used 

to determine the average water level through time for each 

plant community type (fig. 17). As expected, the trends in 

the average depth to water for the various plant communities were similar those determined from the individual wells. 

Emergent marsh (n=7)

Sedge meadow (n=2)

Wet prairie (n=5)

Wet-mesic prairie (n=2)

Mesic prairie (n=5)

Panne (n=1)

DATE

July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept.

2007 2008

Land surface

Feet above land surface Feet below land surface

2.00

1.50

1.00

0.50

0.00

-0.50

-1.00

-1.50

-2.00

-2.50

-3.00

-3.50

DEPTH TO GROUNDWATER ABOVE AND BELOW LAND SURFACE, IN FEET

Figure 17. Average depth 

to groundwater in each 

type of wetland community, 

Spring Bluff Nature Preserve, 

Chiwaukee Prairie State 

Natural Area, and Illinois 

Beach State Park, near 

Winthrop Harbor and 

Waukegan, Illinois, July 2007–

August 2008. 
Groundwater Hydrology 35

Average water levels in emergent marshes and sedge meadows were above land surface for substantial periods of time. 

Average water levels in mesic prairie were always below land 

surface. Average water levels in wet prairies and wet-mesic 

prairies were typically below land surface but were above land 

surface for short periods. The only well installed in a panne 

had standing water levels that were similar to those of a sedge 

meadow during the spring of 2008, but water levels were 

similar to those of mesic prairie during the rest of the period of 

measurement. 

Given the unusually wet conditions in August 2007 

(table 4), water levels in late summer and fall 2007 may have 

been atypically high for these communities. Water levels in 

August 2008 are likely to be more typical. Also, precipitation 

in much of 2008 was atypically high, likely increasing water 

levels in these communities and prolonging the inundated 

periods longer into summer than normal.

Relation of Hydroperiod to Invasive Plant 

Species

Analysis indicates that hydroperiods of wetland communities containing invasive plants (for example, Typha spp. 

and Phragmites australis) were different from those at wetland 

communities where invasive plants were absent or in low 

abundance (table 10). Phragmites australis had an importance 

value greater than 10 at 2 of the 7 sampling locations in the 

emergent marsh wetlands but were only present (importance 

value 4.4) at 1 of the 15 sampling locations associated with all 

other wetland types. Typha spp. were abundant in emergent 

marsh wetlands (average importance value 19.2) but were 

much less common or nonexistent in other wetland types. The 

only emergent wetland sampling location where Typha spp. 

were not present was well 18 in the CPSNA (fig. 3). The 

hydroperiod at this emergent wetland is not obviously different from that of other emergent marshes (compare in fig. 16). 

Given that Typha spp. are found in the same interdunal swale 

wetland only a few hundred feet away from well 18, it may 

be that this location will be colonized by Typha spp. at some 

point in the near future. The current absence of Typha spp. is 

more likely related to a lag time between hydrologic alteration and the colonization of all available habitat rather than an 

absence of alteration.

Table 10. Characteristics of vegetation, hydrology, and specific conductance sampled, including summaries by plant community, 

adjacent to wells 1–22 at the Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, 

near Winthrop Harbor and Waukegan, Illinois. Locations of wells are shown in figures 2–4. 

[SQ, square; SBNP, Spring Bluff Nature Preserve; CPSNA, Chiwaukee Prairie State Natural Area; SUIBSP, Southern Unit Illinois Beach State Park]

Well 

number Location

Mean 

coefficient of 

conservativism

Native mean 

coefficient of 

conservativism

Species 

richness 

index 

(SQ root)

Native 

species 

richness 

index 

(SQ root)

Mean 

vegetation 

wetness

Average 

richness 

per 10.75 

square feet

1 SBNP 4.0 5.5 2.2 0.4 -5.0 1.2

2 SBNP 3.7 4.4 82.7 63.0 .4 14.6

3 SBNP 4.9 5.3 18.2 16.2 -4.9 5.2

4 SBNP 3.9 4.8 66.8 42.9 1.8 11.6

5 SBNP 1.0 0 1.0 .0 -5.0 1

6 SBNP 5.5 5.7 79.4 77.4 -2.8 14.5

7 SBNP 3.3 3.9 15.0 8.5 -4.2 4.8

8 SBNP 4.7 5.3 83.9 73.9 -1.0 14.4

9 SBNP 2.8 5 7.4 2.2 -4.0 3

10 SBNP 4.2 4.6 30.9 25.6 -2.6 6.8

11 SBNP 4.2 5 53.1 39.0 -1.4 10.6

12 SBNP 3.3 4.5 2.8 .9 -4.3 1.6

13 CPSNA 5.2 5.8 69.7 62.9 -.4 11.6

14 CPSNA 4.9 5.2 27.6 26.3 -3.8 6.5

15 CPSNA 4.4 5 80.9 70.7 .1 13.1

16 CPSNA 6.0 6.4 32.7 35.2 -3.6 8

17 CPSNA 4.5 5.6 59.4 40.8 .9 10.5

18 CPSNA 5.0 5 9.6 9.6 -5.0 3.6

19 NUIBSP 5.6 6 22.7 21.5 -3.4 5.5

20 SUIBSP 6.1 6.5 82.1 78.2 -3.5 13.9

21 SUIBSP 6.8 8.1 20.4 13.9 -5.0 5.9

22 SUIBSP 6.2 6.8 62.7 52.9 -3.7 10.8
36 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Table 10. Characteristics of vegetation, hydrology, and specific conductance sampled, including summaries by plant community, 

adjacent to wells 1–22 at the Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, 

near Winthrop Harbor and Waukegan, Illinois. Locations of wells are shown in figures 2–4. —Continued

[SQ, square; SBNP, Spring Bluff Nature Preserve; CPSNA, Chiwaukee Prairie State Natural Area; SUIBSP, Southern Unit Illinois Beach State Park]

Well 

number

Species 

richness 

per well

Native 

species 

richness 

per well

Relative 

importance 

value 

Typha spp. 

per well

Relative 

importance 

value 

Phragmites 

australis

per well

Average 

density of 

Typha spp. 

per 10.75 

square feet

Average 

density of 

Phragmites 

australis

per 10.75 

square feet

1 3 2 35.6 0.0 10 0

2 32 27 .0 .0 0 0

3 12 11 3.6 .0 1 0

4 33 27 .0 .0 0 0

5 1 0 34.2 .0 8 0

6 30 29 .0 .0 0 0

7 10 8 16.6 12.1 4 4

8 34 30 .0 .0 0 0

9 6 3 23.5 10.9 10 4

10 21 19 .0 4.4 0 1

11 25 21 1.2 .0 1 0

12 3 2 20.9 .0 3 0

13 36 32 .0 .0 0 0

14 18 17 .0 .0 0 0

15 38 34 .0 .0 0 0

16 21 20 .0 .0 0 0

17 32 26 .0 .0 0 0

18 7 7 .0 .0 0 0

19 17 16 .0 .0 0 0

20 35 33 .0 .0 0 0

21 12 10 8.8 .0 3 0

22 34 31 6.1 .0 5 0

Well 

number

Community 

type

Total days of 

inundation

Growing 

season days 

of inundation

Average 

depth to 

water 

(feet above + 

or below -

land surface)

Average 

specific 

conductance 

(microsiemens per 

centimter)

1 Emergent 

Marsh

335 219 -0.204 1,307

2 Mesic Prairie 0 0 6.80

3 Emergent 

marsh

293 214 -.172

4 Mesic Prairie 0 0 .736

5 Emergent 

Marsh

232 172 -.105

6 Wet Prairie 0 0 .246

7 Emergent 

Marsh

207 122 .025 1,047

8 Mesic Wet 

Prairie

0 0 .263

9 Emergent 

Marsh

329 195 -.078
Groundwater Hydrology 37

Table 10. Characteristics of vegetation, hydrology, and specific conductance sampled, including summaries by plant community, 

adjacent to wells 1–22 at the Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, 

near Winthrop Harbor and Waukegan, Illinois. Locations of wells are shown in figures 2–4. —Continued

[SQ, square; SBNP, Spring Bluff Nature Preserve; CPSNA, Chiwaukee Prairie State Natural Area; SUIBSP, Southern Unit Illinois Beach State Park]

Well 

number

Community 

type

Total days of 

inundation

Growing 

season days 

of inundation

Average 

depth to 

water 

(feet above + 

or below -

land surface)

Average 

specific 

conductance 

(microsiemens per 

centimter)

10 Wet Prairie 0 0 0.130

11 Mesic Wet 

Prairie

98 32 .221

12 Emergent 

Marsh

340 223 -.500 1,856

13 Mesic Prairie 0 0 .405

14 Sedge 

Meadow

262 137 -.007

15 Mesic Prairie 0 0 .511

16 Wet Prairie 124 32 .108

17 Mesic Prairie 0 0 .625

18 Emergent 

Marsh

287 185 -.168 716

19 Panne 89 66 .310

20 Wet Prairie 12 0 .087

21 Sedge 

Meadow

337 217 -.052 1,234

22 Wet Prairie 198 128 -.024

Summary 

of selected 

information 

by plant 

community

Well

Average 

depth to 

water 

(feet above +

or below -

land surface)

Importance 

value 

Typha spp.

Importance 

value 

Phragmites 

australis

Native 

species 

richness 

index

Total 

species 

richness 

index

Total 

days of 

inundation

Growing 

season 

days of 

inundation

Panne IBSP 19s -1.02 0 0 21.52 17 89 66

Mesic Prairie SBNP 2 -2.24 0 0 62.98 32 0 0

SBNP 4 -2.42 0 0 42.87 33 0 0

CHI 13s -1.33 0 0 62.90 36 0 0

CHI 15s -1.68 0 0 70.67 38 0 0

CHI 17s -2.05 0 0 40.79 32 0 0

Average -1.94 0 0 56.04 34.2 0 0

Mesic Wet 

Prairie

SBNP 8s -.86 0 0 73.94 34 0 0

SBNP 11s -.72 1.2 0 38.95 25 98 32

Average -.79 .6 0 56.45 29.5 49 16

Wet Prairie SBNP 6s -.81 0 0 77.44 30 0 0

SBNP 10s -.43 0 4.4 25.63 21 0 0

CHI 16s -.36 0 0 35.24 21 124 32

IBSP 20s -.28 0 0 78.24 35 12 0

IBSP 22s .08 6.1 0 52.89 34 242 128

Average -.36 1.22 .88 53.89 28.2 76 32
38 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Table 10. Characteristics of vegetation, hydrology, and specific conductance sampled, including summaries by plant community, 

adjacent to wells 1–22 at the Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, 

near Winthrop Harbor and Waukegan, Illinois. Locations of wells are shown in figures 2–4. —Continued

[SQ, square; SBNP, Spring Bluff Nature Preserve; CPSNA, Chiwaukee Prairie State Natural Area; SUIBSP, Southern Unit Illinois Beach State Park]

Summary 

of selected 

information 

by plant 

community

Well

Average 

depth to 

water 

(feet above + 

or below - 

land surface)

Importance 

value 

Typha spp.

Importance 

value 

Phragmites 

australis

Native 

species 

richness 

index

Total 

species 

richness 

index

Total 

days of 

inundation

Growing 

season 

days of 

inundation

Sedge 

Meadow

CHI 14s 0.02 0 0 26.31 18 282 137

IBSP 21s .17 8.8 0 13.85 12 381 217

Average .10 4.4 0 20.08 15 332 177

Emergent 

Marsh

SBNP 1s .67 35.6 0 .35 3 382 219

SBNP 3s .57 3.6 0 16.19 12 338 214

SBNP 5s .35 34.2 0 .00 10 276 172

SBNP 7s -.08 16.6 12.1 8.49 10 237 122

SBNP 9s .26 23.5 10.9 2.17 6 359 195

SBNP 12s 1.64 20.9 0 .85 3 387 223

CHI 18s .55 0 0 9.58 7 319 185

Average .56 19.2 3.29 5.38 7.29 328

Surface-Water Quality

Surface-water quality data consist of discrete measurements of field parameters, nutrients, chloride, and sediment 

collected during the periodic sampling events; continuous 

measurements of field parameters at selected locations; and 

intensive sediment sampling during storm events.

Field Parameters 

Discrete measurements of temperature, dissolved oxygen, 

pH, and specific conductance were made in the field during 

each of the periodic water sampling events because these 

parameters are somewhat unstable and may change during 

transport of bottled samples to the laboratory. Analysis and 

interpretation of field parameters collected during the periodic 

sampling events is limited by the lack of data from all possible sites, owing to battery problems with the multiparameter 

instrument. However, patterns in values of many of the field 

parameters (not only discrete measurements collected during 

the periodic sampling events but also the continuous measurements collected from the dataloggers) provided insight into the 

chemistry of the study area.

Temperature

Water temperature is an important variable affecting 

many stream and wetland processes, such as the decomposition of organic matter (Webster and others, 1995) and 

the development of aquatic organisms (Sweeney, 1984; 

Allan, 1995). Water temperature affects the type of habitat and 

the organisms that can survive within the ecosystem. 

As expected, water temperatures measured during periodic sampling varied with atmospheric temperature. Measured 

temperatures were highest during the summer months (about 

20–24°C during June and August 2007) and lowest during 

the late fall (about 1–4°C in November 2007) (table 11). The 

intermittent presence of ice at all of the measurement stations 

during winter, when discrete temperature measurements were 

not made, indicates surface-water temperatures were near 0°C 

during much of the winter. 

Water temperatures in the study area varied by as much 

as 8.5°C between measurement locations during any individual periodic sampling event. Spatial differences in temperature 

during individual sampling events are primarily owing to variations in air temperature and the intensity of solar radiation at 

the time and place of the measurements and perhaps variations 

in the depth of water and amount of groundwater discharge. 

Continuous temperature measurements showed the 

expected cooling during winter and warming during summer 

(fig. 18). However, the water in the wetlands at gages W3 and 

12 did not freeze, probably because of the amount of standing 

surface water or the presence of relatively warm groundwater 

discharge. The data also show substantial warming events during early to mid-January, when runoff and snowmelt may have 

occurred. The large magnitude of the change in surface-water 

temperature at gages 7 and 18 relative to other sites is related 

to the smaller amount of standing water at these gages being 

more affected by the diurnal changes in temperature, which 

heated and cooled the surface water at the gages. 
Surface-Water Quality 39

Table 11. Field-parameter measurements in surface water at gages in the vicinity of the Spring Bluff Nature Preserve, 

Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, near Winthrop Harbor and Waukegan, Illinois, May 31, 2007–

May 13, 2008. Locations of gages are shown in figures 2–4. —Continued

[--, measurement not made]

Staff 

gage

05/31/2007 06/27/2007

Temperature 

(degrees 

Celsius)

Dissolved 

oxygen 

(percent 

saturation)

pH 

(standard 

units)

Specific 

conductance 

(microsiemens per 

centimeter)

Temperature 

(degrees 

Celsius)

Dissolved 

oxygen 

(percent 

saturation)

pH 

(standard 

units)

Specific 

conductance 

(microsiemens per 

centimeter)

DD1 17.7 89.05 7.67 1,165 20.2 78.69 8.09 1,155

DD3 -- -- -- -- -- -- -- --

DD4 -- -- -- -- 20.1 53.9 7.54 1,611

W1 -- -- -- -- -- -- -- --

W3 20.7 27.2 7.22 1,098 24.4 33.77 7.35 1,070

W4 -- -- -- -- 18.2 42 6.89 1,248

DR1 -- -- -- -- -- -- -- --

DR2 -- -- -- -- -- -- -- --

DR3 -- -- -- -- -- -- -- --

Staff 

gage

08/29/2007 09/18/2007

Temperature 

(degrees 

Celsius)

Dissolved 

oxygen 

(percent 

saturation)

pH 

(standard 

units)

Specific 

conductance 

(microsiemens per 

centimeter)

Temperature 

(degrees 

Celsius)

Dissolved 

oxygen 

(percent 

saturation)

pH 

(standard 

units)

Specific 

conductance 

(microsiemens per 

centimeter)

DD1 20.7 91 7.37 1,310 15.9 92.9 8.04 1,179

DD2 -- -- -- -- 15.9 41.15 7.58 1,002

DD3 20.0 52.8 7.18 1,253 -- -- -- --

DD4 -- -- -- -- 15.9 25.42 7.73 1,369

SG1 -- -- -- -- 18.2 23.89 7.41 957

W1 21.2 38.23 7.46 1,079 14.8 23.43 7.32 1,080

W2 -- -- -- -- 14.1 48.71 7.47 664

W3 24.5 72.34 7.51 1,265 16.2 64.49 7.65 1,122

W4 18.1 19.52 7.06 1,720 13.9 21.82 7.21 1,125

DR1 21.5 93.68 7.97 1,762 15.8 90.37 7.73 1,531

DR2 22.2 28.09 7.84 1,428 14.5 29.06 6.54 1,139

DR3 25.2 143.7 8.2 1,178 17.6 101.31 7.14 833

Staff 

gage

11/27/2007 04/02/2008

Temperature 

(degrees 

Celsius)

Dissolved 

oxygen 

(percent 

saturation)

pH 

(standard 

units)

Specific 

conductance 

(microsiemens per 

centimeter)

Temperature 

(degrees 

Celsius)

Dissolved 

oxygen 

(percent 

saturation)

pH 

(standard 

units)

Specific 

conductance 

(microsiemens per 

centimeter)

DD1 1.9 85.6 7.63 1,178 4.2 97.2 7.81 1,089

DD2 1.1 33.2 6.76 955 -- -- -- --

DD3 -- -- -- -- 4.7 85.6 7.82 974

DD4 3.9 111.4 7.66 1,404 8.6 96.1 7.97 2,406
40 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Table 11. Field-parameter measurements in surface water at gages in the vicinity of the Spring Bluff Nature Preserve, 

Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, near Winthrop Harbor and Waukegan, Illinois, May 31, 2007–

May 13, 2008. Locations of gages are shown in figures 2–4. —Continued

[--, measurement not made]

Staff 

gage

11/27/2007 04/02/2008

Temperature 

(degrees 

Celsius)

Dissolved 

oxygen 

(percent 

saturation)

pH 

(standard 

units)

Specific 

conductance 

(microsiemens per 

centimeter)

Temperature 

(degrees 

Celsius)

Dissolved 

oxygen 

(percent 

saturation)

pH 

(standard 

units)

Specific 

conductance 

(microsiemens per 

centimeter)

W1 4.2 50.6 7.05 933 10.3 94.2 7.96 863

W2 -- -- -- -- -- -- -- --

W3 3.8 79.2 6.51 1,144 9.2 84.5 7.18 1,157

W4 3.0 40.2 6.76 955 3.8 64.0 7.79 980

DR1 2.4 84.3 7.89 1,257 8.0 96.1 8.21 1,419

DR2 3.5 31.5 7.77 1,072 5.9 88.5 7.91 1,216

DR3 2.1 101.8 8.36 860 7.4 95.3 7.35 978

Staff 

gage

05/13/2008

Temperature 

(degrees 

Celsius)

Dissolved 

oxygen 

(percent 

saturation)

pH 

(standard 

units)

Specific 

conductance 

(microsiemens per 

centimeter)

DD1 10.6 99.4 6.97 1,021

DD2 14.5 95.4 8.05 960

DD3 12.3 62.5 7.59 882

DD4 11.9 78.5 7.47 1,819

SG1 15.8 96.1 8.07 1,438

W1 -- -- -- --

W2 13.3 38.0 7.55 913

W3 19.1 86.5 8.41 1,045

W4 9.8 52.9 7.55 1,069

DR1 14.8 117.0 8.41 1,367

DR2 -- -- -- --

DR3 17.5 -- -- --
Surface-Water Quality 41

Dissolved Oxygen

Dissolved oxygen is essential to aerobic respiration, 

and many chemical and biological reactions depend on the 

presence of oxygen in water. The main factors affecting the 

concentration of dissolved oxygen in aquatic ecosystems are 

the exchange of dissolved oxygen between the water body 

and the atmosphere, photosynthetic production of oxygen by 

green aquatic plants, and consumption of oxygen by bacteria 

and other aquatic organisms during the breakdown of organic 

matter (Radtke and others, 1998; Boyd, 2000). 

Saturation levels of dissolved oxygen ranged from more 

than 100 percent of saturation at gage DR3 during several 

periodic sampling events to less than 25 percent of saturation 

at gages SG1 and W4 during August and September 2007 

(table 11). Saturation with respect to dissolved oxygen was 

highest where there was active water movement, such as in 

the upland areas (DD1, DD4, DR1) during times of high flow 

(April and May 2008), because water movement enhances the 

exchange of oxygen between water and the atmosphere. Saturation levels of dissolved oxygen were lowest where there was 

little or no water movement, higher temperatures, and substantial decay of organic matter. These processes predominate in 

the wetland areas (W4, DR2, W2) and stagnant ditches (SG1), 

because decomposition of organic matter consumes dissolved 

oxygen, the lack of water movement restricts the exchange of 

oxygen with the atmosphere, and higher water temperatures 

reduce the solubility of oxygen in water (Stumm and Morgan, 

1981).

pH

Many reactions that affect water quality are pH-dependent. The pH of water is a measure of the effective hydrogenion concentration: pH standard unit values are the negative 

base-10 logarithm of hydrogen-ion activity, in moles per liter 

(Radtke and others, 1998). The pH is affected by interrelated 

chemical reactions that either produce or consume hydrogen 

ions (Hem, 1992). The pH of natural water is an indicator of 

the status of these chemical reactions. The pH of pure water at 

25°C is 7.00. The pH can be affected by the presence of dissolved gases—particularly carbon dioxide, which can reduce 

pH by creating carbonic acid. 

The discrete pH values measured during periodic sampling range from 6.51 to 8.41 standard units (table 11). These 

values are within the Illinois Pollution Control Board (IPCB) 

criteria for the range of values within the Lake Michigan Basin 

of 6.5–9.0 standard units (Illinois Pollution Control Board, 

1978). pH values show no consistent trends through time or 

with location.

Specific Conductance

Specific conductance is a measure of the electrical conductance of a unit volume of water at 25°C and is a function 

of the combined concentrations of dissolved ions in the water. 

As a consequence, specific conductance is generally a good 

indicator of the overall dissolved solids within the area of 

DATE

July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July

2007 2008

-5

0

5

10

15

20

25

TEMPERATURE, IN DEGREES CELSIUS

W1/DD1

W3

1

7

12

18

Figure 18. Surface-water temperatures recorded at well locations in the vicinity of the Spring Bluff Nature Preserve, 

Winthrop Harbor, Illinois, September 2007–June 2008. 
42 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

investigation. Discrete specific-conductance values measured 

during the periodic sampling ranged from 664 to 2,406 μS/cm 

during the investigation (table 11), with consistently higher 

values measured on August 29, 2007. The higher specific conductance during August may reflect the addition of dissolved 

solids to, or the remobilization of dissolved solids within, the 

wetlands during the large precipitation events that occurred in 

the days and weeks before this sampling event.

Specific conductance was highest at the upland gages 

(DR1, DD1, DD4) and tended to decrease toward Lake 

Michigan, indicating that dissolved solids concentration tends 

to be highest as it enters the study area (especially at DD4) 

and declines with increasing distance through the wetland 

complex. This pattern is most apparent along the Dead River, 

where specific conductance showed a consistent decrease 

for gages DR1–DR3. In the NUIBSP, specific conductance 

showed a consistent decrease from gage DD4 to gages SG1 

and W4, and from gages SG1 and W4 to gage DD3. In the 

SBNP, specific conductance consistently decreased from gage 

DD1 to gages DD2 and W3, and from gages DD2 and W3 to 

gage W2. These patterns indicate that physical and chemical 

processes occurring in the wetland complex are improving 

overall water quality before it enters Lake Michigan.

Specific conductance obtained from the continuous 

measurements collected by using the multiparameter dataloggers demonstrates several trends (fig. 19). These patterns are 

summarized below.

First, several stations had seasonal trends whereby 

specific conductance is higher in winter months than spring 

or fall, and they additionally had obvious short-term fluctuations—on the order of hours to days. These trends likely are 

owing to the presence of road salt in urban runoff during the 

winter months, which can cause sharp increases in specific 

conductance during at least some snowmelt events, as well 

as smaller increases during winter that can last on the order 

of weeks to months. Stations showing both long-term and 

short-term increases in winter include well 1 and gage W1. 

These stations are near roadways or along major drainageways 

that may carry urban-runoff-impacted surface water into and 

through the wetland complex.

Second, there are long-term differences among stations. 

Stations 12 and W3 had specific conductances that are much 

higher than those at other continuously monitored stations, 

averaging more than 1,500 μS/cm for the majority of the 

year, and they remained high except for short-term (hours to 

days) declines that are likely the result of precipitation diluting the dissolved solids in the surface water. The cause of the 

high specific conductance at these gages is not known with 

certainty. 

Third, the lowest recorded values for specific conductance were in the CPSNA, at the stations most distant from 

surface inflows. This pattern indicates that runoff may be the 

source of higher specific conductance in the coastal wetland 

complex.

Fourth, intermittent downward spikes in specific conductance were recorded for all stations. These downward spikes 

lasted hours to several days and likely were caused by dilution 

resulting from precipitation or snowmelt occurring near the 

gage that was not impacted by road salt from urban runoff.

Invalid data resulting from identified problems such 

as dry or frozen instruments, inaccurate calibrations that 

were identified during post deployment calibration checks, 

and similar quality-control issues were removed. However, 

some apparent data inconsistencies were not resolved during 

quality-control checks of the data because a cause could not be 

identified. These inconsistencies include repetitive decreases 

noted after servicing of instruments (see March and May 2008 

at loggers W3 and H12) and rapid increases or decreases in 

value for the duration of a deployment between calibrations 

(for instance, H1 in March 2008). Trends and conclusions cannot be identified from these data, and, although not excluded 

from the graphs, will not be considered further.

Turbidity

Turbidity was continuously recorded at gages W1, W3, 

and DD1. Turbidity is a measure of the amount light dispersion by particles suspended in water. Turbidity is proportional 

to suspended particulate content (Lewis, 1996), although 

specific correlations cannot be made without calibration. Suspended sediment in surface water may restrict sunlight penetration or negatively affect vegetation in other ways, including smothering native vegetation when it settles or increasing 

the load of nutrients and contaminants that are associated with 

sediment. The suspended-sediment content in surface runoff 

may be elevated in areas with substantial agricultural or urban 

land use relative to natural land use because of increased 

erosion owing to reductions in the amount of vegetation land 

cover, more voluminous runoff, and more rapid streamflows.

Continuous recording water-quality instruments were 

installed to identify trends in turbidity and, by inference, 

suspended-sediment concentration in the vicinity of the SBNP 

(fig. 20). Surface water flows from Dead Dog Creek at gage 

DD1 at the western edge of the coastal complex eastward 

toward W3, in an emergent marsh just in the west-central 

part of the SBNP, then in part northward towards W1. No 

substantial increases in turbidity were observed at gage W1 

during October 2007–January 2008, indicating that influent 

sediment plumes may be highly attenuated at this point in 

the flow pathway. For this reason, the instrument at gage W1 

was moved to gage DD1 in January 2008 for the purpose of 

documenting turbidity at the entrance to the preserve. Several 

spikes in turbidity lasting several hours to days were periodically observed at gage DD1 in conjunction with precipitation 

events. Turbidity spikes at gage W3 typically were small and 

showed moderate correlation with precipitation events. Spikes 

in turbidity not associated with precipitation or snowmelt 

events are assumed to be the result of sediment disturbance by 

visitors or animals.
Surface-Water Quality 43

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

2,200

SPECIFIC CONDUCTANCE, IN MICROSIEMENS 

PER CENTIMETER

PRECIPITATION AT KENOSHA, WIS., IN INCHES

EXPLANATION

Specific conductance

Well 1

Well 7

Well 12

Well 18

Dead Dog West (gage W1 

 after move)

Dead Dog East (gage W3)

Gage WI before move

Precipitation

DATE

July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July

2007 2008

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0

100

200

300

400

TURBIDITY, IN FORMAZIN NEPHELOMETRIC UNITS (FNU)

PRECIPITATION AT KENOSHA, WIS., IN INCHES

Gage W1 turbidity

Gage W3 turbidity

Gage DD1 turbidity

Precipitation

DATE

Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July

2007 2008

500

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

Figure 19. Specific conductance of surface water and amount of precipitation at selected gages and well locations in the vicinity of 

the Spring Bluff Nature Preserve, Winthrop Harbor, Illinois, July 2007–July 2008. 

Figure 20. Turbidity and 

precipitation in Dead Dog 

Creek and wetlands in 

the vicinity of the Spring 

Bluff Nature Preserve, 

Winthrop Harbor, Illinois, 

October 2007–July 2008. 
44 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Chloride

In this region, naturally occurring concentrations of chloride in precipitation, surface water, and shallow groundwater 

are low. Chloride is a component of road salt that is applied to 

roads in the area for deicing. It also is present at elevated concentrations in wastewater, including septic discharge, although 

most of the residences in the watersheds draining the coastal 

complex are not on septic systems. Chloride is a soluble element, and its relative concentration can often be used to infer 

the presence and extent of urban runoff (Feth, 1981). Plants 

have varying levels of tolerance to chloride, and excessive 

concentrations of chloride can limit growth of some plants, 

especially native freshwater species that are not adapted to 

higher chloride levels. High chloride levels are associated 

with reductions in plant diversity in wetlands and facilitate the 

dominance of a few tolerant species (Panno and others, 1999). 

Concentrations of chloride in samples of surface 

water ranged from 45 to 400 mg/L during the investigation 

(table 12). These concentrations were below the IPCB Water 

Quality Criterion for the Lake Michigan Basin of 500 mg/L. 

Samples collected at the points of outflow to the lake did, 

however, exceed the IPCB standard for chloride concentration 

in the open water of Lake Michigan of 12 mg/L.

Table 12. Concentrations of laboratory-determined constituents in surface water at gages in the vicinity of the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, near Winthrop Harbor and Waukegan, Illinois, 

May 31, 2007–May 13, 2008. Locations of gages are shown in figures 2–4. —Continued

[mg/L, milligrams per liter; <, less than reporting level; e, estimated concentration; --, sample not collected; bold denotes sample/duplicate]

Gage

05/31/2007 06/27/2007

Nitrate plus 

nitrite as 

nitrogen, 

mg/L

Phosphorus, 

mg/L

Chloride, 

mg/L

Suspended 

sediment, 

mg/L

Nitrate plus 

nitrite as 

nitrogen, 

mg/L

Phosphorus, 

mg/L

Chloride, 

mg/L

Suspended 

sediment, 

mg/L

DD1 0.31 0.036 140 40 0.34 0.037 140 150

DD3 <.06 .015 120 54 <.06 .016 82 240

DD4 .064 .023 400 31 <.06 .013 270 32

W1 .03 e .015 100 -- .032 e .015 97 --

W3 <.06 .053 130 -- <.06 .025 120 --

W4 <.06 .027 120 -- <.06 .119 110 --

DR1 .7 .042 140 54 .3 .045 83 25

DR2 <.06 .023 190 155 <.06 .032 120 17

DR3 <.06 .012 120 22 <.06 .006 97 21

Gage

07/30/2007 08/29/2007

Nitrate plus 

nitrite as 

nitrogen, 

mg/L

Phosphorus, 

mg/L

Chloride, 

mg/L

Suspended 

sediment, 

mg/L

Nitrate plus 

nitrite as 

nitrogen, 

mg/L

Phosphorus, 

mg/L

Chloride, 

mg/L

Suspended 

sediment, 

mg/L

DD1 0.31/0.31 0.042/0.042 140/140 166 0.318 0.029 100 40

DD3 -- -- -- -- .06 .018 99 51

DD4 -- -- -- -- <.06 .018 160 34

W1 -- -- -- -- .041 e .032 63 --

W3 <.06 .029 160 -- <.06 .025 92 --

W4 <.06 .054 130 -- <.06 .12 120 --

DR1 .437 .040 190 45 .543 .041 170 100

DR2 <.06 .027 110 22 <.06 .039 125 64

DR3 <.06 .009 60 6 <.06 .008 93 60
Surface-Water Quality 45

Table 12. Concentrations of laboratory-determined constituents in surface water at gages in the vicinity of the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Illinois Beach State Park, near Winthrop Harbor and Waukegan, Illinois, 

May 31, 2007–May 13, 2008. Locations of gages are shown in figures 2–4. —Continued

[mg/L, milligrams per liter; <, less than reporting level; e, estimated concentration; --, sample not collected; bold denotes sample/duplicate]

Gage

09/18/2007 11/27/2007

Nitrate plus 

nitrite as 

nitrogen, 

mg/L

Phosphorus, 

mg/L

Chloride, 

mg/L

Suspended 

sediment, 

mg/L

Nitrate plus 

nitrite as 

nitrogen, 

mg/L

Phosphorus, 

mg/L

Chloride, 

mg/L

Suspended 

sediment, 

mg/L

DD1 0.202 0.021 130 55 <0.04 0.012 140 140

DD3 -- -- -- -- -- -- -- --

DD4 <.06 .019 230 100 <.04 .014 250 120

W1 <.06 .01 94 -- .023 e .01 92 --

W2 -- -- -- -- -- -- -- --

W3 <.06 .013 130 -- <.04 .008 140 --

W4 <.06 .204 120 -- <.04 .23 95 9

DR1 .722 .026 250 -- .252 .021 180 135

DR2 <.06 .017 170 61 <.04 .005 e 160 56

DR3 <.06 .006 e 94 44 .063 .007 110 60

Gage

04/02/2008 05/13/2008

Nitrate plus 

nitrite as 

nitrogen, 

mg/L

Phosphorus, 

mg/L

Chloride, 

mg/L

Suspended 

sediment, 

mg/L

Nitrate plus 

nitrite as 

nitrogen, 

mg/L

Phosphorus, 

mg/L

Chloride, 

mg/L

Suspended 

sediment, 

mg/L

DD1 1.37 0.023 100 24 0.105/0.101 0.011/0.009 130/130 60

DD3 .268 .013 91 3 <.04 .011 94.5 6

DD4 1.71 .013 350 46 .096 .012 380 26

W1 .037 e .016 45 12 <.04 .010 91 48

W2 -- -- -- 100 .020 e .009 110 13

W3 .781 .015 81 -- <.04 .012 120 13

W4 .028 e .039 78 32 .023 e .047 110 --

DR1 1.3 .022 160 69 .300 .01 230 33

DR2 1.26 .018 130 24 .023 e .009 220 17

DR3 .454 .008 110 22 <.04 .007 170 30

Chloride concentrations in surface water were highest 

at the sampling locations along the bluffs entering the wetland complex and generally declined toward Lake Michigan 

(fig. 21; table 12), a pattern that is consistent with the trends 

in specific conductance. Higher chloride concentrations in the 

samples near the bluff indicate that this water is affected by 

urban runoff in the watershed, including road salt. The lower 

chloride concentrations in the eastern part of the wetland 

complex indicate that the urban runoff has been attenuated, 

most likely by dilution from precipitation and groundwater 

discharge to surface water within the wetlands. Chloride 

concentrations in samples collected on May 13, 2008, are 

representative of the typical spatial patterns in chloride concentrations during the investigation and are discussed because 

they constitute the largest synoptic data set (fig. 21). 

The concentration of chloride entering the SBNP in Dead 

Dog Creek at gage DD1 during May 13, 2008, was 130 mg/L 

(fig. 21). The chloride concentration in the western part of the 

SBNP at the next downstream gage (W3) was similar to the 

average concentrations for the gage during the investigation 

(121 mg/L). The chloride concentration in the eastern part of 

the SBNP at the point where it drains to Lake Michigan (gage 

W2) was 110 mg/L. Chloride concentrations decreased by 

19 percent from gage DD1 to gage W2 on this date.
46 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

WISCONSIN

ILLINOIS

Kenosha County

Lake County

87°50' 87°48' 87°46'

42°24'

42°26'

42°28'

0 1 2 MILES

0 1 2 KILOMETERS

Kellogg

Creek

Dead

Dog Cr.

Bull

Dead River

North

Point

Marina

Cr

Lake Michigan

Base derived from U.S. Geological Survey High-Resolution

Orthoimagery for the Chicago, Ill., urban area, 2005.

EXPLANATION

Lake or pond

Marsh

Stream

Illinois Beach State Park boundary

Dissolved nitrate plus nitrite as nitrogen,

in milligrams per liter (<0.04, less than

detection limit)

Surface-water measuring point and identifier

Chloride concentration, in milligrams per liter

Southern Unit

Illinois Beach

State Park

Northern Unit

Illinois Beach

State Park

Dead Dog Cr. DD1

130

0.105

DD4

381

0.096

DD3

94.5

<0.04

W3

121

<0.04

W4

113

0.023

W2

106

0.020

W1

90.7

<0.04

DR1

234

0.300

DR1

234

0.300 DR2

224

0.023

DR3

172

<0.04

Spring Bluff

Nature Preserve

Chiwaukee Prairie

State Natural Area

Figure 21. Concentrations of chloride and dissolved nitrate plus nitrite as nitrogen in surface water in the vicinity 

of the Spring Bluff Nature Preserve, Chiwaukee Prairie State Natural Area, and Northern and Southern Units of the 

Illinois Beach State Park near Winthrop Harbor and Waukegan, Illinois, May 13, 2008. 
Surface-Water Quality 47

The concentration of chloride in surface water entering 

the NUIBSP from the drainage at gage DD4 during May 13, 

2008, was about 380 mg/L (fig. 21). The chloride concentration in the central part of the NUIBSP at the next downstream 

gage (W4) was substantially lower (about 110 mg/L). The 

chloride concentration in the eastern part of the NUIBSP at the 

discharge point to Lake Michigan (gage DD3) was 95 mg/L. 

Chloride concentrations decreased by about 75 percent from 

gage DD4 to gage DD3 on this date.

The concentration of chloride entering the SUIBSP in 

Bull Creek at gage DR1 during May 13, 2008, was 320 mg/L 

(fig. 21). The chloride concentration in the western part of the 

SUIBSP at the next downstream gage (DR2) was 220 mg/L. 

The chloride concentration in the eastern part of the SUIBSP 

at the point where the Dead River drains to Lake Michigan 

(gage DR3) was 170 mg/L. Chloride concentrations decreased 

by almost 50 percent from gage DR1 to gage DR3 on this 

date.

Chloride concentrations in surface water at the SBNP 

gages were similar through time during most of the investigation but were somewhat lower during the August 29, 2007, and 

April 2, 2008, sampling events (table 12). The low chloride 

concentrations measured on these dates likely was the result of 

dilution by recent rainfall (August) or rainfall and snowmelt 

(April).

Chloride concentrations in surface water at the NUIBSP 

gages were similar through time at gages DD3 and W4 during 

most of the investigation but showed a small overall decrease 

at gage W4 during the investigation (table 12). Chloride 

concentrations at gage DD4 were usually the highest measured 

in the study area but were substantially lower during the June–

November 2007 sampling events than during the spring 2007 

and 2008 sampling events. The high chloride concentrations at 

gage DD4 during the spring months likely reflect the relatively 

large contribution of urban runoff in this small, highly urbanized, watershed. In particular, the transport of wintertimeapplied road salt by the spring rains apparently added to the 

chloride concentrations at this time. The comparatively low 

chloride concentrations detected during the summer and fall of 

2007 also may have been owing to a relatively higher contribution from groundwater inflow to the stream. Groundwater 

likely has lower concentrations of chloride in comparison to 

stormwater runoff at gage DD4. 

Chloride concentrations in Bull Creek and the Dead 

River at the SUIBSP gages were variable during most of the 

investigation but were highest or above average at all of the 

gages during the May 15, 2008, sampling event (table 12). The 

high chloride concentrations in the water during this sampling 

event may reflect the high percentage of water in this large, 

moderately urbanized watershed that received springtime 

runoff of previously applied road salt and other urban effects 

as discussed above.

Nitrogen and Phosphorous 

Nitrogen and phosphorous are essential nutrients for 

plant growth. They are components of fertilizers that can be 

leached into agricultural or urban runoff. Plants take up these 

nutrients from soil and water during the growing season and 

release them when the plants die and decay. Relatively large 

concentrations of nutrients associated with anthropogenically 

affected runoff can result in increased growth of algae and 

plant species that are adapted to store additional nutrients in 

the form of carbohydrates, resulting in increased plant vigor 

and spread at the expense of less competitive plant species 

that are adapted to nutrient-limited or nutrient-poor conditions 

(Woo and Zedler, 2002; Kercher and Zedler, 2004b). 

Concentrations of nitrate plus nitrite as nitrogen (hereafter referred to as “nitrate”) in surface water in the study area 

varied from below the reporting level of 0.04 to 1.7 mg/L 

during the investigation (table 12). Nitrate concentrations did 

not exceed State of Illinois criterion for Finished Water, nor 

did they exceed State criterion for concentrations in the open 

water of Lake Michigan, both of which are 10 mg/L (Illinois 

Pollution Control Board, 1978).

Nitrate concentrations in surface water typically were 

highest along the bluffs entering the wetland complex at gages 

DD1, DD4, and DR1 and generally decreased toward Lake 

Michigan (fig. 21). The higher nitrate concentrations in the 

western part of the wetland complex likely result from agricultural and urban runoff affected by fertilizers and animal and 

septic waste. The lower nitrate concentrations in the eastern 

part of the wetland complex likely reflect the combined effects 

of dilution, uptake of nitrogen by plants and microbiota, and 

the biologic transformation of nitrogen compounds (denitrification) within the wetlands. Nitrate concentrations in samples 

collected on May 13, 2008, indicate a typical pattern in nitrate 

concentrations during the investigation and are discussed 

below because they represent the largest synoptic nitrate data 

set. 

The concentration of nitrate in Dead Dog Creek entering 

the SBNP at gage DD1 during May 13, 2008, was 0.105 mg/L 

(fig. 21; table 12). Nitrate was not detected in the central 

part of the SBNP at gages W3 and W1 at a reporting level of 

0.04 mg/L. Nitrate was detected at an estimated concentration 

of 0.02 mg/L (concentrations below the reporting level are 

estimated) in the northeastern part of the SBNP where it drains 

to Lake Michigan (gage W2). Nitrate concentrations decreased 

by about 80 percent from gage DD1 to gage W2 on this date.
48 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

The concentration of nitrate in surface water entering 

the NUIBSP from the culvert monitored by gage DD4 during 

May 13, 2008, was 0.096 mg/L (fig. 21; table 12). The nitrate 

concentration in the central part of the NUIBSP at the next 

downstream gage (W4) was estimated to be 0.023 mg/L. The 

nitrate concentration in the eastern part of the NUIBSP at the 

outflow to Lake Michigan (gage DD3) was below the reporting level of 0.04 mg/L. Nitrate concentrations decreased by at 

least 60 percent from gage DD4 to gage DD3 on this date.

The concentration of nitrate entering the SUIBSP in Bull 

Creek at gage DR1 during May 13, 2008, was 0.30 mg/L 

(fig. 21; table 12). The nitrate concentration in the western part 

of the SUIBSP at the next downstream gage (DR2) was estimated at 0.023 mg/L. The nitrate concentration in the eastern 

part of the SUIBSP at the point where the Dead River drains to 

Lake Michigan (gage DR3) was below the reporting level of 

0.04 mg/L. Nitrate concentrations decreased by at least 85 percent from gage DR1 to gage DR3 on this date.

Nitrate concentrations at the gages were similar through 

time during most of the investigation but were substantially 

higher during the April 2, 2008, sampling than during the other 

sampling events at every sampling point (table 12). The high 

nitrate concentrations in samples collected on this date likely 

were the result of nitrate released from fall fertilizer applications and the decay of organic matter within the watershed 

(including within the wetlands) during the winter months, 

which was transported to the coastal complex in stormwater 

and snowmelt.

Concentrations of dissolved phosphorous in surface water 

ranged from an estimated concentration of 0.005 mg/L to 

0.23 mg/L during the investigation (table 12). Several samples 

collected at the points of outflow to Lake Michigan exceeded 

IPCB standards for total phosphorus concentration in the 

open waters of Lake Michigan of 0.007 mg/L. Phosphorus, 

unlike most forms of nitrogen, is strongly sorbed to sediment 

particles and, therefore, phosphorous concentrations often are 

positively correlated with suspended-sediment concentrations 

(Hem, 1992). As a consequence, dissolved phosphorous concentrations from filtered samples (such as were collected for 

this investigation) typically are lower than total phosphorous 

concentrations that would be present in unfiltered samples. 

Therefore, the dissolved phosphorous data indicate that total 

phosphorous concentrations in surface-water discharging from 

the wetland complex may pose a risk to Lake Michigan.

Dissolved phosphorous concentrations in samples collected on April 2, 2008, are typical of the patterns in the study 

area during the investigation. These data are discussed because 

they are the largest representative data set (table 12). May 13, 

2008, data are not discussed because dissolved phosphorus 

concentrations on that date tended to be atypically low at 

gages DD1, DR1, and DR2, which resulted in somewhat 

atypical patterns in dissolved phosphorous concentrations in 

the SBNP and SUIBSP. The fact that dissolved phosphorous 

concentrations were low on May 13, 2008, whereas dissolved 

nitrate concentrations were high, indicates either that the 

nutrients are derived in part from different sources or that the 

proportions of total and dissolved phosphorous differed on 

May 13 from those during other sampling events.

The concentration of dissolved phosphorous in Dead Dog 

Creek entering the SBNP at gage DD1 during April 2, 2008, 

was 0.023 mg/L (fig. 22). The dissolved phosphorous concentrations in the central part of the SBNP at gages W3 and W1 

were 0.015 and 0.016 mg/L, respectively. No phosphorous 

data are available for this date at gage W2. Dissolved phosphorous concentrations were about 35 percent lower between 

gages DD1 and W3 on this date. Patterns in dissolved phosphorous concentrations were variable in the SBNP. On most 

of the sampling dates, a pattern of decreasing concentrations 

between gages DD1 and W1 and W3 was observed, indicating 

that the SBNP typically is a sink for dissolved phosphorous 

(table 12). However, on some sampling dates, concentrations 

were similar throughout the area or higher at gage W1 or W3, 

indicating that processes in the SBNP could release dissolved 

phosphorous to the water column on occasion.

The concentration of dissolved phosphorous entering 

the NUIBSP at gage DD4 on April 2, 2008, was 0.013 mg/L 

(fig. 22). The dissolved phosphorous concentration in the 

central part of the NUIBSP at gage (W4), which is not part of 

the ditch system connecting DD4 and DD3, was substantially 

higher (0.039 mg/L). The phosphorous concentration in the 

eastern part of the NUIBSP at the outflow to Lake Michigan 

(gage DD3) was identical to that at gage DD4. These patterns 

in phosphorous concentrations were consistent with the patterns in the NUIBSP during the other sampling events. 

The concentration of dissolved phosphorous entering 

the SUIBSP in Bull Creek at gage DR1 on April 2, 2008, was 

0.022 mg/L (fig. 22). The dissolved phosphorous concentration in the western part of the SUIBSP at the next downstream 

gage (DR2) was 0.018 mg/L. The dissolved phosphorous 

concentration in the eastern part of the SUIBSP at the outflow 

of Dead River to Lake Michigan (gage DR3) was 0.008 mg/L. 

Dissolved phosphorous concentrations decreased by about 

66 percent from gage DR1 to gage DR3 on this date, which is 

consistent with the results of the other sampling events in the 

SUIBSP.
Surface-Water Quality 49

WISCONSIN

ILLINOIS

Kenosha County

Lake County

87°50' 87°48' 87°46'

42°24'

42°26'

42°28'

0 1 2 MILES

0 1 2 KILOMETERS

Kellogg

Creek

Dead

Dog Cr.

Bull

Dead River

North

Point

Marina

Cr

Spring Bluff

Nature Preserve Lake Michigan

Base derived from U.S. Geological Survey High-Resolution

Orthoimagery for the Chicago, Ill. urban area, 2005.

EXPLANATION

Lake or pond

Marsh

Stream

Illinois Beach State Park boundary

Surface-water measuring point and identifier,

and dissolved phosphorous concentration,

in milligrams per liter

Southern Unit

Illinois Beach

State Park

Northern Unit

Illinois Beach

State Park

Chiwaukee Prairie

State Natural Area

Dead Dog Cr. DD1

0.023

DD4

0.013

DD3

0.013

W3

0.015

W4

0.039

W2

W1

0.016

DR1

0.022

DR1

0.022

DR2

0.018

DR3

0.008

Figure 22. Concentrations of dissolved phosphorous in surface water in the vicinity of the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Northern and Southern Units of the Illinois Beach State Park 

near Winthrop Harbor and Waukegan, Illinois, April 2, 2008. 
50 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Dissolved phosphorous concentrations in the SBNP 

showed an overall decrease through time during May 31, 

2007–November 27, 2007, at gages DD1 and W3 and were 

similar to fall 2007 concentrations for the subsequent sampling events (table 12). Except for a high value during the 

August 29, 2007, sampling event, dissolved phosphorous concentrations at gage W1 showed little variation. The trends in 

dissolved phosphorous concentrations at gages DD1 and W3 

may be the result of increased phosphorous uptake by plants 

in the watershed during the 2007 growing season, likely after 

fertilizer application in residential areas during the spring, 

and dilution by precipitation during the spring 2008 sampling 

events. Uptake of phosphorous within the wetland complex 

during the growing season by plants and microbiota, as well 

as mineral precipitation and sorption onto sediments, also may 

have played a role. The relatively high dissolved phosphorous 

concentration in the sample collected at gage W1 during the 

August 29, 2007, sampling event may reflect the release of 

dissolved phosphorous from organic matter and pore water in 

sediments within parts of the wetland, perhaps exacerbated 

by mechanical disturbance to the plants and sediments in this 

area from flow owing to the record precipitation in the days 

and weeks preceding the sampling. Dissolved phosphorous 

concentrations in the NUIBSP were relatively stable through 

time at gages DD3 and DD4 (table 12). Concentrations at gage 

W4 increased overall from 0.027 to 0.23 mg/L during the 2007 

sampling events, then were less than 0.05 mg/L during the 

2008 sampling events. The increasing dissolved phosphorous 

concentrations in the samples from gage W4 during the spring 

and summer months may reflect the release of phosphorous 

from sediments and decaying plants, perhaps in combination 

with a lack of dilution from incoming surface flow to this part 

of the wetland complex. The comparatively low dissolved 

phosphorous concentrations in the spring 2007 and 2008 samples may reflect dilution by spring runoff and precipitation. 

Dissolved phosphorous concentrations at the SUIBSP 

gages showed an overall decrease through time during the 

investigation (table 12). Decreases were greatest at upstream 

gage DR1, moderate at gage DR2, and smallest at downstream 

gage DR3. These trends may be related to increasing uptake 

of phosphorous by plants in the watershed and the coastal 

complex during the 2007 growing season, likely after fertilizer 

application in the spring, and dilution by precipitation during the spring 2008 sampling events. Dissolved phosphorous 

concentrations in the samples from gages DD1 and DR1 are 

highly correlated (R2=0.83), indicating that the timing and 

processes affecting phosphorous inputs to the Bull Creek 

Watershed (presumably fertilizer application and uptake by 

plants) are similar to those affecting inputs to the Dead Dog 

Creek Watershed. 

Suspended Sediment

Insufficient data were collected to create a sediment 

budget for the wetland complex, and the data are inadequate 

to evaluate whether or not this area is a net source or trap for 

sediment under routine conditions. However, samples collected in the northern part of the study area at the SBNP and 

the NUIBSP during the routine periodic sampling indicate that 

suspended-sediment concentrations in the creeks entering the 

wetlands at gages DD1 and DD4 typically were less than the 

concentrations exiting the wetland complex at gages DD3 and 

W2 (table 12). Samples collected at the SUIBSP during the 

periodic sampling events indicate that suspended-sediment 

concentrations in Bull Creek at gage DR1, before it enters the 

wetland complex, typically were greater than the concentrations within the wetlands at gage DR2 by about a factor of 2. 

Sediment concentrations at gage DR2 typically were similar to 

those exiting the Dead River into Lake Michigan at gage DR3. 

Suspended-sediment concentrations showed no relation 

to stream discharge (Pearson product moment correlation coefficient of 0.01) during the periodic sampling events. However, 

sediment concentrations were higher in the creeks and ditches 

where flow was active than in the parts of the wetland complex where there was minimal flow.

Suspended-sediment concentrations from intensive 

sampling on Dead Dog Creek at gage DD1 during and 

after precipitation events on August 23, September 25, 

October 14, 2007, March 26–April 2, 2008, and April 11, 

2008, indicate that large changes in sediment concentrations 

occurred over a period of hours during and after these events 

(fig. 23). Although not necessarily highly correlated over 

the entire event (R2=0.58), large increases in suspendedsediment concentration at gage DD1 were associated with 

large increases in water level (and therefore discharge) at the 

stream. Large decreases in suspended-sediment concentration 

were associated with the large decreases in water level (and 

discharge) after the water level peaked. 
Surface-Water Quality 51

Suspended-sediment concentrations in samples collected at gages W1, W2, W3, and DD2 at the SBNP during 

March 31–April 2, 2008, indicate that sediment concentrations 

in the ditches and wetlands can be more than two orders of 

magnitude less than the highest concentrations entering the 

SBNP at gage DD1 (fig. 24). Although interpretation is limited 

by a lack of intensive sampling at several gages, the peak of 

the sediment pulse appears to move from gage DD1 (peak 

about 1330 hours on March 31) to W3 (about 1530 hours on 

March 31), then to gages W1 and DD2 (about 0930 hours 

on April 1) and W2 (peak at end of sampling at 1115 hours 

on April 2). Suspended sediment concentrations showed no 

clear increase at gage DD3, located near the outlet to Lake 

Michigan at the NUIBSP (fig. 24). Patterns and timing of the 

peaks in the trends in sediment concentrations were consistent 

with the patterns and timing of the water-level response to the 

June 8 rain event (fig. 15). Maximum suspended-sediment 

concentrations detected at the points of discharge to Lake 

Michigan (gages W2 and DD3) were more than an order of 

magnitude lower than that at gage DD1, indicating that during 

storm events the ditches and wetlands function as sediment 

traps, removing much of the sediment from the water before it 

discharges to Lake Michigan. 

Similarly, intensive sample collection on Bull Creek at 

gage DR1 during and after precipitation on August 23 and 

October 15–16, 2007, and April 10–13, 2008, also indicates 

that large changes in suspended-sediment concentrations 

occurred over a period of hours during and after the storms. 

Because water-level data were not continuously measured 

at gage DR1, changes in suspended-sediment concentration 

at gage DR1 cannot be related to gage height. However, if it 

is assumed that water levels at gages DD1 and DR1 follow 

similar trends, changes in suspended-sediment concentration 

at Bull Creek also are directly related to the change in stream 

elevation (and discharge) (fig. 25). 

596.80

597.20

597.60

598.00

598.40

598.80

26 27 28 29

March 2008 April 2008

30 31 1 2

DATE

WATER LEVEL, IN FEET ABOVE NORTH AMERICAN VERTICAL DATUM OF 1988

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

CONCENTRATION OF SUSPENDED SEDIMENT, IN MILLIGRAMS PER LITER

Creek water level

Concentration of suspended sediment

Figure 23. Water-level elevation and concentration of suspended sediment in Dead Dog Creek at gage DD1, Spring 

Bluff Nature Preserve, Winthrop Harbor, Illinois, March 26–April 2, 2008. 
52 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Figure 24. Concentration of suspended sediment in the Spring Bluff Nature Preserve, Northern Unit Illinois 

Beach State Park, and Chiwaukee Prairie State Natural Area, near Winthrop Harbor and Waukegan, Illinois, 

March 26–April 2, 2008. (Note variable scale in top graph.) 

DATE

CONCENTRATION OF SUSPENDED SEDIMENT, IN MILLIGRAMS PER LITER

CONCENTRATION OF SUSPENDED 

SEDIMENT, IN MILLIGRAMS PER LITER

200

400

600

800

1,000

1,200

1,400

1,600

1,800

0

0

20

20

40

40

60

60

50

30

10

70

80

100

120

140

160

180

DD1

DD2

DD3

W1

W2

W3

26

March 2008 April 2008

27 28 29 30 31 1 2

DATE

March 2008 April 2008

31 1 2

EXPLANATION

(See expanded view below)

Gage
Surface-Water Quality 53

Suspended-sediment concentrations in samples from the 

wetland areas at the SUIBSP at gages DR2 and DR3 during 

the precipitation event of April 10–13, 2008, indicate that 

sediment concentrations in the wetlands were substantially 

less (5 to 54 mg/L) than those in samples collected from the 

stream entering the wetlands at gage DR1 (maximum concentration 1,800 mg/L). Concentrations at gage DR2 and DR3 are 

similar. These patterns are consistent with patterns in sediment 

concentration collected at the periodic sampling events. These 

patterns indicate that the wetlands, and especially the manmade ponds upstream from gage DR2, trap sediment entering 

the SUIBSP.

Apparent Attenuation of Suspended Sediment, 

Chloride, Dissolved Phosphorous, and Nitrate 

Within the Wetland Complex

Surface-water-quality data obtained during the period of 

sample collection indicate that urban and agricultural runoff 

affects water quality entering the wetland complex. It is probable, therefore, that the surface water entering, and within, 

the wetland complex has higher concentrations of numerous 

chemical constitutes, including chloride, nitrate, and possibly 

phosphorous and suspended sediment, than were present during presettlement conditions.

The concentration of constituents entering the wetland 

complex appear to be affected by the area and density of urban 

and agricultural land use within the watershed. The unnamed 

stream monitored at gage DD4 drains a small watershed with 

about 72 percent urban land use. This watershed has high 

concentrations of chloride (relative to gages DD1 and DR1) 

but has low concentrations of dissolved nitrate, dissolved 

phosphorous, and suspended sediment. Bull Creek and Dead 

Dog Creek drain larger watersheds with low to moderate 

percentages of agricultural land use (8 and 43 percent, respectively) and urban land use (50 and 26 percent, respectively). 

These watersheds have high (and often similar) concentrations 

of nitrate, dissolved phosphorous, and suspended sediment 

(during flood events), as well as moderate concentrations of 

chloride. 

Within the various subunits of the wetland complex, 

specific conductance values and concentrations of chloride, 

nitrate, and suspended sediment—and dissolved phosphorous 

in some areas—decreased by a combination of chemical, 

biologic, and hydraulic processes occurring in the wetland 

complex. As a consequence, the concentrations of these constituents in water exiting the wetland complex and entering 

Lake Michigan, with the exception of suspended sediment and 

phosphorous in the northern part of the study area during some 

of the period of investigation, were lower than the respective 

concentrations entering the wetland complex. The degree of 

attenuation within the various subunits was consistently highest in the SUIBSP, the largest of the wetlands with potentially 

the longest residence time for water. The degree of attenuation is smallest in the NUIBSP, the driest part of the study 

area, where the degree of hydrologic alteration to the wetland 

appears to be moderate to large owing to the effects of the 

roads, ditches, and culverts in this area. Because the ditches 

facilitate the movement of water from the NUIBSP to the lake, 

water entering the NUIBSP has relatively little hydrologic 

interaction with the wetlands. When water can flow through 

Figure 25. Concentration of suspended sediment in Bull Creek at gage DR1 and water level of Dead Dog Creek at gage DD1, near 

Winthrop Harbor and Waukegan, Illinois, April 10–13, 2008. 

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

10 11 12 13

APRIL 2008

597.60

597.80

598.00

598.20

598.40

598.60

598.80

599.00

599.20

Creek water level

Concentration of sediment

CONCENTRATION OF SUSPENDED 

SEDIMENT, IN MILLIGRAMS PER LITER

WATER LEVEL, IN FEET ABOVE NORTH 

AMERICAN VERTICAL DATUM OF 1988
54 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

the culvert at gage DD3, it is likely that the residence time of 

water in the NUIBSP is shorter than in the other parts of the 

study area. Moderate chemical attenuation occurred in the 

SBNP and CPSNA (relative to the NUIBSP and SUIBSP). The 

SBNP part of the wetland complex also has experienced substantial hydrologic alteration, partly because of these alterations water entering the SBNP and CPSNA has substantial 

residence time and hydrologic interaction with the wetlands 

before exiting to Lake Michigan. All preserves except the 

NUIBSP have substantial areas of standing water through 

which water entering the coastal complex must flow before 

discharging to Lake Michigan. These wet areas likely account 

for the larger improvements in water quality because they are 

the locations where many of the processes that improve water 

quality occur, such as sediment deposition, dilution, biological 

and chemical uptake, and precipitation onto organic matter.

Relation of Hydrology and Water 

Quality to Invasive Species

The vegetation changes observed within the wetland 

complex probably have multiple causes. The most apparent 

causes are hydrologic, but chemical effects also are evident. 

Statistical analyses indicate a strong positive correlation 

between Typha spp. importance (which is correlated with its 

abundance) and all indicators of wetness: mean depth to water 

(R2=-0.68), growing season mean depth to water (R2=-0.68), 

inundation duration (R2=0.67), and growing season inundation duration (R2=0.71) (table 13). These results indicate 

that Typha spp., the dominant herbaceous invasive species in 

many of the wetlands in the SBNP, is primarily impacting the 

wettest areas and that any anthropogenically induced increase 

in the hydroperiod in parts of the wetlands would increase the 

expansion of invasive species. Additionally, these statistical 

analyses show a strong relation between observed vegetative 

wetness and all measures of hydrology, presenting consistent 

characteristics for monitored sites. Analyses also show that 

Typha spp. abundances are not correlated with land-surface 

elevations (R2=-0.30), indicating the invasive impacts are not 

elevation controlled. The mean coefficient of conservatism did 

not correlate significantly with hydrologic wetness indicators 

(for example, R2=0.14 with mean depth to water). This result 

likely reflects the consistently high quality of vegetation in 

the preserves, with even impacted areas still having enough 

native species to retain high mean values for the coefficient 

of conservatism. Native species richness indices were significantly correlated with decreased wetness (for example, 

R2=0.71 with mean depth to water), but this finding could 

result from the fact that even pristine wet communities usually 

have less diverse plant assemblages than their drier counterparts. No significant correlations were observed with Phragmites australis (absolute value of all R2

 values were less than 

0.40), perhaps because of the small number of samples that 

contained the species. 

These analyses are consistent with the data collected at 

the quadrats near the monitoring wells (table 10), which show 

Typha spp. in substantial amounts only in emergent marsh 

communities, where there is long-term standing water and 

average water levels that are near or above land surface. Typha 

spp. importance values appear to be less than 2 until the total 

days of inundation approach 200 (table 10; fig. 26), indicating 

that long-term inundation is required for Typha spp. dominance of the ecological community. Typha spp. importance 

values also are less than 2 until the average water level at a 

given location is at or above land surface (table 10; fig. 27), 

which also indicates that long-term inundation is required for 

Typha spp. dominance. Finally, data from the quadrats indicate 

that the species richness index increases as the depth to water 

increases and that emergent marshes are far less diverse than 

other wetland types (table 10; fig. 28) although, as noted 

earlier, some reduction in richness is expected even in pristine 

wet communities as compared to their drier counterparts.

Given that Typha spp. have not invaded all emergent 

marshes at the study area and that no significant differences in 

hydroperiod were found between emergent marshes measured 

in this study that contain Typha spp. and those that do not, 

other factors may be important to the spread of Typha spp., 

such as the total concentration of dissolved constituents in the 

water (indicated by values of specific conductance) and the 

concentration of nutrients. The only instrumented emergent 

marsh area not invaded by Typha spp. had a low specific conductance value in surface water (fig. 29) and was distant from 

surface-water inputs, possibly indicating a smaller effect from 

agricultural and urban runoff. 

Specific conductance was highly correlated to the relative importance of Typha spp. (R2=0.98) at the four locations 

where specific conductance was continuously monitored in 

emergent marshes in SBNP (fig. 14; table 13), indicating that 

there is an association between those areas affected by highconductivity runoff and the abundance of Typha spp. No correlations were evident for Phragmites australis, perhaps owing 

to the small number of individuals in the samples. The effects 

of other potential factors, such as nitrate concentrations, could 

not be determined because they were not measured in many of 

the wetland areas where vegetation parameters were measured.

Given that both water depth and specific conductance 

were highly correlated with the occurrence of Typha spp., it 

may not be possible to separate the effects of each. These 

factors co-vary because altered stream inputs produce more 

water of higher conductivity in the wetlands. Streams draining 

agricultural and urban areas generally have greater streamflow 

than in the presettlement condition (Booth and Jackson, 1997; 

Konrad and others, 2005; Konrad and Booth, 2005). They also 

generally have higher loads of chloride, nitrate, dissolved and 

suspended solids, and other constituents (Hamilton and others, 

2001). Given the observations and data showing sedimentladen runoff water that enters and flows deeply into the preserves (for example, at W1 and W2 at SBNP), sediment-laden 

runoff could contribute to deleterious effects. 
Table 13. Pearson correlations and two-tailed p-values for selected parameters in the vicinity of the Spring Bluff Nature Preserve, Winthrop HarborJuly 7, 2008.[DTW, depth to water; Sig., significance; corr., correlation; To normalize the data and obtain homogenous variances, all data sets were log-transformed before statistical analysecreation of missing data values during transformations, data sets were uniformly adjusted so that all data had values of one or greater. Correlations were calculated from data at conductance, which was calculated based on data at 4 locations with water-quality dataloggers (wells 1, 7, 12, and 18)]

Growingseason 

mean 

DTW

Inundation 

duration

Growingseason 

inundation 

duration

Landsurface 

elevation

Mean 

specific 

conductance

Typha

relative 

importance 

value

Phragmites

relative 

importance 

value

Mean 

vegetativ

wetnes

Mean DTW Pearson corr. b0.98 b-0.80 b-0.79 a0.45 -0.33 b-0.68 -0.13 b0.85 

Sig. (two-tailed) 0 0 0 .04 .67 0 .57 0 

Growing-season 

mean DTW

Pearson corr. b-.82 b-.81 b.55 -.31 b-.68 -.09 b.88 

Sig. (two-tailed) 0 0 .01 .69 0 .68 0 

Inundation duration Pearson corr. b.97 b-.60 .13 b.67 .13 b-.85 

Sig. (two-tailed) 0 0 .87 0 .56 0 

Growing-season 

inundation duration

Pearson corr. b-.55 .10 b.71 .15 b-.84 

Sig. (two-tailed) .01 .90 0 .51 0 

Land-surface elevation Pearson corr. .26 -.30 .28 b.62 

Sig. (two-tailed) .74 .17 .21 0 

Mean specific 

conductance

Pearson corr. a.98 .20 .56 

Sig. (two-tailed) .02 .80 .44 

Typha relative 

importance value

Pearson corr. .35 b-.66 

Sig. (two-tailed) .11 0 

Phragmites relative 

importance value

Pearson corr. -.10 Sig. (two-tailed) .65 

Mean vegetative 

wetness

Pearson corr. 

Sig. (two-tailed) 

Native mean 

coefficient of conservatism 

Pearson corr. 

Sig. (two-tailed) 

a Correlation is significant at the 0.05 level (two-tailed). Although this is a strong correlation, it is less significant than some other correlations because specific conductance d

collected at only four wells.

b Correlations significant at the 0.01 level (two-tailed).c Native species richness index values will be naturally lower in wet environments, so correlations partly reflect this natural trend and are likely not as significant as indicated
56 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

0

50

100

150

200

250

300

350

400

450

0 5 10 15 20 25 30 35 40

DAYS OF INUNDATION

Emergent marsh

Sedge meadow

Wet prairie

Wet-mesic prairie

Mesic prairie

Panne

0

0

Typha spp. IMPORTANCE VALUE

Nine total data

points overlie

at or near the 

origin (0,0).

Six Mesic prairie

data points

Emergent marsh

Sedge meadow

Wet prairie

Wet-mesic prairie

Mesic prairie

Panne

0 5 10 15 20 25 30 35 40

Land surface

Feet above

land surface Feet below land surface

1.00

0.50

0.00

-0.50

-1.00

-1.50

-2.00

-2.50

-3.00

Typha spp. IMPORTANCE VALUE

DEPTH TO GROUNDWATER ABOVE 

AND BELOW LAND SURFACE, IN FEET

Figure 26. Relation of Typha spp. importance value to days of inundation at vegetation-monitoring points in the Spring Bluff Nature 

Preserve, Northern Unit Illinois Beach State Park, and Chiwaukee Prairie State Natural Area, near Winthrop Harbor and Waukegan, 

Illinois, July 24, 2007–August 27, 2008. 

Figure 27. Relation of Typha spp. importance values to average depth to groundwater at vegetation-monitoring points in the 

vicinity of the Spring Bluff Nature Preserve, Northern Unit Illinois Beach State Park, and Chiwaukee Prairie State Natural Area, 

near Winthrop Harbor and Waukegan, Illinois, July 24–August 27, 2008. 
Relation of Hydrology and Water Quality to Invasive Species 57

0

10

20

30

40

0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000

AVERAGE SPECIFIC CONDUCTANCE, IN MICROSIEMENS PER CENTIMETER

Typha spp. IMPORTANCE VALUE

Figure 28. Relation of species richness index (SRI) values to average depth to groundwater at monitoring-well locations in the Spring 

Bluff Nature Preserve, Northern Unit Illinois Beach State Park, and Chiwaukee Prairie State Natural Area, near Winthrop Harbor and 

Waukegan, Illinois. 

Figure 29. Relation of Typha spp. importance values to specific conductance of surface water in the Spring Bluff Nature Preserve, 

Northern Unit Illinois Beach State Park, and Chiwaukee Prairie State Natural Area, near Winthrop Harbor and Waukegan, Illinois. 

Emergent marsh

Sedge meadow

Wet prairie

Wet-mesic prairie

Mesic prairie

Panne

0 5 10 15 20 25 30 35 40

SPECIES RICHNESS INDEX

Land surface

1.00

0.50

0.00

-0.50

-1.00

-1.50

-2.00

-2.50

-3.00

Feet above

land surface Feet below land surface

DEPTH TO GROUNDWATER ABOVE 

AND BELOW LAND SURFACE, IN FEET
58 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

In addition to agricultural and urban runoff, other 

hydrologic alterations such as berms, roadways, and blocked 

culverts will extend and deepen inundation, and by themselves 

may exacerbate the spread and abundance of Typha spp. The 

hydrology of the only monitored emergent marsh (well 18) 

that lacks Typha spp. does not differ substantially from that of 

other emergent marshes in SBNP and CPSNA. However, it has 

substantially lower specific conductance. It is possible that the 

hydrology near well 18 already has been altered, thus making the area conducive for Typha spp. invasion; it may simply 

require time for colonization of all available habitat. Typha 

spp. has been observed near this location southward along the 

same interdunal swale wetland, suggesting that colonization is 

imminent. Although the controlling aspects of specific conductance cannot be ruled out in this limited study, other ecological 

factors such as seed source, disturbance, and land management 

also may play a role in Typha spp. spread and occurrence.

The study area likely receives much more runoff now 

than during presettlement times because of expanded agricultural and urban land use. Given that some drainageways 

were observed to be restricted by blocked culverts, roadways, 

elevated rains, and earthwork, it is likely that the emergent 

marsh plant community has been expanding at the expense of 

sedge meadows and other wetland communities that formerly occurred at the edges of the fringes of the emergent 

marsh communities. Indeed, dead sedge tussocks have been 

observed in areas now dominated by deep water and Typha 

spp. in the SBNP. These changes are evidence of an increase 

in hydroperiod and an alteration to the wetland plant communities. Memories of long-time residents who recall a general 

lack of standing water throughout the preserve constitute 

anecdotal evidence suggesting an expansion of inundation. 

Although Typha spp. have been present since the early 1900s, 

the observed increase in Typha spp. is likely associated with 

the observed growth of emergent marsh habitat. Decreased 

water quality of runoff also likely is exacerbating the spread 

of Typha spp. and possibly other aggressive plant species, and 

this is likely happening in concert with the extended inundation. Given that the factors are intertwined, it is not possible 

with the current data to separate them completely for the 

purposes of resource managers in determining restoration 

activities. However, additional collection of water-quality 

and plant-community data at more locations may help refine 

knowledge of the specific impacts of each factor.

Because the spread of invasive species in the SBNP 

appears to be affected by the depth of water, reducing the 

water depth with the SBNP wetland may help mitigate these 

effects. Limiting wetness in the affected areas would likely 

require human-induced alterations to the current flow pattern and water-levels via improved culvert maintenance, new 

culverts, and drains. Many of the protected plant communities in the area depend on wet conditions; therefore, such 

changes may have unintended consequences, some of them 

potentially adverse. In order for resource managers to make 

definitive restoration plans and targets, it may be of interest to 

pursue additional quantitative information regarding evidence 

that the study area is currently wetter than it has been in the 

historic past. Given the lack of quantitative assessments of 

past conditions, the only evidence of changes may be contained in the organic soils of the sites. If plant communities 

have changed in the recent past, evidence may exist in the 

form of plant macrofossils, which may be preserved in the 

continually saturated organic soils. If such evidence is found, 

it may be possible to establish target hydroperiods for lowered water levels. Additional mapping of dead sedge tussocks 

and similar features also may provide elevation information 

to assist in determining optimal water levels. Changing the 

quality and quantity of runoff entering the preserves is another 

potential restoration action that also may have unintended 

consequences. Potential management changes that might be 

investigated include rerouting of runoff through the preserves, 

installation of storage structures upstream from the preserves, 

and various watershed management activities. Many of these 

possible management alternatives would be expected to affect 

water quality and quantity, which would address both potential 

causes of vegetation alteration.

Because there is an incomplete understanding of the site 

history, continued monitoring in the area may be beneficial. 

A quantitative record of biological and hydrological changes 

may be important in determining future effects of various 

activities. Additionally, continued monitoring of hydrology and expanded monitoring of water quality may benefit 

land stewards, allowing them to make resource-management 

decisions with a more complete knowledge of site history. 

If further hydrologic alterations are deemed appropriate, the 

monitoring described in this report could provide baseline data 

for resource managers to establish appropriate water-level and 

water-quality objectives in this and similar wetland communities, and for future studies at these sites.

Summary and Conclusions

The U.S. Geological Survey, Illinois State Geological 

Survey and the Lake County Forest Preserve District conducted an investigation of the hydrology, water quality, and 

vegetation in the wetland complex in the Spring Bluff Nature 

Preserve, Chiwaukee Prairie State Natural Area, and Illinois 

Beach State Park (Northern and Southern Units) along the 

shore of Lake Michigan in northeastern Lake County, Ill., and 

adjacent areas of southern Wisconsin. This investigation was 

performed during May 2007–August 2008.

Anthropogenic activities have altered the hydrology 

and water quality of the wetland complex. Agricultural and 

increasingly urban land use in the watersheds likely has 

increased streamflow into the wetland complex relative to presettlement conditions. The natural flow system within the complex has been disrupted by the construction of culverts, roads, 

ditches, storm drains, and berms. The probable net effects 

of these alterations are that storage of water has increased 

in much of the SBNP and western part of the SUIBSP, the 
References Cited 59

movement of surface water has decreased within and between 

the various subunits within the wetland complex (particularly 

the NUIBSP), the hydroperiod has increased in parts of the 

SBNP (particularly the eastern third), and the hydroperiod 

decreased in that part of the NUIBSP that was investigated and 

may have increased in the western part of the SUIBSP. 

Surface-water runoff into the wetland complex likely 

contains higher concentrations of chloride, nitrate, phosphorous, and sediment relative to presettlement conditions. 

Concentrations of these constituents are affected by the percentage of agricultural and urban land use within the watersheds entering the wetland complex. Biological and hydraulic 

processes in the wetlands reduce the concentration of nitrate 

and chloride in the water exiting the coastal wetland complex 

into Lake Michigan by as much as 85 and 75 percent, respectively. Dissolved phosphorous concentrations decreased across 

the SUIBSP by about 60 percent, but spatial patterns in phosphorous concentrations in the northern part of the study area 

are not clear. The ponds and wetlands appear to be trapping 

sediment in the water moving through the wetland complex, 

particularly during storm events. These reductions are the 

result of various processes that occur in the coastal complex 

that differ by type of contaminant. These processes include 

dilution, transformations by microbes, uptake by plants, 

adsorption onto sediments, and deposition.

Groundwater levels associated with the various plant 

communities in SBNP, CPSNA, NUIBSP, and SUIBSP show 

that hydroperiods in each community type were similar but 

that average hydroperiods were distinct for each community 

type. Emergent marsh wetlands often had more than 1 foot of 

standing water with little or no time when water levels were 

below land surface. Sedge meadows were the second wettest 

community, with shallow standing water for months in winter 

to early summer and water levels slightly below land surface 

for the remainder of the year, allowing propagation of sedge 

species. Wet prairies were slightly less wet, with highest water 

levels at or slightly above land surface for a few weeks in the 

late winter to late spring, with levels falling off dramatically in 

the summer. Water levels in wet-mesic and mesic prairies generally did not rise above land surface or did so only temporarily, and were well below land surface for much of the year. 

Hydroperiods of emergent marsh communities containing 

Typha spp. were similar to the hydroperiod of the emergent 

marsh that lacked Typha spp., most likely indicating that the 

hydroperiods have already been altered, but there may be a 

time lag between the hydrologic alteration and the colonization by Typha spp. of all available habitats. Therefore, areas 

of emergent marsh in the coastal complex where invasive 

species have not been observed, such as the monitored part of 

the CPSNA, may be areas that are farther from the Typha spp.

point of origin that will eventually be colonized. High concentrations of dissolved solids in the water also may be promoting 

the spread of invasive species, especially because they derive 

from the same factors that altered the hydrology. However, 

Typha spp. and other invasive species will likely spread even 

to emergent wetland areas of lower specific conductance. In 

addition, other factors not addressed in this investigation may 

influence the distribution of Typha spp., such as land management, disturbance history, and watershed-level alterations.

Groundwater and surface-water levels in wetlands were 

strongly associated with plant-species diversity and occurrence in the study area. Anecdotal evidence from long-term 

residents and land managers, as well as the presence of 

submerged sedge tussocks, indicate that water levels in the 

SBNP have increased through time. Although this study does 

not definitively demonstrate whether such changes have taken 

place, it is a supportable assumption. Analysis of the data 

collected during this investigation indicates that the construction of roadbeds, berms, storm drains, and other structures, 

along with potential increases in the volume and rate of runoff, 

likely have increased the volume of water entering the SBNP 

and decreased the rate at which water exits the SBNP relative to natural conditions. Culverts, ditches, and drains were 

installed to help drain the site, but at least some of these features are no longer functional or have clogged. The resultant 

ponding likely has expanded the extent of emergent marsh 

communities, and may have allowed Typha spp. to expand at 

the expense of other types of wetland plants. Given that the 

specific conductance of surface waters is also correlated with 

Typha spp. abundance and that runoff quality was found to 

contain indicators of the agricultural and urban land use in 

the watershed, both the quality and quantity of runoff are a 

prime concern for the long-term viability of the natural plant 

communities in the study area. Sampling of a larger number of 

sites and for a larger suite of water-quality constituents would 

be more definitive when comparing the potential effects of 

increased inundation from onsite hydrologic alterations relative to the effects of the water quality of the runoff entering 

the site.

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Glossary 63

Glossary

average wetness A measure of the affiliation of a plant 

community for wet conditions, made by quantifying and averaging the indicator status of plants, as discussed in the U.S. 

Army Corps of Engineers Wetland Delineation Manual.

coefficient of conservatism An estimate of the degree to 

which a species has a high tendency to occur only in a specific 

habitat type. The scores are mainly reflective of a plant’s 

susceptibility to ecological change, with 0 being minimally 

susceptible and 10 being highly susceptible.

dry, mesic, wet (and combinations) prairie Prairies are communities dominated by grasses on organic or mineral soils. 

Trees may be present, but less than 10 percent of the area has 

tree cover. Dry prairies have a high density of herbaceous 

flowering plants and low percentage of grass cover. Mesic 

prairie is a native grassland community dominated by big 

bluestem, little bluestem, and Indian grass (Sorghastrum 

nutans) that occurs on loam, sandy loam or silt loam soils on 

level or slightly undulating glacial outwash. Wet prairie is an 

herbaceous wetland typically dominated by graminoid species 

such as prairie cordgrass, bluejoint, and sedges. Vegetation 

height is often 6–9 ft. Wet prairies occur in deep swales, and 

the substrate ranges from very deep black mineral soils (which 

are high in organic matter) to muck. Ponding in spring lasts for 

several weeks prior to drainage. 

dune and swale An ecological system consisting of a 

mixture of upland and wetland natural communities. These 

communities occur in long, narrow, linear complexes, with the 

dry communities occupying sand ridges and the wet communities occurring in the intervening swales. Trees and prairie 

vegetation typically occur on the ridges, and sedges, reeds, and 

marsh/aquatic vegetation line are found in the swales. Water 

levels are directly influenced by groundwater, with the interdunal swales controlled largely by lateral flow through porous 

beach ridges. 

emergent marsh Cyclical wetland dominated by emergent 

reeds and grasses and other aquatic plants. Vegetation and 

wildlife composition varies spatially with water depth. The 

stages of the marsh cycle form a continuum from a ponded 

state—in which open water covers all but the marsh’s shallow 

edges—to a closed, 100-percent cover by emergent vegetation. Maximum structural diversity of importance for wetland 

birds is reached where the surface is approximately 50 percent 

open water and 50 percent emergent vegetation. This is called 

the hemi-marsh stage, and in it these two structural features 

are completely interspersed to maximize the internal interface 

between water and vegetation. 

eutrophication The process by which lakes gradually age 

and become more productive due to an increase in compounds 

containing nitrogen or phosphorus. An increase in the lake’s 

primary productivity is accompanied by excessive plant 

growth and decay, which can have further effects including 

lack of oxygen and severe reductions in water quality, fish, and 

other animal populations.

fen A calcareous, groundwater-fed wetland typically located 

in the vicinity of glacial moraines and containing a muck or 

peat substrate. Fens support many plants adapted to high concentrations of dissolved alkaline minerals. 

floristic quality (assessment index) A statistic designed to 

reduce subjectivity and create a standard means of expressing 

vegetation quality that may be used to compare sites and to 

assess the quality of a site through time. Often used to assess 

the degree to which a site has been impacted by human disturbance. The index is the mean coefficient of conservatism times 

the square root of the total number of native species at a site.

foredune A coastal dune or ridge that is parallel to the shoreline of a large lake or ocean and is stabilized by vegetation.

hydroperiod A measure of the depth and duration of inundation or saturation as measured above or below a given 

datum; often depicted as a graphic of surface or groundwater 

levels through time at a given point relative to land surface or 

summed to make a value of inundation or saturation at a given 

location. 

importance value A measure of the relative dominance of 

a species in an ecological community. Importance values rank 

species within an area on the basis of how commonly a species 

occurs across the entire community, the total number of individuals of the species, and the total amount of area occupied 

by the species. 

inundation duration Period of time in which a given area 

contains standing water.

panne Groundwater-fed interdunal wetland occupying 

calcareous, moist sands of the lake plain, generally within 1 

mile of Lake Michigan. Sedges and sedge relatives dominate 

this open-structured wetland, which has considerable floristic 

overlap with fens and calcareous seeps.

quadrat A rectangle or square of known dimensions typically used by ecologists to define an area within which the 

number and type of vegetation is counted.

residence time Average time water spends in a specified 

region of space. For purposes of this report, residence time 

refers to the amount of time surface water spends in the various parts of the wetland complex.
64 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

sand prairie Herbaceous wetland typically dominated by 

graminoid species such as prairie cordgrass, bluejoint, and 

sedges with a sand substrate. Flooding is a regular springtime 

occurrence and may last several weeks. 

sand savannah Grassland region with scattered trees, grading into either open plain or woodland with a sand substrate.

sedge meadows Sedge-dominated grasslands that include 

wet-prairie grasses. Groundwater seepage and/or shallow 

flooding are the principal hydrological factors, and frequent 

fire is needed to retain sedge meadows’ open structure. Sedge 

meadows often grade into fens, marshes, or wet prairies.

species richness index A measurement of the total number 

of species present in an ecosystem. 

specific yield A ratio, less than or equal to the effective 

porosity, indicating the volumetric fraction of the bulk aquifer 

volume that a given aquifer will yield when all the water is 

allowed to drain out of it under the forces of gravity. Value is 1 

for surface-water bodies.

suspended sediment Particulate organic and inorganic matter suspended in or carried by water.

tussock A compact tuft, especially of sedge or grass.

upland prairie Topographically elevated ecosystem dominated by herbaceous plants other than grasses or sedges on 

moderately well drained to excessively drained soils. 
Appendix 1. Water-Level Measurements in 

the Vicinity of Spring Bluff Nature Preserve, 

Lake County, Illinois 
Table 1–1. Water-level elevation at gages and in wells in the vicinity of Spring Bluff Nature Preserve, Lake County, Illinois. [nm, not measured; bold denotes ice present; underline denotes gage is dry, value is maximum possible water level; *, flow on river at gage DR3; bold and underline denotes gaminimum possible water level]

Gage 

or well

Elevation 

of top of 

casing 

(feet)

Elevation 

of land 

surface 

(feet)

Water-level elevation, in feet above North American Vertical Datum of 1988, on given 

07/24/2007 07/26/2007 08/20/2007 08/23/2007 09/11/2007 09/18/2007 10/18/2007 10/29/2007 11/08/20

Gage B 589.34 585.34 nm nm 586.54 586.80 586.00 585.77 585.77 585.71 585.4

Well 1 588.98 585.32 584.53 584.39 586.54 586.72 585.98 585.76 585.77 585.70 585.4

Well 2 591.75 588.51 nm nm 586.51 586.79 585.95 585.59 585.52 nm nm 

Well 3 589.37 585.24 584.20 584.08 586.57 586.80 585.99 585.63 585.46 585.29 585.0

Well 4 591.42 588.70 nm nm 586.57 586.80 585.78 585.39 585.08 nm nm 

Well 5 588.92 584.88 583.57 583.46 586.68 586.73 585.60 585.22 584.60 584.17 583.9

Gage C 588.84 584.81 nm nm 586.68 586.79 585.60 585.21 nm nm nm 

Well 6 593.88 589.98 587.96 587.87 589.55 589.64 589.27 588.91 589.24 589.06 588.9

Gage D 593.02 589.07 nm nm 589.15 589.22 nm nm nm nm 

Well 7 592.97 589.05 587.04 586.92 589.18 589.18 588.80 588.46 588.38 588.70 588.5

Well 8 593.11 589.12 nm nm 588.65 588.68 588.05 587.66 588.15 588.01 587.9

Well 9 591.13 587.46 586.02 585.89 588.24 588.15 587.77 587.52 587.85 587.77 587.6

Gage E 591.23 587.19 nm nm 588.26 588.33 587.79 587.53 587.87 587.89 587.7

Well 10 592.20 588.30 nm nm 588.25 587.22 587.75 587.45 587.87 587.77 587.6

Well 11 592.88 588.86 nm nm 588.28 587.52 587.29 587.84 587.68 587.5

Gage F 589.51 585.51 nm nm 589.21 588.21 587.47 587.18 588.41 587.54 587.3

Well 12 590.08 585.79 585.83 585.73 588.25 588.15 587.52 587.22 587.82 588.04 587.4

Well 13 592.59 588.65 nm nm 587.59 587.77 587.11 586.37 587.27 587.03 586.9

Well 14 590.41 586.62 585.83 585.69 586.98 587.12 586.68 586.16 586.82 586.70 586.6

Gage G 590.49 586.54 nm nm 586.99 587.14 586.67 nm 586.81 586.67 586.6

Well 15 592.59 588.50 nm nm 587.21 587.20 586.61 nm 586.65 586.40 586.2

Well 16 590.84 586.91 584.56 584.41 587.48 587.55 586.48 585.76 586.45 586.02 585.8

Well 17 591.37 588.33 nm nm 586.99 587.09 586.11 585.54 585.84 585.49 585.2

Well 18 589.18 585.41 584.23 584.10 586.90 586.90 586.04 585.54 585.75 585.45 585.1

Gage H 589.46 585.47 nm nm 586.88 586.90 586.02 585.54 585.74 nm nm 

Well 19 586.98 583.10 nm nm nm nm nm nm nm nm 580.9

Well 20 587.99 584.00 nm nm nm nm nm nm nm nm 583.5

Well 21 587.30 583.41 nm nm nm nm nm nm nm nm 583.5

Gage A 587.37 583.21 nm nm nm nm nm nm nm nm 583.5

Well 22 587.55 583.61 nm nm nm nm nm nm nm nm 583.5
Table 1–1. Water-level elevation at gages and in wells in the vicinity of Spring Bluff Nature Preserve, Lake County, Illinois. —Continued[nm, not measured; bold denotes ice present; underline denotes gage is dry, value is maximum possible water level; *, flow on river at gage DR3; bold and underline denotes gaminimum possible water level]

Gage 

or well

Elevation 

of top of 

casing 

(feet)

Elevation 

of land 

surface 

(feet)

Water-level elevation, in feet above North American Vertical Datum of 1988, on given 

11/27/2007 12/06/2007 12/14/2007 12/19/2007 12/31/2007 01/09/2008 01/22/2008 02/13/2008 03/13/20

Gage B 589.34 585.34 nm nm nm nm nm 586.10 nm nm nm 

Well 1 588.98 585.32 585.20 nm nm nm nm 586.08 nm nm 586.7

Well 2 591.75 588.51 nm nm 585.42 585.40 585.74 586.05 586.04 nm 586.7

Well 3 589.37 585.24 584.68 585.03 585.31 nm nm 586.13 nm nm 586.7

Well 4 591.42 588.70 nm nm nm nm 585.33 586.04 585.85 nm 586.7

Well 5 588.92 584.88 583.61 583.93 584.14 583.99 584.81 586.02 nm nm 586.7

Gage C 588.84 584.81 nm nm nm nm nm 586.02 nm nm 584.8

Well 6 593.88 589.98 589.05 589.27 589.30 589.57 589.36 589.47 nm 589.50 589.3

Gage D 593.02 589.07 nm 589.22 nm 589.16 589.10 589.12 nm nm nm 

Well 7 592.97 589.05 588.67 588.93 589.06 589.01 589.12 589.17 nm nm nm 

Well 8 593.11 589.12 587.97 588.22 588.36 588.28 588.35 588.53 nm 588.85 nm 

Well 9 591.13 587.46 587.73 587.93 nm nm 588.01 588.11 nm nm nm 

Gage E 591.23 587.19 587.73 587.89 587.97 587.93 587.98 588.09 nm nm nm 

Well 10 592.20 588.30 587.65 587.91 587.98 587.92 587.96 588.12 587.87 nm nm 

Well 11 592.88 588.86 587.45 587.90 588.01 587.91 588.00 588.17 587.57 589.13 nm 

Gage F 589.51 585.51 587.27 587.85 nm nm nm 588.09 587.75 nm nm 

Well 12 590.08 585.79 587.31 nm nm nm nm 588.12 nm nm nm 

Well 13 592.59 588.65 587.05 587.27 587.35 587.27 587.31 587.52 587.15 587.61 587.8

Well 14 590.41 586.62 586.74 nm nm 586.80 nm 586.97 nm nm nm 

Gage G 590.49 586.54 586.69 nm nm 586.87 nm 586.97 nm nm nm 

Well 15 592.59 588.50 586.36 586.64 586.75 586.66 586.85 587.11 586.68 586.99 587.2

Well 16 590.84 586.91 585.91 586.44 586.63 586.49 587.19 nm nm 587.5

Well 17 591.37 588.33 585.27 585.80 586.04 585.95 586.44 586.70 586.13 586.46 587.0

Well 18 589.18 585.41 585.19 585.71 nm nm nm 586.63 nm nm 586.8

Gage H 589.46 585.47 nm 585.72 585.95 585.94 nm 586.60 nm nm nm 

Well 19 586.98 583.10 580.80 581.15 581.21 581.20 581.69 581.84 581.58 nm 582.7

Well 20 587.99 584.00 583.60 nm 583.68 nm nm nm nm nm nm 

Well 21 587.30 583.41 583.52 nm 583.53 nm nm nm nm nm nm 

Gage A 587.37 583.21 583.51 nm nm nm nm nm 587.03 nm 583.3

Well 22 587.55 583.61 583.50 nm 583.56 nm nm nm 583.81 nm 584.0
Table 1–1. Water-level elevation at gages and in wells in the vicinity of Spring Bluff Nature Preserve, Lake County, Illinois. —Continued[nm, not measured; bold denotes ice present; underline denotes gage is dry, value is maximum possible water level; *, flow on river at gage DR3; bold and underline denotes gawas submerged, value is minimum possible water level]

Gage 

or well

Elevation 

of top of 

casing 

(feet)

Elevation 

of land 

surface 

(feet)

Water-level elevation, in feet above North American Vertical Datum of 1988, on given date

03/26/2008 04/09/2008 04/29/2008 05/05/2008 05/13/2008 06/05/2008 06/11/2008 07/07/2008 08/27/20

Gage B 589.34 585.34 587.02 586.96 587.74 586.54 586.42 586.34 nm 586.31 nm

Well 1 588.98 585.32 587.03 586.95 587.75 586.54 586.43 586.35 nm 586.30 584.7

Well 2 591.75 588.51 587.02 586.95 586.55 586.52 586.38 586.31 nm 586.24 nm

Well 3 589.37 585.24 586.99 586.92 586.55 586.50 586.39 586.32 nm 586.26 584.7

Well 4 591.42 588.70 587.02 586.92 586.50 586.43 586.30 586.26 nm 586.15 nm

Well 5 588.92 584.88 587.03 585.96 586.48 586.36 586.21 586.14 nm 586.05 584.2

Gage C 588.84 584.81 586.80 586.85 586.45 586.36 586.19 586.12 nm 586.01 nm

Well 6 593.88 589.98 589.30 589.35 589.22 589.19 589.50 589.67 nm 589.48 587.9

Gage D 593.02 589.07 589.20 589.19 589.10 589.09 nm 589.12 nm nm nm

Well 7 592.97 589.05 589.92 589.91 589.82 589.78 589.80 589.84 nm 589.67 587.7

Well 8 593.11 589.12 nm 588.56 588.34 588.29 588.37 588.52 nm 588.22 nm

Well 9 591.13 587.46 588.29 588.31 588.11 588.06 588.02 588.03 nm 587.91 585.9

Gage E 591.23 587.19 588.27 588.30 588.09 588.08 588.01 588.03 nm 587.88 nm

Well 10 592.20 588.30 588.20 588.23 588.02 588.00 587.93 587.98 nm 587.81 nm

Well 11 592.88 588.86 nm 589.32 589.03 589.03 589.01 587.07 nm 588.86 nm

Gage F 589.51 585.51 588.27 588.26 587.85 587.85 587.76 587.77 nm 587.51 nm

Well 12 590.08 585.79 588.22 587.22 587.81 587.78 587.72 587.72 nm 587.58 585.4

Well 13 592.59 588.65 586.76 587.74 587.28 587.27 587.22 587.69 nm 587.33 nm

Well 14 590.41 586.62 587.13 587.16 586.91 586.89 586.90 586.98 nm 586.80 585.0

Gage G 590.49 586.54 587.14 586.56 586.91 586.92 586.89 586.99 nm 586.76 nm

Well 15 592.59 588.50 587.23 587.24 586.81 586.78 586.72 586.98 nm 586.69 nm

Well 16 590.84 586.91 587.51 587.50 586.93 586.89 586.70 586.87 nm 586.53 nmWell 17 591.37 588.33 587.06 587.01 586.61 586.62 586.50 586.57 nm 586.26 nm

Well 18 589.18 585.41 586.94 586.89 586.65 586.62 586.51 586.24 nm 586.18 584.4Gage H 589.46 585.47 588.00 588.06 588.30 588.32 588.44 588.70 nm 588.83 nm

Well 19 586.98 583.10 583.30 583.37 583.29 583.27 583.91 nm 583.33 582.88 581.2Well 20 587.99 584.00 584.88 583.84 583.77 583.75 583.74 nm 583.79 583.85 583.2

Well 21 587.30 583.41 583.74 583.59 583.57 583.55 583.57 nm 583.59 583.65 583.3

Gage A 587.37 583.21 583.74 583.55 583.54 583.53 583.53 nm 583.54 583.59 nmWell 22 587.55 583.61 583.82 583.75 583.69 583.68 583.68 nm 583.74 583.74 583.3
Table 1–2. Depth to water at gages and in wells in the vicinity of Spring Bluff Nature Preserve, Lake County, Illinois. [nm, not measured; bold denotes ice present; underline denotes gage is dry, value is maximum possible water level; *, flow on river at gage DR3; bold and underline denotes ga

minimum possible water level]

Gage 

or well

Elevation 

of top of 

casing 

(feet)

Elevation 

of land 

surface 

(feet)

Depth to water in feet above (negative value) and below (positive value) land surface on g

07/25/2007 07/27/2007 08/21/2007 08/24/2007 09/12/2007 09/19/2007 10/19/2007 10/30/2007 11/09/20

Gage B 589.34 585.34 nm nm -1.20 -1.46 -0.66 -0.43 -0.43 -0.37 -0.1

Well 1 588.98 585.32 0.78 0.92 -1.23 -1.41 -0.67 -0.45 -0.46 -0.38 -0.1

Well 2 591.75 588.51 0.00 0.00 2.00 1.72 2.56 2.92 2.99 nm nm 

Well 3 589.37 585.24 1.04 1.16 -1.33 -1.56 -0.75 -0.39 -0.22 -0.05 0.2

Well 4 591.42 588.70 0.00 0.00 2.13 1.90 2.92 3.31 3.62 nm nm 

Well 5 588.92 584.88 1.30 1.41 -1.80 -1.85 -0.73 -0.35 0.27 0.70 0.9

Gage C 588.84 584.81 0.00 0.00 -1.84 -1.95 -0.76 -0.37 nm nm nm 

Well 6 593.88 589.98 2.01 2.10 0.42 0.33 0.70 1.06 0.73 0.91 0.9

Gage D 593.02 589.07 nm nm -0.13 -0.20 0.00 nm nm nm nm 

Well 7 592.97 589.05 2.02 2.14 -0.12 -0.12 0.26 0.60 nm 0.36 0.5

Well 8 593.11 589.12 0.00 0.00 0.48 0.45 1.08 1.47 0.98 1.12 1.2

Well 9 591.13 587.46 1.44 1.57 -0.79 -0.70 -0.32 -0.07 -0.40 -0.32 -0.2

Gage E 591.23 587.19 nm nm -1.03 -1.10 -0.56 -0.30 -0.64 -0.66 -0.4

Well 10 592.20 588.30 nm nm 0.05 1.08 0.55 0.85 0.43 0.53 0.6

Well 11 592.88 588.86 nm nm nm 0.57 1.33 1.56 1.01 1.17 1.3

Gage F 589.51 585.51 nm nm nm -2.70 -1.96 -1.67 -2.90 -2.03 -1.8

Well 12 590.08 585.79 -0.04 0.06 -2.46 -2.36 -1.73 -1.43 -2.03 nm -1.6

Well 13 592.59 588.65 nm nm 1.05 0.88 1.54 2.28 1.38 1.62 1.6

Well 14 590.41 586.62 0.79 0.93 -0.36 -0.50 -0.06 0.46 -0.20 -0.08 -0.0

Gage G 590.49 586.54 nm nm -0.50 -0.65 -0.18 nm -0.32 -0.18 -0.1

Well 15 592.59 588.50 nm nm 1.29 1.30 1.89 nm 1.85 2.10 2.2

Well 16 590.84 586.91 2.35 2.50 -0.57 -0.64 0.43 1.15 0.46 0.89 1.0

Well 17 591.37 588.33 nm nm 1.34 1.24 2.22 2.79 2.49 2.84 3.1

Well 18 589.18 585.41 1.18 1.31 -1.49 -1.49 -0.63 -0.13 -0.34 -0.04 0.2

Gage H 589.46 585.47 nm nm -1.42 -1.44 -0.56 -0.08 -0.28 nm nm 

Well 19 586.98 583.10 nm nm nm nm nm nm nm nm 2.1

Well 20 587.99 584.00 nm nm nm nm nm nm nm nm 0.4

Well 21 587.30 583.41 nm nm nm nm nm nm nm nm -0.1

Gage A 587.37 583.21 nm nm nm nm nm nm nm nm -0.1

Well 22 587.55 583.61 nm nm nm nm nm nm nm nm 0.0
Table 1–2. Depth to water at gages and in wells in the vicinity of Spring Bluff Nature Preserve, Lake County, Illinois. —Continued[nm, not measured; bold denotes ice present; underline denotes gage is dry, value is maximum possible water level; *, flow on river at gage DR3; bold and underline denotes ga

minimum possible water level]

Gage 

or well

Elevation 

of top of 

casing 

(feet)

Elevation 

of land 

surface 

(feet)

Depth to water in feet above (negative value) and below (positive value) land surface on g

11/28/2007 12/07/2007 12/15/2007 12/20/2007 01/01/2008 01/10/2008 01/23/2008 02/14/2008 03/14/20

Gage B 589.34 585.34 nm nm nm nm nm -0.76 nm nm nm 

Well 1 588.98 585.32 0.11 nm nm nm nm -0.77 nm nm -1.4

Well 2 591.75 588.51 nm nm 3.09 3.11 2.77 2.46 2.47 nm 1.7

Well 3 589.37 585.24 0.56 0.21 -0.07 nm nm -0.89 nm nm -1.4

Well 4 591.42 588.70 nm nm nm nm 3.37 2.66 2.85 nm 1.9

Well 5 588.92 584.88 1.26 0.94 0.73 0.88 0.06 -1.14 nm nm -1.8

Gage C 588.84 584.81 nm nm nm nm nm -1.18 nm nm nm 

Well 6 593.88 589.98 0.92 0.70 0.67 0.40 0.61 0.50 nm 0.47 0.6

Gage D 593.02 589.07 nm -0.20 nm -0.14 -0.08 -0.10 nm nm nm 

Well 7 592.97 589.05 0.39 0.13 nm 0.05 -0.06 -0.11 nm nm nm 

Well 8 593.11 589.12 1.16 0.91 0.77 0.85 0.78 0.60 nm 0.28 nm 

Well 9 591.13 587.46 -0.28 -0.48 nm nm -0.56 -0.66 nm nm nm 

Gage E 591.23 587.19 -0.50 -0.66 -0.74 -0.70 -0.75 -0.86 nm nm nm 

Well 10 592.20 588.30 0.65 0.39 0.32 0.38 0.34 0.18 0.43 nm nm 

Well 11 592.88 588.86 1.40 0.95 0.84 0.94 0.85 0.68 1.28 -0.28 nm 

Gage F 589.51 585.51 -1.76 -2.34 nm nm nm -2.58 -2.24 nm nm 

Well 12 590.08 585.79 -1.52 nm nm nm nm -2.33 nm nm nm 

Well 13 592.59 588.65 1.60 1.38 1.30 1.38 1.34 1.13 1.50 1.04 0.8

Well 14 590.41 586.62 -0.12 nm nm -0.18 nm -0.35 nm nm nm 

Gage G 590.49 586.54 -0.20 nm nm -0.38 nm -0.48 nm nm nm 

Well 15 592.59 588.50 2.14 1.86 1.75 1.84 1.65 1.39 1.82 1.51 1.2

Well 16 590.84 586.91 1.00 0.47 0.28 0.42 nm -0.28 nm nm -0.6

Well 17 591.37 588.33 3.06 2.53 2.29 2.38 1.89 1.63 2.20 1.88 1.2

Well 18 589.18 585.41 0.22 -0.30 nm nm nm -1.22 nm nm -1.4

Gage H 589.46 585.47 nm -0.26 -0.49 -0.48 nm -1.14 nm nm nm 

Well 19 586.98 583.10 2.30 1.95 1.89 1.90 1.41 1.26 1.52 nm 0.3

Well 20 587.99 584.00 0.40 nm 0.32 nm nm nm nm nm nm 

Well 21 587.30 583.41 -0.11 nm -0.12 nm nm nm nm nm nm 

Gage A 587.37 583.21 -0.14 nm nm nm nm nm nm nm nm 

Well 22 587.55 583.61 0.10 nm 0.04 nm nm nm nm nm -0.4
Table 1–2. Depth to water at gages and in wells in the vicinity of Spring Bluff Nature Preserve, Lake County, Illinois. —Continued[nm, not measured; bold denotes ice present; underline denotes gage is dry, value is maximum possible water level; *, flow on river at gage DR3; bold and underline denotes gasubmerged, value is minimum possible water level]

Gage 

or well

Elevation 

of top of 

casing 

(feet)

Elevation 

of land 

surface 

(feet)

Depth to water in feet above (negative value) and below (positive value) land surface on given date

03/27/2008 04/10/2008 04/30/2008 05/06/2008 05/14/2008 06/06/2008 06/12/2008 07/08/2008 08/28/20

Gage B 589.34 585.34 -1.68 -1.62 -2.40 -1.20 -1.08 -1.00 nm -0.97 nm

Well 1 588.98 585.32 -1.72 -1.64 0.00 -1.22 -1.12 -1.04 nm -0.98 0.5

Well 2 591.75 588.51 1.49 1.56 1.96 2.00 2.13 2.20 nm 2.27 nm

Well 3 589.37 585.24 -1.75 -1.68 -1.31 -1.26 -1.15 -1.08 nm -1.02 0.4

Well 4 591.42 588.70 1.68 1.78 2.20 2.26 2.40 2.44 nm 2.55 nm

Well 5 588.92 584.88 -2.15 nm -1.60 -1.49 -1.33 -1.26 nm -1.18 0.6

Gage C 588.84 584.81 -1.96 -2.01 -1.61 -1.52 -1.35 -1.28 nm -1.17 nm

Well 6 593.88 589.98 0.68 0.63 0.76 0.79 0.48 0.31 nm 0.50 2.0

Gage D 593.02 589.07 -0.18 -0.17 -0.08 -0.07 nm -0.10 nm nm nm

Well 7 592.97 589.05 -0.86 -0.85 -0.76 -0.72 -0.74 -0.78 nm -0.61 1.3

Well 8 593.11 589.12 nm 0.57 0.79 0.83 0.76 0.61 nm 0.90 nm

Well 9 591.13 587.46 -0.83 -0.85 -0.65 -0.60 -0.56 -0.57 nm -0.45 1.5

Gage E 591.23 587.19 -1.04 -1.07 -0.86 -0.85 -0.78 -0.80 nm -0.65 nm

Well 10 592.20 588.30 0.11 0.08 0.29 0.31 0.38 0.33 nm 0.49 nm

Well 11 592.88 588.86 nm -0.47 -0.18 -0.17 -0.16 1.78 nm -0.01 nm

Gage F 589.51 585.51 -2.76 -2.75 -2.34 -2.34 -2.25 -2.26 nm -2.00 nm

Well 12 590.08 585.79 -2.42 nm -2.01 -1.99 -1.92 -1.92 nm -1.79 0.3

Well 13 592.59 588.65 1.89 0.91 1.37 1.38 1.43 0.96 nm 1.32 0.0

Well 14 590.41 586.62 nm nm -0.29 -0.27 -0.28 -0.36 nm -0.17 1.6

Gage G 590.49 586.54 -0.65 -0.07 -0.42 -0.43 -0.40 -0.50 nm -0.27 nm

Well 15 592.59 588.50 1.27 1.26 1.69 1.72 1.78 1.52 nm 1.81 nm

Well 16 590.84 586.91 -0.60 -0.59 -0.02 0.02 0.21 0.04 nm 0.38 nmWell 17 591.37 588.33 1.28 1.33 1.73 1.72 1.84 1.77 nm 2.07 nm

Well 18 589.18 585.41 -1.53 -1.48 -1.24 -1.21 -1.10 -0.83 nm -0.76 1.0Gage H 589.46 585.47 -1.46 -1.40 -1.16 -1.14 -1.02 -0.76 nm -0.63 nm

Well 19 586.98 583.10 -0.20 -0.27 -0.19 -0.17 nm nm -0.23 0.22 1.8Well 20 587.99 584.00 nm 0.16 0.23 0.25 0.26 nm 0.21 0.15 0.7

Well 21 587.30 583.41 -0.33 -0.18 -0.16 -0.14 -0.16 nm -0.18 -0.24 0.1

Gage A 587.37 583.21 -0.37 -0.18 -0.17 -0.16 -0.16 nm -0.17 -0.22 nmWell 22 587.55 583.61 -0.21 -0.14 -0.08 -0.07 -0.07 nm -0.13 -0.13 0.2
72 Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008

Table 1–3. Water-level elevation at gages and in wells in the vicinity of Spring Bluff Nature Preserve, Lake County, Illinois. 

[nm, not measured; bold denotes ice present; underline denotes gage is dry, value is maximum possible water level; *, flow on river at gage DR3; bold and 

underline denotes gage is submerged, value is minimum possible water level]

Gage Water-level elevation, in feet above North American Vertical Datum of 1988, on given date

05/25/2007 05/26/2007 06/01/2007 06/07/2007 06/09/2007 06/13/2007 06/15/2007 06/19/2007 06/21/2007 06/28/2007

W1 584.67 nm 584.60 585.23 586.72 585.28 584.87 584.60 584.73 584.41

DD1 nm 596.36 596.31 596.50 598.29 596.37 596.22 596.13 596.22 596.10

W3 588.41 nm 588.42 588.53 589.21 588.51 588.44 588.44 588.45 588.28

DD2 588.46 nm 588.46 588.57 589.13 588.55 588.47 588.37 nm 588.32

W2 585.62 nm 586.11 585.62 586.11 586.31 586.19 586.01 585.97 585.63

DD4 593.10 nm 593.10 nm 593.35 593.07 593.04 593.04 593.03 593.09

SG1 587.48 nm 587.48 588.09 588.52 588.22 588.09 587.78 588.09 587.48

W4 nm 585.67 585.68 585.76 586.29 585.98 585.86 585.74 585.77 585.67

DD3 582.00 nm 581.79 582.15 582.88 582.25 582.15 581.97 582.07 581.45

DR1 nm 592.27 592.28 592.50 594.49 592.53 592.42 592.38 592.42 592.37

DR2 nm 584.82 nm 584.93 585.38 584.85 584.70 584.76 584.81 584.78

DR3 580.28 nm 578.78 579.27 579.12 578.57 578.53 578.68 579.01 579.2

Gage Water-level elevation, in feet above North American Vertical Datum of 1988, on given date

06/30/2007 07/04/2007 07/06/2007 07/12/2007 07/14/2007 07/17/2007 07/20/2007 07/25/2007 07/27/2007 07/31/2007

W1 584.39 584.37 584.39 584.34 584.26 584.21 584.22 583.96 583.88 583.84

DD1 596.10 596.09 596.11 596.11 596.10 596.09 596.10 596.08 596.10 596.08

W3 588.28 588.22 588.23 588.19 587.93 587.78 587.76 587.47 587.35 587.27

DD2 588.27 588.15 588.26 588.07 587.98 587.82 587.80 587.50 587.43 587.35

W2 585.49 585.37 585.37 585.11 584.98 584.79 584.57 584.26 584.01 583.52

DD4 593.08 593.06 593.04 593.04 592.94 592.94 592.94 592.94 592.94 592.94

SG1 587.35 587.12 587.45 587.01 586.84 586.65 586.7 586.41 586.32 586.29

W4 585.63 585.53 585.58 585.39 585.24 585.07 585.07 584.79 584.71 584.73

DD3 581.40 581.40 581.40 581.40 581.40 581.40 581.40 581.40 581.40 581.40

DR1 592.36 592.33 592.36 592.36 592.32 592.32 592.33 592.3 592.31 592.13

DR2 584.74 584.71 584.70 584.72 584.66 584.62 584.61 584.51 584.50 584.54

DR3 580.33 580.3 580.49 579.98 579.86 579.66 579.65 579.45 579.43 579.73

Gage

Water-level elevation, in feet above North American Vertical Datum of 1988, on given date

08/21/2007 08/24/2007 08/30/2007 09/12/2007 09/19/2007 10/06/2007 10/19/2007 10/30/2007 11/09/2007 11/17/2007

W1 587.32 586.29 585.26 584.63 584.37 584.46 585.22 584.58 584.51 584.49

DD1 597.98 597.82 596.37 596.32 596.22 596.22 596.48 596.32 596.32 596.28

W3 589.08 588.88 588.45 588.20 588.02 588.36 588.48 588.35 589.17 588.20

DD2 589.12 588.9 588.49 588.22 588.06 588.39 588.52 588.39 588.27 588.24

W2 586.44 586.90 586.32 585.75 585.44 585.20 584.96 584.66 583.97 583.52

DD4 593.25 593.16 593.11 593.09 593.04 593.03 593.07 593.05 593.01 593.01

SG1 588.38 588.22 587.97 587.61 588.18 587.49 587.85 587.45 587.26 587.21

W4 586.27 586.19 585.96 585.73 585.66 585.72 585.77 585.81 585.75 585.71

DD3 582.85 582.76 582.13 581.40 581.40 581.40 581.40 581.40 581.40 581.40

DR1 593.94 593.35 592.41 592.41 592.2 592.25 592.31 592.24 592.27 592.27

DR2 585.33 585.16 584.83 584.79 584.61 584.47 584.71 584.55 584.45 584.37

DR3 579.43 578.75 578.5 579.94 579.76 580.24 580.18 580.42 580.32 580.22
Table 1–3 73

Table 1–3. Water-level elevation at gages and in wells in the vicinity of Spring Bluff Nature Preserve, Lake County, Illinois. 

—Continued

[nm, not measured; bold denotes ice present; underline denotes gage is dry, value is maximum possible water level; *, flow on river at gage DR3; 

bold and underline denotes gage is submerged, value is minimum possible water level]

Gage Water-level elevation, in feet above North American Vertical Datum of 1988, on given date

11/23/2007 11/28/2007 12/07/2007 12/15/2007 12/20/2007 01/01/2008 01/10/2008 01/23/2008 02/14/2008

W1 584.52 584.52 585.16 585.36 585.00 585.23 585.80 586.31 585.00

DD1 596.29 596.26 596.42 596.76 596.60 596.62 597.40 596.70 597.58

W3 588.22 589.10 588.94 588.68 588.66 588.99 588.46 588.26 588.60

DD2 588.26 588.34 588.58 588.64 588.62 588.68 588.66 588.5 588.74

W2 583.52 583.52 583.52 584.76 585.06 585.92 586.26 585.95 586.37

DD4 593.02 593.00 593.05 593.07 593.05 593.04 593.06 593.09 593.37

SG1 587.21 587.29 587.8 587.88 587.8 587.92 588.06 587.73 588.26

W4 585.73 586.62 586.57 585.97 585.97 586.04 586.21 586.07 586.53

DD3 581.40 581.40 581.40 581.40 581.40 582.10 582.53 582.30 581.40

DR1 592.32 592.32 592.29 592.51 592.31 592.45 592.99 592.51 592.71

DR2 584.37 584.39 584.71 584.68 584.52 584.64 584.84 584.64 584.82

DR3 580.25 580.02 581.00 578.00 577.84 577.97 578.26 578.04 578.72

Gage Water-level elevation, in feet above North American Vertical Datum of 1988, on given date

02/29/2008 03/14/2008 03/19/2008 03/27/2008 04/03/2008 04/10/2008 04/30/2008 05/14/2008 06/12/2008

W1 585.82 585.66 586.56 586.12 585.86 586.16 584.72 584.56 585.62

DD1 596.56 597.38 597.50 597.77 597.27 597.99 597.58 596.60 597.19

W3 588.64 588.58 591.66 588.67 588.50 588.62 588.16 588.12 588.37

DD2 589.06 588.78 588.6 588.71 588.54 588.65 588.22 588.19 588.41

W2 586.85 586.58 587.05 586.85 587.05 586.45 586.45 586.30 587.05

DD4 593.32 593.02 nm 593.06 593.04 592.87 592.92 593.03 593.02

SG1 588.2 588.14 nm 588.09 588.18 588.38 588.26 588.22 588.33

W4 586.77 586.87 586.80 586.79 586.58 586.39 586.12 586.06 586.26

DD3 581.40 582.37 nm 582.90 582.94 582.82 582.35 582.24 582.80

DR1 592.39 592.51 593.00 593.41 592.98 592.98 592.98 nm nm

DR2 584.90 585.14 585.00 585.27 584.92 585.15 584.75 584.82 584.87

DR3 578.88 577.82 nm 578.34 578.67 578.28 578.60 579.14 578.42
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Kay and others—Hydrology, Water Quality, and Changes in Vegetation, Spring Bluff Forest Preserve, Illinois, May 2007–August 2008—Scientific Investigations Report 2009–5237