~ V_o_lu_rn_e2_ • Water Resources
KISHWAUKEE RIvER AREA ASSESSMENT
':I ~EE OEP"nMHIT Of NATURAL RESOURCES KISHWAUKEE RIvER AREA ASSESSMENT
VOLUME2: WATER RESOURCES
D1inois Department ofNatural Resources Office of Scientific Research and Analysis Dlinois State Water Survey 2204 Griffith Drive Champaign, Dlinois 61820 (217) 244-5459
1998
300 Printed by the authority ofthe State ofDlinois Other CTAP Publications
The Changing Illinois Environment: Critical Trends • Summary Report • Volume 1: Air Resources • Volume 2: Water Resources ., Volume 3: Ecological Resources • Volume 4: Earth Resources • Volume 5: Waste Generation andManagement • Volume 6: Sources ofEnvironmental Stress • Volume 7: Bibliography RockRiver Area Assessment, technical report The RockRiver Country: An Inventory ofthe Region's Resources, general report Cache RiverArea Assessment, technical report The Cache River Basin: An Inventory ofthe Region's Resources, general report Mackinaw River Area A~sessment The Mackinaw River Country: An Inventory ofthe Region's Resources The Illinois Headwaters: An Inventory ofthe Region's Resources Headwaters Area Assessment, technical report The Illinois Big Rivers: An Inventory ofthe Region's Resources Big Rivers Area Assessment, technical report The Fox River Basin: An Inventory ofthe Region's Resources Fox River Area Assessment, technical report Annual Report 1996, Dlinois RiverWateh Stream Monitoring Manual, Dlinois RiverWateh PLAN-IT EARTH, FlOWing Waters Module PLAN-ITEARTH, ForestModule Forest Monitoring Manual, illinois ForestWateh . Illinois Land Cover, An Atlas, plus CD-ROM Inventory ofEcologically Resource-Rich Areas in Illinois Illinois Geographic Information System, CD-ROM ofdigital geospatial data
All CTAP and Ecosystems Program documents are available from the DNR Clearinghouse at (217) 782-7498 or TDD (217) 782-9175. Selected publications are also available on the World Wide Web at http://dnr.state.il.uslctap/ctaphome.htm, or http://dnr.state.i1.uslc2000/managelpartner.htm, as well as on the EcoForum Bulletin Board at I (800) 528-5486 or (217) 782-8447.
For more information about CTAP, call (217) 524-0500 or e-mail [email protected]; for information on the Ecosystems Program call (217) 782-7940 or e-rnail at [email protected]. About This Report
The Kishwaukee River Area Assessment examines an area spanning seven counties situated in the Kishwaukee River basin in northern DIinois. Because significant natural community and species diversity is found in the area, it has been designated a state Resource Rich Area.!
This report is part ofa series ofreports on areas ofDlinois where a public-private partnership has been formed. These assessments provide information on the natural and human resources ofthe areas as a basis for managing and improving their ecosystems. The determination of . resource rich areas and development ofecosystem-based information and management programs in Illinois are the result ofthree processes -- the Critical Trends Assessment Program, the Conservation Congress, and the Water Resources and Land Use Priorities Task Force.
Background
The Critical Trends Assessment Program (CTAP) documents changes in ecological conditions. In 1994, using existing information, the program provided a baseline of ecological conditions? Three conclusions were drawn from the baseline investigation:
1. the emission and discharge of regulated pollutants over the past 20 years has declined, in some cases dramatically, 2. existing data suggest that the condition ofnatural ecosystems in DIinois is rapidly decIining as a result offragmentation and continued stress, and 3. data designed to monitor compliance with environmental regulations or the status of individual species are not sufficient to assess ecosystem health statewide.
Based on these findings,CTAP has begun to develop methods to systematically monitor ecological conditions and provide information for ecosystem-based management. Five components make up this effort: .
1. identifY resource rich areas, 2. conduct regional assessments, 3. publish an atlas and inventory oflllinois landcover, 4. train volunteers to collect ecological indicator data, and 5. develop an educational science curriculum which incorporates data collection
1 See Inventory ofResource Rich Areas in Illinois: An Evaluation ofEcological Resources. 2 See The Changing Illinois Environment: Critical Trends, summmy report and volumes 1-7.
iii At the same time that CTAP was publishing its baseline findings, the TIlinois Conservation Congress and the Water Resources and Land Use Priorities Task Force were presenting their respective findings. These groups agreed with the CTAP conclusion that the state's ecosystems were declining. Better stewardship was needed, and they determined that a voluntary, incentive-based, grassroots approach would be the most appropriate, one that recognized the inter-relatedness ofeconomic development and natural resource protection and enhancement.
From the three initiatives was born Conservation 2000, a six-year program to begin reversing ecosystem degradation, primarily through the Ecosystems Program, a cooperative process of public-private partnerships that are intended to merge natural resource stewardship with economic and recreational development. To achieve this goal, the program will provide financial incentives and technical assistance to private landowners. The Rock River and Cache River were designated as the first Ecosystem Partnership areas.
At the same time, CTAP identified 30 Resource Rich Areas (RRAs) throughout the state. In RRAs where Ecosystem Partnerships have been formed, CTAP is providing an assessment of the area, drawing from ecological and socio-economic databases to give an overview ofthe region's resources -- geologic, edaphic, hydrologic, biotic, and socio-economic. Although several ofthe analyses are somewhat restricted by spatial and/or temporal limitations ofthe data, they help to identifY information gaps and additional opportUnities and constraints to establishing long-term monitoring programs in the partnership areas.
The Kishwaukee River Area Assessment
The Kishwaukee River Area Assessment covers an area ofapproxirnately 1,218 mile2 (779,744 acres) spanning seven counties in northern Illinois, including parts ofBoone, McHenry, Kane, DeKalb, and Ogle counties, and small parts ofLee and Winnebago counties. The boundaries ofthe assessment area coincide with the boundaries ofthe minois portion ofthe KishYiaukee River Basin, which is composed of22 subbasins identified by the Illinois Environmental ProtectionHoard. The mainstream ofthe Kishwaukee River empties into the Rock River three miles south ofRockford, illinois. It is formed by two branches which uRite below Cherry Valley. The North Branch rises in east-central MCHenry County and flows to the west. The South Branch has its origin on a moraine just north of Shabbona. It flows northeasterly to the village ofGenoa where it turns to the northwest. One ofthe subbasins, the Kishwaukee River (upper) totaling 64,386 acres, has been designated as a "Resource Rich Area" because it contains significant natural community diversity. The Kishwaukee River Ecosystem Partnership was subsequently formed around this core area ofhigh quality ecological resources.
This assessment is comprised offive volumes. In Volume 1, Geology discusses the .geology, soils, and minerals in the assessment area. Volume 2, Water Resources, discusses the surface and groundwater resources and Volume 3, Living Resources,
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Major Drainage Basins of lllinois and Location of the Kishwaukee River Assessment Area Scale 1:476200 I N I
Subbasins in the Kishwaukee River assessment area. Subbasin boundaries depicted are those determined by the Illinois Environmental Protection Agency. describes the natural vegetati'on communities and the fauna ofthe region. Volume 4 contains three parts: Part I, Socio-Economic Profile, discusses the demographics, infrastructure, and economy ofthe area, focusing on the four counties with the greatest amount ofland in the area -- Boone, DeKalb, McHenry and Winnebago counties; Part n, Environmental Quality, discusses air and water quality, and hazardous and toxic waste generation and management in the area; and Part m, ArchaeologicalResources, identifies and assesses the archaeological sites, ranging from the Paleoindian Prehistoric (B.C. 10,000) to Postwar (A.D. 1946), known in the assessment watershed. Volume S, Early Accounts ofthe Ecology ofthe Kishwaukee Area, describes the ecology ofthe area as recorded by historical writings ofexplorers, pioneers, early visitors and early historians.
vii
Contributors
Project Coordinator Nani Bhowmik
Maps : Robert Sinclair, Mark Varner
Editor Christopher Wellner
Introduction Rivers and Streams, Lakes, Physiography H. Vernon Knapp Wetiands , Michael Miller, Liane Suloway, Laura Keefer' Land Use : Laura Keefer
Climate and Trends in Climate James Angel, Wayne Armstrong
Streamflow H. Vernon Knapp, Gana Ramamurthy, Kenneth Nichols
Erosion and Sedimentation Misganaw Demissie, Renjie Xia, William Bogner
Water Use and Availability Ground-Water Resources Kenneth Hlinka, John Blomberg, Kay Charles Surface Water Resources : H. Vernon Knapp
Ground-Water Quality Kenneth Hlinka, John Blomberg, Thomas Holm
• Contributor Affiliations: Michael Miller, Illinois State Geological Survey; Liane Suloway, Illinois Natural . History Survey; Laura Keefer, lllinois State Water Survey.
ix
Table of Contents
Introduction I Rivers and Streams I Lakes : 3 Wetlands 3 Physiography 8 Land Use : 9 Climate and Trends in Climate 11 Temperature 1I Precipitation 14 Precipitation Deficits and Excesses 18 Severe Weather , 18 Tornadoes , I8 Hail 19 Thunderstonns 19 Summary 20 Streamflow 21 Stream Gaging Records 21 Human Impacts on StreamfIows in the Basin 21 Annual Streamflow Variability 23 Statistical Trend Analysis 24 Geographic Flow Variability 25 Seasonal Flow Variability 26 Flooding and High Flows 27 Drought and Low Flows : 28 Temporal Trends in Low Flows 29 Summary 31 Erosion and Sedimentation : 33 Instream Sediment Load , 33 Sedimentation 56 Water Use and Availability 57 Ground-Water Resources 57 Data Sources 58 Data Limitations 58 Ground-Water Availability 59 1995 Ground-Water Use 59 Ground-Water Use Trends 60 Surface Water Resources 61 Water Supply Use 61 Potential for Development of Additional Surface Water Sources 62
xi Ground-Water Quality 63 Data Sources 63 Data Limitations 64 Chemical Components Selected for Trend Analysis ; 65 Aquifer Unit Analysis 66 Discussion and Results : 66 Iron (Fe)...... •...... •....•..'" ...•...... 69 Total Dissolved Solids (TDS) 69 Sulfate (S04) 69 Nitrate (N03) : 70 Chloride 70 . Hardness (as CaC03) 70 Sumrnary 70 References 73
List of Figures Introduction Figure 1. Rivers, Streams, and Lakes in the Kishwaukee River Basin 2 Figure 2. Wetlands from the National Wetlands Inventory and Quadrangle Map Boundaries for the Kishwaukee River Assessment Area 6 Figure 3. National Wetlands Inventory Information from the Cherry Valley 7.5-Minute Quadrangle Map Showing Wetlands, Deepwater Habitats, and NWI Codes 7 Figure 4. Acreages of Selected Crops in the Kishwaukee River Basin Based on lAS Data 10
Climate and Trends in Climate Figure 5. Average Annual Temperature for Marengo, 1901-1996 12 Figure 6. Annual Number of Days with Maximum Temperatures Equal to or Above 90°F at Marengo, 1901-1996 13 Figure 7. Annual Number of Days with Minimum Temperatures Equal to or Below 32°F at Marengo, Winters 1901-1902 to 1995-1996 14 Figure 8. Annual Number of Days with Minimum Temperatures Equal to or Below O°F at Marengo, Winters 1901-1902 to 1995-1996 15 Figure 9. Annual Precipitation at Marengo, 1901-1996 16 Figure 10. Annual Number of Days with Measurable Precipitation at Marengo, 1901-1996 17 Figure 11. Annual Snowfall at Marengo, Winters 1901-1902 to 1995-1996 17 Figure 12. Annual Number of Days with Measurable Snowfall at Marengo, Winters 1901-1902 to 1995-1996 18 Figure 13. Annual Number of Days with Thunderstorms at Chicago, 1959-1995 19
xii Streamflow Figure 14. Stream Gaging Stations in the Kishwaukee River Basin 22 Figure 15. Average Annual Streamflow for the Gaging Stations in the Kishwaukee River Basin 23 Figure 16. Eleven-Year Moving Averages for Streamflow and Precipitation, 1900-1990 24 Figure 17. Flow Duration Curves (Discharge Versus Probability) 25 Figure 18. Monthly Flow Probabilities for the Kishwaukee River at Belvidere 26 . Figure 19. Annual Peak Discharges for Gaging Stations in the Kishwaukee River Basin 27 Figure 20. Seven-Day Low Flows for the Kishwaukee River and Tributaries 29
Erosion and Sedimentation Figure 21. Sediment Monitoring Stations in the Kishwaukee River Basin 34 Figure 22. Variability of Instantaneous Suspended Sediment Concentrations for the Kishwaukee River at Belvidere : 35 Figure 23. Variability of Instantaneous Suspended Sediment Concentrations for the Kishwaukee River near Perryville, (a) USGS Data and (b) ISWS Data..... 36 Figure 24. Variability of Instantaneous Suspended Sediment Concentrations for the South Branch Kishwaukee River at De Kalb 37 Figure 25. Variability of Instantaneous Suspended Sediment Concentrations for the South Branch Kishwaukee River near Fairdale 37 Figure 26. Instantaneous Suspended Sediment Load for the Kishwaukee River at Belvidere (a) Water Year 1981 and (b) Water Year 1982 39 Figure 27. Instantaneous Suspended Sediment Load for the Kishwaukee River near Perryville with data collected by the USGS for (a) Water Year 1979 - (c) Water Year 1981... ; 41 Figure 28. Instantaneous Suspended Sediment Load for the Kishwaukee River near Perryville with data collected by the ISWS for (a) Water Year 1983 - (h) Water Year 1990 44 Figure 29. Instantaneous Suspended Sediment Load for the South Branch Kishwaukee River at De Kalb (a) Water Year 1980 and (b) Water Year 1981 52 Figure 30. Instantaneous Suspended Sediment Load for the South Branch Kishwaukee River near Fairdale (a) Water Year 1981 and (b) Water Year 1982 54
xiii List of Tables
Introduction Table I. Major Tributaries of the Kishwaukee River Basin I Table 2. Significant Lakes and Reservoirs in the Kishwaukee River Basin : 3 Table 3. Wetlands in the Kishwaukee River Basin 4 Table 4. Distribution of Land Slopes for McHenry, De Kalb, and Boone Counties .. 9 Table 5. Acreages of Selected Crops in the Kishwaukee River Basin Based on lAS Data 10
ClinmreandT~nminClinmu Table 6. Temperature Summary for Marengo 12 Table 7. Average Annual Temperature during Consecutive 30-Year Periods 13 Table 8. Precipitation Summary for Marengo 15
St~mflow Table 9. USGS Stream Gaging Stations with Continuous Discharge Records 2I Table 10. Trend Correlations for Annual and Seasonal Flows 25 Table 11. Trend Correlations for Flood Volume and Peak Flow 28 Table 12. Monthly Distribution of Top 25 Flood Events 28 Table 13. Trend Correlations for 7-Day Low Flows 30 Table 14. Low Flows and Drought Flows Experienced during Major Droughts 30
Erosion and Sedimentation Table 15. Sediment Monitoring Station"s in the Kishwaukee River Basin 33 Table 16. Annual Sediment Load for the South Branch Kishwaukee River at De Kalb and the Kishwaukee River near Perryville 38
Water Use and Availability " " Table 17. Reported Private Wells in the Kishwaukee River Basin 59 Table 18. Ground-Water Use Trends in the Kishwaukee River Basin : 61 Table 19. Surface Water Use Trends in the Kishwaukee River Basin 61
Ground-Water Quality Table 20. Chemical Constituents Selected for Trend Analysis, Unconsolidated Systems 67 Table 21. Chemical Constituents Selected for Trend Analysis, Bedrock Aquifer Systems 68
xiv Introduction
I The Kishwaukee River is located in northern llIinois bordering the state of Wisconsin. Figure I shows the Kishwaukee River basin and its major streams. The basfn has a total I area of approximately 1,250 square miles (sq. mi.), including about 32 sq. mi. in Wisconsin, and with drainage in 6 llIinois counties: Boone, De Kalb, Kane, McHenry, Ogle, and Winnebago. The Kishwaukee River originates near Woodstock, in McHenry County, and flows west for 64 miles until its confluence with the Rock River in Winnebago County.
Mean annual precipitation for the area is 36.2 inches, and the corresponding average annual streamflow is 9.3 inches.
Rivers and Streams
There are more than 1,300 miles of rivers and streams in the Kishwaukee River basin, as measured from I: 100,000 topographic mapping. Larger streams (those with watersheds greater than 10 square miles) account for about 42% of this total, or approximately 550 river miles. By far, the largest tributary to the Kishwaukee River is the South Branch Kishwaukee River, with a drainage area of 441 sq. mi. Other major streams are listed in Table I, and their locations are shown in Figure I. The headwaters of most of the major streams originate on the eastern fringe of the watershed, and flow west to converge with the Kishwaukee River. Most of the headwater streams to the east have artificial drainage, but farther downstream most of the streams are well-developed and have not required channelization (Mattingly and Herricks, 1991).
Table 1. Major Tributaries of the Kishwaukee River Basin
Drainage Area Total miles of Stream Name Counties mil lar r streams Killbuck Creek Ogle 139 42 South Branch Kishwaukee River De Kalb 441 185 East Branch of the South Branch De Kalb, Kane 122 58 Beaver Creek Boone 70 31 Piscasaw Creek Boone, McHenry 128 77 Coon Creek Boone, McHenry 156 72 South Branch Kishwaukee River (East) McHenry 74 37 North Branch Kishwaukee River McHenry 40 19
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N Basin Boundary • Lskes Major Rivers and N Streams
Figure t Rivers, Streams, and Lakes in the Kishwaukee River Basin Lakes
Though the Kishwaukee River basin has numerous small lakes and ponds, both man made and naturally-occurring, it has relatively few sizeable lakes. Two lakes, listed in Table 2, have surface areas greater than 40 acres. Candlewick Lake, which is located 6 miles north of Belvidere in Boone County and impounds a tributary to Beaver Creek, was built in 1972. The lake vicinity is used primarily for residential development. Bard Lake is a natural, glacially-formed lake on the eastern edge of the basin near the city of Crystal Lake, and is the site of a golf course.
Table 2. Significant Lakes and Reservoirs in the Kishwaukee River Basin
Surface Name Count area (acres) Pri use Candlewick Lake Boone 200 Recreation Bard Lake McHenry 44 Recreation
Wetlands
Wetlands are an important part of our landscape because they provide critical habitat for many plants and animals and serve an important role in mitigating the effects of storm flow in streams. They are also government-regulated landscape features under Section 404 of the Clean Water Act. In general, wetlands are a transition zone between dry uplands and open water; however, open-water areas in many upland depressional wetlands are dry at the surface for significant portions of the year.
The Kishwaukee River basin has about 2.6% (19,907 acres) of its total area in wetlands (Table 3). For wetland categories. see the table describing wetland and deepwater habitat in Volume 3: Living Resources.
The hydrogeology of wetlands allows water to accumulate in them longer than in the surrounding landscape, with far-reaching consequences for the natural environment. Wetland sites become the locus of organisms that require or can tolerate moisture for extended periods of time, and the wetland itself becomes the breeding habitat and nursery for many organisms that require water for early development. Plants that can tolerate moist conditions (hydrophYtes) can exist in these areas, whereas upland plants cannot successfully compete for existence. Given the above conditions, the remaining wetlands in our landscape are refuges for many plants and animals that were once widespread but are now restricted to existing wetland areas.
The configuration of wetlands enables them to retain excess rainwater, extending the time the water spends on the upland area. The effect of this retention on the basin is to delay the delivery of water to the main stream. This decreases the peak discharges of storm flow or floods, thus reducing flood damages and the resulting costs. It is important to realize that the destruction of wetland areas has the opposite effect, increasing peak flood flows and thereby increasing flood damages and costs.
3
---.__._ Table 3. Wetlands in the Kishwaukee River Basin
Subbasin Wetlands %of %of % of total Subbasin name Acres area Acres subbasin wetlands BeaverCr. '44,748 5.7 1,047.77 2.3 5.3 Burlington Cr. 15,239 2.0 122.41 0.8 0.6 Coon Cr. 74,867 9.6 1,513.95 2.0 7.6 E. Br. Killbuck Cr. 29,265 3.8 214.76 0.7 I.l E. Br. Kishwaukee R. 78,266 10.0 856.05 I.l 4.3 Hampshire Cr. 8,419 I.l 135.50 1.6 0.7 Killbuck Cr. 59,056 7.6 88D.43 1.5 4.4 Kishwaukee R. (lower central) 17,033 2.2 338.64 2.0 1.7 Kishwaukee R. (lower) 14,362 1.8 508.12 3.5 2.6 Kishwaukee R. (upper central) 17,432 2.2 374.81 2.2 1.9 Kishwaukee R. (upper) 63,910 8.2 4,225.05 6.6 21.2 L. Beaver Cr. 8,303 I.l 254.75 3.1 1.3 Lawrence Cr. 11,714 1.5 373.93 3.2 1.9 MokelerCr. 5,869 0.8 266.38 4.5 1.3 N. Br. Kishwaukee R. 24,971 3.2 1,107.50 4.4 5.6 Owens Cr. 28,658 3.7 232.90 0.8 1.2 Piscasaw Cr. 37,998 4.9 1,099.42 2.9 5.5 Rosetter Cr. 6,076 0.8 24.61 0.4 0.1 Rush Cr. 19,804 2.5 473.86 2.4 2.4 S. Br. E. Kishwaukee R. 46,996 6.0 3,287.88 7.0 16.5 .S. Br. Kishwaukee R. (lower) 104,196 13.4 2,194.80 2.1 11.0 S. Br. Kishwaukee R. (u er) 62,554 8.0 373.25 0.6 1.9 Totals 779,736 100.0 19,906.77 2.6 100.0
The location of wetlands affectS many day-to-day decisions because wetlands are considered "Waters of the United States" (Clean Water Act) and are protected by various legislation at the local, state, and federal levels (for example, the Rivers and Harbors Act of 1899, Section 10; the Clean Water Act; and the Dlinois Interagency Wetlands Act of 1989). Activities by government, private enterprise, and individual citizens are subject to regulations administered by the U.S. Army Corps of Engineers. Under a Memorandum of Agreement between federal regulatory agencies with jurisdiction over wetlands, the Natural Resources Conservation Service takes the lead in regulating wetland issues for agricultural land, and the U.S. Army Corps of Engineers takes the lead for all nonagricultural lands.
In contexts where wetland resources are an issue, the location and acreage of a wetland will be information required by any regulatory agency, whether local, state, or federal. Currently, there are two general sources of wetland location information for lllinois: the National Wetland Inventory (NWI), completed in 1980, and Illinois Land Cover, an Atlas (ILCA) by the Dlinois Department of Natural Resources (1996). The State of lllinois used
4 the NWI infonnation to publish the Wetland Resources ofIllinois: An Analysis and Atlas (Suloway and Hubbell, 1994). While this atlas is not of suitable scale for landowners or government agencies to use for individual wetland locations, it can be used by agencies or groups that consider wetlands in an administrative or general government manner and focus on acreage and not individual wetland boundaries.
The NWI program involved identifying wetlands on aerial photographs of I:58,000 scale and publishing maps of this information using USGS I:24,000-scale topographic quadrangle maps as the base. NWI quadrangle maps for the Kishwaukee R,iver basin are shown in Figure 2. Individual quadrangles can be purchased from:
Center for Governmental Studies Wetland Map Sales Northern lllinois University De Kalb, ll.- 60115 Telephone: (815) 753-1901
Digital data by quadrangle are available from the NWI Web site: www.nwi.fws.gov.
The ll.-CA inventory used Landsat Thematic Mapper satellite data as the primary source for interpretation. National Aerial Photography Program photographs verified the land cover classification and helped ensure consistency from area to area within lllinois. The ll.-CA and companion compact disc can be purchased from:
lllinois Department of Natural Resources 524 South Second Street Lincoln Tower Plaza Springfield, IL 62701-1787 Telephone: (217) 524-0500 E-mail: [email protected] Web site: http://dnr.state.il.uslctap/ctaphome.htm
Although the ILeA and NWI programs were not meant for regulatory purposes, they are the only state or regional wetland map resources available and are the logical sources for beginning a wetland assessment. The presence or absence of wetlands as represented by the wetland maps is not certified by either the ll.-CA or the NWI mapping program. Figure 3, taken from the Cherry Valley Quadrangle in the Kishwaukee River basin, exemplifies the infonnation that can be expected from NWI maps.
. In some areas with intense economic development and significant wetland acreage, the NWI maps have been redone or updated for use in designating or locating wetland areas. Whatever the source of wetland map information, the user should be aware that this information is a general indication of wetland locations, and the boundaries and exact locations should be field-verified by persons trained or certified in wetland delineation.
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Figure 2, Wetlands from the National Wetlands Inventory and quadrangle map boundaries for the Kishwaukee River assessment area. The inset area is depicted in the following figure 15
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22
27
Wetlands Roads .~ Deepwater habitat Sections I N SOlI. 1:24000 i
Kishwaukee River AA Figure 3. National Wetlands Inventory information from the Cherry Valley 7.5-minute quadrangle maps showing wetlands, deepwater habitats, and NWI codes Given the limitations of most existing wetland maps, more complete information can be obtained by comparing mapped wetlands with other regional attributes such as shallow aquifers, subsurface geology, and placement in the landscape. When these comparisons show consistent regional patterns (for example, placement in the landscape or correlation with a particular geologic material), any parcels of land with similar landscape positions or geologic materials can be considered potential wetland sites even if maps do not show them as wet.
Physiography
The Kishwaukee River basin is an area of gently rolling topography, interspersed with broad alluvial valleys and outwash plains. The land elevations in the watershed range from a low of 680 feet where the Kishwaukee River joins the Rock River near Rockford, to over 1180 feet in the northeast edge of the watershed near the lllinois-Wisconsin border. Except for the eastern fringe of the watershed, along the Marengo Ridge in McHenry County, the elevations of the upland areas in the watershed are generally less than 900 feet.
. Leighton et al. (1948) defined three physiographic regions located in the Kishwaukee River basin: the Wheaton Morainal Country, the Bloomington Ridged Plain, and the Rock River Hill Country. The eastern fringe of the watershed falls within the Wheaton Morainal Country. This area has a complex topography created from glacial deposition, including rolling hills, broad morainic ridges, scattered depressions with wetland areas, and oversized valleys formed by glacial outwash. The primary glacial deposit is till, which forms the hills and ridges and is normally composed of relatively impermeable silts and clays. Extensive sand and gravel outwash deposits, which are highly permeable, can be found in stream valleys.
The southern portion of the watershed, identified as that portion drained by South Branch Kishwaukee River, is primarily located in the Bloomington Ridged Plain. This region is characterized by depositional plains of till, with nearly flat to gently rolling topography crossed by low and broad end moraines. Stream erosion has only slightly modified the landscape, and the headwater streams are generally poorly-incised with some requiring channelization.
The western half of the watershed falls in the Rock River Hill country. The glacial deposition here is older and thinner than the previous two regions. The resulting topography more closely reflects the underlying pre-glacial (bedrock) surface, and is characterized by subdued rolling hills and more fully developed stream valleys. The variability of topography in the basin is illustrated by the distribution of land slopes, as shown in Table 4. The land slopes for McHenry, De Kalb, and Boone counties are representative of the three topographic regions, the Wheaton Morainal Country, Bloomington Ridged Plain, and Rock River Hill Country, respectively. In general, the land slopes are steepest in the eastern portion of the basin, in McHenry County, and flattest in the southern portion of the basin, in De Kalb County.
8 Table 4. Distribution of Land Slopes for McHenry, De Kalb, and Boone Counties
Sio e De Kalb Count Boone Count 0- 2 % 52.9 42.1 2 - 4 38.9 43.5 4 - 7 7.2 12.4 7 -12 0.8 1.8 12 -18 0.1 0.1 18 -30 0.1 0.0 > 30 0.0 0.0 0.2 Source: Runge et al. (1969)
Land Use
Agriculture is a major land use in the seven major counties (Boone, De Kalb, Kane, Lee, McHenry, Igle, and Winnebago) in the Kishwaukee River basin. lllinois Agricultural Statistics (lAS) data indicate that in 1995 agriculture acreage accounted for approximately 64% of the total watershed area. Total crop acreage has remained steady over time, averaging approximately 505,000 acres. Figure 4 shows changes in selected crop acreage in the basin from 1925 to 1995.
In 1925 the dominant crops were grassy crops (wheat, oats, and hay) and com, accounting for 92% of the agricultural crops grown in the basin (226,000 acres for com and 232,000 acres for grassy crops). However, in the 1950s soybean acreage sharply increased while grassy crop acreage decreased; this inverse relationship continued through 1995. Soybean acreage exceeded grassy crop acreage in 1970. Acreage for both crops leveled out in the 1980s and has remained relatively steady through 1995 at approximately 180,000 acres for soybeans and 31,000 acres for grassy crops. Corn acreage has remained fairly steady, averaging 270,000 acres and only slightly increasing over time. The highest corn acreage ·was in 1985 (352,000) and lowest in 1940 (205,000). The sharpest drop of corn acreage (122,000) was in 1983. The 1995 corn acreage for the Kishwaukee River basin was approximately 283,000 acres.
9 ---Corn 600,000 "....,...... rl Soybeans i ! !
.••.••••• Corn & Soybeans \ f----I - . - .. Wheat/Oats/Hay 1-+---+---+,--+----1 500,000 ~~.. ~. : .., ...... ~~. \:- .' . I'! " i". • • I .. '" . 400,000 ...... ! ,:of -. .. CJ) ~ W ." : . rJil(\ ...J.•.: 1\ a:: 300,000 ~ 200,000 \ ,. t ~ \ I~! ! ! ! !....., ! '-. 1 i j 100,000
0 1920 1930 1940 1950 1960 1970 1980 1990 2000
Figure 4. Acreages ofSelected Crops in the Kishwaukee River Basin Based on lAS Data
10 Climate and Trends in Climate
This chapter reviews climate trends in and around the Kishwaukee River basin since the tum of the century. Climate parameters examined include annual average temperature, the number of days with highs above or equal to 90°F, the number of days with lows below or equal to 32°F, the number of days with lows below or equal to OaF, annual precipitation, the number of days with measurable precipitation, annual snowfall, and the number of days with measurable snowfall. Extreme weather events examined in this report are tornadoes, hail, and thunderstorms.
The Kishwaukee River basin in north-central lllinois occupies portions of Boone, McHenry, Kane, De Kalb, Winnebl!-go, and Ogle Counties. The climate of this area is typically continental, as shown by its changeable weather and the wide range of temperature extremes. Summer maximum temperatures are generally in the 80s, with lows in the 50s or 60s, while daily high temperatures in winter are generally in the 20s or 30s, with lows in the teens or 20s. Based on the latest 30-year average (1961-1990), the average first occurrence of 32°F in the fall is October 4, and the average last occurrence of 32°F in the spring is May 7.
Precipitation is normally heaviest during the growing season and lightest in midwinter. Thunderstorms and associated heavy showers are the major source of growing season precipitation, and they can produce gusty winds, hail, and tornadoes. The months with the most snowfall are November, December, January, February, and March. However, snowfalls have occurred as early as September and as late as May. Heavy snowfalls rarely exceed 12 inches.
The climate data used in the following discussions originate at Marengo, lllinois (McHenry County), the National Weather Service.(NWS) Coop site with the longest record (1901-1996), located within the north-central portion of the basin. Supportive data and analyses for nearby lllinois sites can be found in reports by the lllinois Department of. Energy and Natural Resources (1994) and Changnon (1984).
Temperature
The average January maximum temperature is 27°F and the minimum is 8°F, whereas the average July maximum and minimum temperatures are 85°F and 60°F, respectively (Table 6). The average annual temperature at Marengo is 46.9°F. The warmest year of record was 1921, with an average of 51.7°F, while the coldest was 1917, with an average of 44.5°F.
11 Table 6. Temperature Summary for Marengo (Averages are from 1961-1990 and extremes are from 1901-1996, Temperatures are in OF,)
# of days # of days # of days Avg. Avg. Record Record with high with low with low Month high low high (year) low (year) >90°F <32°F Although there is a great deal of year-to-year variability, average annual temperatures at· Marengo show a warming trend from 1901 to 1949. followed by a cooling trend through 1996 (Figure 5). 52 -r--.,--"---:--"""'-"""'-"""'-"""'-"""'-"""'-"" 51 -- --' -- -- .. - , -- ..' .. -'-- -- .' ....'- -- , -- --' -- - u:~ , , , , ' ~ 50 --, N" . .. -.., ... -- ...-- - ::::l . . , . , ' ai , ' .- _. . , Qj 49 , . .., a. E ~ 48 iii E47 . ., ., ~ , , ' . , , ' . 5i 46 . " . " . ~ - . - '. - . .. -- . " . . . ',' -- .- . . . Q) ~ ...... -_' , , _--_. , , --_ . . 45 . . . , ,, , . 44 +--+--+--+---+---+---+---+---+---+---1 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Figure 5. Average Annual Temperature/or Marengo. 1901·1996 12 Examination of average temperatures over time is one way to clarify trends. The NWS has adopted 30-year averages, ending at the beginning of the latest new decade, to represent climate "normals." These averages were adopted to filter out some of the smaller scale features and yet retain the character of the longer term trends. Consecutive, overlapping "normals" for the last five 30-year periods at Marengo are presented in Table 7. The consecutive averages demonstrate a warming trend through the 1931-1960 period, followed by a cooling trend through the 1961-1990 period. Table 7. Average Annual Temperature during Consecutive 30-Year Periods Averaging Average tempera period ture (oF) 1901-1930 47.5 1911-1940 48.0 1921-1950 48.4 1931-1960 48.6 1941-1970 48.2 1951-1980 . 47.9 1961-1990 47.7 The frequency of extreme events sometimes conveys a clearer picture of trends than average values. The annual 'number of days with temperatures equal to or above 90°F is shown in Figure 6. Not too surprisingly, the time series bears little resemblance to that of annual temperature (Figure 5), because the number of days with temperatures above 90°F represents only the high summer temperature extremes. Figure 6 shows an increase through 1940, followed by a slow decline through 1980, before returning to somewhat higher values from 1981 to 1996. 60 .....-,.....-...,...-....,..-.....,.--,....--.,.....-..,....-,.....-...,...--, ..'. . -- '. -- . ; --- .' '. - .. .' - . . .'. --- ~ . u.. 50 , , , , . . , .. o 0> II ... , . - .., ..... -- . , ...... /I 40 ,- , - , , or: .2' J: ....' - .. == 30 .~ ~ cg 20 . '.. - . '0 ~ 10 . . '... . - - ..' .. - .... 0+J--;-JL.....t--+---+---+---+---t--+--l---I 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Figure 6. Annual Number ofDays with Maximum Temperatures Equal to or Above 90°F at Marengo. 1901-1996 13 Figure 7 shows the winter frequency of daily minimum temperatures equal to or below 32°F. The frequency of such temperatures shows an increase through 1995-1996, except for the winters of 1983-1984 and 1984-1985. Figure 8 shows the number of days per year when the minimum temperature was equal to or below O°F, beginning with the 1901-1902 winter. No long-term trends are evident. However, there is a large degree of variability from year to year. The period from the mid-1970s to the mid-1980s showed generally higher frequencies than any other time. Precipitation Average annual precipitation at Marengo is 36.19 inches, with more rainfall in the spring .and summer than in fall and winter (Table 8). Late spring, summer, and early fall precipitation is primarily convective in nature, often associated with short thunderstorms (1-2 hours in duration). During the remainder of the year, the precipitation is longer and associated with synoptic-scale weather systems (cold fronts, occluded fronts, and low pressure systems). The wettest year of record was 1972 (51.70 inches). The driest was 1901 (19.70 inches). 180 .,--.,....-.,....-.,....-..,--..,--..,--..,--..,--..,----, ...... , , , --_ , , ,_-.---_ , , - 170 , . , . , . . , LL ~ , , e160 ...... - . . 3: .9 ~: E 150 3: ~ - , .' - •• '. • • _! •••' - - •• '. ~ 140 .. ' '0 # 130 • __' _ • • • • • .. __ • J •••• ' ••• _ '. • • • ~ •• ••' • •• _ ' •• - - 120 -1--+--+--+--+--+--+--+--+--+---1 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Figure 7. Annual Number ofDays with Minimum Temperatures Equal to or Below 32"F at Marengo. Winters 1901-1902 to 1995-1996 14 50 -,--..,.--..,.--..,...-..,...-...,....--,...-...,...-...,...-";""--, , , - . - -' - . . . '. -- . ~ -- . .' -- . - '. - . . .' . -- -'. - . - . -- .. - .. u. 40 , , , ' ,, , , o C ~ 30 ...J :5 .~ 0-4--+--...... -+--+---I---+---+---+--+---4 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Figure 8. Annual Number ofDays with Minimum Temperatures Equal to or Below OOF at Marengo. Winters 1901-1902 to 1995-1996 Table 8. Precipitation Summary for Marengo (Averages are from 1961-1990 and extremes are from 1901-1996. Precipitation is in inches.) Largest one #of Avg. Record Record day amount Snow days wi Month precip. high (year) low (year) (year) fall precip. January 1.51 4.51 (1965) 0.10 (1981) 2.96 (1938) 9.7 7 February 1.11 2.84 (1944) 0.00 (1969) 1.26 (1926) 7.1 6 March 2.37 6.36 (1976) 0.24 (1910) 2.10 (1948) 6.3 8 April 3.64 7.88 (1993) 0.26 (1901) 2.97 (1909) 1.7 10 May 3.50 9.89 (1996) 0.42 (1934) 3.33 (1905) 0.2 8 June 4.39 10040 (1993) 0.19 (1922) 3.50 (1967) o 9 July 3.99 8.34 (1978) 0.38 (1946) 4.07 (1978) o 8 August 4.32· 11.70 (1987) 0.63 (1970) 3,03 (1996) o 8 September 3.94 10.92 (1972) 0.00 (1979) 3.34 (1986) o 8 October 2.67 7.63 (1941) 0.00 (1952) 3.20 (1954) 0.2 7 November 2.67 6.25 (1985) 0.15 (1904) 2.87 (1935) 2.1 8 December 2.08 5.17 (1971) 0.33 (1930) 2.32 (1909) 8.4 8 The annual precipitation at Marengo is shown in Figure 9. There are no trends from 1901 to 1960, followed by noticeably higher values through 1996. The precipitation values during this later period were about 4 inches higher on average than values from 1901 to 1960. 15 55 ,.--,...... ---,-.....,.-.....,..-.....,...,...... ,....-..,.--.,--,...... -, 50 .., .... ,.... , ....,.... ,....., .... ,.... , ...., .... 45 · . - -. - - - . , . . - . ..., .. ~ ... ~ . -- .. . - .. - -,. - . . ~c: ~: =g 40 ... :..: .. ... ~ ,.~MI :§-35 .,~ . : .... I ...... , ~ , ' a.. ~\' 30 · . .. tJ . ~·AI' ~ 25 ·.- _." "... !1.. .. -- . -.' .... - .. " - . - 20 ~-+-----l--+--+--+---+--+--..--I----1 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Figure 9. Annual Precipitation at Marengo. 1901-1996 The number of days per year with measurable precipitation (i.e., more than a trace) is shown in Figure 10. No clear trends are evident. Although there are several instances (1938, 1957, and 1980) when the number of days per year changes dramatically, this is likely due to changes in exposure, location, or observer. The annual precipitation (Figure 9) shows no such pattern, suggesting that the changes shown in Figure 10 mainly affect lighter precipitation events. Precipitation at Marengo is more frequent during summer months than during winter months. Average winter snowfall at Marengo is 34.1 inches, with great year-to-year variability. . The most winter snowfall was 81.4 inches during 1978-1979, whereas the least was only 4.4 inches during 1933-1934. Snowfall from the 1901-1902 winter season through the 1995-1996 season is shown in Figure 11. The period from 1940-1941 through 1995-1996 shows higher snowfall totals than the previous period. Figure 11 shows the number of days with snowfall each winter, from 1901-1902 through 1995-1996. The number of days with snow shows the same pattern as that for the number of days with precipitation, with shifts occurring in 1938, the mid-1950s, and the late 1970s. A snowfall of more than 6 inches occurs about once a year. Snow cover is frequently experienced at Marengo, typically lasting from a few days at a time to up to three months. ' 16 140 -r--~-~-"""--"----"-",,,--,,,,,,-"""r-"""--, <: ,g 120 ~ a. '0 ~ a. .c 100 ""~ ~ Q 15 80 ... -_ .. ~ 60 -I--+--+--+--+--+-~+--+--+--+-~ 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Figure 10. Annual Number ofDays with Measurable Precipitation at Marengo. 1901-1996 100 T"""--"--"""-"""-"""-"""-"""-"""-"""-"""---' - . . .· ...... , -- ..... --, ..... --- ,. . -- , . .. _. - ... - 80 · , , . , . , ~ , ., ., - . - .· . -- ... - - ... - . - ...... - - . . .. _ ... --- :§. 60 , , i en<: 40 20 . ..' -- . ' . .. 0~-+----+--+--t---+--+--+----+--+---1 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Figure 11. Annual Snowfall at Marengo, Winters 1901-1902 to 1995-1996 17 35 .,....-..,...-..,...-..,...-..,...-...,...-...,..-....,....-....,....-...,....--, 30 ..• ~ •••••.•••.•• ~ I: ••••••••••• J{... _j. : .•u :.~,( ...:. . ..:.. _.: ... . -- .... ~ . :~ .:. _. :--\: ~.: ~ ....: ·11 " " ., ., --- ...., --, . ',' . . . " _., , . . ~ - - . " , , , , , , 5 ...., .... ,.... ,. ..,.... , ... , ....,....•...., .... o-l--+----I~--+--+-_+-_+_--+--.;--+--___! 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Figure 12. Annual Number ofDays with Measurable Snowfall at Marengo, Winters 1901-1902 to 1995-1996 Precipitation Deficits and Excesses Following are the driest years in the basin in tenns of annual precipitation shortfall, starting with the driest: 1901, 1910, 1939, 1946, 1958, 1917,1922, 1962, 1934, and' 1988. Driest summer seasons (June through August) in the basin include: 1918, 1946, 1991, 1910, 1948, 1901, 1927, 1988, 1922, and 1930. SigniJ'jcantly above average precipitation fell at Marengo 1972, 1973, 1990, 1993, 1965, 1967, 1926, 1921, 1978, and 1959. No single decade dominated in tenns of years with excessive precipitation. Severe Weather Tornadoes Although tornadoes are not uncommon in lllinois, most people do not expect to be affected directly, even if they live in the state for a lifetime. This is because tornadoes are generally only one-quarter mile in diameter, travel at roughly 30 miles per hour for only 15-20 minutes, and then dissipate, directly affecting a total area less than 2 square miles. Since lllinois observes an average of 28 tornadoes a year (though the actual number varies from fewer than ten to about 100 during the last 35 years), the total area directly affected by tornadoes annually is only about 55 square miles, 0.1 % the total area of the state. Even with 96 tornadoes reported in lllinois in 1974 (the greatest number reported in the last 30 years), the affected area was only about 0.3% the total area of the state. These numbers do not diminish the effect on those experiencing property damage, injury, or worse, but they demonstrate the extremely low probability of direct impact at any given location. 18 Regular reporting of tornadoes in lllinois began in 1959. From that time through May 1995, 20 tornadoes were recorded in the Kishwaukee River basin with no apparent trends in frequency or intensity. On average, the basin experiences about one tornado every two years. The maximum number of tornadoes reported per year is three (1959, 1967, and 1991), with 26 of the last36 years experiencing no tornado activity. Hail Hail events are somewhat rare and typically affect a very small area (from a single farm field up to a few square miles). Unfortunately, very few NWS Coop sites 'measure hail. The combination of small, infrequent events being measured by a sparse climate network makes for very few reliable, long-term records of these events, particularly for large areas. Based on Changnon (1995), the Kishwaukee River basin experiences two hail days per year, with the actual number varying greatly from year to year. The year with the most hail days was 1947, which had ten. There are no indications of trends in hail days from 1901 to 1994, based on the nearest records from Chicago. Thunderstorms On average, the Kishwaukee River basin experiences about 26 days with thunderstorms each year. The annual number of days with thunder over the basin since 1959 is shown in Figure 13, which is composed of data from Chicago (1959-1995). There is substantial year-to-year variation in thunderstorm days, ranging from as many as 44 in 1974 to as few as 13 in 1966.' There is no significant trend in thunderstorm days. 50 -r----..,....---..,....,.....--..,...---..,....-----, 10 .J----+-----1---...... ----+---~ 1950 1960 1970 1980 1990 2000 Figure 13. Annual Number ofDays with Thwuierstorms at Chicago, 1959-1995 19 Summary The average annual temperature for Marengo shows a warming trend through 1949, followed by a cooling trend through 1996. The number of days with temperatures above or equal to 90°F shows an increase through 1940, followed by a slow decline through 1980, before returning to somewhat higher values from 1981 to 1996. The number of days with temperatures below or equal to 32°F shows an increase through 1996. The number of days with temperatures below or equal to OaF shows no trends. For precipitation, there are no trends in total annual precipitation from 190I to 1960; however, the period 1961-1996 experienced about 4 more inches per year than the period 1901-1960. There are no trends in the number of days with measurable precipitation. For snowfall, there is no long-term trend in the seasonal totals; however, the period from 1940-1996 showed higher snowfall amounts than earlier periods. No trends are evident in the number of days with snow. Records extending back to 1901 show no clear trends in hail events. Similarly, there are no apparent trends in tornado events, although records date only to 1959. The number of days with thunderstorms has been recorded since 1959 with no significant trends. 20 ------~~ -~-- Streamflow Surface water resources are an essential component of any ecosystem because they provide different types of habitats for aquatic and terrestrial biota. In addition to their natural functions, they are sources of water supply for domestic, industrial, and agricultural use. Changes in natural and human factors, such as climate, land and water use, and hydrologic modifications, can greatly affect the quantity, quality, and distribution (both in space and time) of surface waters in a river basin. There are at least 1,100 miles of rivers and streams in the Kishwaukee River basin. The status of these rivers and streams is monitored by stream gaging stations, which measure the flow of water over time, providing information on the amount and distribution of surface water passing the station. Since it is not feasible to monitor all streams in a basin, gaging stations are established at selected locations, and data collected are transferred to other parts of the basin by applying hydrologic principles. Streamflow records are used to evaluate the impacts of changes in climate, land use, and other factors on the water . resources of a river basin. Stream Gaging Records Six U.S. Geological Survey (USGS) gaging stations in the llIinois portion of the Kishwaukee River basin have five or more years of continuous daily flow data. These stations are listed in Table 9, and their locations are shown in Figure 9. Table 9. USGS Stream Gaging Stations with Continuous Discharge Records Drainage Record length Period 2 USGSID Station name area (mi ) (years) of record 05438250 Coon Creek at Riley 85.1 21 1961-1982 05438500 Kishwaukee River ,at Belvidere 538.0 57 1939-1996 05439000 South Branch Kishwaukee River 686.0 25 1925-1933, at De Kalb 1979-1996 05439500 South Branch Kishwaukee River 387.0 57 1939-1996 near Fairdale 05440000 Kishwaukee River near Perryville 1099.0 57 1939-1996 05440500 Killbuck Creek near Monroe Center 117.0 32 1939-1971 Human Impacts on Streamflows in the Basin The characteristics of streamflow in any moderately developed watershed will vary over time because of the cumulative effect of human activities in the region. Certain modifications to the watershed, such as point withdrawals and discharges to the streams, 21 '~!!,!,,!!!,!,,!~";;;;;==;;;;'~'~!!,!,,!~~'!!;'===~4'O.1 I .lIle'.r. N Basin Boundary • Gaging Station Major Rivers and N Streams Figure 14. Stream Gaging Stations in the Kishwaukee River Basin may have readily definable impacts on the stream flows. Impacts from other changes, such as changes in agricultural practices, drainage, and removal of wetland areas, can be inferred but are difficult to quantify, primarily because most of these began before stream gaging activities and thus cannot be evaluated using the available flow records. Of the human modifications in the basin, water use has the only direct, observable impact on flows in the Kishwaukee River. For a few selected streams during low flow situations, the overall impact of water use is to add flow through the discharge of treated wastewater. Most of the streams in the watershed have a high degree of sustained low flows, and in these cases the discharges represent a relatively small contribution to the total low flow. The South Branch Kishwaukee River is the primary exception because it has the lowest natural low flow of the major streams in the watershed and also receives the largest discharge (treated wastewater from the city of De Kalb). Annual Streamflow Variability Average streamflow varies greatly from year to year, and can also show sizable variation between decades. Figure 15 shows the annual series of average streamflow for the stream gage records in the Kishwaukee River basin. As seen in this figure, the average flow during any given year is similar for most stations. Over the 57 years of record, the annual flows have ranged from a low of about 2 inches in the drought years of 1940,1956,1963, 1964, and 1977, to a high of over 25 inches in 1993. 35 r--r:::=:;;==:==='==:'======;---~------, ~ Coon Creek at Riley ---K1shwaukee River at Belvidere 3. -0-S. Sr. KishwIIukee River at Dekalb ~s. Sr. Klshwaukee River near Fairdale ---Kishwaukee River near Penyville 5 •-1------_----_---_------1 '94. 1850 '060 1870 '080 ,.... Figure 15. Average Annual Streamflowfor Gaging Stations in the Kishwaukee River Basin 23 The long-tenn average flow in the basin is 9.3 inches per year. Prior to 1970 the average annual flow was 7.3 inches, but since then has averaged over II inches. This increase in streamflow corresponds to a coincident increase in average precipitation. Figure 16 shows the II-year moving average of streamflow for the Kishwaukee River at Belvidere and that of the coincident precipitation measured at Marengo. The moving average (MA) streamflow is the average flow for II consecutive years; for example, the II-year MA for 1968 is the average flow for the period 1963-1973. The precipitation MA ranged from a high of 39 inches in 1972-1982 to a low of 31 inches in 1939-1949. The streamflow MA ranged from 12.4 inches in 1983-1993 to 6.0 inches in 1954-1964. 40,..------...,. 15 Kishwaukee River at Belvidere 39 '4 ill -0-Prectpttation ii 38 ...... Streamflow Z Q 37 ~.. ~36 ... w ~ 35· ~ ",34 z '> ~ 33 a: ili ~ 32 7 1.I""""..,y- 31 6 3O.L-- ---+---_--+---..,.~>__-~-- ...... 15 1940 1950 1960 1970 1980 1990 Figure 16. Eleven-Year Moving Averages for Streamflow and Precipitation. 1900·1990 Statistical, Trend Analysis Table 10 shows trend coefficients estimated for the annual flow record for individual stations. All of the gaging stations show a significant increasing trend in average flows over the period of record. However. there have been no observed trends in streamflows since the early 70s, nor were there any observed trends in flow for the earlier period of record prior to 1970. As discussed above, both the increasing trend of annual flows over the entire record and the recent lack of such a trend are related to climatic factors. 24 Table 10. Trend Correlations for Annual and Seasonal Flows Kendall trend correlation Annual Fall Winter Spring Summer Full Streamflow Record Kishwaukee River at Belvidere 0.312 0.273 0.257 0.166 0.200 South Branch Kishwaukee River near'Fairdale 0.284 0.282 0.249 0.168 0.227 Kishwaukee River near Perryville 0.283 0.278 0.235 0.174 0.230 Streamflow Record before 1970 Kishwaukee River at Belvidere 0.057 -0.007 0.048 -0.039 0.062 South Branch Kishwaukee River near Fairdale 0.044 0.080 0.053 0.016 0.090 Kishwaukee River near Perryville 0.021 0.021 0.053 -0.044 0.034 Streamflow Record since 1970 Kishwaukee River at Belvidere -0.028 0.028 0.157 -0.052 -0.151 South Branch Kishwaukee River near Fairdale -0.034 0.009 0.305 -0.046 -0.046 Kishwaukee River near Perryville -0.015 0.009 0.175 -0.040 -0.095 Geographic Flow Variability Figure 17 plots the flow duration curves for the five gages in the Kishwaukee River basin. A flow duration curve provides an estimate of the frequency with which the given flows are exceeded. As the figure shows, the flows for all of the streams varies significantly and can range from one-tenth to ten times the stream's average flow. 100000 ---K1SHWAUKEE RlVER NEAR PERRYVILLE. Il -b-SOUTH B~CH KISHWAUKEE RIVER NR FAIRDALE Il 10000 ...... SOUTH B~CH KlSHWAUKEE RIVER AT DEKALB. IL ~ ~KISHWAUKEE RIVER AT BELVIDERE. IL '--- ...... COON CREe< AT RILEY, IL lODO --=:::::; f:,... h ~ ...., h ~ ~ h u ~ ~ ui" ~ ~ ...., C) ~ ~ ~ 100 ....., ..... '"'l'! t:: ...... , u '-.., ....., '- i5'" ...... ~ ...... , ...... 10 l:::, to--. '-.;~~ ~ ...... ~ 0.1 10 20 50 50 70 80 os •• . Figure 17. Flow Duration Curves (Discharge Versus Probability) 25 Variations in the general shapes of the flow duration curves often point to significant differences in the hydrology of each stream. The flow duration curves for the . Kishwaukee River at Belvidere and Coon Creek at Riley have shallower gradients, and thus have less variability in their flows. These streams drain the northeastern portion of the basin, where there is a higher percentage of coarse-grained soils and substrata. These soils allow a greater amount of precipitation to be stored as shallow groundwater, which often are hydraulically connected to the streams. This provides for a more consistent release of baseflow during dry periods. To contrast, the soils in the watershed of the South Branch Kishwaukee River are more fine-grained, resulting in greater runoff during major storms flows and less baseflow during dry periods. Seasonal Flow Variability As with all other locations in Illinois, streams in the Kishwaukee River basin display a well-defined seasonal cycle. Figure 18 shows the monthly flow probabilities for the Kishwaukee River at Belvidere. Flows are greatest during the spring months, March and April, while lower flows are more common in late summer and autumn. However, this figure also shows that the average flow in any month can vary considerably from the long-term median condition. The variation in flows for the South Branch Kishwaukee River in De Kalb County are similar to the Belvidere flows, except that the low flows and median flows (50 percent exceedence) on the South Branch Kishwaukee River can be significantly lower during the summer and fall periods. 1600 ,------, D. : '. 1400 '. '. '. o. o BeMdere 90% ~Belvidere SOOk '200 .. D··8eMdere 10% '. ..,'000u ~ D, u'BOO '0 ~ .•0 a: I- "'BOO .c-" • o. D" _•••• -C. 400 'D' .0--- _00- ----0 ,"'" ----0 ~--_-~'.; ----~----D--__ D----D----D--- o.l--~-_"_- ~_...... -~~-_--_-~-~ JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Figure 18. Monthly Flow Probabilities for the Kishwaukee River at Belvidere 26 Table 10 (page 25) presents the results of trend analysis for each season of the year. All of the longer gaging records show an increasing trend for all seasons, generally similar in magnitude to the observed increase in average annual flows. Over the past thirty years however, only the winter season shows a significant trend in flows. Flooding and High Flows Figure 19 shows the annual series of peak flood discharges for the Kishwaukee River and tributaries. There is little trend in peak discharges. The February 1994 flood produced the flood of record along all of the larger streams in the basin, but major floods of similar magnitude have occurred throughout the entire record dating back to the floods of 1943 and 1946. l00000r---~r======---. ~Coon Creek at Riley ...... KishwaukBe River al Belvidere ___ South Branch Kishwaukee River near Fairdale -+-Kishwaukee Rivet nur Perryville ooסס1 1000 100-1-----+_---_-----+-----...... -----+------1 1940 1950 1960 1970 1980 1990 2000 Figure 19. Annual Peak Dischargesfor Gaging Stations in the Kishwaukee River Basin Results of the statistical trend analysis of flood records are given in Table 11. The trend analysis indicates that long-term gaging records in the Kishwaukee River basin show no trends in peak discharges. However, there is a small increasing trend in flood volume, as represented by the 7-day high flows (the highest consecutive seven days of flow during the year), at the Belvidere and Fairdale gages. The trend analysis also indicates that there has been an overall decrease in flooding since 1970. This decreasing trend is influenced by the fact that the period 1971-1979 contained a number of large floods. There were no significant trends in flooding before 1970. 27 Table 11. Trend Correlations for Flood Volume and Peak Flow Period Kendall trend correlation Station of record Flood volume Peak flow Kishwaukee River at Belvidere 1939-1995 0.157 0.045 1939-1969 -0.044 -0.147 1970-1995 -0.151 -0.193 South Branch Kishwaukee River near Fairdale 1939-1995 0.183 0.061 1939-1969 0.094 -0.099 1970-1995 -0.071 -0.145 Kishwaukee River near Perryville 1939-1995 0.113 0.Q18 1939-1969 0.016 -0.094 1970-1995 -0.200 -0.241 Table 12 presents the monthly distribution of the top 25 flood events for five stations. This table shows that major flooding occurs predominantly in February and March. This flooding is generally caused by snowmelt or a combination of snowmelt and heavy rainfall. Flooding on smaller rivers, such as Coon Creek and the South Branch Kishwaukee River near De Kalb is also common through the summer months. Table 12. Monthly Distribution of Top 25 Flood Events Station Jun Ju1 Au Se Oct Nov Dec Coon Creek at Riley 4 2 3 2 0 0 2 Kishwaukee River at Belvidere 1 0 2 0 0 0 0 1 South Branch Kishwaukee River 4 2 5 4 4 1 I 0 0 1 at De Kalb South Branch Kishwaukee River 2 4 8 1 1 1 3 3 0 1 . 0 1 near Fairdale Kishwaukee River near Perryville 2 6 9 2 1 1 2 1 0 0 0 1 Killbuck Creek near Monroe CeIiter 2 4 9 I 0 2 4 I 1 1 0 0 Drought and Low Flows Low flows in the Kishwaukee River basin are high compared to that in streams for most regions of lllinois. The higher than norrnallow flow characteristics are a result of shallow ground-water storage and its connection to nearby streams. The northern part of the Kishwaukee River basin has the greatest connection with shallow groundwater and has substantial low flow even during the most severe droughts. The South Branch Kishwaukee River has a lower sustained flow during drought years, more typical of other regions in northeastern and central TIlinois. 28 The 7-day low flow is the minimum daily average flow rate during a given year observed over a consecutive seven-day period. The 7-day, lO-year low flow (Q7,1O) is the 7-day low flow expected to occur on average only one out of every ten years. The Q7, I0 for the Kishwaukee River ranges from 7 cfs near Marengo to 78 cfs at the river's confluence with the Rock River (Singh, et ai., 1988). The Q7,10 value increases downstream as each tributary contributes flow, with the South Branch Kishwaukee River providing the greatest contribution (13 cfs). Low flows on the South Branch Kishwaukee River are lower than those for other portions of the Kishwaukee River basin. Without the effluent discharges from De Kalb and Sycamore, the Q7, lOon the South Branch Kishwaukee River would be close to zero for much of its upstream reach, continuing as far downstream as Genoa. Temporal Trends in Low Flows Figure 20 shows the annual series of 7-day low flows for five stream gages in the Kishwaukee River basin. Most of the flow records show an increasing trend over time. This is to be expected given the general increase in precipitation since 1970, as discussed earlier. The trend for the South Branch Kishwaukee River near Fairdale is most pronounced, and is caused not only by climatic influences but also by the increases in the amount of effluent discharges from nearby cities have grown. Currently over half of the low flow in the South Branch Kishwaukee River originates from these effluent discharges, primarily from the cities of De Kalb and Sycamore. Low flows will continue to increase as the population of these cities also increases. 1000,.------, 100' I· ~Coon Creek at Riley -w-Kishwaukee River at Belvidere -6-5. Sr. Kishw8ukee River at Dekalb -4-S. Bt. Klshwaukfle Rlwr near Fairdale _Klshwaukee River near PenyvlUe O.l1===:::===::;:==--_---_--~---J 1940 1950 1960 1870 1880 1190 2000 Figure 20. Seven-Day Low Flows for the Kishwaukee River and Tributaries 29 Results of the statistical trend analysis of the low flow records are given in Table 13. The results confirm the observations in Figure 20, with all gaging records showing an increase in low flows over the entire' period of record. All of the gages show a slight decrease in low flows since 1970, but this is not a statistically significant trend. Table 13. Trend Correlations for 7-Day Low Flows Kendall trend correlation Station Period of record for 7-da low flows Kishwaukee River at Belvidere 1939-1995 0.270 1939-1969 0.039 1970-1995 -0.093 South Branch Kishwaukee River near Fairdale 1939-1995 0.324 1939-1969 .0.138 1970-1995 -0.067 Kishwaukee River near Perryville 1939-1995 0.238 1939-1969 -0.143 1970-1995 -0.107 Table 14 lists the 7-day low flow and IS-month flows of major droughts for the Kishwaukee River at Belvidere and the South Branch Kishwaukee River near Fairdale. The most severe droughts on record, as denoted by the 18-month drought flow, occurred in 1940-41, 1955-56, and 1963-64. Low flows on the South Branch Kishwaukee River near Fairdale have slowly grown larger because of the increase in effluent discharges noted previously. Table 14. Low Flows and Drought Flows during Major Droughts (in cubic feet per second, cfs) . 18-month drought flows 7-dav low flows Drought vears Belvidere Fairdale Belvidere Fairdale 1940-1941 109 60 45.7 8.2 1944-1945 206 ·151 40.9 6.4 1953-1954 180 81 47.6 9.6 1955-1956 99 70 32.3 8.8 1958-1959 129 149 30.0 9.5 1963-1964 95 61 29.3 6.8 1976-1977 137 100 35.9 9.9 1988-1989 164 162 33.6 13.1 30 Sum!J1ary Since 1970 there has been a significant jump, an increase of over 50 percent, in the average annual flow in the Kishwaukee River basin. This increase in streamflow directly corresponds to a concurrent increase in average annual precipitation. There have been no observed trends in streamflows since the early 1970s, nor were there any observed trends in flow for the earlier period of record prior to 1970. There has also been a general increase in high flows and low flows related to the considerable jump in average streamflow amounts. However, the trend analysis indicates no overall increase in peak discharges. 31 Erosion and Sedimentation Instream Sediment Load Instream sediment load is the component of soil eroded in the watershed and from the streambanks that is transported to and measured at a gaging station. It indiCates the actual amount of soil generated upstream of the gaging station and eventually transported to downstream reaches of the river. Given the complex dynamic process of soil erosion, sediment transport, and deposition, it is very difficult to quantify how much of the soil eroded from uplands and streambanks actually moves to downstream reaches. The sediment transported by a stream is a relatively small percentage of the total erosion in the watershed. However, the amount of sediment transported by a stream is the most reliable measure of the cumulative results of soil erosion, bank erosion, and sedimentation in the watershed upstream of a monitoring station. There are four gaging stations in the Kishwaukee River basin where instream sediment was monitored for some time. Table 15 summarizes information about the monito'ring stations. As shown in Figure 21, two of these stations are located on the Kishwaukee River and the another two on the South Branch Kishwaukee River. TablelS. Sediment Monitoring Stations in the Kishwaukee River Basin USGS station Drainage are~ Station name num.ber s . mi.) Period of record Kishwaukee River at Belvidere 05438500 538 Oct. 198Q-Sept. 1982 South Branch Kishwaukee River 05439000 78 Oct. 1979-Sept. 1981 at De Kalb South Branch Kishwaukee River 05439500 387 Oct. 198Q-Sept. 1982 near Fairdale oo 1,099 Apr. 1979-Aug. 1990ססKishwaukee River near Perryville 0544 The U.S. Geological Survey (USGS) monitored sediment yield at the South Branch Kishwaukee River at De Kalb for two water years (1979-1981), and at the Kishwaukee River near Perryville for more than two water years (1979-1981). Data collected by the USGS were reported as daily average concentrations. Therefore, daily and annual , sediment loads at these stations can be calculated. 33 Soal e 1: 608880 O'!!!!!!!!!!!!!!!~.==;;;;;;;'!Z'!!!!!!!!!!~'~.==;;;;!;i'0!!!!!!!!!!!!!!!!!!!!2••1I •• O~!!!!!!!!!!~'~O===;;;';;]O~!!!!!!!!!!"'!!!!!I' 0;;;;;;;==;;;;;;;;,6.0 It I I ••• 1 • r • N Basin Boundary • Sediment Station Major Rivers and N Streams Figure 21. Sediment Monitoring Stations in the Kishwaukee River Basin Data were collected by the lllinois State Water Survey (ISWS) at the Kishwaukee River at Belvidere for two water years (1980-1982), at the Kishwaukee River near Perryville eight water years (1982-1990), and at the South Branch Kishwaukee River near Fairdale two water years (1980-1982). The sediment data collected by the ISWS were instantaneous weekly samples; only instantaneous sediment loads can be calculated, not average daily or annual sediment loads. Figures 22-25 show the variability of daily and instantaneous suspended sediment concentrations for all four monitoring stations. For the Kishwaukee River at Belvidere (Figure 22), concentrations varied from a low of 12 milligram per liter (mgll) to a high of 278 mgll. There is no significant trend in the data. For the Kishwaukee River near Perryville (Figure 23), concentrations varied from 4 mgll to 3,340 mgll over the twelve year period. Data at this station frequently show higher concentrations in June and July, and for some water years there were higher concentrations during winter season. For the South Branch Kishwaukee River at De Kalb (Figure 24), concentrations varied from a low of 10 mgll to a high of about 1,744 mgll. Higher concentrations occurred in June and July quite often according to data measured in two water years. For the South Branch Kishwaukee River near Fairdale (Figure 25), concentrations varied from a low of 3 mgll to a high of 964 mgll, with higher concentrations occurring during June and July. 1000 05438500 Kishwaukee River at Belvidere - -.- . - : .".,.. ------.. . 'II!.--..-. _.-:_.~- -- __ •. ~ _. .-."'II! _ ..:".. - _~. • 1 10/01180 10/01181 10/01182 Date Figure 22. Variability ofInstantaneous Suspended Sediment Concentrations for the Kishwaukee River at Belvidere 35 10000 05440000 Kisnwaukee River near Perryville monitored by USGS 1000 ------. -- . ------. -- . ----- 100 10 . ------. - . --- . - .... - . ------. - . -- 00 N ..,. on -a r- oo 0 00 t: r:::'" 00 00 ~ '"00 00 00 00 :::00 00 '" ..,0 0 ..,0 0 0 0 0 - - - -~ 0 0 -8 §'" ~ ~ Q; ~ 1§ Ci 23 - 0 Date ooסס1 oo Kishwaukee River near Perryville monitored by ISWSסס0544 1000 --- -. -. ------... • • = • • . . • .....r.•• ...... .... : ...... -: 'P' =-- .:1- ••• • S. 'Ii:"..:!Il 100 ...... ~- -~,:-, "'!.- - -- -~- ~ '~'.'. '='!':.... •:...... :~ ..e: ...-- ..CO- ...•• . . .. = .~ - .~..• • - ••-. ~ ••. -"E .. - ...... ;. • • . . 10 00 0 N ..,. on -a r- oo 00 00 00 '"00 00 00 ~ ~ 00 00'" t: '"t: Ci <:;- 0 ::: ;:; .., - -0 .., - - 0 ~ 25 1§ 2> Q; ~ 1§ 1§ ~ 0 § ~ 0 Date Figure 23. Variability ofinstantaneous Suspended Sediment Concentrations for the Kishwaukee River near Perryville, (a) USGS Data and (b) ISWS Data 36 10000 05439000 South Branch Kishwaukee River at De Kalb • 1000 - "!' • .. • • -. . · ~ . · . : ..•~-i~ . ':.;:~~~-- 100 ~"J:.'-:_~- -:.-~ ~::~:"";f~-~~ - -;~~~:- -Il\~+ ~ ~~ ...... • .. • ...... J! ". . ..~ .- i' 131I-_ • .. ..~r. . . _._ • ;. -,::. '!: • : 10 _____--II ____------ I IO/Oln9 09/30/80 10/01/81 Date Figure 24. Variability ofInstantaneous Suspended Sediment Concentrations for the South Branch Kishwaukee River at De Kalb ooסס1 05439500 South Banch Kishwaukee River near Fairdale 1000 . . ... -.. .I . - . .. ~.~.' ~:~ ~- ._ ...... -. ..~ 100 _.-~- -. ., \...... - - . : -:. .. 10 I 10101/80 10/01/81 10/01/82 Date Figure 25. Variability ofInstantaneous Suspended Sediment Concentrations for the South Branch Kishwaukee River near Fairdale 37 ------ Figures 26-30 show instantaneous sediment concentrations and loads for each water year monitored. Note the variability of streamflow (Qw), suspended sediment concentration (Cs), and suspended sediment load (Qs). Water years start on October I and end on September 30. Therefore, day I on the time scale is October I of the previous year. To provide values in tons per day, sediment load was computed by multiplying the daily water discharge by the instantaneous sediment concentrations and applying the proper unit conversion factors. For stations with weekly sediment sarnpling--the Kishwaukee River at Belvidere and the South Branch Kishwaukee River near Fairdale--it was not possible to compute average daily and annual sediment loads. However, instantaneous sediment load provides a range of values to compare variability of sediment from year to year and from station to station. For the Kishwaukee River at Belvidere, the sediment load varied from 7.4 tons per day to 1,036 tons per day. For the Kishwaukee River near Perryville, the sediment load varied from 1.6 tons per day to 24,000 tons per day. For the South Branch Kishwaukee River at De Kalb, the load varied from 0.04 ton per day to 3,070 tons per day. For the South Branch Kishwaukee River near Fairdale, sediment load varied from 1.4 tons per day to 4,860 tons per day. Note that sediment load depends on the size of the drainage area; therefore, a station with a larger drainage area will generally have a higher sediment load than one with a smaller drainage area under similar conditions. For this reason, the Kishwaukee River near Perryville had the highest sediment load of the four stations because it has the largest drainage area. Annual sediment load can only be calculated for the South Branch Kishwaukee River at De Kalb and the Kishwaukee River near Perryville. As shown in Table 16, the annual sediment load varied from a low of 9,248 tons to a high of 13,222 tons, with an annual average of 11,235 tons, at the South Branch Kishwaukee River at De Kalb, and from a low of91,755 tons to a high of 144,785 tons, with an annual average of 118,270 tons, at the Kishwaukee River near Perryville, respectively. The corresponding sediment yield per square mile ranged from 119 tons per square mile to 170 tons per square mile, with an average of 145 tons per square mile at the South Branch Kishwaukee River at De Kalb, and from 83 tons per square mile to 132 tons per square mile with an average of 108 tons per square mile at the Kishwaukee River near Perryville. Table 16. Annual Sediment Load for the South Branch Kishwaukee River at De Kalb and the Kishwaukee River near Perryville South Branch Kishwaukee River Kishwaukee River at De Kalb near Perryville Water Sediment Water Sediment discharge load discharge load Water ear cfs) (tons (cfs) (tons 1980 26,867 9,248 276,283 144,785 1981 20,822 13,222 254,629 91,755 38 (a) Waler Year 1981 5000 4000 .:s-;;; 3000 0'"' 2000 1000 0 300 200 QO 000 00 0 ".E- O 0 0 ~ 0 00 u 0 0 0 oCb 100 0 00 0 0 0 0 0 en 0 0 0 10 , , 0 1200 900 -~ ~'" ~ 600 ~ 0'" 0 0 0 300 0 0 0 0 0 0 50 100 150 200 250 300 350 400 Time (day) Figure 26. Instantaneous Suspended Sediment Loadfor the Kishwaukee River at Belvidere (a) Water Year 1981 and (b) Water Year 1982 39 ------(b) Water Year 1982 5000 4000 ~ 3000 ~ 0"'" 2000 1000 0 300 I ° ° - 200 - =0 0 .§." - 0°0 ~ °0 ° °0 ° ° U 0 OJ cP -rO° Go 0 O°Q) Oeo ° 100 0 ° ° 0 ° ° 0 I , I I. "I I I I , 0 1200 0 900 ~ ~ ::::: ~ 0 c 600 ° ~ ~ 0" 300 0 0 50 150 200 250 300 350 400 Time (day) Figure 26. Concluded 40 (a) Waler Year 1979 20000 15000 ~ ..:0,. 10000 0 5000 a 3000 , 2000 - ..§."" ~ u 1000 - J~ ~, a I I I , " , 25000 ~ ~ 20000 f ~ >.. :::;:'" 15000 I ~ ~ " 6 10000 ~ ~ 0- ~ ~ 5000 r ~ I I , , I I , .\t-. ,J , IU I a J. /tIJ a 50 100 150 200 250 300 350 400 Time (day) Figure 27. Instantaneous Suspended Sediment Loadfor the Kishwaukee River near Perryville with Data Collected by the USGSfor(a) Water Year 1979- (c) Water Year 1981 41 (b) Waler Year 1980 20000 15000 :E" ...=:..,., 10000 c::r 5000 0 3000 2000 - -..., ..§." u'" 1000 ,.... , I.~ ., ~ .l h. . \ ,111 ·flk " 0 25000 20000 ~ ~ 15000 ~ '"~ 2 10000 c::r '" 5000 0 0 50 100 150 200 250 300 350 400 Time (day) Figure 27. Continued 42 (e) Waler Year 1981 20000 15000 :§" -=: 10000 <:7'" 5000 0 3000 - 2000 - ".§."" ~ u 1000 - J.. .~LA ,~ ,,. 1 k,. 1 ;~L, , 1 .f. .• 1 1 .A 1 50 100 150 200 250 300 350 400 Time (day) Figure 27. Concluded 43 (a) Waler Year 1983 12000 10000 BOOO ~ ~ 6000 c:r'"' 4000 2000 0 4000 3000 ~<::: ..§."" 2000 a 1000 o 00 o 0 40000 30000 ~ ~ ~ ~ <= 20000 ~ ~ o c:r o ocP 10000 o O· 0 50 100 150 200 250. 300 350 400 Time (day) Figure 28. Instantaneous Suspended Sediment Loadfor the Kishwaukee River near Perryville with Data Collected by the ISWSfor (a) Water Year 1983 - (h) Water Year 1990 44 (b) 'Haler Year 1984 12000' 10000 BOOO -;;; ~ 6000 C>"'" 4000 2000 0 4000 3000 ' ".§."" 2000 ~ ~ u f 1000 - f- ~RJ , I -". I , rfh) 0 40000 30000 -;;:; -c ",''" ~ 0= 20000 ~ ~ C>" 10000 0 0 0 50 100 150 200 250 300 350 400 Time (day) Figure 28. Continued 45 (c) Waler Year 1965 12000 lOOOO BOOO ~ ~ 6000 CY'" , 4000 2000 0 4000 3005 ".§."" 2010 ~ u 1015 20 40000 I 30000 e -;:: :;;::'" ~ e- '" 20000 ~ I c~ 10000 - I '" ~q , I, ' I I 0 0 50 100 150 200 250 300 350 400 Time (day) Figure 28. Continued 46 (d) Waler Year 1986 12000 10000 8000 ~ $ 6000 0'"' 4000 2000 , , 0 4000 f 3000 I :;:: aD .E. 2000 l ~ u f 1000 l f hcoco ~n ,0 ~'"'" ~, 0 0 40000 30000 - -;;::; - ~'" ~ c 20000 - ~ ~ - 0 10000 l f [0 [ . , n. [ J [0.. , 0 -'"'"' "'--. 0 50 100 150 200 250 300 350 400 Time (day) Figure 28. Continued 47 . -. _.__ ._~ .... -.-._.-----_._- ------ (e) Water Year 1987 12000 10000 BOOO ~ ...::!.,. 6000 = 4000 2000 0 ' I I I 4000 0 3000 .§."" 2000 '"~ '-' 0 1000 ° 00, 0 0 40000 30000 >-. ::;:'" ~ co 20000 2 ~ 0 10000 - I ,,.., ,0 ~-, 0 0 50 100 150 200 250 300 350 400 Time (day) Figure 28. Continued 48 (f) Waler Year 1988 12000 10000 8000 = ~ 6000 =.. 4000 2000 0 4000 3000 "..§."" 2000 u= 1000 o 0 40000 30000 - ~ ~ 1-. ~ =~ 20000 "- ~ I 0= 10000 " .L~ I '" I O~ _ rR I I J., 0 0 50 100 150 200 250 300 350 400 Time (day) Figure 28. Continued 49 (g) Waler Year 1989 12000 10000 / . 8000 -;;; ~ 8000 0'" 4000 2000 0 4000 3000 :::..., .!§. 2000 ~ u 1000 ° 0, 0 40000 I 30000 ' ~ ~ ~ ~ 20000 I .::...c ~ 0 10000 - - . J _, .1 " 1 0 ~ 0 50 100 150 200 250 300 350 400 Time (day) Figure 28. Continued 50 (h) Waler Year 1990 12000 10000 6000 -;;; ~,. 6000 0' 4000 2000 0 4000 3000 aD "E 2000 ~ '-' o 1000 0 40000 f 30000 ' ~ ~'" ~ c 20000 - 6 ~ 0' 10000 - o I 0_ I, , 0 0 50 100 150 200 250 300 350 400 Time (day) Figure 28. Concluded 51 (a) Waler Year 1980 1500 1000 SOD 0 2000 ~ 1500 l .,. 1000 .E-"., '-' 500 I\J. ~ .,,.... f , ''1\ .At 1. I ,A. , I ~.v " 0 \J 4000 3000 ~ '" ~., ~ 2000 - ..::.., C>" 1000 .1 ,~.,L, 1 '" I , 1 , • I I \1 0 0 50 100 150 200 250 300 350 400 Time (day) Figure 29. Instantaneous Suspended Sediment Loadfor the South Branch Kishwaukee River at De Kalb (a) Water Year 1980 and (b) Water Year 1981 52 . (b) Waler Year 1981 1500 1000 500 0 2000 l 1500 QO "..§. 1000 ~ t '-' - 500 - ~ , ,~,~I... ~ . I ~ '1' ,,' j 0 • 4000 3000 ~ ~ - ~ ~ c 2000 6 ~ - C7 1000 - , I I I , I, , 0 0 50 100 150 200 250 300 350 400 Time (day) Figure 29. Concluded 53 (a) Waler Year 1981 4000 3000 ~ ~ 2000 0''" 1000 0 1000 800 0 600 co ~ "' ~ 400 '-' ° 200 to,~ ~, 0 1 r a! 0 °, 4000 3000 ~ ~ ~ ~ c 2000 ° ~ ~ ° 0' 1000 ° 0 0 50 100 150 200 250 300 350 400 Time (day) Figure 30. Instantaneous Suspended Sediment Loadfor the South Branch Kishwaukee River near Fairdale (a) Water Year 1981 and (b) Water Year 1982 54 (b) Waler Year 1982 4000 3000 3" ~,. 2000 0 1000 a 1000 0 BOO BOO "..s.." ~ 400 ° 200 °0°'00 c90 0cr:;PQPj:!° Cb °ctR::o CP ° a I ° , "I ' ° , ' ° 4000 3000 c o -;::; ~ ~ ~ ~ ~ c 2000 ~ ~ & ° 1000 " n , ,I--n ri:J:h '"' '"'-,-.. r,...,1° L a I n--- I a 50 100 150 200 250 300 350 400 Time (day) Figure 30. Concluded 55 Sedimentation Sedimentation is the process by which eroded soil is deposited in stream channels, lakes, wetlands, and floodplains. In natural systems that have achieved dynamic equilibrium, the rates of erosion and sedimentation are in balance over a long period of time. This results in a stable system, at least until disrupted by extreme events. However, in ecosystems where there are significant human activities such as fanning, construction, and hydraulic modifications, the dynamic equilibrium is disturbed, resulting in increased rates of erosion in some areas and a corresponding increased rate of sedimentation in other areas. Erosion rates are measured by estimating soil loss in upland areas and measuring streambank and bed erosion along drainageways. These measurements are generally not very accurate and thus are estimated indirectly, most often through evaluation of sediment transport rates based on instream sediment measurements and empirical equations. Similarly, measurement of sedimentation rates in stream channels is very difficult and expensive. Lake sedimentation surveys provide the most reliable sedimentation measurements. Since lakes are typically created by constructing dams across rivers; creating a stagnant or slow-moving body of water, they trap most of the sediment that flows into them. The continuous accumulation of eroded soils in lake beds provides a good measure of how much soil has been eroded in the watershed upstream of the lake. 56 Water Use and Availability Statewide, water use has increased a modest 27% since 1965 (lliinois Department of Energy and Natural Resources, 1994). Most of that increase is in power generation. PWS use has risen only about 7%, less than the concurrent increase in population. The number of public ground-water supply facilities in lllinois has risen significantly during that time, yet the total amount supplied by ground water remains near 25%. A dependable, adequate source of water is essential to meeting existing and potential population demands and industrial uses in lllinois. Modifications to and practical management of both surface and ground-water use have helped make lllinois' water resources reliable. As individual facilities experience increases in water use, innovative alternative approaches to developing adequate water supplies must be developed, such as use of both surface and ground waters. Major metropolitan centers such as the Chicago area, Peoria, and Decatur have already developed surface and ground-water sources to 'meet their development needs and to sustain growth. The construction of impounding reservoirs has become and will remain economically and environmentally expensive, making it a less common approach. Proper management of water resources is necessary to ensure a reliable, high quality supply for the population. Water conservation practices will become increasingly important to reduce demand and to avoid exceeding available supplies. Both our ground water resources and surface reservoir storage must be preserved to maintain reliable sources for future generations. Ground-Water Resources Ground water provides approximately one-third of Dlinois' population with drinking water. The sources of this water can be broken down into three major units: I) sand and gravel, 2) shallow bedrock, and 3) deep bedrock. Most ground-water resources are centered in the nonhern two-thirds of Dlinois. Sand-and-gravel aquifers are found along many of the major rivers and streams in the state and also in "buried bedrock valley" systems created by complex glacial and interglacial episodes of surface erosion. There are also many instances of thin sand-and gravel deposits in the unconsolidated materials above bedrock. These thin deposits are used throughout lllinois to meet the water needs of small towns. Shallow bedrock units are more commonly used in the northern third of lliinois, whereas deep bedrock units are most widely used in the nonheastern quarter (in and around the Chicago area). The variety of uses and the volume of water used vary widely throughout the state. This report describes ground-water availability and use in the Kishwaukee River basin. 57 Data Sources Private Well Information The Dlinois State Water Survey (ISWS) has maintained well construction reports since the late 1890s. Selected information from these documents has beeri computerized and is maintained in the Private Well Database. These data are easily queried and summarized for specific needs and form the basis of well distribution studies in the area. Public Well Information. Public Water Supply (PWS) well information has been maintained at the ISWS since the late 1890s. Municipal well books (or files) have been created for virtually all of the reported surface and ground-water PWS facilities in lllinois. Details from these files are assembled in the Public-Industrial-Commercial Database, which was created to house water well and water use information collected by the ISWS. Ground-Water Use Information The water use data given in this report come from the records compiled by the ISWS' Dlinois Water Inventory Program (IWIP). This program was developed to document and facilitate planning and·management of existing water resources in Dlinois. Information is collected through an annual water use summary mailed directly to each PWS facility. Data Limitations Several limitations must be taken into consideration when interpreting these data: I. Information is reported by drillers and each PWS facility. 2. Data measuririg devices are generally not very accurate. 3. Participation in the IWIP is voluntary. Information assembled from well construction reports and from the IWIP is considered . "reported" information. This means that the data are as accurate as the reliability of the individual reporting or as mechanical devices dictate. The quality of the reported information depends upon the skill or budget of the driller or facility, respectively. Moreover, the ISWS estimates that only one-third to one-half of the wells in the state are on file at the Survey, mainly due to the lack of reporting regulations prior to 1976. In general, water use measuring devices, such as the meters used by PWS facilities, are not very accurate. In fact, errors of as much as 10% are not uncommon. Much of the information reported in the IWIP is estimated by the water operator or by program staff. Participation in the program is not required by the State of Dlinois, and each facility voluntarily reports its information through a yearly survey. However, not all facilities know of or respond to the water use questionnaire. After several mail and telephone attempts have been made to gather this information, estimates are made using various techniques. To help reduce errors associated with the program, reported water use information is checked against usage from previous years to identify any large-scale reporting errors. 58 Ground-Water Availability The Kishwaukee River basin encompasses portions of three counties: Boone, McHenry, and Kane. The portions of each county in the watershed vary from 5% (Kane County) to 33% (McHenry County). This section summarizes ground-water availability in the area, considering only the portions of each county actually in the watershed. Domestic and Farm Wells Available regional information indicates that ground water for domestic and farm use in the basin is primarily obtained from wells finished in both sand and gravel deposits within the unconsolidated materials and in the bedrock. Good sources of ground water can be found in the cracked and creviced dolomite aquifers of shallow bedrock units as well as the deep sandstone systems in areas where shallower units lack sufficient capacity (Bergstrom et al., 1955). Table 17 summarizes the number of reported private wells in the basin by county and depth. Table 17. Reported Private Wells in the Kishwaukee River Basin (Source: ISWS Private Well Database) Depth range, feet Count 0-50 51-100 101-150 151-200 201-250 251-300 301-350 351-400 400+ Boone 14 25 25 24 4 6 2 o 1 Kane 4 51 5 7 27 20 11 5 4 McHenry 370 434 471 457 487 241 87 40 58 Total 388 510 501 488 518 267 100 45 63 Public Water Supply Wells Information from the ISWS Public-Industrial-Commercial database indicates that most ground water for PWS use in the watershed is obtained from wells finished in unconsolidated systems, which supply 91 % of the ground water withdrawn. The Cambrian-Ordovician systems supply almost 7%, with the remaining 2% coming from the Silurian system in the area. Unconsolidated wells range in depth from 40 to 231 feet, while bedrock wells range in depth from 230 to 1,293 feet. The remaining facilities withdraw 1.23 million gallons per day (mgd) for residential use, servicing a reported 5J,376 residents with an average per capita use of 88.2 gallons per day (gpd). 1995 Ground·Water Use Ground water constitutes a substantial portion of the total water used in the Kishwaukee River basin. Total ground-water use in the basin is estimated to be 3.01 mgd, with 1.23 mgd for PWS facilities, 0.76 mgd for self-supplied industry (8SI), 0.76 mgd for rural/domestic uses, and 0.26 mgd for livestock watering. 59 Public Water Supply In 1995, municipal residential use for 6 communities using ground water was reported to be 1.23 mgd, serving a combined population of 51,376. The average per capita use of these municipalities is 88.2 gpd. Self-Supplied Industry Self-supplied industries are defined as those facilities that meet all or a portion of their water needs from their own sources. In the Kishwaukee River basin, 14 such facilities reported pumping 0.76 mgd of ground-water in 1995. RurallDomestic There is no direct method for determining rural/domestic water use in the area. In order to get a rough estimate of this type of use, several assumptions were made using existing information. Reported population served and number of services from PWS facilities were used to calculate an average population per service for all PWS facilities in the basin. This number was used as an estimate of population per reported domestic well. The average PWS per capita use was then used as a multiplier to determine total rural/domestic water use from each well. The ISWS Private Well Database shows 2,880 reported wells in the watershed, an average of 3.0 people per service (well), and an average of 88.2 gpd per person; therefore, total rural/domestic water use was estimated to be 0.76 mgd. Livestock Watering Water withdrawals for livestock use in 1995 were estimated to be 0.26 mgd. Water use estimates for livestock are based on a fixed amount of water use per head for each type of animal. Percentages of the total animal population (lliinois Department of Agriculture, 1995) for the major livestock (cattle and hogs) in the counties were calculated based upon the percentage of county acres in the basin. Daily consumption rates (beef cattle = 12 gpd, all other cattle =35 gpd, and hogs =4 gpd) provided the basis for these calculations. Ground-Water Use Trends Ground-water use in the Kishwaukee River basin has remained relatively stable over the last six years. During this period, total ground-water use averaged 1.87 mgd and ranged from 1.77 to 1.99 mgd; PWS use averaged 1.08 mgd and ranged from 1.00 to 1.23 mgd; and 551 use averaged 0.80 mgd and ranged from 0.76 to 0.89 mgd. Table 18 shows the individual totals per year since 1990. No significant trends are evident in terms of water withdrawals from the watershed. 60 Table 18. Ground-Water Use Trends in the Kishwaukee River Basin (in million gallons per day, mgd) Year PWS SSI Total 1990 1.03 0.89 1.92 1991 1.06 0.79 1.85 1992 1.00 0.77 1.77 1993 1.10 0.77 1.87 1994 1.04 0.80 1.84 1995 1.23 0.76 2.11 Average 1.08 0.80 1.87 Surface Water Resources The rivers, streams, and lakes of the Kishwaukee River basin serve a wide variety of purposes, including public water supply, recreation (boating, fishing, and swimming), and habitat for aquatic life. The primary focus of this section is on water withdrawn from streams for public, industrial, and agricultural water supply, and the surface water resources available for such use. Water Supply Use The only present use of surface water in the basin is for self-supplied industrial use (55!), as all public water supplies (PW5) use ground water. The industrial use of water in the basin is withdrawn and discharged to supply ponds which are fed by shallow ground water, and thus is not directly connected to streams. The amount of surface water use has remained constant over the last six years. Table 19 shows the individual totals since 1990. Table 19. Surface Water Use Trends in the Kishwaukee River Basin (in million gallons per day, mgd) Year PWS 551 Total 1990 0.00 1.47 1.47 1991 0.00 1.40 1.40 1992 0.00 1.44 1.44 1993 0.00 1.46 1.46 1994 0.00 1.48 1.48 1995 0.00 1.58 1.58 Average 0.00 1.47 1.47 61 Potential for Development of Additional Surface Water Sources Water supply systems generally obtain surface water in one of three manners: I) direct withdrawal from a stream, 2) impoundment of a stream to create a storage reservoir, or 3) creation of an off-channel (side-channel) storage reservoir into which stream water is pumped. As described below, potential locations for direct withdrawals and impounding reservoirs are somewhat limited geographically. The potential for side-channel storage exists along most streams. Direct Withdrawals from Streams Most of the surface water supply systems in the basin require a constant supply of water. For a stream to be used for this purpose, it is essential that the stream have a continuous flow of water during extreme drought conditions. In the Kishwaukee River basin, most of the largest streams have such a consistent flow. The potential exists for these rivers to support direct withdrawals; however, this is unlikely to happen unless large withdrawal rates are required, since ground-water resources in the area are generally sufficient to meet smaller water use needs. hnpounding Reservoirs There is only one impounding reservoir in the Kishwaukee River basin that has a surface area in excess of 40 acres: Candlewick Lake in western Boone County. The lake is used primarily as a site for residential development. Dawes and Terstriep (1966) identify one potential reservoir site in the Kishwaukee River basin, on Mosquito Creek, also in western Boone County. This potential reservoir is relatively small, with a surface area of 112 acres and a water supply yield of only I mgd. Side-Channel Reservoirs There are no known side-channel reservoirs in the Kishwaukee River basin. The construction of side-channel reservoirs is generally not limited by local topography and is a viable water supply option along most streams in the basin. The potential need for such reservoirs is small, however, because of the sufficient ground-water resources in the basin. 62 Ground-Water Quality This section examines ground-water quality records to determine temporal trends and to provide baseline water quality parameters in the Kishwaukee River basin. Increasingly, ground-water contamination is discussed in the news media, and it may seem that the entire ground-water resource has been affected. However, these contamination events are often localized and may not represent widespread degradation of the ground-water resource. By examining the temporal trends in ground-water quality in'the area, it may be possible to determine whether large-scale degradation of the ground-water resource has occurred. The general term "ground-water quality" refers to the chemical composition of ground water. Ground water originates as precipitation that filters into the ground. As the water infiltrates the soil, it begins to change chemically due to reactions with air in the soil and \ with the earth materials through which it flows. Human-induced chemical changes can also occur. In fact, contamination of ground water is generally the result of human induced chemical changes and not naturally occurring processes. As a general rule, local ground-water quality tends to remain nearly constant under natural conditions because of long ground-water travel times. Therefore, significant changes in ground-water quality can indicate degradation of the ground-water resource. Data Sources The ground-water quality data used in this report come from two sources: private wells and municipal wells. The private well water quality data are compiled by the Chemistry Division of the lllinois State Water Survey (lSWS) as part of its water testing program and are maintained by the Office of Ground-Water Information in a water quality database. The municipal well data come from ISWS ll!lalyses and from the lllinois Environmental Protection Agency (IEPA) laboratories. The combined database now contains more than 50,000 records of chemical analyses from samples analyzed at the ISWS and IEPA laboratories. Some of these analyses date to the early part of the century, but most are from 1970 to the present. Before 1987, most analyses addressed inorganic compounds and physical parameters. Since then, many organic analyses have been added to the database from the IEPA Safe Drinking Water Act compliance monitoring program. This report presents information for only a portion of the chemical parameters in the ISWS database. 63 Data Limitations Several limitations must be understood before meaningful interpretation of the water quality data can begin: 1. Representativeness of the sample 2. Location information 3. Data quality (checked by charge balance) 4. Extrapolation to larger areas I Generally, private well samples are not representative of regional ground-water quality. I In most cases, private well owners submit samples for analysis only when they believe there may be a problem such as high iron or an odd odor or taste. However, while one or I more constituents may not be representative, in general the remainder of the chemical information will be accurate and useful. As a result, the composite data may be skewed I toward analyses with higher than normal concentrations. On the other hand, private well information probably gives a better picture of the spatial , distribution of chemical ground-water quality than municipal well information because of the larger number of samples spread over a large area. Recent IEPA data from municipal wells will not be skewed because each well is sampled and analyzed on a regular basis. While this produces a much more representative sample overall, samples are generally limited to specific areas where municipalities are located. Therefore, these data may not be good indicators of regional ground-water quality. Much of the location information for the private wells is based solely on the location provided by the driller at the time the well was constructed. Locations are usually given to the nearest IO-acre plot of land. For this discussion, that degree of resolution is adequate. However, it is not uncommon for a given location to be in error by as much as six miles. To circumvent possible location errors, this report presents results on a watershed basis. The validity of water quality data was not checked for this report. However, previous charge balance checking of these data was conducted for a similar statewide project (lliinois Department of Energy and Natural Resources, 1994). Charge balance is a simple measure'of the accuracy of a water quality analysis, It measures the deviation from the constraint of electrical neutrality of the water by comparing total cations (positively charged ions) with total anions (negatively charged ions). Because many of the early analyses were performed for specific chemical constituents, a complete chemical analysis is not always available from which to calculate a charge balance. 64 ------,------ The statewide study searched the water quality database for analyses with sufficient chemical constituents to perform an ion balance. The charge balance checking of those data found that more than 98% of the analyses produced acceptable mass balance, which suggests that the chemical analyses are accurate in the database. Using that assumption ~ for this report, we feel confident that most of the analyses used are accurate and give representative water quality parameters for the Kankakee River basin. However, this may be true only for large samples, a factor that should be considered when reviewing the results, as this report presents data for ten decades and a wide range of sample sizes. Extrapolating a point value (a well water sample) to a regional description of ground water quality is difficult theoretically and beyond the scope of this report. However, none of the data provide a uniform spatial coverage. Therefore, it seems best to summarize the data on a watershed basis to ensure an adequate number of values. The private well analyses are more numerous and will likely provide better spatial coverage than the municipal well data, which are concentrated in isolated locations. Chemical Components Selected for Trend Analysis In many cases, ground~water contamination involves the introduction into ground water of industrial or agricultural chemicals such as organic solvents, heavy metals, fertilizers, and pesticides. However, recent evidence suggests that many of these contamination occurrences are localized and form finite plumes that extend down gradient from the source. Much of this information is relatively recent, dating back a few decades, and long-term records at anyone site are rare. As mentioned earlier, changes in the concentrations of naturally occurring chemical elements such as chloride, sulfate, or nitrate also can indicate contamination. For instance, increasing chloride concentrations may indicate contamination from road salt or oil field brine, while increasing sulfate concentrations may be from acid wastes such as metal pickling, and increasing nitrate concentrations may result from fertilizer application, feed-lot runoff, or leaking septic tanks. These naturally occurring substances are the major components of mineral quality in ground water and are routinely included in ground-water quality analyses. Fortunately, the ISWS has maintained records of routine water quality analyses of private andcomrnercial wells that extend as far back as the 1890s. After examination of these records, six chemical constituents were chosen for trend analyses based on the large number of available analyses and because they may be indicators of human-induced degradation of ground-water quality. These components are iron (Fe), total dissolved solids (IDS), sulfate (S04), nitrate (N03), chloride (CI), and hardness (as CaC03). 65 Aquifer Unit Analysis Ground water occurs in many types of geological materials and at various depths below the land surface. This variability results in significant differences of natural ground-water quality from one part of lllinois to another and from one aquifer to the next even at the same location. For the purpose of this trend analysis, wells that were finished in the unconsolidated sand and gravel units were grouped together, as were wells finished in the bedrock units. The unconsolidated units are by far the most frequently used in the Kankakee River basin. Out of the more than 2,880 private wells reported in the basin, only 468 indicate penetration into the bedrock units. From the water quality analyses in the ISWS water quality database, only 178 of 34 wells indicated that the water for the sample came from the bedrock units. In this report. unconsolidated and bedrock aquifers are treated separately in the descriptions of each chemical constituent. Discussion and Results The temporal trends of the six chemical constituents from the unconsolidated materials are summarized in this section. Tables 20 and 21 present the results of each decade's analyses, including the maximum, minimum, mean, and median for each of the six chemical constituents for unconsolidated and bedrock materials, respectively. Median values are given in the tables by decade, beginning with 1900-1909 (Decade 0), 1910-1919 (Decade I), and so on through the 1990s (Decade 9). Each decade covers· the corresponding ten-year period, except for the partial decade of the 1990s. Median concentrations are given per decade so that temporal trends can be identified in the data set. Median values are the midpoints of a set of data, above which lie half the data points and below which is found the remaining half. These values are used to look at the central tendency of the data set. Although the arithmetic mean would also look at this statistic, it incorPorates all data points into its analysis, which can move the mean value in one direction or another based upon maximum or minimum values. Outliers occur in many data sets. These are extreme values that tend to stand alone from the central values of the data set. They may lead to a false interpretation of the data set, whereas the median values are true values that are central to the data set. By looking at the median we can detemiine trends in the central portions of the data. However, for data sets with a small number of samples, the median may not necessarily be representative of the water quality in the area. It is important to recognize that the values included in the table are reported values. While every attempt to verify the values was made, the validity of each value with regard to method error, etc. is not known. For this reason, Tables 20 and 21 include every analysis in the database and all analysis results regardless of whether a value seems excessive and regardless of the sample size in the decade. 66 Table 20. Chemical Constituents Selected for Trend Analysis, Unconsolidated Systems Decade" Chemical constiment 0 2 3 4 5 6 7 8 9 Iron (Fe) Sample size (N) 0 2 0 3 8 5 17 50 22 0 Minimum (mgll) 0.0 0.1 0.0 1.3 0.0 0.7 0.2 0.0 0.1 0.0 Maximum (mgll) 0.0 0.8 0.0 12.0 4.8 5.3 12.0 5.8 36.5 0.0 Mean (mgll) 0.0 0.5 0.0 5.4 1.0 2.1 2.5 1.4 3.8 0.0 Median (mgll) 0.0 0.5 - 0.0 3.0 0.3 1.3 0.9 1.0 1.7 0.0 IDS Sample size (N) 0 4 0 3 8 5 17 50 21 0 Minimum (mgll) 0.0 392.0- 0.0 340.0 335.0 361.0 357.0 296.0 262.0 0.0 Maximum (mgll) 0.0 532.0 0.0 532.0 451.0 529.0 585.0 1276.0 2480.0 0.0 Mean (mgll) 0.0 471.0 0.0 426.7 388.6 411.8 426.9 484.6 696.4 0.0 Median (mgll) 0.0 480.0 0.0 408.0 377.0 396.0 409.0 449.0 457.0 0.0 Sulfate (SO.) Sample size (N) 0 3 0 3 5 3 1 22 22 0 Minimum (mgll) 0.0 23.0 0.0 0.0 12.0 20.0 82.0 31.3 10.0 0.0 Maximum (mgll) 0.0 120.0 0.0 129.0 83.0 77.0 82.0 244.0 422.0 0.0 Mean (mgll) 0.0 65.3 0.0 58.3 59.8 40.3 82.0 78.6 96.3 0.0 Median (mgll) 0.0 53.0 0.0 46.0 68.0 24.0 82.0 71.0 58.2 0.0 Nitrate (N03) Sample size (N) 0 3 0 3 3 2 12 43 4 0 Minimum (mgll) 0.0 2.1 0.0 1.1 1.9 0.4 0.0 0.0 0.2 0.0 Maximum (mgll) 0.0 23.8 0.0 11.9 12.6 0.9 2.8 151.0 26.1 0.0 Mean (mgll) 0.0 9.8 0.0 5.1 5.8 0.7 1.0 17.0 6.9 0.0 Median (mgll) 0.0 3.6 0.0 2.3 2.8 0.7 0.9 1.2 0.7 0.0 Chloride (CI) Sample size (N) 0 4 0 3 8 5 16 50 22 0 Minimum (mgll) 0.0 10.0 0.0 8.0 1.0 3.0 1.0 0.0 1.0 0.0 Maximum (mgIl) 0.0 64.0 0.0 9.0 21.0 11.0 30.0 345.0 830.0 0.0 Mean (mgll) 0.0 29.5 0.0 8.3 9.2 6.6 13.0 32.2 110.2 0.0 Median (mgll) 0.0 22.0 0.0 8.0 9.5 5.0 10.5 23.0 27.5 0.0 Hardness (as CaCO,) Sample size (N) 0 2 0 3 8 5 17 48 12 0 Minimum (mgll) 0.0 375.0 0.0 300.0 228.0 347.0 321.0 14.0 222.0 0.0 Maximum (mgll) 0.0 445.0 0.0 432.0 423.0 434.0 524.0 672.0 603.0 0.0 Mean (mgll) 0.0 410.0 0.0 374.7 345.4 371.4 379.3 382.3 410.2 0.0 Median (mgll) 0.0 410.0 0.0 392.0 346.5 352.0 364.0, 375.0 375.5 0.0 *Note: Decade 0=1900-1909, Decade 1=1910-1919, and so on. 67 Table 21. Chemical Constituents Selected for Trend Analysis, Bedrock Aquifer Systems Decade" Chemical constituent 0 2 3 4 5 6 7 8 9 Iron (Fe) Sample size (N) 1 0 0 6 2 I 5 14 7 2 Minimum (mgll) 0.8 0.0 0.0 0.0 1.5 2.0 0.0 0.0 0.0 0.2 Maximum (mgll) 0.8 0.0 0.0 2.4 1.8 2.0 4.7 25.0 5.9 0.2 Mean (mgll) 0.8 0.0 0.0 0.7 1.6 2.0 1.6 2.8 1.0 0.2 Median (mgll) 0.8 0.0 0.0 0.4 1.6 2.0 1.5 1:4 0.2 0.2 IDS Sample size (N) I 0 0 6 2 1 5 14 7 2 Minimum (mgll) 290.0 0.0 0.0 260.0 326.0 375.0 370.0 304.0 297.0 320.0 Maximum (mgll) 290.0 0.0 0.0 729.0 366.0 375.0 493.0 492.0 533.0 337.0 Mean (mgll) 290.0 0.0 0.0 386.3 346.0 375.0 430.0 396.9 391.4 328.5 Median (mgll) 290.0 0.0 0.0 336.5 346.0 375.0 433.0 393.0 377.0 328.5 Sulfate (SO.) Sample size (N) 1 0 0 6 2 0 0 5 6 2 Minimum (mgll) 3.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.5 10.0 Maximum (mgll) 3.0 0.0 0.0 42.0 8.0 0.0 0.0 49.0 20.0 10.0 Mean (mgll) 3.0 0.0 0.0 8.5 4.0 0.0 0.0 10.8 10.4 10.0 Median (mgll) 3.0 0.0 0.0 2.5 4.0 0.0 0.0 1.0 10.0 10.0 Nitrate (NO,) Sample size (N) 1 0 0 6 1 0 3 6 I 0 Minimum (mgll) 0.0 0.0 0.0 0.4 2.0 0.0 0.7 0.0 1.4 0.0 Maximum (mgll) 0.0 0.0 0.0 2.4 2.0 0.0 1.2 0.6 1.4 0.0 Mean (mgll) 0.0 0.0 0.0 1.4 2.0 0.0 1.0 0.2 1.4 0.0 Median (mgll) 0.0 0.0 0.0 1.4 2.0 0.0 1.0 0.2 1.4 0.0 Chloride (CI) . Sample size (N) 1 0 0 6 2 1 5 . 14 7 2. Minimum (mgll) 2.0 0.0 0.0 1.0 1.0 2.0 1.0 0.0 1.5 1.0 Maximum (mgll) 2.0 0.0 0.0 4'.0 2.0 2.0 46.0 5.0 33.0 1.1 Mean (mgll) 2.0 0.0 0.0 3.2 1.5 2.0 19.0 2.1 7.7 l.l Median (mgll) 2.0 0.0 0.0 4.0 1.5 2.0 3.0 2.5 4.0 1.1 Hardness (as CaCO,) Sample size (N) I 0 0 6 2 1 5 14 5 0 Minimum (mgll) 196.0 0.0 0.0 118.0 330.0 255.0 16.0 4.0 10.0 0.0 Maximum (mgll) 196.0 0.0 0.0 351.0 337.0 255.0 444.0 402.0 272.0 0.0 Mean (mgll) 196.0 0.0 0.0 234.7 333.5 255.0 244.0 194.6 153.6 0.0 Median (mgll) 196.0 0.0 0.0 238.0 333.5 255.0 292.0 248.0 205.0 0.0 "Nole: Decade 0=1900-1909, Decade 1=1910-1919, and so on. 68 Due to the lack of long-tenn historical data, a ground-water trend analysis has not been developed for the Kishwaukee River basin. The available data indicates that the parameters show either stable levels of concentrations or fluctuations presumably caused by inadequate sample sizes. To keep within the fonnat set by previous reports, topical infonnation is presented for the six parameters. Although no analysis other than these discussions are given in the text, summary statistics are shown in Tables 14* and 14*. Iron (Fe) Iron in ground water occurs naturally in the soluble (ferrous) state. However, when exposed to air, iron becomes oxidized into the ferric state and fonns fine to fluffy reddish-brown particles that will settle to the bottom of a container if allowed to sit long enough. The presence of iron in quantities much greater than 0.1 to 0.3 milligrams per liter (mgll) usually causes reddish-brown stains on porcelain fixtures and laundry. The drinking water standards recommend a maximum limit of 0.3 mgll iron to avoid staining (Gibb, 1973). Total Dissolved Solids (TDS) The IDS content of ground water is a measure of the mineral solutes in the water. Water with a high mineral content may taste salty or brackish depending on the types of minerals in solution and their concentrations. In general, water containing more than 500 mgll IDS will taste slightly mineralized. However, the general public can become accustomed to the taste of water with concentrations of up to 2,000 mgll. Water containing more than 3,000 mgll IDS generally is not acceptable for domestic use, and at 5,000 to 6,000 mgll, livestock should not drink the water. Because IDS concentration is a lumped measure of the total amount of dissolved chemical constituents in the water, it will not be a sensitive indicator of trace-level contamination. However, it is a good indicator of major inputs of ions or cations to ground water. Water with high sulfate concentrations often has a medicinal taste and a pronounced laxative effect on those not accustomed to it. Sulfates generally are present in aquifer systems in one of three fonns: as magnesium sulfate (sometimes called Epsom salt); as sodium sulfate (Glauber's salt); or as calcium sulfate (gypsum). They also occur in earth materials in a soluble fonn that is the source for natural concentrations of this compound. Human sources similar to those for chloride also can contribute locally to sulfate concentrations. Coal mining operations particularly are a common source of sulfate pollution, as are industrial wastes. Drinking water standards recommend an upper limit of 250 mgll for sulfates. Upward trends in sulfate concentrations can suggest potential ground-water pollution. 69 Nitrates are considered harmful to fetuses and children under the age of one when concentrations in drinking water supplies exceed 45 mgll (as N03), or the approximate equivalent of 10 mgll nitrogen (N). Excessive nitrate concentrations in water may cause "blue baby" syndrome (methmoglobinemia) .when such water is used in the preparation of infant feeding formulas. Inorganic nitrogen fertilizer has proven to be a source of nitrate pollution in some shallow aquifers, and may become an even more significant source in the future as ever increasing quantities are applied to lllinois farmlands.. Upward trends in concentrations of nitrate may be a good indication that farm practices in the area are affecting the ground-water environment. Chloride (CI) Chloride is generally present in aquifer systems as sodium chloride or calcium chloride. Concentrations greater than about 250 mgll usually cause the water to taste salty. Chloride occurs in earth materials in a soluble form that is the source for normal concentrations of this mineral in water. Of the constituents examined in this report, chloride is one of the most likely to indicate the impacts of anthropogenic activity on ground water. Increasing chloride concentrations may indicate contamination from road salt or oil field brine. The drinking water standards recommend an upper limit of 250 mgll for chloride. In sand and gravel aquifers throughout most of the state, chloride concentrations are usually less than 10 mgll. Hardness (as CaC03) Hardness in water is caused by calcium and magnesium. These hardness-forming minerals generally are of major importance to users since they affect the consumption of soap and soap products and produce scale in water heaters, pipes, and other parts of the water system. The drinking water standards do not recommend an upper limit for hardness. The distinction between hard and soft water is relative, depending on the type of water a person is accustomed to. The ISWS categorizes water from 0 to 75 mgll as soft, 75 to 125 mgll as fairly soft, 125 to 250 mgll as moderately hard, 250 to 400 mgll as hard, and over 400 mgll as very hard. Summary This work was undertaken to examine long-term temporal trends in ground-water quality in the Kishwaukee River basin. Data from private and municipal wells were the primary sources of information used to show the trends in six chemical constituents of ground water in the area These data demonstrate that on a watershed scale, ground water has not been degraded with respect to the six chemicals examined. Fluctuations from one decade to the next are more likely related to data limitations than to any inherent changes in ground-water quality. It is also evident that the sample size in each decade can playa role in trend analysis. 70 ------._------ Much of the contamination of illinois' ground water is localized. Nonetheless, this contamination can render a private or municipal ground-water supply unusable. Once contaminated, ground water is very difficult and expensive to clean, and clean-up may take many years to complete. Clearly it is in the best interests of the people of illinois to protect their ground-water resource through prevention of contamination. 71 References Introduction lllinois Department of Natural Resources. 1996. lllinois Land Cover, An Atlas. IDNR 96/05. Springfield, ll... lllinois Department of Natural Resources. 1996. lllinois Land Cover, An Atlas. Compact Disc. Springfield, ll... Leighton, M.M., G.E. Ekblaw, and L. Horberg. 1948. Physiographic Divisions of lllinois. lllinois State Geological Survey Report of Investigation 129. Champaign, ll... Mattingly, R.L., and E.E. Herricks. 1991. Channelization of Streams and Rivers in lllinois: Procedural Review and Selected Case Studies. lllinois Department of Natural Resources Report n..ENRIRE-WR-91/01. Runge, E.C.A., L.E. Tyler, and S.G. Carmer. 1969. Soil Type Acreages for lllinois: University of llIinois Agricultural Experiment Station, Bulletin 735. Prepared in cooperation with the Soil Conservation Service, U.S. Department of Agriculture. Suloway, L., and M. Hubbel1. 1994. Wetland Resources oflllinois: An Analysis and Atlas. lllinois Natural History Survey Special Publication 15. Champaign, ll... U.S. Department of Agriculture. 1992. The 1992 Census of Agriculture. U.S. Government Printing Office, Washington, DC. Climate ana Trends in Climate Changnon, S.A., Jr. 1984. Climate Fluctuations in llIinois: 1901-1980. llIinois State Water Survey Bulletin 68. Champaign, ll... Changnon, S.A., Jr. 1995. Temporal Fluctuations of Hail in llIinois. llIinois State Water Survey Miscel1aneous Publ.ication 167. Champaign, ll... lllinois Department of Energy and Natural Resources. 1994. The Changing Dlinois Environmeht: Critical Trends. Volume 1: Air Resources. ll..ENRIRE-EA-94/05(l). Springfield, ll... Streamflow Singh, K.P., G.S. Ramamurthy, and I.W. Seo. 1988. 7-Day 10-Year Low Flows of Streams in the Rock, Spoon, La Moine, and Kaskaskia Regions. Dlinois State Water Survey Contract Report 440. 73 Water Use and Availability Bergstrom, R.E., J.W. Foster, L.F: Selkregg, and W.A. Pryor. 1955. Groundwater Possibilities in Northeastern lllinois. lllinois State Geological Survey Circular 198. Champaign, n... Dawes, J.R., and M.L. Terstriep. 1966. Potential Surface Water Reservoirs of North Central lllinois. lllinois State Water Survey Report of Investigation 56. Champaign, n... Dawes, J.R., and M.L. Terstriep. 1967. Potential Surface Water Reservoirs of Northern lllinois. lllinois State Water Survey Report of Investigation 58. nIinois Department of Agriculture. 1995. lllinois Agricultural Statistics: Annual Summary, 1995. Springfield,n... nIinois Department of Energy and Natural Resources. 1994. The Changing lllinois Environment: Critical Trends. Volume 2: Water Resources. n..ENRJRE·EA 94/05(2). Springfield, n... .Ground.Water Quality Gibb, J.P. 1973. Water Quality and Treatment of Domestic Groundwater Supplies. illinois State Water Survey Circular 118. Champaign, n... lllinois Department ofEnergy and Natural Resources. 1994. The Changing lllinois Environment: Critical Trends. Volume 2: Water Resources n..ENRJRE-EA 94/05(2). Springfield, n... 74 ------The Dlinois Depattment of Natural Resources receives federal financial assistance and therefore must comply with federal anti-discrimination laws. In compliance with the Dlinois Human Rights Act, the Dlinois Constitution, Title VI ofthe 1964 Civil Rights Act, Section 504 of the Rehabilitation Act of 1973 as amended, and the U.S. Constitution, the Dlinois Department 'ofNatural Resoul'l:es does not discriminate on the basis of race, color, sex, national origin, age or disability. 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