Demand for water in Illinois is increasing, and water shortages in the Chicago metropolitan area have been projected. There are, however, limits to the availability of clean water at a reasonable cost. Limitsto water availability are imposed by a number of factors including droughts, legal requirements to maintain minimum flows in rivers and streams, water recharge rates, and a decree of the United States Supreme Court limiting withdrawal of water from Lake Michigan. In addition, the specter of regional climate change could pose the greatest threat to Illinois water supplies over the long term: some projections show the possibility of persistent floods, whereas other projections show persistent droughts. Additional sources of water do exist and can be tapped, but the cost of providing clean water increases with the necessity of water treatment, storage, and distribution, and the mitigation of impacts of new withdrawals on existing water supplies. Long lead times also are needed to construct major water projects. Unless the water supplies of Illinois are planned and managed in a comprehensive, regional, and visionary manner--based on the concept of renewable water supply capacity--water shortages could soon occur in some parts of the state. Water supply planning and management should be based on improved understanding and prediction of water supply and demand, and risk assessment. The goal of this plan is to provide a framework for Illinois State Water Survey (ISWS) water supply programs and to document those studies that ISWS, working with others, needs to conduct to provide Illinois with comprehensive technical data and information, models, and training for water supply planning and management. The following are the main tasks described in the plan: Collaborate with other organizations to coordinate and integrate relevant programs, set priorities, plan activities, conduct studies, and seek additional resources. Assemble, archive, digitize, analyze, and synthesize existing data. Determine areas of possible water shortages as a basis for setting priorities. Evaluate the quantity and quality of water resources throughout the state as they relate to water supply. Provide yield estimates for major aquifers and surface waters under variable and changing climatic conditions. Identify critical data gaps and conduct field studies to gather additional data and monitor the state's water resources. Evaluate opportunities for water conservation and reuse. Interpret and apply technical and economic data to assist and train water resource planners and managers. Develop and improve methods and models to evaluate water resources. Develop new quality-assured databases and an Internet-based decision support system to make data and models easily available for application by other agencies, professionals, and the general public. The rate and order of implementation of these studies will depend upon the level and sources of funds and priorities and upon collaborative efforts with other organizations. Existing resources are addressing many of these topics, but resources are limited so progress will be slow. A major infusion of new resources is needed for timely implementation of the studies described.
This report presents extensive information from recently published findings related to the following two critical questions about climate change: andlt;ULandgt; andlt;LIandgt;What will the future climate be like? andlt;LIandgt;What will the effects be, both good and bad? andlt;/LIandgt;andlt;/ULandgt;Chapter 1 introduces the two main chapters of the report that provide insights to the above two critical questions about climate change. Chapter 2 provides examples from a wide spectrum of scientists, scientific organizations, and the media of contradictions and confusion about whether human-induced climate change is predictable over the time scale of a century. It then explains why such climate change is unpredictable in the traditional deterministic sense. It describes the climate system and documents improvements and remaining uncertainties of global climate models relevant to evaluating human-induced climate change on the century time scale. Climate measurements in Illinois since the mid-19th century document major climate swings not evident in a 50- to 100-year record. Illinois is no warmer or wetter today than it has been over the last 150 years, and extreme precipitation events across the country are reported to be no more frequent than they were a century ago. Important conclusions from these data are that i) regional climate trends over the past 50-100 years that are consistent with theoretical expectations of an enhanced greenhouse effect (for example, higher precipitation and more heavy rainfall events in northern mid-latitudes) do not necessarily establish causality; and ii) global warming has not resulted in warming in all parts of the globe. Chapter 3 focuses on the issue of economic impacts of weather and climate in the United States (US). The first section addresses known financial impacts of recent (1950-2000) weather and climate conditions. Descriptions follow of temporal trends of weather and climate extremes and their impacts, causes for on-going increases in economic impacts, and estimates of future financial impacts under a changed climate. The frequency of most types of storms and droughts either has not changed or has decreased during 1940-2000. Yet, losses (1997 dollars) for most storm types have increased over time. Possible causes for increased losses include a shift in climate related to global warming, questionable insurance practices, and aging infrastructure. Study also shows increasing losses due to societal factors, including population growth, more people residing in more weather vulnerable areas, shifts in business-product development that are weather sensitive, and growing wealth. Various studies of weather- and climate-induced economic impacts were used to develop national loss and gain estimates. Projections for the US, depending upon varying assumptions about the future climate (combinations of warmer, wetter, drier, or more storms), show annual climate-related losses ranging from $2 billion to $69 billion, and others estimate annual gains of $30 billion to $40 billion. In all cases, the projected outcomes are small in relation to the expected Gross Domestic Product.
Brochure describing the Illinois State Climatologist, which is located in Champaign, Illinois, at the Illinois State Water Survey (ISWS). The ISWS, a division of the Illinois Department of Natural Resources Office of Scientific Research and Analysis and an affiliated agency of the University of Illinois at Urbana-Champaign, is the primary agency in Illinois for research and information on surface water, groundwater, and the atmosphere.
Levels of Lakes Superior, Michigan-Huron, and Erie were assessed to identify key temporal fluctuations in their averages and extreme values during the 1861-2001 period. Behavior of levels of Lakes Michigan-Huron and Superior since 1861 has included vastly different long-term distributions, differences in amount of variability over time, and differences in occurrence times of their record-high and low levels. Record high or low 15-year periods were present on one or more lakes in 64 years, and record events based on 25-year periods were present in 96 of 141 years, both representative of records during a much longer period than if the record events had occurred simultaneously on all lakes. These lake-level differences reflect significant differences in climate conditions between basins, and principally precipitation over time. There were two eras when levels of all lakes exhibited exceptional variability and extreme high and low levels, 1923-1938 and 1973-2001, reflecting considerable climatic instability over the entire Great Lakes basin.
The objectives of this study were to 1) identify locations along the Fox River wherereductions in the flow rate and/or river water quality are likely to degrade any use of water along the river, 2) assess the prevailing water quality and ecology of a critical reach of the river, e.g., from one dam to the other, and 3) estimate and evaluate water supply and water quality conditions at present and in the future.
The hydraulics of flow was investigated at two reaches in the Kaskaskia River. The discharge varied from 58 to 4000 cubic feet per second and the flow frequency varied from 5 to 88 percent. The head loss varied from 0.96 feet/ mile for high flows to 1.98 feet/mile for low flows. The vertical velocity distribution was found to follow a logarithmic distribution. A theoretical distribution predicted the lateral velocity distribution in the bends reasonably well. In all, 79 isovels were developed for all flow conditions. The average value of the energy coefficient was 1.45 for straight reaches and 1.43 for bends. Similarly, the average value of the momentum coefficient was 1.22 for straight reaches and 1.18 for bends. Manning's roughness coefficient varied from 0.039 to 0.053. During low flows, the river flows through a series of pools and riffles. The median diameter of bed materials varied from 40 millimeters in the riffle to 0.04 millimeters in the pool, whereas the Froude number changed from 0.7 to 0.01. During high flows, the effect of the pool and riffle on the flow condition is minimal or nonexistent.
In the last decade, Illinois has seen many changed attitudes and laws governing the use and withdrawal of ground water. Almost certainly, the next decade will see continued change as the legal structure is adapted to increasing demand for ground water and to the resultant and growing pressures on our ground-water resources. This report summarizes groundwater quantity laws and management programs in Illinois and a number of other states. It compares the present system in Illinois with those in other states and lists recommendations for improvements in Illinois laws.
Driven by the force of gravity, water continually moves between the land surface and the subsurface environments. Our knowledge of this process is limited by the large number of interdependent factors involved. A better understanding of these factors and their effects is needed if we are to effectively manage our water resources in a comprehensive manner.This study addresses the problem by quantifying the groundwater contributionto streamflow over a large range of discharges for 78 watersheds in Illinois.Quantification is the first step toward understanding the dynamics of thiscomplex phenomenon.
An anomalously warm El Nio event developed in the eastern tropical Pacific Ocean during May-August 1997. El Nio events have become recognized as capable of having major effects on atmospheric circulation patterns over North America and elsewhere, leading to predictable outcomes for future seasonal weather conditions. The source of the nation's official long-range predictions, the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC), began issuing forecasts in May 1997 about the event's development and growth to near record proportions. The emerging El Nio was expected to match or exceed the El Nio of 1982-1983, the strongest of this century. Predictions of the future weather conditions expected over the nation, as a result of El Nio's influence on the atmosphere, also were issued by CPC beginning in June 1997. Basically, these and subsequent predictions called for a fall, winter, and early spring in the Midwest that would have above normal temperatures and below normal precipitation. The predictions also called for storms and precipitation to increase in other parts of the nation, particularly in the South and West Coast areas. Media and wide public interest in the evolving record event brought inquiries to the Midwestern Climate Center (MCC) during June 1997. At that time, MCC leadership launched special studies and efforts related to the El Nio event, which included: a climatological reanalysis of past El Nio events and the associated weather conditions in the Midwest, the issuance of outlooks based on these studies, and the collection and analysis of data on the impacts caused by the El Nio-generated weather conditions in the Midwest. This decision was in keeping with past MCC research policy that has focused on assessing extreme Midwestern weather conditions like the 1988 drought (Changnon, 1991a and b), the 1993 flood (Kunkel, 1996; Changnon, 1996), and the 1995 heat wave (Kunkel et al., 1996; Changnon et al., 1996). These studies also focused on identifying and quantifying the impacts of these extreme events. The findings of such activities help the MCC respond rapidly and accurately to numerous regional inquiries for data and information about such extreme events. They also help the MCC prepare for effectively addressing similar events in the future. During the El Nio event, beginning in June 1997 and ending in May 1998, the MCC scientists issued several climate outlooks about future Midwestern conditions. These were basically probabilistic-based statements and focused on the winter of 1997-1998, spring 1998, and summer 1998 outcomes. During the El Nio event, the MCC staff collected and recorded all the relevant weather data for the Midwest. Data defining the impacts of El Nio-generated weather events were collected from August 1997 through August 1998. This report presents information about MCC activities related to El Nio in 1997-1998. It includes three sections: the predictive outlooks issued, a climatic assessment of monthly and seasonal weather conditions during the event, and a description of societal and economic impacts caused in the Midwest. Recommendations are offered in the section "Conclusions and Recommendations" for addressing future El Nio events and the handling of long-range predictions.
Sedimentation detracts from the use of any water-supply lake by reducing lake depth and volume, with a reduction of reserve water-supply capacity and possible burying of intake structures. Sedimentation of a reservoir is a natural process that can be accelerated or slowed by human activities in the watershed. Lake Decatur is located in Macon County, northeast of Decatur, Illinois. The location of the dam is 39 49' 28' north latitude and 88 57' 30' west longitude in Section 22, T.16N., R.2W., Macon County, Illinois. The dam impounds the Sangamon River in the Sangamon River basin. The watershed is a portion of Hydrologic Unit 07130006 as defined by the U.S. Geological Survey. The lake was constructed in 1922 with a spillway level of 610 feet above mean sea level (feet-msl). In 1956, a set of hydraulic gates was installed on the original spillway to allow variable lake levels from 610 feet-msl to 615 feet-msl. The portions of the lake surveyed for the present study were the Big and Sand Creek basins. These basins are the two major tributary stream basins formed to the south (Sand Creek) and east (Big Creek) of the main body of the lake. They receive the flow of Sand, Big, and Long Creeks. Lake Decatur has been surveyed to document sedimentation conditions nine times since 1930. Five of these survey efforts (1936, 1946, 1956, 1966, and 1983) were sufficiently detailed to be termed full lake sedimentation surveys. The survey discussed in detail in this report is not a full lake sedimentation survey. However, additional work included in the present study could be combined with the 2000 survey of Basin 6 of Lake Decatur to provide a complete baseline survey for future reference. Sedimentation has reduced Big Creek basin capacity from 2,754 acre-feet (ac-ft) in 1922 to 1,512 ac-ft in 2001. The 2001 basin capacity was 54.9 percent of the 1922 potential basin capacity. For water-supply purposes, these volumes convert to capacities of 897 million gallons in 1922 and 493 million gallons in 2001. Sedimentation rate analyses indicate a decline in annual sediment deposition rates from 28 ac-ft (1922-1946) to 9.9 ac-ft annually (1983-2001). The long-term average annual deposition rate was 15.7 ac-ft (1922-2001). Sedimentation has reduced the Sand Creek basin capacity from 610 acre-feet (ac-ft) in 1922 to 246 ac-ft in 2001. The 2001 basin capacity was 40.3 percent of the 1922 potential basin capacity. For water-supply purposes, these volumes convert to capacities of 199 million gallons in 1922 and 80 million gallons in 2001. Sedimentation rate analyses indicate a decline in annual sediment deposition rates from 8.4 ac-ft (1922-1946) to 2.3 ac-ft annually (1983-2001). The long-term average annual deposition rate was 4.6 ac-ft (1922-2001).