In the East St. Louis vicinity, the Illinois Department of Transportation Division of Highways (IDOT) owns 56 high-capacity wells that are used to maintain the elevation of the groundwater table below the highway surface in areas in which the highways were constructed below the original land surface. The dewatering systems are located at five sites in the alluvial valley of the Mississippi River in an area known as the American Bottoms. The alluvial deposits at the dewatering sites are about 90 to 115 feet thick and consist of fine sand, silt, and clay in the upper 10 to 30 feet, underlain by about 70 to 100 feet of medium to coarse sand. The condition and efficiency of a number of the dewatering wells became suspect in 1982 on the basis of data collected and reviewed by IDOT staff. Since 1983, IDOT and the Illinois State Water Survey have conducted a cooperative investigation to more adequately assess the operation and condition of the wells, to attempt to understand the probable causes of well deterioration, and to evaluate rehabilitation procedures used on the wells. Work scheduled for FY 00 (Phase 17) included conducting 18 condition-assessment and posttreatment step tests, monitoring of the chemical treatment of 11 wells, and observing and documenting the construction of 2 new (replacement) dewatering wells. Of the 18 step tests conducted, 11 were post-chemical-treatment step tests, 5 were routine condition assessment step tests on existing wells, and 2 were condition assessments on newly constructed wells. The results of the five condition assessment step tests indicated specific capacities ranging from 25.1 to 65.2 gallons per minute per foot (gpm/ft), corresponding to very poor to fair well conditions, respectively. It was recommended that all five wells be chemically treated in FY01. Posttreatment step tests were used to help document the rehabilitation of 11 dewatering wells during FY 00 (Phase 17): I-70 Wells 2A and 8A; 25th Street Wells 2, 3, 4, 5, 7, 8, and 9; and Missouri Avenue Wells 2 and 3. Chemical treatments used to restore the capacity of these seven wells were moderately successful. There was a wide range of improvement in specific capacity per well, ranging from 2 percent to 503 percent improvement, and averaging 124 percent based on specific-capacity data from pre- and posttreatment step tests. A sand pumpage investigation, which was conducted during 15 of the 18 step tests during FY 00, revealed that 25th Street Wells 2, 3, and 4 were pumping sand. These conditions may pose a threat to the long-term operation of these wells, especially 25th Street Well 4. Smaller amounts of sand were found following the step test for 25th Street Wells 2 and 3.
Cambrian and Ordovician strata provide much of the groundwater supplyfor approximately 250 municipalities and 150 industries in the northern halfof Illinois. This report represents the cooperative effort of the IllinoisState Water Survey, Illinois State Geological Survey, and U.S. GeologicalSurvey to provide a current hydrogeologic evaluation of this water resource.
The Illinois Streamflow Gaging Network has been operated by the U.S. Geological Survey (USGS) since the early 1900s. From its inception, the operation of the network has been maintained through a cooperative partnership between the USGS and state and federal agencies. Hydrologic information provided by the network is vital for the general management of Illinois' water resources. Streamflow data are continually used for forecasting floods and droughts; assessing the biological and chemical health of our streams; operating reservoirs, water supply facilities, wastewater treatment facilities, and hydroelectric plants; assessing and predicting the long-term impacts of climate and land-use trends on our streams; and numerous other important uses. The purpose of this study was to conduct a comprehensive evaluation of the use of Illinois streamflow data, with the goal that this information and analysis will be used by the network's cooperating agencies and others for current and future decisions related to funding and content of the network. Evaluations such as this have been conducted in the past, and should continue to be conducted periodically to assess whether the network meets the data needs of users in an effective manner, to assess emerging needs, and to anticipate needed programmatic changes to the network. This report identifies several emerging applications for which more and additional types of stream data likely will be needed, including applications related to stream and watershed restoration and water quality load assessment. However, in general, it is not possible to anticipate many of the future needs of the streamflow gaging program. More often than not, emerging issues will need to use streamflow data far before there is sufficient time to collect data for that specific use. The only way to have adequate data when these needs arise is to maintain a base network at locations that are representative of the streams of Illinois, such that these long-term data are available to meet a broad range of potential needs. This base network of gaging stations also is needed to provide general streamflow information for ungaged streams throughout Illinois. There are thousands of streams in Illinois, whereas the network currently includes roughly 160 continuous-streamflow gages on fewer than 110 of these streams. For other streams, flow characteristics must be estimated from the available gaging records using regional hydrologic principles. Various methods are available to evaluate the effectiveness of specific gaging records for use in this regional transfer of information. This report includes several descriptive measures of the regional value of gage information and also summarizes a numerical evaluation based on information transfer theory. No single approach can effectively describe the broad range of considerations needed to evaluate the regional value of gages. However, it is clear that applications in regional hydrology will need additional data beyond those which are currently supported by the network. Specifically, the base network is noticeably lacking data from small watersheds in rural Illinois. In addition, several hydrologic regions in Illinois have a limited number of gages for use in regional analysis. Two questionnaires were developed to ascertain the importance and uses of the data from the streamflow gaging network. The first questionnaire was distributed to all agencies that provide cooperative funding to the network. The second questionnaire was developed on an Internet Web site to be accessed and filled out by all interested users of Illinois streamflow data. In both questionnaires, the respondents were asked to identify: 1) the types of data that they most frequently use and/or are most critical for their needs; 2) categories of data applications and their relative importance; and 3) the importance of specific gages for their applications. The report provides a ranking of the relative importance of individual gages based on the responses from the questionnaires. The users indicate that river forecasting/flood warning is the overall most important category of application of streamflow data, followed by long-term flow statistics for analyzing hydrologic trends and determining human impacts to streams. However, the majority of users are more likely to use streamflow data for individual project needs such as those related to hydrologic-hydraulic modeling and design, and biological and conservation assessment. Analysis of gaging records indicates that streamflow conditions are not stationary, and vary not only from year to year but also from decade to decade as influenced by climate variability and other factors. More than half of the long-term flow records in rural areas show statistically significant increases in average and low-flow conditions that appear to occur as a result of climate variability. Statewide, over the past 25 years, there has also been an average increase of 18 percent in the estimates of the 100-year flood peak discharge as represented by long-term records. With the decline in the number of crest-stage peak-flow gages and small watershed gages, many of the records available for certain types of hydrologic analysis are older, discontinued gaging records that may not accurately represent the expected present-day, long-term hydrologic conditions. Shorter gaging records, regardless of period of record, also may not fully represent the expected long-term conditions. There is a need for analytical techniques to assess inherent differences in streamflow records and characteristics such as flood frequency that are caused by climatic variability and other factors. The network appears to be meeting most traditional current-use needs. However, there is a need to reinforce the base network, specifically regarding data for relatively small rural watersheds that are needed to address various emerging issues, long-term regional assessment, and peak flood estimation. The size of the overall network would have to be increased an additional 15-20 percent to more effectively address data needs related to small to medium-sized rural watersheds. Also, there is a growing need for new types of stream data to address specific biological and conservation issues such as stream and watershed restoration. This report only addresses streamgaging issues related to flow quantity, and thus there are no conclusions or recommendations related to water quality, precipitation, or other types of hydrologic data. Funding for the Illinois Streamflow Gaging Network is subject to uncertainties, and this is especially the case regarding potential growth or changes to the network. The National Streamflow Information Program (NSIP), initiated by the USGS in 1999, proposed that the USGS eventually would assume the costs of gages that directly meet specific federal interests. However, it is uncertain whether this or other initiatives from traditional funding sources will produce a prominent change in the size and character of the network. More likely, gaging needs for emerging issues will need to be funded from new sources currently not participating in the network. By its nature, it is essential that the base network be funded mainly through state or federal agencies with a long-term commitment to the streamflow gaging program.
Episodic controls on sources of ozone precursor gases have been suggested as an alternative to continuous controls as a strategy for reducing ozone concentrations to meet current air quality standards. To show the feasibility of episodic controls to meet ozone air quality standards, it is first necessary to show that it is feasible to forecast surface ozone concentrations with sufficient accuracy and sufficient lead time that episodic controls can be instituted. This study examined the feasibility of a statistical forecast of surface ozone concentrations in the Chicago area (Lake, Cook, and DuPage Counties), based on current concentrations and current and expected weather conditions. Forecast methods were developed using historical data on surface ozone concentrations and meteorological variables measured from 1990-1995. Overall, the study included: andlt;ULandgt; andlt;LIandgt;An extensive literature review and summary. andlt;LIandgt;Documentation of forecast methods used to call Ozone Action Days. andlt;LIandgt;Analysis of Ozone Action Days called in 1995-1997. andlt;LIandgt;Creation of air quality and meteorological databases. andlt;LIandgt;Examination of bivariate relationships between ozone and meteorological variables, including back trajectories on days with high ozone concentrations. andlt;LIandgt;Development of four forecasting approaches involving regression equations and two methods of adjusting or enhancing the results of the regression equations. andlt;LIandgt;Analyses of forecasts based on the four approaches.andlt;/LIandgt;andlt;/ULandgt;
A dense raingage network has operated in Cook County since the fall of 1989, to provide accurate precipitation for use in simulating runoff for Lake Michigan diversion accounting. This report describes the network design, the operations and maintenance procedures, the data reduction and quality control methodology, a comparison of rainfall amounts obtained via analog chart and data logger, and an analysis of precipitation for Water Year 2002 (October 2001 - September 2002). The data analyses include 1) monthly and Water Year 2002 amounts at all sites, 2) Water Year 2002 amounts in comparison to patterns from network Water Years 1990-2001, and 3) the 13-year network precipitation average for Water Years 1990-2002. Also included are raingage site descriptions, instructions for raingage technicians, documentation of raingage maintenance, and documentation of high storm totals.
A dense raingage network has operated in Cook County since the fall of 1989, to provide accurate precipitation for use in simulating runoff for purposes of Lake Michigan diversion accounting. This report describes the network design, the operations and maintenance procedures, the data reduction methodology, and an analysis of precipitation for Water Year 2000 (October 1999 through September 2000). The data analyses include 1) monthly and Water Year 2000 amounts at all sites, 2) Water Year 2000 amounts in comparison to patterns from network Water Years 1990-1999, and 3) the 11-year network precipitation average for Water Years 1990-2000. Also included are raingage site descriptions, instructions for raingage technicians, documentation of raingage maintenance, and documentation of high storm totals.
This document provides the best available in formation on the time-distribution characteristics of heavy rainstorms at a point and on small basins in Illinois and the Midwest. It is recommended for use in conjunction with Illinois State Water Survey Bulletin 70 and Circular 172 for runoff computations related to the design and operation of runoff control structures. It is also useful for post-storm assessment of individual storm events in weather modification operations. Information is presented in the form of families of curves derived for groups of storms categorized according to whether the greatest percentage of total storm rainfall occurred in the first, second, third, or fourth quarter of the storm period. The time distributions are expressed as cumulative percentages of storm rainfall and storm duration to enable comparisons between storms. The individual curves for each storm type provide estimates of the time-distribution characteristics at probability levels ranging from 10% to 90% of the total storm occurrences. Explanations are provided of how to use the results in design problems.
This circular presents basic information on water quality and treatment of domestic and farm groundwater supplies. It describes tests and practices that assure a safe sanitary water quality, and discusses in detail the common minerals and natural gases that are of concern to home water supplies in Illinois. It describes water treatment procedures and equipment for disinfection, iron removal, softening, methane and hydrogen sulfide gas removal, and their costs.
An analysis of long-term records of corn yields, water resource conditions, and seasonal weather conditions in Illinois found major temporal shifts and important spatial variations in the types of seasonal weather conditions that have positive and negative impacts on yields and water conditions. Nineteen different types of corn-weather seasons (May-August) occurred during 1901-1997, of which nine types accounted for most of the high corn yields (highest 20 of the 97 values) and eight types produced most low yields (lowest 20 values). An assessment of the years with either high or low yields revealed three findings about the distributions of the corn-weather seasons creating these extremes: 1) some types were uniformly distributed throughout the century; 2) others were unevenly distributed over time, some occurring only in the century's early decades and others only in the last few decades; and 3) certain types varied greatly regionally. Yield responses to certain seasonal types varied over time. The findings helped establish that changes in farming practices, corn varieties, and agricultural technology all affect how a given type of growing season affects corn yields. Sizable regional differences in yield outcomes from a given set of weather conditions, a result of varying soil and climate differences across Illinois, further revealed how impacts of similar seasonal weather conditions can vary spatially. These two conclusions revealed the importance of using weather effects in defining seasonal extremes. In general, the statewide results showed that the types of seasons creating high yields predominated during 1901-1910 and 1961-1997, and most seasons creating low yields were concentrated in 1911-1920, 1931-1940, and 1951-1960. Major seasonal weather effects on Illinois' water resources (surface water supplies, ground-water supplies, and water quality) were found to occur in the spring and summer seasons. Two conditions caused these effects in each season: either above normal temperatures and below normal precipitation, or above normal temperatures and precipitation. Spring impacts on water resources were typically mixed, some negative and some positive, whereas impacts from summer season extremes had largely negative impacts on water supplies and water quality. More impacts, positive and negative, occurred in southern Illinois than elsewhere, and most of the seasons having negative impacts on water resources occurred in Illinois during 1911-1960. Comparison of the 1901-1997 temporal distributions of yield extremes (high and low) and the negative summer water resource impacts with the temporal distributions of cyclone passages and the incidence of El Nio Southern Oscillation conditions that affect spring and summer weather conditions revealed a generally good relationship. Periods with many seasons creating numerous negative impacts on corn yields and water resources occurred in several decades (1911-1920, 1931-1940, and 1951-1960) when the number of cyclones was low and most incidences of La Nia conditions that create warm temperatures and negative impacts prevailed. Conversely, when seasonal weather conditions were generally beneficial (1901-1910, 1961-1970, and 1981-1997), Illinois had relatively large numbers of cyclone passages and most El Nio-related cool and wet summers occurred. Consideration needs to be given to the shifting temporal responses to various kinds of seasonal weather conditions during the 20th century to determine how future climatic conditions may affect Illinois' agriculture and water resources. Furthermore, some influential seasonal weather types appeared sporadically, some only during the early decades of the century and others only in the latter decades. Thus, data from the past 97 years reveal that efforts to project impacts of future climate conditions on agriculture and water resources may be difficult and subject to considerable error.