This document provides pertinent information on the spatial distribution characteristics of extremely heavy rainstorm events in Illinois and the Midwest. Relations were developed for those storms in which maximum rainfall at the center equaled or exceeded the point maximum experienced on the average of once in 100 years or longer. The study was limited to this group of storms because of existing needs for information on these extreme storm events in the design and operation of water control structures in small basins. It is recommended for use in conjunction with Illinois State Water Survey Bulletin 70, Bulletin 71 (Midwestern Climate Center Research Report 92-03), and Water Survey Circular 173 for runoff computations related to the design and operation of runoff control structures in small basins subject to extreme rainfall events. Area-depth relations were derived from information obtained through operation of several dense raingage networks, detailed field surveys and analyses of severe rainstorms in Illinois, analyses of heavy rainstorms in a six-basin hydroclimatic study, and exceptional storms recorded by the climate network of the National Weather Service in Illinois. Using data and information from these sources, curves defining spatial distributions for storms of various areal extent were derived. Results are presented in a form readily adaptable for use by hydrologists or other interested users.
This report documents the structure and the use of an improved version of the Windows-based interface of the unsteady flow model, UNET. This interface was developed by the Illinois State Water Survey for the Office of Water Resources, Illinois Department of Natural Resources. The current version of the interface program can download historic, real-time, and forecasted stage and flow data from U.S. Geological Survey, U.S. Army Corps of Engineers, and National Weather Service Web sites interactively. These data can be used to update an existing Data Storage System (DSS) database or to create new ones. The interface allows the user to create or update gaging station information in a Microsoft Access database. The user can create project files to run the UNET model for historic, design, real-time, and forecasted flood events. The graphing function allows plotting of single and multiple hydrographs, or stage profiles of a single reach and multiple reaches. The utility tools include screen captures, document editing, and DSS file editing. This interface program uses the original UNET generic geometry and boundary condition files to maintain the same level of accuracy as the UNET model, but it also allows the user to change some of the parameters, such as, the simulation time interval, time windows, and numerical Corant number, and etc., in the BC file. Real-time simulation of a flood event simulates flood stage profiles using real-time stage and flow data downloaded from related Web sites. Locations and magnitudes of levee overtopping will be displayed for the lower Illinois River should these occur. The interface program lets the user modify parameters to simulate simple levee failure or two types of complicated embankment failures, overtopping and piping. Simulations also can be performed using the modified levee information, such as breaches or revised crest elevations. The change of water surface elevation induced by modifying levees can be compared with another simulation graphically and also in table format. Stage profiles from all simulations can be plotted together with levee heights on both sides of the channel along the Lower Illinois River to visually show the impacts of particular floods.
A field-scale project in Mason County, Illinois, was performed to monitor the movement of nitrate in ground water beneath an irrigated field. Chemical tracers were used to assess the migration of solutes both laterally and vertically under the influence of an irrigation well and to determine the amount of recycling at a site due to irrigation pumpage and the amount of off-site transport of nitrate due to regional ground-water flow. Water samples from the sand aquifer at the site reveal considerable spatial and temporal heterogeneity in aqueous chemistry. Recharge is rapid in this system, and it is probable that the water chemistry of the recharge water also is variable spatially and temporally; it is especially influenced by agricultural practices. Nitrate (NO3-) concentrations are elevated in a zone between approximately 15 and 30 feet (ft) beneath the surface, although this zone was not persistent laterally or with time. The maximum nitrate concentrations in this zone were slightly greater than 20 milligrams per liter (mg/L) as nitrogen, well above the drinking water standard of 10 mg/L. Nitrate was generally absent below 30 ft in the aquifer, probably due to denitrification reactions. The tritium data suggest that vertical movement of solutes in the aquifer is rapid, and that there has been enough time to transport solutes from the surface or soil zone to depths in excess of 100 ft. Because drinking-water wells generally are screened well below the zone of elevated nitrate concentrations in this area, it appears that fertilizer applications do not have a negative effect on drinking-water quality for most homeowners. From the results of tracer tests, the effects of irrigation pumping on solute transport are measurable but not substantial. Tracer movement both horizontally and vertically was slight under pumping conditions, less than 10 ft horizontally and between 1 and 2 ft vertically about 100 ft from the irrigation well after three days of pumping. The vast majority of nitrate applied in this area is not being recycled through the irrigation wells.
This investigation is the first of three phases of a ground-water management study. In this report, effects of irrigation and drought on the ground-water resources of Illinois are examined. Irrigation water use for five soil types is estimated from a monthly water budget model on the basis of precipitation and temperature data from the last 30 years at selected weather stations across Illinois. Moisture deficits are computed for each soil type on the basis of the water requirements of a corn crop. It is assumed that irrigation is used to make up the moisture deficit in those places where irrigation systems already exist. Irrigation water use from each township with irrigated acreage is added to municipal and industrial ground-water use data and then compared to aquifer potential yields. The spatial analysis is accomplished with a statewide geographic information system. An important distinction is made between the seasonal effects of irrigation water use and the annual or long-term effects. The model is tested for its sensitivity to weather variation; seasonal water deficits are calculated by using data from extreme growing seasons and extended drought periods. The effect of increasing the amount of irrigated land by 50 percent is also considered for normal weather conditions and droughts. The effect of variable irrigation demand on ground-water resources is expressed as the ratio of ground-water use to ground-water potential yield for each township. This is done to highlight regions most susceptible to ground-water stress because of drought or increased irrigation by showing where use could exceed yield. The sensitivity of the results is not tested for variations in spatial aggregation. This will be one of the primary tasks in subsequent study phases. Results show that irrigation is a substantial seasonal consumptive ground-water use in Illinois, with the potential for growth. However, present effects appear to be localized and highly dependent on weather conditions. Some potential for seasonal or temporary overpumpage may exist in the heavily irrigated areas during years with below-normal precipitation or during extended droughts. The aquifers being used for irrigation appear to have the ability to recover from present irrigation demands without suffering significant depletion, implying that the annual effect of irrigation is currently relatively minimal. The exception to this may be during extended drought periods, especially if widespread expansion of irrigation practices also occurs in the state. A 50 percent expansion of irrigation would appear to have surprisingly little additional impact on ground-water resources under most climatic conditions. That degree of growth around currently irrigated land would result in expanded irrigation areas still within reach of the productive, high-yielding aquifers already being pumped for irrigation. A much larger degree of irrigation expansion into areas with heavier-textured soils is possible in Illinois. The availability of ground-water would be a major limiting factor in the speed and direction of that expansion. That kind of massive irrigation expansion is not considered in this report; however, its effects on the state's ground water are assumed to be considerable and will be addressed in subsequent study phases. The Chicago metropolitan area stands out as a major region of overpumpage, but not because of irrigation. Variable irrigation pumpage does appear to consistently affect several other regions, most notably parts of Mason, Kankakee, Tazewell, Lee and Whiteside Counties. The degree to which these counties are affected by irrigation depends largely on weather conditions. For all these counties, with the possible exception of Kankakee, surficial sand and gravel aquifers are the most susceptible to stress from drought and irrigation water use. Shallow bedrock aquifers may also be impacted by irrigation in parts of Kankakee County. The impact of an extended drought is likely to be more widespread and inconsistent because of the multiple effects of increased water use for irrigation and other demands, and reduced ground-water storage.
This report is the second of a series of three reports being prepared for the work done on the Kankakee River based on a Conservation 2000 Grant from the Illinois Department of Natural Resources. The present report focuses on the bank erosion mapping of the main stem of the Kankakee River from Route 30 Bridge in Indiana to the mouth of the Kankakee River with the Illinois River near Wilmington. A total of 111.8 river miles were mapped during a boat trip November 19-December 1, 1998. The relative magnitude of erosion was based on a visual assessment of the river banks during a boat trip along the main stem of the river. No actual measurements were taken. However, the extent of erosion was noted on 7.5-minute quadrangle maps based on visual observations. A series of 27 maps has been developed in which bank erosion identified on both sides of the river ranged form minor to high erosion. This analysis has shown the 10.4 river bank miles had severe erosion, 39.4 bank miles had moderate erosion, 70.8 bank miles had minor erosion, 46.3 bank miles were stable, 46.7 river bank miles were artificially protected, and data on 10.0 bank miles could not be collected because snags, islands, etc. made the banks inaccessible. This is a first attempt to map existing bank erosion conditions of the main stem of the Kankakee River.
Riparian forests have been proposed by the Technical Advisory Subcommittee of the Upper Embarras River Basin Commission in its alternatives for mitigating flood damages in the Village of Villa Grove and nearby farmlands. In order to evaluate potential reduction in flood stages in Villa Grove, methods for accounting for flow resistances induced by the riparian forests are needed in the hydraulic model for the Upper Embarras River. This project has been designed to better apply the available knowledge in practical field applications, particularly, how to evaluate the vegetal roughness in terms of Manning's andlt;EMandgt;nandlt;/EMandgt; coefficient for specified planting scenarios. Approaches presented in this report are literature review on Manning's roughness with emphasis on vegetative roughness, and evaluation and selection of methods for computing vegetative roughness due to riparian forests. The Petryk and Bosmajian (1975) method was selected for evaluating Manning's andlt;EMandgt;nandlt;/EMandgt; for mature trees because parameters could be reasonably obtained with available general field information. Using this approach, effects of riparian forest on floods were evaluated with the scenarios that the two-year floodplain has two densities of trees. The study reach was the channel between Villa Grove and Camargo. Also investigated were the options of having uniform tree density for the whole reach or half of the reach. An interface has been developed for implementing the computed andlt;EMandgt;nandlt;/EMandgt; values to a HEC-RAS hydraulic model, and capacity curves were developed to illustrate the effects on flood conveyance among these scenarios. The capacity curves thoroughly included possible boundary conditions and were presented in simple nomographs that relate discharge and downstream elevations to a specified flood elevation in Villa Grove. Therefore it was easier to evaluate the resulting effects of different alternatives.
Realizing the importance of Peoria Lake and the seriousness of the sedimentation problem of the lake, the Illinois State Water Survey initiatedthe Peoria Lake Sediment Investigation under the sponsorship of the U.S. ArmyCorps of Engineers, Rock Island District.The main objectives of the study were to:- Determine the sedimentation rate of the lake- Identify the sources of sediment to the lake and their relativequantities- Develop a sediment budget- Investigate the quality of the sediment in the lake- Investigate a range of alternative solutions to the sedimentationproblem of the lake and make recommendationsThis project will address alternative solutions to the problem of sedimentation in Peoria Lake.
The First Sino - U.S. Joint Workshop on Sediment was organized with strong support from both the United States and China, with the intention to strengthen information exchange and cooperation on research on emerging hydro-environmental problems. The Natural Science Foundation of China has established a national key research project, Study on Mechanisms of River Sedimentation, Disasters, and Control Strategies in China, and is interested in establishing a bilateral cooperation program with the United States on sediment transport and sediment-induced disasters. A joint workshop was considered to be an effective approach for scientists and engineers from both countries to exchange knowledge and experience, to explore research and educational needs, and to initiate future collaborations. In a three-day meeting in Beijing, China, followed by a five-day field study in the Loess Plateau along the middle reach of the Yellow River, the participants exchanged information on sediment-related topics and identified opportunities for future research and cooperation. A major emphasis of the workshop was to promote direct discussions, and the workshop sessions were structured accordingly. The format worked very well and resulted in ample exchange of experiences and needs for future studies. This report presents information from the workshop and summaries of discussions from the meeting in Beijing.
A large undeveloped ground-water reservoir underlies an area along the Illinois and Sangamon Rivers in west-central Illinois. The area is called the Havana region in this report.This report is based on data collected during the investigation and additional data on file at the Illinois State Water Survey and the Illinois State Geological Survey and in published reports. It presents geologic and hydrologic information, the geologic history of the area, present hydrologic conditions, and effects of possible future development on the ground-water resources of the region. Special emphasis is placed on the extensive unconsolidated sand and gravel deposits, which are the principal aquifers in the region, and their potential yield is evaluated. The geology and hydrology of the bedrock formations are discussed only briefly as these formations contain limited quantities of ground water, and it is of relatively poor quality. Data on water levels, pumpage, well construction features, water temperature, mineral quality of water, well-production and aquifer tests, and other hydrologic information were collected by the State Water Survey. Well logs, drilling samples, geophysical logs, and other geologic information were collected by the State Geological Survey.
Recharge conditions in several areas of northeastern Illinois are described, and recharge rates for several aquifers in central and southern Illinois are given. Recharge rates to deeply buried bedrock and sand-and-gravel aquifers vary from 1300 to 500,000 gallons per day per square mile (gpd/sq mi). The lowest rate is for an area where the Cambrian-Ordovician Aquifer is overlain by the Maquoketa Formation consisting mostly of shale; the highest rate is for an area where a sand-and-gravel aquifer is overlain by permeable coarse-grained deposits. Groundwater recharge generally is at a maximum during wet spring months; in many years there is little recharge during the five-month period July through November. The theoretical aspects of recharge from precipitation are discussed; recharge rates vary with the coefficient of vertical permeability, the vertical head loss associated with recharge, and the saturated thickness of deposits through which vertical leakage of water occurs. Recharge rates are not constant but vary in space and time. A summary of coefficients of vertical permeability and leakage of deposits overlying aquifers within the state is presented. Coefficients of vertical permeability of glacial deposits range from 1.60 to 0.01 gallons per day per square foot (gpd/sq ft). The average coefficient of vertical permeability of the Maquoketa Formation is 0.00005 gpd/sq ft. Coefficients of leakage of glacial deposits and bedrock confining beds range from 2.3 x 10-1 to 2.5 x 10-7. Annual ground-water runoff from 109 drainage basins scattered throughout Illinois is estimated with streamflow hydrograph separation methods and flow-duration curves. The relations between groundwater runoffs during years of near, below, and above normal precipitation and basin characteristics such as geologic environment, topography, and land use were determined by statistical analysis. Groundwater runoff is greatest from glaciated and unglaciated basins having considerable surface sand and gravel and underlain by permeable bedrock. Groundwater runoff is least from glaciated basins with surface lakebed sediments and underlain by impermeable bedrock. Groundwater runoff during a year of near normal precipitation ranges from 0.06 to 0.43 cubic feet per second per square mile (cfs/sq mi). Groundwater runoff is at a maximum during spring and early summer months, and is least in late summer and fall months. Annual groundwater runoff depends upon antecedent moisture conditions as well as the amount and distribution of annual precipitation. Because many aquifers in Illinois are deeply buried, not all groundwater runoff can be diverted into cones of depression because there is some lateral as well as vertical movement of water in surface deposits. Data on groundwater runoff can be useful in estimating recharge to aquifers and in evaluating the potential yield of groundwater reservoirs. However, studies indicate that no simple relation exists between groundwater runoff and the potential or practical sustained yields of aquifers.