IGA Fall 1996 Abstracts

Starved Rock Lodge, Ottawa, Illinois

Groundwater Remediation Using In-Situ Air Sparging­Laboratory Investigation of System Variables
Jeffrey A. Adams and Krishna R. Reddy, University of Illinois at Chicago, Chicago, IL

Characterization of Glacial Deposits at the Neutrino Fixed Target Beamline, Fermilab
Paul Kesich, Fermilab, Batavia, IL

Estimating Evapotranspiration in a Groundwater Fed Wetland in Southwestern Wisconsin­Traditional and Geochemical Approaches
R. Brandon Lott, University of Wisconsin, Madison, WI
Randy J. Hunt and Ken W. Potter, U.S. Geological Survey, Madison, WI

Hydrogeological Criteria for a Low-level Radioactive Waste Site in Illinois­Update on the LLRW Task Group's Proposal
Dr. Colin Booth, Northern Illinois University, DeKalb, IL and
Member of the Illinois Low-Level Radioactive Waste Task Group

Surface Barriers to Limit Water Infiltration into Underlying Waste or Contaminated Soil
David E. Daniel, University of Illinois, Urbana, IL

Sowing the Seeds, Public Awareness of the Role Geology Plays in Watershed Ecosystem Development
Myrna Killey and Daniel Barnstable, Illinois State Geological Survey, Champaign, IL

Determination of Capture Zones and Recharge Areas of Pumping Wells in Laterally Homogeneous, Stratified Materials­A Generic Multi-Dimensional Model Simulation
Shannon Fulton, Lewis, Yockey, and Brown, Bloomington, IL
Larry Barrows, Illinois State University, Normal, IL

GIS Application in Hydrogeology
Rey de Castro, GIS Solutions, Inc., Springfield, IL

Finding Water on the Web­The Growing Influence of the Internet on the Water Resource Community
Faye Anderson, Southern Illinois University, Carbondale, IL

Methods for Characterizing the Hydrogeology of an Underground Mine for Disposal of coal combustion Residues
Steven Esling and Timothy McDonald, Southern Illinois University, Carbondale, IL
Edward Mehnert, Illinois State Geological Survey, Champaign, IL

RBCA: Design/Development/Impact
Gerald Phillips, Region 5, U.S. Environmental Protection Agency, Chicago, IL

Detailed Geologic Mapping of Illinois in Three Dimensions for Aquifer Characterization and Groundwater Protection
Dr. William W. Shilts, Chief, Illinois State Geological Survey, Champaign, IL

The Illinois Groundwater Consortium­Research on the Effects of Agricultural Chemicals and the Floods of 1993 and 1995
Dr. Victoria Molfese, Southern Illinois University, Carbondale, IL
 

An Educational and Cost-Effective Program for the Assessment of Nitrate and Coliform Bacteria in Rural Domestic Wells in Illinois
Joseph Karny, Illinois State Water Survey, Champaign, IL

The Effect of Septic Systems on Groundwater Quality in the Prairie Aquigroup and Alexandrian-Maquoketa Aquifer, Campton Township, Kane County, Illinois
Kurt Kraske, Northern Illinois University, DeKalb, IL; now with Harza Environmental Services

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Groundwater Remediation Using In-Situ Air Sparging­Laboratory Investigation of System Variables

Jeffrey A. Adams and Krishna R. Reddy, University of Illinois at Chicago, Chicago, IL





In-situ air sparging is a relatively new technique that has proven to be both an effective and a cost efficient method for remediating groundwater VOC contamination. Unfortunately, the current design of field air sparging systems must be based solely on pilot tests and past experience because very little laboratory investigation has been performed to study critical parameters and vital issues involving air sparging such as the system control variables and the major contaminant removal mechanisms. In addition, a rational design basis which incorporates experimental study with site-specific testing and past field experience, does not currently exist. As a result, the present implementation of field systems often requires extensive modifications in design during the remediation program in order to improve air sparging performance, leading to larger expenditures of both time and money.
 

To address this situation, a comprehensive research program has been undertaken at the University of Illinois at Chicago (UIC). The objectives of this research program are: (1) to investigate the effects of soil heterogeneities, namely particle size, gradation, layers and lenses of differing permeabilities, and groundwater flow on air sparging; (2) to determine how the contaminant form and location in a soil affect its rate of removal during air sparging; (3) to evaluate how system operation parameters, namely gas type, injection flow rate, and type of injection method affect air sparging; (4) to assess the performance of air sparging systems which have been implemented in different field settings; and (5) to develop specific design guidelines for the design and optimization of air sparging systems. Controlled one-dimensional and two-dimensional laboratory simulation tests are being performed to achieve several of these objectives.
 

This presentation will discuss the effect of grain size and grain size distribution of soils as well as the mode of air injection on the contaminant removal rates during air sparging. Air sparging column experiments were conducted on three uniform or poorly graded soils (coarse sand, medium sand, and fine sand), and a well-graded soil. For this study, the soil samples were saturated with a known concentration of benzene solution. Clean air was then injected into the soil column under pre-selected pressure and flow rate conditions. During testing, benzene concentration profiles were measured in the soil at different time intervals by sampling pore water from sampling ports and injecting into a gas chromatography (GC). The inflow and outflow air pressures, flow rates, and benzene concentrations were also measured during testing.
 

In addition, the use of pulsed air injection vs. continuous air injection was investigated. Using samples of coarse sand and fine sand, two pulsed flow regimes (one hour on, one hour off; three hours on, three hours off) were used to determine if pulsed air flow offers any operational or overall remediation time reduction when compared to continuous air injection.
 
 



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Characterization of Glacial Deposits at the Neutrino Fixed Target Beamline, Fermilab

Paul Kesich, Fermilab, Batavia, IL





Fermilab is a Department of Energy (DOE) high energy physics research laboratory operated by Universities Research Association, Inc. (URA). High energy protons which interact with stationary targets located within experiments at the fixed target beamlines initiate cascades of secondary hadrons. Hadronic showers produced from interactions of the incident beam can be composed of many different subatomic particles. These subatomic particles, if unshielded, can interact with soil located around these locations causing the production of radionuclides. Tritium (3H) has been shown to be the radionuclide of most concern for migration through the subsurface.
 

The Neutrino Area Target Tube was used extensively for targeting protons from early in the lab's history until 1982 when targeting was moved further upstream into the N01 enclosure where shielding of steel and concrete were used more extensively. Recent monitoring of groundwater within the upper glacial deposits in the vicinity of this target has shown levels of 3H increasing in one monitoring well.
 

The scope of the site investigation conducted during the summer of 1996 was to characterize the glacial and upper dolomite's geology and hydrogeology at two locations along the Neutrino Beamline, NS1 and NS2. The geologic characterization at each site included the drilling and sampling of three deep borings into bedrock. Rotosonic drilling methods were used to obtain a continuous 4.5 inch core from ground surface through the glacial deposits and into the upper dolomite. Three borings were advanced into the upper dolomite in order to triangulate around each of the investigation areas. The cores were characterized for consistency, matrix color and secondary mottling, material type using the Unified Soil Classification System, field moisture, plasticity, cohesiveness, structure, weathering zone and carbonate status, observed secondary features, depositional environment or soil horizon, and Illinois State Geological Survey group, formation, or member name.
 

The hydrogeologic investigation was conducted to evaluate horizontal and vertical hydraulic conductivity, horizontal and vertical gradients, and to estimate groundwater flow velocity within the various strata. Piezometers were installed in each of the deep borings to monitor the upper dolomite. In each of the two study areas, a shallow soil boring was advanced adjacent to one of the bedrock piezometers, and a shallow piezometer constructed to monitor a suspected water bearing unit within the glacial deposits at the depth of previous monitoring wells. Soil samples from selected elevations were submitted for laboratory analysis for vertical permeability. Variable head tests were used to determine horizontal hydraulic conductivity. Differences in water levels in glacial and bedrock piezometers were used to determine vertical gradients between the two formations and to establish the potential for downward migration from the unit in the glacial deposits. Groundwater levels in the bedrock piezometers were used to site the location of a down gradient monitoring well at each location. The down gradient monitoring well was installed in the upper dolomite to extend the current monitoring program to the Class I groundwater. The site specific information obtained from this investigation was used along with information from an earlier recharge study, conducted on the monitoring well that the increasing 3H levels were observed in, and modeling to determine the cause of radionuclide migration.
 
 





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Estimating Evapotranspiration in a Groundwater Fed Wetland in Southwestern Wisconsin­Traditional and Geochemical Approaches

R. Brandon Lott, University of Wisconsin, Madison, WI

Randy J. Hunt and Ken W. Potter, U.S. Geological Survey, Madison, WI





Understanding the terms of the wetland hydrologic budget is important for successful mitigation of wetland losses. Traditional estimates of water balance terms generally include calculations that use limited and off-site data. In this study, traditional Penman and Thorntwaite methods to estimate potential evapotranspiration (PET) are being compared to estimates of evapotranspiration (ET) from isotope and solute budgets in adjoining natural and constructed wetlands in Wisconsin. These methods are also being compared to measurements of ET estimated from lysimeter and water table measurements.
 

Preliminary data collected during the 1995 growing season indicate that the Penman and Thorntwaite methods do not indicate significant differences between the natural and constructed sites. They do, however, indicate differences from ET rates estimated using the lysimeters. Specifically, both the Penman and Thorntwaite methods show dramatic decreases in rates during the late growing season (September and October), while the natural wetland lysimeter indicates ET rates equal to those observed in mid- summer. The discrepancies between estimated and observed ET rates can have a significant effect on interpretation of water movement in the capillary fringe of this wetland system, particularly groundwater inflow/outflow and solute transport.
 

Future work will include analysis of solute and isotope data collected in the shallow groundwater system at the two sites. Water isotope (18O and 2H) profiles will be constructed at 3 week intervals during the growing season to elucidate the effect of ET on the isotopic signatures of groundwater and precipitation in the root zone. A simple stable isotope mass balance will be used to estimate the ET flux during the 3 week intervals. The relationship between groundwater and ET will also be investigated using solute (Ca and Mg) balances in a similar manner. These geochemical approaches may be useful in understanding the interaction between groundwater inflow, precipitation, and evapotranspiration in the wetland root zone.
 
 





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Hydrogeological Criteria for a Low-level Radioactive Waste Site in Illinois­Update on the

LLRW Task Group's Proposal

Dr. Colin Booth, Northern Illinois University, DeKalb, IL and

Member, Illinois Low-Level Radioactive Waste Task Group





Low-level radioactive waste (LLRW) is not spent fuel rods or any of the similar hot, high-level wastes destined for entombment in Yucca Mountain! LLRW is used gloves, research and medical radioisotopes, resins and hardware from power plants, smoke detectors, etc; it will have decayed to background radiation levels within a few hundred years (mostly within a hundred). Federal law makes the states responsible for their LLRW disposal. Illinois requires a site for an (above-ground) engineered facility that will take only solid LLRW.
 

Following the controversial rejection of the proposed Martinsville site in 1992, the state legislature separated the responsibilities for site selection from that of licensing approval, and established an independent LLRW Task Group charged with developing site selection criteria based on technical and scientific considerations, not political ones. After the criteria are developed, the state scientific surveys will screen for promising locations, then the contractor (Chem-Nuclear) will investigate and identify sites, eventually proposing three to the Task Group. Once it accepts three sites as conforming to its criteria, the Task Group dissolves. The contractor then selects one site for detailed characterization leading to licensing application to the Department of Nuclear Safety.
 

After two years of discussion, deliberation, technical advice and feedback, and public comment on two draft versions, the Task Group has developed a set of criteria which it hopes to finalize in Fall 1996. The 25 criteria are presented as concise statements plus explanatory narratives, and address diverse environmental and technical considerations. They are concerned only with site characteristics, not the engineering design or the final dosage impact prediction, which are part of the licensing process.
 

Several of the criteria concern groundwater: e.g., protection of wells (#2), predictability of the site's geology and hydrogeology (#4), and avoidance of karstic areas (#5). Particularly, criterion #1 states "The hydrogeological conditions of the site must inhibit groundwater flow to the extent that groundwater resources are protected." The Task Group's earlier attempts to write criteria using specific cutoff values of hydrogeologic parameters became bogged down in oversimplification, contradictions, and number-quibbling in the comment feedback; it therefore chose instead to evaluate the site as an integrated hydrogeologic system that will minimize groundwater flow. Only the surveys' initial screening stage uses specified depths to aquifers as cutoff criteria. The "performance" approach imposes on the contractor a greater burden of hydrogeological investigation and positive demonstration of site suitability, rather than simple conformance to a checklist. It also explicitly defines the basis for site acceptance as being the best professional judgment of the members of the Task Group.
 
 







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Surface Barriers to Limit Water Infiltration into Underlying Waste or Contaminated Soil

David E. Daniel, University of Illinois, Urbana, IL





The problem of designing an effective surface barrier (also called "cap" or "cover") for a landfill or remediation project can be an enormously challenging task. There is a widely held misconception that surface barrier technology is well developed and works as expected. In fact, the technology is largely unproved, particularly in terms of long-term performance.
 

The most difficult problem with surface barriers is to provide a long-term barrier to infiltration of water. The materials that have traditionally been considered for the hydraulic barrier within surface barrier systems are low permeability compacted soil, geomembranes, and geosynthetic clay liners (GCLs). Data are presented to suggest that low permeability compacted soil is often a poor choice of materials. Unless the compacted soil liner is buried under a very thick layer of protective soil or covered by a geomembrane, the low permeability, clay rich, compacted soil is likely to desiccate and lose its low hydraulic conductivity. Differential settlement of a compacted soil liner from uneven compression of underlying waste or other causes is almost certain to produce cracks within the soil liner. Geomembranes do not suffer as much from these problems, but their design life is, at best, a few centuries. Geosynthetic clay liners (GCLs), which contain a thin layer of bentonite, are much better able to resist damage from freeze-thaw, desiccation, and differential settlement than compacted soil liners. Geosynthetic clay liners are particularly well suited for arid sites. The technology of GCLs is reviewed in some detail because of the technical attributes of GCLs in surface barrier applications.
 

Published case histories of the performance of surface barriers are summarized. There are many more published examples of failures than successes. While it appears that many surface barriers are failing to achieve fully their long-term design objectives, the actual long-term performance of surface barriers is largely unknown.
 

There is a great need to understand more about surface barriers. The primary challenges are: (1) developing surface barriers that can withstand large differential settlement, (2) using materials that can withstand seasonal changes in water content without cracking, (3) developing hydraulic barriers that will be essentially impermeable for hundreds of years or longer, and (4) verifying in the field that surface barriers can work and are working as well as anticipated.
 
 







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Sowing the Seeds, Public Awareness of the Role Geology Plays in Watershed Ecosystem Development

Myrna Killey and Daniel Barnstable, Illinois State Geological Survey, Champaign, IL





The Illinois Department of Natural Resources (DNR), of which the Illinois State Geological Survey (ISGS) is a part, has begun a program to assess the natural resources of selected regions of the state, defined on the basis of watersheds. The regions selected for study have formed Ecosystem Partnerships with DNR, directed by Local Partnership Councils (LPCs) that consist of individual citizens, conservation groups, municipal or county agencies, and any other entities that have an interest in the natural resources of a given area.
 

To provide the members of the LPCs with earth science information critical to the maintenance and restoration of each region's ecosystem elements, the ISGS is carrying out general assessments of the bedrock geology, glacial geology, soil conditions, groundwater resources, and landscape characteristics, and environmental conditions including geologic and hydrogeologic factors that affect maintenance of wetlands, distribution and mobility of agricultural chemicals, waste disposal, and groundwater protection. It is essential to emphasize the aspects of geology that influence habitat development and persistence. With this information available, the Local Partnership Councils can then define goals and strategies that will optimally use and protect their region's resources.
 

For the current fiscal year, the Illinois State Geological Survey, Illinois State Water Survey, Illinois Natural History Survey, and Waste Management and Research Center plan to produce reports on the natural resources of eight watershed areas throughout the state. These reports will contain a current description of pertinent geological, land use, and environmental considerations necessary for the LPCs' goal and priority setting.
 

We anticipate that this project will provide geologists with an excellent opportunity to communicate the importance of geologic information to the public, and to relate geologic information to ecosystems.
 
 







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Determination of Capture Zones and Recharge Areas of Pumping Wells in Laterally Homogeneous, Stratified Materials­A Generic Multi-Dimensional Model Simulation

Shannon Fulton, Lewis, Yockey, and Brown, Bloomington, IL

Larry Barrows, Illinois State University, Normal, IL





The success of any wellhead protection program is directly dependent on the accurate determination of wellhead protection areas, which are defined as surface and subsurface areas surrounding a well through which contaminants are reasonably likely to move towards and reach such well or well field. Based on this definition, a wellhead protection area can be broken down into surface areas which contribute water to a well (time-dependent recharge areas) and volumes which contribute water to a well within a specified time interval (time-of-travel capture zones). Overestimation of recharge areas and capture zones can led to unnecessary restrictions placed on development and usage of land incorrectly determined to be part of a wellhead protection area. Underestimation of recharge areas and capture zones provides only partial protection of the real wellhead protection area, increasing the risk of potential contamination.
 

To estimate and characterize time-of-travel capture zones and time-dependent recharge areas of typical alluvial aquifer systems, a series of generic, three-dimensional, finite-difference models were constructed to simulate flow to a pumping well with a screened interval of ten feet finished at a depth of 100 feet in a regional sand and gravel alluvial aquifer system with a 1:5000 regional hydraulic gradient. These generic models simulate differences in the configuration of time-of-travel capture zones and time-dependent recharge areas as hydraulic conductivity and pumping rate are varied.
 

The results of the model show that, for homogeneous material and a constant pumping rate of 40,000 cu ft/day, limited surface recharge occurs in close proximity to the well under low hydraulic conductivity (i.e. 10 ft/day) and surface recharge diminishes as the hydraulic conductivity is increased. When stratification of the geologic materials in introduced into the model under the same pumping conditions, surface recharge does not occur. When the pumping rate is increased, surface recharge occurs; however, the time of travel is very long (i.e. 180 years). These models demonstrate the importance of a thorough, three-dimensional analysis in wellhead protection studies
 
 





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GIS Application in Hydrogeology

Rey de Castro, GIS Solutions, Inc., Springfield, IL





Geographic Information System (GIS) in the broadest sense of the term refers to all automated systems used primarily for the management of maps and geographic data. The term GIS is used widely and generically to include many specific types of computer systems used for the mapping and processing spatial information. This includes systems devoted to mapping and engineering drawing, the query and management of geographic databases, or more complex geographic analysis or modeling. Currently, GIS is employed to conduct, environmental evaluation, land use studies, to locate a suitable site for a new business, to assess and develop oil, gas, coal, water, and other resources. The computer system utilized for the spatial analysis is ArcView developed by Environmental Science Research Institute (ESRI).
 

The ability to understand the spatial relationship or topology of features lies in the power of GIS. Topology is used to record and manipulate the relationships of map features and information in a GIS. A feature may either be a point or a line. A point may represent a well, chemical information at some location, or some object with a given coordinate whereas a line may represent a road, a fault, pipelines, or any continuous characteristic.
 

Data exists in all sizes and forms and GIS exists to aid the user manage the data in some manner. The Illinois State Water Survey (ISWS) and the Illinois State Geological Survey (ISGS) are some examples of sources for data within Illinois. The ISWS database can provide information regarding water quality, well location, driller, owner of the well drilled, driller, and among other things. The ISGS database not only provides well locations but geological data as well. Each facility houses information that may aid either a contractor, an insurance company, home owner, or some business person makes some type critical decision.
 

Data from the ISWS, ISGS, and United States Geological Survey (USGS) have been retrieved via the internet. These datasets are brought into some GIS computer system, ArcView, and from there we may undertake the spatial analysis of the features of interest to us. Information for Douglas County, Illinois was the only data extracted from ISWS and ISGS. Digital elevation map (DEM) and digital line graphs have been retrieved so that we may analyze the watershed, surface, slope, and other geomorphological aspects of a given area.
 
 







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Finding Water on the Web­The Growing Influence of the Internet

on the Water Resource Community

Faye Anderson, Southern Illinois University, Carbondale, IL





The water resources community has many information needs, related both to its creation and dissemination. The evolution of new information technologies is quickly changing the ways we interact with information and each other. As water resource professionals, we must concern ourselves with these new technologies in our efforts to understand, manage, and sustain global water supplies. And we have a need to minimize the costs these technologies impose upon us in both terms of time and money. This paper examines the impact of the World Wide Web and related information technologies on the water resources community in its research, education, consulting, and policy activities. A guide to existing water related Web sites will be presented, as well as effective techniques for finding water related information on the Web. Future developments concerning these technologies will also be discussed.
 
 





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Methods for Characterizing the Hydrogeology of an Underground Mine

for Disposal of Coal Combustion Residues

Steven Esling and Timothy McDonald, Southern Illinois University, Carbondale, IL

Edward Mehnert, Illinois State Geological Survey, Champaign, IL





Recent research has investigated the possible environmental impacts associated with pneumatic or hydraulic injection of coal combustion residues into deep underground coal mines; a disposal practice that offers distinct advantages over traditional disposal of these residues in landfills. The study area is a portion of a large abandoned underground mine in Illinois targeted for the disposal of the residues. Seven borings were drilled, including one that produced a nearly continuous core from the bedrock surface to the unit below the coal. The core was described in detail and selected intervals sampled for laboratory determination of porosity, permeability, and moisture content. Geophysical logs were taken of six of the seven boreholes. Nests of groundwater monitoring wells were installed in five the seven boreholes, for a total of twelve monitoring wells at the site; five for the collection of water quality samples and seven for monitoring hydraulic head.
 

The mine site has a favorable geologic and hydrologic setting for the disposal of coal combustion residues. Bounding strata have a low intrinsic permeability as indicated by packer tests and a theoretical analysis of groundwater flow into the mine. At present the target panels are dry. Air shafts and fracture zones may transmit underground water from shallow permeable units to the mine, but current groundwater discharge cannot flood the target panels. Packer tests suggest that the thick sequence of Pennsylvanian Strata over the mine have a bulk hydraulic conductivity less than 1e-8 cm/s. Water samples collected from the coal and from strata above the coal are nonpotable.
 
 







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RBCA: Design/Development/Impact

Gerald Phillips, Region 5, U.S. Environmental Protection Agency, Chicago, IL





My presentation will summarize Risk Based Corrective Action (RBCA), its ASTM development history, and its role in redevelopment of property. The subject of risk management is becoming more accepted, but many of the policy options remain controversial. Risk management is becoming the focus of discussion as the U.S. EPA's corrective action decision making tool of choice. I will also present a summary of the current status of the Agency's efforts related to risk management tools, with an emphasis on RCRA subtitles C and 1 as well as their relationships to Region 5's Brownfield efforts.
 
 







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Detailed Geologic Mapping of Illinois in Three Dimensions for

Aquifer Characterization and Groundwater Protection

Dr. William W. Shilts, Chief, Illinois State Geological Survey, Champaign, IL





There are 1,076, 1:24,000-scale quadrangles in Illinois; all have been covered by mapping at some scale at some time. Modern, federally-funded mapping, mostly in southern Illinois, has produced over 40 modern 1:24,000-scale geology maps over the past decade. Bedrock mapping in Chicago, by contrast, is at various scales and dates from the 20's and 30's. The major challenge raised by the opportunity to map the geology of Illinois systematically is to complete the task in a timely manner in a uniform format. Present funding levels from all sources will allow us to complete 2 to 4 quadrangles per year ­ clearly new sources of funds and personnel must be found if the state is to be mapped in the next half century.
 

In Illinois, a thick (200'+) cover of glacial deposits, including sand and gravel deposits which constitute the aquifers from which half of our invaluable water resources are derived, comprises the material in which most of our wastes are buried and our infrastructure is rooted. Therefore, it is imperative that geologic maps in most of Illinois depict conditions at depth ­ that we map the state in three dimensions. Furthermore, the bedrock beneath the glacial cover contains energy resources and is itself a resource, certain compositions being suitable for aggregate used in infrastructure construction and repair.
 

From ecosystem reconstruction to urban/suburban planning, geological maps depicting the material below our feet are indispensable to the state. They have been made and will be made as questions of groundwater supply/protection, hazardous waste disposal, and other issues arise. The fact that they can now be made digitally means that maps can be continuously and easily updated, rather than redone time a new issue arises. Publications and experience in Illinois and other states consistently indicate that the economic benefits of geologic mapping far outweigh its costs; the environmental and economic security they provide to Illinois citizens should be obvious from the state's long history of support of the Geological Survey and its map products.
 
 







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The Illinois Groundwater Consortium­Research on the Effects of Agricultural Chemicals

and the Floods of 1993 and 1995

Dr. Victoria Molfese, Southern Illinois University, Carbondale, IL





Findings by Consortium researchers provide information on the link between various pesticides and possible health risks, the movement and leaching of fertilizers and herbicides through gravel fill during normal and flood conditions, and chemical cleanup options, lowering water contamination through post-emergent application of herbicides, the effectiveness of artificial wetlands in reducing fertilizer pollution, recommendations for protecting wells from contamination, and the successfulness of a community-based well-sampling program. The goals of the research program currently underway are to provide information on the effects of the midwest floods of 1993 and 1995.
 

The floods have provided unique opportunities to investigate a variety of economically important issues. It appears that the ecological system of the Mississippi flood plain has been changed dramatically because of: the loss of vegetative cover and topsoil; soil contamination due to fertilizer, herbicide, coliform bacteria, and heavy metal sediment; and movement of herbicides, fertilizers and other contaminants into surface and groundwater. Important questions need to be addressed which pertain to what the long- term effects will be; how to facilitate the recovery of agricultural areas; what the implications will be for agriculture, wildlife, and recreational lands; how recovery of farmland and town sites are affected by the geological conditions which underlie them; and how individual homeowner and farmer interests can be balanced in order to qualify for government loan insurance.
 

Some of the work needed to answer some of these questions is being addressed by using data obtained by Consortium researchers during normal condition to compare with data obtained during flooded conditions to examine fertilizer, herbicide and pesticide transport in alluvial aquifers, watersheds, and in the subsurface; changes in water quality in public water supply wells; changes in and recovery of vegetation in flooded regions, changes in aquatic ecosystems and soils; and studies of floodplain management and ecosystem management after the flooding. This work, which builds on previous work done by the Illinois Groundwater Consortium, has already begun to yield publication in prominent journals and magazines that inform the research community and the public of the Consortium's findings. It is anticipated that the results of the Consortium projects will provide a foundation upon which public policy makers working on land use or groundwater protection issues in flood plain areas can base decisions.
 
 







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An Educational and Cost-Effective Program for the Assessment of Nitrate and Coliform Bacteria in Rural Domestic Wells in Illinois

Joseph Karny, Illinois State Water Survey, Champaign, IL





This voluntary and cooperative well-water sampling program, funded by the Illinois Groundwater Consortium, involved two local communities and educated high school students about the dangers of groundwater contamination. With the aid of FFA chapters in Paxton-Buckley-Loda (PBL) High School and Lincoln Community High School, over 300 rural, private drinking water wells were tested for nitrate, total coliform and Escherichia coli bacteria. In return for their participation and assistance, the ISWS provided educational outreach services to each FFA chapter, as well as an award of one thousand dollars.
 

Press releases, announcements mailed to rural residents and farm co-ops, and posters created by FFA students were used to alert well owners to this program. At each high school, the FFA chapters distributed "sampling kits" during designated distribution periods. The kits contained sample bottles, an instruction sheet, and a short questionnaire which asked for information about the well (age, depth, type, siting, etc.). Residents collected their own well water samples on specified collection dates and returned them to the high school. Well water testing was provided free of charge to participating residents and all received a confidential set of results, along with information about safeguarding their drinking water and treating contaminated wells.
 

Water samples were collected in late February and early April of 1995 in the PBL and Lincoln areas, respectively. A second round of testing was conducted in October and November 1995 in the PBL area, and in late February 1996 in the Lincoln district. Of the 291 rural, private wells examined during the first round, 57% of those in the PBL area and 48% from the Lincoln area were retested. While none of the wells sampled in the PBL area exceeded the safe drinking water standard for nitrate, nearly 20% of those from the Lincoln area did. The average nitrate detections were 0.13 and 7.90 mg-N/L for the PBL and Lincoln samples, respectively. Of the 461 well water samples tested overall, total coliform and E.coli bacteria were detected in 94 (20.4%) and 16 (3.47%), respectively. Approximately 80% of the bacteria detections were in samples from the Lincoln area.
 

The sharp contrast in the extent of nitrate and bacterial contamination between the PBL and Lincoln well water samples is largely attributable to the predominant hydrogeologic conditions in each study area. These factors in turn, largely determine the size, depth and method of construction for private well installations. Roughly 90% of the wells in the PBL area are drilled wells that tap aquifers 50 or more feet below ground. In the Lincoln area however, more than one-third of the samples were collected from shallow-bored or dug wells. The average reported well depth in the PBL area was 151 feet, but only 61 feet in Lincoln.
 

For the majority of wells tested, contamination was uncommon. Nitrate and bacteria occurrences were more likely to be found however, in those wells which were located on active farmsteads, were of dug or bored construction, or were relatively shallow in depth.
 

It is recognized that this well water testing project was not a scientific, statistically random sampling of rural private wells, and that the conditions of sample collections were not controlled. However, this research has nonetheless provided important water quality information to many rural residents, as well as scientific data to the ISWS. The success achieved is directly attributable to the involvement of the FFA organizations, which provided this effort with "built-in" local support. The concerns of the participating well owners and their willingness to collect their own samples also served to greatly reduce costs and logistical problems. The cooperative nature of this sampling program had multiple advantages, and it is hoped that they will serve as a model for future efforts.
 
 





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The Effect of Septic Systems on Groundwater Quality in the Prairie Aquigroup and

Alexandrian-Maquoketa Aquifer, Campton Township, Kane County, Illinois

Kurt Kraske, Northern Illinois University, DeKalb, IL; now with Harza Environmental Services





Campton Township is a rapidly growing rural community located in the central portion of Kane County in northeast Illinois. The township consists of large residential areas, small businesses, and farmland which border the western suburbs of Chicago. Since most of the area is beyond the reach of municipal sewer networks, individual septic absorption systems are used extensively throughout the township to dispose of sewage produced by each household.
 

The majority of residential water wells in Campton township are located in close proximity to septic absorption fields and obtain water from the Prairie Aquigroup of the Alexandrian-Maquoketa Aquifer. The Alexandrian-Maquoketa Aquifer is composed predominantly of the Maquoketa Shale Group, which includes Ordovician age shales, argillaceous dolomites, and minor limestones. Within the Maquoketa Group, the dolomites of the Fort Atkinson Formation are permeable enough to yield small quantities of groundwater. However, the remainder of the Maquoketa consists of relatively impermeable shale with only small water bearing zones. Thin, laterally discontinuous Alexandrian units overlie the Maquoketa Shale Group and are made up almost entirely of fine-grained dolomites. In Campton Township, these dolomitic units are normally too thin to yield adequate quantities of water. A weathered and fractured zone extends from 50 to 100 feet below the bedrock surface and contributes to increased permeability in the upper portion of the Alexandrian-Maquoketa Aquifer. Many of the wells in the study area exploit this zone in order to yield a sufficient amount of water for household use. Overlying the irregular bedrock surface, the Prairie Aquigroup includes all of the unconsolidated glacial drift, alluvium, and other Holocene sediments. These locally confined units are recharged by precipitation and are in close hydraulic connection with the bedrock. Sand and gravel interbeds normally contain at least small amounts of water and are the most productive aquifer units in the Prairie Aquigroup. The largest sand and gravel deposits are found in the deep glacial valleys throughout the study area.
 

A basic geochemical analysis was focused on these aquifers and used to gain information about the effects of septic absorption systems on the groundwater found below Campton Township. Well water samples were analyzed for major cations and anions, with emphasis on nitrogen compounds. These analytes were not found in concentrations above health standards; however, their relative concentrations in the shallow and deep groundwater indicate that septic effluent contributes significantly to the geochemical system. In addition, the analysis reveals that there are areas in Campton Township where septic absorption fields may be failing to function properly.
 
 

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