Developing a Web Site to Provide Geologic Data and Map Products for Allen County, Indiana

This poster was presented at the 2007 meeting of the Digital Mapping Techniques Conference in Columbia, South Carolina, May 20-23, 2007.The Internet is becoming the medium of choice for delivering geologic information to both technical users and the general public. The Indiana Geological Survey (IGS) is currently creating a Web-based glacial and bedrock geologic map site for Allen County in northeastern Indiana. Allen County is the site of Fort Wayne, Indiana’s second largest city, and lies within IGS mapping and outreach priority areas based on population density and transportation corridors. This Web site provides detailed geologic information in an area that continues to experience pressure on natural resources by a large population and expanding transportation network. It is anticipated that the information from the Web site will be widely used by the general public and by industry and government entities. The Allen County Web site includes an Internet map server (IMS), as well as illustrations, educational summaries, and discussions of geologic maps, terrain images, and databases that complement the IMS. The site provides a front-end to the IGS enterprise geodatabases, which contain information used simultaneously for research and for viewing by the general public. The geodatabase systems allow maps and data to be efficiently created, managed, updated, and distributed. Maps provided on the Allen County Web site include: (1) digital elevation model terrain, (2) Landsat imagery, (3) surficial geology, (4) drift thickness, (5) bedrock topography, (6) bedrock geology, and (7) water-table elevation. Technical database information includes: (1) lithologic information compiled from water-well information in the Indiana Department of Natural Resources, Division of Water well records, (2) natural gamma-ray geophysical log data, (3) stratigraphic test hole data, and (4) petroleum-well data. The development of the Web site was funded by the IGS and the Central Great Lakes Geologic Mapping Coalition.U.S. Geological Surve

Preliminary Geologic Characterization of Indiana for Indoor-Radon Survey

The Indiana State Board of Health, with assistance from the U.S. Environmental Protection Agency (EPA), expanded the program to assess indoor-radon levels in homes in the state during the 1987-88 heating season. This report fulfills that request; it includes brief descriptions of bedrock and unconsolidated materials exposed at or near the surface in Indiana, divides the state into eight geologic regions, and describes the relative radon-potential of areas within those regions

Escherichia Colia Monitoring in the Spring Mill Lake Watershed in South-Central Indiana

The Spring Mill Lake watershed is located in the Mitchell Plateau physiographic section, a karst area developed on Mississippian limestones and dolostones in south-central Indiana. Spring Mill Lake is a man-made reservoir built in the late 1930s and is located in Spring Mill State Park. Within the park, ground water from subsurface conduits issues as natural springs and then flows in surface streams to Spring Mill Lake. Waters flowing from the springs in the park were analyzed to determine potential nonpoint-source contaminants entering Spring Mill Lake from 1998 to 2002. For this project, data-collecting sites were selected within the several subwatersheds of the Spring Mill Lake watershed, including the springs discharging from Donaldson Cave, Hamer Cave, Upper Twin Cave, Whistling Cave, Wind Cave, and the Rubble site. This paper reports on Escherichia coli concentrations and ambient water quality parameters of the springs, a stream, and the lake within Spring Mill State Park. Water samples for the analysis of E. coli were collected at the monitoring sites once during each quarter from August 1998 through February 2002. Ambient water-quality measurements were taken quarterly at the monitoring sites from August 1998 through May 2000. E. coli concentrations from the monitoring sites within the Spring Mill Lake watershed varied greatly from concentrations below the detection limit, \u3c1 most probable number (MPN) of organisms per 100 milliliters (mL) of water, to 980,000 MPN/100 mL. E. coliappears to be a potential health risk at several of the springs within the park, particularly at the spring at the Rubble site

Karst geology and hydrogeology of the Mitchell Plateau of south-central Indiana

The Mitchell Plateau of south-central Indiana is one of the iconic karst landscapes of the United States. The sinkhole-dimpled forests, fields, and farms; the extensive cave systems; and the deep windows into the groundwater system have fostered curiosity, exploration, and publication since the mid-1800s. This paper is designed to complement a field excursion to the classic features of this landscape. Included are literature reviews focused on three karst basins of the Mitchell Plateau: Mill Creek–Mosquito Creek, Bluespring Caverns, and Lost River. Geomorphic, hydrologic, and geochemical data are synthesized in the modern context of our understanding of epigenetic karst. Revealed are three styles of karst basin: (1) small, shallow karst aquifers strongly controlled by meteoric recharge and epikarst percolation; (2) intermediate-size karst aquifers with significant base flow and surface-water–groundwater interaction; and (3) regional aquifer systems with outcrop belt recharge, downdip transport into confinement with long water-rock interaction times, and artesian flow or entrainment of mineralized waters through fractures into springs or surface waters. Quaternary glaciation has greatly influenced the vertical position of base level through river incision and sediment aggradation; conduit development is controlled by proximity to the major rivers and the stratigraphic position of conduits

Water-quality characteristics and contaminants in the rural karst-dominated Spring Mill Lake watershed, southern Indiana

The Spring Mill Lake watershed is located in the Mitchell Plateau, a karst area that developed on Mississippian carbonates in southern Indiana. Spring Mill Lake is a reservoir built in the late 1930s and is located in Spring Mill State Park. Within the park, groundwater from subsurface conduits issues as natural springs and then flows in surface streams to the lake. From 1998 to 2002, surface and subsurface hydrology and water quality were investigated to determine the types and sources of potential contaminants entering the lake. Water samples collected during base flow and a February 2000 storm event were analyzed for selected cations, anions, trace elements, selected U.S. Environmental Protection Agency (EPA) primary and secondary drinking-water contaminants, nitrogen isotopes, suspended solids, Escherichia coli, and pesticides. All of the water samples met the EPA drinking-water standards for inorganic constituents, except those collected at five sites in August 1999 during a drought. Nitrate nitrogen (NO3-N) concentrations were highest during base-flow conditions and displayed a dilutional trend during peak-flow periods. The NO3-N concentrations in water samples collected during the 2001 spring fertilizer applications tended to increase from early to late spring. All of the δ15N values were low, which is indicative of either an inorganic source or soil organic matter. Storm discharge contained increased concentrations of total suspended solids; thus, storms are responsible for most of the sediment accumulation in the lake. E. coli levels in 24% of the samples analyzed contained a most probable number (MPN) greater than 235/100 mL, which is the maximum acceptable level set for recreational waters in Indiana. E. coli does appear to be a potential health risk, particularly at Rubble spring. The sources of E. colifound at this spring may include barnyard runoff from a horse barn or wastes from a wastewater treatment facility. The pesticides atrazine, metolachlor, acetochlor, and simazine were detected during th