Browsing by Author "Tipping, R.G."

Now showing 1 - 18 of 18
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    Bedrock geology of Minnesota: Postcard
    (Minnesota Geological Survey, 1996) Tipping, R.G.; Lusardi, B.A.
    This simplified geologic map shows the general distribution of rock types underlying Minnesota's landscape. Some of the rocks are 3.6 billion years old-the oldest found so far in the United States.
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    Geological mapping and 3D model of deposits that host ground-water systems in the Fargo-Moorhead region, Minnesota and North Dakota
    (Minnesota Geological Survey, 2005) Thorleifson, L. H.; Harris, K.L.; Berg, J.; Tipping, R.G.; Malolepszy, Z.; Lusardi, B.A.; Setterholm, D.; Anderson, F.
    The objective of the current project is to present an updated and enhanced depiction of the sediments and rocks within which ground-water systems occur across the Fargo-Moorhead region, to support further assessment of currently utilized and potentially usable ground-water resources in the region. To do so, existing geologic maps from North Dakota and Minnesota were compiled, interpreted, and integrated to produce two maps, one depicting the uppermost unconsolidated deposits (Surficial Geology; 1: 200,000), and the other depicting the uppermost rocks (Bedrock Geology; 1: 400,000). These maps were merged with a new interpretation of bedrock elevation and a compilation of readily available digital drillhole data for approximately 30,000 sites to produce a three-dimensional (3D) depiction of subsurface geology, extending from the land surface down to the top of the granites and other igneous and metamorphic basement rocks of Precambrian age that underlie the entire region.
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    Geology in support of groundwater management for the northwestern Twin Cities Metropolitan area
    (University of Minnesota, 2003) Runkel, A.C.; Tipping, R.G.; Mossler, J.H.
    The Paleozoic bedrock in the northwest part of the Twin Cities Metropolitan area (Fig. 1) has been increasingly relied upon as a source of potable water. Most municipal wells in the area are now constructed to draw water from Paleozoic bedrock because productive drift aquifers are uncommon and are more susceptible to contamination. Increased reliance on Paleozoic strata as a source of groundwater led to a request by environmental managers, led by the Metropolitan Council, for improved geologic maps of the area as well as a hydrogeologic characterization of the most heavily used aquifers and their intervening confining units, those in the siliciclastic-dominated, Upper Cambrian part of the Paleozoic section. Hydrogeologic characterization combined with mapping provides a geologic framework for the northwest metro area that is of greater usefulness to environmental managers because it will increase the accuracy of groundwater protection plans, as well as predictions of aquifer productivity. Our hydrogeologic investigation is focussed on detailed characterization of the Upper Cambrian aquifer commonly referred to as the “Franconia-Ironton/Galesville” or “FIG” aquifer, using recently developed borehole geophysical techniques (Paillet and others 2000; Runkel and others, 2003). The tentative strategy for communities in the northwest metro area is to use the FIG aquifer as the principle source of potable water. Information was also collected and synthesized, to a lesser extent, on the Eau Claire and St Lawrence Formations, which are generally considered confining units above and below the FIG aquifer, and on the Mt Simon Sandstone, which is considered a less desirable alternative to the FIG as a source of water.
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    Ground-water data management: The County Well Index
    (Minnesota Geological Survey, 1991) Wahl, T.E.; Tipping, R.G.
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    A Hydrogeologic and Mapping Investigation of the St. Lawrence Formation in the Twin Cities Metropolitan Area
    (University of Minnesota, 2006) Runkel, A.C.; Mossler, J.H.; Tipping, R.G.; Bauer, E.J.
    This report summarizes the results of a two year project conducted by the Minnesota Geological Survey to map the Upper Cambrian St. Lawrence Formation and investigate its hydrologic properties in the Twin Cities Metropolitan area (TCMA). Funding was provided by the Minnesota Department of Health. Final products are a map delivered in electronic format that can be used with Arcview 3.2 GIS software, and this informal report. Our hydrogeologic study indicates that the St. Lawrence Formation commonly has a moderate to high horizontal hydraulic conductivity across all of the study area. In conditions of shallow burial beneath younger bedrock it is most similar in the development of secondary pores and measured hydraulic properties to fractured carbonate rock aquifers. Discrete intervals with secondary pores have a high horizontal hydraulic conductivity whereas rock between these intervals are orders of magnitude lower in conductivity. The properties of the St. Lawrence Formation in a vertical direction are not as wellunderstood, but available data are consistent with the traditional classification of the formation as an aquitard. However, the integrity of the formation as an aquitard in a vertical direction, particularly under conditions of shallow burial such as where it is uppermost bedrock, has not been rigorously tested, and may be markedly variable across the TCMA. This is chiefly because vertical fractures play an important role in determining aquitard integrity, and the distribution of such fractures is poorly understood. Suggestions for additional research that might lead to a better understanding of aquitard integrity are made at the end of this report.
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    Hydrogeology of Scott County
    (Minnesota Geological Survey, 2008) Tipping, R.G.; Runkel, A.C.
    This report describes the hydrogeology of Scott County, based on the assembly of existing data and data acquired as part of this investigation. The focus of this report is on bedrock hydrogeology, with additional discussion of the hydrogeology of Quaternary unconsolidated deposits. The report is intended to supplement maps provided as part of the Scott County Geologic Atlas revision, produced with the support of the Scott County Board of Commisioners.
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    Karst Features of Minnesota
    (Minnesota Geological Survey, 2002) Alexander, E. Calvin, Jr.; Tipping, R.G.
    Southeastern Minnesota is part of the Upper Mississippi Valley Karst (Hedges and Alexander, 1985) that includes southwestern Wisconsin and northeastern Iowa. Karst lands in Minnesota are developed in Paleozoic carbonate and sandstone bedrock. A significant sandstone karst has developed in Pine County (Shade and others, 2001). Most surficial karst features such as sinkholes are found only in those areas with less than fifty feet of sedimentary cover over bedrock surface (Gao and others, 2002). Since the early 1980s, the Minnesota Geological Survey and Department of Geology and Geophysics at the University of Minnesota have been mapping karst features and publishing various versions of their results in the form of 1:100,000 scale County Geologic Atlases. In the mid 1990s, the Minnesota Department of Natural Resources was assigned responsibility for the hydrogeology portions of the County Atlases and is now responsible for the karst mapping. Dalgleish and Alexander (1984), Alexander and Maki (1988), Witthuhn and Alexander (1995), Green and others (1997), Shade and others (2001), and Tipping and others (2001) published sinkhole distribution maps for Winona, Olmsted, Fillmore Counties, Leroy Township, Pine and Wabasha Counties respectively. Published Atlases of Washington, Dakota, and the counties of the Twin Cites Metro area contain limited information on sinkhole occurrences. A karst feature database of Southeastern Minnesota has been developed that allows sinkhole and other karst feature distributions to be displayed and analyzed across existing county boundaries in a GIS environment. The central DBMS is a relational GIS-based system interacting with three modules: spatial operation, spatial analysis, and hydrogeological modules. Data tables are stored in a Microsoft ACCESS 2000 DBMS and linked to corresponding ArcView shape files. The current Karst Feature Database of Southeastern Minnesota was put on a Citrix Window 2000 server accessible to researchers and planners through networked interfaces. The karst inventory points were point features such as sinkholes, springs, and stream sinks extracted from the karst feature database of Southeastern Minnesota. Both inventory points and karst feature database are updated on regular basis. This research was supported with funding from the Minnesota Department of Health.
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    M-104 Bedrock geology and structure of the seven-county Twin Cities Metropolitan Area, Minnesota
    (Minnesota Geological Survey, 2000) Mossler, J.H.; Tipping, R.G.
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    Mapping and hydrogeologic research in support of groundwater management, Shakopee Mdewakanton Sioux Community, Scott County, Minnesota
    (University of Minnesota, 2008) Runkel, A.C.; Tipping, R.G.; Meyer, G.N.
    This report summarizes a project by the Minnesota Geological Survey (MGS) to conduct research intended to provide basic geologic data and technical interpretations pertinent to groundwater management strategies for the tribal land of the Shakopee-Mdewakanton Sioux Community (SMSC), and surrounding areas, in Scott County, Minnesota. The major project tasks included production of a number of maps, crosssections, and 3-dimensional images that depict Paleozoic bedrock and overlying Quaternary strata. An evaluation of the hydrogeologic attributes of the bedrock is also included, with emphasis on the Franconia Formation and Ironton-Galesville sandstones which are of increasing importance to the SMSC as a source of water.
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    OFR 07-02; Geology in support of ground-water management for the Twin Cities Metropolitan Area, Metropolitan Council Water Supply Master Plan Development - Phase I
    (University of Minnesota, 2007) Meyer, G.N.; Tipping, R.G.
    This report summarizes work by the Minnesota Geological Survey to provide the Metropolitan Council, as part of their Phase I Water Supply Master Plan, with information to help characterize recharge to metropolitan area bedrock aquifers. The Council requested a better understanding of the surface and subsurface distribution of unconsolidated deposits overlying bedrock, with the goal of identifying preferential water pathways from the land surface to bedrock. To this end, the Minnesota Geological Survey provided: 1.) a seamless surficial geology map of the greater Twin Cities metropolitan area; 2.) a collection of historic metro-wide water chemistry data used to prioritize areas for subsurface mapping – 27 new samples were collected in northwestern Hennepin County where data was sparse; and 3.) a three dimensional model of unconsolidated deposits from the land surface to bedrock for the northwest metropolitan area, hereafter referred to as the geologic framework model.
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    OFR 07-05, The Lake Elmo Downhole Logging Project: Hydrostratigraphic Characterization of Fractured Bedrock at a Perfluorochemical Contamination Site
    (University of Minnesota, 2007) Runkel, A.C.; Mossler, J.H.; Tipping, R.G.
    The Minnesota Pollution Control Agency (MPCA) and Minnesota Department of Health are actively involved in detecting and remediating perfluorochemical contamination of groundwater in the Twin Cities Metropolitan area. A perfluorochemical plume in the Lake Elmo area of Washington County contaminated the water supply of more than 285 residents in that area. As a result, a municipal water system has been connected to more than 200 residents, and domestic wells in the area were abandoned. This report summarizes the results of a project by the Minnesota Geological Survey to collect downhole geophysical data from nearly 200 of these domestic wells before they were sealed as part of the abandonment process. Over 95 percent of these wells extract water from the lower one-half of the St. Peter Sandstone or upper part of the Shakopee Formation, with the remaining wells open to overlying unconsolidated glacial deposits. The downhole geophysical data are used to determine rock properties and flow characteristics of these bedrock aquifers. The results will be used by the MPCA to help better determine the three dimensional extent of contamination, and in particular provide insight into the role of groundwater flow through fractures. Such information will assist the MPCA in determining appropriate remedial monitoring actions in a cost effective manner.
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    OFR 07-07, Bedrock geology, topography, and karst feature inventory of Steele, Dodge, Olmsted and Winona Counties
    (Minnesota Geological Survey, 2007) Tipping, R.G.; Mossler, J.H.; Alexander, E. Calvin, Jr.; Gao, Y.; Green, Jeffrey A.; Alexander, S.C.
    Final Project Report Regulating contaminant sources and addressing remediation of contaminated sites is difficult in sensitive karst areas because of the unpredictable nature of groundwater movement in solution-weathered bedrock. In this project, the Minnesota Departments of Health, Natural Resources and the Minnesota Pollution Control Agency partnered with the Minnesota Geological Survey and the Department of Geology and Geophysics – University of Minnesota, to develop better tools to understand and manage point and non-point sources on contamination in karst terrains. Contaminant Management in the Karst Region Contract with MGS, also includes summary information for 319 Karst Demonstration Project
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    OFR08-06, Geologic Investigations to Support Ground-Water Management II, Rochester metropolitan area, Minnesota, Project Summary Report to Rochester Public Utilities
    (University of Minnesota, 2008) Tipping, R.G.; Runkel, A.C.
    This informal report describes the results of a project in which the Minnesota Geological Survey constructed bedrock geologic and hydrogeologic framework models for the greater Rochester metropolitan area. The framework depicts aquifer and aquitard geometery that will be used for a ground-water model being developed by the United States Geological Survey (USGS). Rochester Public Utilities (RPU) provided the funding for both the Minnesota Geological Survey and USGS roles in this effort. It is anticipated that the model will also provide a useful visual tool for public education and discussion of issues related to ground water in the greater Rochester metropolitan area. Detailed data gathering and interpretation was focused on Cascade, Haverhill, Marion, and Rochester Townships comprising the greater Rochester metropolitan area. Surfaces of the geologic and hydrogeologic units in the framework models were extended beyond the county boundary to accommodate hydrologic boundary conditions to be used in the ground-water model.
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    OFR08-07, Washington County Landfill Logging Project: Borehole Geophysical Tests for Presence of Fracture Flow at a Perfluorochemical Contamination Site
    (University of Minnesota, 2008) Runkel, A.C.; Tipping, R.G.; Anderson, J.R.
    The Washington County Landfill located near Lake Elmo, Minnesota is a source of perfluorochemicals that have contaminated groundwater in the area. A project completed in 2007 by the Minnesota Geological Survey (Runkel and others, 2007) determined that flow through fractures is an important part of the bedrock hydrogeologic system in an area of Lake Elmo one to two miles southwest of the landfill. The objective of this project, sponsored by the Minnesota Pollution Control Agency (MPCA) was to collect borehole geophysical data from three bedrock monitor wells within a few hundred yards of the landfill (Fig. 1) in an effort to identify bedrock fractures and characterize their hydraulic properties in the open-hole intervals of these wells. This information will allow the MPCA to determine if there are preferential groundwater flow paths in the bedrock at the Washington County Landfill, an important consideration for devising remediation and monitoring strategies at the site.
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    OFR91-05, Geologic factors affecting the sensitivity of the Prairie du Chien-Jordan aquifer
    (Minnesota Geological Survey, 1991) Setterholm, D.R.; Runkel, A.C.; Cleland, J.M.; Tipping, R.G.; Mossler, J.H.; Kanivetsky, R.; Hobbs, H.C.
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    RI-61 Hydrogeology of the Paleozoic bedrock in southeastern Minnesota
    (Minnesota Geological Survey, 2003) Runkel, A.C.; Tipping, R.G.; Alexander, E. Calvin, Jr.; Green, Jeffrey A.; Mossler, J.H.; Alexander, S.C.
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    Southeastern Minnesota regional ground-water monitoring study
    (Minnesota Geological Survey, 1994) Tipping, R.G.
    This report summarizes analytical results obtained from water samples taken from 158 wells in southeastern Minnesota from October 1992 to January 1993. The sampling and analysis were part of a regional assessment of ground-water quality sponsored by the Southeast Minnesota Water Resources Board with funding from, and in cooperation with, the Minnesota Board of Soil and Water Resources (BWSR), the Minnesota Pollution Control Agency (MPCA), the Department of Geology at Winona State University (WSU), and the Minnesota Department of Agriculture (MDA). The purpose of the project was to acquire baseline data on ground-water quality of the major bedrock aquifers in this region. The primary water-bearing stratigraphic units that make up these aquifers, in order of elevation from highest to lowest, are the Cedar Valley Formation and the Galena Group; the St. Peter Sandstone; the Prairie du Chien Group; the Jordan Sandstone; and the Franconia, Ironton, and Galesville formations.