south-central minnesota groundwater monitoring of the mt. simon...

South-Central Minnesota Groundwater Monitoring of the Mt. Simon AquiferJames A. Berg and Scott R. PearsonMinnesota Department of Natural ResourcesEcological and Water Resources DivisionSt. Paul, Minnesota

November 2012

Funding for this project was provided by the Minnesota Environment and Natural Resources Trust Fund as recommended by the Legislative Commission on Minnesota Resources (LCCMR).

This is the final project report of Result 2 of the LCCMR project titled “South-Central Ground-water Monitoring and County Geologic Atlases” (M.L. 2008 Chap. 367, Sec. 2 Subd. 4 (h)).

AuthorsJames A. BergScott R. Pearson

Contributors and ReviewersJeanette LeeteNeil Cunningham Bob TippingTony RunkelJohn Mossler

If you have questions or would like additional information, please contact James Berg at 651-259-5680.

Minnesota Department of Natural Resources500 Layfayette Road North | Saint Paul, MN 55155-4040 | www.dnr.state.mn.us | 651-296-6157 Toll free 888-MINNDNR | TTY 651-296-5484

This report is available in additional formats upon request, and online at www.dnr.state.mn.us

Last version: Version 3.1, June 2011Current version: Version 3.2, November 2012 (text update)

Contents

Abstract......................................................................................................................................................6

Introduction and Purpose.........................................................................................................................7

Geology of South-Central Minnesota.......................................................................................................8

Investigation Methods................................................................................................................................9 Site selection Drilling methods and well construction Aquifer interval selection for monitoring Geophysical well logging Well development Groundwater sample collection Specific capacity procedures and results Continuous water level measurements

Thickness of the Mt. Simon Aquifer Near the Western Subcrop.........................................................13

Groundwater Movement and Potentiometric Surface - Mt. Simon Aquifer........................................13

Geochemistry...........................................................................................................................................14 Groundwater Residence Time Stable isotopes, 18O and deuterium Source water temperature and mixing Evaporation of source water Major ions Trace elements

Hydrogeology Illustrated by Cross Sections and Hydrographs from Observation Well Nests.......18 Cross section A-A’ and Severence Lake WMA hydrograph Cross section B-B’ and Sibley County landfill property hydrograph Cross section C-C’ and Norwegian Grove WMA hydrograph Cross section D-D’ and Peterson unit hydrograph Cross section E-E’ and Courtland West/Nicollet Bay hydrographs Cross section F-F’ and Helget-Braulick WMA hydrograph Cross section G-G’ and Bergdahl WMA hydrograph Cross section H-H’ and Case WMA hydrograph Cross section I-I’ and Madelia WMA hydrograph Cross section J-J ‘and Long Lake WA hydrograph Cross section K-K’ and Exceder WMA hydrograph Cross section L-L’ and Rooney Run WMA hydrograph

Paleohydrology and recharge estimates...............................................................................................22 Southern area recharge Northern area recharge

4 South-Central Minnesota Groundwater Monitoring of the Mt. Simon Aquifer

2009 Groundwater Appropriation..........................................................................................23 Southern area appropriation Northern area appropriation

Conclusions............................................................................................................................24

References..............................................................................................................................25

Attachments Section

Tables......................................................................................................................................27 1: Well summary 2: Specific capacity and water level data summary 3: Field sample collection and handling 4: Residence time indicators, stable isotopes, and selected trace elements 5: Selected anion and cation data

Figures....................................................................................................................................33 1: Mt. Simon observation well nest locations 2: Cambrian and older stratigraphy in study area 3: County and state Paleozoic bedrock map 4: Mt. Simon Sandstone thickness 5: Mt. Simon potentiometric surface and groundwater flow directions 6: Cross section Z-Z’, Mt. Simon potentiometric surface 7: Carbon-14 residence time data from the shallower aquifers at each observation well nest 8: Mt. Simon carbon-14 residence time, potentiometric surface, and groundwater flow directions 9: Stable isotope data compared with North American meteoric line 10: Ternary diagram-relative abundances of major cations and anions 11: Mt. Simon sulfate concentrations (mg/l), and groundwater flow directions 12: Mt. Simon chloride concentrations (mg/l), and groundwater flow directions 13: Mt. Simon arsenic concentrations (mg/l), and groundwater flow directions 14: Precipitation departure from normal October 2009-September 2010 15a: Cross section A-A’ 15b: Severance Lake WMA hydrograph 16a: Cross section B-B’ 16b: Sibley County landfill hydrograph 17a: Cross section C-C’ 17b: Norwegian Grove WMA hydrograph 18a: Cross section D-D’ 18b: Peterson Unit hydrograph 19a: Cross section E-E’ 19b: Courtland West Unit hydrograph 19c: Nicollet Bay Unit hydrograph 20a: Cross section F-F’

5South-Central Minnesota Groundwater Monitoring of the Mt. Simon Aquifer

20b: Helget Braulick WMA hydrograph 21a: Cross section G-G’ 21b: Bergdahl WMA hydrograph 22a: Cross section H-H’ 22b: Case WMA hydrograph 23a: Cross section I-I’ 23b: Madelia WMA hydrograph 24a: Cross section J-J’ 24b: Long Lake WA hydrograph 25a: Cross section K-K’ 25b: Exceder WMA hydrograph 26a: Cross section L-L’ 26b: Rooney Run WMA hydrograph 27: Mt. Simon recharge interpretation 28: Generalized cross section Z-Z’ and geochemical data 29: Cross section Z-Z’, Mt. Simon recharge and discharge 30: Mt. Simon observation well nest locations and 2009 groundwater appropriation

Appendix A: Geological/Geophysical Logs and Well Construction Diagrams..................77 Geological Log Legend Severance Lake WMA Rooney Run WMA Swan Lake WMA - Peterson Unit Norwegian Grove WMA Swan Lake WMA - Nicollet Bay Unit Madelia WMA Long Lake WA Lake Hanska WA Helget Braulick WMA Exceder WMA Swan Lake WMA - Courtland West Unit Case WMA Bergdahl WMA Sibley County Landfill

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Abstract

The deepest bedrock aquifer of south central/southeastern Minnesota, including the Minneapolis/St. Paul metro area, is the thick (50 to 200 feet) Cambrian sandstone Mt. Simon aquifer. It supplies all or some of the water used by over one million Minnesotans. The few water level measurements available from this aquifer in the Mankato and Minneapolis/St. Paul metro area indicate declining water levels in areas where water is being withdrawn for municipal and industrial use. To better understand the recharge dynamics of the Mt. Simon aquifer the western and northern edge of the Mt. Simon aquifer, where it is not overlain by relatively impermeable Paleozoic shale formations, was considered the most likely area for aquifer recharge. This edge of the Mt. Simon aquifer was investigated and character-ized through observation well installations, water level monitoring, groundwater chemical analysis, and aquifer capacity testing to help determine recharge pathways and sustainable limits for this aquifer. Most data collected for this study are derived from the wells installed at 14 locations by contracted drilling companies.

The combination of chemical residence time indictors, continuous water level data from nested well locations, and a general knowledge of the regional hydrostratigraphy, show an aquifer with a very slow recharge rate from a large source area located south of the Minnesota River and a smaller source area located in the northern portion of the study area. The younger 14C residence time values of Mt. Simon groundwater (7,000-8,000 years) from this project roughly correspond to a time after the last ice sheet had receded from southern Minnesota suggesting groundwater in the Mt. Simon aquifer in this region began as precipitation that infiltrated during the post-glacial period. The stable isotope data of oxygen and hydrogen support this conclusion. A recharge estimate of the Mt. Simon aquifer south of the Min-nesota River based on these minimum residence time data suggests a recharge rate of approximately 0.49 cm/yr. The resulting 1.2 billion gallons/year of recharge from the southern source area is less than the amount of groundwater used from the most recent year for which data are available (2009). The results of this project suggest that Mt. Simon aquifer groundwater use in the study area, for the most recent period (2009), may be more than the replacement rate along the Mt. Simon subcrop. Continued monitoring of the observation wells in this region should help determine if more water is used than is being replaced by recharge.

A major accomplishment of this project is the creation of a network of observation well nests along the western margin of this aquifer system. Long term water level data and geochemistry from these wells will enable future hydrologists to evaluate the local and regional effects of Mt. Simon groundwater pumping in the region.


Introduction and Purpose

The 2008 and 2009 legislatures allocated funding from the Environment and Natural Resources Trust Fund for an aquifer investigation, mapping, and monitoring project in south-central and east-central Minnesota (Figure 1). The 2008/2009 allocations provide $4,295,000 for a 4-year project. The allocation is being shared by the Department of Natural Resources (DNR, $2,769,000) and the Minnesota Geological Survey (MGS, $1,526,000) to evaluate the Mt. Simon aquifer and produce geologic atlases. The purpose of this report is to compile, summarize, and interpret data collected from the first phase of the DNR portion of this project as required by the statute (ML 2008, Chap. 367, Sec. 2, Subd. 4 (h)). A report summarizing the sec-ond phase of the project west and northwest of the Twin Cities Metropolitan area is scheduled for comple-tion June 30, 2012.

The deepest bedrock aquifer of south central/southeastern Minnesota, including the Minneapolis/St. Paul metro area, is the thick (50 to 200 feet) Cambrian sandstone Mt. Simon aquifer. It supplies all or some of the water used by over one million Minnesotans. The few water level measurements available from this aquifer in the Mankato and Minneapolis/St. Paul metro area indicate declining water levels in some parts of these areas where water is being withdrawn for municipal and commercial use. While efforts currently are underway through other agency and additional Minnesota Department of Natural Resources projects to lo-cally map and understand these depressed Mt. Simon water level areas, we believed a project to regionally understand the recharge dynamics of the Mt. Simon aquifer was needed. The western and northern edge of the Mt. Simon aquifer (Figure 1), where it is not overlain by relatively impermeable Paleozoic shale for-mations, was considered the most likely area for aquifer recharge. This edge of the Mt. Simon aquifer also was investigated and characterized through observation well installations, water level monitoring, ground-water chemical analysis, and aquifer capacity testing to help determine recharge pathways and sustainable limits for this aquifer. These data will help determine aquifer recharge characteristics and potential limita-tions for future use.

Most data collected for this study are derived from well nests (two or more observation wells completed at the same location but at different depths) installed at 14 locations by contracted drilling companies. A total of 13 Mt. Simon Sandstone wells and 15 wells in other geologic units were drilled; one Mt. Simon sandstone well was sealed following drilling. Staff from the DNR Ecological and Water Resource Division coordinated the installation of these wells, which are known among groundwater professionals as observa-tion wells. Drilling in the northern portion of the investigation area (Phase 2) began in the fall of 2009 to complete well nests at an additional 10 locations. The wells are completed in the Mt. Simon aquifer and shallower aquifers on public property in the project area to depths of 70 feet to 718 feet (Table 1). The wells were sampled for chemical constituents such as tritium and carbon-14 that will help determine the residence time or age of the groundwater in this aquifer and overlying aquifers. The wells were also instru-mented with equipment to continuously record groundwater levels.


Geology of South-Central Minnesota

The focus of this investigation was the Cambrian Mt. Simon Sandstone (Figure 2) which is located at the base of a thick sequence of marine Paleozoic carbonate, shale, and sandstone formations that underlie central and southeastern Minnesota in a broad structural basin known as the Hollandale embayment (Figure 3). The Mt. Simon Sandstone is generally a medium to coarse-grained quartz-ose sandstone (Mossler, 2008). The Mt. Simon formation cuttings observed from drill holes for this project generally indicated the unit is dominated by thick beds of gray and white silty, very fine to medium-grained quartzose to feldspathic sandstones with thin white-grey and light green shale beds. The basal portion of the Mt. Simon Sandstone has somewhat thicker shale beds and coarse yellowish quartz grains ranging from very coarse sand to medium pebble size.

Various Precambrian rocks underlie the Mt. Simon Sandstone due to a complicated geologic history prior to the deposition of the Paleozoic rocks. These older underlying rocks include Middle Protero-zoic sedimentary rocks, such as the Hinckley Sandstone and the Fond du Lac Formation, Early Pro-terozoic igneous and metamorphic rocks, and in some southern areas, the Lower Proterozoic Sioux Quartzite. None of these underlying rocks have desirable aquifer properties for most purposes. There-fore, the Mt. Simon Sandstone is the deepest bedrock aquifer in the region. Furthermore, along the western edge of the Hollandale embayment (Figure 3), the Mt. Simon aquifer is commonly the only aquifer available for large capacity (i.e., municipal and industrial) use.

Following the deposition of sand and other sediments that would become the Mt. Simon Sandstone and overlying formations, there was a long period of exposure and non-deposition of rock materi-als. During the Late Cretaceous period marine and non-marine sedimentary rocks (mostly shale and sandstone) were deposited along the western edge of the Hollandale embayment in south-central Min-nesota. During this period a shallow epicontinental (inland) sea covered the western interior of North America. Relatively thick sections of these types are rocks are common in the southern portion of the investigation area.

Following another long period of exposure and non-deposition of rock materials after the Cretaceous period, the region was affected by repeated continental glaciations during the Quaternary period. These glaciations deposited thick alternating layers of glacial outwash (sand and gravel), glacial till (dense mixture of silt, sand, and clay), and other types of deposits. Thus the depositional history for most of southeastern and south-central Minnesota has left a legacy of both bedrock and glacial aquifer systems.


Investigation Methods

Site SelectionThe wells for this investigation were drilled on public land to help ensure the longevity of these moni-toring locations. With the exception of one location, all the wells are on state land managed by the Department of Natural Resources, on either wildlife management areas (WMAs) or at water access (WA) locations. One well site in Sibley County is owned by the county. At that location special access permission for that location was obtained from the County Board of Commissioners.

Site locations were chosen in suspected recharge areas for the Mt. Simon aquifer near the western edge of the Hollandale embayment at location where the Mt. Simon Sandstone was likely to be the uppermost bedrock to be found beneath the surficial glacial deposits or Cretaceous shale and sand-stone. A shallow and deep well were drilled at most locations to provide data on the vertical hydraulic head gradients, changes in groundwater chemistry, and residence time with depth. These sites were spaced as evenly as possible across the recharge area given the existing distribution of public land in the region. The well nest locations are typically near existing roads and parking lots for easy access and to minimize disturbance of undeveloped parts of these properties.

Drilling Methods and Well ConstructionTwo different kinds of drilling methods were used to install wells for this project (Table 1). Mud rotary (MR) is a commonly used and widely available method for drilling and completing water wells. Typically a hollow tricone drilling bit is attached to hollow drilling rods that are turned by the drilling rig. During the drilling process, a drilling mud mixture is pumped through the interior of the hollow rod and bit assembly which pushes the ground rock and sediment upward through the annular space between the drilling rods and the larger diameter borehole to the surface. The drilling mud flows into an open tank at the surface and is subsequently recirculated back down the inside of the drill bit/rod assembly to the bottom of the borehole. The advantage of this method is that it is relatively fast and inexpensive. The disadvantage of this method is that the ground-up bits of rock and sediment (also known as “cuttings”) that the driller and geologist use to identify drilling progress become difficult or impossible to identify below a depth of several hundred feet because of mixing and mechanical degra-dation of the cuttings on their way to the surface.

Another type of drilling method called dual rotary/ reverse circulation (DR/RC) was used in selected areas. During DR/RC drilling, the drill cuttings are returned to surface inside the rods. Reverse circu-lation is achieved by pumping air down the outer tube of the rods with a large compressor. The dif-ferential pressure at the drill bit creates suction that pulls the water and cuttings up the “inner tube” which is inside the rod. Once the water and cuttings reach the surface, the cuttings move through a sample hose and are collected in a sample pail. DR/RC drilling produces discrete and easily identifi-able rock chips from all depths and is therefore ideal for drilling in unknown areas where the geolo-gist does not know exactly what to expect at depth. DR/RC drilling is slower and more expensive than mud rotary.


Aquifer Interval Selection for MonitoringMethods for well construction were somewhat different for boreholes drilled with the two methods. For the dual rotary holes, an 8- inch or 10-inch diameter temporary steel surface casing was driven simultaneously during drilling to the base of the unconsolidated or poorly consolidated Quaternary and Cretaceous layers. Once solid bedrock was reached, the remainder of the hole was drilled with-out casing because the hole was unlikely to collapse. Drilling continued until Precambrian bedrock was encountered beneath the Mt. Simon Sandstone. A geophysical log of the hole was then made by geologists from the Minnesota Geological Survey at which time the depth of the permanent 4-inch diameter casing was determined based on the gamma log characteristics of the Mt. Simon Sandstone. The relatively shale-free portions of the formation were typically left as open hole. The casing was then constructed by the drilling crew and grouted in place and the temporary casing was removed. The advantage of this procedure was that the depth of the permanent casing could be chosen based on the cuttings and the geophysical log ensuring that the open-hole portion of the well was in the correct depth range such as the most transmissive portion of the Mt. Simon sandstone.

Drilling with the mud rotary method followed a different sequence. A seven-inch diameter borehole was drilled into the top of the Mt. Simon Sandstone and a four-inch steel casing was grouted in place. Once the grout had set, the drilling crew would drill inside the four-inch casing with a smaller drill bit and rod assembly until they had drilled through the Mt. Simon Sandstone into the underlying Pre-cambrian bedrock. The depth at which the Mt. Simon is encountered is estimated by reference to logs of nearby wells and careful observation of changes in the cuttings that come to the surface with the drilling mud. The main disadvantage of this method is that if the top of the Mt. Simon Sandstone is misidentified, the base of the permanent casing might not be placed at an ideal depth.

Once the deep Mt. Simon well aquifer was completed and logged with geophysical tools, the aquifer for the shallower well in the nest was chosen based on gamma log and cuttings characteristics. These shallow wells were completed in the discontinuous sand and sandstone layers of the Quaternary and Cretaceous units at a relatively wide range of depths. In general, we were seeking the shallowest aqui-fer that might be used for domestic or larger capacity purposes.

Geophysical Well LoggingWell logging is the practice of making a detailed record (a well log) of the geologic formations pen-etrated by a borehole. The geologic log is a compilation visual description and interpretations of samples brought to the surface. The geophysical well log is a record of formation physical properties with electrically powered instruments. The main geophysical log types collected for this project in-clude passive nuclear measurements (natural gamma rays) and resistivity. After the borehole has been completed, but before the permanent casing has been grouted in the borehole, the logging tool (or probe) is lowered into the open wellbore on a wire connected to the surface. Once lowered to the bot-tom of the hole, measurements are taken as the probe is withdrawn from the wellbore. Measurements are recorded continuously while the probe is moving.


Gamma ray logging is a method of measuring naturally occurring gamma radiation to characterize the rock or sediment in a borehole. Different types of rock emit different amounts and spectra of natural gamma radiation (Driscoll, 1986). Shale and clay usually emit more gamma rays than other sedimen-tary rocks, such as sandstone, or sand and gravel because radioactive potassium, uranium, and thorium are common components in their clay content. This difference in radioactivity between clay-rich and non-clay-rich formations allows the geologist to distinguish between shale and sandstone/carbonate rocks and fine or coarse grain glacial sediments with the natural gamma log.

Resistivity is a property of all materials which represents how strongly a material opposes the flow of electric current. This log is recorded in boreholes containing electrically conductive fluid (drilling mud or water). Sand and sandstone tend to be insulators (high resistivity); clay and shale tend to be conduc-tors (low resistivity). Similar to the gamma log, this difference in resistivity between shale (or clay-rich sediments) and sandstones/carbonate rocks (or non-clay-rich sediments) allows the geologist to distin-guish between the two general categories of sediments or sedimentary rocks using the resistivity log.

Generalized versions of the gamma logs completed by the staff of the Minnesota Geological Survey (MGS) are shown with the lithologic logs for each of the project well nests in Appendix A. The litho-logic descriptions on each of these logs are summarized from MGS interpretations of cuttings. De-tailed copies of these logs can be obtained from the MGS.

Well DevelopmentAfter the borehole is drilled and the permanent well casing is grouted in the well, the well is purged for one to two hours to remove sediment that may have accumulated at the base of the well. This well development procedure is designed to ensure that all or most of the open hole portion of the well is unclogged and water level measurements from the well are representative of water levels in the aquifer at that location.

Groundwater Sample CollectionProtocols commonly employed for the collection of groundwater samples generally require the re-moval of much of the standing water in the borehole prior to the collection of groundwater samples. This is done so that the sample represents fresh groundwater and is representative of the resource. Removing groundwater from a well can be completed through the use of many mechanical methods; including bailers, air injection and pumping. An electric submersible well pump was selected for this project because it is capable of removing hundreds of gallons of water from depths greater than 150 feet in a relatively short period of time time in preparation for groundwater sampling. In addition, well performance testing information was collected during the same field event. Therefore, the collection of water samples was organized to complete two tasks; the collection of groundwater samples and a short duration well performance test.

To accomplish these two tasks, a submersible water well pump was temporarily installed and operated by a State-certified water well contractor. An electric generator was used to provide power to the pump and a combination of piping and flexible hose were installed to deliver the groundwater to the surface. During the course of the field sampling events two different pumps were used. The first pump had a


capacity of eight gallons per minute which proved too low to pump out the required volumes of water at an acceptable rate. This pump was replaced by a pump capable of producing pumping rates of 25 gallons per minute. Table 2 presents the basic information collected during these procedures.

Groundwater was pumped through a hose from the flow meter to a clean, white five gallon bucket that allowed field observations of color and odor. The bucket was also used as a flow through chamber into which the probes of several instruments were suspended. Sequential measurements of temperature, pH and specific conductance were made. The wells were pumped until constant values of pH, temperature and specific conductance were observed. The groundwater sample was collected after the values of these parameters remained stable and at least one well volume of water had been removed from the well.

The sampling consisted of filling prepared and labeled containers with groundwater from the hose dis-charge at the stabilization bucket. The carbon-14 (14C) sample size was approximately 30 gallons and required special handling and containers. Analytes and sampling protocol are summarized in Table 3. Samples were sent to the University of Minnesota Hydrochemistry Laboratory (U of M) and the Uni-versity of Waterloo Laboratory (Waterloo).

Specific Capacity Procedures and Results A specific capacity test provides an estimate of the potential yield from a water well. Specific capacity can be calculated from the results of a short duration pumping test. Specific capacity is the pumping rate (gallons per minute) divided by the measured drawdown (feet) and is reported in units of gallons per minute per foot of drawdown (gpm/ft). In Minnesota’s principal aquifers, the observed specific capacities (Minnesota DNR, 2004) range from less than 1.0 gpm/ft. to values greater than 100 gpm/ft. Specific capacities for the Mt. Simon- Hinckley wells typically range from 1 to 33 gpm/ft; specific capacities for glacial drift wells show greater variability from less than 1 to greater than 50 gpm/ft. As shown in Table 2, the observed specific capacities for the Mt. Simon wells ranged from 13 gpm/ft at Exceder WMA to less than 1 gpm/ft at Helget-Braulick WMA.

The depths to groundwater were measured from dedicated measuring points located at the top of the well casings. For this project the measuring points elevations were measured using engineering grade global positioning systems (GPS) that use the Minnesota Department of Transportation Continuously Operating Reference Station (CORS) network. The measuring point at each well is on the north side of the top of the four-inch diameter steel well casing (top of casing or TOC). Groundwater depth measure-ments were collected before, during and after pumping using electronic tapes and electronic pressure transducer instruments.

A flow meter was used to measure rate and a flow totalizer was used to measure total water discharge in gallons. The flow rate from the well was controlled with the well head check valve. At the start of each pumping test the valve was opened to allow the full pumping rate. Some of the wells were pumped at rates lower than the capacity of the pump to maintain water levels above the pump intake. Graphs of changes in the water level and water temperatures over time (hydrographs) are included in Appendix B. DNR observation well 83012 and Flandrau State Park campground well were not accessible for water level instrumentation and are not represented in Appendix B with a hydrograph. These two wells were, however, sampled for groundwater chemical analysis.


Continuous Water Level MeasurementsUnattended continuous water level measurements can be made with pressure transducers – instru-ments that respond to changes in pressure created by the water column above the instrument. A data logger can record the measurements taken by a pressure transducer at specific intervals set by the user. Improvements in technology over the last decade have resulted in combined data logger and pressure transducer units that are about the size of a small flashlight.

Sealed data logger/pressure transducer units were submerged in each well to a depth of 20 to 25 feet below the water surface. Sealed units record changes in total pressure including barometric pressure. To discriminate changes in pressure readings that are related to barometric pressure change from real water level changes, a record of barometric pressure must also be made. Three data logger/barometer units were deployed across the study area for this purpose. All of the instruments were programmed to collect and store hourly readings.

Data are stored in the data logger until downloaded during quarterly site visit occurs. Communication cables connected to the instruments are accessible from the top of each well. At each location, the data are downloaded from the instruments, and a water level measurement is taken with a measuring tape. Following data downloads, computer software calibrates the data stream to the actual measurements and adjusts for changes in barometric pressure.

Thickness of the Mt. Simon Sandstone Near the Western Subcrop

One of the objectives of the project was to better define the physical boundaries of the Mt. Simon Sandstone in the study area to help with future water resource evaluations. With the exception of the well at the Nicollet Bay unit, all the Mt. Simon aquifer wells drilled for this project penetrated to the base of the formation. Most existing wells in this area (Figure 4) provide a minimum thickness value since most of the wells are domestic and are only drilled into the top of the aquifer to provide rela-tively small quantities of water.

Across the study area thicknesses of the Mt. Simon Sandstone increase toward the east over a short distance with the exception of an apparently broad and thin (0-50 feet) area in eastern Brown county. East of the western formation edge, the Mt. Simon Sandstone is commonly 200 feet thick or greater (Mossler, 1992).

Groundwater Movement and Potentiometric Surface – Mt. Simon Aquifer

A key aspect of understanding the hydrogeology of any area is to develop a basic understanding of the groundwater flow pathways. Aquifers and systems of aquifers are rarely static or unchangeable. Water is usually moving into the aquifers (recharge), through the aquifers, and out of the aquifers (discharge) in complicated but definable patterns. Three primary types of data are used by investigators to under-stand these relationships: chemical data from collected samples, aquifer test data gathered by pumping wells under controlled conditions, and static (non-pumping) data measured from wells and surface water bodies. Static water-level data and potentiometric surfaces are the primary focus of this section.


A potentiometric surface is defined as “a surface that represents the level to which water will rise in a tightly cased well (Fetter, 1988). The potentiometric surface of a confined aquifer (aquifer under pres-sure) occurs above the top of an aquifer where an overlying confining (low-permeability) layer exists. Static (non-pumping) water-level data from the County Well Index and measurements by personnel from the Department of Natural Resources were plotted and contoured to create the potentiometric contour map (Figure 5). Additional wells in fractured Precambrian crystalline aquifers beyond the extent of the Mt. Simon aquifer are included to show the hydraulic head conditions near the bound-ary of the aquifer. The contour lines illustrate the potentiometric surface much like the contour lines of a topographic map represent a visual model of the ground surface. The potentiometric surface is generally not the physical top of the water table, but is a representation of the potential energy that is available to move the groundwater in a confined aquifer. Low-elevation areas on the potentiometric surface that could be above the coincident surface-water bodies may indicate discharge areas; when combined with other information sources, high-elevation areas on the potentiometric surface can be identified as important recharge areas. Groundwater moves from higher to lower potentiometric eleva-tions perpendicular to the potentiometric elevation contours (flow directions shown as arrows).

Groundwater flow pathways from recharge areas through the aquifer to discharge locations operate on a wide continuum of depth, distance, and time. Flow into, through, and out of shallow aquifers can oc-cur relatively quickly in days or weeks over short distances of less than a mile, whereas flow through deeper aquifers across dozens of miles may take centuries or millennia.

Figure 5 shows northeasterly groundwater flow directions toward the Minnesota River in the south-ern portion of the study area. In the northern portion of the study area flow is southeasterly in Sibley County and then diverges toward the Minnesota River in Nicollet County at a very low gradient. On Figure 5 and Figure 6 (cross section Z-Z’) the potentiometric contours bend toward the Minnesota River indicating that it is a discharge feature for the Mt. Simon aquifer. Even though the potentiomet-ric contours indicate discharge to the Minnesota River, the previously mentioned low gradient in the northern portion of the study area could indicate low flow to the river.

Geochemistry

All the wells constructed for this project and two additional wells in the area were sampled for analy-sis of common ions, trace constituents, residence time indicators (tritium and 14C), and stable isotopes (18O and deuterium). The results of all these analyses (Tables 4 and 5) assist in the interpretation of the recharge characteristics of the Mt. Simon aquifer.

Groundwater Residence TimeTwo residence time indicators were used in this project: tritium and carbon-14 (14C). Residence time is the approximate time that has elapsed from when the water infiltrated the land surface to when it was pumped from the aquifer for these investigations. In general, short residence time suggests high recharge rates or short travel paths, whereas long residence time suggests low recharge rates or long travel paths.


Tritium (3H) is a naturally occurring isotope of hydrogen. Concentrations of this isotope in the atmo-sphere were greatly increased from 1953 through 1963 by above ground detonation of hydrogen bombs (Alexander and Alexander, 1989). This isotope decays at a known rate, with a half-life of 12.43 years. Groundwater samples with concentrations of tritium equal to or greater than 10 tritium units (TU) are considered recent water (mostly recharged in the past 60 years). Concentrations equal to or less than 1 TU are considered vintage water (recharged prior to 1953). Concentrations between these two limits are considered a mixture of recent and vintage water and are referred to as mixed water.

The carbon-14 (14C) isotope, which also occurs naturally, has a much longer half-life than tritium (5730 years). Carbon-14 is used to estimate groundwater residence in a time span from about 100 years to 40,000 years (Alexander and Alexander, 1989).

With one exception, none of the groundwater samples contained detectable tritium concentrations (Table 4) and therefore, the residence time for these samples is greater than approximately 60 years. This is con-sistent with the generally greater depths of the sampled aquifers and general lack of thick surficial sand and gravel in the study area. The one mixed tritium sample was from the shallow well at the Long Lake WA that was screened in a sand and gravel aquifer at a depth of 128 feet.

Figure 7 shows the distribution of 14C residence time values from the shallow wells constructed for this project. These values represent data from aquifers with a wide depth range (70 to 444 feet). This map, therefore, is not intended to show any regional trends or tendencies but is shown to illustrate the wide range of values in these settings. These values are more interesting in comparison to the values discussed below and shown in Figure 8 from the underlying Mt. Simon aquifer.

Figure 8 shows the distribution of 14C residence time values from the Mt. Simon aquifer wells con-structed for this project, two additional Mt. Simon aquifer wells sampled for this project, and Mt. Simon aquifer data from other studies (Lively and others, 1992; Alexander, personal communication). Values in the southern portion of the study area range from 7,000–8,000 years in central Watonwan County to 30,000 years near the Minnesota River following a pattern of increasing age away from central Waton-wan County. The youngest values (8,000–10,000 years) in the northern portion of the study area occur in northeastern Sibley County and also increase in age toward the Minnesota River to the south and east.

The younger 14C residence time values (7,000–8,000 years) roughly correspond to a time not only after the last ice sheet had receded from southern Minnesota, but also after the time when the modern day Minnesota River Valley (Glacial River Warren) ceased to be the main discharge route for the glacial melt water (9,500 years) that was stored in Glacial Lake Agassiz (Wright, 1987). These 14C values and the unique glacial history of the region suggest groundwater in the Mt. Simon aquifer in this region began as precipitation that infiltrated during the post-glacial period. The stable isotope data described in the fol-lowing section provided important corroborating evidence for this conclusion.

Stable Isotopes, 18O and DeuteriumAll groundwater samples collected from the study area were analyzed for stable isotopes of oxygen and hydrogen, the two atoms found in water. Analysis of the results provides an additional tool for character-izing the area groundwater. Isotopes of a particular element have the same number of protons but differ-ent numbers of neutrons. Stable isotopes are not involved in any natural radioactive decay. They are used to understand water sources or the processes affecting them (Kendall, 2003). Commonly used isotopes


for these purposes include oxygen isotopes 16O and 18O and hydrogen isotopes 1H and 2H. The heavy hydrogen (2H) is called deuterium. The mass differences between 16O and 18O or 1H and 2H result in water molecules that evaporate or condense at different rates. Thus the concentrations of these isotopes in water changes (fractionates) during evaporation and precipitation, resulting in different 16O/18O and 1H/2H ratios in rain, snow, rivers, and lakes. The values are expressed as del2H and del18O. The ab-breviation “del” denotes the relative difference from standard mean ocean water and express the rela-tive abundance or the rarer heavy isotopes, del2H and del18O. These values from precipitation water generally plot close to a straight line known as the meteoric water line (Figure 9). The departure of 18O and 2H values from the meteoric water line can indicate evaporation or mixing of water from different sources.

Figure 9 shows a plot of del18O and del2H values from groundwater samples collected in the study area compared to the meteoric water line. Three types of information regarding the origin and history of these water samples can be interpreted from this graph: relative atmospheric temperature during source water precipitation, relative mixing of water from cold and warm sources, and evaporation of source water.

Source Water Temperature and MixingFor the samples that plot along the same slope as the meteoric water line, the samples more depleted in heavy isotopes (samples that plot closer to the bottom left of the graph) suggest water that precipitated from a colder atmosphere (Siegel, 1989). Person et al (2007) provided a compilation of paleohydrologi-cal studies of groundwater systems in North America that were affected by the advance and retreat of the Laurentide ice sheet. He concluded that the range of del18O groundwater values from cold ice or snow melt sources ranges from del -25 to -9. Most values of groundwater samples from south central Minnesota ranged from approximately del -8 to del -10 suggesting a mixture of glacial meltwater and a larger component of post-glacial precipitation. The data are consistent with the younger 14C ages dates (7,000 to 8,000 years) from the post-glacial and post River Warren era as discussed previously.

It is also significant to note that many of the older 14C values in this area are in the range of the last glacial advance in the upper Midwest (12,000 to 24,000 years BP) but the del18O values are just slightly within the range of water from ice melt sources (del-25 to del-9). This apparent discrepancy suggests that these waters are from mixed sources and time periods, indicating a combination of much younger and much older water. Recognizing that all groundwater is a mixture, Mt. Simon 14C residence time values greater than 9,000 or 10,000 years may represent a minimum age in these areas.

Fractionation of Source Water and Evaporative SignaturesDeuterium (2H) is an isotope of hydrogen consisting of a proton and a neutron, whereas hydrogen (1H) consists of a proton. Deuterium, therefore, has approximately twice the mass of common hydrogen. Similarly, oxygen-18 (18O) has more mass than the more common oxygen-16 (16O). Fractionation occurs because of these mass differences. Molecules of water with the more common hydrogen and oxygen are lighter and more readily evaporated, leaving the remaining water more concentrated in the heavier isotopes. As a result, lake water typically shows an evaporative signature (a higher concentra-tion of the heavier isotopes than precipitation). Water that directly infiltrates the ground is not fraction-ated in this manner, so it has a meteoric signature (higher concentration of the lighter, more prevalent isotopes). The effect of this type of fractionation is that isotopic values from samples with an evapora-tive signature will plot along a line with a slope less than the slope of the meteoric water line.


On Figure 9 the evaporated types of samples are shown on the right upper portion of the graph (Peter-son unit, Helget Braulick WMA, and the Nicollet Bay unit). These three samples, from buried sand and gravel aquifers, show evidence of water that infiltrated from lakes or wetlands.

The majority of samples plotted in the center portion of the graph along the meteoric water line (Figure 9) suggest sources from post ice-age precipitation (normal rain and snow meltwater) that infiltrated directly into the subsurface and did not reside for long periods in lakes or similar water bodies.

Major IonsSome evidence of distinct source water types and mixing of these waters can be understood by con-sidering the relative abundances of some common cations and anions as ion concentrations plotted as percentages from area groundwater samples. Figure 10 shows the relative abundances of these common ions plotted on a ternary plot. Table 5 also shows the concentrations of these constituents in mg/l. The most common type of water in this area has Ca and Mg (Ca+Mg) as the predominant cation. There is a fairly even distribution between waters containing bicarbonate as the primary anion and waters contain-ing sulfate as the predominant anion. The bicarbonate type of water is common in glacial aquifers of the upper Midwest (Freeze and Cherry, 1979, p. 284) and is derived from dissolution of calcite and dolomite minerals in soil and glacial sediments by infiltrating precipitation. Higher sulfate concentra-tions in the Mt. Simon aquifer tend to occur in the southern and western portions of the study area (Fig-ure 11) where infiltrating water has passed through Cretaceous sandstone and shale layers that contain sulfate minerals such as gypsum and anhydrite.

The data from a few samples plotted on the lower right corner of the cation ternary plot show that some Na/K waters are also present in the area. These Na/K type waters (Mt. Simon aquifer: Norwegian Grove and Flandreau; Sioux Quartzite: Courtland West) may have a partial deep bedrock origin. Other evidence of deep isolated groundwater or upwelling from deep crystalline bedrock sources is suggested by some elevated chloride values of samples collected near the Minnesota River Valley (Figure 12). El-evated chloride values at the Helget Braulick and Peterson unit sites should be dismissed since samples from these wells probably contain some chloride from the chloride disinfectant that was added to these wells during the well construction process.

Trace ElementsAnalysis of groundwater samples for a suite of trace element constituents reveal exceedences of drink-ing water standards for boron (one sample) and arsenic (five samples). A boron concentration of 1,910 ug/l (ppb) was measured in water from the Lake Hanska well that was completed in a Cretaceous sand-stone aquifer. The Minnesota Department of Health (MDH) health risk limit (HRL) for this element is 600 ug/l. This elevated value is not typical of concentrations measured in the rest of the samples which otherwise ranged from 74 to 497 ug/l (Table 4). The reason for the elevated concentration of boron is unknown; however, the most negative 18O value (del -10.27) of all the samples collected in the study area was also detected in the sample from this well which suggests that this aquifer is relatively stag-nant and isolated.

Arsenic concentrations that exceeded the federal drinking water standard of 10 ug/l were detected in samples collected from five wells, three from buried sand and gravel aquifers and two from the Mt. Simon aquifer (Table 4 and Figure 13). Two of the exceedences (Nicollet Bay unit and Helget-Braulick WMA) from buried sand and gravel aquifers also contained water from sources with an evaporative


surface water signature (discussed in the fractionation of source water section). Arsenic in groundwa-ter tends to come from disseminated mineral sources in glacial till (MDH, 2001; Erickson and Barnes, 2005). Arsenic can be released from these minerals into solution by oxygenated water. Infiltrated lake water could be a possible source of oxygenated water resulting in the elevated arsenic concentrations found in these samples.

Two of the elevated arsenic samples were collected from the Mt. Simon aquifer wells at the Peterson unit and the Nicollet Bay unit. Both of these wells are near Swan Lake in Nicollet County, the ap-parent source of water with an evaporative signature sampled at the shallow Nicollet Bay unit well. Elevated arsenic values in the Mt. Simon aquifer may be also due to mobilization of arsenic by oxy-genated lake water that has infiltrated through multiple interconnected layers of glacial sand and till.

Hydrogeology Illustrated by Cross Sections and Hydrographs from Observation Well Nests

A set of 12 geologic cross sections were created for this report to provide location-specific represen-tations of the stratigraphy and geologic structure for each well nest and to provide a hydrogeologic context for the hydrograph and geochemical data. The cross sections were constructed by projecting lithologic, stratigraphic, and well construction information onto the line of each cross section (Figure 3) from within a one kilometer zone on either side of the cross section.

Water level data were plotted to create hydrographs illustrating water elevation changes over time. Hydrographs provide a method of representing large amounts of data from one or more wells. The water elevation hydrographs are provided for each corresponding cross section. Each hydrograph dis-plays the water levels recorded in two wells nested at the same site, the Mt. Simon aquifer well (blue) and the shallower depth well (red). Nested wells are located at the same site within a few feet of each other. On several hydrographs the difference in water elevation is large enough to require the use of a secondary axis. The shallower well information is set on the secondary axis and the corresponding units are indicated on the right side of the hydrograph.

Seasonal high and low water level cycles are apparent on most hydrographs. These are yearly cycles where groundwater levels decline during the summer months and increase during the winter and spring. In many cases both nested wells follow similar trends. Average cumulative precipitation in-creased throughout the period of record for the water level data (Figure 14). A corresponding rise of water levels throughout 2010 is apparent from the hydrographs at several sites and is consistent with the cumulative increases in rainfall for the region compared to normal. Considering the relatively long residence times typical of most aquifers that were sampled for this study most of these water level fluctuations are not caused by rapid infiltration of precipitation (recharge) but a pressure response to the increased volume and weight of additional groundwater in the overlying water table aquifer and shallow buried aquifers (Maliva et al, 2011).


The hydrograph data of the nested observation wells, shown on Figures 15b through 26b, show two general patterns of vertical gradients: downward and upward. Most of the hydrograph comparisons show a downward gradient. A downward gradient exists where the groundwater elevation in the shal-lower well is higher than the groundwater elevation in the deeper well. This condition indicates that groundwater will move downward, if a flow pathway is available. Within this group of downward gradient hydrograph pairs most of the hydrographs follow identical although offset patterns (Sibley County Landfill, Peterson Unit, Bergdahl WMA, Case WMA, Madelia WMA, Exceder WMA, and Rooney Run WMA). These identical patterns strongly suggest that fluctuations within both the shallow and Mt. Simon aquifer well pairs are due to pressure effects of changes in the overlying water weight of the water table aquifer. A smaller group of downward gradient nests (Severance Lake WMA, Nicol-let Bay Unit, and Helget Braulick WMA) show shallow aquifer hydrograph patterns that are different from the Mt. Simon aquifer hydrograph pattern suggesting local pumping or surficial influences in the shallow aquifer.

The Courtland West Unit (Figure 19b), Long Lake WA (Figure 24b), and possibly Norwegian Grove WMA (Figure 17b) sites demonstrate locations where upward groundwater movement is apparently oc-curring. At these locations the groundwater elevation from the shallower well is lower than the deeper bedrock groundwater elevations indicating an upward gradient condition. An upward gradient suggests that groundwater from the deeper bedrock will move upward if a flow pathway is available. Upward gradient maybe due to local pumping influences or proximity to major discharge zones such as the Minnesota River.

Cross Section A-A’ and Severence Lake WMA Hydrograph (Figures 15a and b) The Severence Lake WMA is located in northern Sibley County near the subcrop (eastern edge) of the Mt. Simon Sandstone. The shallow well was completed in a buried sand and gravel aquifer that appears to be part of a stack of interspersed and hydraulically connected sand bodies. The hydrograph from this well shows several feet of variation throughout 2010 with low water levels occurring during summer and early fall (high water use period). Water levels recovered beginning late fall and continued through early spring. A similar but more muted pattern is apparent for the Mt. Simon aquifer, suggesting no connection or a very minor connection to the summer pumping that is occurring in the area.

Cross Section B-B’ and Sibley County Landfill Property (Figures 16a and b)The well nest on the Sibley County landfill property in central Sibley County is located near the City of Gaylord. The Gaylord city wells and some domestic wells completed in the same buried sand aquifer as the shallow well are shown northwest of the well nest. The stratigraphy and geochemistry shown on Cross section B-B’ (Figure 16a) suggest a direct hydraulic connection between the buried sand and gravel aquifer in which the shallow well is completed and the Mt. Simon aquifer. The well nest hy-drographs (Figure 16b) show a downward gradient from the buried sand and gravel aquifer. The area stratigraphy, long residence times, and identical water level hydrograph trends suggest that the water level fluctuations are a pressure response to changes in the weight of water in the overlying water table aquifer. Cross Section C-C’ and Norwegian Grove WMA Hydrograph (Figures 17a and b) The Norwegian Grove WMA well nest in northern Nicollet County is located at the eastern edge of the Mt. Simon subcrop. The cross section (Figure 17a) shows the shallow well is completed in a stack of interspersed, and hydraulically connected sand bodies and a nearly direct connection of these buried


sand aquifers to the underlying Mt. Simon aquifer. The hydrographs (Figure 17b) shows a very slight upward gradient from the Mt. Simon to the buried sand and gravel aquifer. The hydraulic connec-tion between the two aquifers, however, may not be very extensive since there is a large difference in groundwater residence time (4,000 years in the shallow aquifer versus 20,000 years in the Mt. Simon aquifer) and aquifer chloride/sodium concentrations.

Cross Section D-D’ and Peterson Unit Hydrograph (Figures 18a and b) The Peterson Unit well nest in central Nicollet County is located near the eastern edge of the Mt. Simon Sandstone subcrop. The aquifer hydrographs (Figure 18a) shows very little fluctuation in water levels (approximately one foot). The buried sand aquifer water levels are about eight feet higher than those of the Mt. Simon aquifer. These water level data and the 14C residence time of 22,000 year of the Mt. Simon aquifer suggest that these aquifers are not directly connected and are both relatively iso-lated.

Cross Section E-E’ and Courtland West/Nicollet Bay unit hydrographs (Figures 19a, b and c) The geologic setting of two well nests (Courtland West unit and Nicollet Bay unit) in south cen-tral Nicollet County and an existing well that was sampled (Flandreau State Park) in eastern Brown County, is shown on this cross section. An upward gradient exists at the Courtland West site, east of the Minnesota River, which may result in upward groundwater flow direction due to the proximity of the river. Upward gradients are commonly found near major rivers where groundwater discharges to the al-luvial aquifer from underlying aquifers locally. West of the Minnesota River a similar upward gradient is suggested by a 14C residence time of 30,000 years and high sodium-chloride concentrations (Table 5 and Figure 12). These chemical characteristics suggest old, isolated groundwater from the underlying crystalline bedrock is moving upward through the thin Mt. Simon aquifer to the base of the Minnesota River alluvium.

At the Nicollet Bay unit location at the east side of the cross section the shallow well is shown complet-ed in a stacked complex of buried sand and gravel aquifers. The graph of stable isotope values (Figure 9) shows that the sample from this well contains some water that had an evaporative signature from a surface water source. The detectable tritium concentration from this sample is also good evidence of focused recharge at this location. The relatively constant water level elevation shown in the hydrograph from this well (Figure 19c) and these chemical characteristics suggest a strong hydraulic connection to a stable surface water source such as Swan Lake. The hydrograph of the Mt. Simon aquifer well at this location appears to show some influence from local pumping possibly from the wells shown on the cross section west of the Nicollet Bay well nest.

Cross Section F-F’ and Helget-Braulick WMA hydrograph (Figures 20a and b) The Helget-Braulick WMA well nest is located in central Brown County near the western edge of the Mt. Simon Sandstone subcrop. The shallow well, completed in a buried sand and gravel aquifer, contained some groundwater tht had an evaporative signature from a surface water source (Figure 9). A very short 14C residence value (500 years) is consistent with this stable isotope data. In addition, the shallow well hydrograph trend follows the precipitation trend of higher than average rainfall during the summer of 2010, also suggesting a hydraulic connection and pressure response to the additional water at or near the surface. The muted but similar hydrograph pattern of the Mt. Simon aquifer well hydro-graph is probably a pressure response.


Cross Section G-G’ and Bergdahl WMA hydrograph (Figure 21a and b) The Bergdahl WMA well nest of northeastern Watonwan County and a shallower well completed in Cretaceous sandstone at the SE Lake Hanska WA are shown on this cross section. The deeper well that was planned for the Lake Hanska site was not built since no Mt. Simon Sandstone was found at this site during drilling. Both hydrographs in the Bergdahl WMA well nest show for 2010 a rising pressure response corresponding to a cumulative increase in precipitation in the area.

Cross Section H-H’ and Case WMA hydrograph (Figures 22a and b) The Case WMA well nest located in eastern Watonwan County and an irrigation well that was sampled for this project are shown on this cross section. Some of the youngest Mt. Simon aquifer groundwa-ter in the area was collected from the irrigation well which is located at the eastern edge of the Mt. Simon Sandstone subcrop. The 14C residence time of 7,000 years from this well is actually younger than groundwater that was sampled from the shallower buried sand and gravel aquifer at the Case WMA well nest. This irrigation well sample also contained elevated concentrations of sulfate indicat-ing migration through the overlying sulfate mineral rich Cretaceous sandstone and shale. Both hydro-graphs at the Case WMA well nest show an approximate 4.5 foot pressure response rise in water levels throughout 2010 which corresponds to a cumulative increase in precipitation in the area.

Cross Section I-I’ and Madelia WMA hydrograph (Figures 23a and b) The Madelia WMA well nest located in eastern Watonwan County is shown on the eastern side of this cross section. The Mt. Simon aquifer sample from this location also had one of the youngest 14C resi-dence time values, suggesting a closer proximity to the eastern edge of the Mt. Simon sandstone sub-crop than is suggested by this cross section or Figure 4. Both hydrographs at the Madelia WMA well nest show an approximate 4.5 foot pressure response rise in water levels throughout 2010 correspond-ing to a cumulative increase in precipitation in the area.

Cross Section J-J’ and Long Lake WA hydrograph (Figures 24a and b) The Long Lake WA well nest located in south central Watonwan County is shown on the western side of this cross section possibly near the center of the Mt. Simon Sandstone subcrop. Similar to the sites described on cross sections H-H’ and I-I’, the 14C residence time value of the Mt. Simon aquifer at this location is among the youngest (8,000 years). Elevated sulfate concentrations indicate groundwater migration through the overlying Cretaceous sandstone and shale.

The shallow well was completed in a buried sand and gravel aquifer just above the Cretaceous sand-stone and shale. The gradient between the shallow aquifer and the Mt. Simon aquifer is upward (lower hydraulic head in the shallow aquifer compared to the deeper aquifer) possibly due to intensive pump-ing of the shallow buried aquifers from domestic wells surrounding Long Lake. The approximate 1.5 to 2.5 foot rise of water levels in both wells throughout 2010 corresponds to a cumulative increase in precipitation in the area.

Cross Section K-K’ and Exceder WMA hydrograph (Figures 25a and b) The Exceder WMA well nest, located in north central Martin County, is shown near the center of this cross section. The approximate two-foot pressure response rise of water levels in both wells throughout 2010 corresponds to a cumulative increase in precipitation in the area.


Cross Section L-L’ and Rooney Run WMA hydrograph (Figures 26a and b)The bedrock geology of the Rooney Run area is relatively unknown. The top of the Mt. Simon Sand-stone at the DNR observation well site was deeper than the top of the Mt. Simon Sandstone at wells drilled in the Welcome area (Figure 26a). Therefore, a fault is shown on cross section L-L’ northwest of Welcome to account for this elevation difference. Southwick (2002) also shows a fault in this area described as an “Inferred fault, mapped beneath the Sioux Quartzite or Paleozoic strata.” The hydro-graphs of the buried sand and gravel and Mt. Simon wells show very little fluctuation during 2010 and are difficult to interpret without a longer period of record.

Paleohydrology and Recharge Estimates

Data and interpretations generated by this project provide some basis for a general estimate of ground-water recharge through overlying glacial sediments and Cretaceous formations to the Mt. Simon Sand-stone subcrop in south central Minnesota. In addition to improving understanding of the aquifer bound-aries, thickness, permeability, and extent of overlying confining units, basic data have been generated regarding the residence time of groundwater in the Mt. Simon aquifer and its source water characteristics.

The 7,000-8,000 year residence time of Mt. Simon aquifer groundwater in the region (see Figure 27, Watonwan County and adjoining areas and northern Sibley County near the City of Arlington) and development of post-glacial drainage conditions in the Minnesota River Valley at approximately 9,000 years BP (before present) suggests the current flow conditions toward the valley and slow recharge of the aquifer began at approximately that time. Prior to that time the much larger volume of water flowing through the valley as glacial River Warren would have created higher head conditions in that area and a lower gradient that would have inhibited flow toward the valley in the Mt. Simon and over-lying aquifers. Siegel (1989) suggests that flow in the Mt. Simon aquifer during the glacial maximum (16,000-14,000 years BP) was easterly toward the ancestral Mississippi River.

A conceptual model of recharge to the Mt. Simon subcrop is based on geochemical data shown on the generalized cross section Z-Z’ (Figure 28) which extends from the Long Lake WA site in southwestern Watonwan County to the North Star WMA observation well in the Minnesota River Valley. This cross section is drawn perpendicular to the potentiometric contours of the Mt. Simon aquifer (Figure 8) and is meant to represent a flow path from the recharge areas southwest of the Minnesota River to the Min-nesota discharge area.

On cross section Z-Z’ 14C residence times are younger in areas to the southwest in the Mt. Simon aqui-fer and overlying aquifers. Higher sulfate concentrations in the Mt. Simon aquifer in the southwest in-dicate downward groundwater flow through the overlying Cretaceous formations. Slightly higher chlo-ride concentrations have been detected in wells closer to the discharge area suggesting some upward migration of older water from Precambrian crystalline bedrock. Finally, the least negative (warmer) del 18O values are found in Mt. Simon wells on the left portion (upgradient) of the cross section and in the shallower wells, whereas the more negative del 18O values (colder) were found in wells on the right (downgradient) portion of the cross section.


Southern Area RechargeA conceptual recharge model based on this information is shown in Figure 29. The groundwater resi-dence times of most of the Mt. Simon wells are assumed to be an average value of age-stratified water in the well. Actual values from discrete intervals within the wells might vary from top to bottom. There-fore, an assumed 5,000 year value contour was placed near the top of the Mt. Simon aquifer for the wells in the “post-glacial recharge” area. The depth to the top of this contour in this area ranges from approximately 350 to 450 feet. Assuming an average depth of 400 feet (12,192 cm), an average porosity of the material overlying the Mt. Simon at 20 %, the amount of recharge moving downward to the top of the Mt. Simon aquifer would be approximately 0.49 cm/year. The area labeled “post-glacial recharge” (Figure 27) is approximately 960 square km. The volume of recharge across this area would be approxi-mately 4.7 million cubic meters/year or about 1.2 billion gallons/year.

Northern Area RechargeA similar recharge estimate of the Mt. Simon aquifer for the eastern portions of Nicollet and Sibley Counties (area north and west of the Minnesota River) is more difficult since only a small portion of the area west of the City of Arlington and the Severance Lake WMA is shown as post-glacial recharge (Figure 27). In most of this area 14C residence time values are approximately three times older than the youngest values southwest of the Minnesota River. In general, groundwater recharge of the Mt. Simon in the northern portion of this region (north and west of the Minnesota River) is probably lower than in the southern part of this region (south of the Minnesota River).

2009 Groundwater Appropriation

Southern Area AppropriationFor this appropriation discussion the southern area is defined as a triangular area that extends from the southernmost well nest (Rooney Run WMA) to Mankato and along the Minnesota River to New Ulm (Figure 30). Mt. Simon aquifer groundwater in the southern area is currently used by permitted (large capacity) municipal wells, agricultural processing wells, and irrigation wells (DNR web page). The DNR 2009 reported use data indicate approximately 2.2 billion gallons were pumped out of the Mt. Simon aquifer in this area. However, the actual volume pumped from just the Mt. Simon aquifer is less since some of the older municipal wells in the area are also open to overlying aquifers. The Mt. Simon aquifer annual pumped volume, therefore, may be more than the recharge described in the previous sec-tion. Permitted volumes (volume of water that the users are allowed to pump) for appropriators in this area are approximately 4.7 billion gallons per year.

Northern Area AppropriationThe northern area is defined as the eastern parts of Nicollet and Sibley Counties. Mt. Simon ground-water in the northern area is currently used by permitted (large capacity) municipal wells, agricultural processing wells, and crop irrigation wells, and golf course irrigation wells (DNR web page). The DNR 2009 reported use data indicate approximately 1.1 billion gallons were pumped out of the Mt. Simon aquifer in this area. As in the southern area, the actual volume pumped from just the Mt. Simon aquifer is less since some of the older municipal wells in the area are also open to overlying aquifers. Permitted volumes for appropriators in this area are approximately 1.9 billion gallons per year.


Conclusions

The results of this project suggest that Mt. Simon aquifer groundwater use in the study area, for the most recent period (2009), may be more than the replacement rate along the Mt. Simon Sandstone subcrop. Continued monitoring of the observation wells in this region should help determine if more water is being used compared to recharge. A major accomplishment of this project is the creation of a network of observation well nests along the western margin of the Mt. Simon Sandstone that is considered an important recharge area for the aquifer. Long term water level and geochemistry data from these wells will enable future hydrologists to evaluate the local and regional effects of Mt. Simon aquifer groundwater pumping in the region. In addition, this project demonstrated the value of continuous, nested water level measurements, groundwater chemistry, and residence time data in constructing conceptual models of groundwater flow and recharge.


References

Alexander, S.C., and Alexander, E.C., Jr., 1989, Residence times of Minnesota groundwaters: Minnesota Academy of Sciences Journal, v. 55, no.1, p. 48-52.

Alexander, S.C., personal communication, e-mail correspondence received May 26, 2009 containing 14C and general chemistry information from wells in southeastern Minnesota.

Anderson, Julia R, 2010, Bedrock geology, Plate 2 of Geologic Atlas in Blue Earth County, Minnesota: Minnesota Geological Survey County Geologic Atlas C-26 (in progress), scale 1:100,000.

Chandler, Val. W. and Mossler, John H., 2009, Bedrock Geology, Plate 2 of Geologic Atlas in Mcleod County, Minnesota: Minnesota Geological Survey County Geologic Atlas Geologic Atlas of McLeod County, C-20, 6 pls., scale 1:100,000.

Driscoll, Fletcher G., 1986, Groundwater and wells (2d ed.): St. Paul, Minnesota, Johnson Screens, 1089 p.

Erickson, M.L., and Barnes, R.J., 2005, Glacial sediment causing regional-scale elevated arsenic in drinking water: Ground Water, November-December, v. 43, no. 6, p. 796–805.

Fetter, C.W., 1988, Applied hydrogeology (2d ed.): Columbus, Ohio, Merrill, 592 p.

Freeze, R. Allan, and Cherry, John A., 1979, Groundwater, Englewood Cliffs, NJ, Prentice Hall, Inc., 604 p.

Jirsa, Mark A. and others, 2011, Geologic Map of Minnesota Bedrock Geology, Minnesota Geological Survey State Map Series S-21, scale 1:500,000.

Kendall, C. and Doctor, D., 2003, Stable isotope applications in Hydrologic studies, Holland, H.D. and Turekian, K.K., editors, chap. 11 of v. 5, Surface and ground water, weathering, and soils, in Treatise on geochemistry: Amsterdam, The Netherlands, Elsevier, Inc., p. 319-364.

Lively, Richard S. et al, 1992, Radium in the Mt. Simon-Hinckley aquifer, east-central and southeastern Minnesota, Information Circular 36, Minnesota Geological Survey, 58 p.

Maliva, Robert G. et al, 2011, Confined aquifer loading: Implications for groundwater management, Groundwater, May-June 2011, vol. 49, No. 3, p. 302-304.

Minnesota Department of Health, 2001, Minnesota arsenic study (MARS): St. Paul, Minnesota Department of Health, 3 p.

Minnesota Department of Natural Resources, 2004, Selected aquifer parameters for groundwater provinces – Groundwater Provinces web page, accessed at < http://www.dnr.state.mn.us/groundwater/ provinces/data.html>.

Minnesota Department of Natural Resources, Water use – Water Appropriations Permit Program web page, accessed at <http://www.dnr.state.mn.us/waters/watermgmt_section/appropriations/wateruse.html>.


Mossler, J.H., 1992, Sedimentary rocks of Dresbachian age (Late Cambrian), Hollandale embayment, southeastern Minnesota: Minnesota Geological Survey Report of Investigations 40, 71 p.

Mossler, J.H., 2008, Paleozoic stratigraphic nomenclature for Minnesota: Minnesota Geological Survey Report of Investigations 65, 76 p., 1 pl.

Mossler, J.H., and V.W. Chandler, 2009, Bedrock geology, Plate 2 in Geologic Atlas of Carver County, Minnesota: Minnesota Geological Survey County Atlas C-21, 5 pls., scale 1:100,000.

Mossler, J.H., and V.W. Chandler, 2010, Bedrock geology, Plate 2 in Geologic Atlas of Sibley County, Minnesota: Minnesota Geological Survey County Geologic Atlas C-24 (in progress).

Mossler, J.H., and V.W. Chandler, 2010, Bedrock geology, Plate 2 in Geologic Atlas of Nicollet County, Minnesota: Minnesota Geological Survey County Geologic Atlas C-25 (in progress).

Person, M., J. McIntosh, V. Bense, and V. H. Remenda, 2007, Pleistocene hydrology of North America: The role of ice sheets in reorganizing groundwater flow systems, Rev. Geophys., 45, RG3007, doi:10. 1029/2006RG000206.

Siegel, D.I., 1989, Geochemistry of the Cambrian-Ordovician aquifer system in the northern Midwest, United States: U.S. Geological Survey Professional Paper 1405-D, 76 p.

Southwick, D.L., 2002, M-121 Geologic map of pre-Cretaceous bedrock in southwest Minnesota. Minnesota Geological Survey map series M-121, scale 1:250,000

Wright, H. E., 1987, Quaternary History of Minnesota in Geology of Minnesota, Minnesota Geological Survey, University of Minnesota, St. Paul, Minnesota p. 515-548.


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toO

B#

Uni

que

Cou

nty

Site

Nam

eFo

rmat

ion

Met

hod

Dep

thEa

stin

gN

orth

ing

(ft a

bove

msl

)(ft

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ve m

sl)

inte

rval

(ft)

wat

er (f

t)

5200

176

8263

Nic

olle

tN

icol

let B

ayC

MTS

DR

/RC

519

4009

38.2

0349

0280

7.50

399

0.66

998

8.37

041

0-51

915

7.07

5200

276

8264

Nic

olle

tN

icol

let B

ayQ

BA

AM

R19

840

0936

.287

4902

804.

578

990.

761

988.

448

188-

198

145.

6052

003

7682

61N

icol

let

Cou

rtlan

d W

est

PM

SX

DR

/RC

463

3920

95.6

1649

0556

5.04

799

6.32

199

2.73

035

6-46

310

8.87

5200

476

8262

Nic

olle

tC

ourtl

and

Wes

tQ

BA

AM

R20

239

2095

.445

4905

567.

941

994.

935

992.

493

195-

205

108.

2152

005

7704

49N

icol

let

Pet

erso

nC

MTS

DR

/RC

545

3979

39.2

449

1111

0.02

499

3.46

799

1.33

339

0-54

516

3.92

5200

677

0450

Nic

olle

tP

eter

son

QB

AA

MR

223

3979

37.8

5249

1110

6.35

993.

752

991.

497

215-

223

156.

1252

007

7704

44N

icol

let

Nor

weg

ian

Gro

veC

MTS

DR

/RC

537

4056

53.7

1749

2301

8.88

598

1.18

897

8.37

839

0-53

715

2.71

5200

877

0445

Nic

olle

tN

orw

egia

n G

rove

QB

AA

MR

260

4056

55.5

6449

2301

5.73

598

0.87

697

8.34

924

5-25

315

2.37

0801

276

8259

Bro

wn

Heg

et B

raul

ick

CM

TSD

R/R

C28

236

9435

.816

4896

564.

649

1021

.947

1019

.757

267-

282

40.1

008

013

7682

60B

row

nH

eget

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ulic

kQ

BA

AR

S70

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9438

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4896

564.

977

1021

.900

1019

.371

65.5

-70.

526

.23

seal

ed76

0651

Bro

wn

Lake

Han

ska

CM

TSM

R31

637

4745

.213

4885

215.

946

1004

.311

1004

.161

seal

edse

aled

0801

476

0692

Bro

wn

Lake

Han

ska

KR

ET

MR

164

3747

43.7

3848

8521

8.59

910

09.4

1410

03.5

8215

5-16

43.

5283

017

7606

87W

aton

wan

Cas

eC

MTS

MR

672

3894

50.7

748

7199

1.53

310

41.9

2210

38.8

0349

5-67

255

.30

8301

876

0686

Wat

onw

anC

ase

QB

AA

MR

206

3894

53.6

8248

7198

9.96

910

41.9

6710

39.1

6019

7-20

638

.62

8301

976

0689

Wat

onw

anM

adel

iaC

MTS

MR

648

3821

01.0

4848

7009

3.55

510

67.0

1110

63.8

4249

5-64

848

.65

8302

076

0688

Wat

onw

anM

adel

iaK

RE

TM

R12

038

2101

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4870

090.

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1067

.303

1064

.408

109-

119

28.1

083

021

7606

91W

aton

wan

Ber

gdah

lC

MTS

MR

479

3885

08.6

9948

8326

7.00

299

9.80

299

6.85

741

5-47

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.31

8302

276

0690

Wat

onw

anB

ergd

ahl

QB

AA

MR

129

3885

04.0

7448

8326

7.28

010

02.7

5710

00.7

1211

9-12

936

.67

8302

377

0427

Wat

onw

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ng L

ake

CM

TSD

R/R

C54

736

5169

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4862

854.

602

1131

.407

1129

.111

373-

547

32.6

983

024

7704

39W

aton

wan

Long

Lak

eQ

BA

AM

R12

836

5174

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4862

852.

802

1131

.731

1129

.249

118-

128

32.5

946

006

7681

25M

artin

Exc

eder

C

MTS

MR

680

3726

99.8

5948

5131

8.45

011

76.8

5611

74.0

1549

7-68

075

.24

4600

776

8139

Mar

tinE

xced

er

KR

ET

MR

232

3727

00.1

5948

5132

2.78

711

76.9

6611

74.0

8622

2-23

281

.95

4600

877

1163

Mar

tinR

oone

y R

unC

MTS

MR

718

3667

04.5

2248

4343

1.03

012

03.8

7312

01.2

3664

0-71

869

.06

4600

977

1161

Mar

tinR

oone

y R

unQ

BA

AM

R44

436

6705

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4843

427.

544

1204

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1201

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434-

444

68.1

272

000

7704

40S

ible

yS

ible

y C

o. L

FC

MTS

MR

*57

540

5883

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4932

926.

374

995.

742

993.

624

460-

575

126.

9072

001

7704

41S

ible

yS

ible

y C

o. L

FQ

BA

AM

R43

040

5888

.095

4932

926.

352

996.

049

993.

974

420-

430

126.

7372

002

7704

42S

ible

yS

ever

ance

Lak

eC

MTS

DR

/RC

630

4106

98.7

8949

4736

9.75

610

10.6

4810

08.5

2945

8-63

014

4.23

7200

377

0443

Sib

ley

Sev

eran

ce L

ake

QB

AA

DR

/RC

280

4106

96.3

1749

4736

9.95

510

09.9

7710

08.1

8227

2-28

088

.32

Dril

ling

met

hods

:M

R =

mud

rota

ryQ

BA

A =

Qua

tern

ary

burie

d aq

uife

rC

MTS

= C

ambr

ian

Mt.

Sim

on s

ands

tone

DR

/RC

= d

ual r

otar

y/re

vers

e ci

rcul

atio

nK

RE

T =

Cre

tace

ous

sand

ston

eP

MS

X =

Pre

cam

bria

n S

ioux

qua

rtzite


Tabl

e 2

- Spe

cific

Cap

acity

and

Wat

er L

evel

Dat

a Su

mm

ary

Dep

th to

Stat

icst

atic

wat

erw

ater

Pu

mpe

dAv

erag

eW

ater

leve

lSp

ecifi

cD

ate

M

Nfr

om to

pel

evat

ion

Pum

ping

volu

me

pum

ping

dr

awdo

wn

capa

city

sam

pled

uniq

ueC

ount

ySi

te n

ame

Form

atio

nca

sing

(ft)

(ft a

bove

msl

)(m

inut

es)

(gal

lons

)ra

te (g

pm)

(feet

)(g

pm/d

raw

dow

n)

10/7

/200

977

0442

Sib

ley

Sev

eran

ce L

ake

CM

TS14

4.18

866.

468

156

1240

8.0

1.22

6.5

10/7

/200

977

0443

Sib

ley

Sev

eran

ce L

ake

QB

AA

88.7

892

1.19

778

620

7.9

0.86

9.2

10/8

/200

977

0440

Sib

ley

Sib

ley

Co.

LF

CM

TS12

6.95

868.

792

114

970

8.5

1.69

5.0

10/8

/200

977

0441

Sib

ley

Sib

ley

Co.

LF

QB

AA

126.

7486

9.30

970

590

8.4

0.30

28.0

10/8

/200

977

0444

Nic

olle

tN

orw

egia

n G

rove

CM

TS15

2.38

828.

808

107

880

8.2

1.18

7.0

10/9

/200

977

0445

Nic

olle

tN

orw

egia

n G

rove

QB

AA

152.

2582

8.62

644

310

7.1

0.88

8.0

10/9

/200

977

0449

Nic

olle

tP

eter

son

CM

TS16

3.69

829.

777

120

834

7.0

1.22

5.7

10/9

/200

977

0450

Nic

olle

tP

eter

son

QB

AA

155.

9483

7.81

240

326

8.2

2.66

3.1

10/1

3/20

0976

8261

Nic

olle

tC

ourtl

and

Wes

tP

MS

X10

9.65

886.

670

9012

61.

418

6.25

0.00

7510

/9/2

009

7682

62N

icol

let

Cou

rtlan

d W

est

QB

AA

108.

5788

6.36

539

320

8.1

0.69

11.8

10/1

4/20

0976

8263

Nic

olle

tN

icol

let B

ayC

MTS

157.

7383

2.94

057

1200

21.2

8.27

2.6

10/1

4/20

0976

8264

Nic

olle

tN

icol

let B

ayQ

BA

A14

6.52

844.

240

1325

020

4.8

4.2

10/1

4/20

0976

8259

Bro

wn

Heg

et B

raul

ick

CM

TS40

.71

981.

237

103

230

263

0.03

610

/14/

2009

7682

60B

row

nH

eget

Bra

ulic

kQ

BA

A25

.95

995.

950

2933

711

.732

.00.

367

10/1

5/20

0976

0691

Wat

onw

anB

ergd

ahl

CM

TS42

.03

957.

770

3694

426

22.8

1.1

10/1

4/20

0976

0690

Wat

onw

anB

ergd

ahl

QB

AA

38.4

596

4.30

720

536

2690

.20.

310

/15/

2009

7606

87W

aton

wan

Cas

eC

MTS

57.2

098

4.72

240

1040

264.

75.

510

/15/

2009

7606

86W

aton

wan

Cas

eQ

BA

A40

.10

1001

.867

3893

025

8.7

2.8

10/1

5/20

0976

0689

Wat

onw

anM

adel

iaC

MTS

50.4

310

16.5

8162

1610

267.

23.

610

/15/

2009

7606

88W

aton

wan

Mad

elia

KR

ET

29.4

010

37.9

0323

627

275.

35.

110

/15/

2009

7704

27W

aton

wan

Long

Lak

eC

MTS

32.4

910

98.9

1774

1887

263.

86.

710

/15/

2009

7704

39W

aton

wan

Long

Lak

eQ

BA

A32

.70

1099

.031

2358

625

11.3

2.2

10/1

6/20

0976

8125

Mar

tinE

xced

er

CM

TS76

.38

1100

.476

6415

0323

1.8

13.1

10/1

6/20

0976

8139

Mar

tinE

xced

er

KR

ET

63.2

011

13.7

6648

967

2016

.71.

210

/26/

2009

7711

63M

artin

Roo

ney

Run

CM

TS69

.06

1134

.813

6510

7017

12.5

1.3

10/2

6/20

0977

1161

Mar

tinR

oone

y R

unQ

BA

A68

.12

1136

.197

5312

7024

12.6

1.9

10/2

8/20

0976

0692

Bro

wn

Lake

Han

ska

KR

ET

4.33

1005

.084

5717

13

0.6

4.8

11/2

4/20

0913

2275

Wat

onw

an83

012

CM

TS8.

8910

25.8

716

1440

090

0na

na10

/26/

2009

4053

38B

row

nFl

andr

au S

PC

MTS

nana

150

450

3na

na

QB

AA

= Q

uate

rnar

y bu

ried

aqui

fer

CM

TS =

Cam

bria

n M

t. S

imon

san

dsto

ne

KR

ET

= C

reta

ceou

s sa

ndst

one

PM

SX

= P

reca

mbr

ian

Sio

ux q

uartz

ite


Tabl

e 3

Fie

ld S

ampl

e C

olle

ctio

n an

d H

andl

ing

Det

ails

Para

met

erLa

bSa

mpl

e co

ntai

ner

Hea

d sp

ace

Rin

seFi

lter

Pres

erva

tive

Ref

riger

atio

nSh

elf l

ifeFi

eld

dupl

icat

eFi

eld

blan

kSt

orag

e du

plic

ate

Triti

umW

ater

loo

500

ml,

HD

PEye

sN

Ono

nono

long

1 fo

r eve

ry 2

0no

neye

s

18O

, D

eute

rium

Wat

erlo

o60

ml,

HD

PEye

sN

Ono

nono

long

1 fo

r eve

ry 2

0no

neye

s

Cat

ions

U o

f M15

ml,

Fish

erbr

and

BLU

E ca

p

yes

yes

*ye

s1

drop

6N

HC

lye

s2-

3 w

eeks

1 fo

r eve

ry 2

01

for e

very

20

****

no

Anio

nsU

of M

50 m

l, Ar

gos

BLAC

K **

*

yes

yes

*ye

sno

yes

2-3

wee

ks1

for e

very

20

1 fo

r eve

ry 2

0 **

**no

Trac

e co

nstit

uent

sU

of M

15 m

l, Sa

rste

dt

RED

cap

yes

yes

*ye

s5

drop

s

15N

HN

O3

yes

2-3

wee

ks1

for e

very

20

1 fo

r eve

ry 2

0 **

**no

Alka

linity

onsi

te50

0 m

l, pl

astic

NO

yes

**no

noYe

s, if

not

an

alyz

ed

onsi

te

24-4

8 ho

urs

none

none

no

14C

U o

f M30

gal

lon

barr

elye

sno

yes

NH

4OH

to p

H

8.5

noye

ars

none

none

no

* R

inse

the

bottl

e on

ce w

ith F

ILTE

RE

D s

ampl

e w

ater

prio

r to

colle

ctin

g th

e sa

mpl

e. R

insi

ng m

eans

fill

the

bottl

e w

ith s

ampl

e w

ater

(FIL

TER

ED

if s

ampl

e is

filte

red)

and

then

pou

r the

con

tent

s ou

t ove

r the

cap

.

***

Fill

50 m

l ani

on b

ottle

unl

ess

filte

ring

is v

ery

diffi

cult.

Bot

tle m

ust b

e at

leas

t 1/3

full.

****

Use

DI w

ater

from

sm

all b

ottle

for f

ield

bla

nks

(NO

T TH

E C

AR

BO

Y).

Pou

r DI w

ater

into

the

back

of t

he s

yrin

ge w

hen

the

plun

ger i

s re

mov

ed. F

ill b

ottle

s th

roug

h fil

ter.

** R

inse

the

bottl

e th

ree

times

with

sam

ple

wat

er p

rior t

o co

llect

ing

the

sam

ple.

Fill

bot

tle s

ubm

erge

d w

ith c

ap in

han

d. S

eal b

ottle

sub

mer

ged

ensu

ring

no re

mna

nt b

ubbl

es.


Tabl

e 4

Res

iden

ce ti

me

indi

cato

rs, s

tabl

e is

otop

es, a

nd s

elec

ted

trac

e el

emen

ts

Trac

e el

emen

ts**

Res

iden

ce ti

me

indi

cato

rsSt

able

isot

opes

****

MN

uni

que

Site

nam

eC

ount

yFo

rmat

ion

Dep

th (f

t)D

ate

sam

pled

AsB

14C

(yea

rs)

Triti

um**

*D

eute

rium

18O

0040

5338

Flan

drau

Sta

te P

ark

Brow

nC

MTS

200

10/2

6/20

090.

1989

30,0

00<0

.8-6

8.61

-9.9

500

7606

92La

ke H

ansk

a W

MA

Brow

nKr

et16

410

/28/

2009

0.13

1910

11,0

00<0

.8-6

8.69

-10.

2700

7682

59H

elge

t-Bra

ulic

k W

MA

Brow

nC

MTS

284

10/1

4/20

090.

2936

113

,000

<0.8

-63.

42-8

.56

0076

8260

Hel

get-B

raul

ick

WM

ABr

own

QBA

A70

.510

/14/

2009

41.2

376

500

<0.8

-50.

23-6

.39

0076

8125

Exce

der W

MA

Mar

tinC

MTS

680

10/1

6/20

090.

3717

313

,000

<0.8

-69.

97-9

.85

0076

8139

Exce

der W

MA

Mar

tinKR

ET23

110

/16/

2009

0.44

272

11,0

00<0

.8-6

5.92

-9.1

100

7711

61R

oone

y R

un W

MA

Mar

tinQ

BAA

444

10/2

6/20

093.

7833

58,

000

<0.8

-66.

69-9

.88

0077

1163

Roo

ney

Run

WM

AM

artin

CM

TS71

810

/26/

2009

0.61

193

10,0

00<0

.8-6

9.42

-9.7

000

7682

61C

ourtl

and

Wes

t Uni

t*N

icol

let

PMSX

463

10/9

/200

90.

2357

1N

A<0

.8-7

2.7

-9.8

100

7682

62C

ourtl

and

Wes

t Uni

t*N

icol

let

QBA

A20

210

/9/2

009

1.45

742,

300

<0.8

-54.

04-7

.72

0076

8263

Nic

olle

t Bay

Uni

t*N

icol

let

CM

TS47

410

/14/

2009

44.2

152

18,0

00<0

.8-6

5.90

-9.6

600

7682

64N

icol

let B

ay U

nit*

Nic

olle

tQ

BAA

198

10/1

4/20

0914

.311

4R

ecen

t<0

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8


Figures


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!P

!P

!P

!P

Isanti

Anoka

Hennepin

Martin

Brown

Jackson

Nicollet

Watonwan

Wright

Sibley

McLeod

Sherburne

Mankato

St. Paul

St. Cloud

Minneapolis

Figure 1Mt. Simon observation well nest locations

well nest location

Phase 1 area(funded 2008)

Phase 2 area(funded 2009)

Regional west boundaries

Mt. Simon Sandstone

Eau Claire Formation (shale)


Figure 2 Cambrian and older stratigraphy in study area (Modified from Mossler 2008)


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#

#

Cmu

Cu

Omu

Cmu

Case WMA

Madelia WMA

Exceder WMA

Long Lake WA

SE Hanska WA

Bergdahl WMA

Peterson unit

Rooney Run WMA

Nicollet Bay unit

Sibley Co property

Severence Lake WMA

Norwegian Grove WMA

Courtland West unit

Helget-Braulick WMA

irrigation

Flandreau State Park

Cmu

Clr

Csl

Oo

Cj

Cm

Clr

Ce

Cj

Os

Cj

Csl

Phf

Clr

Cw

Cj

Osp

Cj

Cm

Csl

CwOs

Op

Csl

Ps

Ce

Csl

Op

Os

Os

Cj

Ol

Os

Cw

Omu

Cw

Ce

Op

Csl

Ol

Clr

Op

Ce

Cm

Cm

Oo

Ou

Csl

Ol

Cu

I

J

E

H

F

A

KL

G

D

C

B

I'

J'

E'

H'

F'

K'

L'

G'

D'

C'

Brown

Sibley

Martin

Renville

Nicollet

Blue Earth

Watonwan

Faribault

McLeod

Jackson

Redwood

Cottonwood

Le Sueur

Carver

Scott

St. Peter Sandstone, Osp

Prairie du Chien Group, Op and Oo

Jordan Sandstone, Cj

St. Lawrence Fm, Csl

Tunnel City Gp (Lone Rock Fm), Clr

Wonewoc Sandstone, Cw

Eau Claire Fm, Ce

Mt. Simon Sandstone, Cm

County Atlas unitsPaleozoic bedrock

Precambrian bedrock

Hinckley Sandstoneand/or Fond du Lac Formation, Phf

Sioux Quartzite, Ps

State map units

Upper Cambrian, Cu(includes Cj, Csl, and Clr)

Lower Ordovician, Ol(includes Op and Oo)

Middle and Upper Cambrian, Cmu(includes Cm, Ce, and Cw)

Upper Ordovician, OuMiddle and Upper Ordovician, Omu

Paleozoic bedrock

Figure 3County and state Paleozoic bedrock map

Regional west boundary Ce(dashed where uncertain)Regional west boundary Cm(dashed where uncertain)

! New well nests for this project

# Existing water supply wells

Samples wells

Study area location in Hollandaleembayment (modified from Siegel 1989)


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150

200

50

100

50

50

100

I

J

E

H

F

K

A

L

G

D

C

B

I'

J'

E'

H'

F'

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L'

G'

D'

C'

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Brown

Sibley

Martin

Blue Earth

Nicollet

Renville

Faribault

Watonwan

Jackson

Redwood

McLeod

Cottonwood

Le Sueur

Carver

Scott

Figure 4Mt. Simon Sandstone thickness

Mt. Simon wells

Existing water supply wells

! New well nests for this project

!

Contour interval = 50 feet

Regional west boundary Cm


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Z

Z'

825

850

800

900

950

1100

1000

1150

1050

1200

850

900

850

Sibley

Martin

Brown

Blue Earth

Nicollet

Faribault

Renville

Watonwan

Le Sueur

McLeod

Jackson

Redwood

Cottonwood

Carver

Scott

Waseca

Regional west boundary Ce


Figure 5Mt. Simon potentiometric surfaceand groundwater flow directions

Mt. Simon potentiometric surface contours

50 feet

25 feet

Mt. Simon groundwater flow directions


Und

iffer

entia

ted

Cre

tace

ous

sand

ston

ean

d sh

ale

glac

ial s

edim

ents

(in

terb

edde

d sa

nd,

clay

, and

silt

)

Mt.

Sim

on

Sand

ston

e

Eau

Cla

ire F

m

Tunn

el C

ity g

roup W

onew

oc S

s

Prec

ambr

ian

crys

talin

e be

droc

k(ig

neou

s an

d m

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orph

ic)

Long

Lak

e W

A w

ell n

est

City

of S

t. Ja

mes

Irrig

atio

n w

ells

City

of M

edal

ia*

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gdah

l WM

A w

ell n

est

Nor

th S

tar

WM

A ob

serv

artio

nw

ell

Minnesota River Valley

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sur

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5000280QBAA

2600121QBAA

50070.5QBAA

4000253QBAA

8000223QBAA

2300205QBAA

8000129QBAA

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18000438QBAA

11000164KRET

9000206QBAA

Brown

Sibley

Blue Earth

Nicollet

Martin

Watonwan

Figure 7Carbon-14 residence time data from the shallower aquifers at each observationwell nest

Estimated residencetime in years (carbon-14)

10001 - 25000

25001 - 60000

33 - 100

101 - 1000

1001 - 10000

8000 (residence time, years)206 (well depth, feet)QBAA (aquifer code)




Z

Z'

Brown

Sibley

Blue Earth

Martin

Nicollet

Watonwan

825

850

800

900

950

1100

1000

1150

1050

1200

850

900

850

7000

7000

8000

10000

13000

10000

10000

17000

20000

13000

20000

22000

18000

30000

8000

30000

20000

30000

20000

20000

20000

* With addtional data from Richard Lively (MGS), Scott Alexander and Calvin Alexander (U of M)

Figure 8Mt. Simon carbon-14 residence time,potentiometric surface and groundwaterflow directions

-9.85 - delta 18O value

Estimated residencetime in years (carbon-14)*

10001 - 25000

25001 - 60000

33 - 100

101 - 1000

1001 - 10000




-90

-80

-70

-60

-50

-40

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agnesium (M

g)

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te (S

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hlor

ide

(Cl)

+ Ni

trate

(NO

3)

Aquifer

Figure 10Ternary diagram - relative abundances of major cations and anions

" CMTS - Cambrian Mt. Simon sandstone

! PMSX - Precambrian Sioux quartzite

# QBAA - Quaternary buried aquifer

KRET - Cretaceous sandstone"


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Blue Earth

Martin

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239

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475

586

191

162

181

175

45.1

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328

150151

96.7

36.1

Figure 11Mt. Simon sulfate concentrations (mg/l), and groundwater flow directions




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1.21

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2.67

21.4

7.04

3.59

1.49

11.2

60.9

18.0

130.9

34.6*

48.7*

Figure 12Mt. Simon chloride concentrations (mg/l) and groundwater flow directions

* Samples appear to contain added chloride from well construction disinfectants




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Brown

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Martin

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Watonwan

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0.37

0.37

1.88

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1.67

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1.93

22.8

44.2

Figure 13Mt. Simon arsenic concentrations (ug/l) and groundwater flow directions




Figure 14 Precipitation departure from normal October 2009 – September 2010


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523

1.75

9,00

0-9

.07

320

1.83

00666239

00666237

00624247

0013

2275

0076

0686

0076

0687

Wel

l cas

ing

Wel

l scr

een

or o

pen

hole

00760692

Uni

que

num

ber (

CW

I)

7000

(14

C re

side

nce

time,

yea

rs)

-9.1

5 (d

elta

18O

, * m

eans

sam

ple

cont

ains

som

e ev

apor

ated

wat

er fr

om a

sur

face

wat

er s

ourc

e)58

4

(Sul

fate

mg/

l - p

pm)

2.3

(C

l mg/

l - p

pm)

Figu

re 2

2aC

ross

sec

tion

H-H

'


Figu

re 2

2b

Cas

e W

MA

H

ydro

grap

h


!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

!

!

!!

!

!!

!

!!

!

!

!!

!!

!

!

I

I'

Mt.

Sim

on S

s

Eau

Cla

ire F

mWon

ewoc

Ss

Tunn

el C

ity G

p

Pre

cam

bria

n cr

ysta

lline

rock

Cre

tace

ous

shal

e an

d sa

ndst

one*

St.

Jam

esM

adel

ia W

MA

5000

feet

Verti

cal e

xagg

erat

ion

= 50

X


glac

ial

sedi

men

ts (t

ill)

glac

ial s

and/

grav

el

950

900

850

800

750

700

650

600

550

500

450

400

350

1100

1050

1000

7,00

0-9

.18

388

0.99

4,00

0-9

.04

99.1

0.56

00215100

00215096

00188670

00707359

00128481

00213571

00160494

00213570

00734614

00215098

00215099

00682252

00215089

00160532

0076

0688

0076

0689

Wel

l cas

ing

Wel

l scr

een

or o

pen

hole

00760692

Uni

que

num

ber (

CW

I)

7000

(14

C re

side

nce

time,

yea

rs)

-9.1

5 (d

elta

18O

, * m

eans

sam

ple

cont

ains

som

e ev

apor

ated

wat

er fr

om a

sur

face

wat

er s

ourc

e)58

4

(Sul

fate

mg/

l - p

pm)

2.3

(C

l mg/

l - p

pm)

Figu

re 2

3aC

ross

sec

tion

I-I'


Figu

re 2

3b

Mad

elia

WM

A

Hyd

rogr

aph


!

!

!

!!

!

!

!

!!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

!

!

!

!

!!

!

!

!

!

!!

!

J

J'

Mt.

Sim

on S

s

Eau

Cla

ire F

m

Won

ewoc

Ss

Tunn

el C

ity G

p

Pre

cam

bria

n cr

ysta

lline

rock

Cre

tace

ous

shal

e an

d sa

ndst

one*

Long

Lak

e W

MA

Lew

isvi

lle

5000

feet

Verti

cal e

xagg

erat

ion

= 50

X


glac

ial

sedi

men

ts (t

ill)

glac

ial s

and/

grav

el

950

900

850

800

750

700

650

600

550

500

450

1200

1150

1100

1050

1000

8,00

0-8

.64

1114

1.492,60

0 -8

.31

665

7.77

00145274

00160522

00653534

0077

0427

0077

0439

0021507700575842

Wel

l cas

ing

Wel

l scr

een

or o

pen

hole

00760692

Uni

que

num

ber (

CW

I)

7000

(14

C re

side

nce

time,

yea

rs)

-9.1

5 (d

elta

18O

, * m

eans

sam

ple

cont

ains

som

e ev

apor

ated

wat

er fr

om a

sur

face

wat

er s

ourc

e)58

4

(Sul

fate

mg/

l - p

pm)

2.3

(C

l mg/

l - p

pm)

Figu

re 2

4aC

ross

sec

tion

J-J'


Figu

re 2

4b

Long

Lak

e W

A

Hyd

rogr

aph


!

!

!

!

!

!!

!

!

!

!

!

!

!

!

!

!

!

!

!!!

!

!

!

!

!

!

!

!

!

!

!

!

K

K'

Mt.

Sim

on S

s

Eau

Cla

ire F

m

Won

ewoc

Ss

Tunn

el C

ity G

p

Pre

cam

bria

n cr

ysta

lline

rock

Cre

tace

ous

shal

e an

d sa

ndst

one*

Exce

der W

MA

Trum

an

5000

feet

Verti

cal e

xagg

erat

ion

= 50

X


glac

ial

sedi

men

ts (t

ill)

glac

ial s

and/

grav

el

950

900

850

800

750

700

650

600

550

500

450

1250

1200

1150

1100

1050

1000

13,0

00

-9.8

549

3 2.

67

11,0

00-9

.11

435

2.25

00228454

00121411

00450855

00132949

00171925

0076

8139

0076

8125

Wel

l cas

ing

Wel

l scr

een

or o

pen

hole

00760692

Uni

que

num

ber (

CW

I)

7000

(14

C re

side

nce

time,

yea

rs)

-9.1

5 (d

elta

18O

, * m

eans

sam

ple

cont

ains

som

e ev

apor

ated

wat

er fr

om a

sur

face

wat

er s

ourc

e)58

4

(Sul

fate

mg/

l - p

pm)

2.3

(C

l mg/

l - p

pm)

Figu

re 2

5aC

ross

sec

tion

K-K

'


Figu

re 2

5b

Exce

der W

MA

H

ydro

grap

h


!

!!

!

!

!

!

!!

!

!

!

!

!

!

!

!!

!

!

!

!

!

!

!

!

!

!

!!!

!

LL'

Mt.

Sim

on S

sEau

Cla

ire F

mW

onew

oc S

s

Pre

cam

bria

n cr

ysta

lline

rock

Cre

tace

ous

shal

e an

d sa

ndst

one*

Roo

ney

Run

WM

ATr

imon

tW

elco

me

5000

feet

Verti

cal e

xagg

erat

ion

= 50

X


glac

ial

sedi

men

ts (t

ill)

glac

ial s

and/

grav

el95

0

900

850

800

750

700

650

600

550

500

450

400

350

1200

1150

1100

1050

1000

10,0

00

-9.7

047

5 7.

04

8,00

0 -9

.88

615

2.10

00740631

00760954

00121387

00751616

00217088

00723690

00199654

00107187

00217109

00128456

0077

1161

0077

1163

00731340

00744078

00121333

Wel

l cas

ing

Wel

l scr

een

or o

pen

hole

00760692

Uni

que

num

ber (

CW

I)

7000

(14

C re

side

nce

time,

yea

rs)

-9.1

5 (d

elta

18O

, * m

eans

sam

ple

cont

ains

som

e ev

apor

ated

wat

er fr

om a

sur

face

wat

er s

ourc

e)58

4

(Sul

fate

mg/

l - p

pm)

2.3

(C

l mg/

l - p

pm)

Figu

re 2

6aC

ross

sec

tion

L-L'


Figu

re 2

6b

Roo

ney

Run

WM

A

Hyd

rogr

aph


Z

Z'

Brown

Sibley

Blue Earth

Martin

Nicollet

Watonwan

8000

30000

20000

30000

20000

20000

20000

7000-9.15

7000-9.18

8000-8.64

10000-9.36

13000-9.85

10000-9.28

10000-9.70

17000-9.75

20000-9.39

13000-8.56

20000-9.59

22000-8.23

18000-9.66

30000

Figure 27Mt. Simon recharge interpretation

Mixedpost-glacial rechargeand olderwater

Post-glacial recharge

Mt. Simon groundwater flow directions

-9.85 - delta 18O value

Estimated residencetime in years (carbon-14)

10001 - 25000

25001 - 60000

33 - 100

101 - 1000

1001 - 10000



Post-glacial recharge


Und

iffer

entia

ted

Cre

tace

ous

sand

ston

ean

d sh

ale

glac

ial s

edim

ents

(in

terb

edde

d sa

nd,

clay

, and

silt

)

Mt.

Sim

on

Sand

ston

e

Eau

Cla

ire F

m

Tunn

el C

ity g

roup W

onew

oc S

s

Prec

ambr

ian

crys

talin

e be

droc

k(ig

neou

s an

d m

etam

orph

ic)

Long

Lak

e W

A w

ell n

est

City

of S

t. Ja

mes

Irrig

atio

n w

ells

City

of M

edal

ia*

Ber

gdah

l WM

A w

ell n

est

Nor

th S

tar

WM

A ob

serv

artio

nw

ell


8,00

0 yr

s1,

114

mg/

l sul

fate

1 m

g/l C

l-8

.64

del 1

8O7,

000

yrs

751

mg/

l sul

fate

1 m

g/l C

l-9

.15

del 1

8O10

,000

yrs

*52

3 m

g/l s

ulfa

te2

mg/

l Cl

-9.3

6 de

l 18O

20,0

00 y

rs58

6 m

g/l s

ulfa

te11

mg/

l Cl

-9.3

9 de

l 18O

30,0

00 y

rs97

mg/

l sul

fate

28 m

g/l C

l

*Cas

e W

MA

wel

l dat

a pr

ojec

ted

Mt.

Sim

on a

quife

r pot

entio

met

ric s

urfa

ce8,

000

yrs

544

mg/

l sul

fate

2 m

g/l C

l-9

.19

del 1

8O9,

000

yrs*

320

mg/

l sul

fate

2 m

g/l C

l-9

.07

del 1

8O

2,60

0 yr

s66

5 m

g/l s

ulfa

te8

mg/

l Cl

-8.3

1 de

l 18O

Z

Z'

Figu

re 2

8G

ener

aliz

ed c

ross

sec

tion

Z-Z'

and

sel

ecte

dge

oche

mic

al d

ata


Mt.

Sim

on

Sand

ston

eEa

u C

laire

Fm

Tunn

el C

ity g

roup Won

ewoc

Ss

Prec

ambr

ian

crys

talin

e be

droc

k(ig

neou

s an

d m

etam

orph

ic)

Long

Lak

e W

A w

ell n

est

City

of S

t. Ja

mes

Irrig

atio

n w

ells

City

of M

edal

ia*

Ber

gdah

l WM

A w

ell n

est

Nor

th S

tar

WM

A ob

serv

artio

nw

ell


*Cas

e W

MA

wel

l dat

a pr

ojec

ted

glac

ial s

edim

ents

(in

terb

edde

d sa

nd,

clay

, and

silt

)U

ndiff

eren

tiate

d C

reta

ceou

s sa

ndst

one

and

shal

e

5,00

0 ye

ars

2,50

0 ye

ars

10,000 years

20,000 years

30,00

0 years

Z

Z'

Figu

re 2

9 C

ross

sec

tion

Z-Z'

M

t. S

imon

rech

arge

and

dis

char

ge

Post

-gla

cial

rech

arge

mix

ed p

ost-g

laci

al a

nd o

lder


!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

!

!

Fairmont

Mankato

Victoria

New Ulm

Saint Peter

Le Sueur

Jackson

Windom

Olivia

Waconia

Belle P la ine

Nor th Mankato

Redwood F alls

Glencoe

Blue Ear th

Courtland

Hector

Sanborn

Wel ls

Evan

Mapleton

Winnebago

Madel ia

Gaylord

Fair fax

Saint James

Morton

Springfie ld

Sleepy Eye

Kasota

Arl ington

Le C enter

Mayer

Trum an

Bird Island

Lafayette

Easton

Eagle Lake

Minnesota Lake

Cobden

Delavan

Cologne

Nicol let

Lake Crysta l

Winthrop

Elysian

Janesvil le

Stew ar t

Trimont

Sherburn

Henderson

Franklin

Mounta in Lake

Welcom e

Gibbon

Ceylon

Frost

Odin

Danube

Green Isle

NorwoodYoung America

Morgan

Plato

Granada

Kiester

Cleveland

Darfur

Buffa lo Lake

Saint Cla ir

Bingham Lake

Lester Pra irie

Waldorf

Com frey

New Germany

Ormsby

Good Thunder

Butterfie ld

Amboy

Brownton

Clem ents

New Auburn

Dunnell

Bricelyn

Alpha

Madison Lake

Wal ters

Vernon C enter

Hanska

Lewisville

Skyline

Ham burg

Pemberton

Nor throp

Biscay

La Salle

Case WMA

Madelia WMA

Exceder WMA

Long Lake WA

SE Hanska WA

Bergdahl WMA

Peterson unit

Rooney Run WMA

Nicollet Bay unit

Sibley Co property

Severence Lake WMA

Norwegian Grove WMA

Courtland West unit

Helget-Braulick WMA

J'

E'

H'

F'

A'

K'

L'

G'

D'

C'

B'

I

J

E

H

F

A

KL

G

D

C

BSibley

Brown

Martin

Blue Earth

Nicollet

Renville

Faribault

Watonwan

McLeod

Le Sueur

Jackson

Redwood

Carver

Cottonwood

Scott

Waseca

Groundwater appropriation 2009 (million gallons/year)

Mt. Simon and combinations

Unconsolidatedsand and gravel

well nest location

Regional west boundaries

Mt. Simon Sandstone

Eau Claire Formation (shale)

0.0 - 20.0

20.1 - 40.0

40.1 - 60.0

60.1 - 80.0

80.1 - 100.0

100.1 - 857.5

0.0 - 20.0

20.1 - 40.0

40.1 - 60.0

60.1 - 80.0

80.1 - 100.0

100.1 - 1370.1

Figure 30Mt. Simon observation well nestlocations and 2009 groundwater appropriation(millions of gallons/year)


Appendix A


Lithologic Description Lithologic Symbol

Geological Log Legend

Top Soil

Till

Lake Deposit

Outwash

Sandstone

Sandstoneand shale

Shale

Quartzite

Igneous ormetamorphic

bedrock

Geological Log Legend


Site Name

County

ElevationDepth Lithology Gamma0 250

MN Unique

Nested Well Construction

Geological / Geophysical Logs and Well Construction Diagrams

1000

900

800

700

600

500

400

0

100

200

300

400

500

600

Severance Lake WMA

Sibley

770443770442

Topsoil

Till (multiple sources withoutwash)

Outwash

Till (multiple sources withoutwash)

Outwash - Undifferentiated

Lake deposit

Eau Claire Formation

Mount Simon Sandstone

Hinckley Sandstone

Grout

Waterlevel

4 Inchcasing

Wellscreen

Grout

Waterlevel

4 InchCasing

OpenHole


Site Name

County


MN Unique



1200

1100

1000

900

800

700

600

500

0

100

200

300

400

500

600

700

Rooney Run WMA

Martin

771161771163

Topsoil

Till - New Ulm Formation

Outwash (NW source)

Till (NW source)

Lake deposits (NW source)

Till (NW source)

Lake deposits -undifferentiated

Outwash (NE Rainy source)

Wonewoc Sandstone (UpperCambrian)

Eau Claire Formation (Middleto Upper Cambrian)

Mount Simon Sandstone(Middle Cambrian)

Pre-Mount Simon saprolith(?)

Granitic rock? (Neoarchean)

Grout

Waterlevel

4-inchcasing

WellScreen

Grout

Waterlevel

4 inchcasing

Openhole


Site Name

County


MN Unique



900

800

700

600

500

0

100

200

300

400

500

Swan Lake WMA Peterson Unit

Nicollet

770450770449

Topsoil

Till - Des Moines Lobe (highshale member)

Outwash - Des Moines Lobe(moderate shale member)

Till - Des Moines Lobe(moderate shale member)

Outwash

Unnamed formation (Lowerto Upper Cretaceous, Albianto Cenomanian)


Mt. Simon sandstone

Unnamed granite/gneiss(Archean)

Grout

4-inchcasing

Waterlevel

Wellscreen

Grout

Waterlevel

4 inchcasing

Openhole


Site Name

County


MN Unique



900

800

700

600

500

0

100

200

300

400

500

Norwegian Grove WMA

Nicollet

770445770444

Topsoil


Outwash - Traverse desSioux Formation (Rainy lobe)

Till - Traverse des SiouxFormation (Rainy lobe)

Outwash - Traverse desSioux

Till - Traverse des Sioux

Outwash (NW source)

Till (NW source)

Outwash (NW source)

Lake deposits

Outwash (NW source)

Lake deposits - Undiff.



Mt. Simon sandstone

Fond du Lac Formation

Grout

4-inchcasing

Waterlevel

Wellscreen

Grout

Waterlevel

10inchcasing

4 inchcasing

Openhole


Site Name

County


MN Unique



900

800

700

600

500

0

100

200

300

400

500

Swan Lake WMA - Nicollet Bay Unit

Nicollet

768264768263

Topsoil

Till - Des Moines Lobe

Outwash - Des Moines Lobe


Outwash (NW source)

Lake Deposits -Undifferentiated

Wonewoc Sandstone



Grout

4-inchcasing

Waterlevel

Wellscreen

Grout

8 inchcasing

Waterlevel

4 inchcasing

Openhole

Stabilizerpack


Site Name

County


MN Unique



1000

900

800

700

600

500

0

100

200

300

400

500

600

Madelia WMA

Watonwan

760688760689

Top soil

Lake Deposits - Glacial LakeMinnesota


Outwash

Till - late or pre Wisconsin?

Dakota Formation

Tunnel City Group

Wonewoc Sandstone


Mt. Simon Sandstone

Igneous or metamorphicbedrock?

Grout

Waterlevel

4-inchcasing

Wellscreen

Grout

Waterlevel

4-inchcasing

Openhole


Site Name

County


MN Unique



1100

1000

900

800

700

600

0

100

200

300

400

500

Long Lake WA

Watowan

770439770427

Topsoil

Till - Des Moines Lobe (lowshale member)

Till - Des Moines Lobe(moderate shale member)

Outwash - Unnamedcarbonate-rich formation(northwest source)

Dakota Formation(Cretaceous, Cenomanian)shale and sandstone

Unnamed unit (Cretaceous?,Albian/Cenomanian) shaleand sandstone


Saprolith (pre-Mount Simon;Middle Cambrian?)

Granite/gneiss(Neoarchean/Mesoarchean)

Grout

Waterlevel

4-inchcasing

Wellscreen

Grout

Waterlevel

4 inchcasing

Openhole


Site Name

County


MN Unique



1000

900

800

700

0

100

200

300

Lake Hanska WA

Brown

760692760651

Top soil

outwash




Dakota Formation Sandstoneand Shale

Undifferentiated CretaceousShale and sandstone

Mount Simon sandstone?

Igneous or metamorphicbedrock

Waterlevel

Grout

4 inchcasing

Wellscreen

Surfaceseal

Grout


Site Name

County


MN Unique



1000

900

800

0

100

200

Helget Braulick WMA

Brown

768260768259

Topsoil


Outwash (NW source)

Till (NW source)

Till and outwash undiff.

Dakota Formation sandstoneand shale

Undifferentiated Cretaceoussandstone and shale

Mt. Simon sandstone

Fort Ridgely Granite

Grout

Waterlevel

4-inchcasing

WellScreen

Grout

Waterlevel

4 inchcasing

Wellscreen


Site Name

County


MN Unique



1100

1000

900

800

700

600

500

0

100

200

300

400

500

600

Exceder WMA

Martin

768139768125

Top soil


Till (NW source)

Outwash (NW source)

Till (NW source)

Till or lake deposit - Undiff.

Dakota Formation (UpperCretaceous)

Tunnel City Group, LoneRock Formation

Wonewoc Sandstone



Grout

Waterlevel

4-inchcasing

WellScreen

Grout

Waterlevel

4 inchcasing

Openhole


Site Name

County


MN Unique



900

800

700

600

0

100

200

300

400

Swan Lake WMA - Courtland West Unit

Nicollet

768262768261

Topsoil


Till (nw source)

Lacustrine Deposits - preWisc.

Outwash - pre Wisc.

Till - pre Wisc.

Outwash - pre Wisc.

Dakota Formation -Cretaceous

Cretaceous Deposits

Wonewoc Sandstone

Sioux Quartzite

Grout

4-inchcasing

Waterlevel

Wellscreen

Grout

Waterlevel

8 inchcasing

4 inchcasing

Openhole


Site Name

County


MN Unique



1000

900

800

700

600

500

400

0

100

200

300

400

500

600

Case WMA

Watonwan

760686760687

Top soil

Lake Deposits


Till - undiff.

Till (NW source)

ice contact - Unnamed

Till (NE source)


Tunnel City Group

Birkmose Member

Wonewoc Sandstone


Mt. Simon sandstone

Rhyolite

Grout

Waterlevel

4-inchcasing

Wellscreen

Grout

Waterlevel

Openhole


Site Name

County


MN Unique



900

800

700

600

0

100

200

300

400

Bergdahl WMA

Watonwan

760690760691

Lake Deposits - Glacial LakeMinnesota



Outwash - Des Moines orRainy Lobe?

Till & outwash - ice contactdeposits Des Moines orRainy Lobe?

Till - Browerville Formation

Till - Unamed low tomoderate carbonate (Rainysource)


Mt. Simon sandstone

Granite/Gniess

Grout

Waterlevel

4-inchcasing

Wellscreen

Grout

Waterlevel

4-inchcasing

Openhole


Site Name

County


MN Unique



900

800

700

600

500

400

0

100

200

300

400

500

600

Sibley County Landfill

Sibley

770441770440

Top Soil

Till - New Ulm Formation


Till - Traverse des Sioux Fm

Till - Browerville Formation

Till - Unnamed carbonate-rich formation (northwestsource)


Outwash - Unnamed low tomoderate carbonateformation (northeast Rainysource)

Lake deposit -Undifferentiated


Lake deposit -Undifferentiated


Fond du Lac (?)Mesoproterozoic

Grout

Waterlevel

4-inchcasing

WellScreen

Grout

Waterlevel

4 inchcasing

Openhole

Firstboring(270298sealed)

south-central minnesota groundwater monitoring of the mt. simon...

Documents