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Home , Amherstburg Formation, Antrim Shale, Bayport Limestone, Black River Formation, Bois Blanc Formation, Coldwater Shale

In cooperation with the State of , Department of Environmental Quality

Summary of Hydrogeologic Conditions by County for the State of Michigan

Open-File Report 2007-1236

U.S. Department of the Interior U.S. Geological Survey Summary of Hydrogeologic Conditions by County for the State of Michigan

By Beth A. Apple and Howard W. Reeves

In cooperation with the State of Michigan, Department of Environmental Quality

Open-File Report 2007-1236

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark D. Myers, Director

U.S. Geological Survey, Reston, : 2007

For more information about the USGS and its products: Telephone: 1-888-ASK-USGS World Wide Web: http://www.usgs.gov/ Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report.

Suggested citation Beth, A. Apple and Howard W. Reeves, 2007, Summary of Hydrogeologic Conditions by County for the State of Michi- gan. U.S. Geological Survey Open-File Report 2007-1236, 78 p.

Cover photographs Clockwise from upper left: Photograph of Pretty Lake by Gary Huffman. Photograph of a river in winter by Dan Wydra. Photographs of and the Looking Glass River by Sharon Baltusis. iii Contents

Abstract...... 1 Introduction...... 1 Purpose and Scope...... 1 Study Area...... 1 County Summaries...... 3 Alcona County...... 3 Alger County...... 3 Allegan County...... 4 Alpena County...... 5 Antrim County...... 6 Arenac County...... 6 Baraga County...... 8 Barry County...... 8 Bay County...... 9 Benzie County...... 10 Berrien County...... 11 Branch County...... 11 Calhoun County...... 12 Cass County...... 13 Charlevoix County...... 13 Cheboygan County...... 14 Chippewa County...... 15 Clare County...... 16 Clinton County...... 17 Crawford County...... 18 Delta County...... 18 Dickinson County...... 19 Eaton County...... 20 Emmet County...... 22 Genesee County...... 23 Gladwin County...... 24 Gogebic County...... 25 Grand Traverse County...... 26 Gratiot County...... 27 Hillsdale County...... 28 Houghton County...... 29 Huron County...... 29 Ingham County...... 31 Ionia County...... 32 Iosco County...... 33 Iron County...... 34 Isabella County...... 35 Jackson County...... 35 Kalamazoo County...... 36 Kalkaska County...... 37 iv

Kent County...... 37 Keweenaw County...... 39 Lake County...... 39 Lapeer County...... 40 Leelanau County...... 41 Lenawee County...... 42 Livingston County...... 43 Luce County...... 44 Mackinac County...... 45 Macomb County...... 46 Manistee County...... 47 Marquette County...... 47 Mason County...... 48 Mecosta County...... 49 Menominee County...... 49 Midland County...... 50 Missaukee County...... 51 Monroe County...... 51 Montcalm County...... 53 Montmorency County...... 53 Muskegon County...... 54 Newaygo County...... 55 Oakland County...... 56 Oceana County...... 57 Ogemaw County...... 57 Ontonagon County...... 58 Osceola County...... 59 Oscoda County...... 59 Otsego County...... 59 Ottawa County...... 60 Presque Isle County...... 61 Roscommon County...... 62 Saginaw County...... 62 Sanilac County...... 63 Schoolcraft County...... 64 Shiawassee County...... 65 St. Clair County...... 66 St. Joseph County...... 67 Tuscola County...... 68 Van Buren County...... 69 Washtenaw County...... 69 Wayne County...... 71 Wexford County...... 72 References Cited...... 73 Figures

1. Location of counties in Michigan...... 2  Conversion Factors, Abbreviations, and Vertical Datum

Multiply By To obtain Length inch (in.) 2.54 centimeter (cm) foot (ft) 0.3048 meter (m) mile (mi) 1.609 kilometer (km) Area acre 4,047 square meter (m2) square foot (ft2) 0.09290 square meter (m2) square inch (in2) 6.452 square centimeter (cm2) section (640 acres or 1 square mile) 2.59 square kilometer (km2) square mile (mi2) 2.590 square kilometer (km2) Volume gallon (gal) 3.785 liter (L) gallon (gal) 0.003785 cubic meter (m3) million gallons (Mgal) 3,785 cubic meter (m3) cubic foot (ft3) 0.02832 cubic meter (m3) cubic yard (yd3) 0.7646 cubic meter (m3) acre-foot (acre-ft) 1,233 cubic meter (m3) Flow rate acre-foot per day (acre-ft/d) 0.01427 cubic meter per second (m3/s) acre-foot per year (acre-ft/yr) 1,233 cubic meter per year (m3/yr) foot per second (ft/s) 0.3048 meter per second (m/s) cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s) cubic foot per second per square 0.01093 cubic meter per second per square mile [(ft3/s)/mi2] kilometer [(m3/s)/km2] cubic foot per day (ft3/d) 0.02832 cubic meter per day (m3/d) gallon per minute (gal/min) 0.06309 liter per second (L/s) gallon per day (gal/d) 0.003785 cubic meter per day (m3/d) gallon per day per square mile 0.001461 cubic meter per day per square [(gal/d)/mi2] kilometer [(m3/d)/km2] million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3/s) million gallons per day per square 1,461 cubic meter per day per square mile [(Mgal/d)/mi2] kilometer [(m3/d)/km2] mile per hour (mi/h) 1.609 kilometer per hour (km/h) Specific capacity gallon per minute per foot 0.2070 liter per second per meter [(L/s)/m] [(gal/min)/ft)] Hydraulic conductivity foot per day (ft/d) 0.3048 meter per day (m/d) Hydraulic gradient foot per mile (ft/mi) 0.1894 meter per kilometer (m/km) Transmissivity* foot squared per day (ft2/d) 0.09290 meter squared per day (m2/d) vi

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88). Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). Altitude, as used in this report, refers to distance above the vertical datum. *Transmissivity: The standard unit for transmissivity is cubic foot per day per square foot times foot of thickness [(ft3/d)/ft2]ft. In this report, the mathematically reduced form, foot squared per day (ft2/d), is used for convenience. Summary of Hydrogeologic Conditions by County for the State of Michigan

By Beth A. Apple and Howard W. Reeves

Abstract

Summaries of the major hydrogeologic features for various other fields. The database is provided on‑line and each county in Michigan are presented. Each summary is envisioned to provide a first‑stop for State regulators, includes a listing of the major watersheds in the county and water‑resources professionals, and the public to gather a description of the hydrogeology of the major in existing ground‑water resources data for Michigan. The the county. Aquifer properties reported in the literature are county summaries prepared for the database are provided given if available. Reports describing the hydrogeology of in this report. each county are cited. This work was prepared to provide For each county summary, the distribution of wells a brief introduction to the ground‑water setting for each between wells completed in bedrock aquifers and those county. glacial deposits is provided using records from the digital water well log database, Wellogic, maintained by the State of Michigan. This distribution is intended to indicate the major local aquifer system used for domestic supply Introduction to the reader. Each summary then describes the aquifer characteristics for post‑glacial alluvium, glacial deposits, and bedrock units. Citations are provided to document the Purpose and Scope summary. The level of detail for each county depends on the available information for the county, and no additional Public Act 148, Section 32802 (Michigan State interpretive work was done in the preparation of these Legislature, 2003) required the Department of Environmen‑ summaries. Many of the reports cited in this report are tal Quality (MDEQ) of the State of Michigan to create a available through the internet at the ground‑water inven‑ ground‑water inventory and map that includes eight specific tory and map website that is maintained by Michigan State requirements, a general requirement for a ground‑water University (http://gwmap.rsgis.msu.edu). inventory, and a directive to make the map and inventory accessible by the public. This document provides a sum‑ mary of hydrogeologic conditions for each county in the Study Area State that were prepared for the ground‑water inventory. The goal of the effort documented by this report was The study area for this report is the entire State of to provide a database of hydrogeologic information for Michigan. This report is a compilation of county hydro‑ the State. This database indexes reports that describe the geologic summaries created for the ground‑water inven‑ hydrogeology and ground‑water resources of the State of tory. Each county summary is designed to provide a brief Michigan, provides aquifer‑test results from these reports, overview of the ground‑water resources in the county. and provides an overview summary of the hydrogeologic conditions for each county. The database may be searched by county, hydrologic unit code, aquifer type, author, and  Summary of Hydrogeologic Conditions by County for the State of Michigan

89o 439 48o

88o

KEWEENAW o UPE 89 LAKE S RIOR HOUGHTON 47o 90o 85o ONTONAGON 86o BARAGA MARQUETTE o 87 LUCE GOGEBIC

IRON ALGER SCHOOLCRAFT DICKINSON CHIPPEWA MACKINAC 84o DELTA 46o

MENOMINEE EMMET CHEBOYGAN L A PRESQUE ISLE K CHARLEVOIX E ALPENA MONTMORENCY H ANTRIM OTSEGO U 45o R LEELANAU O N KALKASKA ALCONA CRAWFORD OSCODA N A GRAND BENZIE G TRAVERSE I

H MANISTEE WEXFORD MISSAUKEE OGEMAW IOSCO C I ROSCOMMON

M

o E 83 MASON LAKE OSCEOLA CLARE GLADWIN ARENAC K 44o A W A

L HURON GINY SA A OCEANA NEWAYGO MECOSTA ISABELLA MIDLAND BAY B

TUSCOLA SANILAC

MONTCALM GRATIOT SAGINAW

MUSKEGON KENT LAPEER GENESEE ST CLAIR IONIA CLINTON SHIAWASSEE OTTAWA 43o

MACOMB OAKLAND ALLEGAN BARRY EATON INGHAM LIVINGSTON

VAN BUREN KALAMAZOO CALHOUN JACKSON WASHTENAW WAYNE

CASS ST JOSEPH BRANCH HILLSDALE LENAWEE MONROE 42o BERRIEN

LAKE ERIE Base from U.S. Geological Survey 1:500,000 map 0 10 20 30 40 50 MILES

0 20 40 60 KILOMETERS

Figure 1. Location of counties in Michigan. County Summaries 

County Summaries The Sunbury is a black, carbonaceous shale that underlies the (Harrell and others, 1991). The thins towards the center of the and is 147.6 ft thick in the eastern portion of the State (Guts‑ Alcona County chick and Sandberg, 1991). Shale is generally considered to be a confining unit. Alcona County is in the northeastern portion of the The Berea underlies the Sunbury Shale. The Lower Peninsula of Michigan. The Lone Lake‑Ocqueoc, is fine‑ to medium‑grained sandstone, and Thunder Bay, Au Sable, and watersheds drain the is greater than 114.8 ft thick in eastern Michigan and thins to county. According to the February 2005 Wellogic database, the west (Gutschick and Sandberg, 1991). The Berea Sand‑ approximately 94 percent of the wells in Alcona County are stone grades into the underlying and thus the completed in the glacial deposits, and less than 1 percent in upper portion of the shale is silty or sandy. The Bedford Shale the bedrock units. There is insufficient information to make is primarily gray shale in the Michigan Basin. The Bedford this distinction for 6 percent of the wells in the county. Shale may be greater than 213.3 ft thick in eastern Michigan With the available information, glacial cannot and thins toward the center of the Michigan Basin (Gutschick be regionally correlated in the subsurface in the Michigan and Sandberg, 1991). Shale is generally considered to be a Basin. This is likely due to the lateral and vertical hetero‑ confining unit. geneity of glacial deposits that resulted from a complex The is composed of primarily carbona‑ depositional history (Westjohn and others, 1994). The glacial ceous, black to dark‑gray shale. Near the base of the sequence, deposits in Alcona County range from 101 to 800 ft thick. thin layers of gray shale and may occur. The major However, the majority of the deposits range from 201 to 600 ft constituents in the Antrim Shale consist of quartz, illite, and thick (Western Michigan University, 1981). The glacial depos‑ kerogen. Kaolinite, chlorite, and pyrite also compose the Ant‑ its consist of , outwash, and lacustrine deposits. Fine‑ to rim Shale. The Antrim Shale has been found to have bitumi‑ coarse‑grained till occurs in moraines and till plains. Glacial nous limestone concretions up to 3 ft in diameter (Matthews, outwash and ice‑contact outwash is also present in the county, 1993). The Antrim Shale can be up to 656 ft thick, which and primarily consists of sand and gravel. Coarse‑grained occurs at the center of the Michigan Basin (Gutschick and lacustrine deposits are present on the surface in the south‑cen‑ Sandberg, 1991). Antrim Shale is generally not considered to tral, southeastern, and northeastern portions of the county be an aquifer, however, locally it may yield small quantities of (Farrand and Bell, 1982). Aquifers in the glacial deposits water. consist largely of sands and gravels and vary regionally in thickness and permeability. Bedrock underlies the glacial deposits. The bedrock Alger County surface of Alcona County is composed of the Marshall Sand‑ stone, Coldwater Shale, Sunbury Shale, Berea Sandstone, Alger County is in the central portion of the Upper Bedford Shale, and Antrim Shale (Milstein, 1987). The Mar‑ Peninsula of Michigan. The Betsy‑Chocolay, Tahquamenon, shall Sandstone forms the bedrock surface in the southwestern , Tacoosh‑Whitefish, Fishdam‑Sturgeon, and portion of the county. The consists of one Manistique watersheds drain the county. According to the or more stratigraphically continuous permeable . February 2005 Wellogic database, approximately 28 percent of The upper sandstone is a quartzarenite to sublitharenite that the wells in Alger County are completed in the glacial depos‑ is referred to as the Napoleon Sandstone Member. A shale, its, and 68 percent in the bedrock units. There is insufficient siltstone, and/or carbonate layer separates the Napoleon Sand‑ information to make this distinction for 4 percent of the wells stone Member from the underlying lower Marshall sandstone. in the county. The glacial aquifer is generally unconfined, and The lower Marshall sandstone is comprised of two units. The overlies the bedrock aquifers, except where glacial deposits upper unit is generally 50 to 125 ft of fine‑ to medium‑grained are absent. quartzarenite to sublitharenite. The basal unit is a fine‑ to Aquifers in the glacial deposits consist largely of sands medium‑grained litharenite that ranges in thickness from 30 and gravels and vary regionally in thickness and permeability. to 125 ft. Permeable sandstones in the Marshall Sandstone With the available information, glacial lithologies cannot be comprise the Marshall aquifer. The Marshall aquifer ranges regionally correlated in the subsurface. This is likely due to in thickness from 75 to greater than 200 ft within the State the lateral and vertical heterogeneity of glacial deposits that (Westjohn and Weaver, 1998). The Marshall aquifer contains resulted from a complex depositional history (Westjohn and fresh water in Alcona County (Westjohn and Weaver, 1996c). others, 1994). The glacial deposits range from 0 to greater than The Coldwater Shale underlies the Marshall Sandstone, 200 ft thick in Alger County, and include lacustrine deposits, and consists of primarily shale with interbeds or lenses of till, and outwash. Sand is the major constituent in lacustrine sandstone, siltstone, and dolomite. The Coldwater Shale is deposits, which locally overlie other types of glacial deposits. relatively impermeable and is considered a confining unit in The lacustrine deposits yield moderate supplies of water. Till most of Michigan (Westjohn and Weaver, 1998). is present in moraines and till plains. The Munising and New‑  Summary of Hydrogeologic Conditions by County for the State of Michigan berry Moraines are present in Alger County. The Munising supply many wells with water, because shallower ground‑wa‑ Moraine trends from the northeast to the southwest. The New‑ ter resources are available. The may be berry Moraine is present in T45N R19W and T44N R19W. semi‑confined or confined in areas because the upper portion The moraines are composed primarily of sandy till with lenses of the formation is silty to shaley (Vanlier, 1963b). Specific of sand and gravel outwash interbedded. The morainal depos‑ capacities are near 1 gpm/ft for the Munising Formation in its may yield small to moderate supplies of water. Till‑plain Pictured Rocks National Lakeshore (Handy and Twenter, deposits, which consist of sandy‑clay or boulder till, generally 1985). According to the Public Water Supply database, the do not supply water. The outwash deposits consist of primar‑ estimated transmissivity for wells completed in the Munising ily sand and some gravel (Vanlier, 1963b). Where the outwash Formation is approximately 535 ft2/day. deposits are the most extensive, Vanlier (1963b) estimates the The , which lies underneath the average thickness to be 100 ft. Outwash deposits may yield Munising Formation, is moderately permeable from joints moderate to large water supplies, which locally has high iron and fractures in the upper third of the formation, especially content. where it forms the bedrock surface. The greatest thickness Specific capacities range from 1 to 14 gal/min/ft for the of Jacobsville Sandstone is 1,000 ft along the shore of Lake glacial aquifer in Pictured Rocks National Lakeshore (Handy Superior and thins to the south. Jacobsville Sandstone is pre‑ and Twenter, 1985). Based upon eight wells located near the dominately medium‑grained sandstone interbedded with shale, Wetmore tribal community, glacial aquifer transmissivity siltstone, and coarser sandstone (Vanlier, 1963b). Specific ranges from 95 to 310 ft2/day (Brannen, 1997). According to capacities range between 0.1 to 1 gal/min/ft for the Jacobsville the Public Water Supply database, the estimated transmissiv‑ Sandstone in Pictured Rocks National Lakeshore (Handy and ity for glacial wells in the county ranges from approximately Twenter, 1985). The Jacobsville Sandstone supplies hard water 2,150 to 5,615 ft2/day. with high concentrations of iron. In some wells, the water Glacial deposits, when present, overlie the bedrock units. from Jacobsville Sandstone is saline (Vanlier, 1963b). Igneous The units that form the bedrock surface generally subcrop and metamorphic rocks underlie the Jacobsville trending southwest to northeast. The youngest units form the Sandstone and are not a source of water (Handy and Twenter, bedrock surface in the southeastern portion of the county and 1985). get progressively older to the northwest. Due to the angle of the bedrock, which dips south, the layers diminish to the north. The and underlying Black River Allegan County Formation, which are composed of limestone and dolomite Allegan County is in the southwestern Lower Peninsula with interbedded shale, are the uppermost bedrock units in the of Michigan. The western edge of the county is along the Lake county. This combined layer is thinner in the northern portion Michigan shoreline. The Lake Michigan, Black-Macatawa, of the county and is the major source of water in the south‑ Kalamazoo, Lower Grand, and Thornapple watersheds drain western portion of the county. The Trenton and Black River the county. According to the February 2005 Wellogic data‑ Formations supply small yields of hard water with high iron base, approximately 89 percent of the wells in Allegan County concentrations. Bacterial contamination is also a problem in are completed in the glacial deposits, and 8 percent in the water from this layer. In some areas, impermeable layers in the bedrock units. There is insufficient information to make this Trenton and Black River Formations act as confining layers distinction for 3 percent of the wells in the county. (Vanlier, 1963b). With the available information in the State, glacial Vanlier (1963b) defines the bedrock underlying the Tren‑ lithologies cannot be regionally correlated in the subsurface. ton and Black River Formations as and This is likely due to the lateral and vertical heterogeneity of dolomite and sandstone undifferentiated. Handy and Twenter glacial deposits that resulted from a complex depositional (1985) define this same layer as the Prairie du Chien Group history (Westjohn and others, 1994). The surficial deposits in and underlying Trempealeau Formation. Dolomite in this layer Allegan County consist of dunes, lacustrine deposits, outwash can supply small amounts of water, usually in the western and small amounts of post‑glacial alluvium, and till. Dune part of Alger County, where the sandstone from this layer is sand primarily exists in the western portion of the county thin or not present. In other areas of the county, the sandstone along Lake Michigan. Lacustrine deposits are primarily sand member supplies water. Based on nine wells completed in the and gravel and are concentrated in the center of the county. Prairie du Chien Group, near the Wetmore tribal community, Outwash and post‑glacial alluvium deposits occur mostly in bedrock aquifer transmissivity ranges from 6.7 to 26.7 ft2/day the eastern portion of the county and are composed of sand (Brannen, 1997). The Munising Formation and Jacobsville and gravel. Till is present in till plains and moraines. The till Sandstone underlie this layer. in Allegan County ranges from fine to coarse grained (Farrand The Munising Formation is composed of a fine‑ to medi‑ and Bell, 1982). um‑grained quartz sandstone, with lenses of coarser sandstone, Aquifers in the glacial deposits consist largely of sands and a basal layer. The Munising Formation and gravels, and vary regionally in thickness and permeability. supplies good quality water and is the most extensive aquifer According to the Public Water Supply database, the outwash in Alger County. However, the Munising Formation does not County Summaries  deposits have estimated transmissivities from aquifer tests that In the Michigan Basin, glacial aquifers consist of sand range from 9,547 to 79,900 ft2/day, while combined outwash and gravel that are part of a thick sequence of gla‑ and till have an estimated transmissivity of 6, 496 ft2/day. cial deposits. With the available information, glacial litholo‑ Bedrock underlies the glacial deposits. The bedrock sur‑ gies cannot be regionally correlated in the subsurface. This is face in Allegan County is composed of the Michigan Forma‑ likely due to the lateral and vertical heterogeneity of glacial tion, Marshall Sandstone, and Coldwater Shale. The Michigan deposits that resulted from a complex depositional history Formation subcrops in a small area in the northeastern portion (Westjohn and others, 1994). Glacial deposits are up to 600 ft of the county. Discontinuous siltstone and sandstone lenses, thick in Alpena County (Western Michigan University, 1981). along with shale, carbonate, and evaporite comprise the The glacial deposits in the county consist of till, outwash, and Michigan Formation. The Michigan Formation is considered a lacustrine deposits. The western and central portion of the confining unit (Westjohn and Weaver, 1996b). county is primarily composed of coarse‑grained till. Eskers The Marshall Sandstone underlies the Michigan Forma‑ are present in central portion of the county. Fine‑grained till tion and subcrops in the northeastern portion of the county. can also be found on the surface, but does not make up a large The greatest thickness of the Marshall Sandstone is 171 ft in percentage of the glacial deposits in the county. Outwash Allegan County (Riggs, 1938). The Marshall Sandstone is and ice‑contact outwash are found throughout the southwest‑ composed of an upper quartzarenite to sublitharenite that is ern and southeastern portions of the county, respectively. referred to as the Napoleon Sandstone Member (Riggs, 1938). Coarse‑grained lacustrine deposits are present on the surface A shale, siltstone, and/or carbonate layer separates the Napo‑ in the northeastern portion of the county and along the eastern leon Sandstone Member from the lower Marshall sandstone. border. In addition, sand dunes composed of fine‑ to medi‑ The lower Marshall Sandstone is comprised of two units. The um‑grained sand are present along the Lake Huron shoreline upper unit is generally 50 to 125 ft of fine‑ to medium‑grained and are also found inland. An area of peat and muck deposits quartzarenite to sublitharenite. The basal unit is a fine‑ to can be found in the northwestern portion of the county (Far‑ medium‑grained litharenite that ranges in thickness from 30 rand and Bell, 1982). to 125 ft (Westjohn and Weaver, 1998). Both the Napoleon The glacial deposits overlie the bedrock. The bedrock Sandstone Member and lower Marshall Sandstone are pres‑ surface of Alpena County is composed of the Sunbury Shale, ent in well logs from Allegan County (Riggs, 1938). Perme‑ Berea Sandstone, Bedford Shale, Antrim Shale, and Traverse able sandstones in the Marshall Sandstone are considered the Group. Sunbury Shale, Berea Sandstone, and Bedford Shale Marshall aquifer. The Marshall aquifer ranges in thickness subcrop in the southwestern portion of the county. The Antrim between 75 and greater than 200 ft thick within the State Shale and form the remainder of the bedrock (Westjohn and Weaver, 1998). The Marshall aquifer yields surface in the northern and southern portions of the county, fresh water in Allegan County (Westjohn and Weaver, 1996c). respectively (Milstein, 1987). The Coldwater Shale underlies the Marshall Sandstone. The Sunbury Shale is a black shale, which thins towards The Coldwater Shale subcrops in the central and western por‑ the center of the basin and is 147 ft thick in the eastern portion tion of Allegan County. In the County, the Coldwater Shale of the State (Gutschick and Sandberg, 1991). The Berea Sand‑ ranges from 700 to 860 ft thick when beneath the Marshall stone underlies the Sunbury Shale. The Berea Sandstone is Sandstone. Coldwater Shale consists of shale, sandstone, fine‑ to medium‑grained sandstone. It is greater than 114.8 ft siltstone, and carbonates. In Allegan County, cherty shale that thick in eastern Michigan and thins to the west (Gutschick and contains dolomite crystals, chert bands and dolomitic lime‑ Sandberg, 1991). The Berea Sandstone grades into the under‑ stone are common in the Coldwater Shale. Limestone layers lying Bedford Shale and thus the upper portion of the shale is may provide water to wells in areas of the county. However, silty or sandy. The Bedford Shale is primarily gray shale in the the water may be saline (Riggs, 1938). Michigan Basin. The Bedford Shale may be greater than 213 ft thick in eastern Michigan and thins toward the center of the Michigan Basin (Gutschick and Sandberg, 1991). Alpena County The Antrim Shale is composed of primarily carbona‑ ceous, black to dark‑gray shale. Near the base of the sequence, Alpena County is in the northeastern Lower Peninsula of thin layers of gray shale and limestone may occur. The major Michigan. The Lone Lake-Ocqueoc, Thunder Bay, Au Sable, constituents in the Antrim Shale consist of quartz, illite, and and Lake Huron watersheds drain portions of Alpena County. kerogen. Kaolinite, chlorite, and pyrite also compose the Ant‑ According to the February 2005 Wellogic database, approxi‑ rim Shale. The Antrim Shale has been found to have bitumi‑ mately 39 percent of the wells in Alpena County are com‑ nous limestone concretions up to 3 ft in diameter (Matthews, pleted in the glacial deposits, and 41 percent in the bedrock 1993). The Antrim Shale can be up to 656 ft thick, which units. There is insufficient information to make this distinction occurs at the center of the Michigan Basin (Gutschick and for 20 percent of the wells in the county. Glacial wells are Sandberg, 1991). more abundant in the southern portion of the county, while The Traverse Group primarily consists of fossiliferous bedrock wells dominate the northern portion of the county. limestone. In the western portion of the basin, porous dolo‑ mite and anhydrite may be present. In the eastern portion of  Summary of Hydrogeologic Conditions by County for the State of Michigan the basin, interlayers of shale are common. (Gardner, 1974). lenses, of sandstone, siltstone, and dolomite. The Coldwater The basal formation of the Traverse Group is the . Shale is relatively impermeable and is considered a confining Bell Shale has a maximum thickness of 80 ft (Catacosinos and unit in most of Michigan (Westjohn and Weaver, 1998). others, 2001). The majority of the bedrock wells in the county The Sunbury Shale is black shale that thins towards the occur where the Traverse group forms the bedrock surface. center of the basin and is 147.6 ft thick in the eastern por‑ There are several karst features that occur throughout the tion of the State (Gutschick and Sandberg, 1991). This unit northern portion of the county. The karst features are a result is generally not considered an aquifer. The Berea Sandstone of dissolution of the carbonate and evaporite bedrock units and underlies the Sunbury Shale. The Berea Sandstone is fine‑ to subsequent collapse of these units. Karst sinkhole lakes occur medium‑grained sandstone. It is greater than 114.8 ft thick in near Leer in Alpena County. Devil’s, Long, Fitzgerald, and eastern Michigan and thins to the west. The Berea Sandstone Mindack Lakes are considered karst solution lakes (Kimmel, grades into the underlying Bedford Shale and thus the upper 1983). portion of the shale is silty or sandy (Gutschick and Sandberg, 1991). Like the Sunbury Shale, the Bedford, Ellsworth, and Antrim County Antrim are generally not considered aquifers. The Bedford Shale is primarily gray shale in the Michigan Basin. Antrim County is in the northwestern Lower Peninsula. The Bedford Shale may be greater than 213.3 ft thick in The Manistee, Boardman-Charlevoix, and Lake Michigan eastern Michigan and thins toward the center of the Michigan watersheds can be found in the county. According to the Feb‑ Basin (Gutschick and Sandberg, 1991). The ruary 2005 Wellogic database, approximately 94 percent of the is composed of a gray to greenish‑gray shale. Ellsworth Shale wells in Antrim County are completed in the glacial deposits, generally contains some dolomite and may also be composed and less than 1 percent in the bedrock units. There is insuf‑ of sandstone and siltstone layers (Matthews, 1993). The ficient information to make this distinction for 6 percent of Antrim Shale is composed of primarily carbonaceous, black to the wells in the county. The majority of the bedrock wells are dark‑gray shale. Near the base of the sequence, thin layers of along the western shoreline. gray shale and limestone may occur. The major constituents of In the Michigan Basin, glacial aquifers consist of sand the Antrim Shale consist of quartz, illite, and kerogen. Kaolin‑ and gravel that are part of a thick sequence of Pleistocene ite, chlorite, and pyrite also compose the Antrim Shale. The glacial deposits. With the available information, glacial Antrim Shale has been found to have bituminous limestone lithologies cannot be regionally correlated in the subsurface. concretions up to 3 ft in diameter (Matthews, 1993). The Ant‑ This is likely due to the lateral and vertical heterogeneity of rim Shale can be up to 656 ft thick, which occurs at the center glacial deposits that resulted from a complex depositional of the Michigan Basin (Gutschick and Sandberg, 1991). history (Westjohn and others, 1994). In Antrim County, the The Traverse Group primarily consists of fossiliferous glacial deposits range from 11 to 1,000 ft thick; however, the limestone. In the western portion of the basin, porous dolo‑ majority of the deposits range from 200 to 800 ft in thickness mite and anhydrite may be present. In the eastern portion of (Western Michigan University, 1981). The glacial deposits are the basin, interlayers of shale are common. (Gardner, 1974). composed of outwash, till, and lacustrine deposits. Outwash Nearby in Charlevoix County, the transmissivity of the lime‑ consists of sand and gravel and is most abundant in the eastern stone ranges from 13.4 to 5,347.2 ft2/day (Cathcart, 1982). portion of the county. An isolated area of ice‑contact outwash The basal formation of the Traverse Group is the Bell Shale. is in the southeastern corner of the county. The till found Bell Shale has a maximum thickness of 80 ft (Catacosinos and in Antrim County is primarily coarse grained and occurs in others, 2001). moraines and till plains. A small amount of medium‑grained till occurs in the southwestern portion of the county. Moraines trend southwest to northeast across the county. Drumlins are Arenac County abundant on the till plains in the northwestern portion of the county. The lacustrine deposits are composed primarily of Arenac County is in the eastern north‑central portion of sand and gravel and are concentrated in the western portion of the Lower Peninsula of Michigan. The eastern portion of the the county (Farrand and Bell, 1982). According to the Public county borders . The county is considered part of Water Supply database, the estimated transmissivity for glacial the Saginaw Lowlands (Westjohn and Weaver, 1998). The Au wells ranges from approximately 1,200 to 14,170 ft2/day. Gres-Rifle, Kawkawlin-Pine, Tittabawassee, and Lake Huron According to the Public Water Supply database, the watersheds drain the county. According to the February 2005 estimated transmissivity for a bedrock well in the county is Wellogic database, approximately 41 percent of the wells in approximately 2,320 ft2/day. The bedrock surface in Antrim Arenac County are completed in the glacial deposits, and 56 County consists of the Coldwater Shale, Sunbury Shale, Berea percent in the bedrock units. There is insufficient informa‑ Sandstone, Bedford Shale, Antrim Shale, Ellsworth Shale, tion to make this distinction for 3 percent of the wells in the and Traverse Group (Milstein, 1987). Within the State, the county. Coldwater Shale consists of primarily shale with interbeds, or County Summaries 

In the Michigan Basin, glacial aquifers consist of sand ‑aged . The and gravel that are part of a thick sequence of Pleistocene gla‑ is composed of medium‑ to coarse‑grained sandstone (Cohee cial deposits. With the available information, glacial litholo‑ and others, 1951). In some areas in Arenac County, the Parma gies cannot be regionally correlated in the subsurface. This is Sandstone is completely eroded; however, where the Parma likely due to the lateral and vertical heterogeneity of glacial Sandstone is present, it ranges in thickness from 30 to 50 ft deposits that resulted from a complex depositional history (Pringle, 1937). The Bayport Limestone is a fossiliferous, (Westjohn and others, 1994). The thickness of glacial deposits cherty limestone, often with interbedded sandstone and var‑ in Arenac County ranges from 0 ft in the west to 400 ft in the ies considerably in thickness from one area to another. The northwest (Western Michigan University, 1981). The glacial Bayport Limestone and Parma Sandstone appear to interfin‑ deposits in Arenac County are composed of primarily basal ger throughout the Michigan Basin (Westjohn and Weaver, lodgement till and lacustrine deposits (Westjohn and Weaver, 1996a). These units are hydraulically connected, and together 1994). Sand and gravel lacustrine deposits are primarily in they form the Parma-Bayport aquifer (Westjohn and Weaver, the central and northern parts of the county, while clay and 1996a). The Parma-Bayport aquifer is approximately 100 silt-lacustrine deposits are common in the southern and eastern to 150 ft thick within the Michigan Basin. Please note that parts of the county (Farrand and Bell, 1982). Moraines are due to the uncertainty of stratigraphic relationship between also present in Arenac County. The Port Huron Moraine trends these units, in other reports this aquifer may be delineated northeastward, from the southwestern corner of the county into differently. The Parma-Bayport aquifer yields saline water in Clayton and Mason Townships. Moraines are also present in Arenac County (Westjohn and Weaver, 1996c). the northeastern portion of Whitney Township, the northwest Underlying the Bayport Limestone is the Michigan portion of Moffat Township, and the northwestern most corner Formation. The Michigan Formation consists of layers of of the county. The till comprising the moraines is generally clay‑rich, fine‑grained sandstone, siltstone, anhydrite or gyp‑ composed of boulder‑rich clay, with areas of sand (Pringle, sum, dolomite, limestone, and shale (Pringle, 1937; Westjohn 1937). According to the Public Water Supply database, glacial and Weaver, 1996b). The Michigan Formation ranges from wells in Arenac County have estimated transmissivities from 30 to 260 ft thick in the county. However, generally in Arenac aquifer tests that range from 495 to 3,450 ft2/day. County, the Michigan Formation is less than 100 ft thick (Prin‑ Bedrock underlies the glacial deposits, except where bed‑ gle, 1937). The lower permeability lithologies of the Michigan are present (Pringle, 1937). The bedrock surface Formation are considered a confining unit that separates the of Arenac County is composed of the , Parma-Bayport aquifer from the underlying Marshall aquifer Bayport Limestone, Michigan Formation, Marshall Sandstone, (Westjohn and Weaver, 1996b). and Coldwater Shale (Milstein, 1987). Bedrock generally The Marshall Sandstone underlies the Michigan Forma‑ dips to the southwest (Pringle, 1937). According to the Public tion. The Marshall Sandstone consists of one or more strati‑ Water Supply database the estimated transmissivity from aqui‑ graphically continuous permeable sandstones. The upper fer tests for a bedrock well in Arenac County was 136 ft2/day. sandstone is a quartzarenite to sublitharenite that is referred to In Arenac County, the thickness of the Saginaw Forma‑ as the Napoleon Sandstone Member (Westjohn and Weaver, tion ranges from 90 ft, near Rifle River, and increases to the 1998). In Arenac County, the Napoleon Sandstone Member southwest to Adams Township, where it is greater than 250 ft varies from 100 to 270 ft thick (Pringle, 1937). A shale, silt‑ (Pringle, 1937). Interbedded sandstone, siltstone, shale, coal, stone, and/or carbonate layer separates the Napoleon Sand‑ and limestone compose the Saginaw Formation The Saginaw stone Member from the lower Marshall sandstone. The lower aquifer consists of hydraulically‑connected sandstones in the Marshall sandstone is comprised of two units, which com‑ Saginaw Formation (Westjohn and Weaver, 1998). Within the bined range from 70 to 250 ft in thickness in Arenac County State, the Saginaw aquifer ranges from less than 100 to 370 ft (Pringle, 1937; Westjohn and Weaver, 1998). The upper unit is thick. The Saginaw aquifer yields fresh and saline water in the generally 50 to 125 ft of fine‑ to medium‑grained quartzarenite southwest and southeast portions of Arenac County, respec‑ to sublitharenite. The basal unit is a fine‑ to medium‑grained tively (Westjohn and Weaver, 1996c). The Saginaw confining litharenite that ranges in thickness from 30 to 125 ft. Per‑ unit underlies the Saginaw aquifer. The Saginaw confining meable sandstones in the Marshall Sandstone comprise the unit ranges from less than 100 to 240 ft thick within the State, Marshall aquifer. The Marshall aquifer ranges in thickness and is mostly shale, with thin layers of discontinuous sand‑ from 75 to greater than 200 ft within the State (Westjohn and stone, siltstone, limestone, and coal. The permeable layers Weaver, 1998). The Marshall aquifer is capable of supplying within the Saginaw confining unit appear to be isolated from large quantities of water. The Marshall aquifer yields mostly the regional ground‑water‑flow system (Westjohn and Weaver, saline water in Arenac County, except for an area in the north‑ 1996a). ern portion of the county, where the aquifer yields fresh water The Saginaw confining unit separates the Saginaw aqui‑ (Westjohn and Weaver, 1996c). fer from the underlying Parma-Bayport aquifer. The Parma The Coldwater Shale underlies the Marshall Sandstone, Sandstone is often considered the basal unit of the Saginaw and consists of primarily blue and gray shale with interbeds, Formation, although the stratigraphic relationship is not or lenses, of sandstone, siltstone, and dolomite (Pringle, 1937; clear between the Saginaw Formation, Parma Sandstone, and Westjohn and Weaver, 1996b). The Coldwater Shale is rela‑  Summary of Hydrogeologic Conditions by County for the State of Michigan tively impermeable and is considered a confining unit in most transmissivity of the bedrock aquifers was calculated using of Michigan (Westjohn and Weaver, 1996b). the specific capacity values of Doonan and Byerlay (1973) and ranges from 1 to 600 ft2/day. About half the bedrock wells in Baraga County acquire water from the Jacobsville Sand‑ Baraga County stone. Water from the Jacobsville Sandstone ranges from soft to very hard and iron concentration varies. Small amounts of Baraga County is in the western portion of the Upper water are obtained from fractures within the upper portion of Peninsula of Michigan. Sturgeon, Dead-Kelsey, Lake Supe‑ the Marquette Range Supergroup. Water from the Marquette rior, Brule, and Michigamme watersheds can be found in the Range Supergroup is usually moderately hard to very hard. county. According to the February 2005 Wellogic database, Laurentian granite and gneiss may also provide small yields of approximately 17 percent of the wells in Baraga County water from fractures. However, the water is hard and contains are completed in the glacial deposits, and 75 percent in the iron (Doonan and Byerlay, 1973). bedrock units. There is insufficient information to make this distinction for 8 percent of the wells in the county. Most wells in the county only produce small yields suitable for domestic Barry County use. Doonan and Byerlay (1973) identify a layer of swamp deposits and Holocene alluvium, the glacial aquifer, and three Barry County is in the southwestern Lower Peninsula of bedrock aquifers: the Jacobsville Sandstone, the Marquette Michigan. The Thornapple and Kalamazoo watersheds drain Range Supergroup, and Laurentian granite and gneiss. It is not the county. According to the February 2005 Wellogic database, clear which aquifers are confined or unconfined. approximately 88 percent of the wells in Barry County are Swamp deposits, consisting of muck and silt, and Holo‑ completed in the glacial deposits, and 9 percent in the bedrock cene alluvium are concentrated in the northwestern portion of units. There is insufficient information to make this distinction the county and also occur sporadically in patches. Small yields for 3 percent of the wells in the county. The Marshall aquifer of water are possible from the swamp deposits and Holocene is the primary bedrock aquifer in the county. alluvium, but may be high in iron concentrations (Doonan and With the available information, glacial lithologies cannot Byerlay, 1973). be regionally correlated in the subsurface. This is likely due Aquifers in the glacial deposits consist largely of sands to the lateral and vertical heterogeneity of glacial deposits that and gravels, and vary regionally in thickness and permeabil‑ resulted from a complex depositional history (Westjohn and ity. Glacial deposits are composed of till, outwash, stream others, 1994). The glacial deposits in Barry County range in deposits, and lacustrine deposits. Unstratified glacial depos‑ thickness from 150 to 400 ft (Lilienthal, 1974). Glacial depos‑ its include sandy to clayey till in moraines and till plains. its in the county include till, outwash, and lacustrine deposits. Stratified deposits that are composed of till include: kames, End moraines in the county are the result of the retreat of kame terraces, and eskers. Other stratified glacial deposits are the Lake Michigan and Saginaw Lobes of the Laurentide Ice sand and gravel outwash, stream deposits, and clay and sand Sheet. The moraines present from the Lake Michigan Lobe lacustrine deposits. Three major moraines have been identi‑ occur in the west and southwestern portions of the county, fied in Baraga County. The Keweenaw Moraine lies along and trend generally southwest to northeast. This moraine is the Keweenaw Bay. The Marenisco Moraine is located in the predominantly poorly‑sorted, coarse‑grained till, composed of southern portion of the county. The Covington Moraine trends sand and gravel, and has stony, boulder‑rich till interbedded. northeast from the Marenisco Moraine, near Covington. Small The moraines formed from the Saginaw Lobe trend gener‑ to moderate yields of water may be obtained from moraines. ally from the northeast to southwest and are located in the Outwash deposits are dispersed throughout the county and are northwestern, central, and eastern portion of the county. These often covered by postglacial deposits. However, the largest moraines are composed of poorly sorted, coarse deposits that area of outwash in the county is located near the Keweenaw fine toward the till plains. Till plains are located in the north‑ Moraine and is partially overlain by lacustrine deposits. In ern and eastern parts of Barry County, and consist of loamy, the west‑central portion of the county, is the largest lacustrine clayey‑till. Outwash is located throughout the county. Outwash deposit. This deposit is up to 200 ft thick. Lacustrine depos‑ is composed of primarily well‑sorted, sand and gravel. Lacus‑ its yield moderate supplies of water in Baraga County. The trine clay is dispersed throughout the outwash (Brewer, 1991). transmissivity of the glacial aquifer was calculated using the Glacial aquifers consist of sand and gravel that are part specific capacity values of Doonan and Byerlay (1973) and of a thick sequence of glacial deposits (Westjohn and others, ranges from 20 to 3,948 ft2/day. Ground‑water supplies from 1994). In Barry County, the glacial aquifer consists of primar‑ the glacial aquifer tend to be high in iron, and occasionally ily outwash and morainal deposits. According to the Public have a low pH. The water ranges from soft to very hard and Water Supply database, the estimated transmissivity for glacial may be high in iron content. (Doonan and Byerlay, 1973). wells on the outwash plains in the county range from approxi‑ Bedrock underlies glacial deposits, where glacial deposits mately 12,205 to 31,250 ft2/day. It is common for glacial wells are present. In areas where glacial deposits are absent or to have high levels of chloride and nitrate in Barry County thin, water must be obtained from the bedrock aquifers. The (Brewer, 1991). County Summaries 

Bedrock underlies the glacial deposits. The bedrock from 30 to 125 ft. Permeable sandstones in the Marshall Sand‑ dips to the northeast. The bedrock surface includes, generally stone comprise the Marshall aquifer. The Marshall aquifer from northeast to southwest, the Saginaw Formation, Bay‑ ranges in thickness from 75 to greater than 200 ft within the port Limestone, Michigan Formation, Marshall Sandstone, State (Westjohn and Weaver, 1998). The Marshall aquifer is and Coldwater Shale. The Saginaw Formation is composed the primary bedrock aquifer in Barry County (Brewer, 1991). of sandstone, siltstone, shale, limestone, and coal. Sandstone According to the Public Water Supply database, the estimated with layers of shaly sand, sandy shale, and shale predominate transmissivity for wells in the Marshall aquifer in Barry the Saginaw Formation in Barry County. In the county, the County ranges from approximately 310 to 38,100 ft2/day. Saginaw Formation is approximately 50 ft thick (Lilienthal, In Barry County, the upper portion of the Marshall aquifer 1974). The Saginaw Formation is not an important source of may yield fresh water, while the lower portion of the aquifer water in Barry County. may yield saline water or brine (Simms, 1988). Westjohn and The Parma Sandstone is often considered the basal unit Weaver (1996c) found the Marshall aquifer to supply fresh of the Saginaw Formation, although the stratigraphic rela‑ water in the majority of the county, excluding an area in the tionship is not clear between the Saginaw Formation, Parma northeast portion of the county where the water is saline. Sandstone, and Mississippian‑aged Bayport Limestone. The The Coldwater Shale underlies the Marshall Sandstone. Parma Sandstone is composed of medium‑ to coarse‑grained Calcareous shale, with interbeds of silty shale, and thin sand‑ sandstone, and is generally less than 100 ft thick (Cohee and stone comprise the Coldwater Shale in Barry County (Lilien‑ others, 1951). The Bayport Limestone is a fossiliferous, cherty thal, 1974). In the western portion of the State, the Coldwater limestone, often with interbedded sandstone. The Bayport Shale contains more carbonate than siltstone or sandstone Limestone has maximum thickness of 50 ft in the county and (Monnett, 1948). The Coldwater Shale is generally considered thins to the south, southwest, and west (Lilienthal, 1974). The a confining unit and ranges in thickness, from 500 to 1,300 ft, Bayport Limestone and Parma Sandstone appear to interfin‑ east to west across the State (Westjohn and Weaver, 1996b). ger throughout the Michigan Basin (Westjohn and Weaver, 1996a). Locally, both the Parma Sandstone and Bayport Limestone have been highly eroded (Lilienthal, 1974). These Bay County units are hydraulically connected, and together they form Bay County is in the eastern‑central portion of the Lower the Parma-Bayport aquifer (Westjohn and Weaver, 1996a). Peninsula of Michigan. The county is considered part of the Please note that due to the uncertainty of stratigraphic relation‑ Saginaw Lowlands (Westjohn and Weaver, 1998). Bay County ship between these units, in other reports this aquifer may be borders Saginaw Bay along a portion of its eastern side. The delineated differently. The Parma-Bayport aquifer only occurs Kawkalin-Pine, Pigeon-Wiscoggin, Tittabawasse, Saginaw, in the northeastern most edge of Barry County, and is 50 ft or and Lake Huron watersheds are included in the county on the less in thickness (Westjohn and Weaver, 1996a). It is not an north and central, southeast, northwest and southwest corners, important aquifer in the county. south‑central, and eastern portions of the county, respectively. The Michigan Formation underlies the Bayport Lime‑ The availability of ground water is a problem in areas of the stone. The Michigan Formation is composed of sandstone, county, due to low yields and mineral concentrations. Accord‑ shale, limestone, and occasional dolomite, which are all gener‑ ing to the February 2005 Wellogic database, approximately ally low in permeability. Gypsum and anhydrite are present in 37 percent of the wells in Bay County are completed in the the Michigan Formation. The Michigan Formation is consid‑ glacial deposits, and 59 percent in the bedrock units. There is ered a confining unit that separates the Parma-Bayport aquifer insufficient information to make this distinction for 4 percent from the underlying Marshall aquifer. In Barry County, the of the wells in the county. Glacial sand and gravel deposits, Michigan Formation ranges from 150 to 200 ft thick (Lilien‑ and sandstone from the Saginaw Formation form the two prin‑ thal, 1974). In Barry County, some wells have been screened cipal aquifers in the county. in the Michigan Formation. The water in these wells may yield In the Michigan Basin, glacial aquifers consist of sand high calcium and sulfate concentrations (Brewer, 1991). and gravel that are part of a sequence of Pleistocene glacial The Marshall Sandstone underlies the Michigan Forma‑ deposits. With the available information, glacial lithologies tion and is 350 to 400 ft thick in Barry County (Lilienthal, cannot be regionally correlated in the subsurface. This is likely 1974). The Marshall Sandstone consists of one or more due to the lateral and vertical heterogeneity of glacial deposits stratigraphically continuous permeable sandstones. The upper that resulted from a complex depositional history (Westjohn sandstone is a quartzarenite to sublitharenite that is referred to and others, 1994). Glacial deposits are up to 200 ft thick in as the Napoleon Sandstone Member. A shale, siltstone, and/or Bay County (Western Michigan University, 1981). In the carbonate layer separates the Napoleon Sandstone Member southern portion of the county, the greatest thickness of glacial from the underlying lower Marshall sandstone. The lower deposits is found in buried valleys. The buried valleys trend Marshall sandstone is comprised of two units. The upper unit northeast to southwest across Williams, Monitor, and Franken‑ is generally 50 to 125 ft of fine‑ to medium‑grained quartzare‑ lust Townships, and southeast to northwest in Merritt Town‑ nite to sublitharenite. At the base of the Marshall Sandstone is ship (Twenter and Cummings, 1985). Glacial deposits present a fine‑ to medium‑grained litharenite that ranges in thickness 10 Summary of Hydrogeologic Conditions by County for the State of Michigan in the county include lacustrine deposits and till. Lacustrine naw aquifer in Tuscola County is 2,540 ft2/day. Water from deposits consist of clay and silt‑dominated deposits, and also the Saginaw aquifer may be locally high in dissolved solids sand and gravel‑dominated deposits. Fine to medium‑grained (Twenter and Cummings, 1985). In Bay County, the Saginaw till is also present in the county (Farrand and Bell, 1982). In aquifer only yields freshwater in the northwestern portion of the southern portion of the county, generally, the uppermost 50 the county (Westjohn and Weaver, 1996c). to 150 ft of glacial deposits are composed of clay. Locally, the The Saginaw confining unit underlies the Saginaw aqui‑ clay may extend to the bedrock surface, contain thin interbeds fer. The Saginaw confining unit is approximately 50 to 100 of silt and fine‑grained sand, or contain thin to 60 ft thick lay‑ ft thick in the county, and is mostly shale, with thin layers of ers of sand and gravel. Wells tapping clay deposits supply very discontinuous sandstone, siltstone, limestone, and coal. The little, if any, water. In areas of the central‑eastern and south‑ permeable layers within the Saginaw confining unit appear to eastern of Williams Township, and in northeastern, northwest‑ be isolated from the regional ground‑water‑flow system (West‑ ern, and central‑western parts of Monitor Township, sand and john and Weaver, 1996a). gravel deposits are large and thick enough to be considered an aquifer (Twenter and Cummings, 1985). In Garfield Township, Stark and McDonald (1980) divided the glacial deposits into Benzie County three units: sand, clay, and sand and gravel. The uppermost Benzie County is in the northwestern portion of the unit is composed of proglacial, well‑sorted sand. The sand Lower Peninsula of Michigan. Sleeping Bear Dunes National unit ranges in thickness from 0 to 20 ft, and occurs in narrow Lakeshore is in the northwestern portion of the county. The ridges across the surface of the area. The clay unit is underlies Manistee, Betsie-Platte, and Lake Michigan watersheds drain the sand unit and ranges in thickness from 30 to 164 ft. The the county. According to the February 2005 Wellogic data‑ clay unit is predominately silt and clay, but also includes sand, base, approximately 97 percent of the wells in Benzie County gravel, and a clay and gravel mixture. Underlying the clay are completed in the glacial deposits, and 0 percent in the unit, is the sand and gravel unit, which ranges in thickness bedrock units. There is insufficient information to make this from 0 to 131 ft. The sand and gravel unit consists of predomi‑ distinction for 3 percent of the wells in the county. nately sand, gravel, and pebbles, but also consists of a minor In the Michigan Basin, glacial aquifers consist of sand amount of silt and clay. The sand and gravel unit is under and gravel that are part of a thick sequence of Pleistocene confined conditions (Stark and McDonald, 1980) and gener‑ glacial deposits. With the available information, glacial ally yields potable water (Twenter and Cummings, 1985). lithologies cannot be regionally correlated in the subsurface. However, water from some glacial wells have been reported to This is likely due to the lateral and vertical heterogeneity of be salty (Twenter and Cummings, 1985). glacial deposits that resulted from a complex depositional his‑ The Saginaw Formation underlies the glacial deposits and tory (Westjohn and others, 1994). Glacial deposits in Benzie forms the bedrock surface in Bay County. The Saginaw For‑ County range from 401 to 1,000 ft in thickness. However, mation is, on average, 330 ft thick, and composed of primarily the majority of the glacial deposits are between 401 and 800 shale, sandstone, and coal and may contain siltstone and lime‑ ft thick (Western Michigan University, 1981). In Sleeping stone. The most abundant unit in this sequence varies locally. Bear Dunes National Lakeshore, the glacial deposits range The beds are often discontinuous (Twenter and Cummings, from 700 to 900 ft thick (Handy and Stark, 1984). The glacial 1985). In a study area located in Garfield Township, the upper‑ deposits in the county include outwash, till and lacustrine most portion of the Saginaw Formation is an upper shale unit. deposits. The outwash deposits are mainly composed of sand This unit is composed of two types of shale: hard fissile shale and gravel. The majority of the outwash deposits occur in the with carbonaceous deposits and pyrite, and massive, soft silty central and eastern portions of the county (Farrand and Bell, shale. The upper shale unit also contains thin layers of coal, 1982). Till deposits are generally a poorly sorted mixture of sandstone, and siltstone. The main coal unit has an average clay, silt, sand, gravel, and rock fragments (Handy and Stark, thickness of 1.6 ft. In one area of Bay County, up to three beds 1984), which are generally found in moraines and till plains. of coal are present. Underneath the coal is the lower shale In Benzie County, the till is medium to coarse grained (Far‑ unit. This unit is primarily shale with thin layers of quartz‑rich rand and Bell, 1982). Moraines are present in the western and sandstone (Stark and McDonald, 1980). The Saginaw aquifer southeastern portions of the county. Glacial wells in Benzie is comprised of the permeable beds of sandstone within the County completed in till and/or outwash, according to the Saginaw Formation (Westjohn and Weaver, 1996a). Sand‑ Public Water Supply database, have estimated transmissivi‑ stone occurs at the base of the formation and is the principal ties from aquifer tests that range from approximately 1,280 bedrock aquifer. The sandstone is generally quartz‑rich, well to 64,940 ft2/day. The lacustrine deposits are coarse‑grained sorted, and fine‑grained and may have thin beds of shale or and occur in areas in the southeastern and western portions of clay in areas (Stark and McDonald, 1980). According to Stark the county (Farrand and Bell, 1982). According to the Public and McDonald (1980), transmissivity values for this layer Water Supply database, a well completed in lacustrine deposits are between 300 to 380 ft2/day, and the storage coefficient in the county had an estimated transmissivity from an aquifer is 0.0001. According to the Public Water Supply database, test of approximately 619 ft2/day. the estimated transmissivity from aquifer tests for the Sagi‑ County Summaries 11

In Sleeping Bear Dunes National Lakeshore, specific Berrien County ranges from approximately 3,125 to 23,590 capacity ranges from less than 1 and 50 gal/min/ft. Handy and ft2/day. Stark (1984) have identified areas of high specific capacity in Glacial deposits overlie the bedrock. The bedrock surface glacial wells at and near Sleeping Bear Dunes National Lake‑ is composed of the Coldwater Shale. The Coldwater Shale is shore. In Benzie County, this includes an area northeast of from 300 to 600 ft thick in Berrien County, and consists of Otter Lake. A specific capacity test was conducted near Loon primarily shale with some limestone. The Coldwater Shale Lake and values were determined to be 7.5 and 8.5 gal/min/ft generally yields small quantities of water that may be saline, (Handy and Stark, 1984). generally from the limestone in the unit (Stuart and Stallman, 1945). Berrien County Branch County Berrien County is located along the shore of Lake Michigan in the southwestern portion of the Lower Peninsula. Branch County is an area of 506 mi2 in the southern In addition to Lake Michigan, the Little Calumet-Galien, Lower Peninsula of Michigan. The St. Joseph watershed St. Joseph, Black-Macatawa, and Kankakee watersheds are drains the county. The topography ranges from flat till plains included in the county. Glacial aquifers are the primary source to rolling hills (Giroux and others, 1966). According to the of ground water in Berrien County. In general, the glacial February 2005 Wellogic database, approximately 83 percent aquifer is unconfined, except where clay‑rich, glacial‑lake of the wells in Branch County are completed in the glacial deposits act as a confining layer. According to the February deposits, and 13 percent in the bedrock units. There is insuf‑ 2005 Wellogic database, approximately 99 percent of the ficient information to make this distinction for 4 percent of the 5,260 water well logs in Berrien County are completed in the wells in the county. glacial deposits, and less than 1 percent in the bedrock units. With the available information, glacial lithologies cannot There is insufficient lithologic information to make this dis‑ be regionally correlated in the subsurface. This is likely due tinction for 4 percent of the water well logs in the county. to the lateral and vertical heterogeneity of glacial deposits that Post‑glacial deposits in Berrien County consist of eolian resulted from a complex depositional history (Westjohn and deposits, lacustrine deposits, and alluvium. Eolian deposits others, 1994). The glacial deposits are up to 500 ft thick in consist of primarily dune sand along the Lake Michigan Shore the county. Both the Erie and Saginaw lobes covered Branch (Stone, 2001). Alluvium is composed of sand and gravel and County during glacial times. The glacial deposits from the has a limited extent. Erie lobe, located in the southern portion of the county, are The thickness of glacial deposits varies within the county composed of fragments of limestone and other sedimen‑ and does not always correlate beneath the surface. Glacial tary rocks. The northern part of the county contains glacial deposits in Berrien County include deposits forming the Lake deposits from the Saginaw lobe, and is composed of remnants Border and Valparaiso moraines and range in thickness from of granites and other hard rocks. Glacial deposits include till, 40 to 400 ft (Leverett and Taylor, 1915; Bayless and others, outwash, and lacustrine deposits. Silty, clayey soils overlie the 2005). Leverett and Taylor (1915), state that the Valparaiso till deposits (Giroux and others, 1966). The till in the county moraine contains more sand and gravel in Michigan compared is medium to coarse grained (Farrand and Bell, 1982). Till to the till‑rich composition found in and . occurs in moraines and till plains. The morainal till is com‑ Geologists from the Geologic Mapping Coalition posed of boulders, gravel, and sand in a clay and silt matrix, (Bayless and others, 2005) describe the Valparaiso moraine and contains local lenses of outwash. The till in till plains in Berrien County as a series of interleaved glaciodeltas often has a higher amount of clay than the till in the moraines deposited as the glaciers retreated from the area. In places the and does not contain lenses of outwash. Outwash deposits in deltas are capped by thick clay‑rich till or lake‑bed deposits. the county are overlain by well‑drained, sandy soils. Outwash In the northern portion of the county, a more collapsed terrain, consists of sand and gravel. Lakes in the county are generally referred to as the Sodus terrain, with more kettle holes and surrounded by outwash deposits. The lacustrine deposits are “swell and swale” morphology is evident. The Lake Border composed of muck, silt, and clay, and are not considered to be moraine south of Benton Harbor is characterized by silty till aquifer material (Giroux and others, 1966). containing some small layers of fine to medium sand. The till In the Michigan Basin, glacial aquifers consist of sand generally is not an aquifer, but some water may be obtained and gravel that are part of a thick sequence of glacial deposits from the sand layers for domestic use. Northeast of Benton (Westjohn and others, 1994). Wells that are completed in the Harbor, a terrace terrain, referred to as the Paw Paw terrain, lenses of outwash within the till yield 10 to 40 gal/min and has an outwash sand aquifer that is overlain by a silty till. In provide moderate supplies of water. While, wells completed areas the sand aquifer is fairly extensive and may be under in till plains generally supply small quantities of water, with artesian conditions. According to the Public Water Supply yields from 0 to 15 gal/min. Wells in the outwash deposits database, the estimated transmissivity for glacial wells in supply moderate to large amounts of water, with yields up to 5,000 gal/min (Giroux and others, 1966). According to the 1 Summary of Hydrogeologic Conditions by County for the State of Michigan

Public Water Supply database, the estimated transmissivity for (Vanlier, 1966). The thickness of till varies in the county. Till sand and gravel glacial wells in Branch County ranges from is thickest in morainal areas. For example, till is up to 125 ft approximately 590 to 38,700 ft2/day. The glacial aquifer may thick in the Verona well field area, located in Battle Creek, yield water that is hard and contains high iron concentrations in a portion of the Kalamazoo Moraine. Thin layers of till (Giroux and others, 1966). may underlie outwash deposits (Grannemann and Twenter, Bedrock underlies the glacial deposits. The Coldwa‑ 1985). The Tekonsha Moraine consists of primarily sandy ter Shale forms the bedrock surface in Branch County. The till that also contains thin clay layers and discontinuous areas thickness of the Coldwater Shale ranges from 440 to 1,000 of sand and gravel (Chowdhury, 1999). Clay deposits and ft in the county. The Coldwater Shale is predominately blue sandy‑silty‑clay deposits have also been found in wells at the to gray shale and interbedded with thin lenses of limestone, Verona well field (Grannemann and Twenter, 1985). dolomite, and sandstone (Giroux and others, 1966). The In the Michigan Basin, glacial aquifers consist of sand Coldwater Shale is considered a confining unit in the majority and gravel that are part of a thick sequence of glacial deposits. of the State (Westjohn and Weaver, 1998). In Branch County, In Calhoun County, the glacial aquifer consists of primarily however, wells are locally completed in the Coldwater Shale. outwash and morainal deposits (Westjohn and others, 1994). These wells generally provide small quantities of water, from The estimated hydraulic conductivities in Calhoun County the lenses of sandstone or limestone, or from fractures. Yields are 110, 70, 30, and 15 ft/day for channel deposits, outwash, from these wells range from 2 to 3 gal/min to 10 to 30 gal/min. interlayered outwash and till, respectively (Grannemann and The water from the Coldwater Shale is often salty (Giroux and Twenter, 1985). According to the Public Water Supply data‑ others, 1966). base, the estimated transmissivity for glacial wells in Calhoun County ranges from approximately 3,210 to 13,500 ft2/day. Water from the glacial aquifer is generally hard to very hard Calhoun County and may contain excessive iron concentrations (Vanlier, 1966). Bedrock underlies the glacial deposits, and the bedrock Calhoun County is in the southern portion of the Lower surface of Calhoun County includes, from northeast to south‑ Peninsula of Michigan. The Upper Grand, Kalamazoo, and west, the Saginaw Formation, Bayport Limestone, Michigan St. Joseph watersheds drain the county in the northeastern, Formation, Marshall Sandstone, and Coldwater Shale. The central, and southwestern portions of the county. According bedrock units have a slight dip to the northeast (Vanlier, 1966). to the February 2005 Wellogic database, approximately 36 The Saginaw Formation consists of sandstone, shale, coal, percent of the wells in Calhoun County are completed in the and limestone. The most abundant unit in this sequence var‑ glacial deposits, and 58 percent in the bedrock units. There is ies locally. The Saginaw Formation yields more water from insufficient information to make this distinction for 6 percent sandstone at shallow depths and from thicker sandstone units of the wells in the county. (Vanlier, 1966). The Saginaw aquifer is comprised of the sand‑ With the available information, glacial lithologies cannot stones from the Saginaw Formation and ranges in thickness be regionally correlated in the subsurface. This is likely due from less than 100 to 370 ft in thickness in the State (Westjohn to the lateral and vertical heterogeneity of glacial deposits that and Weaver, 1996a). In Calhoun County, the Saginaw aquifer resulted from a complex depositional history (Westjohn and occurs in the northeastern corner of the county and the water others, 1994). Glacial deposits are up to 400 ft thick in the is fresh (Westjohn and Weaver, 1996c). The Saginaw confin‑ county (Western Michigan University, 1981). Glacial deposits ing unit underlies the Saginaw aquifer, and is composed of in Calhoun County include channel deposits, outwash, and primarily shale, but also contains beds of sandstone, siltstone, till. Alluvium and glacial‑stream deposits that are intercon‑ coal, and limestone. The permeable layers within the Sagi‑ nected are referred to as channel deposits. The thickness of naw confining unit appear to be isolated from the regional channel deposits in the Verona well field area ranges from 5 ground‑water‑flow system (Westjohn and Weaver, 1996a). to 37 ft. Channel deposits are generally coarser than outwash The Saginaw confining unit separates the Saginaw aqui‑ (Grannemann and Twenter, 1985). Sand and gravel outwash fer from the underlying Parma-Bayport aquifer. The Parma is abundant and interspersed throughout Calhoun County. Sandstone is often considered the basal unit of the Saginaw Although fine to coarse sand is found in the outwash deposits Formation, although the stratigraphic relationship is not at the Verona well field, most of the sand deposits in this area clear between the Saginaw Formation, Parma Sandstone, and are medium‑grained and coarser. The thickness of outwash Mississippian‑aged Bayport Limestone. The Parma Sandstone deposits varies in the county. In the Verona well field, the is composed of medium‑ to coarse‑grained sandstone, and maximum thickness of outwash is 100 ft. The majority of the is generally less than 100 ft thick (Cohee and others, 1951). till in the county is medium to coarse grained (Grannemann The Bayport Limestone is a fossiliferous, cherty limestone, and Twenter, 1985; Farrand and Bell, 1982). Till is a mixture often with interbedded sandstone and varies considerably of clay, silt, sand, gravel, and boulders. Till occurs in till plains in thickness from one area to another. The Bayport Lime‑ and moraines in Calhoun County. Moraines in the county stone and Parma Sandstone appear to interfinger throughout generally trend northwest to southeast and include the Kalam‑ the Michigan Basin (Westjohn and Weaver, 1996a). These azoo Moraine, Battle Creek Moraine, and Tekonsha Moraine units are hydraulically connected, and together they form the County Summaries 13

Parma-Bayport aquifer (Westjohn and Weaver, 1996a). The than siltstone or sandstone (Monnett, 1948). The impermeable Parma-Bayport aquifer is generally 100 to 150 ft thick where lithologies in the Coldwater Shale comprise the Coldwater it occurs within the Michigan Basin. Please note that due to confining unit. (Westjohn and Weaver, 1998). the uncertainty of stratigraphic relationship between these units, in other reports this aquifer may be delineated differ‑ ently. According to Vanlier (1966), the Parma-Bayport aquifer Cass County yields fresh water and may locally provide moderate water Cass County is in the southwestern Lower Peninsula of supplies where it is thick and solution cavities are present in Michigan. The southern portion of the county borders Indiana. the limestone. The county is in the St. Joseph watershed. According to the The Michigan Formation underlies the Bayport Lime‑ February 2005 Wellogic database, approximately 97 percent of stone, and is composed of sandstone, siltstone, shale, lime‑ the wells in Cass County are completed in the glacial depos‑ stone, and occasionally dolomite. Gypsum and anhydrite are its, and 0 percent in the bedrock units. There is insufficient also present in the Michigan Formation. Siltstone and sand‑ information to make this distinction for 3 percent of the wells stone layers that are discontinuous and interposed with lower in the county. permeability lithologies are considered the Michigan confin‑ With the available information, glacial lithologies cannot ing unit. The Michigan confining unit separates the Parma- be regionally correlated in the subsurface. This is likely due Bayport aquifer from the underlying Marshall aquifer. In the to the lateral and vertical heterogeneity of glacial deposits that county, the Michigan confining unit is approximately 100 ft resulted from a complex depositional history (Westjohn and thick (Westjohn and Weaver, 1996b). others, 1994). Glacial deposits range in thickness from 100 The Marshall Sandstone underlies the Michigan For‑ to 600 ft in the county, but are generally 200 to 400 ft thick mation. The Marshall Sandstone is predominately a fine to (Western Michigan University, 1981). The surficial glacial coarse‑grained sandstone with interbeds of siltstone, sandy deposits in Cass County are composed primarily of outwash, shale, and shale. In general, grain size decreases with depth ice‑contact outwash, and till. Outwash covers most of the in the Marshall Sandstone. Due to differential erosion, the county and is composed of well‑sorted sand and gravel depos‑ thickness of the Marshall Sandstone ranges from 0 to 200 ft its. Ice‑contact outwash, composed of poorly sorted sand and in the Verona well field area. In the same area, the Marshall gravel, is also present in the county. Moraines and till plains Sandstone has been divided into the upper sandstone, upper consist of coarse‑grained till (Farrand and Bell, 1982). siltstone, lower sandstone, lower siltstone, and shale. The In the Michigan basin, glacial aquifers consist of sand upper sandstone, often referred to as the Napoleon Sandstone and gravel that are part of a thick sequence of Pleistocene gla‑ Member, is considered to be an unconfined aquifer in areas, cial deposits (Westjohn and others, 1994). Kehew and others and is underlain by the upper siltstone that acts as a confining (1998) provide more detailed information about the east‑cen‑ layer. Below the upper siltstone is the lower sandstone and tral portion of the county. In this area, the thickness of glacial underlying lower siltstone, which form the lower confined deposits is approximately 279 ft. Here, the glacial deposits aquifer in the Marshall Sandstone. Shale underlies this lower consist of a shallow sand and gravel aquifer that is approxi‑ confined aquifer. mately 16 to 84 ft thick. Underneath this is an approximately Aquifer tests were performed on wells that obtain water 16 to 39 ft, generally continuous, layer of silt and clay‑rich from both the upper and lower portions of the Marshall Sand‑ till. Coarse‑grained glacial deposits generally underlie the thin stone at the Verona well field and the transmissivities ranged till layer in this area. Wells in the east‑central portion of Cass from 4,200 to 64,400 ft2/day (Lynch and Grannemann, 1997). County are generally screened above or below the silt and A pumping test was performed on the upper sandstone aquifer clay‑rich till layer (Kehew and others, 1998). According to the and a transmissivity of 320 ft2/day was estimated. A range of Public Water Supply database, the estimated transmissivity for transmissivity values, 0 to 15,000 ft2/day, were estimated for glacial wells in Cass County ranges from approximately 3,930 the upper sandstone aquifer from a constant hydraulic con‑ to 13,265 ft2/day. Bedrock underlies the glacial deposits, but is ductivity (150 ft/d) and thickness from 0 to 100 ft. A pumping not currently used for water supply. test was performed on the lower sandstone aquifer, and the transmissivity and storage coefficient was estimated at 25,000 ft2/day and 1.5 x 10‑5, respectively. A range of transmissivity Charlevoix County values, 3,000 to 27,000 ft2/day, were estimated for the lower sandstone aquifer from a constant hydraulic conductivity (550 Charlevoix County is in the northern Lower Peninsula. ft/d) and thickness from 5 to 50 ft (Grannemann and Twenter, Included in Charlevoix County are islands located to the 1985). The Marshall aquifer yields fresh water in Calhoun northwest in Lake Michigan. The Boardman-Charlevoix, County (Westjohn and Weaver, 1996c). Lake Michigan, and Cheboygan watersheds drain the county. The Coldwater Shale underlies the Marshall Sandstone According to the February 2005 Wellogic database, approxi‑ and is composed primarily of shale, but also includes layers mately 66 percent of the wells in Charlevoix County are com‑ of carbonate, siltstone, and sandstone. In the western portion pleted in the glacial deposits, and 18 percent in the bedrock of the State, the Coldwater Shale contains more carbonate 1 Summary of Hydrogeologic Conditions by County for the State of Michigan units. There is insufficient information to make this distinction formation of the Traverse Group is Bell Shale. Bell Shale has for 16 percent of the wells in the county. a maximum thickness of 80 ft in Michigan (Catacosinos and In the Michigan Basin, glacial aquifers consist of sand others, 2001). and gravel that are part of a thick sequence of Pleistocene The forms the bedrock surface of glacial deposits. With the available information, glacial the southern portion of Beaver Island (Milstein, 1987). In lithologies cannot be regionally correlated in the subsurface. the subsurface, the Detroit River Group consists of the Lucas This is likely due to the lateral and vertical heterogeneity of Formation, , and . glacial deposits that resulted from a complex depositional his‑ The is primarily composed of interlayered tory (Westjohn and others, 1994). The majority of the glacial carbonates and evaporates, with carbonate‑cemented, fine‑ to deposits in Charlevoix County range from 201 to 400 ft thick. medium‑grained, sandstone lenses are scattered near the basal However, the thickness of the glacial deposits span from 11 portion of the formation. The Lucas Formation is up to 1,050 to 800 ft in the county (Western Michigan University, 1981). ft in thickness in the Michigan Basin. In some areas, the water Glacial deposits include lacustrine, till, and outwash. Sand and from this formation is brine and may contain hydrogen sulfide. gravel lacustrine deposits are present along the western side The Amherstburg Formation underlies the Lucas Forma‑ of the county. Coarse‑grained till is present in the western and tion. The Amherstburg Formation is up to 300 ft thick and central portions of the county. Drumlins occur on the till plains is composed of fossiliferous limestone that is dolomitized in in the county and are composed of stony, sandy till (Mel‑ some areas. An upper sandstone is present in the formation horn, 1954). Coarse‑grained end moraines are predominantly in the western portion of the basin. The Sylvania Sandstone located on the surface of the eastern side of the county. Sand underlies the Amherstburg Formation. The Sylvania Sandstone and gravel outwash deposits are also abundant on the surface is composed of fine‑ to medium‑grained sandstone with quartz of the eastern side of the county (Farrand and Bell, 1982). In overgrowths interlayered with carbonate. Sylvania Sandstone addition, sand dunes may be found along the Lake Michigan has been eroded in areas of the basin (Gardner, 1974). shoreline in the county (Farrand and Bell, 1982). According to The underlies the the Public Water Supply database, the estimated transmissivity Group in Charlevoix County. The Bois Blanc Formation forms for glacial wells ranges from approximately 3,175 to 19,670 the bedrock surface of Gull and High Island, the southern por‑ ft2/day. tion Garden Island, and the northern portion of Beaver Island The bedrock surface is composed of the Ellsworth Shale, (Milstein, 1987). The Bois Blanc Formation is predominately Antrim Shale, and Traverse Group on the mainland, and the composed of carbonates, including limestone, dolomite with island bedrock surfaces are composed of the Detroit River chert, and dolomitic limestone. Portions of the formation are Group, Bois Blanc Formation, and Garden Island Forma‑ fossiliferous (Gardner, 1974). The formation is up to 360 ft tion (Milstein, 1987). According to the Public Water Supply thick (Catacosinos and others, 2001). database, the estimated transmissivity for bedrock wells ranges The underlies the Bois Blanc from approximately 120 to 35,700 ft2/day. Formation when both are present. Within the State, the Garden The Ellsworth Shale is composed of a gray to green‑ Island Formation has patchy occurrences (Gardner, 1974), ish‑gray shale. Ellsworth Shale generally contains some and ranges in thickness from 3 to 20 ft (Catacosinos and oth‑ dolomite and may also be composed of sandstone and siltstone ers, 2001). The Garden Island Formation contains dolomitic layers (Matthews, 1993). This unit is generally not consid‑ sandstone, sandy dolomite, and dolomite with chert nodules ered an aquifer. The Antrim Shale is composed of primarily (Gardner, 1974). The bedrock surface of Hog Island and the carbonaceous, black to dark‑gray shale. Near the base of the northern portion of Garden Island is composed of the Garden sequence, thin layers of gray shale and limestone may occur. Island Formation (Milstein, 1987). The major constituents in the Antrim Shale consist of quartz, illite, and kerogen. Kaolinite, chlorite, and pyrite also com‑ pose the Antrim Shale. The Antrim Shale has been found to Cheboygan County have bituminous limestone concretions up to 3 ft in diameter Cheboygan County is in the northern Lower Peninsula of (Matthews, 1993). The Antrim Shale can be up to 656 ft thick, Michigan. The Boardman-Charlevoix, Lone Lake-Ocqueoc, which occurs at the center of the Michigan Basin (Gutschick Cheboygan, Black, and Lake Huron watersheds are the surface and Sandberg, 1991). Like the Ellsworth Shale, this unit is not water drainages in the county. According to the February 2005 considered an aquifer. Wellogic database, approximately 84 percent of the wells in The underlying Traverse Group primarily consists of Cheboygan County are completed in the glacial deposits, and fossiliferous limestone. In the western portion of the basin, 9 percent in the bedrock units. There is insufficient informa‑ porous dolomite and anhydrite may be present. In the eastern tion to make this distinction for 7 percent of the wells in the portion of the basin, interlayers of shale are common. (Gard‑ county. ner, 1974). In Charlevoix County karst topography has been In the Michigan Basin, glacial aquifers consist of sand found to affect the ground‑water flow. Based on aquifer tests and gravel that are part of a thick sequence of Pleistocene gla‑ in Charlevoix County, the transmissivity of the limestone cial deposits. With the available information, glacial litholo‑ ranges from 13.4 to 5,347.2 ft2/day (Cathcart, 1982). The basal County Summaries 15 gies cannot be regionally correlated in the subsurface. This is the basal portion of the formation. The Lucas Formation is up likely due to the lateral and vertical heterogeneity of glacial to 1,050 ft in thickness in the Michigan Basin. In some areas, deposits that resulted from a complex depositional history the water from this formation is brine and may contain hydro‑ (Westjohn and others, 1994). The glacial deposits are up to gen sulfide. The Amherstburg Formation underlies the Lucas 600 ft thick in Cheboygan County. However, the majority of Formation. The Amherstburg Formation is up to 300 ft thick the glacial deposits are 201 to 400 ft thick (Western Michigan and is composed of fossiliferous limestone that is dolomitized University, 1981). The glacial deposits in the county consist of in some areas. An upper sandstone is present in the formation till, outwash, and lacustrine deposits. The northern and central in the western portion of the basin. The Sylvania Sandstone portions of the county consist of coarse‑grained lacustrine underlies the Amherstburg Formation. The Sylvania Sandstone deposits and areas of coarse‑grained till. Drumlins are present is composed of fine‑ to medium‑grained sandstone with quartz in the northeastern portion of the county, while eskers are overgrowths interlayered with carbonate. Sylvania Sandstone present in the southeastern portion. The southern portion of has been eroded in some areas of the basin (Gardner, 1974). the county is composed of outwash and ice‑contact outwash, The Bois Blanc Formation underlies the Grand River along with coarse‑grained till. The outwash deposits consist of Group in Emmet County. The Bois Blanc Formation is sand and gravel. In addition, sand dunes are present along the predominately composed of carbonates, including limestone, Lake Huron shoreline and interspersed along the northern and dolomite with chert, and dolomitic limestone. This forma‑ central portion of the county. A small area of peat and muck tion may be fossiliferous in places. The basal unit of the Bois occurs in the northwestern portion of the county (Farrand and Blanc formation is composed of a clastic or conglomerate Bell, 1982). layer (Gardner, 1974). In the northern portion of the county, The bedrock units underlie the glacial deposits through‑ bedrock wells are also used where the , out Cheboygan County. The bedrock surface, from south to Detroit River Group, and Bois Blanc Formation form the bed‑ north, is composed of the Antrim Shale, Traverse Group, rock surface. According to the Public Water Supply database, Dundee Limestone, Detroit River Group, and Bois Blanc the estimated transmissivity for a well completed in the Detroit Formation (Milstein, 1987). These layers were deposited River Group is approximately 6,523 ft2/day. during the Period. The Antrim Shale is composed of primarily carbonaceous, black to dark‑gray shale. Near the base of the sequence, thin layers of gray shale and limestone Chippewa County may occur. The major constituents in the Antrim Shale consist Chippewa County is in the eastern portion of the Upper of quartz, illite, and kerogen. Kaolinite, chlorite, and pyrite Peninsula of Michigan. The Betsy‑Chocolay, Tahquame‑ also compose the Antrim Shale. The Antrim Shale has been non, Waiska, Lake Superior, St. Marys, Carp‑Pine, and Lake found to have bituminous limestone concretions up to 3 ft in Huron watersheds are located in the county. According to the diameter (Matthews, 1993). The Antrim Shale may be up to February 2005 Wellogic database, approximately 48 percent 656 ft thick, which occurs at the center of the Michigan Basin of the wells in Chippewa County are completed in the glacial (Gutschick and Sandberg, 1991). Very few bedrock wells are deposits, and 48 percent in the bedrock units. There is insuf‑ located where the Antrim Shale forms the bedrock surface. ficient information to make this distinction for 4 percent of the The Traverse Group primarily consists of fossiliferous wells in the county. The glacial aquifer overlies the bedrock limestone. In the western portion of the basin, porous dolo‑ aquifers, except where glacial deposits are absent. The glacial mite and anhydrite may be present. In the eastern portion of aquifer may be locally confined. the basin, interlayers of shale are common. (Gardner, 1974). The thickness of glacial deposits ranges from 0 to greater The basal formation of the Traverse Group is the Bell Shale. than 150 ft in Chippewa County. Glacial deposits are discon‑ Bell Shale has a maximum thickness of 80 ft (Catacosinos and tinuous and thin in areas where bedrock elevations are high. others, 2001). Bedrock wells are located where the Traverse On the eastern side of the county, valleys in the bedrock have Group forms the bedrock surface. been filled with glacial sediments and may provide excellent Gardner (1974) divided the Dundee Limestone into the sources of groundwater. One bedrock valley is located from Roger City Member and underlying Reed City Member. The Whitefish Bay to Lake Huron following the Waiska and Pine Rogers City Member is composed of dolomitized limestone Rivers. Another extends from Brimley to Neebish Island along in the western portion of the state and impermeable limestone the Charlotte River. North of the Niagara escarpment, a third in the eastern portion of the state. The Reed City member is bedrock valley filled with glacial deposits follows the Munus‑ composed of porous dolomite underlain by anhydrite. The cong River. anhydrite is absent in the eastern portion of the state (Gardner, Aquifers in the glacial deposits consist largely of sands 1974). and gravels and vary regionally in thickness and permeabil‑ In the subsurface, the Detroit River Group consists of ity. Glacial deposits are heterogeneous in the subsurface and the Lucas Formation, Amherstburg Formation, and Sylvania cannot be regionally correlated (Westjohn and Weaver, 1994). Sandstone. The Lucas Formation is primarily composed of Glacial deposits in Chippewa County are composed of till, out‑ interlayered carbonates and evaporates with carbonate‑ce‑ wash, lacustrine sediments, and dunes. Most of the moraines mented, fine‑ to medium‑grained, sandstone lenses found near 1 Summary of Hydrogeologic Conditions by County for the State of Michigan in Chippewa County were originally deposited in glacial Lake to 600 ft thick in Chippewa County (Vanlier and Deutsch, Algonquin. Moderate supplies of water are possible from 1958a; Gillespie and Dumouchelle, 1989). Dolomite and sand‑ sand and gravel till found in moraines, predominately on the stone, along with shale comprise the Prairie du Chien Group eastern part of the county. Poor sources of water are found in (Catacosinos and others, 2001). The Munising Formation clay‑rich till primarily in the western part of the county. The is composed of well‑sorted, medium‑grained sandstone and moraines north of the Black River escarpment are composed friable, poorly sorted sandstone (Gillespie and Dumouchelle, of sand and gravel dominated till, while the moraines south of 1989). In the northern part of Chippewa County, near the the Black River escarpment are composed of clay dominated Sault Ste. Marie‑Sugar Island area, the Jacobsville Sandstone till or boulder and clay dominated till. Moraines that con‑ forms the bedrock surface sometimes beneath 300 ft of glacial tain large amounts of outwash yield large supplies of water. deposits, or at the surface, where glacial deposits are absent Till‑plain deposits are predominately till and often lie above (Vanlier and Deutsch, 1958a; Gillespie and Dumouchelle, the water table in Chippewa County. Till‑plain deposits are not 1989). The Jacobsville Sandstone is 120 to greater than 1,300 an adequate source of water in Chippewa County. The most ft thick (Vanlier and Deutsch, 1958a). The Jacobsville Sand‑ permeable glacial deposits are outwash plains and consist stone includes lenses of shale and conglomerate in primarily of sand and gravel (Vanlier and Deutsch, 1958a). In sandstone (Gillespie and Dumouchelle, 1989). The Jacobsville the Bay Mills Indian Community, located in the northeastern Sandstone is a productive aquifer in areas of Chippewa County portion of the county in the St. Marys watershed, an aquifer (Gillespie and Dumouchelle, 1989). In the Bay Mills Indian test was performed for a well in the sand and gravel aquifer. Community, the Jacobsville Sandstone locally yields saline The estimated transmissivity and storage coefficient are 4,300 water (Weaver, 1996). ft2/day and 0.0005, respectively (Weaver, 1996). Lacustrine sediments are not a sufficient source of water, but tend to overlie sand and gravel deposits from outwash or till creating a Clare County confining layer in these areas. Dune deposits may yield small Clare County is in the north‑central Lower Peninsula of supplies of water from shallow wells and also provide areas of Michigan. The Muskegon, Tittabawassee, and Pine watersheds recharge. Dune deposits occur throughout the county, but are drain Clare County. According to the February 2005 Wel‑ concentrated near Whitefish Bay. logic database, approximately 98 percent of the wells in Clare The bedrock aquifers underlie glacial deposits in most County are completed in the glacial deposits, and 0 percent in of Chippewa County. The bedrock units in the county dip the bedrock units. There is insufficient information to make to the south, toward the center of the Michigan Basin. As a this distinction for 2 percent of the wells in the county. The result, bedrock units in the county tend to thin to the north. southeastern portion of Clare County has fairly well‑drained (Vanlier and Deutsch, 1958a). The uppermost bedrock layers soils of medium texture. The remainder of the county gener‑ in Chippewa County are composed of limestone and dolomite, ally has sandy well‑drained soils (Michigan Water Resources including the Engadine Dolomite, Manistique Dolomite, Burt Commission, 1960). Bluff Formation, and . The first layer is In the Michigan Basin, glacial aquifers consist of sand approximately 500 ft thick, contains chert and gypsum, and and gravel that are part of a thick sequence of Pleistocene gla‑ solution cavities are present that provide areas of recharge cial deposits. With the available information, glacial litholo‑ and yield moderate amounts of water. Water derived from gies cannot be regionally correlated in the subsurface. This is the Cataract Formation tends to be of poor quailty due to the likely due to the lateral and vertical heterogeneity of glacial gypsum present in this layer. The bottom of the first layer deposits that resulted from a complex depositional history contains dolomitic shale at the base, which may confine the (Westjohn and others, 1994). Glacial deposits are 200 to 800 second bedrock layer composed of dolomite and limestone ft thick in Clare County (Western Michigan University, 1981). of the upper portion of the Richmond Group. This layer is The glacial deposits are composed of till and outwash. Fine to approximately 240 ft thick. Shale layers within the Richmond coarse‑grained till is interspersed on the surface of the county. Group may produce areas of lower permeability. Shale from The majority of the coarse‑grained till is near the center of the base of the Richmond Group and the Collingwood Forma‑ the county (Farrand and Bell, 1982). A morainic belt extends tion overlies the possibly confined limestone and dolomite across the county trending northeast to southwest (Michigan from the Trenton Formation and underlying Black River Water Resources Commission, 1960). Outwash is present on Formation, and is approximately 210 ft thick. The Trenton and the surface along the northwestern edge of the county (Far‑ Black River Formations contain lenses of sand in certain areas. rand and Bell, 1982). Outwash is highly permeable and is However, permeability generally decreases with depth in this composed of sand and gravel. Glacial wells in the county, layer. In the Rudyard area, water containing sulfur has come according to the Public Water Supply database, have estimated from the Trenton and Black River Formations. The base of the transmissivities from aquifer tests that range from approxi‑ is shale (Vanlier, 1959). The Prairie du mately 2,260 to 17,650 ft2/day. Bedrock underlies the glacial Chien Group, Munising Formation, and Jacobsville Sandstone deposits, but is not currently used for water supply. underlie the Black River Formation. The Prairie du Chien Group and underlying Munising Formation combined are 180 County Summaries 17

Clinton County Township. According to the Public Water Supply database, the estimated transmissivity for glacial wells ranges from approxi‑ Clinton County is in the south‑central Lower Peninsula mately 540 to 20,050 ft2/day. of Michigan. The Upper Grand watershed and the Maple The glacial deposits of Pleistocene age overlie Penn‑ watershed cross the southern and northern parts of the county. sylvanian [and Upper ] bedrock units in Ingham According to the February 2005 Wellogic database, approxi‑ County. Rocks of , [Lower and Middle] Jurassic, and mately 10 percent of the wells in Clinton County are com‑ age are missing (Mandle and Westjohn, 1989). pleted in the glacial deposits, and 86 percent in the bedrock The Jurassic “red beds” which separate rocks units. There is insufficient information to make this distinction from glacial deposits in some areas of the Lower Peninsula, for 4 percent of the wells in the county. Aquifers in the glacial are either entirely absent or only marginally present in the and bedrock aquifers provide water in Clinton County, but Tri‑County region, which consists of Ingham, Clinton, and generally are not as highly productive in the northwestern part Eaton Counties (Westjohn and others, 1994). The “red beds” (Vanlier and others, 1973). are often poorly consolidated or unconsolidated and consist of The glacial deposits in Clinton County range in thick‑ primarily clay, mudstone, siltstone, sandstone, shale and gyp‑ ness from less than 10 ft to over 300 ft. The glacial features in sum. The “red beds” are relatively impermeable and are con‑ Michigan are the result of ice advances during late sidered a confining unit. The “red beds” impede the vertical time (35,000 to 10,000 years before present). Glacial deposits flow of water between glacial and bedrock aquifers (Westjohn are of three principal types: 1) a well‑sorted mixture of silt, and others, 1994). sand, and gravel, such as valley outwash, outwash plains, Discontinuous lenses of sandstone, shale, coal, and lime‑ eskers, kames, and buried outwash, deposited by streams stone in the Pennsylvanian bedrock units have been formally of melt water draining from glaciers, 2) a layered sequence subdivided into two formations. The uppermost massive, of silt, sand, and clay deposited in glacial lakes, and 3) an coarse‑grained sandstones form the ; unsorted mixture of clay, silt, sand, gravel, and boulders, such all remaining Pennsylvanian rocks are considered part of the as till, deposited directly from the melting ice (Vanlier and underlying Saginaw Formation (Mandle and Westjohn, 1989). others, 1973). None of these deposits are regionally continu‑ The Grand River Formation, although removed by erosion ous (Mandle and Westjohn, 1989). after deposition over a large part of Clinton County, ranges Glacial deposits are the uppermost aquifer in Clinton in thickness up to 125 feet thick in some parts of the county County. Ground‑water flow in the glacial deposits is gener‑ (Vanlier and others, 1973). These assignments between forma‑ ally from south to north, away from topographic divides and tions are somewhat uncertain, however, because no lithologic towards surface‑water bodies. Aquifers in the glacial deposits differences or stratigraphic horizons mark a change from one are composed of coarse alluvial and outwash materials. Long, formation to the next (Westjohn and Weaver, 1996a). The narrow ridges of sand and gravel, called eskers, are present Pennsylvanian bedrock unit ranges in thickness from less than in parts of Clinton County, primarily in the southeast. Hills 50 to over 400 ft in Clinton County. or mounds of sand and gravel, called kames, are also pres‑ The basal part of the Pennsylvanian Saginaw Forma‑ ent primarily in the southeast part of Clinton County. Both tion is considered to be the Parma Sandstone although the of these may provide water to wells in the area (Vanlier and stratigraphic relationship is not clear between the Saginaw others, 1973). Buried outwash deposits were formed as areas Formation, Parma Sandstone, and the underlying Bayport of outwash deposited by a preceding glacier were covered by a Limestone. The Parma Sandstone is composed of medium‑ to layer of till deposited during a later glacial advance. The most coarse‑grained sandstone and is generally less than 100 ft extensive area of buried outwash deposits is in the southern thick (Cohee and others, 1951). Interpretation of geophysi‑ part of Clinton County. These areas of buried outwash are cal logs indicates that the lower part of the Pennsylvanian a potential source of water to wells; however, most wells in rock sequence is predominantly shale, whereas the upper part these areas are completed in bedrock aquifers because of the is predominantly sandstone. Thus, the Pennsylvanian rocks better quality water available. Lake plain deposits, consisting younger than the Parma Sandstone can be divided into a lower of beds of clay, silt, and sand deposited in glacial lakes, under‑ confining unit and an upper sandstone aquifer (Westjohn and lie parts of Clinton County; however, these deposits generally Weaver, 1996a). are thin and in most places and are not a source of water to The Saginaw aquifer is in the water‑bearing sandstones in wells (Vanlier and others, 1973). Till is present over much the Grand River and Saginaw Formations. Most ground‑water of the county and is generally not a source of water to wells flow in the Saginaw aquifer is from south to north, although a (Vanlier and others, 1973). Locally the till may include thin small amount is toward local pumping centers. The Saginaw beds of sand and gravel that may be a source of water or may aquifer is recharged principally by leakage from the glacial overlies bodies of sand and gravel that may yield moderate deposits. Ground water also discharges locally from bed‑ to large supplies of water (Vanlier and others, 1973). The till rock to the glacial deposits beneath valleys of major streams underlying the Flint moraine in the southern part of the Elsie (Holtschlag and others, 1996). The Grand River and Saginaw area is of greater permeability and includes more beds of sand Formations act as a single hydrologic unit, so the chemical and gravel than the till deposits in the northern part of Duplain characteristics of water in these formations are very similar. 1 Summary of Hydrogeologic Conditions by County for the State of Michigan

Nearly all wells tapping these formations yield water that tory (Westjohn and others, 1994). The majority of the glacial is suited to household needs. The water is generally hard or deposits in Crawford County range from 401 to 600 ft thick. very hard and contains iron, although, in some localities, the However, the thickness of the glacial deposits spans from 201 Saginaw Formation yields soft water (Vanlier and others, to 1,000 ft thick in the county (Western Michigan University, 1973). Analyses of aquifer‑test data indicate a wide range 1981). The majority of Crawford County is composed of sand of transmissivities within the Saginaw aquifer. Wood (1969) and gravel outwash deposits. Poorly sorted, ice‑contact out‑ reported that pumping tests indicated a relatively constant wash deposits are also scattered through the county. A small permeability of the sandstone in the Saginaw Formation of area, in the central eastern portion of the county, is composed about 100 gpd/ft2 (13 ft/day). The permeability of the shale of silt and clay lacustrine deposits (Farrand and Bell, 1982). is more variable, ranging from 0.01 to 1.0 gpd/ft2 (0.001 to Glacial wells in the county, according to the Public Water 0.13 ft/day) (Wood, 1969). Transmissivities that range from Supply database, have estimated transmissivities from aquifer 130 to 2,700 ft2/day were reported for the Saginaw aquifer for tests that range from approximately 7,060 to 12,500 ft2/day. the three‑county area of Clinton, Ingham, and Eaton Counties Bedrock underlies the glacial deposits, but it is not currently by Vanlier and Wheeler (1968). This range in transmissivi‑ used for water supply. ties reflects variations in the total thickness of the sandstone beds in the formation and variations in the permeability of the sandstone. According to the Public Water Supply database, the Delta County estimated transmissivity for the Saginaw aquifer ranges from Delta County is in the central portion of the Upper approximately 450 to 3,890 ft2/day. Measured porosities and Peninsula. The Cedar‑Ford, Escanaba, Tacoosh‑Whitefish, matrix‑controlled vertical hydraulic conductivities range from Fishdam‑Sturgeon, Manistique, and Lake Michigan water‑ 4 to 34 percent and 0.0001 to 55 ft/day, respectively (Westjohn sheds are included in the county. According to the February and Weaver, 1996a). 2005 Wellogic database, approximately 7 percent of the wells Underlying the Saginaw Formation are beds of Mis‑ in Delta County are completed in the glacial deposits, and 88 sissippian age – the Bayport Limestone and the Michigan percent in the bedrock units. There is insufficient informa‑ Formation. The Bayport Limestone is a fossiliferous, cherty tion to make this distinction for 5 percent of the wells in the limestone, often with interbedded sandstone and varies con‑ county. Generally, the glacial aquifer is unconfined. However, siderably in thickness from one area to another. The Bayport in areas where lenses of clay are present in the glacial depos‑ Limestone and Parma Sandstone appear to interfinger through‑ its, the aquifer may become semi‑confined or confined. The out the Michigan Basin. These units are stratigraphically con‑ occurrence of glacial wells increases near the center of the tinuous and hydraulically connected, and together they form county, in a cluster that trends northwest to southeast. the Parma‑Bayport aquifer (Westjohn and Weaver, 1996a). With the available information, glacial lithologies cannot Please note that due to the uncertainty of stratigraphic relation‑ be regionally correlated in the subsurface. This is likely due ship between these units, in other reports this aquifer may be to the lateral and vertical heterogeneity of glacial deposits that delineated differently. The Michigan Formation is composed resulted from a complex depositional history (Westjohn and primarily of shale but includes beds of sandstone, limestone, others, 1994). Aquifers in the glacial deposits consist largely and gypsum (Vanlier and others, 1973). Both the Bayport and of sands and gravels, and vary regionally in thickness and Michigan Formations yield saline water where they are over‑ permeability. The glacial deposits range in thickness from 0 lain by the Saginaw Formation. to greater than 200 ft in Delta County. The glacial deposits are thin and discontinuous in the southern and western portions Crawford County of the county, and thicker in the northeastern part (Sinclair, 1960). The glacial deposits in Delta County are composed of Crawford County in the central‑northern portion of the till, outwash, and lacustrine deposits. Discontinuous exten‑ Lower Peninsula of Michigan. The Muskegon, Manistee, and sions of the Newberry and Munising Moraines exist in the Au Sable watersheds cross Crawford County. According to the northeastern part of Delta County. These moraines are pre‑ February 2005 Wellogic database, approximately 99 percent dominantly composed of sand‑ and gravel‑rich till, however, of the wells in Crawford County are completed in the glacial the clay content increases to the south. Generally, the moraines deposits, and 0 percent in the bedrock units. There is insuf‑ in the northeastern portion of the county are above the water ficient information to make this distinction for 1 percent of the table. A moraine extends north to south along the western side wells in the county. of the county and is composed of a thin layer of coarse till. A In the Michigan Basin, glacial aquifers consist of sand segment of Cooks Moraine in T41N, R18W, consists primar‑ and gravel that are part of a thick sequence of Pleistocene ily of silty sand; however, the till ranges from clay to boulder glacial deposits. With the available information, glacial size. In the northeastern portion of Delta County large deposits lithologies cannot be regionally correlated in the subsurface. of sand and gravel outwash are present. Lacustrine deposits This is likely due to the lateral and vertical heterogeneity of are present primarily in the southeastern portion of the county, glacial deposits that resulted from a complex depositional his‑ and are primarily composed of sand with some clay and silt. In County Summaries 19 addition, wetlands often overlay the lacustrine deposits. Dune igneous Precambrian rocks that are too deep and impermeable sand deposits can be found throughout the county, and often to supply water (Sinclair, 1960). act as areas of ground‑water recharge (Sinclair, 1960). The bedrock units underlie the glacial deposits through‑ out the county except where the bedrock units . The Dickinson County units that form the bedrock surface generally subcrop trending Dickinson County is in the western Upper Peninsula of southwest to northeast. The youngest layers form the bed‑ Michigan. The Michigamme, Menominee, Cedar‑Ford, and rock surface in the southeastern portion of the county and get Escanaba watersheds drain through the county. An area in the progressively older to the northwest. The bedrock layers thin northwest portion of the county is drained by the Michigamme to the northwest, because individual bedrock layers dip toward River. The Menominee River traces the southern border of the southeast. The estimated transmissivity values for the bed‑ the county, and drains the central and southern portions of rock aquifers ranges between 45 and 800 ft2/day. These values the county via the Pine and Sturgeon Rivers. The Ford and were calculated using specific capacity data (Sinclair, 1960). the West Branch of the Escanaba River drain the remaining From youngest to oldest, the Engadine Dolomite, northern part of the county (Hendrickson and Doonan, 1966). Manistique Dolomite, Burnt Bluff Formation, and Cataract According to the February 2005 Wellogic database, approxi‑ Formation form the uppermost bedrock layers. The Engadine mately 45 percent of the wells in Dickinson County are com‑ Dolomite is not aerially extensive, and is approximately 10 ft pleted in the glacial deposits, and 53 percent in the bedrock thick where present. The Engadine Dolomite is generally not units. There is insufficient information to make this distinc‑ considered a source of water in Delta County because of its tion for 2 percent of the wells in the county. Hendrickson and very limited extent. The Manistique Dolomite contains chert, Doonan (1966) identify three aquifers within the county: the and is up to 150 ft in thickness. The Burnt Bluff Formation is glacial aquifer, the Paleozoic aquifer, and the Precambrian composed of dolomite that is up to 250 ft thick. This bedrock aquifer. It is not clear whether these aquifers are confined unit typically yields moderate amounts of water, especially or unconfined. However, the glacial aquifer appears to be in the Garden Peninsula. The Cataract Formation is approxi‑ unconfined except where the glacial deposits underlie swamp mately 250 ft thick, and is primarily dolomite, with shale deposits. In these areas, the glacial aquifer is semi‑confined and gypsum. Shale may retard the flow of water in areas, or confined. In general, ground water in Dickinson County is while moderate yields of water are due to the solution cavi‑ hard, with high iron content in some areas (Hendrickson and ties formed from gypsum. Estimated transmissivity for the Doonan, 1966). Cataract Formation ranges between 170 and 880 ft2/day. Water Post‑glacial swamp deposits consist of peat and muck derived from the Cataract Formation is usually poor quality and are found in lowland areas near streams, lakes, and former as a result of dissolution of gypsum in the formation (Sinclair, lakes in areas of Dickinson County. The glacial aquifer ranges 1960). The base of the Cataract Formation contains dolomitic in thickness from 0 to 100 ft. Most wells in Dickinson County shale that may act as a confining layer (Vanlier and Deutsch, acquire water from sand‑and‑gravel outwash or kame depos‑ 1958a). its. Outwash is primarily composed of stratified sand and The Richmond Group underlies the Cataract Formation. gravel with some silt and clay. Stratified gravel, sand, silt, and The Richmond Groups is composed of limestone and dolomite clay also compose kame deposits, along with large areas of with some shale. Few fractures in the limestone and dolo‑ unsorted till. The sand and gravel, in the kame deposits, gener‑ mite, and the presence of shale hinder the flow of water in the ally occurs as discontinuous lenses. Wells completed in till Richmond Group. The lower portion of the Richmond Group, usually supply small amounts of water. Till generally occurs and the underlying Collingwood Formation, form a shale layer in moraines and till plains and is composed of poorly sorted that ranges in thickness from 130 to 300 ft. This may act as a clay, silt, sand, and stones. End moraines in the county contain confining layer. Limestone and dolomite from the Trenton and areas of sandy till, which also contain lenses of sand and Black River Formations underlies the Collingwood Formation. gravel. These areas are capable of supplying larger amounts of Estimated transmissivity for the Trenton and Black River For‑ water. The estimated transmissivity of the glacial aquifer was mations ranges between 45 and 370 ft2/day. The western por‑ calculated using the specific capacity values of Hendrickson tion of the county uses this aquifer as a main source of water, and Doonan (1966), and ranges from approximately 98 to but the yield from these wells is often low (Sinclair, 1960). 3,948 ft2/day. According to the Public Water Supply database, The base of the Black River Formation is shale that may act the estimated transmissivity for glacial wells ranges from as a confining layer (Vanlier, 1959). Below this lies sandstone approximately 1,870 to 8,640 ft2/day. from the Au Train Formation (Hermansville) and Munising Kingsford and Iron Mountain are located in the south‑ Sandstone, which may be hydraulically connected (Sinclair, western corner of the county in Breitung Township. Glacial 1960). The estimated transmissivity for well completed in aquifers supply the majority of ground water in the area, and the Au Train Formation and Munising Sandstone are 450 and ground water flows to the west or southwest. In the Kingsford 700 ft2/day, respectively. The Jacobsville Sandstone may not and Iron Mountain area, the thickness of the glacial depos‑ be present in Delta County. Below this, are metamorphic and its ranges between 0 and 480 ft. In this area, generally two 20 Summary of Hydrogeologic Conditions by County for the State of Michigan glacial aquifers are present (Luukkonen and Westjohn, 2001). northern, western, and southern parts of the county. Accord‑ The upper terrace sand‑and‑gravel unit, which is 0 to 160 ft ing to the February 2005 Wellogic database, approximately thick, is primarily composed of fine‑ to medium‑grained sand, 18 percent of the wells in Eaton County are completed in the along with variable amounts of silt and gravel (Engineering glacial deposits, and 69 percent in the bedrock units. There is for Earth, Water, and Air Resources, Inc, 1987). The upper insufficient information to make this distinction for 13 percent terrace unit has an estimated transmissivity between 9,100 of the wells in the county. In northwestern Eaton County water and 11,400 ft2/day. Underlying the upper terrace unit is a resources are limited regionally, but are abundant locally. confining unit that is composed of lacustrine clay and silt and Aquifers in the glacial deposits are the primary source of water eolian silt. In the north and west of the Kingsford and Iron in the northwest; however, aquifers in the Saginaw and Michi‑ Mountain area the confining unit is primarily composed of gan Formations provide water to some wells, but generally are silt and fine‑grained sand (Luukkonen and Westjohn, 2001). not highly productive (Vanlier and others, 1973). In north‑ The confining unit ranges from 0 to 150 ft thick, and is absent eastern Eaton County, the principal aquifers are in the glacial in isolated areas in Kingsford. Where the confining unit is deposits and the Saginaw Formation. These aquifers will yield absent, the upper terrace and lower outwash units form one moderate to large supplies in some areas, but are not highly aquifer. The lower outwash sand‑and‑gravel unit underlies the productive over much of the area (Vanlier and others, 1973). confining unit where it is present, and ranges between 0 and In southwestern Eaton County, the principal aquifers are in 237 ft in thickness. The lower outwash unit consists of fine‑ to the glacial deposits and the Marshall Formation. The Saginaw, coarse‑grained sand that is moderately well sorted with silt Bayport, and Michigan Formations, which are tapped by some and gravel lenses or layers (Engineering for Earth, Water, household wells, generally are not sources of major water sup‑ and Air Resources, Inc, 1987). Luukkonen and Westjohn plies (Vanlier and others, 1973). In southeastern Eaton County, (2001) interpreted the outwash sand‑and‑gravel aquifer to be water resources are moderately abundant. The principal aqui‑ unconfined or confined in areas dependent upon the position fers of this part of the county are in the glacial deposits, the of the water table. The lower outwash unit has an estimated Saginaw Formation, and, in the southern edge of the area, the transmissivity between 2,800 and 8,700 ft2/day, and for one Michigan Formation (Vanlier and others, 1973). well in Iron Mountain as much as 24,100 ft2/day. Lodgement The glacial deposits in Eaton County range in thickness till or the Vulcan Iron Formation underlies the lower outwash from 0 to over 300 ft. The glacial deposits are absent in a unit. These units range from 0 to 250 ft thick (Luukkonen and small area of the north central part of Eaton County. The gla‑ Westjohn, 2001). cial features in Michigan are the result of ice advances during Bedrock underlies glacial deposits in the county, except late Wisconsin time (35,000 to 10,000 years before present). where bedrock is exposed at the surface. The bedrock consists Glacial deposits are of three principal types: 1) a well‑sorted of Paleozoic and Precambrian rocks. The Paleozoic rocks mixture of silt, sand, and gravel, such as valley outwash, form the bedrock surface primarily in the eastern portion of outwash plains, eskers, kames, and buried outwash, deposited the county. Isolated subcrops are present in other areas in by streams of melt water draining from glaciers, 2) a layered the county. The Paleozoic aquifer supplies small to moderate sequence of silt, sand, and clay deposited in glacial lakes, and water yields. The Paleozoic aquifer consists of Ordovician 3) an unsorted mixture of clay, silt, sand, gravel, and boulders, and Cambrian dolomites and sandstones (Hendrickson and such as till, deposited directly from the melting ice (Vanlier Doonan, 1966). The estimated transmissivity of the Paleozoic and others, 1973). None of these deposits are regionally con‑ aquifer was calculated using the specific capacity values of tinuous (Mandle and Westjohn, 1989). Hendrickson and Doonan (1966) and ranges from approxi‑ Glacial deposits are the uppermost aquifer in Eaton mately 43 to 3,440 ft2/day. County. Ground‑water flow in the glacial deposits is gener‑ The Precambrian rocks subcrop mainly in the central and ally from south to north, away from topographic divides and western portion of the county. Small amounts of water may towards surface‑water bodies. Aquifers in the glacial deposits be obtained from shallow wells in Precambrian metamorphic are composed of coarse alluvial and outwash materials. An and igneous rocks. Fractures, and therefore the permeability of outwash plain covering several square miles is just east of the Precambrian rocks, decrease with depth (Hendrickson and Eaton Rapids. In the northern part of this plain, the sand and Doonan, 1966). The estimated transmissivity of the Precam‑ gravel beds may yield large supplies of water to wells. A brian aquifer was calculated using the specific capacity values smaller outwash plain lies just east of Charlotte (Vanlier and of Hendrickson and Doonan (1966) and ranges from 13 to others, 1973). Long narrow ridges of sand and gravel, called 1,289 ft2/day. eskers, are present in Eaton County. Buried outwash deposits were formed as areas of outwash deposited by a preceding glacier were covered by a layer of till deposited during a later Eaton County glacial advance. The most extensive area of buried outwash deposits are in the northeastern part of Eaton County. These Eaton County is in the south‑central Lower Peninsula areas of buried outwash are a potential source of water to of Michigan. The Upper Grand watershed, the Thornapple wells; however, most wells in these areas are completed in watershed, and the Kalamazoo watershed drain through the bedrock aquifers because of the better quality water available. County Summaries 1

Till is present over much of the county and is generally not a County. The Saginaw aquifer is recharged principally by leak‑ source of water to wells. Locally the till may include thin beds age from the glacial deposits. Ground water also discharges of sand and gravel that are a source of water or may overlies locally from bedrock to the glacial deposits beneath valleys of bodies of sand and gravel that may yield moderate to large major streams (Holtschlag and others, 1996). The Grand River supplies of water (Vanlier and others, 1973). According to the and Saginaw Formations act as a single hydrologic unit, so the Public Water Supply database, the estimated transmissivity for chemical characteristics of water in these formations are very glacial wells in the county ranges from approximately 615 to similar. Nearly all wells tapping these formations yield water 127,000 ft2/day. that is suited to household needs. The water is generally hard The glacial deposits of Pleistocene age overlie Pennsylva‑ or very hard and contains iron, although, in some localities, nian [and Upper Jurassic] and Mississippian bedrock units in the Saginaw Formation yields soft water (Vanlier and others, Eaton County. Rocks of Triassic, [Lower and Middle] Jurassic, 1973). Analyses of aquifer‑test data indicate a wide range and Cretaceous age are missing (Mandle and Westjohn, 1989). of transmissivities within the Saginaw aquifer. Wood (1969) The Jurassic “red beds” which separate Pennsylvanian rocks reported that pumping tests indicated a relatively constant from glacial deposits in some areas of the Lower Peninsula, permeability of the sandstone in the Saginaw Formation of are either entirely absent or only marginally present in the about 100 gpd/ft2 (13 ft/day). The permeability of the shale Tri‑County region, which consists of Ingham, Clinton, and is more variable, ranging from 0.01 to 1.0 gpd/ft2 (0.001 to Eaton Counties (Westjohn and others, 1994). The “red beds” 0.13 ft/day) (Wood, 1969). Transmissivities that range from are often poorly consolidated or unconsolidated and consist of 130 to 2,700 ft2/day were reported for the Saginaw aquifer for primarily clay, mudstone, siltstone, sandstone, shale, and gyp‑ the three‑county area of Clinton, Ingham, and Eaton Counties sum. The “red beds” are relatively impermeable and are con‑ by Vanlier and Wheeler (1968). This range in transmissivi‑ sidered a confining unit. The “red beds” impede the vertical ties reflects variations in the total thickness of the sandstone flow of water between glacial and bedrock aquifers (Westjohn beds in the formation and variations in the permeability of the and others, 1994). sandstone. According to the Public Water Supply database, Discontinuous lenses of sandstone, shale, coal, and lime‑ the estimated transmissivity for wells completed in the Grand stone in the Pennsylvanian bedrock units have been formally River and Saginaw Formations in Eaton County ranges from subdivided into two formations. The uppermost massive, approximately 840 to 3,240 ft2/day. Measured porosities and coarse‑grained sandstones form the Grand River Formation; matrix‑controlled vertical hydraulic conductivities range from all remaining Pennsylvanian rocks are considered part of the 4 to 34 percent and 0.0001 to 55 ft/day, respectively (Westjohn underlying Saginaw Formation (Mandle and Westjohn, 1989). and Weaver, 1996a). In Eaton County, erosion removed most of the Grand River Underlying the glacial deposits in the western and Formation, and as a result only a few large remnants remain southern part of Eaton County are beds of Mississippian age (Vanlier and others, 1973). These assignments between forma‑ – the Bayport Limestone, the Michigan Formation, and the tions are somewhat uncertain, however, because no lithologic Marshall Sandstone. The Bayport Limestone is a fossilifer‑ differences or stratigraphic horizons mark a change from one ous, cherty limestone, often with interbedded sandstone and formation to the next (Westjohn and Weaver, 1996a). The varies considerably in thickness from one area to another. The Pennsylvanian bedrock unit ranges in thickness from 0 to over Bayport Limestone and Parma Sandstone appear to interfinger 400 ft and is absent in the extreme western and southern parts throughout the Michigan Basin. These units are hydrauli‑ of Eaton County. cally connected, and together they form the Parma‑Bayport The basal part of the Pennsylvanian Saginaw Forma‑ aquifer (Westjohn and Weaver, 1996a). Please note that due tion is considered to be the Parma Sandstone although the to the uncertainty of stratigraphic relationship between these stratigraphic relationship is not clear between the Saginaw units, in other reports this aquifer may be delineated differ‑ Formation, Parma Sandstone, and the underlying Bayport ently. The Michigan Formation is composed primarily of Limestone. The Parma Sandstone is composed of medium‑ to shale but includes beds of sandstone, limestone, and gypsum coarse‑grained sandstone and is generally less than 100 ft (Vanlier and others, 1973). Siltstone and anhydrite layers that thick (Cohee and others, 1951). Interpretation of geophysi‑ are discontinuous and interposed with lower permeability cal logs indicates that the lower part of the Pennsylvanian lithologies are considered the Michigan confining unit. This rock sequence is predominantly shale, whereas the upper part unit separates the Parma‑Bayport aquifer from the underlying is predominantly sandstone. Thus, the Pennsylvanian rocks Marshall Sandstone. The Marshall Sandstone consists of a younger than the Parma Sandstone can be divided into a lower sequence of sedimentary rocks between the Coldwater Shale confining unit and an upper sandstone aquifer (Westjohn and and the Michigan Formation. The Marshall aquifer consists of Weaver, 1996a). one or more stratigraphically continuous permeable sand‑ The Saginaw aquifer is in the water‑bearing sandstones in stones. In areas where the Marshall aquifer consists of two or the Grand River and Saginaw Formations. Most ground‑water more sandstones, these permeable strata typically are sepa‑ flow in the Saginaw aquifer is from south to north, although a rated by beds of siltstone, shale and (or) carbonate (Westjohn small amount is toward local pumping centers. The Saginaw and Weaver, 1996b). Both the Bayport and Michigan Forma‑ aquifer is absent along the western and southern parts of Eaton tions yield saline water where they are overlain by the Sagi‑  Summary of Hydrogeologic Conditions by County for the State of Michigan naw Formation. In southwestern Eaton County, the Bayport mation. The Antrim Shale is composed of primarily carbona‑ Limestone is overlain by glacial deposits and is a source of ceous, black to dark‑gray shale. Near the base of the sequence, fresh water to household wells. Sandstone beds in the forma‑ thin layers of gray shale and limestone may occur. The Antrim tion supply many of these wells, although some limestone Shale is not considered an aquifer in Emmet County. The beds are also water producing (Vanlier and others, 1973). The major constituents in the Antrim Shale consist of quartz, illite, Michigan Formation is a source of fresh water in southwestern and kerogen. Kaolinite, chlorite, and pyrite also compose and western Eaton County where it is overlain directly by the the Antrim Shale. The Antrim Shale has been found to have glacial deposits or by the Bayport Limestone. The quality of bituminous limestone concretions up to 3 ft in diameter (Mat‑ water yielded by the formation varies considerably. The Mar‑ thews, 1993). The Antrim Shale can be up to 650 ft thick at the shall Sandstone yields potable water in southwestern Eaton center of the Michigan Basin (Gutschick and Sandberg, 1991). County and supplies water to municipal and household wells. The Traverse Group underlies the Antrim Shale. The In some areas the Marshall Sandstone yields fresh water where Traverse Group primarily consists of fossiliferous limestone. the overlying Michigan Formation yields saline water (Van‑ In some areas the Traverse Group has been highly fractured lier and others, 1973). According to the Public Water Supply which leads to local areas of very high permeability within database, the estimated transmissivity for a well completed that unit. In the western portion of the Michigan Basin, porous in the Marshall Sandstone in Eaton County is approximately dolomite and anhydrite may be present. In the eastern portion 1,885 ft2/day. Analysis of aquifer tests of the Marshall aquifer of the basin, interlayers of shale are common. (Gardner, 1974). in Muskegon, Genesee, and Eaton Counties indicate a small The basal formation of the Traverse Group is the Bell Shale. range of transmissivities (10 to 37 ft2/day) and hydraulic con‑ Bell Shale has a maximum thickness of 80 ft (Catacosinos ductivities (0.2 to 0.5 ft/day) (Westjohn and Weaver, 1996b). and others, 2001). In the southern portion of Emmet County, bedrock wells are located where the Traverse Group forms the bedrock surface. Emmet County Bedrock wells occur in the northern portion of the county, where the remaining Devonian strata form the bedrock Emmet County is located in the northern Lower Pen‑ surface. The Dundee Limestone underlies the Traverse Group. insula. The Boardman‑Charlevoix, Lake Michigan, Lone Gardener (1974) divided the Dundee Limestone into the Roger Lake‑Ocqueoc, Cheboygan, and Lake Huron watersheds City Member and underlying Reed City Member. The Rog‑ are included in the county. According to the February 2005 ers City Member is composed of dolomitized limestone in the Wellogic database, approximately 75 percent of the wells in western portion of the State and impermeable limestone in the Emmet County are completed in the glacial deposits, and 11 eastern portion of the State. The Reed City member is com‑ percent in the bedrock units. There is insufficient informa‑ posed of porous dolomite underlain by anhydrite. The anhy‑ tion to make this distinction for 14 percent of the wells in the drite is absent in the eastern portion of the State (Gardener, county. The bedrock wells primarily occur in the northernmost 1974). and southernmost portions of the county. The Detroit River Group underlies the Dundee Lime‑ With the available information, glacial lithologies cannot stone. In the subsurface, the Detroit River Group consists of be regionally correlated in the subsurface. This is likely due the Lucas Formation, Amherstburg Formation, and Sylvania to the lateral and vertical heterogeneity of glacial deposits that Sandstone. The Lucas Formation is primarily composed of resulted from a complex depositional history. In the Michigan interlayered carbonates and evaporates, with carbonate‑ce‑ Basin, the glacial aquifer consists of sand and gravel that is mented, fine‑ to medium‑grained, sandstone lenses found part of a thick sequence of Pleistocene glacial deposits (West‑ throughout the basal portion of the formation. The Lucas john and others, 1994). The majority of the glacial deposits in Formation is up to 1,050 ft in thickness in the Michigan Basin. Emmet County range from 201 to 800 ft thick. However, the In some areas, the water from this formation is brine and may thickness of the glacial deposits spans from 0 to greater than contain hydrogen sulfide. The Amherstburg Formation under‑ 1,000 ft in the county, generally thinning to the north (Western lies the Lucas Formation. The Amherstburg Formation is up Michigan University, 1981). The glacial deposits in Emmet to 300 ft thick and is composed of fossiliferous limestone that County include outwash, till, and lacustrine deposits. The is dolomitized in some areas. An upper sandstone is present in outwash deposits are composed of sand and gravel. The till is the formation in the western portion of the basin. The Sylvania primarily coarse‑grained material. Lacustrine deposits in the Sandstone underlies the Amherstburg Formation. The Sylvania county are typically composed of sand and gravel. In addition, Sandstone is composed of fine‑ to medium‑grained sandstone dune sand can be found along the shoreline of Lake Michigan. with quartz overgrowths interlayered with carbonate. (Gardner, Also, peat and muck deposits occur in the central and north‑ 1974). western portion of the county (Farrand and Bell, 1982). The Bois Blanc Formation underlies the Grand River Bedrock underlies the glacial deposits in the county. The Group in Emmet County. The Bois Blanc Formation is bedrock surface is composed of rocks of Devonian age, from predominately composed of carbonates, including limestone south to north, these are the Antrim Shale, Traverse Group, (which may be fossiliferous in some areas), dolomite with Dundee Limestone, Detroit River Group and Bois Blanc For‑ chert, and dolomitic limestone. The basal unit of the Bois County Summaries 

Blanc formation is composed of a clastic or conglomerate Saginaw aquifer may yield hard water that is high in chloride layer (Gardener, 1974). and iron. Although hardness and iron content is often lower in the Saginaw aquifer than the glacial aquifer, the chloride content is often much higher (Wiitala and others, 1963). In Genesee County Genesee County, the Saginaw aquifer yields both fresh and saline water (Westjohn and Weaver, 1996c). Transmissiv‑ Genesee County is in the eastern south‑central portion ity for the Saginaw aquifer in Genesee County ranges from of the Lower Peninsula. The western half of Genesee County 200 to 1,800 ft2/day (Wiitala and others, 1963). The Saginaw is located in the Saginaw Lowlands (Westjohn and Weaver, confining unit underlies the Saginaw aquifer. The Saginaw 1998). The Shiawassee, Flint, and Cass watersheds drain the confining unit is approximately 50 ft thick in the county. It is county. According to the February 2005 Wellogic database, primarily shale, with thin layers of discontinuous sandstone, approximately 23 percent of the wells in Genesee County siltstone, limestone, and coal. The permeable layers within the are completed in the glacial deposits, and 73 percent in the Saginaw confining unit appear to be isolated from the regional bedrock units. There is insufficient information to make this ground‑water‑flow system (Westjohn and Weaver, 1996a). distinction for 4 percent of the wells in the county. The Saginaw confining unit separates the Saginaw aqui‑ In the Michigan Basin, glacial aquifers consist of sand fer from the underlying Parma‑Bayport aquifer. The Parma and gravel that are part of a thick sequence of Pleistocene Sandstone is often considered the basal unit of the Saginaw glacial deposits. With the available information, glacial Formation, although the stratigraphic relationship is not lithologies cannot be regionally correlated in the subsurface. clear between the Saginaw Formation, Parma Sandstone, and This is likely due to the lateral and vertical heterogeneity of Mississippian‑aged Bayport Limestone. The Parma Sandstone glacial deposits that resulted from a complex depositional is composed of medium‑ to coarse‑grained sandstone, and is history (Westjohn and others, 1994). Glacial deposits in generally less than 100 ft thick (Cohee and others, 1951). The Genesee County are primarily composed of materials with low Bayport Limestone is a fossiliferous, cherty limestone, often permeability, primarily clay, silt, with some fine sand. Both with interbedded sandstone and varies considerably in thick‑ the surficial and underground sand and gravel deposits vary ness from one area to another. The Bayport Limestone and in permeability both laterally and horizontally. Some of the Parma Sandstone appear to interfinger throughout the Michi‑ sand and gravel deposits have been cemented with calcium gan Basin (Westjohn and Weaver, 1996a). Bayport Limestone carbonate, reducing permeability (Wiitala and others, 1963). is eroded completely in some areas in the county (Wiitala and Glacial deposits include till, outwash, and lacustrine deposits others, 1963). These units are hydraulically connected, and in Genesee County. The till in the county is fine to medium together they form the Parma‑Bayport aquifer (Westjohn and grained (Farrand and Bell, 1982). Till is present in moraines Weaver, 1996a). The Parma‑Bayport aquifer is approximately and till plains. Moraines are present across the county, trend‑ 100 to 150 ft thick within the Michigan Basin. Please note that ing northeast to southwest. Till plains occur in the southern due to the uncertainty of stratigraphic relationship between portion of the county. Glacial outwash occurs along the Shia‑ these units, in other reports this aquifer may be delineated dif‑ wassee and Flint Rivers. In the northern portion of the county, ferently. The Parma‑Bayport aquifer may contain saline water lacustrine deposits and beach deposits dominate the landscape. in Genessee County (Westjohn and Weaver, 1996c). The permeability of glacial deposits varies in Genesee County. Bayport Limestone and the underlying Michigan For‑ However, localized, sand and gravel lenses are present that are mation subcrop, generally, between the Saginaw Formation highly permeable. In Genesee County, the transmissivity val‑ and the Marshall Sandstone. In Genesee County, the Bayport ues for the glacial aquifer range between 300 to 9,350 ft2/day. Limestone and Michigan Formation have a combined maxi‑ Water from the glacial aquifer may be hard and/or contain mum thickness of 210 ft. The Michigan Formation is com‑ high levels of iron and chloride. In the county, hydrogen sul‑ posed of sandstone, shale, limestone, and occasional dolo‑ fide has been found in water from the glacial aquifer (Wiitala mite. Gypsum and anhydrite are also present in the Michigan and others, 1963). Formation. The lower permeability lithologies of the Michigan Bedrock underlies the glacial deposits. The Saginaw Formation are usually considered a confining unit (Westjohn Formation, Michigan Formation, and Marshall Sandstone form and Weaver, 1996b). Some water, however, may be obtained the primary bedrock aquifers in Genesee County. The Saginaw locally from solution cavities from limestone or from sand‑ Formation is thinnest at the contact with the Michigan Forma‑ stone units, where the Michigan Formation forms the bedrock tion and thickest in northwest Genesee County (up to 323 ft). surface (Wiitala and others, 1963). The Saginaw Formation consists of discontinuous layers of The Marshall Sandstone underlies the Michigan For‑ sandstone, sandy shale, shale, coal, and limestone. The water mation, and subcrops in areas along the eastern edge of the obtained from the Saginaw Formation arises mainly from the county, and near the southern part of the county. In Genesee sandstone beds that form the Saginaw aquifer (Wiitala and County, the Marshall Sandstone is thickest in the northern others, 1963; Westjohn and Weaver, 1996a). The Saginaw portion and ranges in thickness from less than 70 to 200 ft. In aquifer often supplies moderate to large supplies of water; general, the Marshall Sandstone consists of sandstone with however, the quality of the water may be a problem. The some interbeds of shale, conglomerate, and dolomite (Wiitala  Summary of Hydrogeologic Conditions by County for the State of Michigan and others, 1963). The Marshall Sandstone is often divided (Western Michigan University, 1981). The glacial deposits are into two units the upper and lower Marshall sandstone. The composed of lacustrine deposits, till, and outwash. Lacustrine upper is composed of quartzarenite to sublitharenite that is deposits are present in the eastern and southern portion of the referred to as the Napoleon Sandstone Member. A shale, county. Both sand‑and‑gravel dominated and clay‑and‑silt siltstone, and/or carbonate layer separate the Napoleon Sand‑ dominated lacustrine deposits are present in the county. Till is stone Member from the lower Marshall sandstone. The lower present in moraines and till plains. Fine‑ to coarse‑grained till Marshall sandstone can be further divided into two units: an is present primarily in the northwestern corner of the county, upper, fine‑ to medium‑grained quartzarenite to sublitharenite but also occurs in areas of the eastern side of the county. and a basal fine‑ to medium‑grained litharenite. The continu‑ Outwash is present along the northwestern edge of the county ous sandstones in the Marshall Sandstone are considered the (Farrand and Bell, 1982). Outwash is highly permeable and is Marshall aquifer (Westjohn and Weaver, 1996b). In Genesee composed of sand and gravel. According to the Public Water County, the Napoleon Sandstone Member may comprise most Supply database, the estimated transmissivities from aqui‑ of the Marshall Sandstone. However near Grand Blanc Town‑ fer tests for the glacial wells in Gladwin County range from ship and the southern portion of Flint Township, there is an approximately 4,630 to 5,120 ft2/day. abundance of dolomite and shale where the Marshall Sand‑ Bedrock underlies the glacial deposits. According to the stone is present. The majority of the wells that tap the Mar‑ Public Water Supply database, the estimated transmissivities shall Sandstone are located in the eastern and southern parts from aquifer tests for a bedrock well in Gladwin County is of Genesee County. The Marshall aquifer yields moderate to approximately 2,730 ft2/day. The bedrock surface of Gladwin large supplies of water in areas of the county. Saline water is County is composed of the Jurassic “red beds” and the Sagi‑ common where the Marshall Sandstone is overlain by younger naw Formation (Milstein, 1987). The Jurassic “red beds” are bedrock. However, where the Marshall Sandstone forms the generally 50 to 150 ft thick (Westjohn and others, 1994). “Red bedrock surface, the water is generally fresh (Wiitala and oth‑ beds” occur primarily in the southern portion of the county ers, 1963). (Milstein, 1987). The “red beds” consist of red clay, mudstone, siltstone, and sandstone, and also include gray‑green shale, gypsum, and mudstone (Shaffer, 1969). The “red beds” are Gladwin County considered to be a confining unit in Michigan (Westjohn and others, 1994). Gladwin County is in the north‑central portion of the The Saginaw Formation underlies the Jurassic deposits, Lower Peninsula of Michigan. The eastern portion of the when “red beds” are present. Interbedded sandstone, siltstone, county is in the Saginaw Lowlands (Westjohn and Weaver, shale, coal, and limestone compose the Saginaw Formation. 1998). The Kawkawlin‑Pine and Tittabawassee watersheds The Saginaw aquifer is the hydraulically connected sandstones drain the county. According to the February 2005 Wellogic in the Saginaw Formation (Westjohn and Weaver, 1998). database, approximately 75 percent of the wells in Gladwin Within the State, the Saginaw aquifer ranges from less than County are completed in the glacial deposits, and 13 percent 100 to 370 ft thick. The Saginaw aquifer yields fresh water in in the bedrock units. There is insufficient information to make Gladwin County (Westjohn and Weaver, 1996c). The Saginaw this distinction for 12 percent of the wells in the county. The confining unit underlies the Saginaw aquifer, and ranges in western side of the county contains primarily glacial wells, thickness from less than 100 to 240 ft within the State. The while the eastern portion of the county, in the Saginaw Low‑ Saginaw confining unit is mostly shale, with thin layers of lands, contains both glacial and bedrock wells. discontinuous sandstone, siltstone, limestone, and coal. The Dune sand is present on the edge of the eastside of the permeable layers within the Saginaw confining unit appear to county. In the western and northern portions of the county, be isolated from the regional ground‑water‑flow system (West‑ the soils are fairly well drained and are medium textured. The john and Weaver, 1996a). northern border of the county has sandy hills, and sand is pres‑ The Saginaw confining unit separates the Saginaw aqui‑ ent in Gladwin County, east of the . The fer from the underlying Parma‑Bayport aquifer. The Parma remainder of the county is covered in wet, sandy soils that are Sandstone is often considered the basal unit of the Saginaw underlain by clay (Michigan Water Resources Commission, Formation, although the stratigraphic relationship is not 1960). clear between the Saginaw Formation, Parma Sandstone, and In the Michigan Basin, glacial aquifers consist of sand Mississippian‑aged Bayport Limestone. The Parma Sandstone and gravel that are part of a thick sequence of Pleistocene gla‑ is composed of medium‑ to coarse‑grained sandstone, and cial deposits. With the available information, glacial litholo‑ is generally less than 100 ft thick (Cohee and others, 1951). gies cannot be regionally correlated in the subsurface. This is The Bayport Limestone is a fossiliferous, cherty limestone, likely due to the lateral and vertical heterogeneity of glacial often with interbedded sandstone and varies considerably in deposits that resulted from a complex depositional history thickness from one area to another. The Bayport Limestone (Westjohn and others, 1994). In Gladwin County, the thick‑ and Parma Sandstone appear to interfinger throughout the ness of the glacial deposits ranges from approximately 100 Michigan Basin. These units are hydraulically connected, and to 600 ft. The thickness generally increases to the northwest together they form the Parma‑Bayport aquifer (Westjohn and County Summaries 

Weaver, 1996a). The Parma‑Bayport aquifer is approximately along with some clay (Barton and Grannemann, 1998). There 100 to 150 ft thick within the Michigan Basin. Please note that is not much information available concerning the amount due to the uncertainty of stratigraphic relationship between of water the swamp deposits may supply. However, where these units, in other reports this aquifer may be delineated coarse‑grained glacial outwash underlies the postglacial differently. The Parma‑Bayport aquifer yields saline water or deposits, ground water yields are high (Doonan and Hendrick‑ brine in Gladwin County (Westjohn and Weaver, 1996c). son, 1968). The Michigan Formation underlies the Bayport Lime‑ Aquifers in the glacial deposits consist largely of sands stone. The Michigan Formation consists of layers of sand‑ and gravels and vary regionally in thickness and permeability. stone, siltstone, anhydrite or gypsum, dolomite, limestone, Glacial deposits are heterogeneous in the subsurface. Glacial and shale. The lower permeability lithologies of the Michigan deposits in the county are composed of outwash, moraines, Formation are considered a confining unit that separates the till‑plain, and lacustrine deposits. Outwash is primarily com‑ Parma‑Bayport aquifer from the underlying Marshall aquifer. posed of sand and gravel with lenses of silt and clay. Outwash The thickness of the Michigan confining unit ranges from is most abundant in the southeastern and south‑central portion less than 50 to 400 ft within the State (Westjohn and Weaver, of the county. Large yields of ground water may be obtained 1998). from these deposits. Moraines dominate the eastern portion of The Marshall Sandstone underlies the Michigan Forma‑ the county, and occur sporadically throughout the rest of the tion. The Marshall Sandstone is composed of an upper quartz‑ county. In the south‑central and southwestern portions of the arenite to sublitharenite that is referred to as the Napoleon county, small to moderate yields of ground water are obtained Sandstone Member. A shale, siltstone, and/or carbonate layer from moraines. In other areas of the county, moraines may separates the Napoleon Sandstone Member from the lower supply small to large amounts of water. Till plains, composed Marshall sandstone. The lower Marshall sandstone is com‑ of a combination of boulders, gravel, sand, silt, and clay, prised of two units. The upper unit is generally 50 to 125 ft of dominate the west‑central portion of the county, and also occur fine‑ to medium‑grained quartzarenite to sublitharenite. At the throughout other areas of the county. In the west‑central por‑ base of the Marshall Sandstone is a fine‑ to medium‑grained tion of the county, sand and gravel dominates these deposits litharenite that ranges in thickness from 30 to 125 ft. Perme‑ and moderate to large yields of ground water are obtained. able sandstones in the Marshall Sandstone comprise the Mar‑ Small to moderate ground‑water yields are acquired from shall aquifer. The Marshall aquifer ranges in thickness from 75 till‑plain deposits in the rest of the county. Lacustrine deposits to greater than 200 ft within the State (Westjohn and Weaver, in this area are composed of silt and clay with lenses of fine 1998). The Marshall Sandstone yields saline water or brine in sand and generally yield small amounts of ground water. In Gladwin County (Westjohn and Weaver, 1996c). general, the ground water in the county may be moderately Coldwater Shale underlies the Marshall Sandstone. hard and contain iron. A few deep glacial wells in the county Coldwater Shale consists of primarily shale with interbeds or have tapped saline water. In Gogebic County the estimated lenses of sandstone, siltstone, and dolomite. Coldwater Shale transmissivity for glacial wells was calculated from the spe‑ is relatively impermeable and is considered a confining unit in cific capacity data of Doonan and Hendrickson (1968) and most of Michigan (Westjohn and Weaver, 1998). range from 63 to 20,174 ft2/day. According to the Public Water Supply database, the estimated transmissivity for glacial wells ranges from approximately 1,440 to 17,280 ft2/day. Gogebic County The Lac Vieux Desert Indian Community and vicin‑ ity is located in the southeastern portion of Gogebic County Gogebic County is along the western edge of the Upper and extends into Vilas County, Wisconsin. This area is in the Peninsula of Michigan. Gogebic County mainly drains into Upper Wisconsin watershed, and Lac Vieux Desert, a 6.6 mi2 Lake Superior via the Black, Montreal, Presque Isle, or lake and its tributaries, are the headwaters of the Wisconsin Ontonagon Rivers. In the southeastern portion of the county a River. Glacial deposits are up to 200 ft thick in this area. small area drains into Lake Michigan. Ground‑water resources Drumlins are present in the southern and eastern borders of may be difficult to obtain and are not uniformly distributed in Lac Vieux Desert. The drumlins are composed of glacial this area (Doonan and Hendrickson, 1968). According to the deposits that are silty and clay rich, and till that is gravel and February 2005 Wellogic database, approximately 55 percent sand rich. In the Lac Vieux Desert area, the aquifer system is of the wells in Gogebic County are completed in the glacial generally layered consisting of an unconfined aquifer under‑ deposits, and 41 percent in the bedrock units. There is insuf‑ lain by a confined aquifer or series of confined aquifers. In ficient information to make this distinction for 4 percent of the some areas only a confined aquifer may be present. The aqui‑ wells in the county. fer material is composed of sand and gravel and some clay. Postglacial deposits consist of swamp deposits and The aquifer material is generally 5 to less than 100 ft thick. A recent alluvium. These deposits are composed of muck, peat, discontinuous gravel aquifer occurs in this area, approximately sand, silt, and clay (Doonan and Hendrickson, 1968). In 96 to 188 ft below ground, and has been recorded from 3 to 15 the southeastern area of the county, in the Lac Vieux Desert ft thick in well logs. This gravel aquifer is capable of yields up area, swamp deposits are often underlain by sand and gravel to 30 gal/min. The confined aquifer tends to yield more water  Summary of Hydrogeologic Conditions by County for the State of Michigan than the unconfined aquifer in this region. Confining layers are present on the surface in the majority of the county (Cum‑ 10 to 100 ft thick composed of till and debris‑flow deposits mings and others, 1990). The Mancelona Outwash Plain that are rich in clay. The water originating from the glacial separates the two portions of the Port Huron Moraine (Leverett aquifer is moderately hard and alkaline, and has low iron con‑ and Taylor, 1915). Till deposits are made up of a wide array centrations (Barton and Grannemann, 1998). of materials including clay, silt, sand, gravel, and, occasion‑ The Bessemer area is located in the western Goge‑ ally, boulders. These deposits are found in moraines and till bic County. In this area, much of the glacial aquifer is also plains. Leverett and Taylor (1915) identified the northeast‑ considered confined or semi‑confined. This is due to a layer ern moraine as the Inner Port Huron Moraine. The southern of impermeable till that covers most of this region. Transmis‑ moraine is termed the Outer Port Huron Moraine (Leveret sivity values in the glacial aquifer in the Bessemer area have and Taylor, 1915). The Manistee Moraine is also present in been calculated from specific capacity data and range between the northwestern portion of the county. Blewett and Winters 2,502 and 9,240 ft2/day (Brown and Stuart, 1951). (1995) determined that the surficial deposits of the Port Huron Bedrock dips to the north, and consists of Precambrian Moraine were primarily composed of glaciofluvial sand and metamorphosed and igneous rocks overlying older igneous gravel. Thin layers of till separated by sand and silt may occur and metamorphic rocks (Brown and Stuart, 1951). These in the subsurface of the moraine. The base of the Port Huron rocks are relatively impermeable. Therefore, Barton and Moraine is composed of thick clay and gravel (Boutt, 1999). Grannemann (1998) consider the bedrock surface be the base Till plains contain drumlins and are found in the northeastern of the aquifer in southeastern portion of the county. How‑ portion of the county and on Old Mission Peninsula. Lacus‑ ever, in the western and central areas of the county, bedrock trine deposits are present in the north‑central portion of the outcrops or maybe covered by only a thin layer of glacial county and on Old Mission Peninsula. The lacustrine deposits deposits. Small water yields may be obtained from bedrock are composed of sand, gravel, and clay, dependent upon the wells due to fracturing of the rock. Specific capacity data was location (Twenter and others, 1985; Cummings and others, available for one bedrock well in Gogebic County and used to 1990). Twenter and others (1985) studied the lacustrine depos‑ calculate a transmissivity value of 4,065 ft2/day (Doonan and its in East Bay Township and the U.S. Coast Guard Air Station Hendrickson, 1968). According to the Public Water Supply in greater detail. In this area, the lacustrine glacial deposits are database, the estimated transmissivity for a bedrock well in the composed of two units: a permeable sand and gravel unit and county is approximately 2,320 ft2/day. an underlying, relatively impermeable, clay unit. The sand and gravel unit has a total thickness from 29 to 188 ft. This unit is composed of 15 to 20 ft of fine‑ to medium‑grained sand, Grand Traverse County and below this depth coarser‑grained sand and gravel is more abundant. The underlying clay unit is estimated to be from 100 Grand Traverse County is in the northwestern portion of to 200 ft thick. The clay unit dips to the east at 45 ft/mile or the Lower Peninsula of Michigan. The Manistee, Betsie‑Platte, the southeast at 500 ft/mile (Twenter and others, 1985). Boardman‑Charlevoix, and Lake Michigan watersheds drain In the Michigan Basin, glacial aquifers consist of sand the county. On the north, Grand Traverse County is bounded and gravel that are part of a thick sequence of Pleistocene by the East and West arms of the Grand Traverse Bay. In glacial deposits (Westjohn and others, 1994). Layers of till and the northwestern part of the county, near Bass Lake, a major clay form confining units and are found throughout the Grand groundwater divide extends north to south for about 10 mi Traverse County on the surface and in the subsurface. Lower and then continues eastward toward Fife Lake, in the south‑ units in the glacial deposits are confined or semi‑confined by eastern periphery of the county. Ground water flows into the these layers. Unconfined conditions exist where outwash and Boardman River or Grand Traverse Bay, north and east of the coarse‑grained lacustrine deposits are present at the surface divide. South and east of the divide, ground water flows into and wells are often shallow, less than 100 ft in depth, in these neighboring counties (Cummings and others, 1990). Accord‑ areas (Cummings and others, 1990). Based on aquifer tests ing to the February 2005 Wellogic database, approximately 97 from the area, the estimated transmissivity and hydraulic percent of the wells in Grand Traverse County are completed conductivity for the glacial aquifer range from 1,800 to 2,500 in the glacial deposits, and 0 percent in the bedrock units. ft2/day and 50 to 150 ft/day, respectively (Twenter and others, There is insufficient information to make this distinction for 3 1985; Cummings and others, 1990). According to the Public percent of the wells in the county. Water Supply database, the estimated transmissivity for glacial With the available information, glacial lithologies cannot wells ranges from approximately 1,260 to 5,120 ft2/day. Bed‑ be regionally correlated in the subsurface. This is likely due rock underlies the glacial deposits, but is not currently used for to the lateral and vertical heterogeneity of glacial deposits water supply. that resulted from a complex depositional history (Westjohn Ground‑water quality is of interest in all Michigan coun‑ and others, 1994). Glacial deposits in Grand Traverse County ties. In Grand Traverse County, nitrate concentrations in 1.6 range from 0 to 900 ft in thickness and are made up of an percent of the ground water sampled equaled or exceeded the assemblage of outwash, till, and lacustrine deposits. The U.S. EPA maximum contaminant level of 10 ppm. The mean outwash deposits, which are composed of sand and gravel, are concentration of nitrate in ground water in Grand Traverse County Summaries 

County is below U.S. EPA drinking water regulations (Cum‑ locally contain high sulfate concentrations (Vanlier, 1963b). mings and others, 1990). Organic chemicals are present in the In the Alma area, till contains large amounts of clay and is not ground water in some areas of the county (Twenter and others, very permeable (Vanlier, 1963b). A well completed in glacial 1985). till or outwash, located in Elwell, had a hydraulic conductiv‑ ity ranging from 8.6 x 10‑3 to 86.4 ft/day (Rogers and others, 1996). Gratiot County The bedrock underlies the glacial deposits. The bedrock surface of the county consists of “red beds”, the Grand River Gratiot County is in the central part of the Lower Pen‑ Formation, and the Saginaw Formation. In some areas of Gra‑ insula of Michigan. The Maple, Pine, Tittabawassee, and tiot County, Jurassic‑aged “red beds” are present beneath the Shiawassee watersheds drain the county in the southern, north glacial deposits, and consist of clay, mudstone, siltstone, and central and northwest, northeast, and eastern portions of the sandstone containing discontinuous beds of gypsum, and shaly county, respectively. The Tittabawassee watershed includes the sandstones. “Red beds” are considered to be a confining unit northern portion of Gratiot County and contains soils that are based on geophysical data (Westjohn and Weaver, 1998). intermediately drained and medium to heavy‑textured (Michi‑ The Grand River Formation is generally 50 to 100 gan Water Resources Commission, 1960). According to the ft thick and is small in aerial extent within the State. It is February 2005 Wellogic database, approximately 85 percent primarily composed of coarse‑grained sandstone with layers of the wells in Gratiot County are completed in the glacial of shale, carbonate, and coal (Catacosinos and others, 2001). deposits, and 12 percent in the bedrock units. There is insuf‑ The Grand River Formation is difficult to differentiate from ficient information to make this distinction for 3 percent of the the underlying Saginaw Formation. The Saginaw Formation wells in the county. contains interbeds of sandstone, siltstone, limestone, coal, and With the available information, glacial lithologies cannot shale (Westjohn and Weaver, 1996a). The Saginaw Formation be regionally correlated in the subsurface. This is likely due consists of shale, coal, sandy shale, sandstone, limestone, and to the lateral and vertical heterogeneity of glacial deposits that sandstone. In the Alma area, the Saginaw Formation is 200 to resulted from a complex depositional history (Westjohn and 350 ft thick and yields moderate supplies of water (Vanlier, others, 1994). In the county, the thickness of the glacial depos‑ 1963b). The Parma Sandstone is often considered the basal its ranges from 51 to 600 ft (Western Michigan university, unit of the Saginaw Formation, although the stratigraphic 1981). Glacial deposits in Gratiot County include lacustrine relationship is not clear between the Saginaw Formation, deposits, outwash, and till (Farrand and Bell, 1982; Vanlier, Parma Sandstone, and underlying Mississippian‑aged Bayport 1963b). In general, lacustrine sand and gravel deposits domi‑ Limestone. The Parma Sandstone is composed of medium‑ to nate the southeastern portion of the county; while deposits in coarse‑grained sandstone, and is generally less than 100 ft the central portion of the county are primarily lacustrine clay thick (Cohee and others, 1951). and silt. Outwash is composed of sand and gravel. In the Alma The Pennsylvanian bedrock above the Parma Sandstone area, lenses of silt and clay are present in the outwash, and can be divided into an upper sandstone aquifer and a lower outwash deposits are capable of supplying moderate to large confining unit. The Saginaw aquifer is in the sandstones amounts of water to wells. Till may consist of clay, silt, sand, from the Grand River and Saginaw Formations. The Saginaw gravel, and boulders. In Gratiot County, fine to coarse‑grained aquifer ranges in thickness from less than 100 to 370 ft within till is present (Farrand and Bell, 1982). the State (Westjohn and Weaver, 1996a). In Gratiot County, in Aquifers in the glacial deposits consist largely of sands an area where the Saginaw aquifer is 75 ft thick, based on an and gravels and vary regionally in thickness and permeability. aquifer test, and the transmissivity and storage coefficient were According to the Public Water Supply database, the estimated estimated to be 320 ft2/day and 1.2 x 10‑4, respectively. Water transmissivity for glacial wells in Gratiot County ranges from from the Saginaw aquifer contains objectionable amounts approximately 1,270 to 5,050 ft2/day. In the Alma area, shal‑ of chloride in areas of Gratiot County (Vanlier, 1963b). The low (0 to 30 ft in depth) lacustrine deposits are composed of Saginaw aquifer yields both saline and fresh water in Gratiot sand and silt and may yield small supplies of water. The water County (Westjohn and Weaver, 1996c). The Saginaw confin‑ from the shallow lacustrine deposits is generally hard and high ing unit underlies the Saginaw aquifer. The Saginaw confining in iron, and locally high in nitrate. Deeper lacustrine deposits unit is approximately 50 to 100 ft thick within the county, and in the Alma area also include sandy and silty clay deposits that is mostly shale, with thin layers of discontinuous sandstone, act as a partially confining layer. These deposits do not supply siltstone, limestone, and coal. The permeable layers within the water. The western portion of the Alma area is underlain with Saginaw confining unit appear to be isolated from the regional buried outwash, and this is the main source of water for the ground‑water‑flow system (Westjohn and Weaver, 1996a). city. Transmissivity values were estimated from the coefficient The Saginaw confining unit separates the Saginaw aqui‑ of transmissibility for wells in buried‑outwash deposits using fer from the underlying Parma‑Bayport aquifer. The Parma flow‑net analysis and pumping tests. These values range from Sandstone is often considered the basal unit of the Saginaw 1,537 to 2,673 ft2/day and 1,604 to 4,411 ft2/day, respectively. Formation, although the stratigraphic relationship is not Water from the buried‑outwash deposits may be very hard and clear between the Saginaw Formation, Parma Sandstone, and  Summary of Hydrogeologic Conditions by County for the State of Michigan

Mississippian‑aged Bayport Limestone. The Parma Sandstone 33 percent in the bedrock units. There is insufficient informa‑ is composed of medium‑ to coarse‑grained sandstone, and tion to make this distinction for 4 percent of the wells in the is generally less than 100 ft thick (Cohee and others, 1951). county. The Bayport Limestone is a fossiliferous, cherty limestone, Aquifers in the glacial deposits consist largely of sands often with interbedded sandstone and varies considerably and gravels and vary regionally in thickness and permeability. in thickness from one area to another. The Bayport Lime‑ With the available information, glacial lithologies cannot be stone and Parma Sandstone appear to interfinger throughout regionally correlated in the subsurface. This is likely due to the Michigan Basin (Westjohn and Weaver, 1996a). These the lateral and vertical heterogeneity of glacial deposits that units are hydraulically connected, and together they form resulted from a complex depositional history (Westjohn and the Parma‑Bayport aquifer. The Parma‑Bayport aquifer is others, 1994). The glacial deposits in Hillsdale County consist approximately 100 to 150 ft thick within the Michigan Basin of outwash, moraines, and till plains. Outwash is generally (Westjohn and Weaver, 1996a). Please note that due to the concentrated in the northwestern half of the county (Farrand uncertainty of stratigraphic relationship between these units, and Bell, 1982). Outwash deposits consist of sand and gravel in other reports this aquifer may be delineated differently. In that is highly permeable. A glaciofluvial well, located in Gratiot County, water from this aquifer may be saline or brine Jonesville had a hydraulic conductivity ranging from approxi‑ (Westjohn and Weaver, 1996c). mately 2.9 to 285 ft/day (Rogers and others, 1996). Moraines The Michigan Formation underlies the Bayport Lime‑ and till plains are composed of till. Till is a mixture of clay, stone. The Michigan Formation is composed of sandstone, silt, sand, gravel, and boulders. In Hillsdale County, till is pri‑ shale, limestone, and occasional dolomite. Gypsum and anhy‑ marily medium to coarse grained. Till deposits occur through‑ drite are also present in the formation. The lower permeability out the county, but are dominant in the southeastern half of lithologies of the Michigan Formation are considered to be a the county (Farrand and Bell, 1982). According to the Public confining unit that separates the Parma‑Bayport aquifer from Water Supply database, the estimated transmissivity for glacial the underlying Marshall aquifer. The Michigan confining unit wells in Hillsdale County ranges from approximately 6,685 to is ranges from less than 50 to greater than 400 ft thick in the 38,760 ft2/day. State (Westjohn and Weaver, 1996b). Bedrock underlies the glacial deposits. The Marshall The Marshall Sandstone underlies the Michigan For‑ Sandstone and underlying Coldwater Shale form the bedrock mation. The Marshall Sandstone consists of one or more surface of Hillsdale County. In general, the Marshall Sand‑ stratigraphically continuous permeable sandstones. The upper stone is a micaceous sandstone. In other areas of the State, the sandstone is a quartzarenite to sublitharenite that is referred to Marshall Sandstone has been described in more detail. The as the Napoleon Sandstone Member. A shale, siltstone, and/or Marshall Sandstone consists of one or more stratigraphically carbonate layer separates the Napoleon Sandstone Member continuous permeable sandstones. The upper sandstone is a from the underlying lower Marshall sandstone. The lower quartzarenite to sublitharenite that is referred to as the Napo‑ Marshall sandstone is comprised of two units. The upper unit leon Sandstone Member. A shale, siltstone, and/or carbonate is generally 50 to 125 ft of fine‑ to medium‑grained quartzare‑ layer separates the Napoleon Sandstone Member from the nite to sublitharenite. At the base of the Marshall Sandstone is underlying lower Marshall sandstone. The lower Marshall a fine‑ to medium‑grained litharenite that ranges in thickness sandstone is comprised of two units. The upper unit is gener‑ from 30 to 125 ft. Permeable sandstones in the Marshall Sand‑ ally 50 to 125 ft of fine‑ to medium‑grained quartzarenite to stone comprise the Marshall aquifer. The Marshall aquifer sublitharenite. At the base of the Marshall Sandstone is a fine‑ ranges in thickness from 75 to greater than 200 ft within the to medium‑grained litharenite that ranges in thickness from State (Westjohn and Weaver, 1998). The Marshall Sandstone 30 to 125 ft. Permeable sandstones in the Marshall Sandstone yields brine in Gratiot County (Westjohn and Weaver, 1996c). comprise the Marshall aquifer. The Marshall aquifer ranges Underlying the Marshall Sandstone is the Coldwater in thickness from 75 to greater than 200 ft within the State Shale. The Coldwater Shale consists of shale, sandstone, (Westjohn and Weaver, 1998). According to the Public Water siltstone, and carbonates. It is considered a confining unit and Supply database, based on aquifer tests, the estimated trans‑ ranges in thickness from 500 to 1,300 ft west to east across the missivity for a well in the Marshall aquifer is approximately State. (Westjohn and Weaver, 1996b). 7,340 ft2/day. The Marshall Sandstone supplies freshwater in Hillsdale County (Westjohn and Weaver, 1996c). Coldwater Shale underlies the Michigan Formation and Hillsdale County is composed of shale, sandstone, siltstone, and carbonates. The sandstone and siltstone layers in this unit thin to the west Hillsdale County is in the southern portion of the Lower across the State, while carbonates become more abundant Peninsula of Michigan, and borders Indiana and . The (Monnett, 1948). Coldwater Shale is generally considered to St. Joseph, Kalamazoo, Upper Grand, Raisin, and Tiffin be a confining unit in areas of the State (Westjohn and Weaver, watersheds drain the county. According to the February 2005 1996b). Locally, however, in Hillsdale County the Coldwater Wellogic database, approximately 63 percent of the wells in Shale yields small water supplies. According to the Public Hillsdale County are completed in the glacial deposits, and Water Supply database, based on aquifer tests, the estimated County Summaries  transmissivity for a well in the Coldwater Shale is approxi‑ and the lacustrine clay deposits may act as local confining or mately 535 ft2/day. semi‑confining layers. Wells completed in lacustrine deposits provide only moderately hard water that may have high iron content (Doonan and others, 1970). Using the specific capacity Houghton County data from Doonan and others (1970), estimated transmissiv‑ ity values for the glacial aquifer range between 17 to 4,205 Houghton County is in the western Upper Peninsula of ft2/day. According to the Public Water Supply database, based Michigan. The Ontonagon, , Sturgeon, on aquifer tests the estimated transmissivity for glacial wells Dead‑Kelsey, and Lake Superior watersheds drain the county. ranges from approximately 140 to 100,800 ft2/day. The Sturgeon River drainage system and the East Branch of The bedrock aquifer underlies the glacial aquifer. Esti‑ the Ontonagon River drain most of Houghton County (Doonan mated transmissivity values range between 0.3 to 1,200 ft2/day and others, 1970). According to the February 2005 Wellogic for the bedrock aquifer. These values were calculated using database, approximately 34 percent of the wells in Houghton the specific capacity data of Doonan and others (1970). The County are completed in the glacial deposits, and 63 percent surface expression of the bedrock surface in Houghton County in the bedrock units. There is insufficient information to make trends northeast to southwest and the dip of the bedrock is this distinction for 3 percent of the wells in the county. Glacial toward the northwest. The Jacobsville Sandstone, composed of aquifers may be locally confined. In the northern portion of the sandstone, shale, and conglomerate layers, forms the bedrock county, the thickness of the glacial deposits is extremely vari‑ surface near the southeastern part of the county. Most of the able and igneous and metamorphic rocks are directly below water supply from bedrock aquifers in the county is obtained the glacial deposits. Where glacial deposits are thick, small to from Jacobsville Sandstone. Small to moderate yields of water moderate yields of water may be obtained. The igneous and are supplied from Jacobsville Sandstone wells. The quality of metamorphic rocks yield more water where these rocks are the ground water is generally acceptable. However, in deep highly fractured. In areas where the glacial deposits are greater wells, saline water may be tapped. The is than 50 ft thick and underlain by sedimentary bedrock, water exposed along the northwest portion of Houghton County and yields are high (Twenter, 1981). is arkosic sandstone interbedded with micaceous shale. Freda Post‑glacial deposits include stream and swamp depos‑ Sandstone is approximately 900 ft thick in Houghton County. its, such as, muck, peat, sand, and gravel. Wells from stream Underlying the Freda Sandstone is the , which deposits produce good quality water and enough water for is approximately 600 ft thick. The Copper Harbor Conglomer‑ domestic use. However, these wells may be tapping underlying ate is exposed at the bedrock surface in a thin strip slightly deposits, or shallow wells may be supplied by surface water inland from the Freda sandstone and is composed of boulder to also (Doonan and others, 1970). pebble‑sized clasts and arkose sandstone. The Copper Harbor Aquifers in the glacial deposits consist largely of sands Conglomerate includes two lava flows in northern Houghton and gravels and vary regionally in thickness and permeability. County. Water supplies from the Copper Harbor Conglom‑ Glacial deposits include till, outwash, and lacustrine deposits. erate are small to moderate, and the water may be saline in Ground moraines or till plains cover large areas of the county areas. The Portage Lake Lava Series underlies the Copper and range in thickness from 0 to 300 ft. In some areas, the till Harbor Conglomerate, consists of basaltic and andesitic lavas underlies outwash. Kames, kame terraces, eskers, and kettles interbedded with conglomerate, and is exposed at the bedrock are also present in the county, and composed of till that varies surface trending northeast to southwest and terminates at greatly in grain size. The Keweenaw Moraine occurs in central the . The southeastern portion of Houghton and southern Houghton County. The Keweenaw Moraine County contains an approximately 2 square mile area of the is composed of clay till and ranges in thickness from very South Range Traps, a Lower Keweenawan basaltic lava flow. thin to 360 ft thick. The sandy Marenisco Morainic Ridge No information is available on the water supply from these crosses the southern portion of the county. In moraines and rocks. The most southern portion of Houghton County is ground‑moraine wells, a layer of clay is usually penetrated composed of Middle Precambrian slate and greywacke of the before the deeper sand and gravel. These wells usually yield Animikie Series. Water supplies are small from the Animikie enough water for domestic use. Occasionally, the water may Series, and of good quality (Doonan and others, 1970). be high in iron. Outwash occurs in the southern part of the county and only as a thin deposit in the central portion of the county. These are predominantly sand and gravel. The Huron County southern outwash deposits are capable of yielding at least moderate supplies of good quality water. Lacustrine deposits Huron County in the Lower Peninsula on the eastern side are composed of layers of clay, sand, silt, and gravel. Lacus‑ of the State and is partially bound by Lake Huron and Saginaw trine deposits in the region are divided into clay rich units or Bay. The Pigeon‑Wiscoggin, Birch‑Willow, Cass, and Lake sand rich units. Most of the lacustrine deposits are sand and Huron watersheds are included in the county. The eastern supply more water than the clay deposits. Wells may also tap portion of the county is in Uplands and the western sand and gravel outwash deposits below the lacustrine deposits portion of the county is located in the Saginaw Lowlands. The 30 Summary of Hydrogeologic Conditions by County for the State of Michigan south central portion of the county is covered in rolling hills ever, small yields of water may be obtained from the lenses of and is part of the Port Huron moraine, while the remainder of sandstone, generally in the western and southwestern por‑ county is rather flat and slants toward Lake Huron and Sagi‑ tions of the county. These beds are usually confined by shale naw Bay. The general direction of ground‑water flow is from or silty shale. In Huron County, the water from the Saginaw southeast to northwest, towards Saginaw Bay (Sweat, 1992). Formation is usually hard and is generally only potable in the According to the February 2005 Wellogic database, approxi‑ Caseville area (Sweat, 1992). mately 6 percent of the wells in Huron County are completed The Bayport Limestone underlies the Saginaw Forma‑ in the glacial deposits, and 88 percent in the bedrock units. tion. The Bayport Limestone is a fossiliferous, cherty lime‑ There is insufficient information to make this distinction for stone, often with interbedded sandstone. The Bayport Lime‑ 6 percent of the wells in the county. Sand and gravel glacial stone forms the bedrock surface in areas in the western part of deposits, however, are not abundant or thick in the county, and the county. Locally, the Bayport Limestone may yield small the Marshall Sandstone is the principal aquifer (Sweat, 1992). amounts of good quality water. However, it is generally not Water quality may be an issue in areas of Huron County. considered an aquifer in the county (Sweat, 1992). Locally, the arsenic, cadmium, nitrate, and selenium concen‑ The Michigan Formation underlies the Bayport Lime‑ trations in ground water exceed USEPA maximum contami‑ stone. The Michigan Formation is composed of sandstone, nant levels (Sweat, 1992; Haack and Rachol, 2000c; Haack shale, limestone, and occasionally dolomite. Gypsum and and Trecanni, 2000). anhydrite are present throughout the Michigan Formation but In the Michigan Basin, glacial aquifers consist of sand are more abundant in the lower portion of the formation and and gravel that are part of a sequence of Pleistocene glacial in the western part of the state. Locally, wells in the Michigan deposits. With the available information, glacial lithologies Formation may supply water, generally in the western and cannot be regionally correlated in the subsurface. This is southwestern parts of the county. Often water from the forma‑ likely due to the lateral and vertical heterogeneity of glacial tion is saline. The Michigan Formation is generally considered deposits that resulted from a complex depositional history a confining unit and not an aquifer. In the western portion of (Westjohn and others, 1994). Glacial deposits range in thick‑ the county, water is high in dissolved sulfate probably due ness from less than 10 to 130 ft, and consist of till, outwash, to the high amount of gypsum in the Michigan Formation. and lacustrine deposits. Kames and drumlins are present in the (Sweat, 1992). south‑central portion of the county. Slightly south of the lacus‑ The Marshall Sandstone underlies the Michigan Forma‑ trine deposits, is a portion of the Port Huron Moraine that is tion. The uppermost sandstone unit is the Napoleon Sandstone composed of fine to coarse till with lenses of sand and gravel. Member, and is up to 120 ft thick. The Napoleon Sandstone Narrow portions of the morainal deposits, trending northeast Member is composed of medium to coarse sandstone, which to southwest, also occur on the eastern side of the county becomes finer near the base. Near the base, carbonaceous enclosed by the silt and clay lacustrine deposits. The sediment materials are present and layers of quartz pebbles occur all type of the morainal deposits may vary, however, clay‑rich through the formation. The Napoleon Sandstone yields large constitute the majority of morainal deposits. An area of glacial amounts of good quality water, and is considered the principal outwash and post‑glacial alluvium is present in the south‑cen‑ aquifer in Huron County. Underneath the Napoleon Sandstone, tral portion of the county. A well completed in glacial till or the lower portion of the Marshall Sandstone consists of three outwash, located in Bad Axe, had a hydraulic conductivity sandstone layers. The upper unit of sandstone is not distinct, ranging between 2.9 x 10‑2 to 285 ft/day (Rogers and others, however, it can be recognized as the layer bound by silty, 1996). Lacustrine deposits of silt and clay cover the county fine‑grained sandstone, with interbeds of shale. Below, the surface in an arc pattern from east to west in the northern por‑ middle lower sandstone is coarse grained. Beds of fine‑grained tion of the county. Sand and gravel lacustrine deposits occur sandstones and silty shales occur between the middle and along the shoreline, south of Wild Fowl Bay, in an area in the lowest sandstone. The lowest sandstone is well cemented and northwest part of the county, and in the south central portion composed of fine‑grained sandstone with lenses of pebbles of the county. A well completed in lacustrine deposits, located and silty sand. The depth of the Marshall Sandstone increases, in Kinde, had a hydraulic conductivity ranging between 2.9 x and the quality of water from the lower Marshall sandstone 10‑3 to 2.9 ft /day (Rogers and others, 1996). decreases in the southern and western ends of Huron County. Bedrock outcrops are present in Huron County, however However, potable water is obtained in some areas from the in general, bedrock underlies glacial deposits. The bedrock lower Marshall sandstone. Transmissivity for the Marshall surface in Huron County consists of the Saginaw Formation, Sandstone ranges from 7 to 1,300 ft2/day (Barton, 1995; Bayport Limestone, Michigan Formation, Marshall Sandstone, Sweat, 1992). The Marshall Sandstone is not as productive and Coldwater Shale. The Saginaw Formation forms the of an aquifer in Huron County as it is in other counties in bedrock surface in the western part of the county, and thick‑ the State. High chloride concentrations are found in wells ness of the formation is up to 100 ft. The Saginaw Forma‑ in southeastern Huron County from wells that tap the lower tion is primarily shale and silty shale with layers of siltstone, Marshall sandstone or the underlying Coldwater Shale (Sweat, fine‑grained sandstone, and coal. The Saginaw Formation is 1992). generally considered a confining unit in Huron County. How‑ County Summaries 1

The contact between the Marshall Sandstone and the glacier were covered by a layer of till deposited during a later Coldwater Shale is transitional. Lenses of slaty sandstone glacial advance. The most extensive area of buried outwash and conglomerate are present in the Coldwater Shale, which deposits are in the northern part of Ingham County. These is 1,000 to 1,200 ft thick in Huron County. Irregular beds of areas of buried outwash are a potential source of water to conglomerate occur in the upper portion of Coldwater Shale, wells; however, most wells in these areas are completed in near the contact with the overlying Marshall Sandstone. bedrock aquifers because of the better quality water available. Fine‑grained, silty sandstone with layers of shale and siltstone Till is present over much of the county and is generally not a comprise the upper portion of the Coldwater Shale where it source of water to wells. Locally the till may include thin beds outcrops in the eastern portion of Huron County. The Coldwa‑ of sand and gravel that are a source of water or may overlies ter Shale is generally considered a confining unit. However, bodies of sand and gravel that may yield moderate to large small yields of water are obtained from Coldwater Shale along supplies of water (Vanlier and others, 1973). the eastern shore of Huron County. The water from Coldwater The glacial deposits of Pleistocene age overlie Penn‑ Shale has a high dissolved solids concentration, and is gener‑ sylvanian [and Upper Jurassic] bedrock units in Ingham ally only suitable for stock. Large quantities of water with‑ County. Rocks of Triassic, [Lower and Middle] Jurassic, and drawn from certain localities could cause an upward migration Cretaceous age are missing (Mandle and Westjohn, 1989). of brine from the Coldwater Shale (Sweat, 1992). The Jurassic “red beds” which separate Pennsylvanian rocks from glacial deposits in some areas of the Lower Peninsula, are either entirely absent or only marginally present in the Ingham County Tri‑County region, which consists of Ingham, Clinton, and Eaton Counties (Westjohn and others, 1994). The “red beds” Ingham County is in the south‑central Lower Peninsula are often poorly consolidated or unconsolidated and consist of Michigan. The Upper Grand watershed covers the majority of primarily clay, mudstone, siltstone, sandstone, shale and of the county; a small area in southeastern Ingham County is gypsum. The “red beds” are relatively impermeable and are in the Huron watershed. According to the February 2005 Wel‑ considered a confining unit. The “red beds” impede the verti‑ logic database, approximately 3 percent of the wells in Ingham cal flow of water between glacial‑drift and bedrock aquifers County are completed in the glacial deposits, and 92 percent (Westjohn and others, 1994). in the bedrock units. There is insufficient information to make Discontinuous lenses of sandstone, shale, coal, and lime‑ this distinction for 5 percent of the wells in the county. Aqui‑ stone in the Pennsylvanian bedrock units have been formally fers in the glacial and bedrock units provide water in Ingham subdivided into two formations. The uppermost massive, County, but generally are not as highly productive in the north‑ coarse‑grained sandstones form the Grand River Formation; eastern part of the county (Vanlier and others, 1973). all remaining Pennsylvanian rocks are considered part of the The glacial deposits in Ingham County range in thick‑ underlying Saginaw Formation (Mandle and Westjohn, 1989). ness from less than 10 ft to over 300 ft. The glacial features in In Ingham County, erosion removed most of the Grand River Michigan are the result of ice advances during late Wisconsin Formation, and as a result only a few large remnants remain time (35,000 to 10,000 years before present). Glacial deposits (Vanlier and others, 1973). These assignments between forma‑ are of three principal types: 1) a well‑sorted mixture of silt, tions are somewhat uncertain, however, because no lithologic sand, and gravel, such as valley outwash, outwash plains, differences or stratigraphic horizons mark a change from one eskers, kames, and buried outwash, deposited by streams formation to the next (Westjohn and Weaver, 1996a). The of melt water draining from glaciers, 2) a layered sequence Pennsylvanian bedrock unit ranges in thickness from 0 to over of silt, sand, and clay deposited in glacial lakes, and 3) an 400 ft and is absent in the extreme eastern part of Ingham unsorted mixture of clay, silt, sand, gravel, and boulders, such County. as till, deposited directly from the melting ice (Vanlier and The basal part of the Pennsylvanian Saginaw Forma‑ others, 1973). None of these deposits are regionally continu‑ tion is considered to be the Parma Sandstone although the ous (Mandle and Westjohn, 1989). stratigraphic relationship is not clear between the Saginaw Glacial deposits are the uppermost aquifer in Ingham Formation, Parma Sandstone, and the underlying Bayport County. Ground‑water flow in the glacial deposits is gener‑ Limestone. The Parma Sandstone is composed of medium‑ to ally from south to north, away from topographic divides and coarse‑grained sandstone and is generally less than 100 ft towards surface‑water bodies. Aquifers in the glacial deposits thick (Cohee and others, 1951). Interpretation of geophysi‑ are composed of coarse alluvial and outwash materials. A cal logs indicates that the lower part of the Pennsylvanian large outwash area is south of Dansville in Ingham County. rock sequence is predominantly shale, whereas the upper part This outwash area varies in thickness and is primarily fine is predominantly sandstone. Thus, the Pennsylvanian rocks sand, although some is coarse sand and gravel. Long narrow younger than the Parma Sandstone can be divided into a lower ridges of sand and gravel, called eskers, are present in Ingham confining unit and an upper sandstone aquifer (Westjohn and County. Esker deposits yield water to municipal wells in Wil‑ Weaver, 1996a). liamston and, historically, in Mason. Buried outwash deposits The Saginaw aquifer is in the water‑bearing sand‑ were formed as areas of outwash deposited by a preceding stones in the Grand River and Saginaw Formations. Most  Summary of Hydrogeologic Conditions by County for the State of Michigan ground‑water flow in the Saginaw aquifer is from south to February 2005 Wellogic database, approximately 84 percent of north, although a small amount is toward local pumping cen‑ the wells in Ionia County are completed in the glacial depos‑ ters. Flow across the western part of Ingham County, where its, and 14 percent in the bedrock units. There is insufficient the sandstone of the Saginaw Formation is very thin or absent, information to make this distinction for 2 percent of the wells is minimal. The Saginaw aquifer is recharged principally by in the county. leakage from the glacial deposits. Ground water also dis‑ Glacial aquifers consist of sand and gravel that are part charges locally from bedrock to the glacial deposits beneath of a thick sequence of Pleistocene glacial deposits. With the valleys of major streams (Holtschlag and others, 1996). The available information, glacial lithologies cannot be regionally Grand River and Saginaw Formations act as a single hydro‑ correlated in the subsurface. This is likely due to the lateral logic unit, so the chemical characteristics of water in these for‑ and vertical heterogeneity of glacial deposits that resulted mations are very similar. Nearly all wells tapping these forma‑ from a complex depositional history (Westjohn and others, tions yield water that is suited to household needs. The water 1994). The glacial deposits in Ionia County are 0 to 500 ft is generally hard or very hard and contains iron, although, in thick. Glacial deposits in the county are primarily composed some localities, the Saginaw Formation yields soft water (Van‑ of till and outwash. Till may be found in moraines or till lier and others, 1973). Analyses of aquifer‑test data indicate plains (Swanson, 1970). Moraines generally trend north to a wide range of transmissivities within the Saginaw aquifer. south in the county. Till is a poorly sorted mixture of clay, Wood (1969) reported that pumping tests indicated a relatively silt, sand, gravel, and boulders. The majority of till is fine‑ to constant permeability of the sandstone in the Saginaw Forma‑ medium‑grained in Ionia County (Farrand and Bell, 1982). tion of about 100 gpd/ft2 (13 ft/day). The permeability of the Outwash is composed of sand and gravel and is generally shale is more variable, ranging from 0.01 to 1.0 gpd/ft2 (0.001 the most productive glacial deposit. The glacial wells gener‑ to 0.13 ft/day) (Wood, 1969). Transmissivities that range from ally tap buried outwash and primarily occur on till plains and 130 to 2,700 ft2/day were reported for the Saginaw aquifer for moraines (Swanson, 1970). According to the Public Water the three‑county area of Clinton, Ingham, and Eaton Counties Supply database, the estimated transmissivity for a glacial by Vanlier and Wheeler (1968). This range in transmissivi‑ well is approximately 2,305 ft2/day. The quality of water from ties reflects variations in the total thickness of the sandstone glacial wells varies. However, glacial wells may supply hard beds in the formation and variations in the permeability of the water that is high in iron (Swanson, 1970). sandstone. Measured porosities and matrix‑controlled vertical From youngest to oldest, the Jurassic “red beds”, Grand hydraulic conductivities range from 4 to 34 percent and 0.0001 River Formation, Saginaw Formation, Bayport Limestone, and to 55 ft/day, respectively (Westjohn and Weaver, 1996a). Michigan Formation form the bedrock surface in the county. Underlying the Saginaw Formation are beds of Missis‑ The Jurassic “red beds” are also dispersed in portions of Ionia sippian age – (Bayport Limestone and Michigan Formation). County. In Ionia County the “red beds” are often located on The Bayport Limestone is a fossiliferous, cherty limestone, topographically high areas (Swanson, 1970). Where the “red often with interbedded sandstone and varies considerably in beds” are present, the unit was deposited after bedrock and thickness from one area to another. The Bayport Limestone prior to glacial deposits. The Jurassic “red beds” generally and Parma Sandstone appear to interfinger throughout the range from 50 to 150 ft in thickness when present, and may Michigan Basin. These units are hydraulically connected, and be up to 200 ft thick. The “red beds” are often poorly consoli‑ together they form the Parma‑Bayport aquifer (Westjohn and dated or unconsolidated and consist primarily of clay, mud‑ Weaver, 1996a). Please note that due to the uncertainty of stone, siltstone, sandstone, shale, and gypsum. The “red beds” stratigraphic relationship between these units, in other reports are relatively impermeable and are considered a confining this aquifer may be delineated differently. The Michigan unit. The “red beds” impede the vertical flow of water between Formation is composed primarily of shale but includes beds of the glacial and bedrock aquifers (Westjohn and others, 1994). sandstone, limestone, and gypsum (Vanlier and others, 1973). The water in the “red beds” is generally highly mineralized The Michigan Formation is generally impermeable and con‑ (Swanson, 1970). sidered to be a confining unit (Westjohn and Weaver, 1998). The Pennsylvanian bedrock units in Ionia County include Both the Bayport and Michigan Formations yield saline water the Grand River and Saginaw Formations. The Grand River where they are overlain by the Saginaw Formation. Wells Formation is composed of primarily sandstone, but also tapping aquifers in these formations in Ingham County yield contains shale and conglomerate. In Ionia County, the Grand water too hard and too highly mineralized for domestic use River Formation is up to 100 ft thick, but is generally thinner. (Stuart, 1945). In Ionia County, the Saginaw Formation is up to 100 ft thick (Swanson, 1970). The Saginaw Formation consists of discon‑ tinuous layers of shale, coal, sandy shale, sandstone, lime‑ Ionia County stone, and sandstone (Swanson, 1970; Westjohn and Weaver, 1998). The Parma Sandstone is often considered the basal Ionia County is in the south‑central Lower Peninsula unit of the Saginaw Formation, although the stratigraphic of Michigan. The Maple, lower Grand, upper Grand, and relationship is not clear between the Saginaw Formation, Thornapple watersheds drain Ionia County. According to the Parma Sandstone, and underlying Mississippian‑aged Bayport County Summaries 

Limestone. The Parma Sandstone is composed of medium‑ to stratigraphically continuous permeable sandstones. The upper coarse‑grained sandstone, and is generally less than 100 ft sandstone is a quartzarenite to sublitharenite that is referred to thick (Cohee and others, 1951). as the Napoleon Sandstone Member. A shale, siltstone, and/or The Pennsylvanian bedrock above the Parma Sandstone carbonate layer separates the Napoleon Sandstone Member can be divided into an upper sandstone aquifer and a lower from the underlying lower Marshall sandstone. The lower confining unit. The Saginaw aquifer is in the sandstones Marshall sandstone is comprised of two units. The upper unit from the Grand River and Saginaw Formations. The Saginaw is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ aquifer ranges in thickness from less than 100 to 370 ft within enite to sublitharenite. At the base of the Marshall Sandstone the State (Westjohn and Weaver, 1996a). According to the is a fine‑ to medium‑grained litharenite that ranges in thick‑ Public Water Supply database, the estimated transmissivity for ness from 30 to 125 ft. Permeable sandstones in the Marshall wells completed in the Grand River and Saginaw Formations Sandstone comprise the Marshall aquifer. The Marshall aqui‑ in the county ranges from approximately 250 to 1,020 ft2/day. fer ranges in thickness from 75 to greater than 200 ft within Hard to very hard water may be withdrawn from the Sagi‑ the State (Westjohn and Weaver, 1998). The Marshall aquifer naw Formation (Swanson, 1970). The Saginaw aquifer yields is capable of supplying large quantities of water. The Marshall both saline and fresh water in Ionia County (Westjohn and aquifer yields both saline water and brine in Ionia County Weaver, 1996c). In Ionia County, where the Saginaw Forma‑ (Westjohn and Weaver, 1996c). In Ionia County, shallower tion yields good quality water, the Saginaw Formation is used aquifers supply higher quality water than the Marshall aquifer. as an aquifer preferentially over the glacial aquifer (Swanson, Coldwater Shale underlies the Marshall Sandstone. 1970). The Saginaw confining unit underlies the Saginaw Coldwater Shale consists of primarily shale with interbeds or aquifer. The Saginaw confining unit is approximately 50 to lenses of sandstone, siltstone, and dolomite. Coldwater Shale 100 ft thick in the county, and is mostly shale, with thin layers is relatively impermeable and is considered a confining unit in of discontinuous sandstone, siltstone, limestone, and coal. The most of Michigan and the bottom layer of the regional aquifer permeable layers within the Saginaw confining unit appear to system (Westjohn and Weaver, 1998). be isolated from the regional ground‑water‑flow system (West‑ john and Weaver, 1996a). The Saginaw confining unit separates the Saginaw Iosco County aquifer from the underlying Parma‑Bayport aquifer. Bedrock Iosco County is in the northeastern portion of the Lower of Mississippian age underlies the Saginaw Formation. This Peninsula. The Saginaw Lowlands extend from the southwest includes the Bayport Limestone, Michigan Formation, Mar‑ to northwest along the southeastern portion of the county. shall Formation, and Coldwater Shale. The Bayport Limestone The Lone Lake‑Ocqueoc, Au Sable, Au Gres‑Rifle, and Lake is a fossiliferous, cherty limestone, often with interbedded Huron watersheds drain through the county. According to the sandstone. In Ionia County, Bayport Limestone is 0 to 50 ft February 2005 Wellogic database, approximately 74 percent thick (Swanson, 1970). The Bayport Limestone and Parma of the wells in Iosco County are completed in the glacial Sandstone appear to interfinger throughout the Michigan deposits, and 22 percent in the bedrock units. There is insuf‑ Basin. These units are hydraulically connected, and together ficient information to make this distinction for 4 percent of the they form the Parma‑Bayport aquifer (Westjohn and Weaver, wells in the county. The bedrock wells are concentrated in the 1996a). The Parma‑Bayport aquifer is approximately 100 to south‑central portion of the county. 150 ft thick within the Michigan Basin. Please note that due In the Michigan Basin, glacial aquifers consist of sand to the uncertainty of stratigraphic relationship between these and gravel that are part of a thick sequence of Pleistocene units, in other reports this aquifer may be delineated differ‑ glacial deposits. With the available information, glacial ently. In Ionia County, the Parma‑Bayport aquifer yields saline lithologies cannot be regionally correlated in the subsurface. water or brine (Westjohn and Weaver, 1996c). This is likely due to the lateral and vertical heterogeneity of The Michigan Formation underlies Bayport Limestone. glacial deposits that resulted from a complex depositional his‑ The Michigan Formation consists of layers of sandstone, tory (Westjohn and others, 1994). The thickness of the glacial siltstone, anhydrite or gypsum, dolomite, limestone, and deposits ranges between 11 and 800 ft within the county, and shale. The Michigan Formation is generally impermeable and generally decreases from north to south (Western Michigan considered a confining unit (Westjohn and Weaver, 1998). University, 1981). Lacustrine deposits, till, and outwash com‑ However, in Ionia County, the sandstone may provide small pose the glacial deposits in Iosco County. Lacustrine deposits amounts of water to wells. The water obtained from the Michi‑ are the most abundant glacial deposit in the county, and are gan Formation is often mineralized from the abundance of primarily coarse grained, except for in the southeast portion of gypsum in the formation. The water may also be saline. Good the county, where the lacustrine deposits are fine grained. Till quality water may be obtained when the shallow sandstones is primarily fine grained; however, in the north‑central portion of the Michigan Formation are significantly separated from of there is an area of county medium‑ and coarse‑grained till. gypsum units by shale layers (Swanson, 1970). The outwash deposits are composed of sand and gravel and The Marshall Sandstone underlies the Michigan For‑ occur in the northwestern portion of the county. Ice‑contact mation. The Marshall Sandstone consists of one or more  Summary of Hydrogeologic Conditions by County for the State of Michigan outwash is present in the central portion of the county (Farrand northern portion of Iosco County, respectively (Westjohn and and Bell, 1982). According to the Public Water Supply data‑ Weaver, 1996c) base, the estimated transmissivity for glacial wells in Iosco The Coldwater Shale underlies the Marshall Sandstone. County ranges from approximately 3,530 to 4,145 ft2/day. The Coldwater Shale consists of primarily shale with interbeds In the northeastern portion of Iosco County, in the Au or lenses of sandstone, siltstone, and dolomite. The Coldwa‑ Sable watershed, is the location of the Wurtsmith Air Force ter Shale is considered a confining unit in most of Michigan base. In this area, the glacial aquifer is contaminated with (Westjohn and Weaver, 1996b). volatile organic hydrocarbons. The generally unconfined aquifer consists of a medium to coarse‑grained sand with some gravel. The aquifer extends from the surface to 80 to Iron County 30 ft underground, in the northern and western areas of the Iron County is in the southwestern portion of the Upper base, respectively. The average thickness of the aquifer is 65 Peninsula of Michigan. The Ontonagon, Brule, Sturgeon, ft. In the northern part of the area, the aquifer also contains Michigamme, Menominee, Cedar‑Ford, and Upper Wisconsin thin clay layers generally 5 to 15 ft below the surface. A clay watersheds drain Iron County. Ninety percent of the county’s unit underlies the glacial aquifer (Stark and others, 1983; surface is covered in glacial deposits. The rest is composed of Cummings and Twenter, 1986). The clay unit dips to the east post‑glacial swamp deposits and bedrock. The availability of and the exact thickness is unknown, but may be greater than ground water is not uniform within the county (Doonan and 250 ft in areas (Stark and others, 1983). Water levels in the Hendrickson, 1967). According to the February 2005 Wel‑ aquifer at Wurtsmith Air Force base range between 10 to 25 ft logic database, approximately 69 percent of the wells in Iron below the ground surface, and fluctuate 1 to 3 feet annually. A County are completed in the glacial deposits, and 27 percent ground‑water divide extends from the northeast to southwest in the bedrock units. There is insufficient information to make across the base. Ground water flows to the east north of the this distinction for 4 percent of the wells in the county. divide and to the south, south of the divide (Stark and others, Aquifers in the glacial deposits consist largely of sands 1983; Cummings and Twenter, 1986). The transmissivity and and gravels and vary regionally in thickness and permeability. specific yield of the glacial aquifer at Wurtsmith Air Force The glacial deposits in Iron County consist of moraines and till Base was estimated from an aquifer test and ranges from 5,000 plains, composed primarily of till, and outwash deposits. The to 20,000 ft2/day and 0.2, respectively. The hydraulic conduc‑ thickness of the glacial deposits ranges from 0 to hundreds tivity was estimated from an aquifer test and specific capac‑ of feet thick. Glacial deposits in the county include till and ity tests and ranges from 16 to 310 ft/day (Stark and others, outwash. In general, the glacial deposits can be divided into 1983). two sections in Iron County which were deposited from differ‑ Bedrock underlies the glacial deposits. The bedrock ent glacial events. The glacial deposits in the southern portion surface of Iosco County is composed the Michigan Formation, of the county are primarily older and lack terminal moraines. Marshall Sandstone, and Coldwater Shale (Milstein, 1987). Also in the south, eskers and drumlins are common with The Michigan Formation consists of layers of sandstone, the older glacial deposits overlain in some areas by younger siltstone, anhydrite or gypsum, dolomite, limestone, and shale. glacial deposits. The northern part of the county consists of The lower permeability lithologies of the Michigan Formation the younger glacial deposits, but lacks drumlins. Lenses of are considered a confining unit. The thickness of the Michigan sand and gravel occur locally in drumlins that are primarily confining unit ranges from less than 50 to 400 ft within the composed of till. Eskers are composed of till, but tend to be State (Westjohn and Weaver, 1998). richer in boulders (Stuart and others, 1948). Moraines are gen‑ The Marshall Sandstone underlies the Michigan For‑ erally composed of till, consisting of boulders, cobbles, gravel, mation. The Marshall Sandstone consists of one or more sand, silt, and clay. Small to moderate yields of water may be stratigraphically continuous permeable sandstones. The upper obtained from wells completed in moraine deposits. The water sandstone is a quartzarenite to sublitharenite that is referred to is moderately hard to hard and contains small to moderate as the Napoleon Sandstone Member. A shale, siltstone, and/or amounts of iron. Till plains in Iron County, generally consist carbonate layer separates the Napoleon Sandstone Member of sandy, clayey till with boulders. Till‑plain wells generally from the underlying lower Marshall sandstone. The lower yield small supplies of water that is low in iron and is moder‑ Marshall sandstone is comprised of two units. The upper unit ately hard to hard. The largest outwash plain is located south is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ of Crystal Falls. Narrower areas of outwash also occur in the enite to sublitharenite. At the base of the Marshall Sandstone county. The outwash is comprised of mostly sand and gravel. is a fine‑ to medium‑grained litharenite that ranges in thick‑ Specific capacities range from 0.1 to 28 gal/min/ft in the ness from 30 to 125 ft. Permeable sandstones in the Marshall glacial outwash. Outwash wells generally provide the largest Sandstone comprise the Marshall aquifer. The Marshall yields of water. The water from outwash wells is moderately aquifer ranges in thickness from 75 to greater than 200 ft hard to very hard, and a few wells have high iron content within the State (Westjohn and Weaver, 1998). The Marshall (Doonan and Hendrickson, 1967). According to Stuart and Sandstone yields saline and fresh water in the southern and others (1948), the estimated transmissivity for the glacial wells County Summaries  from aquifer tests range from approximately 10,000 to 32,000 consists of hydraulically connected sandstones in the Saginaw ft2/day. The storage coefficient ranges from 0.0007 to 0.207 in Formation (Westjohn and Weaver, 1998). Within the State, the the glacial aquifer (Stuart and others, 1948). According to the Saginaw aquifer ranges between less than 100 to 370 ft thick, Public Water Supply database, the estimated transmissivity for and yields both fresh and saline water. The Saginaw aquifer glacial wells ranges from approximately 725 to 53,475 ft2/day. yields fresh water in the southeastern corner of the county. In Bedrock in Iron County is mostly igneous and metamor‑ the rest of Isabella County, the Saginaw aquifer yields saline phic Precambrian rocks. There are outcrops along the Michi‑ water (Westjohn and Weaver, 1996c). The Saginaw confining gamme River and dispersed throughout the county. In general, unit underlies the Saginaw aquifer. The Saginaw confining bedrock wells only supply small quantities of water that is unit is approximately less than 100 to 240 ft thick within the moderately hard to hard, and contain low amounts of iron State, and is mostly shale, with thin layers of discontinuous (Doonan and Hendrickson, 1967). sandstone, siltstone, limestone, and coal. The permeable layers within the Saginaw confining unit appear to be isolated from the regional ground‑water‑flow system (Westjohn and Weaver, Isabella County 1996a). Isabella County is in the central part of the Lower Penin‑ sula of Michigan. The Tittabawassee, Pine, and Lower Grand Jackson County River watersheds drain Isabella County. According to the February 2005 Wellogic database, approximately 99 percent Jackson County is in the southern portion of the Lower of the wells in Isabella County are completed in the glacial Peninsula of Michigan. The Kalamazoo, Upper Grand, Huron, deposits, and less than 1 percent in the bedrock units. There is and Raisin watersheds drain the county in the southwestern, insufficient information to make this distinction for 1 percent north and central, eastern edge, and southeastern portions of of the wells in the county. the county, respectively. The Upper Grand watershed covers In the Michigan Basin, glacial aquifers consist of sand the majority of the county, while the Huron watershed drains and gravel that are part of a thick sequence of Pleistocene a small portion of the county on the eastern side. According glacial deposits. With the available information, glacial to the February 2005 Wellogic database, approximately 12 lithologies cannot be regionally correlated in the subsurface. percent of the wells in Jackson County are completed in the This is likely due to the lateral and vertical heterogeneity of glacial deposits, and 74 percent in the bedrock units. There is glacial deposits that resulted from a complex depositional insufficient information to make this distinction for 14 percent history (Westjohn and others, 1994). Glacial deposits are of the wells in the county. The main bedrock aquifers are the approximately 150 to 600 ft thick in Isabella County (Western Saginaw and Marshall aquifers (Vanlier, 1968). Michigan University, 1981). The glacial deposits are com‑ In the Michigan basin, glacial aquifers consist of sand posed of till, outwash and lacustrine deposits. The till deposits and gravel that is part of a thick sequence of Pleistocene gla‑ are generally medium‑ to coarse‑textured material but can cial deposits. With the available information, glacial litholo‑ range from clay to boulder size. These deposits are found in gies cannot be regionally correlated in the subsurface. This is the three separate moraines that are along the west side of the likely due to the lateral and vertical heterogeneity of glacial county. In between those three moraines are glacial outwash deposits that resulted from a complex depositional history deposits. These outwash deposits are composed of sand and (Westjohn and others, 1994). The glacial deposits in Jackson gravel material. Both sand and gravel, as well as, clay and silt County are generally 100 ft thick or less. Glacial deposits dominated lacustrine deposits are present in eastern edge of include outwash, moraines, and till plains (Vanlier, 1968). In the county (Farrand and Bell, 1982). According to the Public Jackson County, there is an abundance of outwash interspersed Water Supply database, the estimated transmissivity for glacial throughout the county (Vanlier, 1968; Farrand and Bell, 1982). wells ranges from approximately 1,630 to 20,160 ft2/day. Glacial outwash is generally very permeable and composed The bedrock surface of Isabella County is composed of of sand and gravel. Moraines and till plains are composed of the Jurassic “red beds” and the Saginaw Formation (Milstein, till. Till is mixture of clay, silt, sand, and gravel, which often 1987) which both underlie the glacial deposits. The Jurassic has lower permeability (Vanlier, 1968). The till in Jackson “red beds” are generally 50 to 150 ft thick (Westjohn and oth‑ County is medium to coarse grained (Farrand and Bell, ers, 1994). The “red beds” occur primarily in the southern por‑ 1982). Moraines and till plains may contain lenses of outwash tion of the county (Milstein, 1987). The “red beds” consist of (Vanlier, 1968). Glacial wells may supply water that is hard to red clay, mudstone, siltstone, and sandstone, and also include very hard and contain objectionable amounts of iron (Vanlier, gray‑green shale, gypsum, and mudstone (Shaffer, 1969). The 1968). “red beds” are considered as a confining unit in Michigan Bedrock underlies the glacial deposits. The Saginaw (Westjohn and others, 1994). Where the “red beds” are pres‑ Formation, Bayport Limestone, Michigan Formation, Marshall ent, the Saginaw Formation underlies the Jurassic deposits. Sandstone, and Coldwater Shale form the bedrock surface of Interbedded sandstone, siltstone, shale, coal, and lime‑ Jackson County. The Saginaw Formation contains interbeds of stone compose the Saginaw Formation. The Saginaw aquifer discontinuous sandstone, siltstone, limestone, coal, and shale  Summary of Hydrogeologic Conditions by County for the State of Michigan

(Westjohn and Weaver, 1998). The sandstone in the Saginaw Sandstone comprise the Marshall aquifer. The Marshall aqui‑ Formation is the Saginaw aquifer. The Saginaw aquifer ranges fer ranges in thickness from 75 to greater than 200 ft within in thickness from less than 100 to 370 ft in thickness in the the State (Westjohn and Weaver, 1998). The Marshall aquifer State. The Saginaw aquifer is utilized in the northern portion generally supplies water to the southern portion of Jackson of Jackson County (Westjohn and Weaver, 1998). Here, the County (Vanlier, 1968). Transmissivity values in Jackson Saginaw aquifer yields soft to very hard, fresh water (Vanlier, County are between 7,500 and 29,000 ft2/day. The Marshall 1968; Westjohn and Weaver, 1996c). The Saginaw confining aquifer yields fresh water in the majority of Jackson County, unit underlies the Saginaw aquifer. The Saginaw confining except in the north‑central portion of the county where it unit is approximately 50 ft in thickness and is mostly shale, yields saline water (Westjohn and Weaver, 1996c). with thin layers of sandstone, siltstone, limestone, and coal Underlying the Marshall Sandstone is the Coldwater (Westjohn and Weaver, 1996a). Shale. The Coldwater Shale consists of shale, sandstone, The Saginaw confining unit separates the Saginaw siltstone, and carbonates. This is considered to be a confining aquifer from the underlying Parma‑Bayport aquifer. The unit and ranges in thickness, from east to west across the State, Parma Sandstone is often considered the basal unit of the Sagi‑ between 500 and 1,300 ft thick (Westjohn and Weaver, 1998). naw Formation, although the stratigraphic relationship is not clear between the Saginaw Formation, Parma Sandstone, and Mississippian‑aged Bayport Limestone. The Parma Sandstone Kalamazoo County is composed of medium‑ to coarse‑grained sandstone, and Kalamazoo County is in the southwestern Lower Penin‑ is generally less than 100 ft thick (Cohee and others, 1951). sula of Michigan. The Kalamazoo, Paw Paw, and St. Joseph The Bayport Limestone is a fossiliferous, cherty limestone, watersheds cross the county. The Kalamazoo River drains often with interbedded sandstone and varies considerably the northern two‑thirds, the Paw Paw River drains a small in thickness from one area to another. The Bayport Lime‑ part of the western section, and the St. Joseph River drains stone and Parma Sandstone appear to interfinger throughout the remaining southern part of the county. According to the the Michigan Basin (Westjohn and Weaver, 1996a). These February 2005 Wellogic database, approximately 95 percent units are hydraulically connected, and together they form of the wells in Kalamazoo County are completed in the glacial the Parma‑Bayport aquifer (Westjohn and Weaver, 1996a). deposits, and 2 percent in the bedrock units, which are located The Parma‑Bayport aquifer is approximately 100 to 150 ft primarily in the northeastern portion of the county. There is thick within the Michigan Basin. Please note that due to the insufficient information to make this distinction for 3 percent uncertainty of stratigraphic relationship between these units, of the wells in the county. in other reports this aquifer may be delineated differently. Glacial deposits range in thickness from less than 40 ft Not much information is available on this aquifer because along the Kalamazoo River to more than 600 ft in the western it is not often used as a water supply in the State (Westjohn part of the county. The glacial deposits in Kalamazoo County and Weaver, 1996a). In Jackson County, the water from the are composed of till plains, upland moraines, outwash plains, Parma‑Bayport aquifer may be saline (Westjohn and Weaver, and downcut glacial drainage channel (Rheaume, 1990). 1996c). Monaghan and others (1983) describe the till as varying from The Michigan Formation underlies the Bayport Lime‑ mostly clay to primarily sand. Two morainic systems are stone. The Michigan Formation consists of layers of sand‑ present in Kalamazoo County, the Tekonsha and Kalamazoo stone, siltstone, anhydrite or gypsum, dolomite, limestone, Moraines. The Tekonsha Moraine is just south of the Kal‑ and shale. The lower permeability lithologies of the Michigan amazoo River Valley from Galesburg east toward Calhoun Formation are considered a confining unit that separates the County and consists of massive to poorly bedded, coarse sand Parma‑Bayport aquifer from the underlying Marshall aquifer. to sandy‑clay till, and at places, as massive to poorly bedded The thickness of the Michigan confining unit ranges from sand and gravel containing boulders and cobbles (Monaghan less than 50 to 400 ft within the State (Westjohn and Weaver, and others, 1983). The Kalamazoo Moraine is along the west‑ 1998). ern edge of the county and rises more than 100 ft above the The Marshall Sandstone underlies the Michigan Forma‑ outwash plain in some places (Rheaume, 1990). The moraine tion. The Marshall Sandstone consists of one or more strati‑ forms one of the longest continuous ridges in southern Michi‑ graphically continuous permeable sandstones. The upper gan and has been traced for a distance of over 80 mi (Leverett sandstone is a quartzarenite to sublitharenite that is referred to and Taylor, 1915). Monaghan and others (1983) describe the as the Napoleon Sandstone Member. A shale, siltstone, and/or Kalamazoo Moraine as sandy to very sandy till and massive to carbonate layer separates the Napoleon Sandstone Member poorly bedded cobbly sand. The outwash plains are referred to from the underlying lower Marshall sandstone. The lower as the Climax‑Scotts outwash plain and the Galesburg‑Vicks‑ Marshall sandstone is comprised of two units. The upper unit burg outwash plain and consist of medium‑ to very‑coarse is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ sand and gravel (Monaghan and others, 1983). The downcut enite to sublitharenite. At the base of the Marshall Sandstone glacial drainage channel was formed in the area of the Kal‑ is a fine‑ to medium‑grained litharenite that ranges in thick‑ amazoo River and consists of medium‑ to very‑coarse sand ness from 30 to 125 ft. Permeable sandstones in the Marshall County Summaries  and gravel with some layers of clayey silt (Monaghan and shall Formation for domestic supply where it is overlain by others, 1983). Kehew and others (1999) studied tunnel valleys glacial deposits in Kalamazoo County. in southwestern Michigan. Tunnel valleys are formed when subglacial water, which is often under immense hydrostatic pressure, seeks an outlet (Sugden and John, 1976). Tunnel val‑ Kalkaska County leys in the Kalamazoo County area may be important relative Kalkaska County is located in the northwestern portion of to aquifer occurrence. the Lower Peninsula of Michigan. The Muskegon, Manistee, Aquifers in the glacial deposits consist largely of sands Boardman‑Charlevoix, and Au Sable watersheds cross the and gravels and vary regionally in thickness and permeability. county. According to the February 2005 Wellogic database, Aquifers underlying the outwash plains and the downcut gla‑ approximately 99 percent of the wells in Kalkaska County are cial drainage channels, which together cover about two‑thirds completed in the glacial deposits, and 0 percent in the bedrock of the county, are the most productive (Rheaume, 1990). Allen units. There is insufficient information to make this distinction and others (1972) identified an upper unconfined aquifer for 1 percent of the wells in the county. throughout most of the county and one to two lower semicon‑ In the Michigan Basin, glacial aquifers consist of sand fined aquifers over about one‑third of the county. The ground and gravel that are part of a thick sequence of Pleistocene water is generally of high quality, although the water is hard glacial deposits. With the available information, glacial and generally has objectionably high iron content (Allen and lithologies cannot be regionally correlated in the subsurface. others, 1972). At many locations, the hydraulic connection is This is likely due to the lateral and vertical heterogeneity of good enough that, under pumping conditions, water will move glacial deposits that resulted from a complex depositional readily between aquifers. The transmissivity values for the history (Westjohn and others, 1994). Generally, the glacial sand and gravel aquifers range from 1,250 to 57,200 ft2/day. deposits in Kalkaska County range from 401 to 600 ft thick. Bedrock underlies the glacial deposits. The bedrock sur‑ However, the thickness of the glacial deposits spans from 201 face of the county consists primarily of the Coldwater Shale, to 1,000 ft in the county (Western Michigan University, 1981). with the Marshall Formation comprising the upper bedrock Glacial deposits in Kalkaska County include outwash, till, and surface in the northeastern part of the county. The Coldwater lacustrine deposits. The most abundant glacial deposit in the Shale is 500 ft or more thick in the Kalamazoo County area county is sand and gravel outwash. Ice‑contact outwash that is and gently dips northeastward (Deutsch and others, 1960). The dominated by poorly sorted sand and gravel is present in the Coldwater Shale primarily is composed of shale that contains western and southern part of the county. Coarse‑grained till is limestone and clayey limestone in some areas (Rheaume, found in a moraine that trends southwest to northeast in por‑ 1990). Water from the Coldwater Shale unit is highly mineral‑ tions of the western half of the county. The northwest corner ized and yields are small; therefore, the Coldwater Shale is not of Kalkaska County is composed of sand and gravel lacustrine generally used for water supply. The Coldwater Shale grades deposits. Post‑glacial dune sand deposits also are present in upward into the Marshall Formation. The Marshall Forma‑ areas of the county, and are small in aerial extent (Farrand tion directly overlies the Coldwater shale in the northeastern and Bell, 1982). Glacial wells in the county, according to the part of Kalamazoo County, and has been eroded away in Public Water Supply database, have estimated transmissivi‑ the rest of the county (Deutsch and others, 1960). The Mar‑ ties from aquifer tests that range from approximately 12,400 shall Formation in the county is composed of gray to white to 33,954 ft2/day. Bedrock underlies the glacial deposits in the sandstone that consists of rounded to subangular grains of county, but is not currently used for water supply. very fine to medium sand in alternating soft and hard layers (Passero, 1983). The Marshall aquifer consists of one or more stratigraphically continuous permeable sandstones. In areas Kent County where the Marshall aquifer consists of two or more sand‑ stones, these permeable strata typically are separated by beds Kent County is in the western south‑central Lower Penin‑ of siltstone, shale and (or) carbonate (Westjohn and Weaver, sula of Michigan. The Kalamazoo, Lower Grand, Thornapple, 1996b). A range of transmissivity values, 0 to 15,000 ft2/day, and Muskegon watersheds drain the county. Water supplies were estimated for the upper sandstone aquifer in the Marshall are obtained from surface water and ground water. Accord‑ Sandstone in nearby Calhoun County from constant hydraulic ing to the February 2005 Wellogic database, approximately conductivities of 150 ft/day and a thickness from 0 to 100 ft. 94 percent of the wells in Kent County are completed in the Also, in Calhoun County, a pumping test was performed on glacial deposits, and 4 percent in the bedrock units. There is the lower sandstone aquifer. A transmissivity of 25,000 ft2/day insufficient information to make this distinction for 2 percent and a storage coefficient of 1.5 x 10‑5 were estimated from of the wells in the county. the aquifer test. Transmissivity values ranging from 3,000 to In the Michigan Basin, the glacial aquifer consists of 27,000 ft2/day were estimated for the lower sandstone aquifer sand and gravel that is part of a thick sequence of Pleisto‑ from constant hydraulic conductivities of 550 ft/day and a cene glacial deposits. With the available information, glacial thickness from 5 to 50 ft (Grannemann and Twenter, 1985). lithologies cannot be regionally correlated in the subsurface. Sufficient quantities of water can be withdrawn from the Mar‑ This is likely due to the lateral and vertical heterogeneity of  Summary of Hydrogeologic Conditions by County for the State of Michigan glacial deposits that resulted from a complex depositional The Saginaw aquifer consists of the sandstones in the Saginaw history (Westjohn and others, 1994). The thickness of glacial Formation (Westjohn and Weaver, 1998). The water from the deposits ranges from 11 to 800 ft in Kent County. However, Saginaw aquifer is usually high in iron and hard (Stramel and the majority of glacial deposits range from 201 to 400 ft in others, 1954). The Saginaw aquifer yields saline water in Kent thickness (Western Michigan University, 1981). The glacial County (Westjohn and Weaver, 1996c). The Saginaw confin‑ deposits in the county include till, outwash, and lacustrine ing unit underlies the Saginaw aquifer. The Saginaw confin‑ deposits. Till occurs in moraines and till plains, and are inter‑ ing unit is less than 100 to 240 ft thick within the State, and spersed on the surface throughout the county (Stramel and is mostly shale, with thin layers of discontinuous sandstone, others, 1954; Farrand and Bell, 1982). Till is composed of fine siltstone, limestone, and coal. The permeable layers within the to coarse‑grained material, including silt, sand, gravel, and Saginaw confining unit appear to be isolated from the regional boulders; however, the majority of the till in Kent County is ground‑water‑flow system (Westjohn and Weaver, 1996a). medium‑grained (Farrand and Bell, 1982). In the Grand Rap‑ The Saginaw confining unit separates the Saginaw aqui‑ ids area, moraines and till‑plain deposits may provide small fer from the underlying Parma‑Bayport aquifer. The Parma quantities of water (Stramel and others, 1954). According to Sandstone is often considered the basal unit of the Saginaw the Public Water Supply database, the estimated transmissiv‑ Formation, although the stratigraphic relationship is not ity for wells tapping medium‑textured glacial till ranges from clear between the Saginaw Formation, Parma Sandstone, and approximately 2,350 to 48,845 ft2/day in Kent County. Out‑ Mississippian‑aged Bayport Limestone. The Parma Sandstone wash is the most permeable of the glacial deposits, and con‑ is composed of medium‑ to coarse‑grained sandstone, and sists of sand and gravel. Outwash consists of sand and gravel, is generally less than 100 ft thick (Cohee and others, 1951). and also is distributed throughout the county (Farrand and The Bayport Limestone is a fossiliferous, cherty limestone, Bell, 1982). In the Grand Rapids area, the outwash ranges in often with interbedded sandstone and varies considerably thickness from 0 to 90 ft. According to the Public Water Sup‑ in thickness from one area to another. The Bayport Lime‑ ply database, the estimated transmissivity for wells completed stone and Parma Sandstone appear to interfinger throughout in the outwash in the county, ranges from approximately 5,700 the Michigan Basin (Westjohn and Weaver, 1996a). These to 962,640 ft2/day. Stramel and others (1954) observed thin units are hydraulically connected, and together they form layers of lacustrine deposits in the Grand Rapids area. In the the Parma‑Bayport aquifer (Westjohn and Weaver, 1996a). area, lacustrine deposits consist of clay and fine‑grained sand, The Parma‑Bayport aquifer is approximately 100 to 150 ft and may be underlain by sand and gravel. In the Grand Rapids thick within the Michigan Basin. Please note that due to the area, water from the glacial wells may be hard (Stramel and uncertainty of stratigraphic relationship between these units, others, 1954). Atrazine has been modeled to leach into the in other reports this aquifer may be delineated differently. In shallow aquifer in areas of Kent County (Holtschlag and Plainfield Township, the Bayport Limestone is known to sup‑ Luukkonen, 1996; 1998). ply large quantities of water (Vanlier, 1968). Bedrock underlies the glacial deposits. The Jurassic “red The Michigan Formation underlies the Bayport Lime‑ beds” form the bedrock surface in portions of Kent County. stone. Shale and gypsum are the primary constituents of the The Jurassic “red beds” generally range between 50 to 150 Michigan Formation, however, lenses of sandstone and lime‑ ft in thickness when present, and may be up to 200 ft thick. stone are also present (Stramel and others, 1954). The Michi‑ Where the “red beds” are present, the unit occurs underly‑ gan Formation has lower permeability, and is generally consid‑ ing glacial deposits and overlying the bedrock surface. The ered a confining unit within the State (Westjohn and Weaver, “red beds” are often poorly consolidated or unconsolidated 1996b). In the central‑western and southwestern portion of the and consist primarily of clay, mudstone, siltstone, sandstone, county, including the Grand Rapids area, the Michigan Forma‑ shale, and gypsum. The “red beds” are relatively imperme‑ tion may supply small to moderate amounts of highly mineral‑ able and are considered a confining unit. However, locally ized water (Stramel and others, 1954; Vanlier, 1968). in the county, the “red beds” may supply small quantities of The Marshall Sandstone underlies the Michigan For‑ water. According to the Public Water Supply database, the mation. The Marshall Sandstone consists of one or more estimated transmissivity for a well completed in the “red beds” stratigraphically continuous permeable sandstones. The upper is approximately 850 ft2/day. The “red beds” impede the verti‑ sandstone is a quartzarenite to sublitharenite that is referred to cal flow of water between glacial and bedrock aquifers. In the as the Napoleon Sandstone Member. A shale, siltstone, and/or west‑central portion of the State, the “red beds” are usually carbonate layer separates the Napoleon Sandstone Member present over the saline‑water‑bearing Pennsylvanian rocks from the underlying lower Marshall sandstone. The lower (Westjohn and others, 1994). Marshall sandstone is comprised of two units. The upper unit From northeast to southwest the Saginaw Formation, is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ Bayport Limestone, Michigan Formation, and Marshall enite to sublitharenite. At the base of the Marshall Sandstone Sandstone form the remainder of the bedrock surface, gener‑ is a fine‑ to medium‑grained litharenite that ranges in thick‑ ally trending northwest to southeast, in the county. Bedrock ness from 30 to 125 ft. Permeable sandstones in the Marshall units dip to the northeast. The Saginaw Formation consists of Sandstone comprise the Marshall aquifer. The Marshall aqui‑ shale, coal, sandy shale, sandstone, limestone, and sandstone. fer ranges in thickness from 75 to greater than 200 ft within County Summaries  the State (Westjohn and Weaver, 1998). The Marshall aquifer capacity data from Doonan and others (1970), an estimated is capable of supplying large quantities of water. According transmissivity for the bedrock aquifer ranges between 4 and to the Public Water Supply database, the estimated transmis‑ 442 ft2/day. In general, the water from the bedrock aquifer is sivity for wells completed in the Marshall aquifer ranges from soft to moderately hard and may contain high iron concentra‑ approximately 560 to 8,635 ft2/day. In the Grand Rapids area, tions. In a few areas, the water from bedrock wells is saline water from the Marshall aquifer is often used for industrial (Doonan and others, 1970). The surface expression of the bed‑ purposes (Stramel and others, 1954). The Marshall Sandstone rock surface in Keweenaw County generally trends northeast yields fresh and saline water, and brine in Kent County (West‑ to southwest and the dip of the bedrock is northwest, except john and Weaver, 1996c). Water from Marshall Sandstone is on Isle Royale where the dip is southeast. The difference in hard, mineralized, and may contain hydrogen sulfide gas in the bedrock dip is the result of the two limbs of a syncline that the northern portion of the Grand Rapids area. These effects runs beneath the western portion of Lake Superior. decrease towards the south (Stramel and others, 1954). The Jacobsville Sandstone forms the bedrock surface The Coldwater Shale underlies the Marshall Sandstone. near the eastern part of the county. Most of the bedrock wells The Coldwater Shale consists of primarily shale with interbeds in the county obtain water from the Jacobsville Sandstone, or lenses of sandstone, siltstone, and dolomite. The Coldwater composed of sandstone, shale, and conglomerate layers. Small Shale is relatively impermeable and water from the unit is to moderate yields of water are supplied from Jacobsville highly mineralized (Stramel and others, 1954). sandstone wells. The quality of the ground water is gener‑ ally acceptable; however, saline water may be tapped in deep wells. Keweenaw County The Freda Sandstone forms the bedrock surface along the north and northwestern portion of Keweenaw County Keweenaw County is in the western Upper Peninsula and along the southeastern shore of Isle Royale. The Freda of Michigan. The Keweenaw Peninsula and Lake Superior Sandstone is an arkose sandstone interbedded with micaceous watersheds drain the county. Keweenaw County does not have shale. Underlying the Freda Sandstone is the Nonesuch Shale, abundant supplies of ground water (Doonan and others, 1970). which is approximately 600 feet thick. Water supplies from the According to the February 2005 Wellogic database, approxi‑ Freda Sandstone and Nonesuch shale are small and tend to be mately 36 percent of the wells in Keweenaw County are com‑ saline. pleted in the glacial deposits, and 60 percent in the bedrock The Copper Harbor Conglomerate includes two lava units. There is insufficient information to make this distinction flows in Keweenaw County, and is exposed on Isle Royale for 4 percent of the wells in the county. and the northern and western shores of Keweenaw County. Aquifers in the glacial deposits consist largely of sands The Copper Harbor Conglomerate is composed of boulder to and gravels and vary regionally in thickness and permeability. pebble‑size clasts and arkose sandstone. Water supplies from The glacial deposits range in thickness from 0 to 312 ft in the the Copper Harbor Conglomerate are small to moderate and county. The glacial deposits consist of morainal, lacustrine, the water may be saline in areas. and outwash deposits. Ground moraines or till plains cover The Portage Lake lava flows form the bedrock surface large areas of the county and range in thickness from 0 to 300 along the northern shore of Isle Royale and north and north‑ feet. Kames, kame terraces, eskers, and kettles are present west of the Jacobsville sandstone. The Portage Lake Lava in the county and vary greatly in grain size. In some areas, Series consists of basaltic and andesitic lavas interbedded with the till underlies outwash. In moraines and ground moraine conglomerate. Salinity in the water increases with depth in wells, a layer of clay is usually penetrated before the deeper the Portage Lake lava flow (Doonan and others, 1970). The sand and gravel. These wells usually yield enough water for Portage Lake Volcanics form the bedrock surface at Win‑ domestic use. Occasionally, the water may be high in iron. digo, located in Isle Royale National Park. Bailing tests were Outwash occurs in a small portion of the county. These are performed on two bedrock test wells in this area and yielded predominantly sand and gravel deposits. Lacustrine deposits 0.1 and 0.5 gal/min. A pumping test was also performed on are composed of layers of clay, sand, silt, and gravel. Lacus‑ another bedrock test well, which had a yield near 1 gal/min. trine deposits in the Keweenaw County are predominantly These wells were abandoned and grouted. Wells in the Portage sand. Wells in sandy lacustrine deposits may also tap sand and Lake Volcanics at Windigo did not yield sufficient amounts of gravel outwash deposits below the lacustrine deposits. Lacus‑ water (Grannemann and Twenter, 1982). trine wells may provide moderately hard water that may have high iron content (Doonan and others, 1970). According to the Public Water Supply database, the estimated transmissivity for Lake County glacial wells ranges from approximately 1,440 to 1,800 ft2/day. Water from the glacial aquifer may be high in iron content and Lake County is in the western north‑central Lower Pen‑ is not saline (Doonan and others, 1970). insula of Michigan. The Pere Marquette‑White, Muskegon, The bedrock aquifer provides a large portion of the and Manistee watersheds drain the county. According to the ground‑water supply in Keweenaw County. Using the specific February 2005 Wellogic database, approximately 98 percent of 40 Summary of Hydrogeologic Conditions by County for the State of Michigan the wells in Lake County are completed in the glacial depos‑ clay and silt. In the Belle River basin, approximately 75 ft of its, and 0 percent in the bedrock units. There is insufficient clay overlie glacial sand and gravel deposits (Twenter, 1975). information to make this distinction for 2 percent of the wells According to the Public Water Supply database, the estimated in the county. transmissivity for glacial wells ranges from approximately 425 In the Michigan Basin, the glacial aquifer consists of sand to 10,285 ft2/day. Water from the glacial deposits may be hard and gravel that is part of a thick sequence of Pleistocene gla‑ and have a high concentration of dissolved solids in the Belle cial deposits. With the available information, glacial litholo‑ River basin (Twenter, 1975). Arsenic concentrations in Lapeer gies cannot be regionally correlated in the subsurface. This is County exceed the 2006 USEPA maximum contaminant level likely due to the lateral and vertical heterogeneity of glacial of 10 µg/L in some wells (Haack and Rachol, 2000d). deposits that resulted from a complex depositional history The Michigan Formation, Marshall Sandstone, and Cold‑ (Westjohn and others, 1994). In Lake County, glacial deposits water Shale form the bedrock surface in Lapeer County. The are 201 to 1,000 ft thick. The thickness of the deposits gener‑ Michigan Formation consists of layers of sandstone, siltstone, ally increases to the northeast in the county (Western Michigan anhydrite or gypsum, dolomite, limestone, and shale. The University, 1981). Glacial deposits in Lake County consist of lower permeability lithologies of the Michigan Formation are primarily outwash and till. Outwash is interspersed through‑ generally considered a confining unit within the State (West‑ out the county and composed of primarily sand and gravel. john and Weaver, 1998). Locally, the Michigan Formation Coarse‑grained till in moraines and till plains are located can supply small quantities of water. According to the Public sporadically throughout the county, and cover the southeastern Water Supply database a well completed in the Michigan and southwestern corners of the county (Farrand and Bell, Formation has an estimated transmissivity of approximately 1982). According to the Public Water Supply database, the 985 ft2/day. estimated transmissivity for glacial wells ranges from approxi‑ The Marshall Sandstone underlies the Michigan Forma‑ mately 1,960 to 21,270 ft2/day. Bedrock underlies the glacial tion. The Marshall Sandstone consists of one or more strati‑ deposits, but is not currently used for ground‑water supplies. graphically continuous permeable sandstones. The upper sandstone is a quartzarenite to sublitharenite that is referred to as the Napoleon Sandstone Member. A shale, siltstone, and/or Lapeer County carbonate layer separates the Napoleon Sandstone Member from the underlying lower Marshall sandstone. The lower Lapeer County is in the eastern south‑central Lower Marshall sandstone is comprised of two units. The upper unit Peninsula of Michigan. The Flint, Cass, St. Clair, and Clinton is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ watersheds cross Lapeer County in the western, northeastern, enite to sublitharenite. At the base of the Marshall Sandstone eastern, and southeastern portions, respectively. According is a fine‑ to medium‑grained litharenite that ranges in thick‑ to the February 2005 Wellogic database, approximately 23 ness from 30 to 125 ft. Permeable sandstones in the Marshall percent of the wells in Lapeer County are completed in the Sandstone comprise the Marshall aquifer. The Marshall glacial deposits, and 72 percent in the bedrock units. There is aquifer ranges in thickness from 75 to greater than 200 ft insufficient information to make this distinction for 5 percent within the State (Westjohn and Weaver, 1998). According to of the wells in the county. the Public Water Supply database, the estimated transmissivity The Belle River and Black River basins are part of the St. for a well completed in the Marshall aquifer is approximately Clair watershed. Soils in the northwestern portion of the Belle 4,345 ft2/day. The Marshall aquifer yields fresh water in Lap‑ River basin consist of sand, loamy sand, sandy loam, silt loam, eer County (Westjohn and Weaver, 1996c). Haack and Rachol limy loam, clay, muck, and peat. The southwestern portion of (2000d) found the highest arsenic concentrations in Lapeer the Black River basin is located in Lapeer County. Soils in the County in bedrock wells tapping the Michigan Formation and Black River basin consist of poorly drained, silt, loam, and the Marshall Sandstone. clay loam (Twenter, 1975). The Coldwater Shale consists of shale, sandstone, silt‑ In the Michigan Basin, glacial aquifers consist of sand stone, and carbonates. This is considered to be a confining unit and gravel that are part of a thick sequence of Pleistocene and from east to west across the State, is from 500 to 1,300 ft glacial deposits. With the available information, glacial thick. More sandstone beds are present in the Coldwater Shale lithologies cannot be regionally correlated in the subsurface. in the eastern part of the State; however, the Coldwater Shale This is likely due to the lateral and vertical heterogeneity of does not contribute a significant amount of ground water to the glacial deposits that resulted from a complex depositional region (Westjohn and Weaver, 1998). However, bedrock wells history (Westjohn and others, 1994). The thickness of glacial in the Black River basin obtain water from the sandstone in deposits in Lapeer County ranges from 11 to 400 ft (West‑ the Coldwater Shale. Underlying the Coldwater Shale is the ern Michigan University, 1981). The county is composed of Sunbury Shale, which is another predominantly shale layer outwash, till, and lacustrine deposits (Farrand and Bell, 1982). (Twenter, 1975). Sunbury Shale is not considered an aquifer in Outwash is primarily sand and gravel. Till occurs in moraine the county. and till plains, and is fine to coarse grained (Farrand and Bell, Berea Sandstone underlies the Sunbury Shale. The Berea 1982). Lacustrine deposits are predominately composed of Sandstone consists of shale and fine‑grained, well‑sorted sand‑ County Summaries 1 stone. In the northwestern portion of the Belle River basin, The surficial deposits on North Fox Island include several wells obtain water from the Berea Sandstone (Twenter, coarse‑grained lacustrine deposits along the shoreline, and 1975). dune sand in the central portion of the island. South Fox Island is composed of dune sand along most of the shoreline, coarse‑grained lacustrine deposits in the southeastern portion, Leelanau County and coarse‑grained till in the central and eastern portions of the island (Farrand and Bell, 1982). Glacial deposits are gener‑ Leelanau County is in the northwestern portion of ally heterogeneous in the subsurface. Some of the most promi‑ the Lower Peninsula of Michigan. A portion of Sleeping nent features in Leelanau County are the dune‑sand deposits Bear Dunes National Lakeshore is located in the county, which occur along the Lake Michigan shoreline. which includes North and South Manitou Island. North and A portion of Sleeping Bear Dunes National Lakeshore South Fox Island are also included in Leelanau County. The is located along the southwestern edge of the county and the Betsie‑Platte, Boardman‑Charlevoix, and Lake Michigan glacial deposits are from 500 to 700 ft thick. In the park, the watersheds drain the county. According to the February 2005 values for specific capacity range between less than 1 and 50 Wellogic database, approximately 94 percent of the wells in gal/min/ft for glacial wells (Handy and Stark, 1984). Handy Leelanau County are completed in the glacial deposits, and and Stark (1984) have identified areas of high specific capac‑ 1 percent in the bedrock units. There is insufficient informa‑ ity in glacial wells at and near Sleeping Bear Dunes National tion to make this distinction for 5 percent of the wells in the Lakeshore. These occur north and northeast of Lime Lake, county. The majority of the bedrock wells are in the northern east of Empire, west of Armstrong Lake, southeast of Glen tip of the Leelanau Peninsula. Lake, and northeast of Glen Arbor (Handy and Stark, 1984, p. With the available information, glacial lithologies cannot 23). The ground water in Sleeping Bear Dunes National Lake‑ be regionally correlated in the subsurface. This is likely due shore is generally of good quality, although in some areas, the to the lateral and vertical heterogeneity of glacial deposits that chloride and sulfate levels are high. resulted from a complex depositional history. In the Michigan The surficial deposits on North Manitou Island include Basin, the glacial aquifer consists of sand and gravel that is coarse‑grained glacial till on most of the island. Areas of part of a thick sequence of Pleistocene glacial deposits (West‑ coarse‑grained lacustrine deposits are present on the northern john and others, 1994). The glacial deposits in the county and eastern parts of the island. Areas along the shoreline of range from 201 to 1,000 ft in thickness. However, the major‑ North Manitou Island are covered in dune sand. The shoreline ity of the glacial deposits in the county are between 401 and of South Manitou Island is composed of dune sand, except in 800 ft thick (Western Michigan University, 1981). The glacial the southern portion. Coarse‑grained till forms the southern deposits in the county include outwash, lacustrine deposits, and central surface of the island (Farrand and Bell, 1982). and till. Outwash is present in the southern portion of the Ground water supplies on North Manitou Island are generally county, and is composed of permeable sand and gravel. Till is hard and may be hard in some areas on South Manitou Island. coarse grained, and is present in both till plains and moraines. An unusual dissolved phosphorous concentration was found in According to the Public Water Supply database, the estimated a well on South Manitou Island (Handy and Stark, 1984). transmissivity for glacial till in Leelanau County is 17,856 From southeast to northwest, the bedrock surface of ft2/day. Leelanau County is composed of the Ellsworth Shale, Antrim The thickness of the glacial till on the Leelanau Peninsula Shale, Traverse Group, and Detroit River Group which all is between 50 and greater than 150 ft, increasing southward. underlie the glacial deposits. The Ellsworth Shale is composed Both a portion of the Manistee Moraine and till plains with of a gray to greenish‑gray shale. Ellsworth Shale generally drumlins comprises the Leelanau Peninsula. The Manistee contains some dolomite and may also be composed of sand‑ Moraine is composed of till, primarily of sand and stones that stone and siltstone layers (Matthews, 1993). The Ellsworth originated from carbonate rock. The till plains have a similar Shale is not considered an aquifer. composition to the Manistee Moraine, except the till plains The Antrim Shale is composed of primarily carbona‑ have a higher clay content. In both the Manistee Moraine and ceous, black to dark‑gray shale. Near the base of the sequence, the till plains, local outwash deposits occur on the Leelanau thin layers of gray shale and limestone may occur. The major Peninsula. The lacustrine deposits in the county are generally constituents in the Antrim Shale consist of quartz, illite, and coarse‑grained. However some lacustrine clays are located in kerogen. Kaolinite, chlorite, and pyrite also compose the Ant‑ areas bordering lakes. Clay lenses also occur in the subsurface rim Shale. The Antrim Shale has been found to have bitumi‑ within the Leelanau Peninsula. The glacial aquifer is gener‑ nous limestone concretions up to 3 ft in diameter (Matthews, ally unconfined in the Leelanau Peninsula. However, where 1993). The Antrim Shale can be up to 656 ft thick, which clay‑rich till occurs, the aquifer may be semi‑confined. Along occurs at the center of the Michigan Basin (Gutschick and the Lake Leelanau and Sutton’s Bay shorelines, flowing wells Sandberg, 1991). The Antrim Shale is generally not consid‑ are present, which are indicative of confined conditions. Large ered an aquifer. capacity wells in the area yield up to 500 gal/min (Regalbuto, The Traverse Group underlies the Antrim Shale in the 1987). county. The majority of the bedrock wells in the county occur  Summary of Hydrogeologic Conditions by County for the State of Michigan where the Traverse Group forms the bedrock surface. Several deposits are thicker than 213 ft. (Caetta, 1991). Glacial depos‑ of these wells are located in the northern tip of the Leelanau its in Lenawee County consist of outwash, till, and lacustrine Peninsula. The Traverse Group primarily consists of fossilif‑ deposits. Glacial outwash is common in the northwestern erous limestone. In some areas the Traverse Group has been portion of Lenawee County and in an area in the center of the highly fractured which leads to local areas of very high perme‑ county (Twenter, 1975; Farrand and Bell, 1982). Outwash ability within that unit. In the western portion of the basin, is predominately sand and gravel deposits. According to the porous dolomite and anhydrite may be present. In the eastern Public Water Supply database, the estimated transmissivity portion of the basin, interlayers of shale are common (Gardner, for glacial wells completed in outwash ranges from approxi‑ 1974). The basal formation of the Traverse Group is the Bell mately 110 to 20,735 ft2/day. Glacial deposits in the central Shale. Bell Shale has a maximum thickness of 80 ft (Cataco‑ portion of the county are primarily till (Twenter, 1975). Till sinos and others, 2001). deposits range from fine to coarse grained (Farrand and Bell, The Detroit River Group forms the Bedrock surface 1982). The eastern and southeastern portions of the county are of both North and South Fox Island. In the subsurface, the composed of glacial‑lacustrine deposits. In the areas where Detroit River Group consists of the Lucas Formation, Amher‑ glacial‑lacustrine deposits are present, well yields are less than stburg Formation, and Sylvania Sandstone. The Lucas Forma‑ 10 gal/min (Knutilla and Allen, 1975; Twenter and others, tion is primarily composed of interlayered carbonates and 1975). These areas contain deposits of clay and silt, with local evaporites. Carbonate‑cemented, fine‑ to medium‑grained, areas of sand and gravel. (Farrand and Bell, 1982). According sandstone lenses are scattered near the basal portion of the to the Public Water Supply database, the estimated transmis‑ formation, sandy in northwestern. The Lucas Formation is up sivity for glacial wells completed in fine‑grained lacustrine to 1,050 ft in thickness in the Michigan Basin. In some areas, deposits ranges from approximately 165 to 1,465 ft2/day. In the water from this formation is brine and may contain hydro‑ the north‑central portion of the county, well yields range from gen sulfide. The Amherstburg Formation underlies the Lucas 10 to 20 gal/min, and from 100 to 1,000 gal/min in some parts Formation. The Amherstburg Formation is up to 300 ft thick (Knutilla and Allen, 1975; Twenter and others, 1975). Glacial and is composed of fossiliferous limestone that is dolomitized wells in the southeastern portion of the county may yield min‑ in some areas. An upper sandstone is present in the formation eralized or saline water (Twenter, 1975; Caetta, 1991). in the western portion of the basin. The Sylvania Sandstone Bedrock underlies the glacial deposits. The bedrock underlies the Amherstburg Formation. The Sylvania Sandstone surface is comprised of, from youngest to oldest, the Marshall is composed of fine‑ to medium‑grained sandstone with quartz Sandstone, Coldwater Shale, Sunbury Shale, Berea Sandstone, overgrowths interlayered with carbonate. Sylvania Sandstone Bedford Shale, Antrim Shale, Traverse Group, Dundee Lime‑ has been eroded in areas of the basin (Gardner, 1974). stone, and Detroit River Group. (Knutilla and Allen, 1975; Twenter, 1975; Twenter and others, 1975; Milstein, 1987). The bedrock‑well yields range from less than 10 to 30 gal/min Lenawee County (Knutilla and Allen, 1975; Twenter and others, 1975). The Marshall Sandstone is present in the northwest por‑ Lenawee County is in the southeastern portion of the tion of the county. The Marshall Sandstone consists of one Lower Peninsula of Michigan. The Black‑Rocky, Tiffin, and or more stratigraphically continuous permeable sandstones. Raisin watersheds drain the county in the central and south‑ The upper sandstone is a quartzarenite to sublitharenite that western, north and central, and southeastern portions of the is referred to as the Napoleon Sandstone Member. A shale, county, respectively. The River Raisin basin covers most of siltstone, and/or carbonate layer separates the Napoleon Sand‑ Lenawee County and the soils in this area consist of sand, stone Member from the underlying lower Marshall sandstone. sandy loam, silt loam, clay loam, limy, loam, and clay (Twen‑ The lower Marshall sandstone is comprised of two units. The ter, 1975). According to the February 2005 Wellogic database, upper unit is generally 50 to 125 ft of fine‑ to medium‑grained approximately 89 percent of the wells in Lenawee County are quartzarenite to sublitharenite. At the base of the Marshall completed in the glacial deposits, and 9 percent in the bedrock Sandstone is a fine‑ to medium‑grained litharenite that ranges units. There is insufficient information to make this distinc‑ in thickness from 30 to 125 ft. Permeable sandstones in the tion for 2 percent of the wells in the county. The majority of Marshall Sandstone comprise the Marshall aquifer. The Mar‑ the wells in the central portion of the county are completed in shall aquifer ranges in thickness from 75 to greater than 200 ft glacial deposits, while bedrock wells are more common in the within the State. Transmissivity values from wells tapping the northeastern and southwestern portions of the county. Marshall aquifer in nearby Jackson County are between 7,500 In the Michigan Basin, glacial aquifers consist of sand and 29,000 ft2/day (Westjohn and Weaver, 1998). The Mar‑ and gravel that are part of a thick sequence of Pleistocene gla‑ shall aquifer yields fresh water in Lenawee County (Westjohn cial deposits. With the available information, glacial litholo‑ and Weaver, 1996c). gies cannot be regionally correlated in the subsurface. This is The Coldwater Shale underlies the Marshall Sandstone likely due to the lateral and vertical heterogeneity of glacial and forms the majority of the bedrock surface in Lenawee deposits that resulted from a complex depositional history County. The Coldwater Shale is composed primarily of shale (Westjohn and others, 1994). In areas of the county, the glacial and also includes carbonate, siltstone, and sandstone. In the County Summaries  western portion of the State, the Coldwater Shale contains County soils are generally poorly drained and predominantly more carbonate than siltstone or sandstone, and in the eastern composed of clays. However, in the east and southeastern portion of the State more sandstone beds are present in the portion of the county, there are localized areas of sandy soils Coldwater Shale (Monnett, 1948). In most of the State, the that allow rapid drainage (Livingston County Planning Depart‑ impermeable lithologies in the Coldwater Shale comprise the ment, 1993). The soils in the Huron River basin, in the south‑ Coldwater confining unit (Westjohn and Weaver, 1998). ern portion of the county, are sand, sandy loam, silt loam, clay The Sunbury Shale underlies the Coldwater Shale. The loam, clay, and limy loam (Twenter, 1975). According to the Sunbury Shale is slightly calcareous with areas of pyrite. In February 2005 Wellogic database, approximately 80 percent nearby counties, the Sunbury Shale yields little, if any, water of the wells in Livingston County are completed in the glacial and is mineralized with depth. The Berea Sandstone underlies deposits, and 17 percent in the bedrock units. There is insuf‑ the Sunbury Shale. In general, the Berea Sandstone consists ficient information to make this distinction for 3 percent of the of two to three sandstones separated by shale. The upper wells in the county. This is similar to the 1993 estimate from unit is a fine‑grained, cemented silty and/or shaly, dolomitic the Livingston County Planning Department, who found that sandstone that contains micas and pyrite in areas. The middle approximately 81 percent of the wells in the county tap glacial unit is more friable and consists of fine to medium sandstone deposits. Bedrock wells are more common on the western side with beds of shale and well‑cemented sandstone. The lower of the county. unit is a fine‑grained, cemented silty and/ or shaly, dolomitic In the Michigan Basin, glacial aquifers consist of sand sandstone that contains micas and pyrite in areas, but contains and gravel that are part of a thick sequence of Pleistocene less pyrite and more shale (Ferris and others, 1954). Saline glacial deposits. With the available information, glacial water has been recorded in wells tapping the Berea Sandstone lithologies cannot be regionally correlated in the subsurface. in nearby Oakland County at 1,000 ft in depth (Mozola, 1954). This is likely due to the lateral and vertical heterogeneity of The Bedford Shale underlies the Berea Sandstone. In general, glacial deposits that resulted from a complex depositional the Bedford Shale consists of shale, sandy shale, and shaly history (Westjohn and others, 1994). Glacial deposits in Liv‑ limestone (Ferris and others, 1954). The Bedford Shale does ingston County are less than 100 ft thick in the west (Vanlier, not yield much, if any, water to wells in counties located near 1968) and thicken to 400 ft in the east (Twenter, 1975). Till Lenawee. and outwash are the dominant types of glacial deposits in the The Antrim Shale underlies the Bedford Shale. In county (Vanlier, 1968; Twenter, 1975). Both moraines and till general, the Antrim Shale is composed of shale with concre‑ plains are composed of till, a compilation of clay, silt, sand, tions of pyrite and possibly anthraconite and marcasite are gravel, and boulders, and both may contain lenses of out‑ present in the Antrim Shale (Ferris and others, 1954; Nicho‑ wash. The majority of the till in Livingston County is medium las and others, 1996). The Traverse Group underlies Ant‑ grained (Livingston County Planning Department, 1993). rim Shale. Pyrite is present throughout the Traverse Group, According to the Public Water Supply database, the estimated which consists of beds of shale, limestone, and dolomite. The transmissivity for wells completed in medium‑textured till Dundee Limestone underlies the Traverse Group. Interbed‑ ranges from approximately 950 to 9,640 ft2/day. Outwash is ded limestone and dolomite compose the Dundee Limestone. composed of sand and gravel. The presence and thickness of The limestone contains small vugs and the dolomite contains outwash declines in the southwestern and western portions of vugs and fractures. Celestite and calcite are minerals that are the county (Vanlier, 1968; Twenter, 1975). According to the present in the vugs. Sulfur was found to occur in the fractures Public Water Supply database, the estimated transmissivity for at shallow depths in areas of nearby Monroe County (Nicholas wells completed in outwash ranges from approximately 3,350 and others, 1996). to 213,552 ft2/day. Water from glacial deposits is hard and The Detroit River Group underlies the Dundee Lime‑ contains some iron (Twenter, 1975). stone. In nearby Monroe County, high concentrations of Bedrock underlies the glacial deposits in the county. The hydrogen sulfide were found in water from wells where the crests of the Freedom Anticline and Howell Anticline run Dundee Limestone and the Detroit River Group formed the through Livingston County. The bedrock surface includes the bedrock surface (Nicholas and others, 1996). Gas is found in Saginaw Formation, Bayport Limestone, Michigan Formation, the Detroit River Group in Washtenaw County. Also, in Mon‑ Marshall Sandstone, Coldwater Shale, Sunbury Shale, Berea roe and Washtenaw County, the Detroit River Group yields Sandstone, and Bedford Shale (Milstein, 1987). water for domestic supplies (Fleck, 1980). In Livingston County, the Saginaw aquifer yields fresh water (Westjohn and Weaver, 1996c). The Saginaw Forma‑ tion contains interbeds of sandstone, siltstone, limestone, coal, Livingston County and shale (Westjohn and Weaver, 1998). The Saginaw aquifer is the permeable sandstones from the Saginaw Formation. Livingston County is in the southeastern Lower Peninsula The Saginaw aquifer ranges in thickness from less than 100 of Michigan. The Huron, Shiawassee, and the Upper Grand to 370 ft within the State (Westjohn and Weaver, 1996a). The watersheds drain the county in the southern, north‑central, Saginaw confining unit underlies the Saginaw aquifer. The and western portions of the county, respectively. Livingston Saginaw confining unit is approximately 50 ft thick in the  Summary of Hydrogeologic Conditions by County for the State of Michigan county. It is primarily shale, with thin layers of discontinuous Underlying the Marshall Sandstone is the Coldwater sandstone, siltstone, limestone, and coal. The permeable layers Shale. The Coldwater Shale consists of shale, sandstone, within the Saginaw confining unit appear to be isolated from siltstone, and carbonates. It is generally considered a confin‑ the regional ground‑water‑flow system (Westjohn and Weaver, ing unit and ranges in thickness, from east to west across the 1996a). state, from 500 to 1,300 ft (Westjohn and Weaver, 1996b). The Saginaw confining unit separates the Saginaw aqui‑ More sandstone beds are present in the Coldwater Shale in the fer from the underlying Parma‑Bayport aquifer. The Parma eastern part of the state (Monnett, 1948). In areas of Livings‑ Sandstone is often considered the basal unit of the Saginaw ton County, sandstone units within the Coldwater Shale yield Formation, although the stratigraphic relationship is not small water supplies (Twenter, 1975). clear between the Saginaw Formation, Parma Sandstone, and The Sunbury Shale, Berea Sandstone, and Bedford Shale Mississippian‑aged Bayport Limestone. The Parma Sandstone subcrop in the southeastern corner of the county. Sunbury is composed of medium‑ to coarse‑grained sandstone, and Shale underlies Coldwater Shale. Sunbury Shale is generally is generally less than 100 ft thick (Cohee and others, 1951). slightly calcareous shale with areas of pyrite. Sunbury Shale The Bayport Limestone is a fossiliferous, cherty limestone, yields little if any water that is mineralized with depth. The often with interbedded sandstone and varies considerably in Berea Sandstone underlies the Sunbury Shale. In general, the thickness from one area to another. The Bayport Limestone Berea Sandstone consists of two to three sandstones separated and Parma Sandstone appear to interfinger throughout the by shale. The upper unit is a fine‑grained, cemented silty and/ Michigan Basin. These units are hydraulically connected, or shaly, dolomitic sandstone that contains micas and pyrite in and together they form the Parma‑Bayport aquifer. The areas. The middle unit is more friable and consists of fine to Parma‑Bayport aquifer is approximately 100 to 150 ft thick medium sandstone with beds of shale and well‑cemented sand‑ within the Michigan Basin (Westjohn and Weaver, 1996a). stone. The lower unit is a fine‑grained, cemented silty and/or Please note that due to the uncertainty of stratigraphic relation‑ shaly, dolomitic sandstone that contains micas and pyrite in ship between these units, in other reports this aquifer may be areas, but contains less pyrite and more shale (Ferris and oth‑ delineated differently. The Parma‑Bayport aquifer may yield ers, 1954). In areas of the State, water from the Berea Sand‑ saline water in Livingston County (Westjohn and Weaver, stone may be saline or of good quality (Mozola, 1954). The 1996c). Bedford Shale underlies the Berea Sandstone, and consists The Michigan Formation underlies the Bayport Lime‑ of shale, sandy shale, and shaly limestone (Ferris and others, stone. The Michigan Formation consists of layers of sand‑ 1954). The Bedford is not considered an aquifer in the county. stone, siltstone, anhydrite or gypsum, dolomite, limestone, and shale. The lower permeability lithologies of the Michigan Formation are generally considered a confining unit that Luce County separates the Parma‑Bayport aquifer from the underlying Luce County is in the eastern portion of the Upper Pen‑ Marshall aquifer. The thickness of the Michigan confining unit insula of Michigan. The Betsy‑Chocolay, Tahquamenon, Lake ranges from less than 50 to 400 ft within the State (Westjohn Superior, Manistique, and Brevoort‑Millecoquins watersheds and Weaver, 1998). Locally, however, the Michigan Formation drain the county. According to the February 2005 Wellogic may supply small supplies of water in the county. database, approximately 88 percent of the wells in Luce The Marshall Sandstone underlies the Michigan Forma‑ County are completed in the glacial deposits, and 10 percent tion. The Marshall Sandstone consists of one or more strati‑ in the bedrock units. There is insufficient information to make graphically continuous permeable sandstones. The upper this distinction for 2 percent of the wells in the county. The sandstone is a quartzarenite to sublitharenite that is referred to glacial aquifer is the source of ground water for most of the as the Napoleon Sandstone Member. A shale, siltstone, and/or wells; however, bedrock aquifers are used in areas where the carbonate layer separates the Napoleon Sandstone Member glacial deposits are thin and/or have low permeability. Bed‑ from the underlying lower Marshall sandstone. The lower rock wells are located in various places in the county, but the Marshall sandstone is comprised of two units. The upper unit majority are found in two clusters in the southern portion of is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ the county. enite to sublitharenite. At the base of the Marshall Sandstone Aquifers in the glacial deposits consist largely of sands is a fine‑ to medium‑grained litharenite that ranges in thick‑ and gravels and vary regionally in thickness and permeabil‑ ness from 30 to 125 ft. Permeable sandstones in the Marshall ity. In Luce County, the glacial deposits are composed of till, Sandstone comprise the Marshall aquifer. The Marshall aqui‑ outwash, lacustrine sediments, and dunes. The outwash plain, fer ranges in thickness from 75 to greater than 200 ft within located just southeast of the center of the county is composed the State (Westjohn and Weaver, 1998). According to the of sand and gravel. Three morainic systems are present. The Public Water Supply database, the estimated transmissivity for Newberry Moraine is in the southern portion of the county, Marshall aquifer ranges from approximately 2,533 to 31,680 and composed primarily of sandy till, with areas of sand and ft2/day. The Marshall aquifer yields both saline and fresh water gravel outwash. The Munising Moraine and the Crisp Point in Livingston County (Westjohn and Weaver, 1996c) Moraine are located in the central and northern portion of the County Summaries  county, respectively. These moraines are both primarily sand, is generally good. The Prairie du Chien Group and the Munis‑ with some lenses of coarser sand and gravel. Lacustrine depos‑ ing Formation are sometimes used in the southern part of the its rich in clay may separate the glacial aquifer into layers that county when the water quality of the overlying units is poor. are confined or semi‑confined. The glacial deposits range in The Jacobsville Sandstone underlies the Munising thickness from 0 to 320 ft, and generally thin from south to Formation when the Munising Formation is present. In the north in the county. The average transmissivity for the glacial northernmost portion of Luce County, the Jacobsville Sand‑ aquifer ranges between 145 to 9,820 ft2/day. This estimate is stone directly underlies the glacial deposits. The Jacobsville based on the specific capacity values from Vanlier (1959). Sandstone is a jointed, silica‑cemented sandstone. In nearby The bedrock underlies the glacial deposits throughout counties, the permeability of the Jacobsville Sandstone Luce County. The bedrock units in the county dip to the decreases with depth (Vanlier, 1959). south, toward the center of the Michigan Basin. As a result, bedrock units in the county thin to the north. In the southern part of Luce County, the younger bedrock units are present. Mackinac County Limestone and dolomite from the Burnt Bluff Group form the Mackinac County is in the southeast portion of the Upper bedrock surface in a very small area in the southeast portion of Peninsula of Michigan. The Tahquamenon, Manistique, the county. In this area, the Burnt Bluff Group supplies water Brevoort‑Millecoquins, Lake Michigan, St. Marys, Carp‑Pine, to wells. The Burnt Bluff Group is mainly dolomite and shale and Lake Huron watersheds drain the county. According to the with areas of gypsum. The Cataract Formation underlies the February 2005 Wellogic database, approximately 24 percent Burnt Bluff Group and subcrops in the southern portion of of the wells in Mackinac County are completed in the glacial Luce County. Layers of gypsum are present in the Cataract deposits, and 68 percent in the bedrock units. There is insuf‑ Formation, which is predominately composed of dolomite and ficient information to make this distinction for 8 percent of the shale. The estimated transmissivity, of the Cataract Formation wells in the county. is 230 ft2/day, which was calculated from specific capacity Aquifers in the glacial deposits consist largely of sands values (Vanlier, 1959). Water in the Cataract Formation tends and gravels and vary regionally in thickness and permeability. to be of poor quality. The glacial deposits in Mackinac County range in thickness Below this, lies the upper portion of the Richmond from 0 to 300 feet. In some areas the glacial drift is discon‑ Group. The upper portion of the Richmond Group is com‑ tinuous and/or thin. Glacial deposits are thickest in a bedrock posed of limestone and dolomite interbedded with shale. Shaly valley that extends from St. Martin Bay, on Lake Huron, to and sandy dolomite is also present in the group. In Schoolcraft Whitefish Bay, on Lake Superior. Glacial deposits consist of County, gypsum is found in the upper portion of the Rich‑ till in moraines and till plains, outwash, lacustrine deposits, mond Group and this may also be true for Luce County. Water dune sand, and beach deposits. The stratified deposits (out‑ from the Richmond Group may be confined and the estimated wash, lacustrine, dune, beach and beach deposits) tend to be transmissivity is 110 ft2/day. Estimated transmissivity values more permeable and yield more water to wells than unstrati‑ are calculated from the specific capacity values (Vanlier, 1959; fied deposits (glacial till). In Mackinac County it is difficult to Vanlier and Deutsch, 1958a). Water from the upper portion map the unstratified deposits because many of them have been of the Richmond Group can be of good quality in some areas eroded and covered by lacustrine deposits. Both water‑laid (45N 11W) while it is poor quality in other areas (45N 10W) and land‑laid moraines are present in Mackinac County. They of Luce County. are composed of stratified and unstratified till, respectively. Below this, lies an impermeable layer of shale from the In both types of moraines, the degree of sorting varies. In Richmond Group and , which combined is general, in the east of the county, moraines are composed up to 200 ft thick. Underlying the Collingwood Shale is the of clayey till that is a poor source of water. However, where Trenton and Black River Formation. The Trenton and Black lenses of sand and gravel are present in the clayey till, small River Formations are composed of limestone, dolomite, and amounts of water may be obtained. The moraines on the west‑ dolomitic shale. The base of the Black River Formation is a ern side are composed of sand and yield a moderate amount of shale layer. Wells in the Trenton and Black River Formations water. Till plains may supply a small amount of water to local have supplied both fresh and saline water in nearby counties. shallow wells because these deposits are thin and discontinu‑ Underlying the Black River Formation is the Prairie ous over the surface of Mackinac County. Small to moderate du Chien Group and underlying Munising Formation (Van‑ yields of water come from outwash deposits. These deposits lier, 1959). According to Vanlier (1959), these form a single often occur near moraines, and are predominately composed of confined aquifer. The Prairie du Chien Group, referred to as sand in Mackinac County. Clayey glacial lake‑plain deposits the Hermansville Formation by Vanlier (1959), is composed of act as confining layers where present. Small amounts of water sandstone, dolomitic sandstone, and dolomite. The Munising come from sandy glacial lake‑plain deposits. Small to moder‑ Formation underlies the Prairie du Chien Group. The Munis‑ ate supplies of ground water may come from dune sand and ing Formation is composed of fine to medium‑grained sand‑ beach deposits. Dune sand and beach deposits provide areas of stone, and may have a conglomerate layer at the base. Water recharge to ground water (Vanlier and Deutsch, 1958b). quality in the Prairie du Chien Group and Munising Formation  Summary of Hydrogeologic Conditions by County for the State of Michigan

Bedrock underlies the glacial deposits of Mackinac mations. Munising Sandstone underlies the Prairie du Chien County. In general, the bedrock dips south in Mackinac Group. The basal shale of the Black River Formation may County. The youngest bedrock consists of the Bois Blanc confine the Prairie du Chien Group and the Munising Sand‑ Formation, St. Ignace Formation, , and stone (Vanlier, 1959). The Prairie du Chien Group is similar Mackinac Breccia. The Bois Blanc Formation and the St. to Munising Sandstone in composition, but contains larger Ignace Formation may be possible sources for ground water amounts of dolomite. Munising Sandstone is composed of fine on Bois Blanc Island. Cherty dolomite and limestone make up to medium‑grained sandstone with localized areas of dolomite. the Bois Blanc Formation. The Bois Blanc Formation over‑ Combined, the Prairie du Chien Group and Munising Sand‑ lies the St. Ignace Formation, which is estimated to be 200 to stone are greater than 250 ft thick and produce good quality 250 ft thick. The St. Ignace Formation is primarily dolomite water. underlying Precambrian rocks are not a likely source of and shale. The Salina Formation ranges from 500 to 600 ft water in Mackinac County (Valier and Deutsch, 1958b). thick and consists of shale, limestone, dolomite, gypsum, and some remaining layers of salt. The permeability of the Salina Formation varies and the water in the Salina Formation may Macomb County be of poor quality. Ground‑water percolation led to leaching Macomb County is in the southeastern portion of the of the salt in the Salina Formation, which formed void space, Lower Peninsula of Michigan. St. Clair, Lake St. Clair, and and caused the Bois Blanc Formation, St. Ignace Formation, Clinton watersheds drain Macomb County in the northeast‑ and Salina Formation to collapse. This created what is referred ern, central eastern, and the central and western portions of to as Mackinac Breccia. Mackinac Breccia is composed of the the county, respectively. In the portion of the Clinton River aggregates of the Bois Blanc Formation, St. Ignace Formation, basin that is located in Macomb County, the soils are poorly and Salina Formation. The Mackinac Breccia is a poor source to well‑drained sand, loamy sand, silty sand, silty loam, clay of ground water because it varies in its degree of permeability loam, limy loam, clay, and loam. According to the February and is generally of poor quality. 2005 Wellogic database, approximately 93 percent of the wells Three quarters of the bedrock surface in Mackinac in Macomb County are completed in the glacial deposits, and County is composed of limestone and dolomite of the Niagara 3 percent in the bedrock units. There is insufficient informa‑ Series. The Niagara Series includes Engadine Dolomite, tion to make this distinction for 4 percent of the wells in the Manistique Dolomite, and the Burnt Bluff Formation. Dissolu‑ county. tion cavities form permeable areas in the Niagara Series, and Aquifers in the glacial deposits consist largely of sands are an important source of water in the county. The permeable and gravels and vary regionally in thickness and permeability. areas are often thin in the Niagara Series, and are separated by With the available information, glacial lithologies cannot be areas of lower permeability that form confining layers within regionally correlated in the subsurface. This is likely due to the unit. The Niagaran Series of rocks serves as the primary the lateral and vertical heterogeneity of glacial deposits that bedrock aquifer for the county. resulted from a complex depositional history (Westjohn and A layer of shale may impede the movement of water others, 1994). Glacial deposits in Macomb County consist of between the Cataract Formation and the overlying Niagara lacustrine, outwash, and till deposits (Nowlin, 1973). Both Series in Mackinac County (Vanlier and Deutsch, 1958b). The fine‑ to coarse‑grained lacustrine deposits are present in the Cataract Formation is a semi‑confined to confined aquifer county (Farrand and Bell, 1982). The Clinton River basin con‑ in Mackinac County and is approximately 210 ft thick. The sists primarily of relatively flat lacustrine and glacial deposits Cataract Formation consists of alternating limestone, dolomite, range in thickness from 100 to 200 ft. Here, lacustrine deposits and shale beds, with areas of gypsum. The Cataract Formation are composed primarily of clay and sand (Twenter, 1975; forms the bedrock surface in the northeastern and northwest‑ Nowlin, 1973). In the northwestern portion of the county, the ern parts of Mackinac County, which allows increased move‑ surficial deposits include outwash, which is composed of sand ment of ground water between the Cataract Formation and and gravel (Farrand and Bell, 1982). Till plains and moraines, overlying glacial deposits. The base of the Cataract Formation consisting of fine to coarse‑grained till, generally trend is shale (Vanlier and Deutsch, 1958a) and may confine the southwest to northeast across the county (Farrand and Bell, underlying upper portion of the Richmond Group in Macki‑ 1982). The Belle River basin is part of the St. Clair watershed nac County. The upper portion of the Richmond Group is and located in the northeastern portion of the county. Here, approximately 160 ft of limestone and dolomite. The base of the glacial deposits range in thickness from 300 ft near the the Richmond Group and the Collingwood Formation form center of Belle River basin to 150 ft. In the central portion an impermeable shale layer that is approximately 240 ft thick. of the Belle River basin, clay hardpan is approximately 75 ft Underlying this is the Trenton Formation and the Black River thick and overlies sand and gravel deposits (Twenter, 1975). Formation. The Trenton and Black River Formations are com‑ According to the Public Water Supply database, the estimated posed of limestone and dolomite with sandy and shaly beds. In transmissivity for glacial wells ranges from approximately 450 the northwest portion of the county, the Trenton Formation and to 26,500 ft2/day. In the Clinton River basin, water from the Black River Formation produce poor quality water. The Prairie du Chien Group underlies the Trenton and Black River For‑ County Summaries  glacial wells is moderately hard and chloride and dissolved Manistee County solid concentrations increase with depth (Twenter, 1975). Bedrock underlies the glacial deposits. The units that Manistee County is in the northwestern portion of the form the bedrock surface of Macomb County, trend south‑ Lower Peninsula of Michigan. The western edge of the county west to northeast, from youngest to oldest. The bedrock in the borders Lake Michigan. Pere Marquette‑White, Manistee, area consists of the Coldwater Shale, Sunbury Shale, Berea Betsie‑Platte, and Lake Michigan watersheds drain the Sandstone, Bedford Shale, and Antrim Shale. Just east of county. According to the February 2005 Wellogic database, Macomb County, in Oakland County, the Coldwater Shale has approximately 98 percent of the wells in Manistee County are sandstone units in areas of the county that may yield sufficient completed in the glacial deposits, and 0 percent in the bedrock supplies of water. In addition, the Berea Sandstone also yields units. There is insufficient information to make this distinction sufficient amounts of water nearby in areas of Oakland County for 2 percent of the wells in the county. (Twenter, 1975). However, water from bedrock in the region In the Michigan Basin, the glacial aquifer generally tends to be mineralized, especially with increasing depth consists of sand and gravel that is part of a thick sequence (Twenter and others, 1975). of Pleistocene glacial deposits. With the available informa‑ The Coldwater Shale forms the bedrock surface in the tion, glacial lithologies cannot be regionally correlated in northern portion of Macomb County (Nowlin, 1973). Coldwa‑ the subsurface. This is likely due to the lateral and vertical ter Shale consists of shale, sandstone, siltstone, and carbon‑ heterogeneity of glacial deposits that resulted from a complex ates. This is generally considered to be a confining unit and depositional history (Westjohn and others, 1994). The glacial ranges in thickness, from east to west across the State, from deposits range from 201 to 1,000 ft thick within Manistee 500 to 1300 ft. More sandstone beds are present in the Cold‑ County (Western Michigan University, 1981). The glacial water Shale in the eastern part of the State (Monnett, 1948) deposits in Manistee County consist of till, lacustrine depos‑ however, the Coldwater Shale does not contribute a significant its, and outwash. Medium‑ to coarse‑grained till is present in amount of ground water to the region (Westjohn and Weaver, the county in moraines and till plains. The medium‑grained 1996b). In nearby Oakland County, Coldwater Shale may till primarily occurs in the western portion of the county. yield freshwater where it is near the surface, but yields miner‑ However, areas of coarse‑grained till occur to the east of this. alized water with depth (Ferris and others, 1954). The Port Huron Moraine occurs in the eastern portion of the The Sunbury Shale, Berea Sandstone, and Bedford Shale county and is composed of coarse‑grained till. Coarse‑grained form the bedrock surface southeast of the Coldwater Shale in lacustrine deposits are present on the surface primarily in the Macomb County. Sunbury Shale underlies Coldwater Shale. central portion of the county and also in areas along the Lake Sunbury Shale is generally slightly calcareous shale with areas Michigan shoreline. Outwash also is abundant in the county of pyrite. Sunbury Shale yields little if any water that is miner‑ and is composed of sand and gravel. Ice‑contact outwash alized with depth. The Berea Sandstone underlies the Sunbury occurs in areas in the southern portion of the county (Farrand Shale. The Berea Sandstone consists of two to three sand‑ and Bell, 1982). The Udell Hills are located in south‑central stones separated by shale. The upper unit is a fine‑grained, Manistee County, and rise to a maximum of 300 ft above the cemented silty and/ or shaly, dolomitic sandstone that contains surrounding level sand plains. The glacial deposits in the area micas and pyrite in areas. The middle unit is more friable and are approximately 500 ft thick. The Udell Hills are composed consists of fine to medium sandstone with beds of shale and primarily of sand. However, local gravel and boulder beds and well‑cemented sandstone. The lower unit is a fine‑grained, clay lenses randomly occur within the hills (Kellogg, 1964). cemented silty and/ or shaly, dolomitic sandstone that contains Sand dunes composed of fine‑ to medium‑grained sand occur micas and pyrite in areas, but contains less pyrite and more along the Lake Michigan shoreline. According to the Public shale (Ferris and others, 1954). Water Supply database, based on aquifer tests the estimated In the region where the Berea Sandstone forms the bed‑ transmissivity for glacial wells in the county ranges from rock surface, yields from these wells are generally adequate approximately 990 to 37,400 ft2/day. Bedrock underlies the for domestic use (Twenter and others, 1975). However, saline glacial deposits, but is not currently used for water supply. water has been recorded in wells tapping Berea Sandstone nearby in Oakland County, near 1,000 ft in depth (Mozola, 1954). The Bedford Shale underlies the Berea Sandstone. Marquette County The Bedford Shale consists of shale, sandy shale, and shaly Marquette County is in the north‑central portion of the limestone. The Antrim Shale underlies Bedford Shale. The Upper Peninsula of Michigan. The Dead‑Kelsey, Betsy‑Choc‑ Antrim Shale is composed of shale with concretions of pyrite olay, Lake Superior, Michigamme, Cedar‑Ford, Escanaba, and anthraconite. The Antrim Shale yields small water sup‑ and Tacoosh‑Whitefish watersheds drain the county. Mar‑ plies locally in nearby Oakland County; however, the water is quette County relies on both glacial and bedrock aquifers moderately to highly mineralized (Ferris and others, 1954). for ground‑water supplies. According to the February 2005 Wellogic database, approximately 64 percent of the wells in Marquette County are completed in the glacial deposits, and  Summary of Hydrogeologic Conditions by County for the State of Michigan

32 percent in the bedrock units. There is insufficient informa‑ present in the glacial deposits. The upper unconfined aquifer is tion to make this distinction for 4 percent of the wells in the composed of sand and gravel, while the lower confined aquifer county. Glacial deposits overlie the bedrock aquifers in most is composed of fine to coarse sand (Grannemann, 1979). of the county. In the northern portion of the county, the thick‑ Transmissivity values in the Carp Creek area range approxi‑ ness of the glacial deposits is extremely variable and igneous mately between 400 to 11,300 ft2/day, and confined and and metamorphic rocks are directly below the glacial deposits. unconfined aquifers are indicated from storage coefficients Where glacial deposits are thick, small to moderate yields of that range from 0.00004 to 0.4 (Stuart and others, 1967). water may be obtained. In areas where the glacial deposits are Bedrock underlies the glacial deposits when the glacial greater than 50 ft thick and underlain by sedimentary bedrock, deposits are present in Marquette County. The bedrock of water yields are high (Twenter, 1981). Marquette County is composed of Archean igneous and meta‑ Post‑glacial deposits include alluvium and swamp depos‑ morphic rocks, Early metasedimentary rocks, Late its. Alluvium is primarily composed of sand and gravel, while Proterozoic sandstones, Cambrian sandstones, and Ordovician swamp deposits are composed of peat, muck, silt, and clay. sandstones and carbonates. Sedimentary bedrock is near the Water from these deposits may be high in iron, and generally ground surface along the shore of Lake Superior and in the yield small supplies of water (Doonan and VanAlstine, 1982). southeastern portion of Marquette County. The sedimentary Aquifers in the glacial deposits consist largely of sands bedrock dips to the southeast. Here, the sedimentary bedrock and gravels and vary regionally in thickness and permeabil‑ provides the majority of the ground‑water supply. The fol‑ ity. In general, the glacial aquifer appears unconfined. How‑ lowing is true for the sedimentary bedrock in the area. When ever, the aquifer is locally confined, often beneath moraines all layers are present, the Black River Formation underlies (Grannemann, 1984). Glacial deposits range from 0 to 500 ft the glacial deposits. The Black River Formation is capable thick and consist of moraines, outwash, and lacustrine depos‑ of supplying adequate water supplies for domestic use, but its. Moraines range from 0 to hundreds of ft in thickness, and the water may be moderately hard (Doonan and VanAlstine, generally consist of till. Till is composed of clay, silt, sand, 1982). In other areas in the Upper Peninsula shale is found at gravel, and boulders (Doonan and VanAlstine, 1982). Outwash the base of the Black River Formation, which may confine the is comprised of primarily sand and gravel, and the outwash underlying units (Vanlier, 1959). The Prairie du Chien‑Trem‑ ranges in thickness from 0 to 300 ft thick. Sand and gravel pealeau unit, which underlies the Black River Formation, outwash deposits tend to supply the most water. Lacustrine supplies larger amounts of water from its sandstone units deposits range from 0 to 30 ft thick and are composed of strati‑ than from its limestone and dolomite units, which may only fied fine sand, silt, and clay. Water is high in iron and manga‑ be sufficient for domestic water supply. Munising Sandstone nese in glacial deposits and ranges from soft to hard (Twenter, underlies the Prairie du Chien‑Trempealeau unit. The Munis‑ 1981; Grannemann, 1979). ing Sandstone yields moderate supplies of good quality water The Marquette Iron Range is located in the center of that is occasionally hard. The Munising Sandstone is friable Marquette County, and can further be divided into four areas and may introduce sand into some wells (Doonan and VanA‑ based on glacial deposits: the Sands Plain area, the West lstine, 1982). Jacobsville Sandstone underlies the Munising Branch Creek area, the Morgan Creek area, and the Carp Sandstone. Jacobsville Sandstone provides small supplies Creek area. In the Sands Plain area, till consists of primar‑ of water, which may have high chloride and iron content in ily fine sand to clay deposits, although boulder to clay‑sized certain areas. The Jacobsville Sandstone is the main source particles are present. The hydraulic conductivity for moraines of ground‑water supply along the shore of Lake Superior in Sands Plain ranges from 0.5 to 120 ft/day (Grannemann, (Twenter, 1981). Precambrian metasedimentary, igneous, 1984). Grannemann defines areas in Sands Plain as transi‑ and metamorphic rocks underlie the Jacobsville Sandstone in tional deposits, which are interbedded till and outwash (1984). Marquette County. These include the Negaunee Iron Forma‑ Located in the Sands Plain area, the transmissivity values tion. The quality of water from bedrock aquifers varies widely. range approximately from 4,000 to 17,000 ft2/day (Wiitala However, with depth the water becomes more mineralized in and others, 1967). The infiltration rate is high in the Sands bedrock aquifers (Twenter, 1981; Grannemann, 1979). Plain area due to the abundance of sand and gravel outwash (Grannemann, 1979). Compared to the Sands Plain area, the West Branch Creek area outwash is composed of finer Mason County sediments, although it also contains sand and gravel. The Mason County is in the western north‑central part of estimated transmissivity from flow‑net analysis in the West the Lower Peninsula of Michigan. The western portion of the Branch Creek area ranges approximately between 1,000 and county borders the Lake Michigan shoreline. The Pere‑Mar‑ 4,000 ft2/day (Wiitala and others, 1967). The Morgan Creek quette‑White, Manistee, and Lake Michigan watersheds drain area outwash is primarily composed of fine to medium sized Mason County. According to the February 2005 Wellogic grains. The transmissivity for the Morgan Creek area ranges database, approximately 93 percent of the wells in Mason approximately between 660 to 930 ft2/day (Grannemann, County are completed in the glacial deposits, and 0 percent in 1979). The outwash in the Carp Creek area ranges from 150 to 250 ft thick. In the Carp Creek area, a layered system is County Summaries  the bedrock units. There is insufficient information to make to the Public Water Supply database, the estimated transmis‑ this distinction for 7 percent of the wells in the county. sivity for wells completed in till in the county ranges from In the Michigan Basin, the glacial aquifer consists of approximately 1,120 to 10,510 ft2/day. Outwash deposits also sand and gravel that is part of a thick sequence of Pleisto‑ are present in the county. Outwash and composed of primar‑ cene glacial deposits. With the available information, glacial ily sand and gravel (Farrand and Bell, 1982). According to the lithologies cannot be regionally correlated in the subsurface. Public Water Supply database, the estimated transmissivity for This is likely due to the lateral and vertical heterogeneity of outwash wells in the county ranges from approximately 870 to glacial deposits that resulted from a complex depositional 9,310 ft2/day. Bedrock underlies the glacial deposits, but is not history (Westjohn and others, 1994). In Mason County, the currently used for water supplies. thickness of the glacial deposits ranges from 200 to 800 ft. Generally, the thickness increases to the west in the county (Western Michigan University, 1981). Glacial deposits include Menominee County lacustrine deposits, till, and outwash. Lacustrine deposits, Menominee County is in the Upper Peninsula of Michi‑ composed of primarily sand and gravel, are present in the gan. Menominee, Cedar‑Ford, Escanaba, and Lake Michigan western portion of Mason County. Till is found in till plains watersheds drain the county. According to the February 2005 and moraines. Fine‑grained moraines and till plains are found Wellogic database, approximately 8 percent of the wells in interspersed in the central and western portions of the county. Menominee County are completed in the glacial deposits, and Coarse‑grained moraines and till plains are located primar‑ 88 percent in the bedrock units. There is insufficient informa‑ ily in the eastern portion of the county. Outwash is present tion to make this distinction for 4 percent of the wells in the in the eastern and northeastern portions of the county, and is county. composed of primarily sand and gravel. Dune sand is pres‑ Aquifers in the glacial deposits consist largely of sands ent in Mason County along the shore of Lake Michigan and and gravels and vary regionally in thickness and permeability. also scattered inland in areas of the county (Farrand and Bell, Glacial deposits in Menominee County consist of till, out‑ 1982). According to the Public Water Supply database, the wash, and lacustrine deposits. Glacial deposits range from 0 estimated transmissivity for a glacial well in Mason County to 200 ft thick in the county. Drumlins and ground moraines is approximately 3,310 ft2/day. Bedrock underlies the glacial are composed of mostly clayey till that is generally 40 ft thick, deposits, but is not currently used for water supply. but can be up to 100 ft thick. In general, the drumlin and ground‑moraine glacial deposits do not yield large amounts Mecosta County of water. The northern moraine and drumlin deposits contain more sand, and yield more water than those in the southern Mecosta County is in the west‑central part of the Lower portion of the county. Glacial deposits in the western portion Peninsula of Michigan. The Lower Grand, Muskegon, and of the county are thicker and are composed of more sand than Pine watersheds drain Mecosta County. According to the in other areas. This area is capable of yielding large amounts February 2005 Wellogic database, approximately 97 percent of water. The glacial outwash supplies large amounts of water of the wells in Mecosta County are completed in the glacial and is predominantly gravel. In general, the water supply from deposits, and 0 percent in the bedrock units. There is insuf‑ glacial aquifer is hard and occasionally high in iron (Vanlier, ficient information to make this distinction for 3 percent of 1963c). the wells in the county. The northeastern portion of the county The bedrock underlies the glacial deposits. The upper consists of medium‑textured, adequately‑drained soils and portion of the Trenton and Black River Formations form the sandy, well‑drained soils (Michigan Water Resources Com‑ bedrock surface on the east side of the county. This is some‑ mission, 1960). times referred to as the upper‑limestone unit (Vanlier, 1963c). In the Michigan Basin, the glacial aquifer consists of These formations are composed of primarily limestone and sand and gravel that is part of a thick sequence of Pleisto‑ dolomite, with some shale, shaly dolomite, and shaly lime‑ cene glacial deposits. With the available information, glacial stone. The abundance of shale increases in the southern por‑ lithologies cannot be regionally correlated in the subsurface. tion of Menominee County. Most of the wells in the county This is likely due to the lateral and vertical heterogeneity of tap the upper portion of Trenton and Black River Formations. glacial deposits that resulted from a complex depositional his‑ These formations yield water containing hydrogen sulfide tory (Westjohn and others, 1994). In Mecosta County, glacial gas (sulfur water) in the southeast portion of the county. The deposits are approximately 200 to 800 ft thick (Western Michi‑ water from this layer also is high in iron and is hard. This gan University, 1981). Glacial deposits consist of primarily till layer is unconfined and is subject to surface contamination. and outwash. Till is present in till plains and moraines. The Underlying the upper‑limestone layer is the middle‑limestone center of the county is covered in a coarse‑grained moraine. and sandstone layer. This layer forms the bedrock surface in Mostly coarse‑grained till is present in the county. However, the west central portion of the county. The middle‑limestone finer‑grained till occurs in the western and south‑central and sandstone unit includes the St. Peter Sandstone, Prairie du portions of the county (Farrand and Bell, 1982). According Chien Group, and the Trempeleau Formation, and is com‑ 50 Summary of Hydrogeologic Conditions by County for the State of Michigan posed of limestone, dolomite, sandstone, dolomitic sandstone, are present in the county (Farrand and Bell, 1982). According shaly dolomite, and sandy dolomite. The sandstone in this to the Public Water Supply database, the estimated transmis‑ layer thins to the south of the county. The middle‑limestone sivities for glacial wells from aquifer tests in Midland County and sandstone unit mainly supplies water to wells in this area, ranges from 8,020 to 12,660 ft2/day. and in areas where the upper limestone yields sulfur water. In Bedrock underlies the glacial deposits. The bedrock some areas, this aquifer supplies hard and iron rich water. The surface of Midland County is composed of the Jurassic “red middle‑limestone and sandstone layer also yield sulfur water, beds” and the Saginaw Formation (Milstein, 1987). The Juras‑ locally. This aquifer may be considered confined or semi‑con‑ sic “red beds” are generally 50 to 150 ft thick (Westjohn and fined in areas by the shale that is present in the layer. The layer others, 1994). The “red beds” occur primarily in the south‑ beneath is the lower‑sandstone layer. This layer is formed by ern portion of the county (Milstein, 1987). The “red beds” rocks of the Franconia and Dresbach sandstones (Munising consist of red clay, mudstone, siltstone, and sandstone, and Formation), which consists of sandstone that is glauconitic in also include gray‑green shale, gypsum, and mudstone (Shaf‑ some areas. In most areas, this layer is capable of supplying fer, 1969). The “red beds” are considered a confining unit in moderate to large yields of water, but often shallower aquifers Michigan (Westjohn and others, 1994). are used when available. The lower‑sandstone aquifer sup‑ Where the “red beds” are present in the county, the plies water of good quality, except in the southern part of the Saginaw Formation underlies the Jurassic deposits. Interbed‑ county, where it yields extremely hard water. The Precambrian ded sandstone, siltstone, shale, coal, and limestone compose igneous, metamorphic, and sedimentary rocks underlie the the Saginaw Formation. The Saginaw aquifer consists of lower sandstone unit. This layer includes Michigamme Slate, hydraulically connected sandstones in the Saginaw Formation. the Vulcan Iron Formation, Randville Dolomite, and the Quin‑ Within the State, the Saginaw aquifer ranges from less than nesec Formation. This layer is less permeable with depth and 100 to 370 ft in thickness (Westjohn and Weaver, 1996a). The only a few wells in the west‑central portion of the county are Saginaw aquifer yields fresh water in the eastern and northern completed in the Precambrian layer (Vanlier, 1963c). parts of the county. In the central and southwestern portions of Midland County, the Saginaw aquifer yields saline water (Westjohn and Weaver, 1996c). The Saginaw confining unit Midland County underlies the Saginaw aquifer. The Saginaw confining unit is approximately less than 100 to 240 ft thick within the State, Midland County is in the east‑central portion of the and is mostly shale, with thin layers of discontinuous sand‑ Lower Peninsula of Michigan. The Kawkawlin‑Pine, Tit‑ stone, siltstone, limestone, and coal. The permeable layers tabawassee, Pine, and Shiawassee watersheds drain the within the Saginaw confining unit appear to be isolated from county. According to the February 2005 Wellogic database, the regional ground‑water‑flow system (Westjohn and Weaver, approximately 88 percent of the wells in Midland County are 1996a). completed in the glacial deposits, and 9 percent in the bedrock The Saginaw confining unit separates the Saginaw aqui‑ units. There is insufficient information to make this distinction fer from the underlying Parma‑Bayport aquifer. The Parma for 3 percent of the wells in the county. The western side of Sandstone is often considered the basal unit of the Saginaw the county contains primarily glacial wells, while the eastern Formation, although the stratigraphic relationship is not portion of the county contains both glacial and bedrock wells. clear between the Saginaw Formation, Parma Sandstone, and Dune sand is present on the edge of the eastside of the Mississippian‑aged Bayport Limestone. The Parma Sandstone county. However, most of Midland County has poorly‑drained is composed of medium‑ to coarse‑grained sandstone, and soils. The central and eastern portion of the county have sandy, is generally less than 100 ft thick (Cohee and others, 1951). poorly drained soils. In other areas of the county, soils of The Bayport Limestone is a fossiliferous, cherty limestone, intermediate drainage, dry sand, and organic soils are pres‑ often with interbedded sandstone and varies considerably ent (Michigan Water Resources Commission, 1960). Areas of in thickness from one area to another. The Bayport Lime‑ dune sand are present in the central and eastern portion of the stone and Parma Sandstone appear to interfinger throughout county. the Michigan Basin (Westjohn and Weaver, 1996a). These With the available information, glacial lithologies cannot units are hydraulically connected, and together they form be regionally correlated in the subsurface. This is likely due the Parma‑Bayport aquifer (Westjohn and Weaver, 1996a). to the lateral and vertical heterogeneity of glacial deposits that The Parma‑Bayport aquifer is approximately 100 to 150 ft resulted from a complex depositional history. In the Michigan thick within the Michigan Basin. Please note that due to the Basin, the glacial aquifer consists of sand and gravel that is uncertainty of stratigraphic relationship between these units, part of a thick sequence of Pleistocene glacial deposits (West‑ in other reports this aquifer may be delineated differently. The john and others, 1994). Glacial deposits are approximately 600 Parma‑Bayport aquifer yields saline water or brine in Midland to 1,000 ft thick in Midland County (Western Michigan Uni‑ County (Westjohn and Weaver, 1996c). versity, 1981). The glacial deposits are composed of primarily The Michigan Formation underlies the Bayport Lime‑ of lacustrine deposits. Both sand and gravel dominated lacus‑ stone. The Michigan Formation consists of layers of sand‑ trine deposits and clay and silt dominated lacustrine deposits stone, siltstone, anhydrite or gypsum, dolomite, limestone, County Summaries 1 and shale. The lower permeability lithologies of the Michigan transmissivity for glacial wells ranges from approximately Formation are considered a confining unit that separates the 1,960 to 21,270 ft2/day. Bedrock underlies the glacial deposits, Parma‑Bayport aquifer from the underlying Marshall aquifer. but is not currently used for water supplies. The thickness of the Michigan confining unit ranges from less than 50 to 400 ft within the State (Westjohn and Weaver, 1998). Monroe County The Marshall Sandstone underlies the Michigan Forma‑ Monroe County is in the southeastern portion of the tion. The Marshall Sandstone consists of one or more strati‑ Lower Peninsula of Michigan. The Huron, Ottawa‑Stony, graphically continuous permeable sandstones. The upper Raisin, Black‑Rocky, and watersheds cross Monroe sandstone is a quartzarenite to sublitharenite that is referred to County. According to the February 2005 Wellogic database, as the Napoleon Sandstone Member. A shale, siltstone, and/or approximately 4 percent of the wells in Monroe County carbonate layer separates the Napoleon Sandstone Member are completed in the glacial deposits, and 91 percent in the from the underlying lower Marshall sandstone. The lower bedrock units. There is insufficient information to make this Marshall sandstone is comprised of two units. The upper unit distinction for 5 percent of the wells in the county. is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ The uppermost potential aquifer is alluvium. Alluvium enite to sublitharenite. At the base of the Marshall Sandstone is predominantly sand and gravel and rests on glacial deposits is a fine‑ to medium‑grained litharenite that ranges in thick‑ that are present over almost all of the county. With the avail‑ ness from 30 to 125 ft. Permeable sandstones in the Marshall able information, glacial lithologies cannot be regionally cor‑ Sandstone comprise the Marshall aquifer. The Marshall aqui‑ related in the subsurface. This is likely due to the lateral and fer ranges in thickness from 75 to greater than 200 ft within vertical heterogeneity of glacial deposits that resulted from a the State (Westjohn and Weaver, 1998). The Marshall Sand‑ complex depositional history (Westjohn and others, 1994). The stone yields brine in Midland County (Westjohn and Weaver, thickness of glacial deposits varies in Monroe County (ranging 1996c). from 0 ft to greater than 150 ft). Glacial deposits are generally The Coldwater Shale underlies the Marshall Sandstone. about 50 ft thick in most of the county. The bedrock surface The Coldwater Shale consists of primarily shale with interbeds is high trending southwest to northeast from Whiteford to or lenses of sandstone, siltstone, and dolomite. The Coldwater Ash Townships, and in this area glacial deposits are generally Shale is relatively impermeable and is considered a confining only 20 ft thick. Glacial deposits are greater than 150 ft thick unit in most of Michigan (Westjohn and Weaver, 1998). in areas where preglacial valleys were filled, such as in Milan and London Townships. Glacial deposits in Monroe County Missaukee County are composed of glaciolacustrine deposits, till, and glacio‑ fluvial deposits. Except where bedrock outcrops are present, Missaukee County is in the northwestern Lower Penin‑ glaciolacustrine deposits composed of sand and clay form sula of Michigan. The Muskegon and Manistee watersheds the surface of the county. In areas of the county, including drain the county. According to the February 2005 Wellogic Bedford and Whiteford Townships, glaciolacustrine sand com‑ database, approximately 98 percent of the wells in Missaukee poses the surface and directly overlies the bedrock surface. County are completed in the glacial deposits, and 0 percent in The vertical distribution of glacial deposits varies over small the bedrock units. There is insufficient information to make distances. However, to generalize, till underlies the glaciola‑ this distinction for 2 percent of the wells in the county. custrine deposits and is predominately composed of silty clay. In the Michigan Basin, the glacial aquifer consists of The majority of the bedrock surface is covered in till. In Milan sand and gravel that is part of a thick sequence of Pleisto‑ Township a thick package of glaciofluvial deposits is present cene glacial deposits. With the available information, glacial above the bedrock surface. In other areas of the county, glacio‑ lithologies cannot be regionally correlated in the subsurface. fluvial deposits are present in scattered and small amounts in This is likely due to the lateral and vertical heterogeneity of the subsurface (Nicholas and others, 1996). glacial deposits that resulted from a complex depositional his‑ Aquifers in the glacial deposits consist largely of sands tory (Westjohn and others, 1994). The majority of the glacial and gravels and vary regionally in thickness and permeability. deposits in Missaukee County range from 401 to 600 ft thick. Nicholas and others (1996) have termed the aquifer present in However, the thickness of the glacial deposits ranges from 201 the glacial deposits, the sand aquifer. The sand aquifer is com‑ to 1,000 ft in the county (Western Michigan University, 1981). posed of discontinuous glacial sand deposits that are capable The glacial deposits in the county are composed of outwash of yielding small amounts of water. In the northwest portion and till. Outwash is composed predominantly of sand and of the county the sand aquifer is 100 ft below the surface; gravel and is present on the surface of the county. Ice‑contact however, it is generally at shallower depths in other areas of outwash is less abundant, and consists of poorly sorted sand the county. In general, ground‑water flow in the sand aquifer and gravel. In the county, both coarse‑ and fine‑grained till follows topography. In some areas of Monroe County, perched occur in moraines and till plains (Farrand and Bell, 1982). ground water is present where clay deposits above the water According to the Public Water Supply database, the estimated table underlie the isolated sand aquifer. However, due to a  Summary of Hydrogeologic Conditions by County for the State of Michigan high risk of contamination, perched aquifers are not approved Bedford, Ida, Erie, LaSalle, Monroe, Raisinville, Frenchtown, sources of water in Monroe County. The estimated transmis‑ Ash, and Berlin. The Salina Group unconformably underlies sivity for the sand aquifer is 360 ft2/day (Nicholas and others, the Bass Islands Group. In Bedford, Erie, LaSalle, and Monroe 1996). Townships, the southeastern part of the county, the Salina The bedrock in Monroe County consists primarily of Group forms the bedrock surface. The Salina Group consists Devonian and aged carbonates and includes (in of interbeds of dolomite, limestone, and shale. The texture of descending order) the Antrim Shale, Traverse Group, Dundee the dolomite is microcrystalline to sucrosic. The dolomite is Limestone, Detroit River Group, Sylvania Sandstone, Bass fractured and vugs exist with crystals of calcite and celestite. Islands Group, and Salina Group. The bedrock dips to the Fractures and small vugs are also present in the limestone of northwest. In general, the bedrock trends southwest to north‑ the Salina Group (Nicholas and others, 1996). east in descending order across the county. The bedrock sur‑ Nicholas and others (1996) termed the bedrock aquifer face is highest in the central and southwestern portion of the the Silurian‑Devonian aquifer. The southwestern portion of county and dips to the southeast and northwest due to erosion the county has the highest potentiometric surface. The ground (Nicholas and others, 1996). water in the Silurian‑Devonian aquifer generally flows to the The Antrim Shale is the youngest bedrock present in southeast toward Lake Erie and Ohio assuming an isotropic Monroe County. Antrim shale subcrops in areas of Whiteford and homogenous aquifer. The highest amount of recharge to Township. Marcasite and pyrite are present in Antrim Shale. the Silurian‑Devonian aquifer is expected to occur in Sum‑ The Traverse Group comformably underlies the Antrim Shale merfield, Ida, Whiteford, and Bedford Townships due to sand and forms the bedrock surface in areas of Whiteford, Summer‑ overlying a shallow bedrock surface. The southeast portion field, Dundee, and Milan Townships. Pyrite is present through‑ of the county may have the least amount of recharge due to a out the Traverse Group, which consists of beds of shale, lime‑ thicker package of less permeable clay deposits overlying the stone, and dolomite. The Dundee Limestone unconformably bedrock surface. Prior to the development, the Silurian‑Devo‑ underlies the Traverse Group and forms the bedrock surface in nian aquifer was confined over most of the county. Flowing areas of Whiteford, Summerfield, Dundee, London, and Milan wells were present over most of the county (Allen, 1974). Due Townships. Interbedded limestone and dolomite compose the to pumping, however, the Silurian‑Devonian aquifer is now Dundee Limestone. The limestone contains small vugs and unconfined over most of the county. However, the Siluri‑ the dolomite contains vugs and fractures. Celestite and calcite an‑Devonian aquifer appears to be confined in the majority of are minerals that are present in the vugs. Sulfur occurs in the the county (Reeves and others, 2003). In areas of the western fractures at shallow depths (Nicholas and others, 1996). and southwestern portion of the county, the bedrock aquifer The Detroit River Group is further divided into the upper appears to be confined except for bedrock highs, where it is Detroit River Group and the basal Sylvania Sandstone. The unconfined. upper portion of the Detroit River Group unconformably According to slug test results, the estimated transmis‑ underlies the Dundee Limestone and subcrops in areas of sivity of the Silurian‑Devonian aquifer ranges between 10 Whiteford, Summerfield, Dundee, Ida, London, Exeter, Milan, and 6,600 ft2/day, with a median transmissivity of 200 ft2/day. Raisinville, Ash, and Berlin Townships. Sinkholes from this Aquifer tests have also been performed in Monroe County and formation are presenting Ida and Whiteford Townships. Inter‑ are often better estimates of transmissivity. In Summerfield bedded limestone and dolomite compose the upper portion of Township, estimated transmissivity values from an aquifer test the Detroit River Group. The limestone contains small vugs in the bedrock aquifer ranged between 1,000 to 1,300 ft2/day and the dolomite contains vugs and fractures. Celestite and with a storage coefficient ranged between 8.3 x 10‑5 and 1.2 x calcite are minerals that are present in the vugs. Sulfur occurs 10‑4. In Bedford Township, a storage coefficient of 1.0 x 10‑4 in the fractures at shallow depths. Sylvania Sandstone con‑ was estimated and a transmissivity of 3,800 ft2/day from an formably underlies the upper Detroit River Group and is a cal‑ aquifer test performed on the bedrock aquifer (Nicholas and cite cemented, moderately‑ to well‑sorted, quartz sandstone. others, 1996). Pyrite, celestite, calcite, and sulfur are present in areas of the In areas in the county, high concentrations of dissolved sandstone. Sylvania Sandstone forms the bedrock surface in solids, hydrogen sulfide, iron, and manganese were found areas of Whiteford, Summerfield, Bedford, Ida, Erie, LaSalle, in water from the Silurian‑Devonian aquifer. In areas of the Monroe, Raisinville, Frenchtown, Ash, Exeter, and Berlin northern and eastern portion of the county dissolved solid Townships (Nicholas and others, 1996). concentrations exceeded 500 mg/L. In general, water from The contact between Sylvania Sandstone and the underly‑ the Sylvania Sandstone had higher dissolved solids concen‑ ing Bass Islands Group is unconformable. The Bass Islands trations. High sulfate concentrations, exceeding the SMCL, Group consists of beds of limestone and microcrystalline dolo‑ occurred in the eastern portion of the county. Hydrogen mite. The limestone contains small vugs and the dolomite con‑ sulfide concentrations greater than 0.5 mg/L occurred where tains vugs and fractures. Celestite and calcite are minerals that the Dundee Limestone, and Detroit River Dolomite form the are present in the vugs. Sulfur occurs in the fractures at shal‑ bedrock surface. The area trends southeast to northwest from low depths. The Bass Islands Group forms the bedrock surface Summerfield to Ash Townships. Water from wells tapping the in areas of the following Townships: Whiteford, Summerfield, Sylvania Sandstone and Bass Islands Group has the highest County Summaries  concentrations of iron and manganese. (Nicholas and others, However, the thickness of the glacial deposits spans from 101 1996). to 1,000 ft in the county (Western Michigan University, 1981). The glacial deposits in the county are composed of till and outwash. Both medium‑ and coarse‑grained till are present in Montcalm County the county. The Port Huron Moraine trends northwest to south‑ east across the county. The outwash deposits are generally Montcalm County is in the central part of the Lower Pen‑ composed of sand and gravel. Eskers occur in the northeastern insula of Michigan. The Maple, Lower Grand, Muskegon, and portion of the county. Ice‑contact outwash occurs in the south‑ Pine watersheds drain the county. According to the February eastern portion of the county (Farrand and Bell, 1982). 2005 Wellogic database, approximately 98 percent of the wells The bedrock surface in Montmorency County is com‑ in Montcalm County are completed in the glacial deposits, and posed of the Coldwater Shale, Sunbury Shale, Berea Sand‑ 0 percent in the bedrock units. There is insufficient informa‑ stone, Bedford Shale, Antrim Shale, and Traverse Group (Mil‑ tion to make this distinction for 2 percent of the wells in the stein, 1987) which all underlies the glacial deposits. Within county. Glacial wells supply the ground water in the county, the State, the Coldwater Shale consists of primarily shale with because the glacial deposits are thick (Vanlier, 1968). interbeds or lenses of sandstone, siltstone, and dolomite. The In the Michigan Basin, the glacial aquifer consists of sand Coldwater Shale is relatively impermeable and is considered and gravel that is part of a thick sequence of Pleistocene gla‑ a confining unit in most of Michigan (Westjohn and Weaver, cial deposits. With the available information, glacial litholo‑ 1998). gies cannot be regionally correlated in the subsurface. This is The Sunbury Shale is black shale, which thins towards likely due to the lateral and vertical heterogeneity of glacial the center of the basin and is 147.6 ft thick in the eastern por‑ deposits that resulted from a complex depositional history tion of the state (Gutschick and Sandberg, 1991). The Berea (Westjohn and others, 1994). Glacial deposits range in thick‑ Sandstone underlies the Sunbury Shale. The Sunbury Shale is ness between 100 and 800 ft within Montcalm County (Van‑ not generally considered an aquifer. The Berea Sandstone is lier, 1968; Western Michigan University, 1981). Although, the fine‑ to medium‑grained sandstone. It is greater than 114.8 ft majority of the county is covered with 400 to 600 ft of glacial thick in eastern Michigan and thins to the west (Gutschick and deposits (Western Michigan University, 1981). Glacial depos‑ Sandberg, 1991). The Berea Sandstone grades into the under‑ its in the county consist of outwash and till. Outwash is com‑ lying Bedford Shale and thus the upper portion of the shale is posed of primarily sand and gravel. Till is present in till plains silty or sandy. The Bedford Shale is primarily gray shale in the and moraines, and ranges from fine to coarse grained (Vanlier, Michigan Basin. The Bedford Shale may be greater than 213.3 1968; Farrand and Bell, 1982). According to the Public Water ft thick in eastern Michigan and thins toward the center of the Supply database, the estimated transmissivity for glacial wells Michigan Basin (Gutschick and Sandberg, 1991). ranges from approximately 1,240 to 40,100 ft2/day. The water The Antrim Shale is composed of primarily carbona‑ from glacial aquifer may be high in iron and hard to very hard ceous, black to dark‑gray shale. Near the base of the sequence, (Vanlier, 1968). Bedrock underlies the glacial deposits, but is thin layers of gray shale and limestone may occur. The major not currently used for water supplies in the county. constituents in the Antrim Shale consist of quartz, illite, and kerogen. Kaolinite, chlorite, and pyrite also compose Montmorency County the Antrim Shale. The Antrim Shale has been found to have bituminous limestone concretions up to 3 ft in diameter (Mat‑ Montmorency County is in the northeastern Lower Penin‑ thews, 1993). The Antrim Shale can be up to 656 ft thick, sula of Michigan. The Lone Lake‑Ocqueoc, Boardman‑Char‑ which occurs at the center of the Michigan Basin (Gutschick levoix, Cheboygan, and Lake Huron watersheds drain portions and Sandberg, 1991). A few bedrock wells occur where the of the county. According to the February 2005 Wellogic data‑ Antrim Shale forms the bedrock surface. These are located in base, approximately 94 percent of the wells in Montmorency the northeastern portion of the county. County are completed in the glacial deposits, and 1 percent in In Montmorency County, the Traverse Group underlies the bedrock units. There is insufficient information to make the Antrim Shale. The Traverse Group primarily consists of this distinction for 5 percent of the wells in the county. The fossiliferous limestone. In the western portion of the basin, bedrock wells are primarily in the northern portion of the porous dolomite and anhydrite may be present. In the east‑ county. ern portion of the basin, interlayers of shale are common. In the Michigan Basin, glacial aquifers consist of sand (Gardner, 1974). The basal formation of the Traverse Group and gravel that are part of a thick sequence of Pleistocene gla‑ is the Bell Shale. Bell Shale has a maximum thickness of 80 cial deposits. With the available information, glacial litholo‑ ft (Catacosinos and others, 2001). Some bedrock wells occur gies cannot be regionally correlated in the subsurface. This is in the northeastern portion of the county, where the Traverse likely due to the lateral and vertical heterogeneity of glacial Group forms the bedrock surface. deposits that resulted from a complex depositional history (Westjohn and others, 1994). The glacial deposits in Mont‑ morency County generally range from 201 to 600 ft thick.  Summary of Hydrogeologic Conditions by County for the State of Michigan

Muskegon County and Coldwater Shale. The Bayport Limestone is present only along the easternmost edge of the county (Milstein, 1987). The Muskegon County is in the west‑central Lower Peninsula Bayport Limestone consists of limestone, often with interbed‑ of Michigan, along Lake Michigan. The Muskegon, Lower ded sandstone and shale in Muskegon County (McDonald and Grand, Pere Marquette‑White and Lake Michigan watersheds Fleck, 1978). The Parma‑Bayport aquifer is not under Muske‑ drain the county. Thermoelectric and industrial uses withdraw gon County (Westjohn and Weaver, 1996a). the most water in the county. According to the February 2005 The Michigan Formation underlies the Bayport Lime‑ Wellogic database, approximately 98 percent of the wells in stone. The Michigan Formation consists of layers of sand‑ Muskegon County are completed in the glacial deposits, and stone, siltstone, anhydrite or gypsum, dolomite, limestone, 1 percent in the bedrock units. There is insufficient informa‑ and shale. The lower permeability lithologies of the Michigan tion to make this distinction for 1 percent of the wells in the Formation are considered a confining unit that separates the county. The Marshall aquifer is the most productive bedrock Parma‑Bayport aquifer from the underlying Marshall aquifer. aquifer in the County (Vanlier, 1968). The thickness of the Michigan confining unit ranges from In the Michigan Basin, the glacial aquifer consists of less than 50 to 400 ft within the State (Westjohn and Weaver, sand and gravel that is part of a thick sequence of Pleisto‑ 1998). However, in the southeastern portion of the county, the cene glacial deposits. With the available information, glacial Michigan Formation may yield small to moderate quantities of lithologies cannot be regionally correlated in the subsurface. highly mineralized water (Vanlier, 1968) This is likely due to the lateral and vertical heterogeneity of The Marshall Sandstone underlies the Michigan Forma‑ glacial deposits that resulted from a complex depositional tion. At the Muskegon County wastewater disposal system history (Westjohn and others, 1994). In Muskegon County, site, the Marshall Sandstone ranges in thickness from 0 to glacial deposits range from 100 to 800 ft thick. Most of the 300 ft, from west to east (McDonald and Fleck, 1978). The county is covered in 200 to 400 ft of glacial deposits (Western Marshall Sandstone underlies the Michigan Formation. The Michigan University, 1981). Predominantly outwash cov‑ Marshall Sandstone consists of one or more stratigraphically ers the north‑central and north‑eastern portion of the county continuous permeable sandstones. The upper sandstone is a (Farrand and Bell, 1982). Outwash is composed of sand and quartzarenite to sublitharenite that is referred to as the Napo‑ gravel. Primarily lacustrine deposits cover the western, central, leon Sandstone Member. A shale, siltstone, and/or carbonate and southern portions of the county. The lacustrine deposits layer separates the Napoleon Sandstone Member from the are composed of primarily sand and gravel (Farrand and Bell, underlying lower Marshall sandstone. The lower Marshall 1982). Till deposits occur in the northwestern and southeastern sandstone is comprised of two units. The upper unit is gener‑ parts of the county. Dune deposits are scattered throughout the ally 50 to 125 ft of fine‑ to medium‑grained quartzarenite county and are especially abundant along the shore of Lake to sublitharenite. At the base of the Marshall Sandstone is a Michigan (Farrand and Bell, 1982). According to the Public fine‑ to medium‑grained litharenite that ranges in thickness Water Supply database, the estimated transmissivity for glacial from 30 to 125 ft. Permeable sandstones in the Marshall Sand‑ wells ranges from approximately 990 to 6,015 ft2/day. stone comprise the Marshall aquifer. The Marshall aquifer Near the central‑eastern corner of Muskegon County, ranges in thickness from 75 to greater than 200 ft within the where it borders only Newaygo County, is a wastewater State (Westjohn and Weaver, 1998). According to the Public disposal system, which was the subject of a study by McDon‑ Water Supply database, the estimated transmissivity for a well ald and Fleck (1978). This study area included portions of completed in the Marshall Sandstone in Muskegon County is Muskegon, Newaygo, Kent, and Ottawa Counties. The western approximately 2,635 ft2/day. The Marshall aquifer is confined portion of the wastewater site is composed of 20 to 80 ft of in areas of Muskegon County by the overlying impermeable well‑sorted sand that is interbedded with fine gravel and silt. glacial deposits or bedrock. The Marshall aquifer yields both Underneath this is primarily silt and clay. The eastern portion fresh and saline water in Muskegon County (Vanlier, 1968; of the waste water site is primarily silt and clay‑rich till inter‑ Westjohn and Weaver, 1996c). Household wells that yield layered with sand and gravel (McDonald and Fleck, 1978). An water from the Marshall Sandstone are located primarily in the irrigation circle located in Muskegon County at the Muskegon western and southern edges of the county. County Wastewater Facility was investigated. The upper por‑ The Coldwater Shale underlies the Marshall Sandstone, tion of the glacial deposits at the irrigation circle are composed and forms the bedrock surface in the northwestern and south‑ of 16 to 20 ft of fine to medium‑grained sand. Approximately western portions of the county (Milstein, 1987). The Coldwa‑ 33 ft (10 m) of silty sand interlayered with silty clay, below the ter Shale consists of primarily shale with interbeds or lenses sand layer. Underneath this is a layer of silty‑clay till. Using of sandstone, siltstone, and dolomite. The Coldwater Shale is a steady‑state parameter‑estimation model of the irrigation relatively impermeable and is considered a confining unit in circle, hydraulic conductivity was estimated and ranges from most of Michigan (Westjohn and Weaver, 1998). 155 to 110 ft/day (McDonald , 1980). Bedrock underlies the glacial deposits. The bedrock surface in Muskegon County, from east to west, consists of the Bayport Limestone, Michigan Formation, Marshall Sandstone County Summaries 

Newaygo County Interbedded sandstone, siltstone, shale, coal, and lime‑ stone compose the Saginaw Formation, which underlies the Newaygo County is in the west‑central part of the Lower Jurassic “red beds” where “red beds” are present. Sandstone Peninsula of Michigan. The Lower Grand, Muskegon, and in the Saginaw Formation is the Saginaw aquifer (Westjohn Pere Marquette‑White watersheds drain the county Accord‑ and Weaver, 1996a). The Saginaw aquifer ranges from less ing to the February 2005 Wellogic database, approximately 99 than 100 to 370 ft thick within the State. The Saginaw aquifer percent of the wells in Newaygo County are completed in the yields saline water in Newaygo County (Westjohn and Weaver, glacial deposits, and less than 1 percent in the bedrock units. 1996c). The Saginaw confining unit underlies the Saginaw There is insufficient information to make this distinction for 1 aquifer. The Saginaw confining unit is approximately less than percent of the wells in the county. 100 to 240 ft thick within the State, and is mostly shale, with In the Michigan Basin, the glacial aquifer consists of thin layers of discontinuous sandstone, siltstone, limestone, sand and gravel that is part of a thick sequence of Pleisto‑ and coal. The permeable layers within the Saginaw confining cene glacial deposits. With the available information, glacial unit appear to be isolated from the regional ground‑water‑flow lithologies cannot be regionally correlated in the subsurface. system (Westjohn and Weaver, 1996a). This is likely due to the lateral and vertical heterogeneity of The Saginaw confining unit separates the Saginaw aqui‑ glacial deposits that resulted from a complex depositional fer from the underlying Parma‑Bayport aquifer. The Parma history (Westjohn and others, 1994). Glacial deposits range in Sandstone is often considered the basal unit of the Saginaw thickness from 100 to 800 ft in Newaygo County. The major‑ Formation, although the stratigraphic relationship is not ity of the county is covered in 200 to 400 ft of glacial deposits clear between the Saginaw Formation, Parma Sandstone, and (Western Michigan University, 1981). Glacial deposits are Mississippian‑aged Bayport Limestone. The Parma Sandstone composed primarily of outwash and till. Outwash is inter‑ is composed of medium‑ to coarse‑grained sandstone, and spersed throughout the county (Farrand and Bell, 1982). is generally less than 100 ft thick (Cohee and others, 1951). Outwash is composed of primarily sand and gravel. Till is The Bayport Limestone is a fossiliferous, cherty limestone, present in till plains and moraines. Mostly coarse‑grained till often with interbedded sandstone and varies considerably is present in the county; however, in the southern portion of in thickness from one area to another. The Bayport Lime‑ the county, fine to medium‑grained till is present (Farrand and stone and Parma Sandstone appear to interfinger throughout Bell, 1982). According to the Public Water Supply database, the Michigan Basin (Westjohn and Weaver, 1996a). These the estimated transmissivity for glacial wells ranges from units are hydraulically connected, and together they form approximately 6,000 to 13,370 ft2/day. the Parma‑Bayport aquifer (Westjohn and Weaver, 1996a). Near the central‑eastern corner of Muskegon County, The Parma‑Bayport aquifer is approximately 100 to 150 ft where it borders only Newaygo County, is a wastewater thick within the Michigan Basin. Please note that due to the disposal system, which was the subject of a study by McDon‑ uncertainty of stratigraphic relationship between these units, ald and Fleck (1978). This study area included portions of in other reports this aquifer may be delineated differently. Muskegon, Newaygo, Kent, and Ottawa Counties. The western The Parma‑Bayport aquifer may yield saline water or brine in portion of the wastewater site is composed of 20 to 80 ft of Newaygo County (Westjohn and Weaver, 1996c). well‑sorted sand that is interbedded with fine gravel and silt. The Michigan Formation underlies the Bayport Lime‑ Underneath this is primarily silt and clay. The eastern portion stone. The Michigan Formation consists of layers of sand‑ of the waste water site is primarily silt and clay‑rich till inter‑ stone, siltstone, anhydrite or gypsum, dolomite, limestone, layered with sand and gravel (McDonald and Fleck, 1978). and shale. The lower permeability lithologies of the Michigan Bedrock underlies the glacial aquifer. Formation are considered a confining unit that separates the The bedrock surface of Newaygo County is composed Parma‑Bayport aquifer from the underlying Marshall aquifer. (from east to west) of the Jurassic “red beds”, Saginaw Forma‑ The thickness of the Michigan confining unit ranges from tion, Bayport Limestone, and Michigan Formation (Milstein, less than 50 to 400 ft within the State (Westjohn and Weaver, 1987). The “red beds” consist of red clay, mudstone, siltstone, 1998). and sandstone, and also include gray‑green shale, gypsum, and The Marshall Sandstone underlies the Michigan Forma‑ mudstone (Shaffer, 1969). The Jurassic “red beds” generally tion. The Marshall Sandstone consists of one or more strati‑ range between 50 to 150 ft in thickness when present, and may graphically continuous permeable sandstones. The upper be up to 200 ft thick. The “red beds” are often poorly consoli‑ sandstone is a quartzarenite to sublitharenite that is referred to dated or unconsolidated and consist primarily of clay, mud‑ as the Napoleon Sandstone Member. A shale, siltstone, and/or stone, siltstone, sandstone, shale, and gypsum. The “red beds” carbonate layer separates the Napoleon Sandstone Member are relatively impermeable and are considered a confining from the underlying lower Marshall sandstone. The lower unit, that impedes the vertical flow of water between glacial Marshall sandstone is comprised of two units. The upper unit and bedrock aquifers. In the west‑central portion of the State, is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ the “red beds” are usually present over the saline‑water‑bear‑ enite to sublitharenite. At the base of the Marshall Sandstone ing Pennsylvanian rocks (Westjohn and others, 1994). is a fine‑ to medium‑grained litharenite that ranges in thick‑ ness from 30 to 125 ft. Permeable sandstones in the Marshall  Summary of Hydrogeologic Conditions by County for the State of Michigan

Sandstone comprise the Marshall aquifer. The Marshall aqui‑ are generally deeper than 40 ft, primarily in the northern por‑ fer ranges in thickness from 75 to greater than 200 ft within tion of Oakland County. High nitrate concentrations in ground the State (Westjohn and Weaver, 1998). The Marshall aquifer water from glacial aquifer are common in almost every town‑ is capable of supplying large quantities of water. The Marshall ship in Oakland County. Chloride occurs in water from glacial aquifer yields saline water or brine in Newaygo County (West‑ wells, but generally has higher concentrations in bedrock wells john and Weaver, 1996c). (Aichele and others, 1998). The Coldwater Shale underlies the Marshall Sandstone. Bedrock underlies the glacial deposits. Bedrock aquifers The Coldwater Shale consists of primarily shale with interbeds in Oakland County rarely yield potable water due to areas or lenses of sandstone, siltstone, and dolomite. The Coldwater where the water has high concentrations of sulfate, iron, Shale is relatively impermeable and is considered a confining chloride, and dissolved solids (Aichele, 2000). The bedrock unit in most of Michigan (Westjohn and Weaver, 1998). surface, in the county, consists of the Marshall Sandstone, Coldwater Shale, Sunbury Shale, Berea Sandstone, Bedford Shale, and Antrim Shale. Locally, the Coldwater Shale has Oakland County sandstone units in areas of the county that may yield suffi‑ cient supplies of water. In addition, Berea Sandstone and the Oakland County is in the southeastern portion of the Marshall Sandstone yield sufficient amounts of water in areas Lower Peninsula of Michigan. The Shiawassee, Flint, St. Clair, of the county (Twenter, 1975). High nitrate concentrations in Clinton, Detroit, and Huron watersheds are included in the ground‑water from bedrock aquifers are common in almost county. According to the February 2005 Wellogic database, every township in Oakland County. High chloride concentra‑ approximately 94 percent of the wells in Oakland County are tions occur in ground water in several areas of the county completed in the glacial deposits, and 2 percent in the bedrock (Aichele and others, 1998). units. There is insufficient information to make this distinction The Marshall Sandstone consists of one or more strati‑ for 4 percent of the wells in the county. graphically continuous permeable sandstones. The upper With the available information, glacial lithologies cannot sandstone is a quartzarenite to sublitharenite that is referred to be regionally correlated in the subsurface. This is likely due as the Napoleon Sandstone Member. A shale, siltstone, and/or to the lateral and vertical heterogeneity of glacial deposits that carbonate layer separates the Napoleon Sandstone Member resulted from a complex depositional history (Westjohn and from the underlying lower Marshall sandstone. The lower others, 1994). The northwestern portion of the Clinton River Marshall sandstone is comprised of two units. The upper unit basin is located in northwestern Oakland County. The soils are is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ poorly to well‑drained sand loamy sand, silty sand, silty loam, enite to sublitharenite. At the base of the Marshall Sandstone clay loam, limy loam, clay, and loam in this area of Oakland is a fine‑ to medium‑grained litharenite that ranges in thick‑ County (Twenter, 1975). Infiltration rates vary throughout the ness from 30 to 125 ft. Permeable sandstones in the Marshall county (Aichele, 2000). Glacial deposits range in thickness Sandstone comprise the Marshall aquifer. The Marshall aqui‑ from 20 to 350 ft, generally increasing to the northwest. The fer ranges in thickness from 75 to greater than 200 ft within glacial deposits consist of moraines, till plains, lacustrine, and the State (Westjohn and Weaver, 1998). The Marshall Sand‑ outwash. Till plains consist of poorly sorted clay, sand, gravel, stone produces adequate water supplies in Holly, Groveland, and boulders. Sand and clay compose the lacustrine (Ferris Brandon, and Rose Townships, all located in the northeastern and others, 1954). In the southeastern portion of the county, portion of Oakland County. However, in this area, glacial wells clay lacustrine deposits are common (Aichele, 2000). Outwash are still the main source of water (Aichele, 2000). According generally consists of well‑sorted sand and gravel (Ferris and to the Public Water Supply database, the estimated transmis‑ others, 1954). The central portion of Oakland County has an sivity for wells completed in the Marshall aquifer in Oakland outwash plain trending northeast to southwest (Aichele, 2000). County ranges from approximately 14,225 to 16,515 ft2/day. Aquifers in the glacial deposits consist largely of sands The Marshall aquifer supplies predominately fresh water in and gravels and vary regionally in thickness and permeability. Oakland County. In the northeastern most corner of the county, According to the Public Water Supply database, the estimated the Marshall aquifer may contain saline water (Westjohn and transmissivity for glacial wells in the county from approxi‑ Weaver, 1996c). The Marshall aquifer may yield water with mately 735 to greater than 43,200 ft2/day. According to Twen‑ high concentrations of arsenic in areas of the county (Aichele ter and Knutilla (1972) and Ferris and others (1954), the trans‑ and others, 1998). missivity of the glacial aquifer ranges between approximately The Coldwater Shale consists of shale, sandstone, silt‑ 1,470 and 26,700 ft2/day. The storage coefficient ranges from stone, and carbonates and underlies the Marshall Sandstone. 4.0 x 10‑4 to 3.4 x 10‑5 for the glacial aquifer (Ferris and oth‑ The Coldwater Shale is generally considered to be a confining ers, 1954). The glacial aquifer is confined in certain areas and unit and ranges in thickness, from 500 to 1,300 ft, from east unconfined in others (Wisler, 1952). Water from glacial wells to west across the State. More sandstone beds are present in is moderately hard in the Clinton River Basin. Chloride and the Coldwater Shale in the eastern part of the State (Monnett, dissolved solid concentrations increase with depth in glacial 1948). Also, locally in Oakland County, the Coldwater Shale wells (Twenter, 1975). Arsenic also occurs in glacial wells that may yield freshwater where it is near the surface, but yields County Summaries  mineralized water with depth (Ferris and others, 1954). The in the central and eastern portions of the county. However, Coldwater Shale may yield water with high concentrations of in the southwest and northwest portion of the county, fine to arsenic in areas of the county (Aichele and others, 1998). medium‑grained till is present. Lacustrine deposits, primar‑ The Sunbury Shale underlies the Coldwater Shale. The ily composed of sand and gravel, are present in the northern Sunbury Shale ranges in thickness from 0 to 50 ft and is gener‑ portion of the county (Farrand and Bell, 1982). According to ally slightly calcareous shale with areas of pyrite. Sunbury the Public Water Supply database, the estimated transmissivity Shale yields little, if any, water that is mineralized with depth. for glacial wells ranges from approximately 3,530 to 10,775 Berea Sandstone underlies Sunbury Shale. The Berea Sand‑ ft2/day. Bedrock underlies the glacial deposits, and is not cur‑ stone ranges in thickness from 0 to 100 ft, and consists of rently used for water supplies. two to three sandstones separated by shale. The upper unit is a fine‑grained, cemented silty and/ or shaly, dolomitic sand‑ stone that contains micas and pyrite in areas. The middle unit Ogemaw County is more friable and consists of fine to medium sandstone with Ogemaw County is in the northeastern Lower Peninsula beds of shale and well‑cemented sandstone. The lower unit is of Michigan. The Au Sable, Au Gres‑Rifle, and Tittabawas‑ a fine‑grained, cemented, silty and/ or shaly, dolomitic sand‑ see watersheds drain the county. The southwestern corner of stone that contains micas and pyrite in areas, but contains less Ogemaw County is drained by the Tittabawassee River. This pyrite and more shale. The middle unit dominates the Berea area consists of well‑drained soils, adequately drained soils, Sandstone in the southeastern portion of Oakland County (Fer‑ and sands (Michigan Water Resources Commission, 1960). ris and others, 1954). Saline water has been recorded in wells The Saginaw Lowlands cross the southern portion of the tapping the Berea Sandstone in Independence Township near county. According to the February 2005 Wellogic database, 1,000 ft in depth (Mozola, 1954). The Bedford Shale under‑ approximately 91 percent of the wells in Ogemaw County are lies the Berea Sandstone. The Bedford Shale is 0 to 100 ft in completed in the glacial deposits, and 5 percent in the bedrock thick and consists of shale, sandy shale, and shaly limestone. units. There is insufficient information to make this distinction Antrim Shale underlies Bedford Shale. Antrim Shale is com‑ for 4 percent of the wells in the county. Water from the glacial posed of shale with concretions of pyrite and anthraconite. The wells may be hard or have a high iron content. Bedrock wells thickness of Antrim Shale ranges between 70 to 170 ft, and are primarily located in the central and eastern parts of the locally may yield small water supplies. However, the water is county. In areas of the county, bedrock wells may provide very moderately to highly mineralized. The Antrim Shale forms the hard and/or saline water (Knutilla and others, 1971). bedrock surface in the southeastern portion of Oakland County Glacial deposits range from 11 to 800 ft thick in the (Ferris and others, 1954). county (Western Michigan University, 1981). The glacial deposits in Ogemaw County consist of till, lacustrine, and Oceana County outwash deposits. Till is predominant in the central and east‑ ern portions of the county. The till ranges from fine to coarse Oceana County is in the west‑central part of the Lower grained, but the majority of the till is fine grained. The lacus‑ Peninsula of Michigan. The western edge of the county trine deposits are primarily coarse‑grained and are dominant in borders the Lake Michigan shoreline. The Lake Michigan the south‑central portion of the county. Outwash and ice‑con‑ and Pere‑Marquette‑White watersheds drain Oceana County. tact outwash are abundant within in the northern portion of the According to the February 2005 Wellogic database, approxi‑ county, and both are primarily composed of sand and gravel mately 99 percent of the wells in Oceana County are com‑ (Farrand and Bell, 1982). In the upper Rifle River basin, which pleted in the glacial deposits, and 0 percent in the bedrock is located in the north‑central portion of the county, the glacial units. There is insufficient information to make this distinction deposits are up to 700 ft thick and are primarily composed for 1 percent of the wells in the county. of sand and gravel in the upland areas. In lowland areas, the In the Michigan Basin, the glacial aquifer consists of glacial deposits are composed of layers of sand and gravel and sand and gravel that is part of a thick sequence of Pleisto‑ clay. The glacial aquifer is confined in areas of the upper Rifle cene glacial deposits. With the available information, glacial River basin, and many wells that tap this aquifer are flowing lithologies cannot be regionally correlated in the subsurface. wells (Knutilla and others, 1971). According to the Public This is likely due to the lateral and vertical heterogeneity of Water Supply database, the estimated transmissivity for glacial glacial deposits that resulted from a complex depositional wells in the county ranges from approximately 270 to 1,960 history (Westjohn and others, 1994). The thickness of the ft2/day. glacial deposits ranges from 200 to 800 ft in Oceana County The bedrock surface of Ogemaw County is composed of (Western Michigan University, 1981). Glacial deposits the Saginaw Formation, Bayport Limestone, Michigan Forma‑ consist of outwash and till. Outwash is interspersed through tion, Marshall Sandstone, and Coldwater Shale. Local folding the central and eastern portions of the county. Outwash is and erosion caused the Marshall Sandstone and Coldwater composed of sand and gravel. Till is present in till plains and Shale to form the bedrock surface in areas trending northwest moraines. Coarse‑grained moraines and till plains are located to southeast across the county.  Summary of Hydrogeologic Conditions by County for the State of Michigan

The Saginaw Formation forms the bedrock surface in enite to sublitharenite. At the base of the Marshall Sandstone the southwestern portion of the county, and is composed of is a fine‑ to medium‑grained litharenite that ranges in thick‑ interbedded sandstone, siltstone, shale, coal, and limestone. ness from 30 to 125 ft. Permeable sandstones in the Marshall The Saginaw aquifer consists of hydraulically‑connected Sandstone comprise the Marshall aquifer. The Marshall sandstones in the Saginaw Formation (Westjohn and Weaver, aquifer ranges in thickness from 75 to greater than 200 ft 1996a). Within the State, the Saginaw aquifer ranges from within the State (Westjohn and Weaver, 1998). The Marshall less than 100 to 370 ft thick. The Saginaw aquifer contains aquifer contains both saline and fresh water in the western and fresh water in the southwestern portion of Ogemaw County eastern portions of Ogemaw County, respectively (Westjohn (Westjohn and Weaver, 1996c). The Saginaw confining unit and Weaver, 1996c). underlies the Saginaw aquifer and ranges in thickness between The Coldwater Shale underlies the Marshall Sandstone 50 and 240 ft within the State. It is primarily shale, with thin and is composed of primarily shale with interbeds, or lenses, layers of discontinuous sandstone, siltstone, limestone, and of sandstone, siltstone, and dolomite. The Coldwater Shale is coal. The permeable layers within the Saginaw confining unit relatively impermeable and is considered a confining unit in appear to be isolated from the regional ground‑water‑flow most of Michigan (Westjohn and Weaver, 1998). system (Westjohn and Weaver, 1996a). The Saginaw confining unit separates the Saginaw aqui‑ fer from the underlying Parma‑Bayport aquifer. The Parma Ontonagon County Sandstone is often considered the basal unit of the Saginaw Ontonagon County is in the western Upper Peninsula of Formation, although the stratigraphic relationship is not Michigan. The Black‑Presque Isle, Ontonagon, Brule, Stur‑ clear between the Saginaw Formation, Parma Sandstone, and geon, Keweenaw Peninsula, and Lake Superior watersheds Mississippian‑aged Bayport Limestone. The Parma Sandstone drain the county. Doonan and Hendrickson (1969) reported is composed of medium‑ to coarse‑grained sandstone, and that ground water supplies are scarce in Ontonagon County. is generally less than 100 ft thick (Cohee and others, 1951). According to the February 2005 Wellogic database, approxi‑ The Bayport Limestone is a fossiliferous, cherty limestone, mately 36 percent of the wells in Ontonagon County are com‑ often with interbedded sandstone and varies considerably pleted in the glacial deposits, and 59 percent in the bedrock in thickness from one area to another. The Bayport Lime‑ units. There is insufficient information to make this distinction stone and Parma Sandstone appear to interfinger throughout for 5 percent of the wells in the county. Most of the wells in the Michigan Basin (Westjohn and Weaver, 1996a). These the county are drilled wells that range from 50 to 300 ft in units are hydraulically connected, and together they form depth. However, dug wells, ranging from 10 to 20 ft in depth, the Parma‑Bayport aquifer (Westjohn and Weaver, 1996a). also supply small amounts of water. Enlarged springs add to The Parma‑Bayport aquifer is approximately 100 to 150 ft the supply of water in the county, and are generally around 4 ft thick within the Michigan Basin. Please note that due to the in depth. uncertainty of stratigraphic relationship between these units, Aquifers in the glacial deposits consist largely of sands in other reports this aquifer may be delineated differently. The and gravels, and vary regionally in thickness and permeability. Parma‑Bayport aquifer contains fresh water in the southwest‑ Glacial deposits are from 0 to 300 ft thick in the county, and ern most portion of Ogemaw County (Westjohn and Weaver, composed of lacustrine deposits, beach sand, till, and outwash. 1996c). Lacustrine deposits are composed of clay, silt, and sand. Most Underlying the Bayport Limestone is the Michigan For‑ wells that tap lacustrine deposits, obtain water from the sandy mation. The Michigan Formation forms the bedrock surface deposits, however, shallow wells may obtain very small sup‑ in the majority of the county. The Michigan Formation is plies of water from silt and clay. Beach sands in Ontonagon composed of sandstone, shale, limestone, and occasional dolo‑ County yield water for the public supply near Lake Superior. mite. Gypsum and anhydrite are also present in the formation. Lacustrine deposits often supply water that has high chloride The lower permeability lithologies of the Michigan Forma‑ content, but may still be suitable for domestic use. Water tion are considered to be a confining unit that separates the from lacustrine deposits also has a high iron concentration Parma‑Bayport aquifer from the underlying Marshall aquifer. in Ontonagon County. Till plains and moraines are primar‑ The Michigan confining unit is approximately 50 to 400 ft ily composed of sandy to clayey till. In the southeast portion thick within the State (Westjohn and Weaver, 1998). of the county, moderate water supplies are obtained from The Marshall Sandstone underlies the Michigan Forma‑ wells completed in till that is less than 100 ft deep. Outwash tion. The Marshall Sandstone consists of one or more strati‑ is not abundant in Ontonagon County, but in areas where it is graphically continuous permeable sandstones. The upper present, this deposit yields moderate amounts of water. These sandstone is a quartzarenite to sublitharenite that is referred to areas are southeast of Paulding and southeast of Rousseau. In as the Napoleon Sandstone Member. A shale, siltstone, and/or general, sand and gravel are more abundant in the southern carbonate layer separates the Napoleon Sandstone Member portion of the county, and therefore, the glacial deposits sup‑ from the underlying lower Marshall sandstone. The lower ply sufficient quantities of water in this region (Doonan and Marshall sandstone is comprised of two units. The upper unit Hendrickson, 1969). Estimated transmissivity for the glacial is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ County Summaries  aquifer ranges between 123 to 1,331 ft2/day. Transmissivity Coarse‑grained moraines and till plains are in the western estimations were calculated from the specific capacity data of and central portions of the county. Till of finer grain size is Doonan and Hendrickson (1969). located primarily in the eastern portion of the county (Farrand In areas where glacial deposits cannot supply adequate and Bell, 1982). Glacial wells in the county, according to the amounts of water, wells are drilled to the bedrock aquifer. Public Water Supply database, have estimated transmissivi‑ The estimated transmissivity for the bedrock aquifer ranges ties from aquifer tests that range from approximately 3,075 to between 19 and 449 ft2/day. Transmissivity estimations were 17,425 ft2/day. Bedrock underlies the glacial deposits, but is calculated from the specific capacity data of Doonan and not currently used for water supply. Hendrickson (1969). In southern Ontonagon County, Jacobsville Sandstone underlies the glacial deposits. Moderate supplies of water are Oscoda County obtained from Jacobsville Sandstone wells that are 100 to 300 Oscoda County is in the northeastern portion of the ft in depth. Jacobsville Sandstone occasionally yields water Lower Peninsula of Michigan. The Thunder Bay and Au Sable with high iron concentrations in Ontonagon County. In the watersheds drain the county. According to the February 2005 northern portion of the county, Freda Sandstone and Nonesuch Wellogic database, approximately 98 percent of the wells in Shale underlie the glacial deposits. Shallower wells in this Oscoda County are completed in the glacial deposits. bedrock yield fresh water supplies. However, wells that are In the Michigan Basin, glacial aquifers consist of sand deeper than 75 ft near Lake Superior and are deeper than 150 and gravel that are part of a thick sequence of Pleistocene gla‑ ft elsewhere in the county often yield saline water. The iron cial deposits. With the available information, glacial litholo‑ content in the Freda Sandstone and Nonesuch Shale is high in gies cannot be regionally correlated in the subsurface. This is some areas and the water is hard. likely due to the lateral and vertical heterogeneity of glacial Ancient lava flows are exposed in the Porcupine Moun‑ deposits that resulted from a complex depositional history tains area, interbedded with conglomerate, shale, and sand‑ (Westjohn and others, 1994). Glacial deposits range from 101 stone. Water from this source is often high in iron content, is to 1,000 ft in thickness (Western Michigan University, 1981). saline, and is hard. The older volcanics, such as the Animikie The glacial deposits in Oscoda County consist of till, outwash, series in the southernmost portion of the county, are not used and lacustrine deposits. Fine‑ to coarse‑grained till is pres‑ to supply water, because the overlying glacial aquifer is gener‑ ent in the county in moraines and till plains. The Port Huron ally satisfactory (Doonan and Hendrickson, 1969). According Moraine trends northwest to southeast across a portion of the to the Public Water Supply database, however, the estimated county. Outwash, composed of sand and gravel, is present transmissivity for a bedrock well completed in basalt is in the county. Isolated areas of ice‑contact outwash occur in approximately 100 ft2/day. the northern‑central and southern portion of Oscoda County. Areas of fine‑grained lacustrine deposits are in the central Osceola County portion of the county (Farrand and Bell, 1982). A glacial well in the county, according to the Public Water Supply database, Osceola County is in the north‑central Lower Peninsula has an estimated transmissivity from an aquifer test that is of Michigan. The Muskegon, Manistee, and Pine watersheds approximately 2,937 ft2/day. Bedrock underlies the glacial are included in the county. According to the February 2005 deposits, but is not currently used for water supply. Wellogic database, approximately 98 percent of the wells in Osceola County are completed in the glacial deposits, and 0 percent in the bedrock units. There is insufficient informa‑ Otsego County tion to make this distinction for 2 percent of the wells in the Otsego is in the central‑northern portion of the Lower county. Peninsula of Michigan. The Manistee, Boardman‑Charlevoix, In the Michigan Basin, glacial aquifers consist of sand Cheboygan, Black, Au Sable watersheds drain portions of and gravel that are part of a thick sequence of Pleistocene Otsego County. According to the February 2005 Wellogic glacial deposits. With the available information, glacial database, approximately 92 percent of the wells in Otsego lithologies cannot be regionally correlated in the subsurface. County are completed in the glacial deposits, and 0 percent in This is likely due to the lateral and vertical heterogeneity of the bedrock units. There is insufficient information to make glacial deposits that resulted from a complex depositional this distinction for 8 percent of the wells in the county. history (Westjohn and others, 1994). Glacial deposits range in In the Michigan Basin, glacial aquifers consist of sand thickness from 400 to 1,000 ft in Osceola County. Generally, and gravel that are part of a thick sequence of Pleistocene the thickness of the glacial deposits increases to the north‑ glacial deposits. With the available information, glacial west (Western Michigan University, 1981). In the county, the lithologies cannot be regionally correlated in the subsurface. glacial deposits consist of primarily till and outwash. Outwash This is likely due to the lateral and vertical heterogeneity of is interspersed throughout the county and composed primarily glacial deposits that resulted from a complex depositional of sand and gravel. Till is present in till plains and moraines. history (Westjohn and others, 1994). The glacial deposits in 60 Summary of Hydrogeologic Conditions by County for the State of Michigan

Otsego County range from 201 to greater than 1,000 ft thick in two channels, the south channel and the east channel. The (Western Michigan University, 1981). The majority of glacial south channel occurs northeast of Holland, and continues deposits in Otsego County are composed of sand and gravel westward along the shared Ottawa and Allegan County line. outwash deposits. In the southern portion of the county are The south channel is an approximately 400 ft thick, confined areas of ice‑contact outwash. The northeastern portion of the aquifer that varies in permeability, and yields highly mineral‑ county is also composed coarse‑grained till. Both medium‑ ized water. The east channel trends southeast to northwest and and coarse‑grained till is present in a moraine, which trends occurs along the eastern Holland city limit. The east channel is northwest to southeast across in the county (Farrand and Bell, a confined aquifer that is up to 100 ft thick. The east channel 1982). According to the Public Water Supply database, the supplies good quality water. The transmissivity in the east estimated transmissivity for glacial wells ranges from approxi‑ channel ranges from 5,347 to 13,902 ft2/day. Lenses of out‑ mately 690 to 35,450 ft2/day. Bedrock underlies the glacial wash also occur interbedded within the till deposits (Deutsch deposits, but is not currently used for water supplies in the and others, 1958). county. Till occurs primarily in the southern and eastern portions of the county (Vanlier, 1968; Farrand and Bell, 1982). In gen‑ eral, the morainal deposits and till plains consist of till that has Ottawa County a high porosity, but low permeability. Till generally contains boulders, gravel, and sand in a clay and silt matrix. In some Ottawa County is in the western Lower Peninsula of locales of the Holland area, more permeable sand lenses are Michigan. The western portion of the county borders the Lake present, but often these yield mineralized water. Lower perme‑ Michigan shoreline. Black‑Macatawa, Kalamazoo, Lower ability till is considered a confining layer in some areas. Sand Grand, Pere Marquette‑White, and Lake Michigan water‑ dunes are present along the western portion of the county, sheds drain Ottawa County. According to the February 2005 bordering Lake Michigan (Deutsch and others, 1958; Farrand Wellogic database, approximately 62 percent of the wells in and Bell, 1982). Sand dunes usually lie above the water table Ottawa County are completed in the glacial deposits, and 31 and may provide areas of recharge (Deutsch and others, 1958). percent in the bedrock units. There is insufficient informa‑ Bedrock underlies the glacial deposits. The bedrock sur‑ tion to make this distinction for 7 percent of the wells in the face in Ottawa County includes, from northeast to southwest, county. the Michigan Formation, Marshall Sandstone, and Coldwater Aquifers in the glacial deposits consist largely of sands Shale. The Michigan Formation consists of layers of sand‑ and gravels, and vary regionally in thickness and permeability. stone, siltstone, anhydrite or gypsum, dolomite, limestone, With the available information, glacial lithologies cannot be and shale. The lower permeability lithologies of the Michigan regionally correlated in the subsurface. This is likely due to Formation are considered a confining unit. The thickness of the lateral and vertical heterogeneity of glacial deposits that the Michigan confining unit ranges from less than 50 to 400 ft resulted from a complex depositional history (Westjohn and within the State (Westjohn and Weaver, 1998). others, 1994). The thickness of glacial deposits in Ottawa The Marshall Sandstone underlies the Michigan For‑ County ranges from less than 100 to greater than 400 ft thick mation. The Marshall Sandstone consists of one or more (Vanlier, 1968). Lacustrine deposits, outwash, till, and dune stratigraphically continuous permeable sandstones. The upper sand comprise the surficial deposits in the county (Deutsch sandstone is a quartzarenite to sublitharenite that is referred to and others, 1958; Vanlier, 1968; Farrand and Bell, 1982). as the Napoleon Sandstone Member. A shale, siltstone, and/or Lacustrine deposits are concentrated in the western and central carbonate layer separates the Napoleon Sandstone Member portions of the county, and consist primarily of lacustrine from the underlying lower Marshall sandstone. The lower sand and gravel (Farrand and Bell, 1982). In the Holland area, Marshall sandstone is comprised of two units. The upper unit lacustrine deposits are either clay‑rich or sand‑rich deposits. is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ The clay lacustrine deposits may act as a confining layer. The enite to sublitharenite. At the base of the Marshall Sandstone sandy lacustrine deposits and shallow outwash are considered is a fine‑ to medium‑grained litharenite that ranges in thick‑ one aquifer in the Holland area, because these deposits are ness from 30 to 125 ft. Permeable sandstones in the Marshall interbedded and hard to distinguish from each other (Deutsch Sandstone comprise the Marshall aquifer. The Marshall aqui‑ and others, 1958). According to the Public Water Supply data‑ fer ranges in thickness from 75 to greater than 200 ft within base, the estimated transmissivity for glacial wells ranges from the State (Westjohn and Weaver, 1998). In the northeastern approximately 3,740 to 45,985 ft2/day. portion of the Holland area, the Marshall Sandstone underlies The sand and gravel outwash is the most important the glacial deposits and yields fresh water. The Marshall Sand‑ water‑yielding deposit. Glacial outwash occurs primarily in stone is mostly eroded and only the lower Marshall sandstone the eastern portion of the county. However, shallow and buried is present in the Holland area. Here, the Marshall Sandstone outwash is present in the Holland area. The shallow outwash ranges in thickness from 0 to 58 ft (Deutsch and others, 1958). deposits contain some gravel, but are primarily fine to coarse Thus, in the Holland area, the Marshall aquifer cannot supply sand. Domestic and industrial wells obtain water from the large amounts of water, because it is too thin (Deutsch and shallow outwash. In the Holland area, buried outwash occurs others, 1958). However, in other areas of the county, the Mar‑ County Summaries 1 shall aquifer is capable of supplying water. According to the and Detroit River Group (Milstein, 1987). According to the Public Water Supply database, the estimated transmissivity for Public Water Supply database, the estimated transmissivity glacial wells ranges from approximately 615 to 1,070 ft2/day. for limestone bedrock wells ranges from approximately 610 to In Ottawa County, the southern portion of the county may 2,040 ft2/day. obtain freshwater, while the northern portion of the county The Traverse Group forms the majority of the bed‑ may obtain saline water from the Marshall aquifer (Westjohn rock surface in southern and central portion of Presque Isle and Weaver, 1996c). County. The Traverse Group primarily consists of fossiliferous The Coldwater Shale is generally considered a confin‑ limestone. In some areas the Traverse Group has been highly ing unit within the State, and ranges in thickness from 500 to fractured which leads to local areas of very high permeability 1,300 ft thick The Coldwater Shale consists of shale, sand‑ within that unit. In the western portion of the basin, porous stone, siltstone, and carbonates. More sandstone beds are dolomite and anhydrite may be present. In the eastern portion present in the Coldwater Shale in the eastern part of the State of the basin, interlayers of shale are common (Gardner, 1974). (Westjohn and Weaver, 1998). In Ottawa County, fractured The basal formation of the Traverse Group is the Bell Shale. portions of the carbonates in the Coldwater Shale may yield Bell Shale has a maximum thickness of 80 ft (Catacosinos water. However, the water is highly mineralized and is not and others, 2001). Several bedrock wells occur in the southern suitable for several uses. In the Holland area, the mineral‑ portion of the county, where the Traverse Group forms the ized water from the Coldwater Shale has migrated upward in bedrock surface. areas where heavy pumping of overlying aquifers takes place The Dundee Limestone underlies the Traverse Group. (Deutsch and others, 1958). Gardner (1974) divided the Dundee Limestone into the Roger City Member and underlying Reed City Member. The Rog‑ ers City Member is composed of dolomitized limestone in Presque Isle County the western portion of the State and impermeable limestone in the eastern portion of the State. The Reed City member is Presque Isle County is in the northeastern portion of the composed of porous dolomite underlain by anhydrite. The Lower Peninsula of Michigan. Lone Lake‑Ocqueoc, Black, anhydrite is absent in the eastern portion of the State (Gard‑ Thunder Bay, and Lake Huron watersheds are the surface ner, 1974). Where the Dundee Limestone forms the bedrock water drainages in the county. Lake Huron borders the surface, bedrock wells in this aquifer are generally located in northern and eastern portions of the county. According to the the north‑central and eastern portions of the county. February 2005 Wellogic database, approximately 38 percent of In Presque Isle County, the Detroit River Group forms the wells in Presque Isle County are completed in the glacial the bedrock surface in the northwestern portion of the county. deposits, and 50 percent in the bedrock units. There is insuffi‑ In the subsurface, the Detroit River Group consists of the cient information to make this distinction for 12 percent of the Lucas Formation, Amherstburg Formation, and Sylvania wells in the county. Sandstone. The Lucas Formation is primarily composed of In the Michigan Basin, glacial aquifers consist of sand interlayered carbonates and evaporites. Carbonate‑cemented, and gravel that are part of a thick sequence of Pleistocene fine‑ to medium‑grained, sandstone lenses are scattered near glacial deposits. With the available information, glacial the basal portion of the Lucas Formation. In the northern por‑ lithologies cannot be regionally correlated in the subsurface. tion of Presque Isle County, dolomite is more abundant in the This is likely due to the lateral and vertical heterogeneity of Lucas Formation, while in the remaining portion of the county, glacial deposits that resulted from a complex depositional his‑ limestone is the main constituent. The Lucas Formation is tory (Westjohn and others, 1994). The glacial deposits range up to 1,050 ft in thickness in the Michigan Basin. In some in thickness from 0 to 600 ft in Presque Isle County (Western areas, the water from this formation is brine and may contain Michigan University, 1981). The glacial deposits consist of hydrogen sulfide. The Amherstburg Formation underlies the till, outwash, and lacustrine deposits. Till plains composed of Lucas Formation. The Amherstburg Formation is up to 300 coarse‑textured till is abundant on the surface on areas of the ft thick and is composed of fossiliferous limestone that is southwestern and central portion of the county. The till plains dolomitized in some areas. An upper sandstone is present in contain several drumlins. Outwash, composed of sand and the formation in the western portion of the Michigan Basin. gravel, is also located in the southern portion of the county. The Sylvania Sandstone underlies the Amherstburg Formation Eskers are also located in the central portion of the county. and is approximately 300 ft thick. The Sylvania Sandstone is Sand and gravel lacustrine deposits are present on the surface composed of fine‑ to medium‑grained sandstone with quartz along the northern and eastern portions of the county, roughly overgrowths interlayered with carbonate (Gardner, 1974). The following the shoreline. Sand dunes are also present along the Sylvania Sandstone does not form part of the bedrock surface shoreline. An area of peat and muck is present in the southern in Presque Isle County (Milstein, 1987). In the northwestern portion of the county (Farrand and Bell, 1982). portion of the county, bedrock wells are generally located Bedrock underlies the glacial deposits. The bedrock along the Lake Huron shoreline where the Detroit River Group surface of Presque Isle County, from south to north, is com‑ forms the bedrock surface. posed of the Devonian Traverse Group, Dundee Limestone,  Summary of Hydrogeologic Conditions by County for the State of Michigan

There are several karst features that occur throughout Saginaw County glacial deposits are up to 600 ft thick (Handy, the county. The karst features are a result of dissolution of the 1982). The near‑surface glacial deposits in Saginaw County carbonate and evaporite bedrock units and subsequent collapse are dominated by basal‑lodgement till. The basal‑lodgment of these units. Kimmel (1983) considered Rainy Lake, Sunken till is generally greater than 50 ft thick, clay‑rich, and rela‑ Lake, and the intermittent lakes near Shoepac Lake to be karst, tively impermeable. Therefore, it acts as a confining layer to sinkhole‑controlled lakes. Long, Mindack, and Trapp Lakes the underlying glaciofluvial aquifer. The glaciofluvial aquifer are also considered karst, solution lakes (Kimmel, 1983). ranges in thickness from 0 to 130 ft and consists of sand and some gravel. The glaciofluvial aquifer is missing in areas, and basal lodgment till is in contact with the underlying bedrock. Roscommon County The hydraulic conductivity for the glaciofluvial aquifer based on aquifer tests ranges from 10 to 105 ft/day. The storage coef‑ Roscommon County is in the central‑northern portion of ficient for the glaciofluvial aquifer based on aquifer tests is 6.3 the Lower Peninsula of Michigan. The Muskegon, Au Sable, x 10‑4. The glacial aquifer yields both saline and fresh water. Au Gres‑Rifle, and Tittabawassee watersheds drain the county. (Hoard and Westjohn, 2001). According to the February 2005 Wellogic database, approxi‑ The Saginaw Formation underlies the glacial deposits mately 96 percent of the wells in Roscommon County are and consists of discontinuous interbeds of sandstone, siltstone, completed in the glacial deposits, and 0 percent in the bedrock shale, limestone, and coal. The sandstone of the Saginaw units. There is insufficient information to make this distinction Formation is what is referred to as the Saginaw aquifer. The for 4 percent of the wells in the county. Saginaw aquifer ranges in thickness from less than 100 to 370 In the Michigan Basin, glacial aquifers consist of sand ft within the State (Westjohn and Weaver, 1996a). According and gravel that are part of a thick sequence of Pleistocene gla‑ to the Public Water Supply database, the estimated transmis‑ cial deposits. With the available information, glacial litholo‑ sivity for wells completed in the Saginaw aquifer in Saginaw gies cannot be regionally correlated in the subsurface. This is County range from approximately 130 to 640 ft2/day. From a likely due to the lateral and vertical heterogeneity of glacial study in Lakefield, Jonesfield, Richland, and Fremont Town‑ deposits that resulted from a complex depositional history ships the Saginaw aquifer is approximately 100 to 300 ft (Westjohn and others, 1994). The glacial deposits in Roscom‑ thick. The hydraulic conductivity and storage coefficient for mon County consist primarily of outwash and ice‑contact the Saginaw aquifer based on an aquifer test in Lakefield outwash deposits. In the southeastern portion of the county, Township is 7.7 ft/day and 3.0 x 10‑4, respectively (Hoard and coarse‑ and fine‑grained till, and coarse‑grained lacustrine Westjohn, 2001). The Saginaw aquifer yields fresh water in deposits are present (Farrand and Bell, 1982). A glacial well this area. However, in other areas of the county it yields saline in the county, according to the Public Water Supply database, water. The Saginaw aquifer yields fresh water only in areas has an estimated transmissivity from an aquifer test that is along the western and southern edge of the county (Westjohn approximately 13,520 ft2/day. Bedrock underlies the glacial and Weaver, 1996c). The Saginaw confining unit underlies the deposits, but is not currently used for water supply. Saginaw aquifer. The Saginaw confining unit is approximately 50 to 100 ft thick in the county. It is primarily shale, with thin Saginaw County layers of discontinuous sandstone, siltstone, limestone, and coal. The permeable layers within the Saginaw confining unit Saginaw County is in the east‑central Lower Peninsula appear to be isolated from the regional ground‑water‑flow of Michigan, in an area termed the Saginaw Lowlands. The system (Westjohn and Weaver, 1996a). Kawkawlin‑Pine, Pigeon‑Wiscoggin, Tittabawassee, Shiawas‑ The Saginaw confining unit separates the Saginaw aqui‑ see, Flint, Cass, and Saginaw watersheds drain the county. fer from the underlying Parma‑Bayport aquifer. The Parma According to the February 2005 Wellogic database, approxi‑ Sandstone is often considered the basal unit of the Saginaw mately 53 percent of the wells in Saginaw County are com‑ Formation, although the stratigraphic relationship is not pleted in the glacial deposits, and 43 percent in the bedrock clear between the Saginaw Formation, Parma Sandstone, and units. There is insufficient information to make this distinction Mississippian‑aged Bayport Limestone. The Parma Sandstone for 4 percent of the wells in the county. Sandstones from the is composed of medium‑ to coarse‑grained sandstone, and Saginaw Formation comprise the main bedrock aquifer in the is generally less than 100 ft thick (Cohee and others, 1951). county. In areas of Saginaw County, both bedrock and glacial The Bayport Limestone is a fossiliferous, cherty limestone, aquifers supply saline water (Hoard and Westjohn, 2001). often with interbedded sandstone and varies considerably in In the Michigan Basin, glacial aquifers consist of sand thickness from one area to another. The Bayport Limestone and gravel that are part of a thick sequence of Pleistocene and Parma Sandstone appear to interfinger throughout the glacial deposits. With the available information, glacial Michigan Basin. These units are hydraulically connected, and lithologies cannot be regionally correlated in the subsurface. together they form the Parma‑Bayport aquifer (Westjohn and This is likely due to the lateral and vertical heterogeneity of Weaver, 1996a). The Parma‑Bayport aquifer is approximately glacial deposits that resulted from a complex depositional 100 to 150 ft thick within the Michigan Basin. Please note that history (Westjohn and others, 1994). Locally, in areas of due to the uncertainty of stratigraphic relationship between County Summaries  these units, in other reports this aquifer may be delineated dif‑ lithologies cannot be regionally correlated in the subsurface. ferently. The Parma‑Bayport aquifer may contain saline water This is likely due to the lateral and vertical heterogeneity of in Saginaw County (Westjohn and Weaver, 1996c). glacial deposits that resulted from a complex depositional Underlying the Bayport Limestone is Michigan Forma‑ history (Westjohn and others, 1994). The glacial deposits in tion. The Michigan Formation is composed of sandstone, Sanilac County range from 0 to 400 ft thick (Western Michi‑ shale, limestone, and occasional dolomite. Gypsum and gan University, 1981). Outwash, till, and lacustrine deposits anhydrite are also present in the Michigan Formation. The low are present in the county. Outwash, which is composed of sand permeability lithologies of the Michigan Formation make up a and gravel, is present predominately in the western portion of confining unit that separates the Parma‑Bayport aquifer from the county. In the county, fine‑ to coarse‑grained till is pres‑ the underlying Marshall aquifer. The Michigan confining unit ent in till plains and moraines. Both fine and coarse‑grained is approximately 50 to 400 ft thick within the State. (Westjohn lacustrine deposits also are present in the county (Farrand and and Weaver, 1996b). Bell, 1982). Black River basin is a part of the St. Clair water‑ The Marshall Sandstone underlies the Michigan Forma‑ shed. Soils in the Black Glacial deposits are less than 100 ft tion. The Marshall Sandstone consists of one or more strati‑ thick in the northern portion, while nearly 300 ft thick in the graphically continuous permeable sandstones. The upper central portion of the Black River basin. The northern and sandstone is a quartzarenite to sublitharenite that is referred to central portions of the Black River basin are located in Sanilac as the Napoleon Sandstone Member. A shale, siltstone, and/or County. The glacial deposits in this area are mainly composed carbonate layer separates the Napoleon Sandstone Member of lower permeability deposits, such as clay or a mix of clay, from the underlying lower Marshall sandstone. The lower sand, and gravel (Twenter, 1975). The specific capacity values Marshall sandstone is comprised of two units. The upper unit from the glacial deposits in the Black River basin in Sanilac is generally 50 to 125 ft of fine‑ to medium‑grained quartzar‑ County, according to Twenter (1975), range between 0.5 and enite to sublitharenite. At the base of the Marshall Sandstone 2.5 gal/min/ft. According to the Public Water Supply data‑ is a fine‑ to medium‑grained litharenite that ranges in thick‑ base, the estimated transmissivity for glacial wells in Sanilac ness from 30 to 125 ft. Permeable sandstones in the Marshall County ranges from approximately 3,660 to 108,680 ft2/day. Sandstone comprise the Marshall aquifer. The Marshall aqui‑ Generally, the water from the glacial wells is hard and high fer ranges in thickness from 75 to greater than 200 ft within in dissolved solid concentrations, sulfate, and iron (Twenter, the State (Westjohn and Weaver, 1998). The Marshall aquifer 1975). Haack and Rachol (2000a) found water from some yields both brine and saline water in Saginaw County (West‑ glacial wells in Sanilac County to have arsenic concentrations john and Weaver, 1996c). that exceed the 2006 USEPA maximum contaminant level of The Coldwater Shale underlies the Marshall Sandstone. 10 µg/L. The Coldwater Shale consists of shale, sandstone, siltstone, The bedrock surface in the county is composed of the and carbonates. This is considered a confining unit and ranges Michigan Formation, Marshall Sandstone, Coldwater Shale, in thickness, from east to west across the State, from 500 to Sunbury Shale, Berea Sandstone, Bedford Shale, and Ant‑ 1,300 ft thick. It is the bottom unit of the Michigan Basin rim Shale. The Marshall Sandstone and Coldwater Shale are regional aquifer system. The Coldwater shale does not contrib‑ the bedrock aquifers in the county. The Michigan Formation ute a significant amount ground water to the region (Westjohn consists of layers of sandstone, siltstone, anhydrite or gyp‑ and Weaver, 1998). sum, dolomite, limestone, and shale. The lower permeability lithologies of the Michigan Formation are considered a confin‑ ing unit. The thickness of the Michigan confining unit ranges Sanilac County from less than 50 to 400 ft within the State (Westjohn and Weaver, 1998). Sanilac County is in the east‑central Lower Peninsula The Marshall Sandstone underlies the Michigan Forma‑ of Michigan. Lake Huron borders the eastern side of Sanilac tion. The Marshall Sandstone is primarily composed of sand‑ County. Sanilac County contains the Cass (west), St. Clair stone and capable of large water yields. The Marshall Sand‑ (central), and Birch‑Willow (east) watersheds. The Black stone in this region consists of medium‑grained sandstone with River Basin is part of the St. Clair watershed. According to the shale and chert, underlain by a silty shale layer, and another February 2005 Wellogic database, approximately 38 percent of lower layer of fine to medium‑grained sandstone (Twenter, the wells in Sanilac County are completed in the glacial depos‑ 1975). According to the Public Water Supply database, the its, and 59 percent in the bedrock units. There is insufficient estimated transmissivity, from aquifer tests, for wells com‑ information to make this distinction for 3 percent of the wells pleted in the Marshall aquifer in Sanilac County range from in the county. Bedrock wells are more abundant on the western approximately 690 to 990 ft2/day. side of the county, while glacial wells are more abundant on Coldwater Shale underlies the Marshall Sandstone and the eastern side. consists of micaceous shale with siltstone, local beds of sand‑ In the Michigan Basin, glacial aquifers consist of sand stone, and another layer of shale with lenses of siltstone. The and gravel that are part of a thick sequence of Pleistocene sandstone in the Coldwater Shale is capable of supplying small glacial deposits. With the available information, glacial quantities of water. Specific capacity values from the bedrock  Summary of Hydrogeologic Conditions by County for the State of Michigan aquifers, the Marshall Sandstone and Coldwater Shale, in the This segment is poorly sorted, and produces small supplies Black River Basin of Sanilac County range between 0.3 and of water locally. Primarily sand‑rich till with areas of boul‑ 150 gal/min/ft. Generally, the water from the bedrock is hard der‑rich till comprises the Hiawatha and Stueben segments. (Twenter, 1975). Water from some Marshall Sandstone wells The Hiawatha segment produces moderate yields of water and in Sanilac County have arsenic concentrations that exceed the is approximately 200 ft thick. The same is expected for the 2006 USEPA maximum contaminant level of 10 µg/L (Haack Steuben segment, although no information is available. Part of and Rachol, 2000a). the Munising Moraine extends across the northern portion of Underlying the Coldwater Shale and forming the Schoolcraft County. This is primarily composed of sandy till bedrock surface in the southeastern portion of the county and is permeable. Outwash deposits are primarily composed are bedrock layers that are generally not used as aquifers in of sand and gravel. These are generally the most permeable Sanilac County. These units include the Sunbury Shale, Berea glacial deposit because they are composed of reasonably well Sandstone, Bedford Shale, and Antrim Shale. sorted, coarse‑grained material. Glacial outwash is located primarily in the northern portion of Schoolcraft County. Most of the lacustrine deposits in the county are sand, with some Schoolcraft County clay and silt that often underlie the sandy layers. In some areas of the county, the sandy lacustrine deposits are well sorted and Schoolcraft County is in the Upper Peninsula of Michi‑ may be a potential water source if thick enough. Lacustrine gan. The Betsy‑Chocolay, Tahquamenon, Fishdam‑Sturgeon, deposits are abundant in the central portion of the county. Manistique, Brevoort‑Millecoquins, and Lake Michigan Dune deposits in the county are moderately permeable and watersheds drain the county. According to the February 2005 consist of well‑sorted, fine‑grained sand particles. There are Wellogic database, approximately 31 percent of the wells in relatively few dune deposits but they can be found throughout Schoolcraft County are completed in the glacial deposits, and the county, and may provide areas of recharge (Sinclair, 1959). 65 percent in the bedrock units. There is insufficient infor‑ The bedrock aquifers underlie the glacial deposits, where mation to make this distinction for 4 percent of the wells in glacial deposits are present in the county. In the subsurface, the county. In general, water is more available from bedrock the bedrock units dip to the southeast and trend southwest to aquifers in the southern part of the county where glacial northeast on the bedrock surface. The oldest units form the deposits are thinnest. Glacial deposits overlie the bedrock bedrock surface in the northern portion of the county, and the and the glacial aquifer is generally unconfined throughout the youngest units in the southern portion. The estimated trans‑ county. However, in areas where lenses of clay are present in missivity for the bedrock aquifers range from 36 to 4,318 the glacial deposits, the aquifer may be locally semi‑confined ft2/day (Sinclair, 1959; Brannen, 1997). Some transmissivity or confined. The uppermost portion of the bedrock aquifer is values were calculated using specific capacity values (Sinclair, generally unconfined in the county. 1959). Aquifers in the glacial deposits consist largely of sands When all bedrock layers are present, such as in the south‑ and gravels, and vary regionally in thickness and permeability. ern portion of the county, the uppermost bedrock is composed The glacial deposits in Schoolcraft County are thickest in the of the Engadine and Manistique Dolomites. The Engadine northern part of the county and thin and discontinuous in the and Manistique Dolomites are composed primarily of dolo‑ southern portion. The northern part of the county primarily mite, with some chert nodules being found in the Manistique contains sand that will yield moderate supplies of water. The Dolomite. The Engadine Dolomite does not cover a large glacial deposits range in thickness from 0 to greater than 200 area and is thin in Schoolcraft County. Where the Manistique ft. The estimated transmissivity for the glacial aquifer ranges Dolomite is thick, it is an important water supply, especially between 416 and 571 ft2/day (Sinclair, 1959). The glacial near Lake Michigan. The Burnt Bluff Formation underlies deposits include moraines, outwash, and lacustrine deposits. Manistique Dolomite and is primarily composed of dolomite The moraine deposits are composed of glacial till, which is and limestone. In Schoolcraft County, the Burnt Bluff Forma‑ poorly sorted and varies in grain size. Generally, the till depos‑ tion supplies moderate supplies of water to highly populated its in areas of higher elevation in Schoolcraft County contain areas (Sinclair, 1959). The Cataract Formation underlies the predominately poorly sorted silt and clay. Whereas in areas Burnt Bluff Formation. The Cataract Formation consists of of lower elevation, till deposits have been reworked resulting dolomite with shale and gypsum. The poor water quality in the in increased sorting and removal of fine‑grained sediments. Cataract Formation is attributed to the dissolution of gypsum This in turn causes an increase in the deposits’ permeability. within this unit. The basal shale of the overlying Cataract For‑ The Cooks Moraine is located in the southwestern part of the mation, where present, may confine water within the underly‑ county. The Cooks Moraine is very poorly sorted and contains ing limestone and dolomite of the Richmond Group. In some a large amount of clay and silt rich till. Consequently this areas, especially where the Richmond Group does not form the unit has a low permeability. The Newberry Moraine extends bedrock surface, it supplies water with a high mineral content. discontinuously across the county from east to west, and has The lower portion of the Richmond Group and the Colling‑ been divided into the Blaney, Hiawatha, and Steuben seg‑ wood Formation form a shale layer that ranges in thickness ments. The Blaney segment is approximately 100 ft thick. from 200 to 260 ft. This layer may confine the limestone and County Summaries  dolomite of the underlying Trenton and Black River Forma‑ Weaver, 1998). Haack and Rachol (2000f) found the highest tions. In the southern portion of the county, the Trenton and arsenic concentrations in the county in the glacial wells. Black River Formations supply moderate amounts of water. Bedrock underlies the glacial deposits. The Grand River However, the water may be highly mineralized especially at Formation, Saginaw Formation, Parma Sandstone, Bayport depth in the aquifer. Below the Trenton and Black River For‑ Limestone, Michigan Formation, Marshall Sandstone, and mations is the Prairie du Chien Group. This unit is composed Coldwater Shale form the bedrock surface in the county. The of dolomite with lenses of sandstone and sandy‑shale. The Pennsylvanian‑aged bedrock forms the majority of the bed‑ Munising Formation underlies the Prairie du Chien Group. rock surface in the county, and includes the Grand River and The Munising Formation is comprised primarily of somewhat Saginaw Formations. The Grand River Formation is generally dolomitic sandstone with areas of shale. The Prairie du Chien 50 to 100 ft thick and is small in aerial extent within the State. Group and Munising Formation form the bedrock surface It is primarily composed of coarse‑grained sandstone with in the northern part of the county. These formations supply layers of shale, carbonate, and coal (Catacosinos and others, freshwater that becomes more mineralized toward the southern 2001). The Grand River Formation is difficult to differenti‑ portion of the county. Underlying the Munising Formation ate from the underlying Saginaw Formation (Westjohn and is Jacobsville Sandstone. The Jacobsville Sandstone is not a Weaver, 1996a). The Saginaw Formation contains interbeds of source of water in Schoolcraft County. Below this are meta‑ sandstone, siltstone, limestone, coal, and shale (Westjohn and morphic and igneous Precambrian rocks that are too deep and Weaver, 1998). The Saginaw Formation ranges in thickness impermeable to supply water in the county (Sinclair, 1959). from 100 to 400 ft, shallowing towards the southern end of the Shiawassee County (Michigan Water Resources Commission, 1963). The Parma Sandstone is often considered the basal Shiawassee County unit of the Saginaw Formation, although the stratigraphic relationship is not clear between the Saginaw Formation, Shiawassee County is in the south‑central Lower Pen‑ Parma Sandstone, and underlying Mississippian‑aged Bayport insula of Michigan. The Maple, Upper Grand, Flint, and Limestone. The Parma Sandstone is composed of medium‑ to Shiawassee watersheds cross the northwestern, southwest‑ coarse‑grained sandstone, and is generally less than 100 ft ern, northeastern, and central to southeastern portions of the thick (Cohee and others, 1951). county, respectively. According to the February 2005 Wellogic The Pennsylvanian bedrock above the Parma Sandstone database, approximately 36 percent of the wells in Shiawassee can be divided into an upper sandstone aquifer and a lower County are completed in the glacial deposits, and 59 percent confining unit. The Saginaw aquifer is in the sandstones from in the bedrock units. There is insufficient information to make the Grand River and Saginaw Formations. The Saginaw aqui‑ this distinction for 5 percent of the wells in the county. fer ranges in thickness from less than 100 to 370 ft within the In the Michigan Basin, glacial aquifers consist of sand State (Westjohn and Weaver, 1996a). According to the Public and gravel that are part of a thick sequence of Pleistocene Water Supply database, in Shiawassee County the Saginaw glacial deposits. With the available information, glacial aquifer has estimated transmissivities from aquifer tests that lithologies cannot be regionally correlated in the subsurface. range from approximately 590 to 12,930 ft2/day. In most of This is likely due to the lateral and vertical heterogeneity of Shiawassee County, the Saginaw aquifer yields fresh water; glacial deposits that resulted from a complex depositional however, in the eastern portion of the county, the aquifer yields history (Westjohn and others, 1994). In the Saginaw Low‑ saline water (Westjohn and Weaver, 1996c). The Saginaw con‑ lands, the glacial deposits are composed of mostly lacustrine fining unit underlies the Saginaw aquifer. The Saginaw confin‑ sediments and basal lodgment till (Westjohn and Weaver, ing unit is approximately 50 ft thick and is mostly shale, with 1998). In Shiawassee County, this area is north of Owosso, thin layers of discontinuous sandstone, siltstone, limestone, where a till plain has been covered with lacustrine deposits and coal. The permeable layers within the Saginaw confining composed of clay and fine‑grained sand (Michigan Water unit appear to be isolated from the regional ground‑water‑flow Resources Commission, 1963). Vertical hydraulic conductivity system (Westjohn and Weaver, 1996a). of the basal lodgment till ranges between 2.83 x 10‑4and 2.83 Bedrock of Mississippian age underlies the Saginaw x 10‑5 ft/day (Westjohn and Weaver, 1998). Glacial deposits in Formation. This includes the Bayport Limestone, Michi‑ the remaining portion of the county are composed of till and gan Formation, Marshall Formation and Coldwater Shale. outwash (Vanlier, 1968; Michigan Water Resources Commis‑ The Bayport Limestone is a fossiliferous, cherty limestone, sion, 1963). The glacial deposits range from approximately 0 often with interbedded sandstone and varies considerably in to 200 ft in thickness (Vanlier, 1968). Moraines and till plains thickness from one area to another. The Bayport Limestone are composed of medium‑ to coarse‑grained till. The outwash and Parma Sandstone appear to interfinger throughout the deposits consist of sand and gravel (Farrand and Bell, 1982). Michigan Basin. These units are hydraulically connected, and According to the Public Water Supply database, the estimated together they form the Parma‑Bayport aquifer (Westjohn and transmissivity of glacial wells in Shiawassee County ranges Weaver, 1996a). The Parma‑Bayport aquifer is approximately from approximately 220 to 200,535 ft2/day. Glacial deposits in 100 to 150 ft thick within the Michigan Basin. Please note that the Saginaw Lowlands may yield saline water (Westjohn and due to the uncertainty of stratigraphic relationship between  Summary of Hydrogeologic Conditions by County for the State of Michigan these units, in other reports this aquifer may be delineated dif‑ February 2005 Wellogic database, approximately 85 percent ferently. The Parma‑Bayport aquifer may yield saline water in of the wells in St. Clair County are completed in the glacial Shiawassee County (Westjohn and Weaver, 1996c). deposits, and 13 percent in the bedrock units. There is insuf‑ The Michigan Formation underlies the Bayport Lime‑ ficient information to make this distinction for 2 percent of the stone. The Michigan Formation consists of layers of sand‑ wells in the county. stone, siltstone, anhydrite or gypsum, dolomite, limestone, In the Michigan Basin, glacial aquifers consist of sand and shale. The lower permeability lithologies of the Michigan and gravel that are part of a thick sequence of Pleistocene Formation are considered a confining unit that separates the glacial deposits. With the available information, glacial Parma‑Bayport aquifer from the underlying Marshall aquifer. lithologies cannot be regionally correlated in the subsurface. The thickness of the Michigan confining unit ranges from This is likely due to the lateral and vertical heterogeneity of less than 50 to 400 ft within the State (Westjohn and Weaver, glacial deposits that resulted from a complex depositional 1998). history (Westjohn and others, 1994). The glacial deposits The Marshall Sandstone underlies the Michigan Forma‑ in St. Clair County range from 101 to 400 ft thick (Western tion. The Marshall Sandstone is composed of an upper quartz‑ Michigan University, 1981). Glacial deposits generally thicken arenite to sublitharenite that is referred to as the Napoleon in the interior of St. Clair County (Twenter, 1975). Glacial Sandstone Member. A shale, siltstone, and or carbonate layer deposits in the county include lacustrine deposits, till, and a separate the Napoleon Sandstone Member from the lower small amount of sand and gravel outwash (Knutilla, 1969a, Marshall sandstone. The lower Marshall sandstone is com‑ 1969b, 1970). Along the eastern side of the county, the glacial prised of two units. The upper unit is generally 50 to 125 ft of deposits are composed of silty‑clay till and lacustrine deposits fine‑ to medium‑grained quartzarenite to sublitharenite. At the with lenses of sand and gravel (Gillespie and Dumouchelle, base of the Marshall Sandstone is a fine‑ to medium‑grained 1989). Lacustrine deposits are primarily composed of silt and litharenite. This basal sandstone ranges in thickness from 30 clay, however, in a few areas the lacustrine deposits are com‑ to 125 ft. The permeable sandstone in the Marshall Sandstone posed of sand and gravel. Till in the county ranges from fine to is the Marshall aquifer. The Marshall aquifer is between 75 coarse grained (Farrand and Bell, 1982). and 200 ft thick within the State (Westjohn and Weaver, 1998). In certain areas of the county, more detailed informa‑ Shiawassee County is located somewhat in between Huron tion is available. In the Belle River basin, the soils are poorly County and Jackson County. The Marshall aquifer in Huron drained loam, silt loam, clay loam, and clay. In the Pine River County has transmissivity values between 7 to 50 ft2/day basin, in the central eastern part of the St. Clair County, these (Sweat, 1992). Transmissivity values in Jackson County are soils are high in lime and organic matter. There is approxi‑ between 7,500 and 29,000 ft2/day. In Shiawassee County, mately 75 ft of clay hardpan underlying the surface and in however, the Marshall aquifer yields saline water (Westjohn areas of the Belle River basin. In the Pine River basin, clay or and Weaver, 1996c). a mixture of clay, sand, and gravel is 60 to 150 ft thick. Below The Coldwater Shale consists of shale, sandstone, this, water supplies may be obtained from the glacial deposits. siltstone, and carbonates. This is considered to be a confin‑ In general, water from the glacial deposits may be mineralized ing unit and ranges in thickness, from east to west across the and hard. In the shallow glacial wells located in the Pine River state, from 500 to 1,300 ft. The Coldwater confining unit is basin, water is very hard, high in sulfate, and low in chloride. the bottom of the Michigan Basin regional aquifer system. With depth, glacial wells contain higher concentrations of The Coldwater Shale does not contribute a significant amount chloride, lower concentrations of sulfate, and are softer than ground water to the region (Westjohn and Weaver, 1996b). the shallow‑glacial wells. In the Black River basin, chloride concentrations may be high in water from the deep glacial deposits (Twenter, 1975). According to the Public Water Sup‑ St. Clair County ply database, the estimated transmissivity for glacial wells in the county ranges from approximately 1,780 to 2,705 ft2/day. St. Clair County is in the southeastern portion of the In areas of the county, the glacial deposit and bedrock Lower Peninsula of Michigan. The Birch‑Willow, Lake Huron, interface ranges in thickness from 5 to 20 ft. This interface Lake St. Clair, St. Clair, and Clinton watersheds drain the is composed of silty sand, gravel, and fractured bedrock northeastern most, northeastern, southeastern, northwestern (Gillespie and Dumouchelle, 1989). The bedrock surface is and central, and southern portions of the county, respectively. beneath the glacial deposits or glacial‑bedrock interface. The The St. Clair watershed consists of the Black River, Belle bedrock surface in St. Clair County includes the Michigan River, and Pine River basins. The Black River basin is in the Formation, Marshall Sandstone, Coldwater Shale, Sunbury north. The Belle River basin is just south of the Black River Shale, Berea Sandstone, Bedford Shale, and Antrim Shale basin, and between the Black River basin and the Belle River (Milstein, 1987; Twenter, 1975). basin, on the eastern side of the county, is the Pine River basin. The Michigan Formation consists of layers of sandstone, The Belle River basin is located along the central western siltstone, anhydrite or gypsum, dolomite, limestone, and shale. side of St. Clair County and extends in a thin strip, trending The lower permeability lithologies of the Michigan Formation southeast, to the eastern side of the county. According to the are considered a confining unit. The thickness of the Michigan County Summaries  confining unit ranges from less than 50 to 400 ft within areas The lower unit is fine‑grained, cemented, silty and/or shaly, of the State (Westjohn and Weaver, 1998). dolomitic sandstone that contains micas and pyrite in areas, The Marshall Sandstone underlies the Michigan For‑ but contains less pyrite and more shale (Ferris and others, mation. Within areas of the Michigan Basin, the Marshall 1954). Several wells in the eastern part of the Pine River Sandstone consists of one or more stratigraphically continuous basin obtain water from the Berea Sandstone (Twenter, 1975). permeable sandstones. The upper sandstone is a quartzarenite However, in nearby in Oakland County, saline water has been to sublitharenite that is referred to as the Napoleon Sandstone recorded in wells near 1,000 ft in depth that obtain water from Member. A shale, siltstone, and/or carbonate layer separates the Berea Sandstone (Mozola, 1954). The Bedford Shale the Napoleon Sandstone Member from the underlying lower underlies the Berea Sandstone. The Bedford Shale consists Marshall sandstone. The lower Marshall sandstone is com‑ of shale, sandy shale, and shaly limestone. The Antrim shale prised of two units. The upper unit is generally 50 to 125 ft of underlies the Bedford Shale. The Antrim Shale is composed of fine‑ to medium‑grained quartzarenite to sublitharenite. At the shale with concretions of pyrite and anthraconite. The Antrim base of the Marshall Sandstone is a fine‑ to medium‑grained Shale yields small water supplies locally in nearby Oakland litharenite that ranges in thickness from 30 to 125 ft. Perme‑ County. However, in Oakland County, the water is moderately able sandstones in the Marshall Sandstone comprise the Mar‑ to highly mineralized (Ferris and others, 1954). shall aquifer. The Marshall aquifer ranges in thickness from 75 to greater than 200 ft within the State (Westjohn and Weaver, 1998). The Marshall aquifer, in Huron County, has an esti‑ St. Joseph County mated transmissivity that ranges from 7 to 50 ft2/day (Sweat, St. Joseph County is in the southwestern Lower Penin‑ 1992). The estimated transmissivity in Jackson County is from sula of Michigan. The southern portion of the county borders 7,500 and 29,000 ft2/day (Westjohn and Weaver, 1998). St. Indiana. The county is in the St. Joseph watershed. According Clair County is located somewhat between these counties. The to the February 2005 Wellogic database, approximately 97 Marshall aquifer yields both saline and fresh water. In general, percent of the wells in St. Joseph County are completed in the salinity increases in water from the Marshall Sandstone with glacial deposits, and 2 percent in the bedrock units. There is depth and inward towards the center of the State (Westjohn insufficient information to make this distinction for 1 percent and Weaver, 1996c). In general, ground water from the Mar‑ of the wells in the county. shall Sandstone has a high concentration of dissolved solids With the available information, glacial lithologies cannot and high iron content (Twenter, 1975). be regionally correlated in the subsurface. This is likely due The Coldwater Shale consists of shale, sandstone, silt‑ to the lateral and vertical heterogeneity of glacial deposits that stone, and carbonates. Twenter (1975) indicated that in the resulted from a complex depositional history (Westjohn and Black River basin, in addition to the Marshall Sandstone, the others, 1994). Glacial deposits range from 51 to 400 ft thick in bedrock aquifers may include sandstone units from Coldwater the county (Western Michigan University, 1981). The glacial Shale. However, the Coldwater Shale is generally considered deposits in St. Joseph County are composed of outwash, and a confining unit. The Coldwater Shale ranges in thickness, till. Outwash covers most of the county and is composed of from east to west across the State, from 500 to 1,300 ft thick well‑sorted sand and gravel deposits (Farrand and Bell, 1982). (Westjohn and Weaver, 1996b). The Coldwater Shale contains A portion of the Prairie Ronde Fan is located in the northeast‑ more sandstone and siltstone in the eastern portion of the basin ern portion of Park Township in St. Joseph County. The Prairie and grades into more dolomitic deposits in the western portion Ronde Fan is a glaciofluvial fan composed of sand and gravel. of the basin (Monnett, 1948). Water from the Coldwater Shale Moraines comprised of medium to coarse till are present in the generally is low in iron content and low in dissolved solids county (Farrand and Bell, 1982). (Twenter, 1975). In the Michigan Basin, the glacial aquifer consists of The Sunbury Shale, Berea Sandstone, and Bedford Shale sand and gravel that is part of a thick sequence of Pleistocene form the bedrock surface east of the Coldwater Shale in St. glacial deposits (Westjohn and others, 1994). The Prairie Clair County. The Sunbury Shale underlies the Coldwater Ronde Fan overlies the regional glacial aquifer, and is laterally Shale. The Sunbury Shale is generally slightly calcareous hydraulically connected to other outwash deposits. A pumping shale with areas of pyrite. The Sunbury Shale yields little, if test was performed in a well located in Schoolcraft Township any, water that is mineralized with depth. The Berea Sand‑ in Kalamazoo County that is screened in the Prairie Ronde stone underlies the Sunbury Shale. The Berea Sandstone is Fan. This well location is just north of Park Township. The approximately 125 to 175 ft below the surface and often yields transmissivity of the fan was estimated to be 18,447 ft2/day at the only potable water that can be obtained from bedrock in this well location (Kehew and others, 1996). According to the the Pine River basin. In general, the Berea Sandstone con‑ Public Water Supply database, the estimated transmissivity for sists of two to three sandstones separated by shale. The upper outwash wells in the county ranges from approximately 360 unit is a fine‑grained, cemented silty and/or shaly, dolomitic to 17,470 ft2/day. Several wells in rural portions of the county sandstone that contains micas and pyrite in areas. The middle may be at risk for contamination from agricultural chemicals unit is more friable and consists of fine‑ to medium‑grained sandstone with beds of shale and well‑cemented sandstone.  Summary of Hydrogeologic Conditions by County for the State of Michigan due to the high permeability of the outwash deposits (Ervin be isolated from the regional ground‑water‑flow system (West‑ and Kittleson, 1988). john and Weaver, 1996a). The majority of the wells in the county are completed The Saginaw confining unit separates the Saginaw aqui‑ in the glacial deposits, however, a few wells are completed in fer from the underlying Parma‑Bayport aquifer. The Parma the underlying bedrock. The bedrock surface of the county Sandstone is often considered the basal unit of the Saginaw consists of the Coldwater Shale and, in the southwestern por‑ Formation, although the stratigraphic relationship is not tion of the county, the Ellsworth Shale (Milstein, 1987). The clear between the Saginaw Formation, Parma Sandstone, and Coldwater Shale consists of shale, sandstone, siltstone, and Mississippian‑aged Bayport Limestone. The Parma Sandstone carbonates. This is considered a confining unit and ranges is composed of medium‑ to coarse‑grained sandstone, and in thickness, from east to west across the State, between 500 is generally less than 100 ft thick (Cohee and others, 1951). and 1,300 ft thick. More sandstone beds are present in the The Bayport Limestone is a fossiliferous, cherty limestone, Coldwater Shale in the eastern part of the State (Monnett, often with interbedded sandstone and varies considerably in 1948). The Ellsworth Shale is composed of shale that ranges thickness from one area to another. The Bayport Limestone in thickness from 0 to 400 ft in the State (Western Michigan and Parma Sandstone appear to interfinger throughout the University, 1981). The Ellsworth Shale is composed of a gray Michigan Basin. These units are hydraulically connected, and to greenish‑gray shale, and generally contains some dolomite. together they form the Parma‑Bayport aquifer (Westjohn and The Ellsworth Shale may also be composed of sandstone and Weaver, 1996a). The Parma‑Bayport aquifer is approximately siltstone layers (Matthews, 1993). 100 to 150 ft thick within the Michigan Basin. Please note that due to the uncertainty of stratigraphic relationship between these units, in other reports this aquifer may be delineated dif‑ Tuscola County ferently. The Parma‑Bayport aquifer may contain saline water in Tuscola County (Mandle and Westjohn, 1987). Tuscola County is in the Saginaw Lowlands in the The Michigan Formation underlies the Bayport Lime‑ east‑central portion of the Lower Peninsula of Michigan. The stone. The Michigan Formation is composed of sandstone, Pigeon‑Wiscoggin, Flint, Cass, Saginaw, and Lake Huron shale, limestone, and occasional dolomite. Gypsum and watersheds cross the county. The area has a shallow water anhydrite are present throughout the Michigan Formation but table and poor drainage. According to the February 2005 Wel‑ are more abundant in the lower portion of the formation and in logic database, approximately 8 percent of the wells in Tuscola the western part of the county (Mandle and Westjohn, 1987; County are completed in the glacial deposits, and 89 percent Sweat, 1992). Locally, wells in the Michigan Formation may in the bedrock units. There is insufficient information to make supply water; however, the Michigan Formation is generally this distinction for 3 percent of the wells in the county. considered to be a confining unit. Often water from the forma‑ The thickness of the glacial deposits ranges from 11 to tion is saline. Haack and Rachol (2000g) found the highest 400 ft (Western Michigan University, 1981). Glacial deposits arsenic concentrations in Tuscola County to occur in Elkhand include lacustrine, till, and outwash deposits. The lacustrine Township in wells completed in the Saginaw and Michigan deposits usually lie on the surface and are composed of clay. Formations. Below these, are local deposits of sand and gravel outwash that The Marshall Sandstone underlies the Michigan Forma‑ when thick enough, are capable of high yields. Beneath these, tion. In Tuscola County, the upper portion of the Marshall is poorly sorted glacial till. (Mandle and Westjohn, 1987). Sandstone is a micaceous, cemented sandstone. The lower The bedrock surface underlies the glacial deposits. In portion of the Marshall Sandstone contains sandstones that Tuscola County, the bedrock surface is comprised of the contain hematite and layers of shale‑rich sandstone that transi‑ Saginaw Formation, Bayport Limestone, Michigan Formation, tion into the Coldwater Shale (Mandle and Westjohn, 1987). and Coldwater Shale. The Saginaw Formation is primarily The Marshall aquifer is composed of the sandstones within the interbeds of shale and silty shale with some layers of siltstone, Marshall Sandstone that are permeable and continuous (West‑ fine‑grained sandstone, limestone, and coal (Sweat, 1992; john and Weaver, 1996b). Water from the Marshall Sandstone Mandle and Westjohn, 1987). The upper sandstone units are is saline in the majority of Tuscola County (Westjohn and referred to as the Saginaw aquifer. The Saginaw aquifer ranges Weaver, 1996c). in thickness from less than 100 to 370 ft within the State The Coldwater Shale underlies the Marshall Sandstone. (Westjohn and Weaver, 1996a). In Tuscola County, the Sagi‑ The Coldwater Shale is considered to be a confining unit naw aquifer yields saline water in the western portion of the within the State, and consists of mostly shale. Within the State, county, except for an area in the southwest, where the aquifer areas of siltstone, sandstone, dolomite, and limestone are also yields fresh water. The Saginaw confining unit underlies the included in the Coldwater confining unit. In general, the Cold‑ Saginaw aquifer. The Saginaw confining unit is approximately water confining unit does not yield water supplies (Westjohn 50 ft thick in the county. It is primarily shale, with thin layers and Weaver, 1996b). of discontinuous sandstone, siltstone, limestone, and coal. The permeable layers within the Saginaw confining unit appear to County Summaries 

Van Buren County from approximately 5,220 to 10,360 ft2/day. Till plains are dispersed throughout the county, and three morainic systems Van Buren County is along the shore of Lake Michi‑ are present: the Kalamazoo, Valparaiso, and Lake Border gan in the southwestern portion of the Lower Peninsula. In Moraines. The Kalamazoo Moraine is located in the southern addition to Lake Michigan, the county is drained by the St. part of the county, and consists of three ridges connected with Joseph, Black‑Macatawa, and Kalamazoo watersheds. The cross ridges. The area in between the ridges of the moraine glacial aquifer is the primary source of ground water. Accord‑ is covered with outwash. The Kalamazoo Moraine is com‑ ing to the February 2005 Wellogic database, approximately prised predominately of sand and gravel, often covered with 98 percent of the wells in Van Buren County are completed boulder‑rich, clay till, and underlain with areas of clay‑rich in the glacial deposits, and less than 1 percent in the bedrock till. The Valparaiso Moraine covers the majority of the county. units. There is insufficient information to make this distinc‑ It is a single broad moraine trending from the south, and tion for 2 percent of the wells in the county. In general, the extends into three ridges in the north. The Valparaiso Moraine glacial aquifer is unconfined except where clay‑rich, glaciola‑ is predominately sand and gravel with areas of silt and clay. custrine deposits act as a confining layer. The thickness of the Boulders are also present in the moraine. The Lake Border glacial deposits varies within the county. Glacial deposits do Moraine parallels the shoreline of Lake Michigan a few miles not always correlate beneath the surface (Giroux and others, inland. Ridges in the moraine are composed of clayey till, 1964). Within the State, this is likely due to the lateral and with lenses of sand and gravel. Glacial lacustrine deposits are vertical heterogeneity of glacial deposits that resulted from present in the western and northwestern portions of the county a complex depositional history (Westjohn and others, 1994). (Terwillinger, 1954). Glacial lacustrine deposits are composed Post‑glacial deposits in Van Buren County consist of eolian of sand, silt, and clay. The glaciolacustrine deposits do not deposits, lacustrine deposits, and alluvium. Eolian depos‑ yield large amounts of water. Van Buren County tends to have its consist of primarily dune sand along the Lake Michigan hard to very hard ground water. The exception is in the north‑ shore (Cummings and others, 1984). Dunes provide areas of western portion of the county. Water from the glacial deposits recharge; however, most are located above the water table also has high concentrations of iron, chloride, and nitrate in (Giroux and others, 1964). Post‑glacial lacustrine deposits are certain areas of the county (Giroux and others, 1964). delineated from glaciolacustrine deposits by the presence of Bedrock underlies the glacial deposits. The bedrock shorelines on all sides and a large amount of organic mat‑ surface is composed of the Coldwater Shale. The Coldwater ter. Post‑glacial lacustrine deposits are present in Pine Grove Shale ranges between 300 to 600 ft thick in Van Buren County, Township and near the intersection of Waverly, Arlington, and is primarily composed of shale, along with some lime‑ and Colombia Townships. Alluvium is composed of sand and stone. The Coldwater Shale generally yields small quantities gravel and is limited in extent. Post‑glacial deposits are gener‑ of water that may be saline, generally from the limestone in ally hydraulically connected to the glacial deposits (Cum‑ the unit (Giroux and others, 1964). mings and others, 1984). In the Michigan Basin, the glacial aquifer consists of sand and gravel that is part of a thick sequence of Pleisto‑ Washtenaw County cene glacial deposits. With the available information, glacial Washtenaw County is in the southeastern portion of lithologies cannot be regionally correlated in the subsurface. the Lower Peninsula of Michigan. Economically important This is likely due to the lateral and vertical heterogeneity of resources in the county are related to the geology of the area. glacial deposits that resulted from a complex depositional Oil and gas deposits are present in the bedrock units of the history (Westjohn and others, 1994). In Van Buren County, the county due to a series of parallel anticlines that trend north‑ thickness of glacial deposits ranges from 100 to 600 ft thick west to southeast across Washtenaw County. Glacial sand (Giroux and others, 1964; Cummings and others, 1984). The and gravel deposits are also abundant in the county, and these glacial deposits are composed of outwash, till, and glaciola‑ deposits often are mined. The potential for clay and peat min‑ custrine deposits. Sand and gravel outwash supplies the largest ing is also present in the county. quantity of water to wells. A large deposit of outwash trends Five watersheds are included in Washtenaw County. southwest, near Keeler, and extends northeast near Lawrence. The Upper Grand, Huron, Detroit, Raisin, and Ottawa‑Stony The estimated transmissivity for the sand and gravel aquifer watersheds are located in the northwestern, northern, north‑ ranges from approximately 2,675 to 20,050 ft2/day. east, southwest and central, and southeast portion of the Till is composed of clay, silt, sand, and gravel in vari‑ county, respectively. According to the February 2005 Wellogic ous proportions. The yield from till deposits varies, but it database, approximately 86 percent of the wells in Washtenaw is generally less than the yield from outwash. Till deposits County are completed in the glacial deposits, and 11 percent generally occur in moraines and till plains (Giroux and oth‑ in the bedrock units. There is insufficient information to make ers, 1964). Giroux and others (1964) observed that glacial till this distinction for 3 percent of the wells in the county. Water has an estimated transmissivity near 133 ft2/day. According from the glacial wells may be hard and contain high amounts to the Public Water Supply database, the estimated transmis‑ of iron. The water quality of the bedrock aquifer varies, but sivity for wells completed in till in Van Buren County ranges 70 Summary of Hydrogeologic Conditions by County for the State of Michigan may have high chloride and dissolved solids concentrations. along the surface and increase in age from the northwest to the The majority of the wells in the county are completed in gla‑ southeast. The Mississippian bedrock units, from youngest to cial deposits. oldest, include the Michigan Formation, Marshall Sandstone, Soils and glacial deposits that have relatively high perme‑ Coldwater Shale, Sunbury Shale, Berea Sandstone, and Bed‑ ability occur in areas of the county. However, surrounding ford Shale (Twenter and others, 1976). The Michigan Forma‑ these areas are regions where the surface is less permeable till tion forms a very small discontinuous portion of the bedrock or clay (Fleck, 1980). With the available information, glacial surface in the northwestern part of the county. The Michigan lithologies cannot be regionally correlated in the subsurface. Formation is composed of shale that is limy and sandy in the This is likely due to the lateral and vertical heterogeneity of lower portion of the formation (Twenter and others, 1976). glacial deposits that resulted from a complex depositional The lower permeability lithologies of the Michigan Formation history (Westjohn and others, 1994). Glacial deposits range are considered a confining unit. The thickness of the Michigan in thickness from 50 to 400 ft in Washtenaw County. In confining unit ranges from less than 50 to 400 ft within the the northwestern portion and areas in the southeast, glacial State (Westjohn and Weaver, 1998). deposits are less than 100 ft thick. In the northeastern and The Marshall Sandstone underlies the Michigan Forma‑ central portion of Washtenaw County, the glacial deposits are tion. The Marshall Sandstone consists of one or more strati‑ commonly greater than 250 ft in thickness. Glacial deposits graphically continuous permeable sandstones. The upper are composed of till, outwash, and lacustrine deposits. In the sandstone is a quartzarenite to sublitharenite that is referred to county, till is fine to coarse grained, and is present in moraines as the Napoleon Sandstone Member. A shale, siltstone, and/or and till plains. Moraines are a combination of clay, silt, sand, carbonate layer separates the Napoleon Sandstone Member and gravel. Outwash is composed of mostly sand and gravel. from the underlying lower Marshall sandstone. The lower Moraines and outwash cover the majority of the county, except Marshall sandstone is comprised of two units. The upper unit in the southeastern portion where lacustrine dominate.. Lacus‑ is generally 50 to 125 ft of fine‑ to medium‑grained quartzare‑ trine are generally composed of a thin sand layer underlain by nite to sublitharenite. At the base of the Marshall Sandstone is clay and silt (Fleck, 1980). a fine‑ to medium‑grained litharenite that ranges in thickness Aquifers in the glacial deposits consist largely of sands from 30 to 125 ft. Permeable sandstones in the Marshall Sand‑ and gravels and vary regionally in thickness and perme‑ stone comprise the Marshall aquifer. The Marshall aquifer ability. The ability to obtain water from the glacial deposits ranges in thickness from 75 to greater than 200 ft within the varies with location within the county. Twenter and others State (Westjohn and Weaver, 1998). (1976) classified the glacial deposits of Washtenaw County The Marshall Sandstone is generally a productive aquifer as aquifer and nonaquifer materials. Aquifer materials consist (Fleck, 1980). The Marshall aquifer supplies fresh water in of deposits that are permeable. Nonaquifer materials have Washtenaw County (Westjohn and Weaver, 1996c). However, low permeability. Low permeability glacial deposits include in a well in Lyndon and a well in Sylvan Township, Haack and clay, hardpan, and heterogeneous fine‑grained deposits. In the Rachol (2000h), found the two highest arsenic concentrations northwest one and/or two aquifers are present in the glacial in ground water for the county. Both these wells were com‑ deposits. One aquifer is able to supply moderate to large yields pleted in Marshall Sandstone (Haack and Rachol, 2000h). of water, while in other areas a shallow aquifer also is present In the central portion of the county, the Coldwater Shale that supplies enough water for domestic use. A large portion forms the bedrock surface (Fleck, 1980). The Coldwater Shale of the glacial deposits in southwestern Washtenaw County is underlies the Marshall Sandstone and has very low permeabil‑ composed of aquifer materials and may yield large supplies of ity. The Coldwater Shale consists of shale, sandstone, silt‑ water. West and northwest of Ann Arbor, the aquifer materials stone, and carbonates. This is generally considered a confining are thick, but lenticular. These glacial deposits may be able to unit and ranges in thickness, from east to west across the State, yield moderate to large amounts of water, but heavy pumping from 500 to 1300 ft thick (Westjohn and Weaver, 1996b). The may deplete the water supply quickly. In the eastern portion Coldwater Shale contains more sandstone and siltstone in the of the county, aquifer materials occur in small lenses, and are eastern portion of the basin and grades into more dolomitic probably sufficient for domestic supplies (Twenter and others, deposits in the western portion of the basin (Monnett, 1948). 1976). It may therefore be difficult to obtain large quantities In general, the Coldwater Shale does yield supplies of water, of water in Northfield, Salem, Superior, and Saline Town‑ except for localized, thin lenses of sandstone that may yield ships; however, sufficient amounts of water may be available enough water for domestic uses (McGuinness and others, for domestic supplies (Borton, 1974). In Augusta Township, 1949). aquifer materials are scarce in the glacial deposits and even The Sunbury Shale, Berea Sandstone, and Bedford Shale domestic supplies are difficult to obtain. (Twenter and others, have not been differentiated at the bedrock surface and form 1976). the bedrock surface southeast of the Coldwater Shale. The Bedrock underlies the glacial deposits. The bedrock is Sunbury Shale underlies the Coldwater Shale (Fleck, 1980). composed of Mississippian and Devonian sedimentary rocks, The Sunbury Shale has very low permeability and does not which generally dip to the northwest. The units of that form yield adequate supplies of water (McGuinness and others, the bedrock surface generally trend southwest to northeast 1949). However, according to Fleck, sandy lenses may provide County Summaries 1 water supplies (1980). The Berea Sandstone underlies the in the bedrock units. There is insufficient information to make Sunbury Shale and may provide water for domestic supplies in this distinction for 6 percent of the wells in the county. some areas (Fleck, 1980). However, in some areas the Berea The uppermost potential aquifer material is alluvium. Sandstone yields saline water (McGuinness and others, 1949). Alluvium ranges from 0 to 75 ft in thickness in areas of Wayne The Bedford Shale underlies the Berea Sandstone and except County. These deposits consist of clay, silt, sand, and gravel. for sandy lenses is impermeable (Fleck, 1980). Water obtained from wells that tap alluvium may be hard, but The Devonian units that form the bedrock surface of the quality is generally good. Washtenaw County consist of the Antrim Shale, Traverse Glacial deposits underlie the alluvium in the county, if Group, Dundee Limestone, and Detroit River Group. The alluvium is present. In the Michigan Basin, glacial aquifers Antrim Shale underlies the Bedford Shale. The Antrim Shale consist of sand and gravel that are part of a thick sequence is relatively impermeable except for sand lenses (Fleck, 1980). of Pleistocene glacial deposits. With the available informa‑ McGuinness and others noted that the Antrim Shale supplies tion, glacial lithologies cannot be regionally correlated in moderately mineralized, soft water to Belleville municipal the subsurface. This is likely due to the lateral and vertical wells (1949). The Traverse Group consists of limestone and heterogeneity of glacial deposits that resulted from a complex shale that may provide water for domestic use and also sup‑ depositional history (Westjohn and others, 1994). Glacial plies oil and gas deposits. The Traverse Group may supply deposits range in thickness from 20 to 400 ft in Wayne County saline water (McGuinness and others, 1949). The Dundee (Mozola, 1969). Most of the county is covered in lacustrine Limestone underlies the Traverse Group and forms the bed‑ deposits. The lacustrine deposits are composed of primar‑ rock surface generally southeast of the Traverse Group in the ily clay and sand. Till, composed of clay, silt, sand, gravel, southeastern portion of the county. The Dundee Limestone and boulders, also is present in the county. Moraines and till is composed of limestone and dolomite and may provide plains range in thickness from 180 to 400 ft, and are primarily water for domestic supplies. Oil and gas are also found in the composed of glacial till. Isolated sand and gravel deposits may Dundee Formation. The Detroit River Group forms the bed‑ be interspersed within the till. Two moraines are present in rock surface in the southeastern most portion of the county and the northwest corner of the county. These moraines are named consists of limestone, dolomite and evaporates. Gas is found the Outer Defiance and the Inner Defiance. These moraines in the Detroit River Group and the Detroit River Group may trend northeast to southwest and are separated by an outwash yield water for domestic supplies. The Sylvania Sandstone is deposit. Outwash deposits are primarily composed of sand the basal portion of the Detroit River Group. This is sandstone and gravel. The water from outwash deposits may be hard that often yields saline water (Fleck, 1980). (Mozola, 1969). According to the Public Water Supply data‑ Silurian and older rocks do not subcrop in Washtenaw base, the estimated transmissivity for a glacial well in Wayne County, but are present beneath the surface. Those that will County is approximately 56,330 ft2/day. be mentioned are the Bass Islands Group, the Salina Group, Bedrock underlies the glacial deposits in Wayne County. and the Niagara Group. The Bass Islands Group underlies the The bedrock in Wayne County consists primarily of Missis‑ Sylvania Sandstone, and consists of dolomite. Water from sippian and Devonian aged units and includes (in descending wells tapping the Bass Islands Group may be mineralized and order) the Coldwater Shale, Sunbury Shale, Berea Sandstone, some areas contain hydrogen sulfide (McGuinness and others, Bedford Shale, Antrim Shale, Traverse Group, Dundee Lime‑ 1949). The Salina Group underlies the Bass Islands Group stone, and Detroit River Group. The bedrock units generally and is composed of limestone, dolomite, and evaporites. In the trend northeast to southwest, and dip to the northwest. The northern portion of the county, the Salina Group contains salt youngest bedrock units subcrop in the northwestern part of beds that up to 400 ft thick. The underlying Niagara Group the county and are successively older towards the southeastern consists of limestone and dolomite. The Niagara Group con‑ portion of the county (Mozola, 1969). Water from bedrock tains oil and gas (Fleck, 1980). wells may be mineralized in this region (Twenter and others, 1975). The Coldwater Shale is the youngest bedrock unit in Wayne County Wayne County. The Coldwater and Sunbury Shales form the bedrock surface in a small area along the eastern edge of Wayne County is in the southeastern portion of the Lower Wayne County (Mozola, 1969). The Coldwater Shale consists Peninsula of Michigan. Lake St. Clair, Detroit, and Huron of shale, sandstone, siltstone, and carbonates. This is con‑ watersheds drain the county. Lake St. Clair watershed crosses sidered to be a confining unit in most of the State and ranges the northeastern portion of the county, while the Detroit water‑ in thickness, from east to west, from 500 to 1,300 ft. The shed covers the majority of the county. The Huron watershed Coldwater Shale contains more sandstone and siltstone in the trends northwest to southeast, south of the Detroit watershed, eastern portion of the Michigan Basin and grades into more and the Ottawa‑Stony watershed crosses the southwestern dolomitic deposits in the western portion of the basin (Mon‑ corner of the county. According to the February 2005 Wellogic nett, 1948). However, in most of the State the Coldwater Shale database, approximately 67 percent of the wells in Wayne does not contribute a significant amount of ground water to County are completed in the glacial deposits, and 27 percent the region (Westjohn and Weaver, 1996b). The Sunbury Shale  Summary of Hydrogeologic Conditions by County for the State of Michigan underlies the Coldwater Shale. The Sunbury Shale is generally Wexford County slightly calcareous with areas of pyrite. The Sunbury Shale yields little if any water that is mineralized with depth. Wexford County is located in the northwestern portion The Berea Sandstone underlies the Sunbury Shale. The of the Lower Peninsula of Michigan. The Muskegon and Berea Sandstone consists of two to three sandstones sepa‑ Manistee watersheds drain Wexford County. According to the rated by shale. The upper unit is fine‑grained, cemented, silty February 2005 Wellogic database, approximately 98 percent and/ or shaly, dolomitic sandstone that contains micas and of the wells in Wexford County are completed in the glacial pyrite in areas. The middle unit is more friable and consists deposits, and less than 1 percent in the bedrock units. There is of fine‑ to medium‑grained sandstone with beds of shale and insufficient information to make this distinction for 2 percent well‑cemented sandstone. The lower unit is a fine‑grained, of the wells in the county. cemented silty and/ or shaly, dolomitic sandstone that contains With the available information, glacial lithologies cannot micas and pyrite in areas, but contains less pyrite and more be regionally correlated in the subsurface. This is likely due shale (Ferris and others, 1954). In the region where the Berea to the lateral and vertical heterogeneity of glacial deposits that Sandstone forms the bedrock surface, yields from these wells resulted from a complex depositional history (Westjohn and are generally adequate for domestic use (Twenter and others, others, 1994). The glacial deposits in Wexford County range in 1975). However, saline water has been recorded in wells tap‑ thickness from 201 to greater than 1,000 ft (Western Michigan ping the Berea Sandstone in Oakland County near 1,000 ft in University, 1981). The glacial deposits in Wexford County depth (Mozola, 1954). The Bedford Shale underlies the Berea consist of outwash, till, and lacustrine deposits (Stewart, 1948; Sandstone. The Bedford Shale consists of shale, sandy shale, Farrand and Bell, 1982). Outwash deposits are abundant in and shaly limestone (Ferris and others, 1954). The Bedford the county and are generally underlain by well‑jointed clayey Shale does not yield much, if any, water to wells. till. Till occurs in till plains and moraines. The Lake Border The Antrim Shale underlies the Bedford Shale. The Ant‑ Moraine covers the largest area in Wexford County. In the rim Shale is composed of shale with concretions of pyrite and southeastern portion of the county, the Valparaiso and Char‑ possibly anthraconite and marcasite are present in the Antrim lotte Moraines are present. These are part of the Lake Michi‑ Shale (Ferris and others, 1954; Nicholas and others, 1996). gan‑Saginaw Interlobate tract. The Port Huron Moraine covers The Traverse Group comformably underlies the Antrim Shale. a small area in the north‑central portion of the county. The till Pyrite is present throughout the Traverse Group, which con‑ within the moraines contains abundant boulders, sand, and sists of beds of shale, limestone, and dolomite. The Dundee silt near the surface (Stewart, 1948). This till is classified as Limestone unconformably underlies the Traverse Group. Inter‑ coarse‑textured (Farrand and Bell, 1982). Underlying the till is bedded limestone and dolomite compose the Dundee Lime‑ an older clayey till (Stewart, 1948). Sand and gravel lacustrine stone. The limestone contains small vugs and the dolomite deposits are present on the surface in the southeastern portion contains vugs and fractures. Celestite and calcite are minerals of the county, near Cadillac (Farrand and Bell, 1982). Sand that are present in the vugs. Sulfur was found to occur in the dunes are common on the surface of glacial features through‑ fractures at shallow depths in areas of nearby Monroe County out the county (Stewart, 1948). (Nicholas and others, 1996). Glacial aquifers consist of sand and gravel that are part of The Detroit River Group unconformably underlies the a thick sequence of Pleistocene glacial deposits (Westjohn and Dundee Limestone. Sinkholes from this formation are pres‑ others, 1994). These sand‑and‑gravel aquifers supply water ent in Monroe County. Interbedded limestone and dolomite to the City of Cadillac and other users in Wexford County compose the upper Detroit River Group. The limestone con‑ (Baltusis and others, 1992). Exploratory drilling indicated tains small vugs and the dolomite contains vugs and fractures. three sand‑and‑gravel aquifers in the Cadillac area. Clay‑con‑ Celestite and calcite are minerals that are present in the vugs. fining units separate the aquifers (Hoard and Westjohn, 2005). Sulfur occurs in the fractures at shallow depths in this unit in Based on aquifer test results for the City of Cadillac, the deep Monroe County. The Sylvania Sandstone is the basal portion aquifer, which is over 265 feet below the ground surface, of the Detroit River Group and is a calcite cemented, moder‑ has a hydraulic conductivity of 214 ft/day (Jones, Henry and ately to well sorted, quartz sandstone. Pyrite, celestite, calcite, Williams Consulting Engineers, 1959), J.L. Wilcox & Associ‑ and sulfur are present in areas of the sandstone (Nicholas and ates (1986) conducted aquifer tests for production wells in others, 1996). The Sylvania Sandstone is the oldest bedrock Haring Township, which is just north of the City of Cadillac. unit that subcrops in Wayne County (Mozola, 1969). In the These tests indicate that the deep aquifer underlying Haring region where it forms the bedrock surface, yields from the Township has similar hydraulic properties to the deep aquifer Sylvania Sandstone wells are generally sufficient for domestic underlying Cadillac. Results from other aquifer tests within use (Twenter and others, 1975). the Cadillac area indicate horizontal hydraulic conductivities ranging from 43 to 163 ft/d for the shallow and intermediate aquifers in the glacial deposits and a vertical hydraulic con‑ ductivity of 0.031 ft/day for the clay‑confining unit between the intermediate and deep glacial aquifers (Hoard and West‑ john, 2005). According to the Public Water Supply database, References Cited  the estimated transmissivity, based on aquifer tests, for glacial as the Napoleon Sandstone Member. A shale, siltstone, and/or wells ranges from approximately 2,265 to 51,895 ft2/day. carbonate layer separates the Napoleon Sandstone Member Bedrock underlies the glacial deposits. The bedrock from the underlying lower Marshall sandstone. The lower surface of Wexford County is composed of the Saginaw For‑ Marshall sandstone is comprised of two units. The upper unit mation, Bayport Limestone, Michigan Formation, Marshall is generally 50 to 125 ft of fine‑ to medium‑grained quartzare‑ Sandstone, and Coldwater Shale (Milstein, 1987). The Sagi‑ nite to sublitharenite. At the base of the Marshall Sandstone is naw Formation forms the bedrock surface in the southeastern a fine‑ to medium‑grained litharenite that ranges in thickness portion of Wexford County, and is composed of interbedded from 30 to 125 ft. Permeable sandstones in the Marshall Sand‑ sandstone, siltstone, shale, coal, and limestone. The Saginaw stone comprise the Marshall aquifer. The Marshall aquifer aquifer consists of hydraulically connected sandstones in the ranges in thickness from 75 to greater than 200 ft within the Saginaw Formation (Westjohn and Weaver, 1996a). Within State (Westjohn and Weaver, 1998). The Marshall Sandstone the State, the Saginaw aquifer ranges less than 100 to 370 ft contains fresh and saline water, as well as, brine in Wexford thick, and yields fresh and saline water in areas of the State. County (Westjohn and Weaver, 1996c). The Saginaw aquifer contains fresh water in Wexford County The Coldwater Shale underlies the Marshall Sandstone. (Westjohn and Weaver, 1996c). The Saginaw confining unit The Coldwater Shale consists of primarily shale with interbeds underlies the Saginaw aquifer. The Saginaw confining unit is or lenses of sandstone, siltstone, and dolomite. The Coldwater approximately less than 100 to 240 ft thick within the State, Shale is relatively impermeable and is considered a confin‑ and is mostly shale, with thin layers of discontinuous sand‑ ing unit in most of Michigan (Westjohn and Weaver, 1996b). stone, siltstone, limestone, and coal. The permeable layers These bedrock units have not been used for water supply within the Saginaw confining unit appear to be isolated from because the overlying glacial deposits which consist predomi‑ the regional ground‑water‑flow system (Westjohn and Weaver, nantly of permeable sand and gravel provide enough water for 1996a). industrial, commercial, and domestic uses (Hoard and West‑ The Saginaw confining unit separates the Saginaw aqui‑ john, 2005). fer from the underlying Parma‑Bayport aquifer. The Parma Sandstone is often considered the basal unit of the Saginaw Formation, although the stratigraphic relationship is not clear between the Saginaw Formation, Parma Sandstone, and References Cited Mississippian‑aged Bayport Limestone. The Parma Sandstone is composed of medium‑ to coarse‑grained sandstone, and Aichele, S., Hill‑Rowley, R., and Malone, M., 1998, Arsenic, is generally less than 100 ft thick (Cohee and others, 1951). nitrate, and chloride in ground water, Oakland County, The Bayport Limestone is a fossiliferous, cherty limestone, Michigan: U.S. Geological Survey Fact Sheet 135‑98, 6 p. often with interbedded sandstone and varies considerably in thickness from one area to another. The Bayport Lime‑ Aichele, S. S., 2000, Ground‑water quality atlas of Oakland stone and Parma Sandstone appear to interfinger throughout County, Michigan.: U.S. Geological Survey Water‑Re‑ the Michigan Basin (Westjohn and Weaver, 1996a). These sources Investigations Report 00‑4120, 53 p. units are hydraulically connected, and together they form Allen, W. B., 1974, Flowing wells in Michigan: Michigan the Parma‑Bayport aquifer (Westjohn and Weaver, 1996a). Geological Survey Division Report W 2, 27 p. The Parma‑Bayport aquifer is approximately 100 to 150 ft thick within the Michigan Basin. Please note that due to the Allen, W. B., Miller, J. B., and Wood, W. W., 1972, Availabil‑ uncertainty of stratigraphic relationship between these units, ity of water in Kalamazoo County, southwestern Michigan: in other reports this aquifer may be delineated differently. U.S. Geological Survey Water‑Supply 1973, 129 p. The Parma‑Bayport aquifer contains fresh and saline water in Wexford County (Westjohn and Weaver, 1996c). Baltusis, M. A., Quigley, M. F., and Mandle, R. J., 1992, The Michigan Formation underlies the Bayport Lime‑ Municipal ground‑water development and withdrawals in stone. The Michigan Formation is composed of sandstone, the central Lower Peninsula of Michigan, 1870‑1987: U.S. shale, limestone, and occasional dolomite. Gypsum and anhy‑ Geological Survey Open‑File Report 91‑215, 89 p. drite are also present in the formation. The lower permeability Barton, G., 1995, Contributing areas of water‑supply wells in lithologies of the Michigan Formation are considered to be a Elkton and Pigeon, Huron County, MI: U.S. Geological Sur‑ confining unit that separates the Parma‑Bayport aquifer from vey Water‑Resources Investigations Report 94‑4089, 10 p. the underlying Marshall aquifer. The Michigan confining unit is approximately 50 to 400 ft thick in the State (Westjohn and Barton, G. J. and Grannemann, N. G., 1998, Water resources Weaver, 1996b). of Lac Vieux Desert Indian community and vicinity, west‑ The Marshall Sandstone underlies the Michigan For‑ ern Upper Peninsula, Michigan: U.S. Geological Survey mation. 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