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1 Hydrogeology Concepts and Exercise Brought to you by Core Kids, WMU-MGRRE MGRRE Geosciences K-12 Outreach Program With generous support from:

2 In this presentation and data-based exercise students will: Learn about a critical natural resource - water Learn about the science used by the professionals who manage our water resources. Learn about the subsurface geology of Michigan and that of their locale Learn to access public databases on natural resources compiled by the State of Michigan

3 Hydrogeology Concepts The water cycle or hydrologic cycle shows the continuous movement of water on, above, and db below the Earth s surface.

4 Hydrogeology Concepts Hydrology is the scientific study of the properties, distribution, and effects of water on the earth's surface, in the soil and underlying rocks, and in the atmosphere. Hydrogeologists g study the distribution and movement of water below the Earth's surface, especially the distribution of groundwater, it s flow, and groundwater quality.

5 Hydrogeologists & Hydrologists In Action

6 Hydrogeology Concepts Hydrogeologists need to understand what is under the ground surface in Michigan to know more about groundwater supplies here. Michigan is underlain by thousands of feet of bedrock, but most drinking water supplies are found in the uppermost few hundred feet. Geologic storage locations holding water are termed aquifers.

7 Glaciers Shaped Michigan s Surface Adapted from Charles Barker, 2005

8 Grand Canyon Rock Layer Thickness vs. Michigan Bedrock Thicknesses Layers of Rock of the Grand Canyon Layers of Rock Under Michigan Depth in Feet Below the Surface -0-1,000-2,000-3,000-4,000-5,000-6,000-7,000-8,000-9,000-10,000-11,000-12,000-13,000-14,000-15,000

9 Bedrock Layers Deposited Prior to Glaciation The bedrock of Michigan was deposited in a basin which h appears similar to as set of nested bowls. Modified from S. E. Wilson, 2006 Adapted from Olcott, 1992, and modified from Robinson, 2004

10 Hydrogeology Concepts Hydrogeologists study rocks and their properties to understand how water moves underground. These properties include: Consolidated vs. unconsolidated aquifer material Type and shape of the grains making up the aquifer How the material affects water flow Potential environments of deposition

11 Some Examples of Unconsolidated Sediments Medium Sand Pebbles/Gravel Coarse Sand Clay Very Fine Sand Fine Sand Silt

12 When unconsolidated sediments become lithified they are called Consolidated Sediments or Rocks Insert images from penn sandstones, etc. Sandstone Siltstone

13 Hydrogeology Concepts Porosity is the amount of space between the grains of sediment in unconsolidated or consolidated aquifer materials. The amount of pore space is determined by the shape, size, and sorting of the grains and any cements holding the grains together. The greater the pore space, the more porous the material is.

14 Sediment Grain Shape Analysis Tool From Jones & Jones, 2003 Grain roundness affects how sediments fit together when compacted or lithified. Sorting is a measure of the distribution of different sized sediments in a material. Poorly sorted sediments have grains of many different sizes present. Well-sorted sediments have grains of similar sizes. Larger grains may float in a matrix of smaller grains.

15 Hydrogeology Concepts When the pores of a material are connected together, water and other fluids can flow through the material. The more fluids that can pass through the pores, the more permeable a material is. Rocks are porous, but may not be considered permeable depending upon the characteristics of the pores and how they are connected.

16 Sediment: Sand Rock: Sandstone

17 Hydrogeology Concepts Water stored in the pores of unconsolidated and consolidated material is affected by gravity and pressure. The water table level at any location is an example of these effects. Pollution is a major threat to the relatively shallow nature of the water table and unconfined aquifers in many parts of Michigan.

18 Hydrogeologic Vocabulary: From Jones & Jones, 2002 Zone of aeration is where pores are filled mostly with air. Zone of saturation is where pores are filled with fluids. Water table is the boundary between the two zones.

19 Hydrogeology Concepts In Michigan, aquifers in unconsolidated, glacial sediments are termed unconfined aquifers. Easier to access, shallower More prone to pollution Bedrock aquifers are usually confined, or bounded by other rock units that do not allow as much or any water to pass. May be harder to access, but less easily polluted If too deep may be briny

20 Glacial Sediments and Bedrock Aquifers Modified from W. R. Farrand, 1982 Modified from the Institute of Water Research, 1987

From Jones & Jones, 2002 From Jones & Jones, 2002

Confined Aquifer Pumping wells affect the water

recharge in higher elevation areas can force

21 From Jones & Jones, 2002 From Jones & Jones, 2002 Unconfined Aquifer Hydrogeologic Vocabulary: Confined Aquifer Pumping wells affect the water in the pores of the aquifer surrounding them forming a cone of depression. In confined conditions, i water pressure from recharge in higher elevation areas can force wells to flow aboveground in lower-lying areas. These are called artesian wells or springs.

22 Hydrogeology Concepts Once hydrogeologists understand the aquifer material and the general geology of the area, they may assign an environment of deposition to the materials making up the aquifer. This understanding may give them clues about water quality, quantity, and availability.

Depositional Environment Affects Aquifers Example

The mudstones and siltstones may be barriers to water

23 Depositional Environment Affects Aquifers Example Deltaic deposits can be sandy or muddy and are home to many kinds of plants. Lithification turns sands to sandstone, and muds to mudstone and siltstone. The sandstones may be good water-bearing source rocks. The mudstones and siltstones may be barriers to water flow. Organic material trapped in the rocks from swampy areas may cause poor water quality from the release of gases from decayed vegetation.

24 Humans Contaminate Groundwater in Many Ways From Jones & Jones, 2003

25 Humans Contaminate Groundwater in Many Ways An illustration of salt-water encroachment, this can also occur in areas where deep bedrock aquifers are briny, like in Michigan s rock formations deposited from seas.

26 Exercise: Water Wells & Lithology Brought to you by Core Kids, WMU- MGRRE Geosciences K-12 Outreach Program Exercise created by Niah Venable, Amanda Walega and Susan Grammer with web content tb by Niah hv Venable A special thanks to 8 th grade teacher Becky Dalecki, Portage North Middle School and to the 8 th th grade science teachers and students t at Mattawan Middle School. With generous support from:

27 This exercise can be adapted for: High school students wishing to do an independent project using real data from their local area. Middle school students whose teachers can lead them through accessing data and constructing stratigraphic columns as a class according to the instructions on this website. Later elementary students who can use this exercise to visualize what is underground in their area.

28 Exercise Steps 1. Choose an area of interest (e.g. Charlotte, MI) 2. Find the corresponding topographic map 3. Find water well data from the area of interest 4. Interpret water well driller s logs 5C 5. Create lihl lithologic i columns 6. Calculate the Well Elevation 7. Create stratigraphic columns 8. Create cross-sections sections for comparison

29 1. Pick an Area of Interest For this example we will look at water wells around Charlotte, MI. Charlotte is located in Eaton County. First we need to get a topographic map of the area near Charlotte. This map will give us political and landform information such as section numbers and elevation contours for use in this project.

2. Find a Topo Map Browse to the State of Michigan, Department of

gov/dnr From there browse to Publications and Maps, then Online

Use the dropdown list to find the county, in this case it is

30 2. Find a Topo Map Browse to the State of Michigan, Department of Natural Resources homepage: From there browse to Publications and Maps, then Online Maps. Go to Topographic Quadrangles by Location. Use the dropdown list to find the county, in this case it is Eaton. A quick link to this page is: Click Download.

blue grid overlay of the quadrangle names.

31 2. Find a Topo Map cont. The next screen shows s a green and yellow version of a political map with the locations of cities and towns with a blue grid overlay of the quadrangle names. Click on the quad labeled Charlotte in Eaton and Carmel townships.

32 2. Find a Topo Map cont. A pdf of the Charlotte quadrangle will open in Adobe Acrobat. We can save this and use as-is or copy and zoom to a portion of the map using MS Word or image handling software.

3. Find Water Well Data Browse to the State of Michigan,

gov/deq ihi From there click Water, then browse to

then click on Scanned Water Well Record Retrieval System.

33 3. Find Water Well Data Browse to the State of Michigan, Department of Environmental Quality homepage: ihi From there click Water, then browse to Drinking Water, to Wt Water Well WllC Construction, ti then click on Scanned Water Well Record Retrieval System. A quick kli link to this page is: logs/

county, township and section data we need to search the well retrieval

We are interested in Eaton County so two searches need to be done by

34 3. Find Water Well Data cont. The information used to find the topo and the map itself provide the county, township and section data we need to search the well retrieval database. We are interested in Eaton County so two searches need to be done by township, one for Eaton in sections 6, 18 and d19 19; and one for Carmel in sections 12, 13, and 24. We will omit section 7 of Et Eaton township, due to an absence of usable logs.

35 3. Find Water Well Data cont. After selecting the county, township(s) and section(s) of interest, we will be able to review a pdf file containing the scanned images of driller s reports from each area. The pdf driller s reports or logs will look like this. The number of logs available for each section varies.

36 4. Interpreting Driller s Logs The driller s log header contains well location information and often a hand-drawn drawn map with street names, which may prove useful flifh the quarter-quarter location information is not recorded, or recorded incorrectly.

37 4. Interpreting Driller s Logs cont. The driller s log lithology information is listed by type of material, thickness of each unit, and total depth. The formation descriptions are more likely to be generic than scientific. The total drilled depth of this well is 100 feet bl below the surface.

38 4. Interpreting Driller s Logs cont. Other information provided by the driller s log is the owner of the well, the depth, the completion date and how the well was completed. It will also list possible sources of contamination, pump type, and who drilled the well. The static water level is equal to the depth to the water table, in this case it was encountered 36 feet below the surface.

39 5. Creating Lithologic Columns Lithologic i or stratigraphic columns can be created from driller s logs using the formation descriptions provided by the driller and the depths to and the thicknesses of each unit. From 0-12 feet below the surface the driller encountered clay. From 12 to 16 feet below the surface they found sand. From 16 to 54 feet below the surface they found clay. From 54 to 60 feet below was gravel. From 60 to 100 feet below the surface they found sandrock, most likely the sandstones of the Saginaw Aquifer.

40 5. Creating Lithologic Columns cont. A basic form created in Excel is useful for plotting lithogy and other well information for viewing as a lithologic or stratigraphic column. The lithologic key can be modified depending on the type of earth material encountered in the wells.

41 5. Creating Lithologic Columns cont. Using the driller s log Hammond depths below the surface as a guide, we plot the lithologic l i types on the column with the lithologic key yp patterns and colors as fill. Next, we mark the water level l on the column using the symbol from the key.

42 6. Calculate the Well Elevation To calculate the well elevation values in feet above sea level and to convert the lithogic column to a stratigraphic column, we must first determine the well surface elevation. This is done using a topographic map since most of the driller s r reports do not provide well elevations.

43 6. Calculate the Well Elevation cont. Using the topo map of Charlotte and the location information provided in the driller s report we find that t the example well is located here. Contour lines in this area range between 910 feet and 920 feet above sea level. Interpolating the location between the two contours gives us a value of 918 feet above sea level.

scale on the right side of the lithology column.

44 6. Calculate the Well Elevation cont. We record the well elevation in the blank to the right. And then place the value on the top line of fth the scale on the right side of the lithology column. Next we subtract the depths in ten foot increments e from the elevation value until the bottom of the well is reached.

45 7. Create Multiple Strat Columns To compare the hydrogeology from several wells around the Charlotte area we must create more stratigraphic columns. Repeat steps 3 through 6 to create these columns. For this example we will use driller s logsfrom Eaton township, sections 18 and 19, and Carmel township, sections 12, 13, and 24. We will mark the locations of all the wells on the topo map for reference.

46 7. Multiple Strat Columns cont. Hammond All of the wells are now marked on the topographic p map for reference. Well elevation values have been picked from the map and used to convert the lithologic columns to stratigraphic columns. Mishler Porter Burt Archer City

47 7. Multiple Strat Columns cont. Once the stratigraphic columns are created, a depth datum is picked. The depth datum is used to compare the lithology and water levels in all wells at corresponding depths. Well Name and Elevation Range: Hammond: ft. Burt: ft. City: ft. Archer: ft. Porter: ft. Mischler: ft. The depth datum should be 880 feet above sea level l since all wells intersect that depth.

48 8. Cross-Section Creation The geographic area covered by the wells can be divided into two cross-sectional sectional lines running approximately North to South They are labeled A to A and B to B. A B A B

49 8. Cross Section Creation cont. The wells in each cross-section section can be compared by lining them up on the datum value. 880 ft. A A ~ 1.5 mi. ~ 1 mi.

50 8. Cross Section Creation cont. It is important to remember the distances between wells when making cross-sectional sectional comparisons. 880 ft. B B ~ 1.75 mi. ~ 2 mi.

51 9. Interpretation The cross-sections sections combined with the well locations on the topo map give a spatial comparison of the earth materials encountered at depth and how those materials vary over a distance between wells. The wells are about 1 to 2 miles apart and the relief between the highest and lowest wells is 55 feet. Static water levels range between a max elevation just under 900 ft. to just over 875 ft.

52 9. Interpretation cont. The glacial sediments found above the sandstone and shale bedrock in this area show variation in type and thickness from well to well, which is typical of these kinds of materials. Generally though, the glacial deposits in the A- A wells consist of clay and gravels, while the deposits in the B-B B wells are mainly sand and clay.

53 9. Interpretation cont. The Charlotte wells show no significant variation in static water levels. Dramatic variations in static water levels could be due to draw down effects in heavy-use areas. The sandstone and shale bedrock elevations vary by 60 ft for all wells, but for each cross section, the variation is between feet.

54 10. Summary Topographic maps and water well driller s logs can be used to examine the near-surface geology of Michigan. The driller s logs are also useful for determining depth to the water table, potential nearby contamination i hazards, and other information. i The data needed for these exercises is readily available on the internet from State of Michigan sources.

Groundwater Hydrology

EXERCISE 12 Groundwater Hydrology INTRODUCTION Groundwater is an important component of the hydrologic cycle. It feeds lakes, rivers, wetlands, and reservoirs; it supplies water for domestic, municipal,