Hydrogeology CdiConcepts and Exercise Brought to you by Core Kids, WMUWMU--MGRREMGRRE Geosciences K -12 Outreach Program With generous support from: In this presentation and datadata--basedbased 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 andhd that of fhil their loca le Learn to access public databases on natural resources compiled by the State of Michigan Hydrogeology Concepts The water cycle or hyygdrologic cycle shows the continuous movement of water on, above, andbd be low the Earth’s surface. Hydrogeology Concepts Hydrology is the scientific study of the properties, distribution, and effects of water on the earth's surface, in the soil and underlyyging rocks, and in the atmosphere. Hyygdrogeolog ists study the distribution and movement of water below the Earth's surface, especially the distribution of groundwater, it’s flow, and ground water quali ty. Hydrogeologists & Hydrologists In Action 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 drinkinggpp water supplies are found in the uppermost few hundred feet. Geologic storage locations holding water are termed aquifers. Glaciers Shaped Michigan’s Surface Adapted from Charles Barker, 2005 Layers of Rock Layers of Rock Depth in Feet of the Grand Canyon Under Michigan Below the Surface Grand Canyon Rock -0 -1,000 Layer Thickness vs. - 2, 000 Michigan Bedrock - 3,000 - 4,000 Thicknesses -5,000 - 6,000 - 7,000 - 8,000 - 9,000 - 10,000 - 11,000 - 12,000 - 13,000 - 14,000 - 15,000 Bedrock Layers Deposited Prior to Glaciation The bedrock of Michigan was deposited ibihihin a basin which appears similar to as set of nested bowls . Adapted from Olcott, 1992 , and Modified from S. E. Wilson, 2006 modified from Robinson, 2004 Hydrogeology Concepts Hydrogeologists study rocks and their properties to understand how water moves underground. These properties include: Consolidated vs. unconsolidated aquifer material TdhfhikihifType and shape of the grains making up the aquifer How the material affects water flow Potential environments of deposition SESome Examp lfles of Unconsolidated Sediments Medium Sand Pebbles/Gravel Coarse Sand Clay Very Fine Sand Fine Sand Silt When unconsolidated sediments become lithified they are called Consolidated Sediments or Rocks IiInsert images from penn san dstones, etc. Sandstone Siltstone 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 t he pore space, t he more porous t he material is. Sediment Grain Shape Analysis Tool From Jones & Jones, 2003 Grain roundness affects how sediments fit together when compacted or lithifi ed . 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 gra ins may “float” i n a matrix of smaller grains. 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 depen ding upon t he c haracter ist ics o f t he pores and how they are connected. Sediment: Sand Rock: Sandstone 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 ofhf the water ta ble an d uncon fidfined aqu ifers i n many parts of Michigan. From Jones & Jones, 2002 Hydrogeologic Vocabulary: 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 . Hydrogeology Concepts In Michigan, aquifers in unconsolidated, glacial sediments are termed unconfined aquifers. Easier to access, shallower More prone to pollution Bedrock aqqy,uifers 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 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 Unconfined Aquifer Confined Aquifer Hydrogeologic Vocabulary: Pumping wells affect the water in the pores of the aquifer surrounding them forming a cone of depression. IfiddiiIn confined conditions, water pressure from rech hiarge in higher elevation areas can force wells to flow aboveground in lower-lyyging areas. These are called artesian wells or springs. 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 qqy,qy,uality, quantity, and availability . 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 ihin the roc kfks from swampy areas may cause poor water qqyuality from the release of gases from decayed vegetation. Humans Contaminate Groundwater in Many Ways From Jones & Jones, 2003 Humans Contaminate Groundwater in Many Ways An illustration of salt-water encroachment, this can also occur in areas whdhere deep bdkbedrock aqui fers are briny, lklike in Michigan’s rock formations deposited from seas. Exercise: Water Wells & Lithology Brought to you by Core Kids, WMUWMU-- MGRRE Geosciences K-K-1212 Outreach Program Exercise created by Niah Venable, Amanda Walega and SGSusan Grammer w ithbttbNihVblith web content by Niah Venable A special thanks to 8th grade teacher Becky Dalecki, Portage North Middle School and to the 8th grade sc ience teach ers and s tud ent s at M att awan Middl e S ch ool . With generous support from: 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. 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 5C5. Create lihllitholog ic co lumns 6. Calculate the Well Elevation 7. Create stratigraphic columns 8. Create cross-cross-sectionssections for comparison 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 Natural Resources homepage: www.michigan.gov/dnr 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: www.michigan.gov/dnr/1,1607,7www.michigan.gov/dnr/1,1607,7-- 153153--10371_1479310371_14793--3126431264----,00.html,00.html Cliccwd.k Download. 2. Find a Topo Map cont. The ne xt screen sho ws a green and yellow version of a political map with the locations of cities and towns with a blue grid overlay of the qqguadrangle names. Click on the quad labeled “Charlotte” in Eaton and ClCarmel towns hips. 2. Find a Topo Map cont. A pdf of the Charlotte quadrangle will open in Adobe Acrobat. We can save this and use asas--isis or copy and zoom to a portion of the map using MS Word or imaggge handling software. 3. Find Water Well Data Browse to the State of Michigan, Department of Environmental Quality homepage: www.mihiichigan.gov /deq From there click Water, then browse to Drinking Water, to WtWater WllCWell Cons truc tion, th en click on Scanned Water Well Record Retrieval System. AikliktthiA quick link to this page i s: www.deq.state.mi.us/wellwww.deq.state.mi.us/well--logs/logs/ 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 CnttCounty so two sear rhndches need to be done by township, one for Eaton in sections 6, 18 and19d 19; and one f or C armel in sections 12, 13, and 24. We will omit section 7 of EtEaton t ownshi p, d ue t o an absence of usable logs. 3. Find Water Well Data cont. After selectinggy, 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.