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Northern Michigan Wastewater Treatment Operators Annual Meeting Lesa A. Bagby, GeoTrans, Inc.

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Presentation on theme: "Northern Michigan Wastewater Treatment Operators Annual Meeting Lesa A. Bagby, GeoTrans, Inc."— Presentation transcript:

1 Northern Michigan Wastewater Treatment Operators Annual Meeting Lesa A. Bagby, GeoTrans, Inc.

2 Introduction Hydrogeology Overview Water Cycle Groundwater Aquifers Groundwater Quality Groundwater Quantity Water Well Design Groundwater Movement Public Water Supply Wellhead Protection Examples of Michigan Aquifers Unconfined Sand and Gravel - Southeastern Michigan Confined Sandstone – Southcentral Michigan Confined Limestone – Northern Michigan

3 Water Cycle Open System Solar Energy Endless Cycle Evap0ration Precipitation Runoff Infiltration Discharge Ice Caps and Glaciers 2.14 % WW 77.3 % FW 0 % AFW Groundwater 0.16 % WW 22 % FW 98 % AFW Oceans 97.3 % WW 0 % FW 0 % AFW Water Source WW = World’s Water Supply FW = World’s Fresh Water Supply AFW = Available Fresh Water

4 What is Groundwater? Adapted from Applied Ground-water Hydrology and Well Hydraulics, Kasenow, Water Resources Publications, LLC, 1997 Soil Moisture Unsaturated Zone (Vadose) Water Air Used by plants Groundwater Saturated Zone (Phreatic) Water Total Saturation Occurs in many types of soil and rock Used by People

5 Aquifers An aquifer is a geologic unit capable of storing and producing groundwater of consumptive economic importance. Types of Aquifers Formation Type Drift –Unconsolidated (Sand and Gravel) Bedrock – (Sandstone and Limestone) Position in the Subsurface Unconfined Confined Perched

6 Drift Aquifers Drift is unconsolidated material Quality groundwater Thickest drift Clay drift Sand and gravel drift

7 Bedrock Aquifers Occur at the surface as well as under the drift Quality drinking water Primary porosity Secondary porosity Access Prolific bedrock aquifers

8 Unconfined Aquifers Adapted from Manual of Applied Field Hydrogeology, Weight, Sonderegger, McGraw-Hill, 2001 Unsaturated Zone (Vadose) Unconfined Aquifer Confining Layer

9 Confined Aquifers A confined aquifer has a barrier both above and below These barriers are called confining layers Confining layers are made up of geologic materials that greatly slow or restrict the movement of groundwater (such as clay) Water pressure within a confined aquifer is higher than in an unconfined aquifer because of the weight of the overlying formations coupled with their confined nature (because the water cannot escape easily through the confining layers, pressure builds up). Copyright © 2009 International Water Law Project | All Rights Reserved Design by Sidebar Designs | Modified by Gabriel EcksteinGabriel Eckstein

10 Perched Groundwater In areas where a small confining layer is present, above the water table there may be perched groundwater Since the volume of water held in these areas is minimal, they are generally not used as a source of drinking water Water Table Unconfined Aquifer Confining Layer Perched Groundwater Adapted from Applied Ground-water Hydrology and Well Hydraulics, Kasenow, Water Resources Publications, LLC, 1997

11 Groundwater Quality Water molecule Dissolved substances Geologic formations Small quantities Water quality Water quality standards

12 Maximum Contaminant Levels Developed by the United States Environmental Protection Agency Available at tmcl tmcl Provides: The name of the regulated chemical The maximum concentration that the chemical is safe in drinking water The Potential Health Effects Sources of the Contaminant Secondary Contaminant Levels for chemicals that are safe to drink but would affect the taste, color or odor of the drinking water

13 Cleanup Criteria Developed by the Michigan Department of Environmental Quality Available at 07, _4109_ ,00.html 07, _4109_ ,00.html

14 Water Quality Parameters and their Significance ChemicalSourceSignificance Calcium and Magnesium Dissolved from limestone and dolomite Found in brines and sea water Causes hardness and scale-forming properties of water Sodium and Potassium Dissolved from almost all rocks and soils Found in ancient brines, industrial brines, sea water and sewage Found in rock salt used for deicing purposes Causes salty taste in water, may cause foaming in steam boilers, may be harmful to persons on sodium- restricted diets Iron and Manganese Dissolved from almost all rocks and soils, contaminant plumes can increase the dissolution from the soil into the groundwater Causes staining on laundry and fixtures, objectionable taste, interferes with efficiency of water softeners

15 Water Quality Parameters and their Significance continued ChemicalSourceSignificance Bicarbonate and Carbonate Action of carbon dioxide on water on carbonate rocks like limestone and dolomite Produces alkalinity, may form scale and may release carbon dioxide gas in steam boilers ChlorideDissolve from rocks and soils Found in ancient brines, industrial brines, sea water and sewage Found in rock salt used for deicing purposes Causes salty taste in water, may increase corrosive activity of water SulfateDissolved from rocks and soils that contain gypsum, iron sulfides, and other sulfur compounds Found in industrial waste Forms hard scale in steam boilers, gives bitter taste to water, can be beneficial in the brewing process

16 Water Quality Parameters and their Significance continued ChemicalSourceSignificance NitrateDecaying organic material, sewage, nitrates in soil, fertilizers Sign of pollution in individual wells, not usually entire aquifers, promotes algae growth and affect taste of water, may cause methemoglobinemia (Blue Babies) in infants which can be fatal Hydrogen Sulfide Natural decomposition of organic material Causes objectionable odor and taste Trace Metals (like Arsenic) Dissolved from rocks and soil, may be released from plumbing piping, may be released in the presence of organic material (wetlands) Causes adverse health affects at certain levels

17 Maximum Contaminant Level For Arsenic 10 ug/L

18 Maximum Contaminant Level For Nitrate 10 mg/L

19 Saline and Brine Groundwater Secondary Drinking Water Regulatory Level For Total Dissolved Solids 500 mg/L

20 Water Quantity Generally, two aquifer properties are used to evaluate the quantity of water that can be produced from an aquifer: Hydraulic Conductivity - Three-dimensional flow represented by a unit cube Aquifer Thickness – Thickness of the zone of saturation Transmissivity is also used to described an aquifer Transmissivity – Hydraulic conductivity multiplied by aquifer thickness and is a two-dimensional flow represented flow represented by a unit prism

21 Water Quantity continued Rules of thumb The thicker the aquifer the more water will be available for withdrawal relative to thinner aquifers of the same material For unconsolidated aquifers, the coarser the material the higher the Hydraulic Conductivity and subsequently the more water that will be available for withdrawl For bedrock aquifers, fractured rock can produce significantly more water than unfractured rock Silts, clays and shales have low Hydraulic Conductivity and would supply single households, if any

22 Applied Ground-Water Hydrology and Well Hydraulics, Kasenow, Water Resources Publication, LLC, 1997

23 Water Quantity continued Classification of Transmissivity by Magnitude Transmissivity Gallons per day per foot ClassMeaningSupply Potential 120,000IExceptionalA Natural Resource 80,500IIVery HighOf Great Regional Importance 8,050IIIHighOf Regional Importance 805IVIntermediateOf Local Importance 80.50VLowOf Local Value 8.05VIVery LowLimited to Private Supplies <8.05VIIImperceptibleProbably Not an Aquifer Modification of Krasny’s classification, Applied Ground-Water Hydrology and Well Hydraulics, Kasenow, Water Resources Publication, LLC, 1997

24 Water Well Construction Installation methods Dug Drilled Driven Well screens Keeps solids out of well Open boreholes Bedrock wells Sealing ancillary space Typical well depths

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26 Groundwater Movement Influences on movement Temperature Soil Type Geology Rate of movement Generally slow, 3-4 feet per day in sand, inches per day in clay Direction of movement High pressure to low pressure Vertical Lateral Groundwater flow maps

27 Darcy Groundwater Movement Model, Version 2

28 Vertical Cross Section of Groundwater Flow

29 Plan View of Groundwater Flow Calculate Groundwater Elevations Measure depth to water Subtract from top of well casing elvevation Estimate Groundwater Elevation Contours Interpolation between known elevations Direction of Horizontal Flow Perpendicular to the groundwater elevation contours Applied Ground-Water Hydrology and Well Hydraulics 2 nd Edition, Kasenow, Water Resources Publication, LLC2001

30 Public Water Supply Three types in the State of Michigan Type I Type II Type III Type I Hydrogeologic Evaluation Requirements Aquifer Characteristics Transmissivity Direction of Groundwater Flow Safe Yield Water Quality

31 Michigan Type I Wells and Aquifer Test Locations

32 Wellhead Protection Voluntary program to protect public water supply Elements of Wellhead Protection Program Roles and Responsibilities Wellhead Protection Area Delineation Potential Sources of Contamination Wellhead Protection Area Management Contingency Plan New Wells Updates to the Plan

33 Map or list of Wellhead Protection Communities Wellhead Protection Areas in Lower Michigan

34 Review Hydrogeology Overview Water Cycle What is Groundwater? Aquifers Water Quality Water Quantity Water Well Design Groundwater Movement Public Water Supply Wellhead Protection Examples of Michigan Aquifers Semi-Confined Sand and Gravel - Southeastern Michigan Confined Sandstone – South-central Michigan Confined Limestone – Northern Michigan

35 Semi-confined Sand and Gravel

36 Semi-confined Sand and Gravel Aquifer

37 Well Field

38 Semi-Confined Sand and Gravel LocationCity in Southeastern Michigan AquiferUnconfined to Semi-confined sand and gravel from surface grade to a depth of 100-feet. Depth to water is 45-feet, therefore the aquifer thickness is 55-feet Water QualityTrace volatile organic compounds. Source of chemicals from nearby industrial properties. Water treatment includes an air stripper to remove volatile organic compounds from the water supply Water QuantityEstimated transmissivity is 31,000 gallons per day/foot which indicates the aquifer is of regional importance Water Well Design Well field has two wells. Wells are comprised of 12-inch diameter well casings and well screens. The average pump rate for the wells is 180 gallons per minute

39 Confined Sandstone Aquifer

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41 Confined Sandstone Aquifer Down-hole Video

42 Confined Sandstone Aquifer LocationServices portions of four townships in south-central Michigan: Marion, Howell, Oceola and Genoa AquiferConfined sandstone (Marshall Sandstone) from a depth of 120 feet to 420 feet. Depth to water is 32-feet which is higher than that of the top of aquifer demonstrating the confined nature of the aquifer. Water QualityVery good. Treatment is limited to chlorination and water softening. Water QuantityEstimated transmissivity is 200,000 gallons per day/foot which indicates the aquifer is an exceptional natural resource Water Well Design Well field has six wells. Wells are comprised of 12-inch diameter well casings and open boreholes. Average pump rates are 1,400 gallons per minute with an average withdrawal of 1 MGD.

43 Confined Sandstone Aquifer LocationServices portions of four townships in south-central Michigan: Marion, Howell, Oceola and Genoa AquiferConfined sandstone (Marshall Sandstone) from a depth of 120 feet to 420 feet. Depth to water is 32-feet which is higher than that of the top of aquifer demonstrating the confined nature of the aquifer. Water QualityVery good. Treatment is limited to chlorination and water softening. Water QuantityEstimated transmissivity is 200,000 gallons per day/foot which indicates the aquifer is an exceptional natural resource Water Well Design Well field has six wells. Wells are comprised of 12-inch diameter well casings and open boreholes. Average pump rates are 1,400 gallons per minute with an average withdrawal of 1 MGD.

44 Confined Limestone Aquifer

45 Confined Limestone Aquifer Plan View

46 Confined Limestone Aquifer LocationPetoskey, Michigan AquiferConfined limestone (Traverse Limestone) as much as 580 feet thick and highly fractured. Depth to water is above the top of aquifer demonstrating the confined nature of the aquifer. Water QualityVery good. Treatment is limited to chlorination. Water QuantityEstimated transmissivity is 22,000 gallons per day/foot which indicates the aquifer is of regional importance Water Well Design There are 4 well field with 1 production well in each well filed. Wells are comprised of 12-inch diameter well casings and open boreholes. Average pump rates are 1,000 gallons per minute with an average withdrawal of 3 MGD.


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