Transcript Examples of Michigan Aquifers

Northern Michigan Wastewater Treatment Operators
Annual Meeting
Lesa A. Bagby, GeoTrans, Inc.
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
Water Cycle
 Open System
Ice Caps and
 Solar Energy
Glaciers
 Endless2.14
Cycle
% WW
 Evap0ration
77.3 % FW
0 % AFW
 Precipitation
 Runoff
 Infiltration
 Discharge
Groundwater
0.16 % WW
22 % FW
98 % AFW
Oceans
Water Source
WW = World’s Water Supply
97.3 % WW
FW = World’s Fresh Water Supply
0 % FW
AFW = Available Fresh Water
0 % AFW
What is
Groundwater?
Groundwater
Saturated Zone (Phreatic)
• Water
• Total Saturation
• Occurs in many types
of soil and rock
• Used by People
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
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
Drift Aquifers
• Drift is
unconsolidated
material
• Quality groundwater
• Thickest drift
• Clay drift
• Sand and gravel drift
Bedrock Aquifers
• Occur at the surface as
well as under the drift
• Quality drinking water
• Primary porosity
• Secondary porosity
• Access
• Prolific bedrock
aquifers
Unconfined Aquifers
Unsaturated Zone (Vadose)
Unconfined Aquifer
Confining Layer
Adapted from Manual of Applied Field Hydrogeology, Weight, Sonderegger, McGraw-Hill, 2001
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 Eckstein
Perched
Groundwater
In areas where a small confining
layer is present, above the water
table there may be perched
Perched
Groundwater
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
Adapted from Applied Ground-water Hydrology and Well Hydraulics,
Kasenow, Water Resources Publications, LLC, 1997
Groundwater Quality
 Water molecule
 Dissolved substances
 Geologic formations
 Small quantities
 Water quality
 Water quality standards
Maximum
Contaminant Levels
Developed by the United States Environmental Protection
Agency
Available at
http://www.epa.gov/safewater/contaminants/index.html#lis
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
Cleanup Criteria
Developed by the Michigan
Department of Environmental
Quality
Available at
http://www.michigan.gov/deq/0,16
07,7-135-3311_4109_9846-101581-,00.html
Water Quality Parameters and their Significance
Chemical
Source
Significance
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 sodiumrestricted 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
Water Quality Parameters and their Significance continued
Chemical
Source
Significance
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
Chloride
Dissolve 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
Sulfate
Dissolved 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
Water Quality Parameters and their Significance continued
Chemical
Source
Significance
Nitrate
Decaying 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, Causes adverse health affects at
may be released from
certain levels
plumbing piping, may be
released in the presence of
organic material (wetlands)
Maximum Contaminant Level
For Arsenic
10 ug/L
Maximum Contaminant
Level
For Nitrate
10 mg/L
Saline and Brine
Groundwater
Secondary Drinking Water
Regulatory Level
For Total Dissolved Solids
500 mg/L
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
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
Applied Ground-Water Hydrology and Well Hydraulics, Kasenow, Water Resources Publication, LLC, 1997
Water Quantity continued
Classification of Transmissivity by Magnitude
Transmissivity
Gallons per day
per foot
Class
Meaning
Supply Potential
120,000
I
Exceptional
A Natural Resource
80,500
II
Very High
Of Great Regional
Importance
8,050
III
High
Of Regional Importance
805
IV
Intermediate
Of Local Importance
80.50
V
Low
Of Local Value
8.05
VI
Very Low
Limited to Private
Supplies
<8.05
VII
Imperceptible
Probably Not an Aquifer
Modification of Krasny’s classification, Applied Ground-Water Hydrology and Well Hydraulics, Kasenow, Water Resources Publication, LLC, 1997
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
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
Darcy Groundwater Movement
Model, Version 2
Vertical Cross Section of Groundwater Flow
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 2nd Edition, Kasenow, Water Resources Publication, LLC2001
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
Michigan Type I
Wells and Aquifer
Test Locations
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
Wellhead
Protection Areas
in Lower Michigan
Map or list of Wellhead
Protection Communities
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
Semi-confined
Sand and Gravel
Semi-confined
Sand and Gravel
Aquifer
Semi-confined Sand and Gravel Aquifer
Well
Field
Semi-Confined Sand and Gravel
Location
City in Southeastern Michigan
Aquifer
Unconfined 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 Quality
Trace 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 Quantity
Water Well
Design
Estimated transmissivity is 31,000 gallons per day/foot which
indicates the aquifer is of regional importance
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
Confined
Sandstone
Aquifer
Confined
Sandstone
Aquifer
Confined Sandstone Aquifer
Down-hole Video
Confined Sandstone Aquifer
Location
Services portions of four townships in south-central
Michigan: Marion, Howell, Oceola and Genoa
Aquifer
Confined 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 Quality
Very good. Treatment is limited to chlorination and water
softening.
Water Quantity
Water Well
Design
Estimated transmissivity is 200,000 gallons per day/foot
which indicates the aquifer is an exceptional natural
resource
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.
Confined Sandstone Aquifer
Location
Services portions of four townships in south-central
Michigan: Marion, Howell, Oceola and Genoa
Aquifer
Confined 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 Quality
Very good. Treatment is limited to chlorination and water
softening.
Water Quantity
Water Well
Design
Estimated transmissivity is 200,000 gallons per day/foot
which indicates the aquifer is an exceptional natural
resource
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.
Confined
Limestone
Aquifer
Confined
Limestone Aquifer
Plan View
Confined Limestone Aquifer
Location
Petoskey, Michigan
Aquifer
Confined 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 Quality
Very good. Treatment is limited to chlorination.
Water Quantity
Water Well
Design
Estimated transmissivity is 22,000 gallons per day/foot
which indicates the aquifer is of regional importance
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.